Temporal Role for MyD88 in a Model of Brucella-Induced Arthritis and Musculoskeletal Inflammation

PubMed Central

Lacey, Carolyn A.; Mitchell, William J.; Brown, Charles R.

2017-01-01

ABSTRACT Brucella spp. are facultative intracellular Gram-negative bacteria that cause the zoonotic disease brucellosis, one of the most common global zoonoses. Osteomyelitis, arthritis, and musculoskeletal inflammation are common focal complications of brucellosis in humans; however, wild-type (WT) mice infected systemically with conventional doses of Brucella do not develop these complications. Here we report C57BL/6 WT mice infected via the footpad with 103 to 106 CFU of Brucella spp. display neutrophil and monocyte infiltration of the joint space and surrounding musculoskeletal tissue. Joint inflammation is detectable as early as 1 day postinfection and peaks 1 to 2 weeks later, after which WT mice are able to slowly resolve inflammation. B and T cells were dispensable for the onset of swelling but required for resolution of joint inflammation and infection. At early time points, MyD88−/− mice display decreased joint inflammation, swelling, and proinflammatory cytokine levels relative to WT mice. Subsequently, swelling of MyD88−/− joints surpassed WT joint swelling, and resolution of joint inflammation was prolonged. Joint bacterial loads in MyD88−/− mice were significantly greater than those in WT mice by day 3 postinfection and at all time points thereafter. In addition, MyD88−/− joint inflammatory cytokine levels on day 3 and beyond were similar to WT levels. Collectively these data demonstrate MyD88 signaling mediates early inflammatory responses in the joint but also contributes to subsequent clearance of Brucella and resolution of inflammation. This work also establishes a mouse model for studying Brucella-induced arthritis, musculoskeletal complications, and systemic responses, which will lead to a better understanding of focal complications of brucellosis. PMID:28069819

Use of 3D printer model to study vertebral artery anatomy and variations in developmental craniovertebral junction anomalies and as a preoperative tool—an institutional experience

PubMed Central

Chopra, Sanjeev; Kataria, Rashim; Sinha, Virendra Deo

2017-01-01

Background Spinal instrumentation using rods and screws have become procedure of choice for posterior fixation. Vertebral artery anatomy is highly variable in this region posing challenges during surgery. Our study used 3D printer model to understand the anatomy and variations in vertebral artery in live patients thereby providing an accurate idea about vertebral artery injury risk in these patients preoperatively and to rehearse the whole procedure. Methods Ten patients of developmental craniovertebral junction (CVJ) anomalies who were planned for operative intervention in the Department of Neurosurgery at SMS Hospital from February 2016 to December 2016 were analysed using a 3D printer model. Results Out of twenty vertebral arteries studied in ten patients, two were hypoplastic and out of these one could not be appreciated on 3D printer model. Out of remaining nineteen, thirteen arteries were found to lie outside the joint, three were in lateral third, one traversed the middle third of joint and one lied in medial third. In one patient, the vertebral artery was stretched and it traversed horizontally over the joint. Out of ten patients studied, nine were having occipitalised atlas and so entry of these vertebral arteries into cranium were classified as given by Wang et al. into four types. Conclusions By our study, 3D printer model was extremely helpful in analyzing joints and vertebral artery preoperatively and making the surgeon acquainted about the placement and trajectory of the screws accordingly. In our opinion, these models should be included as a basic investigation tool in these patients. PMID:29354734

In Vivo Kinematics of the Tibiotalar and Subtalar Joints in Asymptomatic Subjects: A High-Speed Dual Fluoroscopy Study.

PubMed

Roach, Koren E; Wang, Bibo; Kapron, Ashley L; Fiorentino, Niccolo M; Saltzman, Charles L; Bo Foreman, K; Anderson, Andrew E

2016-09-01

Measurements of joint kinematics are essential to understand the pathomechanics of ankle disease and the effects of treatment. Traditional motion capture techniques do not provide measurements of independent tibiotalar and subtalar joint motion. In this study, high-speed dual fluoroscopy images of ten asymptomatic adults were acquired during treadmill walking at 0.5 m/s and 1.0 m/s and a single-leg, balanced heel-rise. Three-dimensional (3D) CT models of each bone and dual fluoroscopy images were used to quantify in vivo kinematics for the tibiotalar and subtalar joints. Dynamic tibiotalar and subtalar mean joint angles often exhibited opposing trends during captured stance. During both speeds of walking, the tibiotalar joint had significantly greater dorsi/plantarflexion (D/P) angular ROM than the subtalar joint while the subtalar joint demonstrated greater inversion/eversion (In/Ev) and internal/external rotation (IR/ER) than the tibiotalar joint. During balanced heel-rise, only D/P and In/Ev were significantly different between the tibiotalar and subtalar joints. Translational ROM in the anterior/posterior (AP) direction was significantly greater in the subtalar than the tibiotalar joint during walking at 0.5 m/s. Overall, our results support the long-held belief that the tibiotalar joint is primarily responsible for D/P, while the subtalar joint facilitates In/Ev and IR/ER. However, the subtalar joint provided considerable D/P rotation, and the tibiotalar joint rotated about all three axes, which, along with translational motion, suggests that each joint undergoes complex, 3D motion.

3D reconstruction of bony elements of the knee joint and finite element analysis of total knee prosthesis obtained from the reconstructed model.

PubMed

Djoudi, Farid

2013-01-01

Two separate themes are presented in this paper. The first theme is to present a graphical modeling approach of human anatomical structures namely, the femur and the tibia. The second theme involves making a finite element analysis of stresses, displacements and deformations in prosthetic implants (the femoral implant and the polyethylene insert). The graphical modeling approach comes in two parts. The first is the segmentation of MRI scanned images, retrieved in DICOM format for edge detection. In the second part, 3D-CAD models are generated from the results of the segmentation stage. The finite element analysis is done by first extracting the prosthetic implants from the reconstructed 3D-CAD model, then do a finite element analysis of these implants under objectively determined conditions such as; forces, allowed displacements, the materials composing implant, and the coefficient of friction. The objective of this work is to implement an interface for exchanging data between 2D MRI images obtained from a medical diagnosis of a patient and the 3D-CAD model used in various applications, such as; the extraction of the implants, stress analysis at the knee joint and can serve as an aid to surgery, also predict the behavior of the prosthetic implants vis-a-vis the forces acting on the knee joints.

Finding glenoid surface on scapula in 3D medical images for shoulder joint implant operation planning: 3D OCR

NASA Astrophysics Data System (ADS)

Mohammad Sadeghi, Majid; Kececi, Emin Faruk; Bilsel, Kerem; Aralasmak, Ayse

2017-03-01

Medical imaging has great importance in earlier detection, better treatment and follow-up of diseases. 3D Medical image analysis with CT Scan and MRI images has also been used to aid surgeries by enabling patient specific implant fabrication, where having a precise three dimensional model of associated body parts is essential. In this paper, a 3D image processing methodology for finding the plane on which the glenoid surface has a maximum surface area is proposed. Finding this surface is the first step in designing patient specific shoulder joint implant.

Comparison of 3D bone models of the knee joint derived from CT and 3T MR imaging.

PubMed

Neubert, Aleš; Wilson, Katharine J; Engstrom, Craig; Surowiec, Rachel K; Paproki, Anthony; Johnson, Nicholas; Crozier, Stuart; Fripp, Jurgen; Ho, Charles P

2017-08-01

To examine whether magnetic resonance (MR) imaging can offer a viable alternative to computed tomography (CT) based 3D bone modeling. CT and MR (SPACE, TrueFISP, VIBE) images were acquired from the left knee joint of a fresh-frozen cadaver. The distal femur, proximal tibia, proximal fibula and patella were manually segmented from the MR and CT examinations. The MR bone models obtained from manual segmentations of all three sequences were compared to CT models using a similarity measure based on absolute mesh differences. The average absolute distance between the CT and the various MR-based bone models were all below 1mm across all bones. The VIBE sequence provided the best agreement with the CT model, followed by the SPACE, then the TrueFISP data. The most notable difference was for the proximal tibia (VIBE 0.45mm, SPACE 0.82mm, TrueFISP 0.83mm). The study indicates that 3D MR bone models may offer a feasible alternative to traditional CT-based modeling. A single radiological examination using the MR imaging would allow simultaneous assessment of both bones and soft-tissues, providing anatomically comprehensive joint models for clinical evaluation, without the ionizing radiation of CT imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Three-dimensional joint inversion for magnetotelluric resistivity and static shift distributions in complex media

NASA Astrophysics Data System (ADS)

Sasaki, Yutaka; Meju, Max A.

2006-05-01

Accurate interpretation of magnetotelluric (MT) data in the presence of static shift arising from near-surface inhomogeneities is an unresolved problem in three-dimensional (3-D) inversion. While it is well known in 1-D and 2-D studies that static shift can lead to erroneous interpretation, how static shift can influence the result of 3-D inversion is not fully understood and is relevant to improved subsurface analysis. Using the synthetic data generated from 3-D models with randomly distributed heterogeneous overburden and elongate homogeneous overburden that are consistent with geological observations, this paper examines the effects of near-surface inhomogeneity on the accuracy of 3-D inversion models. It is found that small-scale and shallow depth structures are severely distorted while the large-scale structure is marginally distorted in 3-D inversion not accounting for static shift; thus the erroneous near-surface structure does degrade the reconstruction of smaller-scale structure at any depth. However, 3-D joint inversion for resistivity and static shift significantly reduces the artifacts caused by static shifts and improves the overall resolution, irrespective of whether a zero-sum or Gaussian distribution of static shifts is assumed. The 3-D joint inversion approach works equally well for situations where the shallow bodies are of small size or long enough to allow some induction such that the effects of near-surface inhomogeneity are manifested as a frequency-dependent shift rather than a constant shift.

Analysis of the Hexapod Work Space using integration of a CAD/CAE system and the LabVIEW software

NASA Astrophysics Data System (ADS)

Herbuś, K.; Ociepka, P.

2015-11-01

The paper presents the problems related to the integration of a CAD/CAE system with the LabVIEW software. The purpose of the integration is to determine the workspace of a hexapod model basing on a mathematical model describing it motion. In the first stage of the work concerning the integration task the 3D model to simulate movements of a hexapod was elaborated. This phase of the work was done in the “Motion Simulation” module of the CAD/CAE/CAM Siemens NX system. The first step was to define the components of the 3D model in the form of “links”. Individual links were defined according to the nature of the hexapod elements action. In the model prepared for movement simulation were created links corresponding to such elements as: electric actuator, top plate, bottom plate, ball-and-socket joint, toggle joint Phillips. Then were defined the constraints of the “joint” type (e.g.: revolute joint, slider joint, spherical joint) between the created component of the “link” type, so that the computer simulation corresponds to the operation of a real hexapod. The next stage of work included implementing the mathematical model describing the functioning of a hexapod in the LabVIEW software. At this stage, particular attention was paid to determining procedures for integrating the virtual 3D hexapod model with the results of calculations performed in the LabVIEW. The results relate to specific values of the jump of electric actuators depending on the position of the car on the hexapod. The use of integration made it possible to determine the safe operating space of a stationary hexapod taking into consideration the security of a person in the driving simulator designed for the disabled.

Three-dimensional temporomandibular joint modeling and animation.

PubMed

Cascone, Piero; Rinaldi, Fabrizio; Pagnoni, Mario; Marianetti, Tito Matteo; Tedaldi, Massimiliano

2008-11-01

The three-dimensional (3D) temporomandibular joint (TMJ) model derives from a study of the cranium by 3D virtual reality and mandibular function animation. The starting point of the project is high-fidelity digital acquisition of a human dry skull. The cooperation between the maxillofacial surgeon and the cartoonist enables the reconstruction of the fibroconnective components of the TMJ that are the keystone for comprehension of the anatomic and functional features of the mandible. The skeletal model is customized with the apposition of the temporomandibular ligament, the articular disk, the retrodiskal tissue, and the medial and the lateral ligament of the disk. The simulation of TMJ movement is the result of the integration of up-to-date data on the biomechanical restrictions. The 3D TMJ model is an easy-to-use application that may be run on a personal computer for the study of the TMJ and its biomechanics.

Efficient realization of 3D joint inversion of seismic and magnetotelluric data with cross gradient structure constraint

NASA Astrophysics Data System (ADS)

Luo, H.; Zhang, H.; Gao, J.

2016-12-01

Seismic and magnetotelluric (MT) imaging methods are generally used to characterize subsurface structures at various scales. The two methods are complementary to each other and the integration of them is helpful for more reliably determining the resistivity and velocity models of the target region. Because of the difficulty in finding empirical relationship between resistivity and velocity parameters, Gallardo and Meju [2003] proposed a joint inversion method enforcing resistivity and velocity models consistent in structure, which is realized by minimizing cross gradients between two models. However, it is extremely challenging to combine two different inversion systems together along with the cross gradient constraints. For this reason, Gallardo [2007] proposed a joint inversion scheme that decouples the seismic and MT inversion systems by iteratively performing seismic and MT inversions as well as cross gradient minimization separately. This scheme avoids the complexity of combining two different systems together but it suffers the issue of balancing between data fitting and structure constraint. In this study, we have developed a new joint inversion scheme that avoids the problem encountered by the scheme of Gallardo [2007]. In the new scheme, seismic and MT inversions are still separately performed but the cross gradient minimization is also constrained by model perturbations from separate inversions. In this way, the new scheme still avoids the complexity of combining two different systems together and at the same time the balance between data fitting and structure consistency constraint can be enforced. We have tested our joint inversion algorithm for both 2D and 3D cases. Synthetic tests show that joint inversion better reconstructed the velocity and resistivity models than separate inversions. Compared to separate inversions, joint inversion can remove artifacts in the resistivity model and can improve the resolution for deeper resistivity structures. We will also show results applying the new joint seismic and MT inversion scheme to southwest China, where several MT profiles are available and earthquakes are very active.

Joint Inversion Modelling of Geophysical Data From Lough Neagh Basin

NASA Astrophysics Data System (ADS)

Vozar, J.; Moorkamp, M.; Jones, A. G.; Rath, V.; Muller, M. R.

2015-12-01

Multi-dimensional modelling of geophysical data collected in the Lough Neagh Basin is presented in the frame of the IRETHERM project. The Permo-Triassic Lough Neagh Basin, situated in the southeastern part of Northern Ireland, exhibits elevated geothermal gradient (~30 °C/km) in the exploratory drilled boreholes. This is taken to indicate good geothermal exploitation potential in the Sherwood Sandstone aquifer for heating, and possibly even electricity production, purposes. We have used a 3-D joint inversion framework for modelling the magnetotelluric (MT) and gravity data collected to the north of the Lough Neagh to derive robust subsurface geological models. Comprehensive supporting geophysical and geological data (e.g. borehole logs and reflection seismic images) have been used in order to analyze and model the MT and gravity data. The geophysical data sets were provided by the Geological Survey of Northern Ireland (GSNI). Considering correct objective function weighting in favor of noise-free MT response functions is particularly important in joint inversion. There is no simple way how to correct distortion effects the 3-D responses as can be done in 1-D or 2-D case. We have used the Tellus Project airborne EM data to constrain magnetotelluric data and correct them for near surface effects. The shallow models from airborne data are used to constrain the uppermost part of 3-D inversion model. Preliminary 3-D joint inversion modeling reveals that the Sherwood Sandstone Group and the Permian Sandstone Formation are imaged as a conductive zone at the depth range of 500 m to 2000 m with laterally varying thickness, depth, and conductance. The conductive target sediments become shallower and thinner to the north and they are laterally continuous. To obtain better characterization of thermal transport properties of investigated area we used porosity and resistivity data from the Annaghmore and Ballymacilroy boreholes to estimate the relations between porosity/permeability and electrical conductivity. The formulae are based on generalized Archie's law for multiple phases. The conductive layers are interpreted as water bearing or geothermal fluids and estimated porosity and permeability indicates potential to act as geothermal aquifer.

Joint sparse learning for 3-D facial expression generation.

PubMed

Song, Mingli; Tao, Dacheng; Sun, Shengpeng; Chen, Chun; Bu, Jiajun

2013-08-01

3-D facial expression generation, including synthesis and retargeting, has received intensive attentions in recent years, because it is important to produce realistic 3-D faces with specific expressions in modern film production and computer games. In this paper, we present joint sparse learning (JSL) to learn mapping functions and their respective inverses to model the relationship between the high-dimensional 3-D faces (of different expressions and identities) and their corresponding low-dimensional representations. Based on JSL, we can effectively and efficiently generate various expressions of a 3-D face by either synthesizing or retargeting. Furthermore, JSL is able to restore 3-D faces with holes by learning a mapping function between incomplete and intact data. Experimental results on a wide range of 3-D faces demonstrate the effectiveness of the proposed approach by comparing with representative ones in terms of quality, time cost, and robustness.

Human ossicular-joint flexibility transforms the peak amplitude and width of impulsive acoustic stimulia)

PubMed Central

Gottlieb, Peter K.; Vaisbuch, Yona

2018-01-01

The role of the ossicular joints in the mammalian middle ear is still debated. This work tests the hypothesis that the two synovial joints filter potentially damaging impulsive stimuli by transforming both the peak amplitude and width of these impulses before they reach the cochlea. The three-dimensional (3D) velocity along the ossicular chain in unaltered cadaveric human temporal bones (N = 9), stimulated with acoustic impulses, is measured in the time domain using a Polytec (Waldbronn, Germany) CLV-3D laser Doppler vibrometer. The measurements are repeated after fusing one or both of the ossicular joints with dental cement. Sound transmission is characterized by measuring the amplitude, width, and delay of the impulsive velocity profile as it travels from the eardrum to the cochlea. On average, fusing both ossicular joints causes the stapes velocity amplitude and width to change by a factor of 1.77 (p = 0.0057) and 0.78 (p = 0.011), respectively. Fusing just the incudomalleolar joint has a larger effect on amplitude (a factor of 2.37), while fusing just the incudostapedial joint decreases the stapes velocity on average. The 3D motion of the ossicles is altered by fusing the joints. Finally, the ability of current computational models to predict this behavior is also evaluated.

A new algorithm for three-dimensional joint inversion of body wave and surface wave data and its application to the Southern California plate boundary region

NASA Astrophysics Data System (ADS)

Fang, Hongjian; Zhang, Haijiang; Yao, Huajian; Allam, Amir; Zigone, Dimitri; Ben-Zion, Yehuda; Thurber, Clifford; van der Hilst, Robert D.

2016-05-01

We introduce a new algorithm for joint inversion of body wave and surface wave data to get better 3-D P wave (Vp) and S wave (Vs) velocity models by taking advantage of the complementary strengths of each data set. Our joint inversion algorithm uses a one-step inversion of surface wave traveltime measurements at different periods for 3-D Vs and Vp models without constructing the intermediate phase or group velocity maps. This allows a more straightforward modeling of surface wave traveltime data with the body wave arrival times. We take into consideration the sensitivity of surface wave data with respect to Vp in addition to its large sensitivity to Vs, which means both models are constrained by two different data types. The method is applied to determine 3-D crustal Vp and Vs models using body wave and Rayleigh wave data in the Southern California plate boundary region, which has previously been studied with both double-difference tomography method using body wave arrival times and ambient noise tomography method with Rayleigh and Love wave group velocity dispersion measurements. Our approach creates self-consistent and unique models with no prominent gaps, with Rayleigh wave data resolving shallow and large-scale features and body wave data constraining relatively deeper structures where their ray coverage is good. The velocity model from the joint inversion is consistent with local geological structures and produces better fits to observed seismic waveforms than the current Southern California Earthquake Center (SCEC) model.

Hip2Norm: an object-oriented cross-platform program for 3D analysis of hip joint morphology using 2D pelvic radiographs.

PubMed

Zheng, G; Tannast, M; Anderegg, C; Siebenrock, K A; Langlotz, F

2007-07-01

We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.

Three dimensional measurement of minimum joint space width in the knee from stereo radiographs using statistical shape models.

PubMed

van IJsseldijk, E A; Valstar, E R; Stoel, B C; Nelissen, R G H H; Baka, N; Van't Klooster, R; Kaptein, B L

2016-08-01

An important measure for the diagnosis and monitoring of knee osteoarthritis is the minimum joint space width (mJSW). This requires accurate alignment of the x-ray beam with the tibial plateau, which may not be accomplished in practice. We investigate the feasibility of a new mJSW measurement method from stereo radiographs using 3D statistical shape models (SSM) and evaluate its sensitivity to changes in the mJSW and its robustness to variations in patient positioning and bone geometry. A validation study was performed using five cadaver specimens. The actual mJSW was varied and images were acquired with variation in the cadaver positioning. For comparison purposes, the mJSW was also assessed from plain radiographs. To study the influence of SSM model accuracy, the 3D mJSW measurement was repeated with models from the actual bones, obtained from CT scans. The SSM-based measurement method was more robust (consistent output for a wide range of input data/consistent output under varying measurement circumstances) than the conventional 2D method, showing that the 3D reconstruction indeed reduces the influence of patient positioning. However, the SSM-based method showed comparable sensitivity to changes in the mJSW with respect to the conventional method. The CT-based measurement was more accurate than the SSM-based measurement (smallest detectable differences 0.55 mm versus 0. 82 mm, respectively). The proposed measurement method is not a substitute for the conventional 2D measurement due to limitations in the SSM model accuracy. However, further improvement of the model accuracy and optimisation technique can be obtained. Combined with the promising options for applications using quantitative information on bone morphology, SSM based 3D reconstructions of natural knees are attractive for further development.Cite this article: E. A. van IJsseldijk, E. R. Valstar, B. C. Stoel, R. G. H. H. Nelissen, N. Baka, R. van't Klooster, B. L. Kaptein. Three dimensional measurement of minimum joint space width in the knee from stereo radiographs using statistical shape models. Bone Joint Res 2016;320-327. DOI: 10.1302/2046-3758.58.2000626. © 2016 van IJsseldijk et al.

Experimental measurement and modeling analysis on mechanical properties of incudostapedial joint

PubMed Central

Zhang, Xiangming

2011-01-01

The incudostapedial (IS) joint between the incus and stapes is a synovial joint consisting of joint capsule, cartilage, and synovial fluid. The mechanical properties of the IS joint directly affect the middle ear transfer function for sound transmission. However, due to the complexity and small size of the joint, the mechanical properties of the IS joint have not been reported in the literature. In this paper, we report our current study on mechanical properties of human IS joint using both experimental measurement and finite element (FE) modeling analysis. Eight IS joint samples with the incus and stapes attached were harvested from human cadaver temporal bones. Tension, compression, stress relaxation and failure tests were performed on those samples in a micro-material testing system. An analytical approach with the hyperelastic Ogden model and a 3D FE model of the IS joint including the cartilage, joint capsule, and synovial fluid were employed to derive mechanical parameters of the IS joint. The comparison of measurements and modeling results reveals the relationship between the mechanical properties and structure of the IS joint. PMID:21061141

Experimental measurement and modeling analysis on mechanical properties of incudostapedial joint.

PubMed

Zhang, Xiangming; Gan, Rong Z

2011-10-01

The incudostapedial (IS) joint between the incus and stapes is a synovial joint consisting of joint capsule, cartilage, and synovial fluid. The mechanical properties of the IS joint directly affect the middle ear transfer function for sound transmission. However, due to the complexity and small size of the joint, the mechanical properties of the IS joint have not been reported in the literature. In this paper, we report our current study on mechanical properties of human IS joint using both experimental measurement and finite element (FE) modeling analysis. Eight IS joint samples with the incus and stapes attached were harvested from human cadaver temporal bones. Tension, compression, stress relaxation and failure tests were performed on those samples in a micro-material testing system. An analytical approach with the hyperelastic Ogden model and a 3D FE model of the IS joint including the cartilage, joint capsule, and synovial fluid were employed to derive mechanical parameters of the IS joint. The comparison of measurements and modeling results reveals the relationship between the mechanical properties and structure of the IS joint.

Evaluating the Relationship between Team Performance and Joint Attention with Longitudinal Multivariate Mixed Models

DTIC Science & Technology

2016-09-23

Lauren Menke3 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER H0HJ (53290813) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS...as prior work has demonstrated that friendship can facilitate performance in decision-making and motor tasks (e.g., Shah & Jehn, 1993). However, a...Relationship between Team Performance and Joint Attention with Longitudinal Multivariate Mixed Models 5a. CONTRACT NUMBER FA8650-14-D-6501-0009 5b

Rigorous joining of advanced reduced-dimensional beam models to three-dimensional finite element models

NASA Astrophysics Data System (ADS)

Song, Huimin

In the aerospace and automotive industries, many finite element analyses use lower-dimensional finite elements such as beams, plates and shells, to simplify the modeling. These simplified models can greatly reduce the computation time and cost; however, reduced-dimensional models may introduce inaccuracies, particularly near boundaries and near portions of the structure where reduced-dimensional models may not apply. Another factor in creation of such models is that beam-like structures frequently have complex geometry, boundaries and loading conditions, which may make them unsuitable for modeling with single type of element. The goal of this dissertation is to develop a method that can accurately and efficiently capture the response of a structure by rigorous combination of a reduced-dimensional beam finite element model with a model based on full two-dimensional (2D) or three-dimensional (3D) finite elements. The first chapter of the thesis gives the background of the present work and some related previous work. The second chapter is focused on formulating a system of equations that govern the joining of a 2D model with a beam model for planar deformation. The essential aspect of this formulation is to find the transformation matrices to achieve deflection and load continuity on the interface. Three approaches are provided to obtain the transformation matrices. An example based on joining a beam to a 2D finite element model is examined, and the accuracy of the analysis is studied by comparing joint results with the full 2D analysis. The third chapter is focused on formulating the system of equations for joining a beam to a 3D finite element model for static and free-vibration problems. The transition between the 3D elements and beam elements is achieved by use of the stress recovery technique of the variational-asymptotic method as implemented in VABS (the Variational Asymptotic Beam Section analysis). The formulations for an interface transformation matrix and the generalized Timoshenko beam are discussed in this chapter. VABS is also used to obtain the beam constitutive properties and warping functions for stress recovery. Several 3D-beam joint examples are presented to show the convergence and accuracy of the analysis. Accuracy is accessed by comparing the joint results with the full 3D analysis. The fourth chapter provides conclusions from present studies and recommendations for future work.

In vivo kinematic study of the tarsal joints complex based on fluoroscopic 3D-2D registration technique.

PubMed

Chen Wang, M D; Geng, Xiang; Wang, Shaobai; Xin Ma, M D; Xu Wang, M D; Jiazhang Huang, M D; Chao Zhang, M D; Li Chen, M S; Yang, Junsheng; Wang, Kan

2016-09-01

The tarsal bones articulate with each other and demonstrate complicated kinematic characteristics. The in vivo motions of these tarsal joints during normal gait are still unclear. Seven healthy subjects were recruited and fourteen feet in total were tested in the current study. Three dimensional models of the tarsal bones were first created using CT scanning. Corresponding local 3D coordinate systems of each tarsal bone was subsequently established for 6DOF motion decompositions. The fluoroscopy system captured the lateral fluoroscopic images of the targeted tarsal region whilst the subject was walking. Seven key pose images during the stance phase were selected and 3D to 2D bone model registrations were performed on each image to determine joint positions. The 6DOF motions of each tarsal joint during gait were then obtained by connecting these positions together. The TNJ (talo-navicular joint) exhibited the largest ROMs (range of motion) on all rotational directions with 7.39±2.75°of dorsi/plantarflexion, 21.12±4.68°of inversion/eversion, and 16.11±4.44°of internal/external rotation. From heel strike to midstance, the TNJ, STJ (subtalar joint), and CCJ (calcaneao-cuboid joint) were associated with 5.97°, 5.04°, and 3.93°of dorsiflexion; 15.46°, 8.21°, and 5.82°of eversion; and 9.75°, 7.6°, and 4.99°of external rotation, respectively. Likewise, from midstance to heel off, the TNJ, STJ, and CCJ were associated with 6.39, 6.19°, and 4.47°of plantarflexion; 18.57°, 11.86°, and 6.32°of inversion and 13.95°, 9.66°, and 7.58°of internal rotation, respectively. In conclusion, among the tarsal joints, the TNJ exhibited the greatest rotational mobility. Synchronous and homodromous rotational motions were detected for TNJ, STJ, and CCJ during the stance phase. Copyright © 2016 Elsevier B.V. All rights reserved.

Coupling hydrodynamic and wave propagation modeling for waveform modeling of SPE.

NASA Astrophysics Data System (ADS)

Larmat, C. S.; Steedman, D. W.; Rougier, E.; Delorey, A.; Bradley, C. R.

2015-12-01

The goal of the Source Physics Experiment (SPE) is to bring empirical and theoretical advances to the problem of detection and identification of underground nuclear explosions. This paper presents effort to improve knowledge of the processes that affect seismic wave propagation from the hydrodynamic/plastic source region to the elastic/anelastic far field thanks to numerical modeling. The challenge is to couple the prompt processes that take place in the near source region to the ones taking place later in time due to wave propagation in complex 3D geologic environments. In this paper, we report on results of first-principles simulations coupling hydrodynamic simulation codes (Abaqus and CASH), with a 3D full waveform propagation code, SPECFEM3D. Abaqus and CASH model the shocked, hydrodynamic region via equations of state for the explosive, borehole stemming and jointed/weathered granite. LANL has been recently employing a Coupled Euler-Lagrange (CEL) modeling capability. This has allowed the testing of a new phenomenological model for modeling stored shear energy in jointed material. This unique modeling capability has enabled highfidelity modeling of the explosive, the weak grout-filled borehole, as well as the surrounding jointed rock. SPECFEM3D is based on the Spectral Element Method, a direct numerical method for full waveform modeling with mathematical accuracy (e.g. Komatitsch, 1998, 2002) thanks to its use of the weak formulation of the wave equation and of high-order polynomial functions. The coupling interface is a series of grid points of the SEM mesh situated at the edge of the hydrodynamic code domain. Displacement time series at these points are computed from output of CASH or Abaqus (by interpolation if needed) and fed into the time marching scheme of SPECFEM3D. We will present validation tests and waveforms modeled for several SPE tests conducted so far, with a special focus on effect of the local topography.

Resolvin D3 is dysregulated in arthritis and reduces arthritic inflammation

PubMed Central

Arnardottir, Hildur H.; Dalli, Jesmond; Norling, Lucy V.; Colas, Romain A.; Perretti, Mauro; Serhan, Charles N.

2016-01-01

Uncontrolled inflammation is a unifying component of many chronic inflammatory diseases, such as arthritis. Resolvins (Rv) are a new family from the endogenous specialized pro-resolving lipid mediators (SPM) that actively stimulate resolution of inflammation. Herein, using lipid mediator (LM) metabololipidomics with murine joints we found a temporal regulation of endogenous SPM during self-resolving inflammatory arthritis. The SPMs present in self-resolving arthritic joints include the D-series resolvins, e.g. Resolvin (Rv) D1, RvD2, RvD3 and RvD4. Of note, RvD3 levels were reduced in inflamed joints from mice with delayed-resolving arthritis when compared to self-resolving inflammatory arthritis. RvD3 was also reduced in serum from rheumatoid arthritis (RA) patients compared to healthy controls. RvD3 administration reduced joint leukocytes as well as paw joint eicosanoids, clinical scores and edema. Together, these findings provide evidence for dysregulated endogenous RvD3 levels in inflamed paw joints and its potent actions in reducing murine arthritis. PMID:27534559

[Study on the 3D mathematical mode of the muscle groups applied to human mandible by a linear programming method].

PubMed

Wang, Dongmei; Yu, Liniu; Zhou, Xianlian; Wang, Chengtao

2004-02-01

Four types of 3D mathematical mode of the muscle groups applied to the human mandible have been developed. One is based on electromyography (EMG) and the others are based on linear programming with different objective function. Each model contains 26 muscle forces and two joint forces, allowing simulation of static bite forces and concomitant joint reaction forces for various bite point locations and mandibular positions. In this paper, the method of image processing to measure the position and direction of muscle forces according to 3D CAD model was built with CT data. Matlab optimization toolbox is applied to solve the three modes based on linear programming. Results show that the model with an objective function requiring a minimum sum of the tensions in the muscles is reasonable and agrees very well with the normal physiology activity.

Research on joint parameter inversion for an integrated underground displacement 3D measuring sensor.

PubMed

Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

2015-04-13

Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0~30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor.

An Improved 3D Joint Inversion Method of Potential Field Data Using Cross-Gradient Constraint and LSQR Method

NASA Astrophysics Data System (ADS)

Joulidehsar, Farshad; Moradzadeh, Ali; Doulati Ardejani, Faramarz

2018-06-01

The joint interpretation of two sets of geophysical data related to the same source is an appropriate method for decreasing non-uniqueness of the resulting models during inversion process. Among the available methods, a method based on using cross-gradient constraint combines two datasets is an efficient approach. This method, however, is time-consuming for 3D inversion and cannot provide an exact assessment of situation and extension of anomaly of interest. In this paper, the first attempt is to speed up the required calculation by substituting singular value decomposition by least-squares QR method to solve the large-scale kernel matrix of 3D inversion, more rapidly. Furthermore, to improve the accuracy of resulting models, a combination of depth-weighing matrix and compacted constraint, as automatic selection covariance of initial parameters, is used in the proposed inversion algorithm. This algorithm was developed in Matlab environment and first implemented on synthetic data. The 3D joint inversion of synthetic gravity and magnetic data shows a noticeable improvement in the results and increases the efficiency of algorithm for large-scale problems. Additionally, a real gravity and magnetic dataset of Jalalabad mine, in southeast of Iran was tested. The obtained results by the improved joint 3D inversion of cross-gradient along with compacted constraint showed a mineralised zone in depth interval of about 110-300 m which is in good agreement with the available drilling data. This is also a further confirmation on the accuracy and progress of the improved inversion algorithm.

Geometric features of workspace and joint-space paths of 3D reaching movements.

PubMed

Klein Breteler, M D; Meulenbroek, R G; Gielen, S C

1998-11-01

The present study focuses on geometric features of workspace and joint-space paths of three-dimensional reaching movements. Twelve subjects repeatedly performed a three-segment, triangular-shaped movement pattern in an approximately 60 degrees tilted horizontal plane. Task variables elicited movement patterns that varied in position, rotational direction and speed. Trunk, arm, hand and finger-tip movements were recorded by means of a 3D motion-tracking system. Angular excursions of the shoulder and elbow joints were extracted from position data. Analyses of the shape of 3D workspace and joint-space paths focused on the extent to which the submovements were produced in a plane, and on the curvature of the central parts of the submovements. A systematic tendency to produce movements in a plane was found in addition to an increase of finger-tip path curvature with increasing speed. The findings are discussed in relation to the role of optimization principles in trajectory-formation models.

Quantitative detection of cartilage surfaces and ligament geometry of the wrist using an imaging cryomicrotome system.

PubMed

Dvinskikh, N A; Blankevoort, L; Foumani, M; Spaan, J A E; Streekstra, G J

2010-03-22

Biomechanical models may aid in improving diagnosis and treatment of wrist joint disorders. As input, geometrical information is required for model development. Previous studies acquired some elements of the average wrist joint geometry. However, there is a close geometric functional match between articulating surfaces and ligament geometry. Therefore, biomechanical models need to be fed with the geometric data of individual joints. This study is aimed at acquiring geometric data of cartilage surfaces and ligaments from individual wrist joints by using a cryomicrotome imaging system and the evaluation of inter- and intra-observer variability of the data. The 3D geometry of 30 cartilage surfaces and 15 ligaments in three cadaver wrists was manually detected and quantitatively reconstructed. The inter- and intra-observer variability of the cartilage surface detection was 0.14 and 0.19 mm, respectively. For the position of the radius attachment of the dorsal radiocarpal ligament (DRC), the observer variations were 0.12 and 0.65 mm, for intra-/inter-observer, respectively. For the DRC attachment on the triquetrum, the observer variations were 0.22 and 1.19 mm. Anatomic reconstruction from 3D cryomicrotome images offer a method to obtain unique geometry data of the entire wrist joint for modeling purposes. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Hip and knee joints are more stabilized than driven during the stance phase of gait: an analysis of the 3D angle between joint moment and joint angular velocity.

PubMed

Dumas, R; Cheze, L

2008-08-01

Joint power is commonly used in orthopaedics, ergonomics or sports analysis but its clinical interpretation remains controversial. Some basic principles on muscle actions and energy transfer have been proposed in 2D. The decomposition of power on 3 axes, although questionable, allows the same analysis in 3D. However, these basic principles have been widely criticized, mainly because bi-articular muscles must be considered. This requires a more complex computation in order to determine how the individual muscle force contributes to drive the joint. Conversely, with simple 3D inverse dynamics, the analysis of both joint moment and angular velocity directions is essential to clarify when the joint moment can contribute or not to drive the joint. The present study evaluates the 3D angle between the joint moment and the joint angular velocity and investigates when the hip, knee and ankle joints are predominantly driven (angle close to 0 degrees and 180 degrees ) or stabilized (angle close to 90 degrees ) during gait. The 3D angle curves show that the three joints are never fully but only partially driven and that the hip and knee joints are mainly stabilized during the stance phase. The notion of stabilization should be further investigated, especially for subjects with motion disorders or prostheses.

Dynamic 3D scanning as a markerless method to calculate multi-segment foot kinematics during stance phase: methodology and first application.

PubMed

Van den Herrewegen, Inge; Cuppens, Kris; Broeckx, Mario; Barisch-Fritz, Bettina; Vander Sloten, Jos; Leardini, Alberto; Peeraer, Louis

2014-08-22

Multi-segmental foot kinematics have been analyzed by means of optical marker-sets or by means of inertial sensors, but never by markerless dynamic 3D scanning (D3DScanning). The use of D3DScans implies a radically different approach for the construction of the multi-segment foot model: the foot anatomy is identified via the surface shape instead of distinct landmark points. We propose a 4-segment foot model consisting of the shank (Sha), calcaneus (Cal), metatarsus (Met) and hallux (Hal). These segments are manually selected on a static scan. To track the segments in the dynamic scan, the segments of the static scan are matched on each frame of the dynamic scan using the iterative closest point (ICP) fitting algorithm. Joint rotations are calculated between Sha-Cal, Cal-Met, and Met-Hal. Due to the lower quality scans at heel strike and toe off, the first and last 10% of the stance phase is excluded. The application of the method to 5 healthy subjects, 6 trials each, shows a good repeatability (intra-subject standard deviations between 1° and 2.5°) for Sha-Cal and Cal-Met joints, and inferior results for the Met-Hal joint (>3°). The repeatability seems to be subject-dependent. For the validation, a qualitative comparison with joint kinematics from a corresponding established marker-based multi-segment foot model is made. This shows very consistent patterns of rotation. The ease of subject preparation and also the effective and easy to interpret visual output, make the present technique very attractive for functional analysis of the foot, enhancing usability in clinical practice. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Resolvin D3 Is Dysregulated in Arthritis and Reduces Arthritic Inflammation.

PubMed

Arnardottir, Hildur H; Dalli, Jesmond; Norling, Lucy V; Colas, Romain A; Perretti, Mauro; Serhan, Charles N

2016-09-15

Uncontrolled inflammation is a unifying component of many chronic inflammatory diseases, such as arthritis. Resolvins (Rvs) are a new family from the endogenous specialized proresolving mediators (SPMs) that actively stimulate resolution of inflammation. In this study, using lipid mediator metabololipidomics with murine joints we found a temporal regulation of endogenous SPMs during self-resolving inflammatory arthritis. The SPMs present in self-resolving arthritic joints include the D-series Rvs, for example, RvD1, RvD2, RvD3, and RvD4. Of note, RvD3 levels were reduced in inflamed joints from mice with delayed-resolving arthritis when compared with self-resolving inflammatory arthritis. RvD3 was also reduced in serum from rheumatoid arthritis patients compared with healthy controls. RvD3 administration reduced joint leukocytes as well as paw joint eicosanoids, clinical scores, and edema. Taken together, these findings provide evidence for dysregulated endogenous RvD3 levels in inflamed paw joints and its potent actions in reducing murine arthritis. Copyright © 2016 by The American Association of Immunologists, Inc.

Development and validation of a computational model of the knee joint for the evaluation of surgical treatments for osteoarthritis

PubMed Central

Mootanah, R.; Imhauser, C.W.; Reisse, F.; Carpanen, D.; Walker, R.W.; Koff, M.F.; Lenhoff, M.W.; Rozbruch, S.R.; Fragomen, A.T.; Dewan, Z.; Kirane, Y.M.; Cheah, Pamela A.; Dowell, J.K.; Hillstrom, H.J.

2014-01-01

A three-dimensional (3D) knee joint computational model was developed and validated to predict knee joint contact forces and pressures for different degrees of malalignment. A 3D computational knee model was created from high-resolution radiological images to emulate passive sagittal rotation (full-extension to 65°-flexion) and weight acceptance. A cadaveric knee mounted on a six-degree-of-freedom robot was subjected to matching boundary and loading conditions. A ligament-tuning process minimised kinematic differences between the robotically loaded cadaver specimen and the finite element (FE) model. The model was validated by measured intra-articular force and pressure measurements. Percent full scale error between EE-predicted and in vitro-measured values in the medial and lateral compartments were 6.67% and 5.94%, respectively, for normalised peak pressure values, and 7.56% and 4.48%, respectively, for normalised force values. The knee model can accurately predict normalised intra-articular pressure and forces for different loading conditions and could be further developed for subject-specific surgical planning. PMID:24786914

Development and validation of a computational model of the knee joint for the evaluation of surgical treatments for osteoarthritis.

PubMed

Mootanah, R; Imhauser, C W; Reisse, F; Carpanen, D; Walker, R W; Koff, M F; Lenhoff, M W; Rozbruch, S R; Fragomen, A T; Dewan, Z; Kirane, Y M; Cheah, K; Dowell, J K; Hillstrom, H J

2014-01-01

A three-dimensional (3D) knee joint computational model was developed and validated to predict knee joint contact forces and pressures for different degrees of malalignment. A 3D computational knee model was created from high-resolution radiological images to emulate passive sagittal rotation (full-extension to 65°-flexion) and weight acceptance. A cadaveric knee mounted on a six-degree-of-freedom robot was subjected to matching boundary and loading conditions. A ligament-tuning process minimised kinematic differences between the robotically loaded cadaver specimen and the finite element (FE) model. The model was validated by measured intra-articular force and pressure measurements. Percent full scale error between FE-predicted and in vitro-measured values in the medial and lateral compartments were 6.67% and 5.94%, respectively, for normalised peak pressure values, and 7.56% and 4.48%, respectively, for normalised force values. The knee model can accurately predict normalised intra-articular pressure and forces for different loading conditions and could be further developed for subject-specific surgical planning.

Chemometric modeling of 5-Phenylthiophenecarboxylic acid derivatives as anti-rheumatic agents.

PubMed

Adhikari, Nilanjan; Jana, Dhritiman; Halder, Amit K; Mondal, Chanchal; Maiti, Milan K; Jha, Tarun

2012-09-01

Arthritis involves joint inflammation, synovial proliferation and damage of cartilage. Interleukin-1 undergoes acute and chronic inflammatory mechanisms of arthritis. Non-steroidal anti-inflammatory drugs can produce symptomatic relief but cannot act through mechanisms of arthritis. Diseases modifying anti-rheumatoid drugs reduce the symptoms of arthritis like decrease in pain and disability score, reduction of swollen joints, articular index and serum concentration of acute phage proteins. Recently, some literature references are obtained on molecular modeling of antirheumatic agents. We have tried chemometric modeling through 2D-QSAR studies on a dataset of fifty-one compounds out of which forty-four 5-Phenylthiophenecarboxylic acid derivatives have IL-1 inhibitory activity and forty-six 5-Phenylthiophenecarboxylic acid derivatives have %AIA suppressive activity. The work was done to find out the structural requirements of these anti-rheumatic agents. 2D QSAR models were generated by 2D and 3D descriptors by using multiple linear regression and partial least square method where IL-1 antagonism was considered as the biological activity parameter. Statistically significant models were developed on the training set developed by k-means cluster analysis. Sterimol parameters, electronic interaction at atom number 9, 2D autocorrelation descriptors, information content descriptor, average connectivity index chi-3, radial distribution function, Balaban 3D index and 3D-MoRSE descriptors were found to play crucial roles to modulate IL-1 inhibitory activity. 2D autocorrelation descriptors like Broto-Moreau autocorrelation of topological structure-lag 3 weighted by atomic van der Waals volumes, Geary autocorrelation-lag 7 associated with weighted atomic Sanderson electronegativities and 3D-MoRSE descriptors like 3D-MoRSE-signal 22 related to atomic van der Waals volumes, 3D-MoRSE-signal 28 related to atomic van der Waals volumes and 3D-MoRSE-signal 9 which was unweighted, were found to play important roles to model %AIA suppressive activity.

The impact of high-heeled shoes on ankle complex during walking in young women-In vivo kinematic study based on 3D to 2D registration technique.

PubMed

Wang, Chen; Geng, Xiang; Wang, Shaobai; Ma, Xin; Wang, Xu; Huang, Jiazhang; Zhang, Chao; Chen, Li; Yang, Junsheng; Li, Jiabei; Wang, Kan

2016-06-01

To explore the accurate in vivo kinematic changes in the ankle complex when wearing low- and high-heel shoes (LHS and HHS, respectively). Twelve young women were tested unilaterally. Three-dimensional models of the tibia, talus, and calcaneus were first created based on CT scan results. The subjects walked at a self-controlled speed in barefoot, LHS (4cm), and HHS (10cm) conditions. A fluoroscopy system captured the lateral fluoroscopic images of the ankle complex. The images of seven key positions in the stance phase were selected, and 3D to 2D bone model registrations were performed to determine the joint positions. The mean of 6 degree of freedom (DOF) range of motions (ROM), joint positions, and angular displacements of the ankle complex during the gait were then obtained. For the talocrural joint, the rotational ROMs of the subjects either in LHS or HHS condition displayed no significant difference from those in barefoot condition. For the subtalar joint, all the rotational ROMs in the HHS condition and the internal/external rotations in the LHS condition significantly decreased compared with those in the barefoot condition. The talocrural joint was positioned significantly more plantarflexed, inverted, internally rotated, and posteriorly seated in all seven poses in HHS condition, compared with those in barefoot condition. HHS mainly affected the rotational motion of the ankle complex during walking. The talocrural joint position was abnormal, and the subtalar joint ROM decreased during the gait in HHS condition. Only a few kinematic changes occurred in LHS condition relative to the barefoot condition. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Improved Computing Method for 3D Mechanical Connectivity Rates Based on a Polyhedral Simulation Model of Discrete Fracture Network in Rock Masses

NASA Astrophysics Data System (ADS)

Li, Mingchao; Han, Shuai; Zhou, Sibao; Zhang, Ye

2018-06-01

Based on a 3D model of a discrete fracture network (DFN) in a rock mass, an improved projective method for computing the 3D mechanical connectivity rate was proposed. The Monte Carlo simulation method, 2D Poisson process and 3D geological modeling technique were integrated into a polyhedral DFN modeling approach, and the simulation results were verified by numerical tests and graphical inspection. Next, the traditional projective approach for calculating the rock mass connectivity rate was improved using the 3D DFN models by (1) using the polyhedral model to replace the Baecher disk model; (2) taking the real cross section of the rock mass, rather than a part of the cross section, as the test plane; and (3) dynamically searching the joint connectivity rates using different dip directions and dip angles at different elevations to calculate the maximum, minimum and average values of the joint connectivity at each elevation. In a case study, the improved method and traditional method were used to compute the mechanical connectivity rate of the slope of a dam abutment. The results of the two methods were further used to compute the cohesive force of the rock masses. Finally, a comparison showed that the cohesive force derived from the traditional method had a higher error, whereas the cohesive force derived from the improved method was consistent with the suggested values. According to the comparison, the effectivity and validity of the improved method were verified indirectly.

Intensity of joints associated with an extensional fault zone: an estimation by poly3d .

NASA Astrophysics Data System (ADS)

Minelli, G.

2003-04-01

The presence and frequency of joints in sedimentary rocks strongly affects the mechanical and fluid flow properties of the host layers. Joints intensity is evaluated by spacing, S, the distance between neighbouring fractures, or by density, D = 1/S. Joint spacing in layered rocks is often linearly related to layer thickness T, with typical values of 0.5 T < S < 2.0 T . On the other hand, some field cases display very tight joints with S << T and nonlinear relations between spacing and thickness , most of these cases are related to joint system “genetically” related to a nearby fault zone. The present study by using the code Poly3D (Rock Fracture Project at Stanford), numerically explores the effect of the stress distribution in the neighbour of an extensional fault zone with respect to the mapped intensity of joints both in the hanging wall and in the foot wall of it (WILLEMSE, E. J. M., 1997; MARTEL, S. J, AND BOGER, W. A,; 1998). Poly3D is a C language computer program that calculates the displacements, strains and stresses induced in an elastic whole or half-space by planar, polygonal-shaped elements of displacement discontinuity (WILLEMSE, E. J. M., POLLARD, D. D., 2000) Dislocations of varying shapes may be combined to yield complex three-dimensional surfaces well-suited for modeling fractures, faults, and cavities in the earth's crust. The algebraic expressions for the elastic fields around a polygonal element are derived by superposing the solution for an angular dislocation in an elastic half-space. The field data have been collected in a quarry located close to Noci town (Puglia) by using the scan line methodology. In this quarry a platform limestone with a regular bedding with very few shale or marly intercalations displaced by a normal fault are exposed. The comparison between the mapped joints intensity and the calculated stress around the fault displays a good agreement. Nevertheless the intrinsic limitations (isotropic medium and elastic behaviour) of this project encourages other application of Poly3d. References WILLEMSE, E. J. M., 1997, Segmented normal faults: Correspondence between three-dimensional mechanical models and field data: Journal of Geophysical Research, v. 102, p. 675-692. MARTEL, S. J, AND BOGER, W. A, 1998, Geometry and mechanics of secondary fracturing around small three-dimensional faults in granitic rock: Journal of Geophysical Research, v. 103, p. 21,299-21,314. WILLEMSE, E. J. M., POLLARD, D. D., 2000, Normal fault growth: evolution of tipline shapes and slip distribution: in Lehner, F.K. &Urai, J.L. (eds.), Aspects of Tectonic Faulting, Springer -Verlag , Berlin, p. 193-226.

Research on Joint Parameter Inversion for an Integrated Underground Displacement 3D Measuring Sensor

PubMed Central

Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

2015-01-01

Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0 ~ 30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor. PMID:25871714

Calcium plus vitamin D supplementation and joint symptoms in postmenopausal women in the women's health initiative randomized trial.

PubMed

Chlebowski, Rowan T; Pettinger, Mary; Johnson, Karen C; Wallace, Robert; Womack, Catherine; Mossavar-Rahmani, Yasmin; Stefanick, Marcia; Wactawski-Wende, Jean; Carbone, Laura; Lu, Bing; Eaton, Charles; Walitt, Brian; Kooperberg, Charles L

2013-10-01

Low vitamin D intake and levels have been associated with increased joint symptoms in some observational studies but the findings are mixed and evidence from randomized trials sparse. To evaluate the influence of supplemental calcium and vitamin D on joint symptoms in the Women's Health Initiative randomized, placebo-controlled, clinical trial. In post hoc analyses, the results of the Women's Health Initiative randomized clinical trial in which 36,282 postmenopausal women were randomized to receive calcium carbonate (1,000 mg as elemental calcium) with vitamin D-3 (400 IU) daily or placebo were examined in the 6% subgroup of 1,911 participants, oversampled for minorities, who had serial joint symptom assessment. Qualitative information on joint pain and joint swelling was collected by questionnaire before entry and 2 years after randomization. Logistic regression models were used to compare the occurrence and severity of joint symptoms across randomization groups. At baseline, total calcium and vitamin D intakes from diet and supplements were similar in the two randomization groups. In addition, both joint pain (reported by 73%) and joint swelling (reported by 34%) were commonly reported and comparable in the supplement and placebo groups. Two years after randomization, no statistically significant differences between supplement and placebo groups were seen for joint pain frequency (74.6% compared with 75.1% [P=0.79] for supplement and placebo groups, respectively) or joint swelling frequency (34.6% compared with 32.4% [P=0.29], respectively) or in severity scores for either outcome. Subgroup analyses suggested study participants also using nonprotocol calcium supplements at study entry may have less joint pain with supplement group randomization (interaction P=0.02). Joint symptoms are relatively common in postmenopausal women. However, daily supplementation with 1,000 mg calcium carbonate and 400 IU vitamin D-3 in a randomized, placebo-controlled clinical trial setting did not reduce the self-reported frequency or severity of joint symptoms. Copyright © 2013 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Three-dimensional motion of the uncovertebral joint during head rotation.

PubMed

Nagamoto, Yukitaka; Ishii, Takahiro; Iwasaki, Motoki; Sakaura, Hironobu; Moritomo, Hisao; Fujimori, Takahito; Kashii, Masafumi; Murase, Tsuyoshi; Yoshikawa, Hideki; Sugamoto, Kazuomi

2012-10-01

The uncovertebral joints are peculiar but clinically important anatomical structures of the cervical vertebrae. In the aged or degenerative cervical spine, osteophytes arising from an uncovertebral joint can cause cervical radiculopathy, often necessitating decompression surgery. Although these joints are believed to bear some relationship to head rotation, how the uncovertebral joints work during head rotation remains unclear. The purpose of this study is to elucidate 3D motion of the uncovertebral joints during head rotation. Study participants were 10 healthy volunteers who underwent 3D MRI of the cervical spine in 11 positions during head rotation: neutral (0°) and 15° increments to maximal head rotation on each side (left and right). Relative motions of the cervical spine were calculated by automatically superimposing a segmented 3D MR image of the vertebra in the neutral position over images of each position using the volume registration method. The 3D intervertebral motions of all 10 volunteers were standardized, and the 3D motion of uncovertebral joints was visualized on animations using data for the standardized motion. Inferred contact areas of uncovertebral joints were also calculated using a proximity mapping technique. The 3D animation of uncovertebral joints during head rotation showed that the joints alternate between contact and separation. Inferred contact areas of uncovertebral joints were situated directly lateral at the middle cervical spine and dorsolateral at the lower cervical spine. With increasing angle of rotation, inferred contact areas increased in the middle cervical spine, whereas areas in the lower cervical spine slightly decreased. In this study, the 3D motions of uncovertebral joints during head rotation were depicted precisely for the first time.

Jointly reconstructing ground motion and resistivity for ERT-based slope stability monitoring

NASA Astrophysics Data System (ADS)

Boyle, Alistair; Wilkinson, Paul B.; Chambers, Jonathan E.; Meldrum, Philip I.; Uhlemann, Sebastian; Adler, Andy

2018-02-01

Electrical resistivity tomography (ERT) is increasingly being used to investigate unstable slopes and monitor the hydrogeological processes within. But movement of electrodes or incorrect placement of electrodes with respect to an assumed model can introduce significant resistivity artefacts into the reconstruction. In this work, we demonstrate a joint resistivity and electrode movement reconstruction algorithm within an iterative Gauss-Newton framework. We apply this to ERT monitoring data from an active slow-moving landslide in the UK. Results show fewer resistivity artefacts and suggest that electrode movement and resistivity can be reconstructed at the same time under certain conditions. A new 2.5-D formulation for the electrode position Jacobian is developed and is shown to give accurate numerical solutions when compared to the adjoint method on 3-D models. On large finite element meshes, the calculation time of the newly developed approach was also proven to be orders of magnitude faster than the 3-D adjoint method and addressed modelling errors in the 2-D perturbation and adjoint electrode position Jacobian.

Real-time physics-based 3D biped character animation using an inverted pendulum model.

PubMed

Tsai, Yao-Yang; Lin, Wen-Chieh; Cheng, Kuangyou B; Lee, Jehee; Lee, Tong-Yee

2010-01-01

We present a physics-based approach to generate 3D biped character animation that can react to dynamical environments in real time. Our approach utilizes an inverted pendulum model to online adjust the desired motion trajectory from the input motion capture data. This online adjustment produces a physically plausible motion trajectory adapted to dynamic environments, which is then used as the desired motion for the motion controllers to track in dynamics simulation. Rather than using Proportional-Derivative controllers whose parameters usually cannot be easily set, our motion tracking adopts a velocity-driven method which computes joint torques based on the desired joint angular velocities. Physically correct full-body motion of the 3D character is computed in dynamics simulation using the computed torques and dynamical model of the character. Our experiments demonstrate that tracking motion capture data with real-time response animation can be achieved easily. In addition, physically plausible motion style editing, automatic motion transition, and motion adaptation to different limb sizes can also be generated without difficulty.

Multi-view and 3D deformable part models.

PubMed

Pepik, Bojan; Stark, Michael; Gehler, Peter; Schiele, Bernt

2015-11-01

As objects are inherently 3D, they have been modeled in 3D in the early days of computer vision. Due to the ambiguities arising from mapping 2D features to 3D models, 3D object representations have been neglected and 2D feature-based models are the predominant paradigm in object detection nowadays. While such models have achieved outstanding bounding box detection performance, they come with limited expressiveness, as they are clearly limited in their capability of reasoning about 3D shape or viewpoints. In this work, we bring the worlds of 3D and 2D object representations closer, by building an object detector which leverages the expressive power of 3D object representations while at the same time can be robustly matched to image evidence. To that end, we gradually extend the successful deformable part model [1] to include viewpoint information and part-level 3D geometry information, resulting in several different models with different level of expressiveness. We end up with a 3D object model, consisting of multiple object parts represented in 3D and a continuous appearance model. We experimentally verify that our models, while providing richer object hypotheses than the 2D object models, provide consistently better joint object localization and viewpoint estimation than the state-of-the-art multi-view and 3D object detectors on various benchmarks (KITTI [2] , 3D object classes [3] , Pascal3D+ [4] , Pascal VOC 2007 [5] , EPFL multi-view cars[6] ).

Three-dimensional skeletal kinematics of the shoulder girdle and forelimb in walking Alligator

PubMed Central

Baier, David B; Gatesy, Stephen M

2013-01-01

Crocodylians occupy a key phylogenetic position for investigations of archosaur locomotor evolution. Compared to the well-studied hindlimb, relatively little is known about the skeletal movements and mechanics of the forelimb. In this study, we employed manual markerless XROMM (X-ray Reconstruction Of Moving Morphology) to measure detailed 3-D kinematics of the shoulder girdle and forelimb bones of American alligators (Alligator mississippiensis) walking on a treadmill. Digital models of the interclavicle, scapulocoracoid, humerus, radius and ulna were created using a 3-D laser scanner. Models were articulated and aligned to simultaneously recorded frames of fluoroscopic and standard light video to reconstruct and measure joint motion. Joint coordinate systems were established for the coracosternal, glenohumeral and elbow joints. Our analysis revealed that the limb joints only account for about half of fore/aft limb excursion; the remaining excursion results from shoulder girdle movements and lateral bending of the vertebral column. Considerable motion of each scapulocoracoid relative to the vertebral column is consistent with coracosternal mobility. The hemisellar design of the glenohumeral joint permits some additional translation, or sliding in the fore-aft plane, but this movement does not have much of an effect on the distal excursion of the bone. PMID:24102540

A Soft Sensor-Based Three-Dimensional (3-D) Finger Motion Measurement System

PubMed Central

Park, Wookeun; Ro, Kyongkwan; Kim, Suin; Bae, Joonbum

2017-01-01

In this study, a soft sensor-based three-dimensional (3-D) finger motion measurement system is proposed. The sensors, made of the soft material Ecoflex, comprise embedded microchannels filled with a conductive liquid metal (EGaln). The superior elasticity, light weight, and sensitivity of soft sensors allows them to be embedded in environments in which conventional sensors cannot. Complicated finger joints, such as the carpometacarpal (CMC) joint of the thumb are modeled to specify the location of the sensors. Algorithms to decouple the signals from soft sensors are proposed to extract the pure flexion, extension, abduction, and adduction joint angles. The performance of the proposed system and algorithms are verified by comparison with a camera-based motion capture system. PMID:28241414

The Command and Control Reference Model for Modeling, Simulations, and Technology Applications

DTIC Science & Technology

1994-01-20

NUMBER Basic Research Group (BRG), Technical Panel for C3 (TPC3) Joint Directors of Laboratories (JDL) JDL TPC3 BRG NRaD, San Diego , CA 92152; RADC...wind, ionization, pressure, pollution, ... mesofeature (weather, man-made) cloud, storm, fog, smog, dust, fire, jet stream, smoke, aurora borealis

Predictive discomfort in single- and combined-axis whole-body vibration considering different seated postures.

PubMed

DeShaw, Jonathan; Rahmatalla, Salam

2014-08-01

The aim of this study was to develop a predictive discomfort model in single-axis, 3-D, and 6-D combined-axis whole-body vibrations of seated occupants considering different postures. Non-neutral postures in seated whole-body vibration play a significant role in the resulting level of perceived discomfort and potential long-term injury. The current international standards address contact points but not postures. The proposed model computes discomfort on the basis of static deviation of human joints from their neutral positions and how fast humans rotate their joints under vibration. Four seated postures were investigated. For practical implications, the coefficients of the predictive discomfort model were changed into the Borg scale with psychophysical data from 12 volunteers in different vibration conditions (single-axis random fore-aft, lateral, and vertical and two magnitudes of 3-D). The model was tested under two magnitudes of 6-D vibration. Significant correlations (R = .93) were found between the predictive discomfort model and the reported discomfort with different postures and vibrations. The ISO 2631-1 correlated very well with discomfort (R2 = .89) but was not able to predict the effect of posture. Human discomfort in seated whole-body vibration with different non-neutral postures can be closely predicted by a combination of static posture and the angular velocities of the joint. The predictive discomfort model can assist ergonomists and human factors researchers design safer environments for seated operators under vibration. The model can be integrated with advanced computer biomechanical models to investigate the complex interaction between posture and vibration.

Joint inversion of 3-D seismic, gravimetric and magnetotelluric data for sub-basalt imaging in the Faroe-Shetland Basin

NASA Astrophysics Data System (ADS)

Heincke, B.; Moorkamp, M.; Jegen, M.; Hobbs, R. W.

2012-12-01

Imaging of sub-basalt sediments with reflection seismic techniques is limited due to absorption, scattering and transmission effects and the presence of peg-leg multiples. Although many of the difficulties facing conventional seismic profiles can be overcome by recording long offset data resolution of sub-basalt sediments in seismic sections is typically still largely restricted. Therefore multi-parametric approaches in general and joint inversion strategies in particular (e.g. Colombo et al., 2008, Jordan et al., 2012) are considered as alternative to gain additional information from sub-basalt structures. Here, we combine in a 3-D joint inversion first-arrival time tomography, FTG gravity and MT data to identify the base basalt and resolve potential sediments underneath. For sub-basalt exploration the three methods complement each other such that the null space is reduced and significantly better resolved models can be obtained than would be possible by the individual methods: The seismic data gives a robust model for the supra-basalt sediments whilst the gravity field is dominated by the high density basalt and basement features. The MT on the other hand is sensitive to the conductivity in both the supra- and sub-basalt sediments. We will present preliminary individual and joint inversion result for a FTG, seismic and MT data set located in the Faroe-Shetland basin. Because the investigated area is rather large (~75 x 40 km) and the individual data sets are relatively huge, we use a joint inversion framework (see Moorkamp et al., 2011) which is designed to handle large amount of data/model parameters. This program has moreover the options to link the individual parameter models either petrophysically using fixed parameter relationships or structurally using the cross-gradient approach. The seismic data set consists of a pattern of 8 intersecting wide-angle seismic profiles with maximum offsets of up to ~24 km. The 3-D gravity data set (size :~ 30 x 30 km) is collected along parallel lines by a shipborne gradiometer and the marine MT data set is composed of 41 stations that are distributed over the whole investigation area. Logging results from a borehole located in the central part of the investigation area enable us to derive parameter relationships between seismic velocities, resistivities and densities that are adequately describe the rock property behaviors of both the basaltic lava flows and sedimentary layers in this region. In addition, a 3-D reflection seismic survey covering the central part allows us to incorporate the top of basalt and other features as constraints in the joint inversions and to evaluate the quality of the final results. Literature: D. Colombo, M. Mantovani, S. Hallinan, M. Virgilio, 2008. Sub-basalt depth imaging using simultaneous joint inversion of seismic and electromagnetic (MT) data: a CRB field study. SEG Expanded Abstract, Las Vegas, USA, 2674-2678. M. Jordan, J. Ebbing, M. Brönner, J. Kamm , Z. Du, P. Eliasson, 2012. Joint Inversion for Improved Sub-salt and Sub-basalt Imaging with Application to the More Margin. EAGE Expanded Abstracts, Copenhagen, DK. M. Moorkamp, B. Heincke, M. Jegen, A.W.Roberts, R.W. Hobbs, 2011. A framework for 3-D joint inversion of MT, gravity and seismic refraction data. Geophysical Journal International, 184, 477-493.

Scaling depth-induced wave-breaking in two-dimensional spectral wave models

NASA Astrophysics Data System (ADS)

Salmon, J. E.; Holthuijsen, L. H.; Zijlema, M.; van Vledder, G. Ph.; Pietrzak, J. D.

2015-03-01

Wave breaking in shallow water is still poorly understood and needs to be better parameterized in 2D spectral wave models. Significant wave heights over horizontal bathymetries are typically under-predicted in locally generated wave conditions and over-predicted in non-locally generated conditions. A joint scaling dependent on both local bottom slope and normalized wave number is presented and is shown to resolve these issues. Compared to the 12 wave breaking parameterizations considered in this study, this joint scaling demonstrates significant improvements, up to ∼50% error reduction, over 1D horizontal bathymetries for both locally and non-locally generated waves. In order to account for the inherent differences between uni-directional (1D) and directionally spread (2D) wave conditions, an extension of the wave breaking dissipation models is presented. By including the effects of wave directionality, rms-errors for the significant wave height are reduced for the best performing parameterizations in conditions with strong directional spreading. With this extension, our joint scaling improves modeling skill for significant wave heights over a verification data set of 11 different 1D laboratory bathymetries, 3 shallow lakes and 4 coastal sites. The corresponding averaged normalized rms-error for significant wave height in the 2D cases varied between 8% and 27%. In comparison, using the default setting with a constant scaling, as used in most presently operating 2D spectral wave models, gave equivalent errors between 15% and 38%.

Joint and constrained inversions in a complex geological setting, example from the Skellefte District

NASA Astrophysics Data System (ADS)

Garcia Juanatey, M. A.; Lelievre, P. G.; Juhlin, C.; Farquharson, C. G.

2015-12-01

The Skellefte District is a very rich metallogenic province in northern Sweden. It is of Paleoproterozoic age and consists of mainly metavolcanic rocks. Even though the district has been intensively studied, many questions still remain about its emplacement. The complicated structural setting, and the great extension of post-glacial sediments, pose a challenge for geophysical and geological investigations. Most recent research efforts in the area have been directed at the construction of 3D geological models through the combined interpretation of independently modeled geophysical and geological data. Our aim is to take these studies further and derive, through joint and constraint inversions, a common 3D earth model consistent with all the available data. By integrating the datasets already at the modelling stage we intend to reduce significantly the uncertainties associated to the constructed 3D models.The available geophysics in the district includes regional gravity and magnetic data acquired by the Geological Survey of Sweden in the 1970s, four lines of seismic reflection data totalling approximately 70 km, and more than 60 magnetotelluric sites spread across the area. The existing geological data (from surface, borehole, and in-mine observations) is condensed on interpreted surfaces representing the most important lithological boundaries. Additionally, there are density and susceptibility values obtained from samples across the whole district. We are looking for the best way to integrate the different geophysical datasets with geologically-constrained joint and cooperative inversions.

Image based weighted center of proximity versus directly measured knee contact location during simulated gait

PubMed Central

Wang, Hongsheng; Chen, Tony; Koff, Matthew F.; Hutchinson, Ian D.; Gilbert, Susannah; Choi, Dan; Warren, Russell F.; Rodeo, Scott A.; Maher, Suzanne A.

2014-01-01

To understand the mechanical consequences of knee injury requires a detailed analysis of the effect of that injury on joint contact mechanics during activities of daily living. Three-dimensional (3D) knee joint geometric models have been combined with knee joint kinematics to dynamically estimate the location of joint contact during physiological activities – using a weighted center of proximity (WCoP) method. However, the relationship between the estimated WCoP and the actual location of contact has not been defined. The objective of this study was to assess the relationship between knee joint contact location as estimated using the image-based WCoP method, and a directly measured weighted center of contact (WCoC) method during simulated walking. To achieve this goal, we created knee specific models of six human cadaveric knees from magnetic resonance imaging. All knees were then subjected to physiological loads on a knee simulator intended to mimic gait. Knee joint motion was captured using a motion capture system. Knee joint contact stresses were synchronously recorded using a thin electronic sensor throughout gait, and used to compute WCoC for the medial and lateral plateaus of each knee. WCoP was calculated by combining knee kinematics with the MRI-based knee specific model. Both metrics were compared throughout gait using linear regression. The anteroposterior (AP) location of WCoP was significantly correlated with that of WCoC on both tibial plateaus in all specimens (P < 0.01, 95% confidence interval of Person’s coefficient r > 0), but the correlation was not significant in the mediolateral (ML) direction for 4/6 knees (P > 0.05). Our study demonstrates that while the location of joint contact obtained from 3D knee joint contact model, using the WCoP method, is significantly correlated with the location of actual contact stresses in the AP direction, that relationship is less certain in the ML direction. PMID:24837219

Modelling knee flexion effects on joint power absorption and adduction moment.

PubMed

Nagano, Hanatsu; Tatsumi, Ichiroh; Sarashina, Eri; Sparrow, W A; Begg, Rezaul K

2015-12-01

Knee osteoarthritis is commonly associated with ageing and long-term walking. In this study the effects of flexing motions on knee kinetics during stance were simulated. Extended knees do not facilitate efficient loading. It was therefore, hypothesised that knee flexion would promote power absorption and negative work, while possibly reducing knee adduction moment. Three-dimensional (3D) position and ground reaction forces were collected from the right lower limb stance phase of one healthy young male subject. 3D position was sampled at 100 Hz using three Optotrak Certus (Northern Digital Inc.) motion analysis camera units, set up around an eight metre walkway. Force plates (AMTI) recorded ground reaction forces for inverse dynamics calculations. The Visual 3D (C-motion) 'Landmark' function was used to change knee joint positions to simulate three knee flexion angles during static standing. Effects of the flexion angles on joint kinetics during the stance phase were then modelled. The static modelling showed that each 2.7° increment in knee flexion angle produced 2.74°-2.76° increments in knee flexion during stance. Increased peak extension moment was 6.61 Nm per 2.7° of increased knee flexion. Knee flexion enhanced peak power absorption and negative work, while decreasing adduction moment. Excessive knee extension impairs quadriceps' power absorption and reduces eccentric muscle activity, potentially leading to knee osteoarthritis. A more flexed knee is accompanied by reduced adduction moment. Research is required to determine the optimum knee flexion to prevent further damage to knee-joint structures affected by osteoarthritis. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved l1-SPIRiT using 3D walsh transform-based sparsity basis.

PubMed

Feng, Zhen; Liu, Feng; Jiang, Mingfeng; Crozier, Stuart; Guo, He; Wang, Yuxin

2014-09-01

l1-SPIRiT is a fast magnetic resonance imaging (MRI) method which combines parallel imaging (PI) with compressed sensing (CS) by performing a joint l1-norm and l2-norm optimization procedure. The original l1-SPIRiT method uses two-dimensional (2D) Wavelet transform to exploit the intra-coil data redundancies and a joint sparsity model to exploit the inter-coil data redundancies. In this work, we propose to stack all the coil images into a three-dimensional (3D) matrix, and then a novel 3D Walsh transform-based sparsity basis is applied to simultaneously reduce the intra-coil and inter-coil data redundancies. Both the 2D Wavelet transform-based and the proposed 3D Walsh transform-based sparsity bases were investigated in the l1-SPIRiT method. The experimental results show that the proposed 3D Walsh transform-based l1-SPIRiT method outperformed the original l1-SPIRiT in terms of image quality and computational efficiency. Copyright © 2014 Elsevier Inc. All rights reserved.

A validated method for modeling anthropoid hip abduction in silico.

PubMed

Hammond, Ashley S; Plavcan, J Michael; Ward, Carol V

2016-07-01

The ability to reconstruct hip joint mobility from femora and pelves could provide insight into the locomotion and paleobiology of fossil primates. This study presents a method for modeling hip abduction in anthropoids validated with in vivo data. Hip abduction simulations were performed on a large sample of anthropoids. The modeling approach integrates three-dimensional (3D) polygonal models created from laser surface scans of bones, 3D landmark data, and shape analysis software to digitally articulate and manipulate the hip joint. Range of femoral abduction (degrees) and the abducted knee position (distance spanned at the knee during abduction) were compared with published live animal data. The models accurately estimate knee position and (to a lesser extent) angular abduction across broad locomotor groups. They tend to underestimate abduction for acrobatic or suspensory taxa, but overestimate it in more stereotyped taxa. Correspondence between in vivo and in silico data varies at the specific and generic level. Our models broadly correspond to in vivo data on hip abduction, although the relationship between the models and live animal data is less straightforward than hypothesized. The models can predict acrobatic or stereotyped locomotor adaptation for taxa with values near the extremes of the range of abduction ability. Our findings underscore the difficulties associated with modeling complex systems and the importance of validating in silico models. They suggest that models of joint mobility can offer additional insight into the functional abilities of extinct primates when done in consideration of how joints move and function in vivo. Am J Phys Anthropol 160:529-548, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Lamination effects on a 3D model of the magnetic core of power transformers

NASA Astrophysics Data System (ADS)

Poveda-Lerma, Antonio; Serrano-Callergues, Guillermo; Riera-Guasp, Martin; Pineda-Sanchez, Manuel; Puche-Panadero, Ruben; Perez-Cruz, Juan

2017-12-01

In this paper the lamination effect on the model of a power transformer's core with stacked E-I structure is analyzed. The distribution of the magnetic flux in the laminations depends on the stacking method. In this work it is shown, using a 3D FEM model and an experimental prototype, that the non-uniform distribution of the flux in a laminated E-I core with alternate-lap joint stack increases substantially the average value of the magnetic flux density in the core, compared with a butt joint stack. Both the simulated model and the experimental tests show that the presence of constructive air-gaps in the E-I junctions gives rise to a zig-zag flux in the depth direction. This inter-lamination flux reduces the magnetic flux density in the I-pieces and increases substantially the magnetic flux density in the E-pieces, with highly saturated points that traditional 2D analysis cannot reproduce. The relation between the number of laminations included in the model, and the computational resourses needed to build it, is also evaluated in this work.

TH-A-18C-02: An Electrostatic Model for Assessment of Joint Space Morphology in Cone-Beam CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Q; Thawait, G; Gang, G

Purpose: High-resolution cone-beam CT (CBCT) of the extremities presents a potentially valuable basis for image-based biomarkers of arthritis, trauma, and risk of injury. We present a new method for 3D joint space analysis that exploits the high isotropic spatial resolution of CBCT and is sensitive to small changes in disease-related morphology. Methods: The approach uses an “electrostatic” model in which joint surfaces (e.g., distal femur and proximal tibia) are labeled as charge densities between which the electric field is solved by approximation to the Laplace equation. The method yields a unique solution determined by the field lines across the “capacitor”more » and is hypothesized to be more sensitive than conventional (Sharp) scores and immune to degeneracies that limit simple distance-along-axis or closest-point analysis. The algorithm was validated in CBCT phantom images and applied in two clinical scenarios: osteoarthritis (OA, change in loadbearing tibiofemoral joint space); and assessment of injury risk (correlation of 3D joint space to tibial slope). Results: Joint space maps computed from the electrostatic model were accurate to within the voxel size (0.26 mm). The method highlighted subtle regions of morphological change that would likely be missed by conventional scalar metrics. Regions of subtle cartilage erosion were well quantified, and the method confidently discriminated OA and non-OA cohorts. 3D joint space maps correlated well with tibial slope and provide a new basis for principal component analysis of loadbearing injury risk. Runtime was less than 5 min (235×235×121 voxel subvolume in Matlab). Conclusion: A new method for joint space assessment was reported as a possible image-based biomarker of subtle articular change. The algorithm yields accurate quantitation of the joint in a manner that is robust against operator and patient setup variation. The method shows promising initial results in ongoing trials of CBCT in osteoarthritis, rheumatoid arthritis, and injury risk assessment. Research supported by R01 and R21 grants from the National Institutes of Health, academic-industry partnership with Carestream Health, and a grant from the US Army Natick Soldier Research, Development and Engineering Center.« less

Canine stifle joint biomechanics associated with tibial plateau leveling osteotomy predicted by use of a computer model.

PubMed

Brown, Nathan P; Bertocci, Gina E; Marcellin-Little, Denis J

2014-07-01

To evaluate effects of tibial plateau leveling osteotomy (TPLO) on canine stifle joint biomechanics in a cranial cruciate ligament (CrCL)-deficient stifle joint by use of a 3-D computer model simulating the stance phase of gait and to compare biomechanics in TPLO-managed, CrCL-intact, and CrCL-deficient stifle joints. Computer simulations of the pelvic limb of a Golden Retriever. A previously developed computer model of the canine pelvic limb was used to simulate TPLO stabilization to achieve a tibial plateau angle (TPA) of 5° (baseline value) in a CrCL-deficient stifle joint. Sensitivity analysis was conducted for tibial fragment rotation of 13° to -3°. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared with values for CrCL-intact and CrCL-deficient stifle joints. TPLO with a 5° TPA converted cranial tibial translation to caudal tibial translation and increased loads placed on the remaining stifle joint ligaments, compared with results for a CrCL-intact stifle joint. Lateral collateral ligament load was similar, medial collateral ligament load increased, and caudal cruciate ligament load decreased after TPLO, compared with loads for a CrCL-deficient stifle joint. Relative tibial rotation after TPLO was similar to that of a CrCL-deficient stifle joint. Stifle joint biomechanics were affected by TPLO fragment rotation. In the model, stifle joint biomechanics were partially improved after TPLO, compared with CrCL-deficient stifle joint biomechanics, but TPLO did not fully restore CrCL-intact stifle joint biomechanics. Overrotation of the tibial fragment negatively influenced stifle joint biomechanics by increasing caudal tibial translation.

A three-dimensional back-analysis of the collapse of an underground cavity in soft rocks

NASA Astrophysics Data System (ADS)

Fazio, Nunzio Luciano; Lollino, Piernicola; Perrotti, Michele; Parise, Mario; Bonamini, Marco; Di Maggio, Cipriano; Madonia, Giuliana; Vattano, Marco

2016-04-01

Anthropogenic sinkholes have recently occurred in built-up areas of Sicily (southern Italy) and are generally associated with the presence of ancient underground quarries for the extraction of soft calcarenite rock, used as building material. These quarries were poorly excavated and then were abandoned in the following decades; urban expansion has recently enlarged to involve the areas affected by presence of the cavities, so that the likely collapse of the underground systems poses serious risks to people, buildings and infrastructures. The present work focuses on the case of the town of Marsala, where in 2003 a sinkhole opened at the outskirts of town, near peri-urban buildings. Field surveys, structural analysis of the joint networks in the rock mass and numerical modeling were carried out in order to investigate the most significant factors responsible of the instability processes of the underground quarry. In particular, a geotechnical three-dimensional model has been defined based on in-situ measurements and surveys. The FEM analyses have been performed with the code Plaxis-3D, by using initially the Mohr-Coulomb elasto-plastic model and then assessing the influence of the joint systems on the rock-mass stability with a jointed rock anisotropic model. Discrete planar bands have been also used to simulate the effect of specific joints, as an alternative to the jointed rock model. The results are in good agreement with the failure mechanism generated during the 2003 sinkhole event, and confirm that reliable analyses of these problems requires 3-D sophisticated tools.

Analysis of the stress-strain state in single overlap joints using piezo-ceramic actuators

NASA Astrophysics Data System (ADS)

Pǎltânea, Veronica; Pǎltânea, Gheorghe; Popovici, Dorina; Jiga, Gabriel; Papanicolaou, George

2014-05-01

In this paper is presented a 2D approach to finite element modeling and an analytical calculus of a single lap bonded joint. As adherent material were selected a sheet of wood, aluminum and titanium. For adhesive part were selected Bison Super Wood D3 in case of the wood single lap joint and an epoxy resin type DGEBA-TETA for gluing together aluminum and titanium parts. In the article is described a combined method, which consists in the placement of the piezoelectric actuator inside of the adhesive part, in order to determine the tensile stress in the overlap joint. A comparison between the analytical and numerical results has been achieved through a multiphysics modeling - electrical and mechanical coupled problem. The technique used to calculate the mechanical parameters (First Principal Stress, displacements) was the three-point bending test, where different forces were applied in the mid-span of the structure, in order to maintain a constant displacement rate. The length of the overlap joint was modified from 20 to 50 mm.

Trans-dimensional joint inversion of seabed scattering and reflection data.

PubMed

Steininger, Gavin; Dettmer, Jan; Dosso, Stan E; Holland, Charles W

2013-03-01

This paper examines joint inversion of acoustic scattering and reflection data to resolve seabed interface roughness parameters (spectral strength, exponent, and cutoff) and geoacoustic profiles. Trans-dimensional (trans-D) Bayesian sampling is applied with both the number of sediment layers and the order (zeroth or first) of auto-regressive parameters in the error model treated as unknowns. A prior distribution that allows fluid sediment layers over an elastic basement in a trans-D inversion is derived and implemented. Three cases are considered: Scattering-only inversion, joint scattering and reflection inversion, and joint inversion with the trans-D auto-regressive error model. Including reflection data improves the resolution of scattering and geoacoustic parameters. The trans-D auto-regressive model further improves scattering resolution and correctly differentiates between strongly and weakly correlated residual errors.

KmL3D: a non-parametric algorithm for clustering joint trajectories.

PubMed

Genolini, C; Pingault, J B; Driss, T; Côté, S; Tremblay, R E; Vitaro, F; Arnaud, C; Falissard, B

2013-01-01

In cohort studies, variables are measured repeatedly and can be considered as trajectories. A classic way to work with trajectories is to cluster them in order to detect the existence of homogeneous patterns of evolution. Since cohort studies usually measure a large number of variables, it might be interesting to study the joint evolution of several variables (also called joint-variable trajectories). To date, the only way to cluster joint-trajectories is to cluster each trajectory independently, then to cross the partitions obtained. This approach is unsatisfactory because it does not take into account a possible co-evolution of variable-trajectories. KmL3D is an R package that implements a version of k-means dedicated to clustering joint-trajectories. It provides facilities for the management of missing values, offers several quality criteria and its graphic interface helps the user to select the best partition. KmL3D can work with any number of joint-variable trajectories. In the restricted case of two joint trajectories, it proposes 3D tools to visualize the partitioning and then export 3D dynamic rotating-graphs to PDF format. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reedlunn, Benjamin

Room D was an in-situ, isothermal, underground experiment conducted at the Waste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under-predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recentlymore » by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under-predict Room D vertical closure by 3.1×. A list of potential improvements is discussed.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reedlunn, Benjamin

Room D was an in-situ, isothermal, underground experiment conducted at theWaste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recentlymore » by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under predict Room D vertical closure by 3.1×. A list of potential improvements is discussed.« less

Position of the prosthesis and the incidence of dislocation following total hip replacement.

PubMed

He, Rong-xin; Yan, Shi-gui; Wu, Li-dong; Wang, Xiang-hua; Dai, Xue-song

2007-07-05

Dislocation is the second most common complication of hip replacement surgery, and impact of the prosthesis is believed to be the fundamental reason. The present study employed Solidworks 2003 and MSC-Nastran software to analyze the three dimensional variables in order to investigate how to prevent dislocation following hip replacement surgery. Computed tomography (CT) imaging was used to collect femoral outline data and Solidworks 2003 software was used to construct the cup model with variabilities. Nastran software was used to evaluate dislocation at different prosthesis positions and different geometrical shapes. Three dimensional movement and results from finite element method were analyzed and the values of dislocation resistance index (DRI), range of motion to impingement (ROM-I), range of motion to dislocation (ROM-D) and peak resisting moment (PRM) were determined. Computer simulation was used to evaluate the range of motion of the hip joint at different prosthesis positions. Finite element analysis showed: (1) Increasing the ratio of head/neck increased the ROM-I values and moderately increased ROM-D and PRM values. Increasing the head size significantly increased PRM and to some extent ROM-I and ROM-D values, which suggested that there would be a greater likelihood of dislocation. (2) Increasing the anteversion angle increased the ROM-I, ROM-D, PRM, energy required for dislocation (ENERGY-D) and DRI values, which would increase the stability of the joint. (3) As the chamber angle was increased, ROM-I, ROM-D, PRM, Energy-D and DRI values were increased, resulting in improved joint stability. Chamber angles exceeding 55 degrees resulted in increases in ROM-I and ROM-D values, but decreases in PRM, Energy-D, and DRI values, which, in turn, increased the likelihood of dislocation. (4) The cup, which was reduced posteriorly, reduced ROM-I values (2.1 -- 5.3 degrees ) and increased the DRI value (0.073). This suggested that the posterior high side had the effect of 10 degrees anteversion angle. Increasing the head/neck ratio increases joint stability. Posterior high side reduced the range of motion of the joint but increased joint stability; Increasing the anteversion angle increases DRI values and thus improve joint stability; Increasing the chamber angle increases DRI values and improves joint stability. However, at angles exceeding 55 degrees , further increases in the chamber angle result in decreased DRI values and reduce the stability of the joint.

Joint positions matter for ultrasound examination of RA patients-increased power Doppler signal in neutral versus flat position of hands.

PubMed

Husic, Rusmir; Lackner, Angelika; Stradner, Martin H; Hermann, Josef; Dejaco, Christian

2017-08-01

Position of joints might influence the result of US examination in patients with RA. The purpose of this work was to compare grey-scale (GS) and power Doppler (PWD) findings obtained in neutral vs flat position of hands. A cross-sectional study of 42 RA patients with active disease. Two dimensional and 3D sonography of wrists and MCP joints were conducted in two different joint positions: neutral position, which is a slight flexion of the fingers with relaxed extensor muscles; and flat position, where all palm and volar sides of fingers touch the Table. Two dimensional GS synovitis (GSS) and PWD signals were scored semi-quantitatively (0-3). For 3D sonography, the percentage of PWD voxels within a region of interest was calculated. GSS was not quantified using 3D sonography. Compared with neutral position, 2D PWD signals disappeared in 28.3% of joints upon flattening. The median global 2D PWD score (sum of all PWD scores of an individual patient) decreased from 8 to 3 ( P < 0.001), and the global 3D PWD voxel score from 3.8 to 0.9 ( P < 0.001). The reduction of PWD scores was similar in all joints (2D: minus 50%, 3D: minus 66.4-80.1%). Inter- and intrareader agreement of PWD results was good (intraclass correlation coefficient: 0.75-0.82). In RA, a neutral position of the hands is linked to a higher sensitivity of 2D and 3D sonography in detecting PWD signals at wrists and MCP joints, compared with a flat position. Standardization of the scanning procedure is essential for obtaining comparable US results in RA patients in trials and clinical routines. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

On the generation of tangential ground motion by underground explosions in jointed rocks

NASA Astrophysics Data System (ADS)

Vorobiev, Oleg; Ezzedine, Souheil; Antoun, Tarabay; Glenn, Lewis

2015-03-01

This paper describes computational studies of tangential ground motions generated by spherical explosions in a heavily jointed granite formation. Various factors affecting the shear wave generation are considered, including joint spacing, orientation and frictional properties. Simulations are performed both in 2-D for a single joint set to elucidate the basic response mechanisms, and in 3-D for multiple joint sets to realistically represent in situ conditions in a realistic geological setting. The joints are modelled explicitly using both contact elements and weakness planes in the material. Simulations are performed both deterministically and stochastically to quantify the effects of geological uncertainties on near field ground motions. The mechanical properties of the rock and the joints as well as the joint spacing and orientation are taken from experimental test data and geophysical logs corresponding to the Climax Stock granitic outcrop, which is the geological setting of the source physics experiment (SPE). Agreement between simulation results and near field wave motion data from SPE enables newfound understanding of the origin and extent of non-spherical motions associated with underground explosions in fractured geological media.

The relationship between clinical characteristics, radiographic osteoarthritis and 3D bone area: data from the osteoarthritis initiative.

PubMed

Barr, A J; Dube, B; Hensor, E M A; Kingsbury, S R; Peat, G; Bowes, M A; Conaghan, P G

2014-10-01

Radiographic measures of osteoarthritis (OA) are based upon two dimensional projection images. Active appearance modelling (AAM) of knee magnetic resonance imaging (MRI) enables accurate, 3D quantification of joint structures in large cohorts. This cross-sectional study explored the relationship between clinical characteristics, radiographic measures of OA and 3D bone area (tAB). Clinical data and baseline paired radiographic and MRI data, from the medial compartment of one knee of 2588 participants were obtained from the NIH Osteoarthritis Initiative (OAI). The medial femur (MF) and tibia (MT) tAB were calculated using AAM. 'OA-attributable' tAB (OA-tAB) was calculated using data from regression models of tAB of knees without OA. Associations between OA-tAB and radiographic measures of OA were investigated using linear regression. In univariable analyses, height, weight, and age in female knees without OA explained 43.1%, 32.1% and 0.1% of the MF tAB variance individually and 54.4% when included simultaneously in a multivariable model. Joint space width (JSW), osteophytes and sclerosis explained just 5.3%, 14.9% and 10.1% of the variance of MF OA-tAB individually and 17.4% when combined. Kellgren Lawrence (KL) grade explained approximately 20% of MF OA-tAB individually. Similar results were seen for MT OA-tAB. Height explained the majority of variance in tAB, confirming an allometric relationship between body and joint size. Radiographic measures of OA, derived from a single radiographic projection, accounted for only a small amount of variation in 3D knee OA-tAB. The additional structural information provided by 3D bone area may explain the lack of a substantive relationship with these radiographic OA measures. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Advanced Multivariate Inversion Techniques for High Resolution 3D Geophysical Modeling

DTIC Science & Technology

2011-09-01

of seismic ambient noise – has been used to image crustal Vs variation with a lateral resolution upward of 100 km either on regional or on sub...to East Africa, we solve for velocity structure in an area with less lateral heterogeneity but great tectonic complexity. To increase the...demonstrate correlation with crustal geology. Figure 1 shows the 3D S-wave velocity model obtained from the joint inversion. The low-velocity anomaly

A Unified Approach to Joint Regional/Teleseismic Calibration and Event Location with a 3D Earth Model

DTIC Science & Technology

2010-09-01

raytracing and travel-time calculation in 3D Earth models, such as the finite-difference eikonal method (e.g., Podvin and Lecomte, 1991), fast...by Reiter and Rodi (2009) in constructing JWM. Two teleseismic data sets were considered, both extracted from the EHB database (Engdahl et al...extracted from the updated EHB database distributed by the International Seismological Centre (http://www.isc.ac.uk/EHB/index.html). The new database

Measurement of body joint angles for physical therapy based on mean shift tracking using two low cost Kinect images.

PubMed

Chen, Y C; Lee, H J; Lin, K H

2015-08-01

Range of motion (ROM) is commonly used to assess a patient's joint function in physical therapy. Because motion capture systems are generally very expensive, physical therapists mostly use simple rulers to measure patients' joint angles in clinical diagnosis, which will suffer from low accuracy, low reliability, and subjective. In this study we used color and depth image feature from two sets of low-cost Microsoft Kinect to reconstruct 3D joint positions, and then calculate moveable joint angles to assess the ROM. A Gaussian background model is first used to segment the human body from the depth images. The 3D coordinates of the joints are reconstructed from both color and depth images. To track the location of joints throughout the sequence more precisely, we adopt the mean shift algorithm to find out the center of voxels upon the joints. The two sets of Kinect are placed three meters away from each other and facing to the subject. The joint moveable angles and the motion data are calculated from the position of joints frame by frame. To verify the results of our system, we take the results from a motion capture system called VICON as golden standard. Our 150 test results showed that the deviation of joint moveable angles between those obtained by VICON and our system is about 4 to 8 degree in six different upper limb exercises, which are acceptable in clinical environment.

[Research progress of three-dimensional printing technique in joint surgery].

PubMed

Wang, Fuyou; Ren, Xiang; Yang, Liu

2014-03-01

To summarize the application status of three-dimensional (3-D) printing technique in joint surgery and look forward to the future research directions. The recent original articles about the application and research of 3-D printing technique in joint surgery were extensively reviewed and analyzed. In clinical applications, 3-D printing technique can provide "tailored" treatment and custom implants for patients, which helps doctors to perform the complex operations easier and more safely; in fundamental research, tissue engineered scaffolds with desirable external shape and internal organization are easily fabricated with 3-D printing technique, which can meet the demand of cell adherence and proliferation. Even more, cells may be deposited with the biomaterials during the printing. With the development of medical imaging, digital medicine and new materials, 3-D printing technique will have a wider range of applications in joint surgery.

Advanced Multivariate Inversion Techniques for High Resolution 3D Geophysical Modeling (Invited)

NASA Astrophysics Data System (ADS)

Maceira, M.; Zhang, H.; Rowe, C. A.

2009-12-01

We focus on the development and application of advanced multivariate inversion techniques to generate a realistic, comprehensive, and high-resolution 3D model of the seismic structure of the crust and upper mantle that satisfies several independent geophysical datasets. Building on previous efforts of joint invesion using surface wave dispersion measurements, gravity data, and receiver functions, we have added a fourth dataset, seismic body wave P and S travel times, to the simultaneous joint inversion method. We present a 3D seismic velocity model of the crust and upper mantle of northwest China resulting from the simultaneous, joint inversion of these four data types. Surface wave dispersion measurements are primarily sensitive to seismic shear-wave velocities, but at shallow depths it is difficult to obtain high-resolution velocities and to constrain the structure due to the depth-averaging of the more easily-modeled, longer-period surface waves. Gravity inversions have the greatest resolving power at shallow depths, and they provide constraints on rock density variations. Moreover, while surface wave dispersion measurements are primarily sensitive to vertical shear-wave velocity averages, body wave receiver functions are sensitive to shear-wave velocity contrasts and vertical travel-times. Addition of the fourth dataset, consisting of seismic travel-time data, helps to constrain the shear wave velocities both vertically and horizontally in the model cells crossed by the ray paths. Incorporation of both P and S body wave travel times allows us to invert for both P and S velocity structure, capitalizing on empirical relationships between both wave types’ seismic velocities with rock densities, thus eliminating the need for ad hoc assumptions regarding the Poisson ratios. Our new tomography algorithm is a modification of the Maceira and Ammon joint inversion code, in combination with the Zhang and Thurber TomoDD (double-difference tomography) program.

Intra-articular injection of micronized dehydrated human amnion/chorion membrane attenuates osteoarthritis development

PubMed Central

2014-01-01

Introduction Micronized dehydrated human amnion/chorion membrane (μ-dHACM) is derived from donated human placentae and has anti-inflammatory, low immunogenic and anti-fibrotic properties. The objective of this study was to quantitatively assess the efficacy of μ-dHACM as a disease modifying intervention in a rat model of osteoarthritis (OA). It was hypothesized that intra-articular injection of μ-dHACM would attenuate OA progression. Methods Lewis rats underwent medial meniscal transection (MMT) surgery to induce OA. Twenty four hours post-surgery, μ-dHACM or saline was injected intra-articularly into the rat joint. Naïve rats also received μ-dHACM injections. Microstructural changes in the tibial articular cartilage were assessed using equilibrium partitioning of an ionic contrast agent (EPIC-μCT) at 21 days post-surgery. The joint was also evaluated histologically and synovial fluid was analyzed for inflammatory markers at 3 and 21 days post-surgery. Results There was no measured baseline effect of μ-dHACM on cartilage in naïve animals. Histological staining of treated joints showed presence of μ-dHACM in the synovium along with local hypercellularity at 3 and 21 days post-surgery. In MMT animals, development of cartilage lesions at 21 days was prevented and number of partial erosions was significantly reduced by treatment with μ-dHACM. EPIC-μCT analysis quantitatively showed that μ-dHACM reduced proteoglycan loss in MMT animals. Conclusions μ-dHACM is rapidly sequestered in the synovial membrane following intra-articular injection and attenuates cartilage degradation in a rat OA model. These data suggest that intra-articular delivery of μ-dHACM may have a therapeutic effect on OA development. PMID:24499554

Augmented virtuality for arthroscopic knee surgery.

PubMed

Li, John M; Bardana, Davide D; Stewart, A James

2011-01-01

This paper describes a computer system to visualize the location and alignment of an arthroscope using augmented virtuality. A 3D computer model of the patient's joint (from CT) is shown, along with a model of the tracked arthroscopic probe and the projection of the camera image onto the virtual joint. A user study, using plastic bones instead of live patients, was made to determine the effectiveness of this navigated display; the study showed that the navigated display improves target localization in novice residents.

The Use of IMMUs in a Water Environment: Instrument Validation and Application of 3D Multi-Body Kinematic Analysis in Medicine and Sport

PubMed Central

Mangia, Anna Lisa; Cortesi, Matteo; Fantozzi, Silvia; Giovanardi, Andrea; Borra, Davide; Gatta, Giorgio

2017-01-01

The aims of the present study were the instrumental validation of inertial-magnetic measurements units (IMMUs) in water, and the description of their use in clinical and sports aquatic applications applying customized 3D multi-body models. Firstly, several tests were performed to map the magnetic field in the swimming pool and to identify the best volume for experimental test acquisition with a mean dynamic orientation error lower than 5°. Successively, the gait and the swimming analyses were explored in terms of spatiotemporal and joint kinematics variables. The extraction of only spatiotemporal parameters highlighted several critical issues and the joint kinematic information has shown to be an added value for both rehabilitative and sport training purposes. Furthermore, 3D joint kinematics applied using the IMMUs provided similar quantitative information than that of more expensive and bulky systems but with a simpler and faster setup preparation, a lower time consuming processing phase, as well as the possibility to record and analyze a higher number of strides/strokes without limitations imposed by the cameras. PMID:28441739

The Use of IMMUs in a Water Environment: Instrument Validation and Application of 3D Multi-Body Kinematic Analysis in Medicine and Sport.

PubMed

Mangia, Anna Lisa; Cortesi, Matteo; Fantozzi, Silvia; Giovanardi, Andrea; Borra, Davide; Gatta, Giorgio

2017-04-22

The aims of the present study were the instrumental validation of inertial-magnetic measurements units (IMMUs) in water, and the description of their use in clinical and sports aquatic applications applying customized 3D multi-body models. Firstly, several tests were performed to map the magnetic field in the swimming pool and to identify the best volume for experimental test acquisition with a mean dynamic orientation error lower than 5°. Successively, the gait and the swimming analyses were explored in terms of spatiotemporal and joint kinematics variables. The extraction of only spatiotemporal parameters highlighted several critical issues and the joint kinematic information has shown to be an added value for both rehabilitative and sport training purposes. Furthermore, 3D joint kinematics applied using the IMMUs provided similar quantitative information than that of more expensive and bulky systems but with a simpler and faster setup preparation, a lower time consuming processing phase, as well as the possibility to record and analyze a higher number of strides/strokes without limitations imposed by the cameras.

Automated 3D quantitative assessment and measurement of alpha angles from the femoral head-neck junction using MR imaging

NASA Astrophysics Data System (ADS)

Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S.; Walker, Duncan; Crozier, Stuart; Engstrom, Craig

2015-10-01

To develop an automated approach for 3D quantitative assessment and measurement of alpha angles from the femoral head-neck (FHN) junction using bone models derived from magnetic resonance (MR) images of the hip joint. Bilateral MR images of the hip joints were acquired from 30 male volunteers (healthy active individuals and high-performance athletes, aged 18-49 years) using a water-excited 3D dual echo steady state (DESS) sequence. In a subset of these subjects (18 water-polo players), additional True Fast Imaging with Steady-state Precession (TrueFISP) images were acquired from the right hip joint. For both MR image sets, an active shape model based algorithm was used to generate automated 3D bone reconstructions of the proximal femur. Subsequently, a local coordinate system of the femur was constructed to compute a 2D shape map to project femoral head sphericity for calculation of alpha angles around the FHN junction. To evaluate automated alpha angle measures, manual analyses were performed on anterosuperior and anterior radial MR slices from the FHN junction that were automatically reformatted using the constructed coordinate system. High intra- and inter-rater reliability (intra-class correlation coefficients  >  0.95) was found for manual alpha angle measurements from the auto-extracted anterosuperior and anterior radial slices. Strong correlations were observed between manual and automatic measures of alpha angles for anterosuperior (r  =  0.84) and anterior (r  =  0.92) FHN positions. For matched DESS and TrueFISP images, there were no significant differences between automated alpha angle measures obtained from the upper anterior quadrant of the FHN junction (two-way repeated measures ANOVA, F  <  0.01, p  =  0.98). Our automatic 3D method analysed MR images of the hip joints to generate alpha angle measures around the FHN junction circumference with very good reliability and reproducibility. This work has the potential to improve analyses of cam-type lesions of the FHN junction for large-scale morphometric and clinical MR investigations of the human hip region.

Lamb Wave Polarization Techniques for Structural Damage Localization and Quantification

DTIC Science & Technology

2011-11-01

11  Figure 11. Images showing (a) fatigued aluminum dog bone specimen with 53-mm crack and (b) 3-D SLDV test...Abaqus* and a 3-D model of a plate girder. Experimental measurements using piezoelectric ( PZT ) sensors were located on the web in pulse-echo mode, and...analyzed mode conversion of T- joint with collocated PZT sensors before and after the stiffener using a 2-D simulation under plane strain assumptions

Measurement of Rayleigh wave Z/H ratio and joint inversion for a high-resolution S wave velocity model beneath the Gulf of Mexico passive margin

NASA Astrophysics Data System (ADS)

Miao, W.; Li, G.; Niu, F.

2016-12-01

Knowledge on the 3D sediment structure beneath the Gulf of Mexico passive margin is not only important to explore the oil and gas resources in the area, but also essential to decipher the deep crust and mantle structure beneath the margin with teleseismic data. In this study, we conduct a joint inversion of Rayleigh wave ellipticity and phase velocity at 6-40 s to construct a 3-D S wave velocity model in a rectangular area of 100°-87° west and 28°-37° north. We use ambient noise data from a total of 215 stations of the Transportable Array deployed under the Earthscope project. Rayleigh wave ellipticity, or Rayleigh wave Z/H (vertical to horizontal) amplitude ratio is mostly sensitive to shallow sediment structure, while the dispersion data are expected to have reasonably good resolution to uppermost mantle depths. The Z/H ratios measured from stations inside the Gulf Coastal Plain are distinctly lower in comparison with those measured from the inland stations. We also measured the phase velocity dispersion from the same ambient noise dataset. Our preliminary 3-D model is featured by strong low-velocity anomalies at shallow depth, which are spatially well correlated with Gulf Cost, East Texas, and the Lower Mississippi basins. We will discuss other features of the 3-D models once the model is finalized.

Accurate 3D kinematic measurement of temporomandibular joint using X-ray fluoroscopic images

NASA Astrophysics Data System (ADS)

Yamazaki, Takaharu; Matsumoto, Akiko; Sugamoto, Kazuomi; Matsumoto, Ken; Kakimoto, Naoya; Yura, Yoshiaki

2014-04-01

Accurate measurement and analysis of 3D kinematics of temporomandibular joint (TMJ) is very important for assisting clinical diagnosis and treatment of prosthodontics and orthodontics, and oral surgery. This study presents a new 3D kinematic measurement technique of the TMJ using X-ray fluoroscopic images, which can easily obtain the TMJ kinematic data in natural motion. In vivo kinematics of the TMJ (maxilla and mandibular bone) is determined using a feature-based 2D/3D registration, which uses beads silhouette on fluoroscopic images and 3D surface bone models with beads. The 3D surface models of maxilla and mandibular bone with beads were created from CT scans data of the subject using the mouthpiece with the seven strategically placed beads. In order to validate the accuracy of pose estimation for the maxilla and mandibular bone, computer simulation test was performed using five patterns of synthetic tantalum beads silhouette images. In the clinical applications, dynamic movement during jaw opening and closing was conducted, and the relative pose of the mandibular bone with respect to the maxilla bone was determined. The results of computer simulation test showed that the root mean square errors were sufficiently smaller than 1.0 mm and 1.0 degree. In the results of clinical application, during jaw opening from 0.0 to 36.8 degree of rotation, mandibular condyle exhibited 19.8 mm of anterior sliding relative to maxillary articular fossa, and these measurement values were clinically similar to the previous reports. Consequently, present technique was thought to be suitable for the 3D TMJ kinematic analysis.

Implementation of a gait cycle loading into healthy and meniscectomised knee joint models with fibril-reinforced articular cartilage.

PubMed

Mononen, Mika E; Jurvelin, Jukka S; Korhonen, Rami K

2015-01-01

Computational models can be used to evaluate the functional properties of knee joints and possible risk locations within joints. Current models with fibril-reinforced cartilage layers do not provide information about realistic human movement during walking. This study aimed to evaluate stresses and strains within a knee joint by implementing load data from a gait cycle in healthy and meniscectomised knee joint models with fibril-reinforced cartilages. A 3D finite element model of a knee joint with cartilages and menisci was created from magnetic resonance images. The gait cycle data from varying joint rotations, translations and axial forces were taken from experimental studies and implemented into the model. Cartilage layers were modelled as a fibril-reinforced poroviscoelastic material with the menisci considered as a transversely isotropic elastic material. In the normal knee joint model, relatively high maximum principal stresses were specifically predicted to occur in the medial condyle of the knee joint during the loading response. Bilateral meniscectomy increased stresses, strains and fluid pressures in cartilage on the lateral side, especially during the first 50% of the stance phase of the gait cycle. During the entire stance phase, the superficial collagen fibrils modulated stresses of cartilage, especially in the medial tibial cartilage. The present computational model with a gait cycle and fibril-reinforced biphasic cartilage revealed time- and location-dependent differences in stresses, strains and fluid pressures occurring in cartilage during walking. The lateral meniscus was observed to have a more significant role in distributing loads across the knee joint than the medial meniscus, suggesting that meniscectomy might initiate a post-traumatic process leading to osteoarthritis at the lateral compartment of the knee joint.

Advanced Fabrication Techniques for Precisely Controlled Micro and Nano Scale Environments for Complex Tissue Regeneration and Biomedical Applications

NASA Astrophysics Data System (ADS)

Holmes, Benjamin

As modern medicine advances, it is still very challenging to cure joint defects due to their poor inherent regenerative capacity, complex stratified architecture, and disparate biomechanical properties. The current clinical standard for catastrophic or late stage joint degradation is a total joint implant, where the damaged joint is completely excised and replaced with a metallic or artificial joint. However, these procedures still only lasts for 10-15 years, and there are hosts of recovery complications which can occur. Thus, these studies have sought to employ advanced biomaterials and scaffold fabricated techniques to effectively regrow joint tissue, instead of merely replacing it with artificial materials. We can hypothesize here that the inclusion of biomimetic and bioactive nanomaterials with highly functional electrospun and 3D printed scaffold can improve physical characteristics (mechanical strength, surface interactions and nanotexture) enhance cellular growth and direct stem cell differentiation for bone, cartilage and vascular growth as well as cancer metastasis modeling. Nanomaterial inclusion and controlled 3D printed features effectively increased nano surface roughness, Young's Modulus and provided effective flow paths for simulated arterial blood. All of the approaches explored proved highly effective for increasing cell growth, as a result of increasing micro-complexity and nanomaterial incorporation. Additionally, chondrogenic and osteogenic differentiation, cell migration, cell to cell interaction and vascular formation were enhanced. Finally, growth-factor(gf)-loaded polymer nanospheres greatly improved vascular cell behavior, and provided a highly bioactive scaffold for mesenchymal stem cell (MSC) and human umbilical vein endothelial cell (HUVEC) co-culture and bone formation. In conclusion, electrospinning and 3D printing when combined effectively with biomimetic and bioactive nanomaterials (i.e. carbon nanomaterials, collagen, nHA, polymer drug delivery nanospheres) can provide high performance, functional materials that also serve as effective tissue forming 3D environments. Both general science knowledge and the translational potential of tissue engineered constructs were advanced by original contributions to the fields for tissue engineering and orthopedic medicine. The most original advancement of general science comes from a successful combination of advanced nanomaterials and biomaterials with existing 3D printing and CAD design to support multiple types of cells and tissues. Future translation of these technologies was advanced due to the highly functional nature of these constructs (i.e. mechanical and hydrodynamic characteristics). Future work would involve more evaluation of vascular neogenesis, small animal models to evaluate bioactivity and biocompatibility and large clinically relevant animals to measure gross tissue formation and biomechanical performance.

Biomechanical validation of finite element models for two silicone metacarpophalangeal joint implants.

PubMed

Hussein, A I; Stranart, J C; Meguid, S A; Bogoch, E R

2011-02-01

Silicone implants are used for prosthetic arthroplasty of metacarpophalangeal (MCP) joints severely damaged by rheumatoid arthritis. Different silicone elastomer MCP implant designs have been developed, including the Swanson and the NeuFlex implants. The goal of this study was to compare the in vitro mechanical behavior of Swanson and NeuFlex MCP joint implants. Three-dimensional (3D) finite element (FE) models of the silicone implants were modeled using the commercial software ANSYS and subjected to angular displacement from 0 deg to 90 deg. FE models were validated using mechanical tests of implants incrementally bent from 0 deg to 90 deg in a joint simulator. Swanson size 2 and 4 implants were compared with NeuFlex size 10 and 30 implants, respectively. Good agreement was observed throughout the range of motion for the flexion bending moment derived from 3D FE models and mechanical tests. From 30 deg to 90 deg, the Swanson 2 demonstrated a greater resistance to deformation than the NeuFlex 10 and required a greater bending moment for joint flexion. For larger implant sizes, the NeuFlex 30 had a steeper moment-displacement curve, but required a lower moment than the Swanson 4, due to implant preflexion. On average, the stress generated at the implant hinge from 30 deg to 90 deg was lower in the NeuFlex than in the Swanson. On average, starting from the neutral position of 30 deg for the preflexed NeuFlex implant, higher moments were required to extend the NeuFlex implants to 0 deg compared with the Swanson implants, which returned spontaneously to resting position. Implant toggling within the medullary canals was less in the NeuFlex than in the Swanson. The differential performance of these implants may be useful in implant selection based on the preoperative condition(s) of the joint and specific patient functional needs.

Application of Archimedean copulas to the analysis of drought decadal variation in China

NASA Astrophysics Data System (ADS)

Zuo, Dongdong; Feng, Guolin; Zhang, Zengping; Hou, Wei

2017-12-01

Based on daily precipitation data collected from 1171 stations in China during 1961-2015, the monthly standardized precipitation index was derived and used to extract two major drought characteristics which are drought duration and severity. Next, a bivariate joint model was established based on the marginal distributions of the two variables and Archimedean copula functions. The joint probability and return period were calculated to analyze the drought characteristics and decadal variation. According to the fit analysis, the Gumbel-Hougaard copula provided the best fit to the observed data. Based on four drought duration classifications and four severity classifications, the drought events were divided into 16 drought types according to the different combinations of duration and severity classifications, and the probability and return period were analyzed for different drought types. The results showed that the occurring probability of six common drought types (0 < D ≤ 1 and 0.5 < S ≤ 1, 1 < D ≤ 3 and 0.5 < S ≤ 1, 1 < D ≤ 3 and 1 < S ≤ 1.5, 1 < D ≤ 3 and 1.5 < S ≤ 2, 1 < D ≤ 3 and 2 < S, and 3 < D ≤ 6 and 2 < S) accounted for 76% of the total probability of all types. Moreover, due to their greater variation, two drought types were particularly notable, i.e., the drought types where D ≥ 6 and S ≥ 2. Analyzing the joint probability in different decades indicated that the location of the drought center had a distinctive stage feature, which cycled from north to northeast to southwest during 1961-2015. However, southwest, north, and northeast China had a higher drought risk. In addition, the drought situation in southwest China should be noted because the joint probability values, return period, and the analysis of trends in the drought duration and severity all indicated a considerable risk in recent years.

Application of the perfectly matched layer in 3-D marine controlled-source electromagnetic modelling

NASA Astrophysics Data System (ADS)

Li, Gang; Li, Yuguo; Han, Bo; Liu, Zhan

2018-01-01

In this study, the complex frequency-shifted perfectly matched layer (CFS-PML) in stretching Cartesian coordinates is successfully applied to 3-D frequency-domain marine controlled-source electromagnetic (CSEM) field modelling. The Dirichlet boundary, which is usually used within the traditional framework of EM modelling algorithms, assumes that the electric or magnetic field values are zero at the boundaries. This requires the boundaries to be sufficiently far away from the area of interest. To mitigate the boundary artefacts, a large modelling area may be necessary even though cell sizes are allowed to grow toward the boundaries due to the diffusion of the electromagnetic wave propagation. Compared with the conventional Dirichlet boundary, the PML boundary is preferred as the modelling area of interest could be restricted to the target region and only a few absorbing layers surrounding can effectively depress the artificial boundary effect without losing the numerical accuracy. Furthermore, for joint inversion of seismic and marine CSEM data, if we use the PML for CSEM field simulation instead of the conventional Dirichlet, the modelling area for these two different geophysical data collected from the same survey area could be the same, which is convenient for joint inversion grid matching. We apply the CFS-PML boundary to 3-D marine CSEM modelling by using the staggered finite-difference discretization. Numerical test indicates that the modelling algorithm using the CFS-PML also shows good accuracy compared to the Dirichlet. Furthermore, the modelling algorithm using the CFS-PML shows advantages in computational time and memory saving than that using the Dirichlet boundary. For the 3-D example in this study, the memory saving using the PML is nearly 42 per cent and the time saving is around 48 per cent compared to using the Dirichlet.

Modeling Computer Communication Networks in a Realistic 3D Environment

DTIC Science & Technology

2010-03-01

50 2. Comparison of visualization tools . . . . . . . . . . . . . . . . . 75 xi List of Abbreviations Abbreviation Page 2D two-dimensional...International Conference on, 77 –84, 2001. 20. National Defense and the Canadian Forces. “Joint Fires Support”. URL http: //www.cfd-cdf.forces.gc.ca/sites/ page ...Table of Contents Page Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Acknowledgements

Development of three-dimensional prints of arthritic joints for supporting patients' awareness to structural damage.

PubMed

Kleyer, Arnd; Beyer, Laura; Simon, Christoph; Stemmler, Fabian; Englbrecht, Matthias; Beyer, Christian; Rech, Jürgen; Manger, Bernhard; Krönke, Gerhard; Schett, Georg; Hueber, Axel J

2017-02-10

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) result in severe joint destruction and functional disability if left untreated. We aim to develop tools that help patients with RA and PsA to understand and experience the impact of inflammatory joint disease on the integrity of their (juxta-articular) bone and increase adherence to medical treatment. In this study, we used high-resolution peripheral quantitative computed tomography (HR-pQCT) to develop 3D prototypes of patients' finger joints. HR-pQCT (XtremeCT, Scanco) measurements were performed in healthy individuals and patients with inflammatory joint disease, followed by a 3D print using the objet30 printer. Healthy participants (n = 10), and patients (n = 15 with RA and 15 with PsA) underwent a detailed, standardized interview with demonstration of printed joints. Utilizing HR-pQCT images of metacarpophalangeal (MCP) heads, high quality and exact 3D prints as prototypes were created. Erosions in different sizes and the trabecular network printed in detail were visualized, demonstrating structural reduction in arthritic vs. healthy bone. After demonstration of 3D prints (healthy vs. erosive joint, visual and haptic) 26/39 (66%) participants (including healthy volunteers) were deeply affected, often quoting "shock". Of the patients with RA and PsA, 13/15 (86%) and 11/15 (73%), respectively, stated that they would rethink their attitude to medication adherence. More importantly, 21/24 patients with RA or PsA (87.5%) expressed that they would have wished to see such 3D prints during their first disease-specific conversations. Using arthro-haptic 3D printed prototypes of joints may help to better understand the impact of inflammatory arthritides on bone integrity and long-term damage.

Conversion of IVA Human Computer Model to EVA Use and Evaluation and Comparison of the Result to Existing EVA Models

NASA Technical Reports Server (NTRS)

Hamilton, George S.; Williams, Jermaine C.

1998-01-01

This paper describes the methods, rationale, and comparative results of the conversion of an intravehicular (IVA) 3D human computer model (HCM) to extravehicular (EVA) use and compares the converted model to an existing model on another computer platform. The task of accurately modeling a spacesuited human figure in software is daunting: the suit restricts the human's joint range of motion (ROM) and does not have joints collocated with human joints. The modeling of the variety of materials needed to construct a space suit (e. g. metal bearings, rigid fiberglass torso, flexible cloth limbs and rubber coated gloves) attached to a human figure is currently out of reach of desktop computer hardware and software. Therefore a simplified approach was taken. The HCM's body parts were enlarged and the joint ROM was restricted to match the existing spacesuit model. This basic approach could be used to model other restrictive environments in industry such as chemical or fire protective clothing. In summary, the approach provides a moderate fidelity, usable tool which will run on current notebook computers.

The usage of the three-dimension distractor in the NAVID system for plagiocephaly-three case reports.

PubMed

Osawa, Hirokatsu; Kato, Mihoko; Nagakura, Masamune; Morishita, Tsuyoshi; Kondo, Goro; Kurimoto, Michihiro

2015-12-01

Distraction osteogenesis is a standard method for craniosynostosis. However, the technique using conventional devices still has some disadvantages, especially for anterior or posterior plagiocephaly with complex deformities. In the Nakajima's angle-variable internal distraction (NAVID) system originally for maxillary surgeries, the cranial three-dimension (D) distractor with three dimensionally movable joint at the anterior arm has been developed recently in order to prevent the interference in the distraction process and excessive force. In this paper, we first reported two cases of anterior plagiocephaly, and one case of posterior plagiocephaly received distraction osteogenesis using new 3-D distractor in the NAVID system. In two cases of anterior plagiocephaly, the reshaping of supra-orbital bar in reference of simulating by the 3-D skull model was performed. In all cases, we fixed two paralleled 2-D distractors and a 3-D distractor in the upper frontal or parietal region. Within the limitations of this study, we believe that the NAVID system is suitable for infant plagiocephaly due to the simple and small joint arm. Furthermore, the usage of the 3-D distractor would reduce the interference with 2-D distractors and easily lead to attainment of targeted distracting distance.

On the generation of horizontal shear waves by underground explosions in jointed rocks

DOE PAGES

Vorobiev, Oleg; Ezzedine, Souheil; Antoun, Tarabay; ...

2015-02-04

This paper describes computational studies of non-spherical ground motions generated by spherical explosions in a heavily jointed granite formation. Various factors affecting the shear wave generation are considered, including joint spacing, orientation, persistence and properties. Simulations are performed both in 2D for a single joint set to elucidate the basic response mechanisms, and in 3D for multiple joint sets to realistically represent in situ conditions in a realistic geologic setting. The joints are modeled explicitly using both contact elements and weakness planes in the material. Simulations are performed both deterministically and stochastically to quantify the effects of geologic uncertainties onmore » near field ground motions. The mechanical properties of the rock and the joints as well as the joint spacing and orientation are taken from experimental test data and geophysical logs corresponding to the Climax Stock granitic outcrop, which is the geologic setting of the Source Physics Experiment (SPE). Agreement between simulation results and near field wave motion data from SPE enables newfound understanding of the origin and extent of non-spherical motions associated with underground explosions in fractured geologic media.« less

Joint Oil Analysis Program Spectrometer Standards SCP Science (Conostan) Qualification Report for D19-0, D3-100, and D12-XXX Series Standards

DTIC Science & Technology

2015-05-20

Joint Oil Analysis Program Spectrometer Standards SCP Science (Conostan) Qualification Report For D19-0, D3-100, and D12- XXX Series Standards NF...Candidate Type D19-0 ICP-AES Results ..................................................................... 4 Table V. Candidate Type D12- XXX ...Physical Property Results .................................................. 5 Table VI. Candidate Type D12- XXX Rotrode-AES Results

3D strength surfaces for ankle plantar- and dorsi-flexion in healthy adults: an isometric and isokinetic dynamometry study.

PubMed

Hussain, Sara J; Frey-Law, Laura

2016-01-01

The ankle is an important component of the human kinetic chain, and deficits in ankle strength can negatively impact functional tasks such as balance and gait. While peak torque is influenced by joint angle and movement velocity, ankle strength is typically reported for a single angle or movement speed. To better identify deficits and track recovery of ankle strength after injury or surgical intervention, ankle strength across a range of movement velocities and joint angles in healthy adults is needed. Thus, the primary goals of this study were to generate a database of strength values and 3-dimensional strength surface models for plantarflexion (PF) and dorsiflexion (DF) ankle strength in healthy men and women. Secondary goals were to develop a means to estimate ankle strength percentiles as well as examine predictors of maximal ankle strength in healthy adults. Using an isokinetic dynamometer, we tested PF and DF peak torques at five joint angles (-10° [DF], 0° [neutral], 10° [PF], 20° [PF] and 30° [PF]) and six velocities (0°/s, 30°/s, 60°/s, 90°/s, 120°/s and 180°/s) in 53 healthy adults. These data were used to generate 3D plots, or "strength surfaces", for males and females for each direction; surfaces were fit using a logistic equation. We also tested predictors of ankle strength, including height, weight, sex, and self-reported physical activity levels. Torque-velocity and torque-angle relationships at the ankle interact, indicating that these relationships are interdependent and best modeled using 3D surfaces. Sex was the strongest predictor of ankle strength over height, weight, and self-reported physical activity levels. 79 to 97 % of the variance in mean peak torque was explained by joint angle and movement velocity using logistic equations, for men and women and PF and DF directions separately. The 3D strength data and surface models provide a more comprehensive dataset of ankle strength in healthy adults than previously reported. These models may allow researchers and clinicians to quantify ankle strength deficits and track recovery in patient populations, using angle- and velocity-specific ankle strength values and/or strength percentiles from healthy adults.

In Vivo Measurement of Glenohumeral Joint Contact Patterns

NASA Astrophysics Data System (ADS)

Bey, Michael J.; Kline, Stephanie K.; Zauel, Roger; Kolowich, Patricia A.; Lock, Terrence R.

2009-12-01

The objectives of this study were to describe a technique for measuring in-vivo glenohumeral joint contact patterns during dynamic activities and to demonstrate application of this technique. The experimental technique calculated joint contact patterns by combining CT-based 3D bone models with joint motion data that were accurately measured from biplane x-ray images. Joint contact patterns were calculated for the repaired and contralateral shoulders of 20 patients who had undergone rotator cuff repair. Significant differences in joint contact patterns were detected due to abduction angle and shoulder condition (i.e., repaired versus contralateral). Abduction angle had a significant effect on the superior/inferior contact center position, with the average joint contact center of the repaired shoulder 12.1% higher on the glenoid than the contralateral shoulder. This technique provides clinically relevant information by calculating in-vivo joint contact patterns during dynamic conditions and overcomes many limitations associated with conventional techniques for quantifying joint mechanics.

Accurate 3D reconstruction of bony surfaces using ultrasonic synthetic aperture techniques for robotic knee arthroplasty.

PubMed

Kerr, William; Rowe, Philip; Pierce, Stephen Gareth

2017-06-01

Robotically guided knee arthroplasty systems generally require an individualized, preoperative 3D model of the knee joint. This is typically measured using Computed Tomography (CT) which provides the required accuracy for preoperative surgical intervention planning. Ultrasound imaging presents an attractive alternative to CT, allowing for reductions in cost and the elimination of doses of ionizing radiation, whilst maintaining the accuracy of the 3D model reconstruction of the joint. Traditional phased array ultrasound imaging methods, however, are susceptible to poor resolution and signal to noise ratios (SNR). Alleviating these weaknesses by offering superior focusing power, synthetic aperture methods have been investigated extensively within ultrasonic non-destructive testing. Despite this, they have yet to be fully exploited in medical imaging. In this paper, the ability of a robotic deployed ultrasound imaging system based on synthetic aperture methods to accurately reconstruct bony surfaces is investigated. Employing the Total Focussing Method (TFM) and the Synthetic Aperture Focussing Technique (SAFT), two samples were imaged which were representative of the bones of the knee joint: a human-shaped, composite distal femur and a bovine distal femur. Data were captured using a 5MHz, 128 element 1D phased array, which was manipulated around the samples using a robotic positioning system. Three dimensional surface reconstructions were then produced and compared with reference models measured using a precision laser scanner. Mean errors of 0.82mm and 0.88mm were obtained for the composite and bovine samples, respectively, thus demonstrating the feasibility of the approach to deliver the sub-millimetre accuracy required for the application. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Quantitative power Doppler ultrasound measures of peripheral joint synovitis in poor prognosis early rheumatoid arthritis predict radiographic progression.

PubMed

Sreerangaiah, Dee; Grayer, Michael; Fisher, Benjamin A; Ho, Meilien; Abraham, Sonya; Taylor, Peter C

2016-01-01

To assess the value of quantitative vascular imaging by power Doppler US (PDUS) as a tool that can be used to stratify patient risk of joint damage in early seropositive RA while still biologic naive but on synthetic DMARD treatment. Eighty-five patients with seropositive RA of <3 years duration had clinical, laboratory and imaging assessments at 0 and 12 months. Imaging assessments consisted of radiographs of the hands and feet, two-dimensional (2D) high-frequency and PDUS imaging of 10 MCP joints that were scored for erosions and vascularity and three-dimensional (3D) PDUS of MCP joints and wrists that were scored for vascularity. Severe deterioration on radiographs and ultrasonography was seen in 45 and 28% of patients, respectively. The 3D power Doppler volume and 2D vascularity scores were the most useful US predictors of deterioration. These variables were modelled in two equations that estimate structural damage over 12 months. The equations had a sensitivity of 63.2% and specificity of 80.9% for predicting radiographic structural damage and a sensitivity of 54.2% and specificity of 96.7% for predicting structural damage on ultrasonography. In seropositive early RA, quantitative vascular imaging by PDUS has clinical utility in predicting which patients will derive benefit from early use of biologic therapy. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

[Changes in 25-hydroxyvitamin D3 level in children with Henoch-Schönlein purpura].

PubMed

Zhang, Yuan-Da; Dong, Qing-Wei; Li, Rong-Min; Ji, Chao-Yu; Chu, Yong-Tao; Ma, Lei; Zhang, Yu

2017-03-01

To examine the changes in 25-hydroxyvitamin D 3 [25-(OH)D 3 ] level in children with Henoch-Schönlein purpura (HSP) and its clinical significance. A total of 92 HSP children were included in this study, and were divided into HSP nephritis (HSPN) group (31 cases) and HSP group (61 cases) based on the presence or absence of HSPN. Alternatively, the patients were divided into purpura alone group (22 cases), purpura with joint symptoms group (joint symptom group, 24 cases), purpura with gastrointestinal symptoms group (gastrointestinal symptom group, 20 cases), and purpura with joint and gastrointestinal symptoms (mixed group, 26 cases) based on their clinical symptoms. In addition, 42 healthy children were selected as healthy control group. The level of 25-(OH)D 3 in each group was measured using enzyme-linked immunoassay. The 25-(OH)D 3 level in the HSP and HSPN groups was significantly lower than that in the healthy control group (P<0.05), and the 25-(OH)D 3 level in the HSPN group was significantly lower than that in the HSP group (P<0.05). Although there was no significant difference in the 25-(OH)D 3 level between the joint symptom, gastrointestinal symptom, and mixed groups (P=0.22), the 25-(OH)D 3 level in the three groups was all significantly lower than that in the purpura alone group (P<0.05). The level of 25-(OH)D 3 is reduced in children with HSP, particularly those with HSPN or with joint and gastrointestinal symptoms. Therefore, the reduction in 25-(OH)D 3 level may serve as a predictor of whether HSP is associated with other impairments.

CAD-Based Modeling of Advanced Rotary Wing Structures for Integrated 3-D Aeromechanics Analysis

NASA Astrophysics Data System (ADS)

Staruk, William

This dissertation describes the first comprehensive use of integrated 3-D aeromechanics modeling, defined as the coupling of 3-D solid finite element method (FEM) structural dynamics with 3-D computational fluid dynamics (CFD), for the analysis of a real helicopter rotor. The development of this new methodology (a departure from how rotor aeroelastic analysis has been performed for 40 years), its execution on a real rotor, and the fundamental understanding of aeromechanics gained from it, are the key contributions of this dissertation. This work also presents the first CFD/CSD analysis of a tiltrotor in edgewise flight, revealing many of its unique loading mechanisms. The use of 3-D FEM, integrated with a trim solver and aerodynamics modeling, has the potential to enhance the design of advanced rotors by overcoming fundamental limitations of current generation beam-based analysis tools and offering integrated internal dynamic stress and strain predictions for design. Two primary goals drove this research effort: 1) developing a methodology to create 3-D CAD-based brick finite element models of rotors including multibody joints, controls, and aerodynamic interfaces, and 2) refining X3D, the US Army's next generation rotor structural dynamics solver featuring 3-D FEM within a multibody formulation with integrated aerodynamics, to model a tiltrotor in the edgewise conversion flight regime, which drives critical proprotor structural loads. Prior tiltrotor analysis has primarily focused on hover aerodynamics with rigid blades or forward flight whirl-flutter stability with simplified aerodynamics. The first goal was met with the development of a detailed methodology for generating multibody 3-D structural models, starting from CAD geometry, continuing to higher-order hexahedral finite element meshing, to final assembly of the multibody model by creating joints, assigning material properties, and defining the aerodynamic interface. Several levels of verification and validation were carried out systematically, covering formulation, model accuracy, and accuracy of the physics of the problem and the many complex coupled aeromechanical phenomena that characterize the behavior of a tiltrotor in the conversion corridor. Compatibility of the new structural analysis models with X3D is demonstrated using analytical test cases, including 90° twisted beams and thick composite plates, and a notional bearingless rotor. Prediction of deformations and stresses in composite beams and plates is validated and verified against experimental measurements, theory, and state-of-the-art beam models. The second goal was met through integrated analysis of the Tilt Rotor Aeroacoustic Model (TRAM) proprotor using X3D coupled to Helios--the US Army's next generation CFD framework featuring a high fidelity Reynolds-average Navier-Stokes (RANS) structured/unstructured overset solver--as well as low order aerodynamic models. Although development of CFD was not part of this work, coupling X3D with Helios was, including establishing consistent interface definitions for blade deformations (for CFD mesh motion), aerodynamic interfaces (for loads transfer), and rotor control angles (for trim). It is expected that this method and solver will henceforth be an integral part of the Helios framework, providing an equal fidelity of representation for fluids and structures in the development of future advanced rotor systems. Structural dynamics analysis of the TRAM model show accurate prediction of the lower natural frequencies, demonstrating the ability to model advanced rotors from first principles using 3-D structural dynamics, and a study of how joint properties affect these frequencies reveals how X3D can be used as a detailed design tool. The CFD/CSD analysis reveals accurate prediction of rotor performance and airloads in edgewise flight when compared to wind tunnel test data. Structural blade loads trends are well predicted at low thrust, but a 3/rev component of flap and lag bending moment appearing in test data at high thrust remains a mystery. Efficiently simulating a gimbaled rotor is not trivial; a time-domain method with only a single blade model is proposed and tested. The internal stress in the blade, particularly at its root where the gimbal action has major influence, is carefully examined, revealing complex localized loading patterns.

Muscle function may depend on model selection in forward simulation of normal walking

PubMed Central

Xiao, Ming; Higginson, Jill S.

2008-01-01

The purpose of this study was to quantify how the predicted muscle function would change in a muscle-driven forward simulation of normal walking when changing the number of degrees of freedom in the model. Muscle function was described by individual muscle contributions to the vertical acceleration of the center of mass (COM). We built a two-dimensional (2D) sagittal plane model and a three-dimensional (3D) model in OpenSim and used both models to reproduce the same normal walking data. Perturbation analysis was applied to deduce muscle function in each model. Muscle excitations and contributions to COM support were compared between the 2D and 3D models. We found that the 2D model was able to reproduce similar joint kinematics and kinetics patterns as the 3D model. Individual muscle excitations were different for most of the hip muscles but ankle and knee muscles were able to attain similar excitations. Total induced vertical COM acceleration by muscles and gravity was the same for both models. However, individual muscle contributions to COM support varied, especially for hip muscles. Although there is currently no standard way to validate muscle function predictions, a 3D model seems to be more appropriate for estimating individual hip muscle function. PMID:18804767

Three-Dimensional Biomechanical Analysis of Rearfoot and Forefoot Running.

PubMed

Knorz, Sebastian; Kluge, Felix; Gelse, Kolja; Schulz-Drost, Stefan; Hotfiel, Thilo; Lochmann, Matthias; Eskofier, Björn; Krinner, Sebastian

2017-07-01

In the running community, a forefoot strike (FFS) pattern is increasingly preferred compared with a rearfoot strike (RFS) pattern. However, it has not been fully understood which strike pattern may better reduce adverse joint forces within the different joints of the lower extremity. To analyze the 3-dimensional (3D) stress pattern in the ankle, knee, and hip joint in runners with either a FFS or RFS pattern. Descriptive laboratory study. In 22 runners (11 habitual rearfoot strikers, 11 habitual forefoot strikers), RFS and FFS patterns were compared at 3.0 m/s (6.7 mph) on a treadmill with integrated force plates and a 3D motion capture analysis system. This combined analysis allowed characterization of the 3D biomechanical forces differentiated for the ankle, knee, and hip joint. The maximum peak force (MPF) and maximum loading rate (LR) were determined in their 3 ordinal components: vertical, anterior-posterior (AP), and medial-lateral (ML). For both strike patterns, the vertical components of the MPF and LR were significantly greater than their AP or ML components. In the vertical axis, FFS was generally associated with a greater MPF but significantly lower LR in all 3 joints. The AP components of MPF and LR were significantly lower for FFS in the knee joint but significantly greater in the ankle and hip joints. The ML components of MPF and LR tended to be greater for FFS but mostly did not reach a level of significance. FFS and RFS were associated with different 3D stress patterns in the ankle, knee, and hip joint, although there was no global advantage of one strike pattern over the other. The multimodal individual assessment for the different anatomic regions demonstrated that FFS seems favorable for patients with unstable knee joints in the AP axis and RFS may be recommended for runners with unstable ankle joints. Different strike patterns show different 3D stress in joints of the lower extremity. Due to either rehabilitation after injuries or training in running sports, rearfoot or forefoot running should be preferred to prevent further damage or injuries caused by inadequate biomechanical load. Runners with a history of knee joint injuries may benefit from FFS whereas RFS may be favorable for runners with a history of ankle joint injuries.

Three-Dimensional Biomechanical Analysis of Rearfoot and Forefoot Running

PubMed Central

Knorz, Sebastian; Kluge, Felix; Gelse, Kolja; Schulz-Drost, Stefan; Hotfiel, Thilo; Lochmann, Matthias; Eskofier, Björn; Krinner, Sebastian

2017-01-01

Background: In the running community, a forefoot strike (FFS) pattern is increasingly preferred compared with a rearfoot strike (RFS) pattern. However, it has not been fully understood which strike pattern may better reduce adverse joint forces within the different joints of the lower extremity. Purpose: To analyze the 3-dimensional (3D) stress pattern in the ankle, knee, and hip joint in runners with either a FFS or RFS pattern. Study Design: Descriptive laboratory study. Methods: In 22 runners (11 habitual rearfoot strikers, 11 habitual forefoot strikers), RFS and FFS patterns were compared at 3.0 m/s (6.7 mph) on a treadmill with integrated force plates and a 3D motion capture analysis system. This combined analysis allowed characterization of the 3D biomechanical forces differentiated for the ankle, knee, and hip joint. The maximum peak force (MPF) and maximum loading rate (LR) were determined in their 3 ordinal components: vertical, anterior-posterior (AP), and medial-lateral (ML). Results: For both strike patterns, the vertical components of the MPF and LR were significantly greater than their AP or ML components. In the vertical axis, FFS was generally associated with a greater MPF but significantly lower LR in all 3 joints. The AP components of MPF and LR were significantly lower for FFS in the knee joint but significantly greater in the ankle and hip joints. The ML components of MPF and LR tended to be greater for FFS but mostly did not reach a level of significance. Conclusion: FFS and RFS were associated with different 3D stress patterns in the ankle, knee, and hip joint, although there was no global advantage of one strike pattern over the other. The multimodal individual assessment for the different anatomic regions demonstrated that FFS seems favorable for patients with unstable knee joints in the AP axis and RFS may be recommended for runners with unstable ankle joints. Clinical Relevance: Different strike patterns show different 3D stress in joints of the lower extremity. Due to either rehabilitation after injuries or training in running sports, rearfoot or forefoot running should be preferred to prevent further damage or injuries caused by inadequate biomechanical load. Runners with a history of knee joint injuries may benefit from FFS whereas RFS may be favorable for runners with a history of ankle joint injuries. PMID:28812039

Accuracy assessment of 3D bone reconstructions using CT: an intro comparison.

PubMed

Lalone, Emily A; Willing, Ryan T; Shannon, Hannah L; King, Graham J W; Johnson, James A

2015-08-01

Computed tomography provides high contrast imaging of the joint anatomy and is used routinely to reconstruct 3D models of the osseous and cartilage geometry (CT arthrography) for use in the design of orthopedic implants, for computer assisted surgeries and computational dynamic and structural analysis. The objective of this study was to assess the accuracy of bone and cartilage surface model reconstructions by comparing reconstructed geometries with bone digitizations obtained using an optical tracking system. Bone surface digitizations obtained in this study determined the ground truth measure for the underlying geometry. We evaluated the use of a commercially available reconstruction technique using clinical CT scanning protocols using the elbow joint as an example of a surface with complex geometry. To assess the accuracies of the reconstructed models (8 fresh frozen cadaveric specimens) against the ground truth bony digitization-as defined by this study-proximity mapping was used to calculate residual error. The overall mean error was less than 0.4 mm in the cortical region and 0.3 mm in the subchondral region of the bone. Similarly creating 3D cartilage surface models from CT scans using air contrast had a mean error of less than 0.3 mm. Results from this study indicate that clinical CT scanning protocols and commonly used and commercially available reconstruction algorithms can create models which accurately represent the true geometry. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kitanidis, Peter

As large-scale, commercial storage projects become operational, the problem of utilizing information from diverse sources becomes more critically important. In this project, we developed, tested, and applied an advanced joint data inversion system for CO 2 storage modeling with large data sets for use in site characterization and real-time monitoring. Emphasis was on the development of advanced and efficient computational algorithms for joint inversion of hydro-geophysical data, coupled with state-of-the-art forward process simulations. The developed system consists of (1) inversion tools using characterization data, such as 3D seismic survey (amplitude images), borehole log and core data, as well as hydraulic,more » tracer and thermal tests before CO 2 injection, (2) joint inversion tools for updating the geologic model with the distribution of rock properties, thus reducing uncertainty, using hydro-geophysical monitoring data, and (3) highly efficient algorithms for directly solving the dense or sparse linear algebra systems derived from the joint inversion. The system combines methods from stochastic analysis, fast linear algebra, and high performance computing. The developed joint inversion tools have been tested through synthetic CO 2 storage examples.« less

Time And Temperature Dependent Micromechanical Properties Of Solder Joints For 3D-Package Integration

NASA Astrophysics Data System (ADS)

Roellig, Mike; Meier, Karsten; Metasch, Rene

2010-11-01

The recent development of 3D-integrated electronic packages is characterized by the need to increase the diversity of functions and to miniaturize. Currently many 3D-integration concepts are being developed and all of them demand new materials, new designs and new processing technologies. The combination of simulation and experimental investigation becomes increasingly accepted since simulations help to shorten the R&D cycle time and reduce costs. Numerical calculations like the Finite-Element-Method are strong tools to calculate stress conditions in electronic packages resulting from thermal strains due to the manufacturing process and environmental loads. It is essential for the application of numerical calculations that the material data is accurate and describes sufficiently the physical behaviour. The developed machine allows the measurement of time and temperature dependent micromechanical properties of solder joints. Solder joints, which are used to mechanically and electrically connect different packages, are physically measured as they leave the process. This allows accounting for process influences, which may change material properties. Additionally, joint sizes and metallurgical interactions between solder and under bump metallization can be respected by this particular measurement. The measurement allows the determination of material properties within a temperature range of 20° C-200° C. Further, the time dependent creep deformation can be measured within a strain-rate range of 10-31/s-10-81/s. Solder alloys based on Sn-Ag/Sn-Ag-Cu with additionally impurities and joint sizes down to O/ 200 μm were investigated. To finish the material characterization process the material model coefficient were extracted by FEM-Simulation to increase the accuracy of data.

Running in ostriches (Struthio camelus): three-dimensional joint axes alignment and joint kinematics.

PubMed

Rubenson, Jonas; Lloyd, David G; Besier, Thor F; Heliams, Denham B; Fournier, Paul A

2007-07-01

Although locomotor kinematics in walking and running birds have been examined in studies exploring many biological aspects of bipedalism, these studies have been largely limited to two-dimensional analyses. Incorporating a five-segment, 17 degree-of-freedom (d.f.) kinematic model of the ostrich hind limb developed from anatomical specimens, we quantified the three-dimensional (3-D) joint axis alignment and joint kinematics during running (at approximately 3.3 m s(-1)) in the largest avian biped, the ostrich. Our analysis revealed that the majority of the segment motion during running in the ostrich occurs in flexion/extension. Importantly, however, the alignment of the average flexion/extension helical axes of the knee and ankle are rotated externally to the direction of travel (37 degrees and 21 degrees , respectively) so that pure flexion and extension at the knee will act to adduct and adbuct the tibiotarsus relative to the plane of movement, and pure flexion and extension at the ankle will act to abduct and adduct the tarsometatarsus relative to the plane of movement. This feature of the limb anatomy appears to provide the major lateral (non-sagittal) displacement of the lower limb necessary for steering the swinging limb clear of the stance limb and replaces what would otherwise require greater adduction/abduction and/or internal/external rotation, allowing for less complex joints, musculoskeletal geometry and neuromuscular control. Significant rotation about the joints' non-flexion/extension axes nevertheless occurs over the running stride. In particular, hip abduction and knee internal/external and varus/valgus motion may further facilitate limb clearance during the swing phase, and substantial non-flexion/extension movement at the knee is also observed during stance. Measurement of 3-D segment and joint motion in birds will be aided by the use of functionally determined axes of rotation rather than assumed axes, proving important when interpreting the biomechanics and motor control of avian bipedalism.

Serpentine Robot Model and Gait Design Using Autodesk Inventor and Simulink SimMechanics

NASA Astrophysics Data System (ADS)

Daniel; Iman Alamsyah, Mohammad; Erwin; Tan, Sofyan

2014-03-01

The authors introduce gaits of a serpentine robot with linear expansion mechanism where the robot varies its length using joints with three degrees of freedom. The 3D model of the serpentine robot is drawed in Autocad Inventor® and exported to SimMechanics® for straighforward modeling of the kinematics. The gaits are important for robots designed to explore ruins of disasters where the working spaces are very tight. For maximum flexibility of the serpentine robot, we adopted a joint design with three parallel actuators, where the joint is capable of linear movement in the forward axis, and rotational movements around two other axes. The designed linear expansion gaits is calculated for forward movement when the robot is posing straight or turning laterally.

Deep convolutional neural network and 3D deformable approach for tissue segmentation in musculoskeletal magnetic resonance imaging.

PubMed

Liu, Fang; Zhou, Zhaoye; Jang, Hyungseok; Samsonov, Alexey; Zhao, Gengyan; Kijowski, Richard

2018-04-01

To describe and evaluate a new fully automated musculoskeletal tissue segmentation method using deep convolutional neural network (CNN) and three-dimensional (3D) simplex deformable modeling to improve the accuracy and efficiency of cartilage and bone segmentation within the knee joint. A fully automated segmentation pipeline was built by combining a semantic segmentation CNN and 3D simplex deformable modeling. A CNN technique called SegNet was applied as the core of the segmentation method to perform high resolution pixel-wise multi-class tissue classification. The 3D simplex deformable modeling refined the output from SegNet to preserve the overall shape and maintain a desirable smooth surface for musculoskeletal structure. The fully automated segmentation method was tested using a publicly available knee image data set to compare with currently used state-of-the-art segmentation methods. The fully automated method was also evaluated on two different data sets, which include morphological and quantitative MR images with different tissue contrasts. The proposed fully automated segmentation method provided good segmentation performance with segmentation accuracy superior to most of state-of-the-art methods in the publicly available knee image data set. The method also demonstrated versatile segmentation performance on both morphological and quantitative musculoskeletal MR images with different tissue contrasts and spatial resolutions. The study demonstrates that the combined CNN and 3D deformable modeling approach is useful for performing rapid and accurate cartilage and bone segmentation within the knee joint. The CNN has promising potential applications in musculoskeletal imaging. Magn Reson Med 79:2379-2391, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Effects of the implant design on peri-implant bone stress and abutment micromovement: three-dimensional finite element analysis of original computer-aided design models.

PubMed

Yamanishi, Yasufumi; Yamaguchi, Satoshi; Imazato, Satoshi; Nakano, Tamaki; Yatani, Hirofumi

2014-09-01

Occlusal overloading causes peri-implant bone resorption. Previous studies examined stress distribution in alveolar bone around commercial implants using three-dimensional (3D) finite element analysis. However, the commercial implants contained some different designs. The purpose of this study is to reveal the effect of the target design on peri-implant bone stress and abutment micromovement. Six 3D implant models were created for different implant-abutment joints: 1) internal joint model (IM); 2) external joint model (EM); 3) straight abutment (SA) shape; 4) tapered abutment (TA) shapes; 5) platform switching (PS) in the IM; and 6) modified TA neck design (reverse conical neck [RN]). A static load of 100 N was applied to the basal ridge surface of the abutment at a 45-degree oblique angle to the long axis of the implant. Both stress distribution in peri-implant bone and abutment micromovement in the SA and TA models were analyzed. Compressive stress concentrated on labial cortical bone and tensile stress on the palatal side in the EM and on the labial side in the IM. There was no difference in maximum principal stress distribution for SA and TA models. Tensile stress concentration was not apparent on labial cortical bone in the PS model (versus IM). Maximum principal stress concentrated more on peri-implant bone in the RN than in the TA model. The TA model exhibited less abutment micromovement than the SA model. This study reveals the effects of the design of specific components on peri-implant bone stress and abutment displacement after implant-supported single restoration in the anterior maxilla.

Design and clinical outcome of a novel 3D-printed prosthetic joint replacement for the human temporomandibular joint.

PubMed

Ackland, David; Robinson, Dale; Lee, Peter Vee Sin; Dimitroulis, George

2018-05-11

Stock prosthetic temporomandibular joint replacements come in limited sizes, and do not always encompass the joint anatomy that presents clinically. The aims of this study were twofold. Firstly, to design a personalized prosthetic total joint replacement for the treatment of a patient's end-stage temporomandibular joint osteoarthritis, to implant the prosthesis into the patient, and assess clinical outcome 12-months post-operatively; and secondly, to evaluate the influence of changes in prosthetic condyle geometry on implant load response during mastication. A 48-year-old female patient with Grade-5 osteoarthritis to the left temporomandibular joint was recruited, and a prosthesis developed to match the native temporomandibular joint anatomy. The prosthesis was 3D printed, sterilized and implanted into the patient, and pain and function measured 12-months post-operatively. The prosthesis load response during a chewing-bite and maximum-force bite was evaluated using a personalized multi-body musculoskeletal model. Simulations were performed after perturbing condyle thickness, neck length and head sphericity. Increases in prosthetic condyle neck length malaligned the mandible and perturbed temporomandibular joint force. Changes in condylar component thickness greatly influenced fixation screw stress response, while a more eccentric condylar head increased prosthetic joint-contact loading. Post-operatively, the prosthetic temporomandibular joint surgery reduced patient pain from 7/10 to 1/10 on a visual analog scale, and increased intercisal opening distance from 22 mm to 38 mm. This study demonstrates effectiveness of a personalized prosthesis that may ultimately be adapted to treat a wide-range of end-stage temporomandibular joint conditions, and highlights sensitivity of prosthesis load response to changes in condylar geometry. Copyright © 2018 Elsevier Ltd. All rights reserved.

25-Hydroxyvitamin D Concentration, Vitamin D Intake and Joint Symptoms in Postmenopausal Women

PubMed Central

Chlebowski, Rowan T.; Johnson, Karen C.; Lane, Dorothy; Pettinger, Mary; Kooperberg, Charles L.; Wactawski-Wende, Jean; Rohan, Tom; Jo O'Sullivan, Mary; Yasmeen, Shagufta; Hiatt, Robert A.; Shikany, James M.; Vitolins, Mara; Khandekar, Janu; Hubbell, F. Allan

2010-01-01

Introduction Low 25 hydroxyvitamin D (25(OH) D) concentrations have been associated with radiologic worsening of osteoarthritis in some reports. However, the results are mixed and few studies have evaluated associations between 25(OH) D concentrations and both total vitamin D intake and clinical joint symptoms. Study Design Cross-sectional analyses of information from a subset of 1993 postmenopausal women obtained at baseline entry in the Women's Health Initiative Calcium plus Vitamin D clinical trial. Main Outcome Measures 25(OH) D concentration, total vitamin D intake (diet plus supplements), presence and severity of joint pain and joint swelling. Results The 25(OH) D levels were commonly low with 53% having deficient (< 50 nmol/L) and only 17% having sufficient (> 72 nmol/L) levels. Joint pain (reported by 74%) and joint swelling (reported by 34%) were also commonly reported. 25(OH) D concentrations were modestly correlated with total vitamin D intake (R =0.29, P<0.0001); however, considerable variability in 25(OH) D concentrations for a given vitamin D intake was seen. In adjusted linear regression models, lower serum 25(OH) D concentrations were associated with higher average joint pain score (P=0.01 for trend) with differences most apparent in the lowest 25(OH) D levels sextile. Conclusions Relatively low 25(OH) D levels and a high frequency of joint symptoms were common in this population of postmenopausal women. Total vitamin D intake was only modestly associated with 25(OH) D. Low serum 25(OH) D concentrations were associated with higher joint pain scores. These findings can inform the design of future intervention trials. PMID:21093181

Velocity Structure of the Iran Region Using Seismic and Gravity Observations

NASA Astrophysics Data System (ADS)

Syracuse, E. M.; Maceira, M.; Phillips, W. S.; Begnaud, M. L.; Nippress, S. E. J.; Bergman, E.; Zhang, H.

2015-12-01

We present a 3D Vp and Vs model of Iran generated using a joint inversion of body wave travel times, Rayleigh wave dispersion curves, and high-wavenumber filtered Bouguer gravity observations. Our work has two main goals: 1) To better understand the tectonics of a prominent example of continental collision, and 2) To assess the improvements in earthquake location possible as a result of joint inversion. The body wave dataset is mainly derived from previous work on location calibration and includes the first-arrival P and S phases of 2500 earthquakes whose initial locations qualify as GT25 or better. The surface wave dataset consists of Rayleigh wave group velocity measurements for regional earthquakes, which are inverted for a suite of period-dependent Rayleigh wave velocity maps prior to inclusion in the joint inversion for body wave velocities. We use gravity anomalies derived from the global gravity model EGM2008. To avoid mapping broad, possibly dynamic features in the gravity field intovariations in density and body wave velocity, we apply a high-pass wavenumber filter to the gravity measurements. We use a simple, approximate relationship between density and velocity so that the three datasets may be combined in a single inversion. The final optimized 3D Vp and Vs model allows us to explore how multi-parameter tomography addresses crustal heterogeneities in areas of limited coverage and improves travel time predictions. We compare earthquake locations from our models to independent locations obtained from InSAR analysis to assess the improvement in locations derived in a joint-inversion model in comparison to those derived in a more traditional body-wave-only velocity model.

An anisotropic thermal-stress model for through-silicon via

NASA Astrophysics Data System (ADS)

Liu, Song; Shan, Guangbao

2018-02-01

A two-dimensional thermal-stress model of through-silicon via (TSV) is proposed considering the anisotropic elastic property of the silicon substrate. By using the complex variable approach, the distribution of thermal-stress in the substrate can be characterized more accurately. TCAD 3-D simulations are used to verify the model accuracy and well agree with analytical results (< ±5%). The proposed thermal-stress model can be integrated into stress-driven design flow for 3-D IC , leading to the more accurate timing analysis considering the thermal-stress effect. Project supported by the Aerospace Advanced Manufacturing Technology Research Joint Fund (No. U1537208).

Predictive Simulations of Neuromuscular Coordination and Joint-Contact Loading in Human Gait.

PubMed

Lin, Yi-Chung; Walter, Jonathan P; Pandy, Marcus G

2018-04-18

We implemented direct collocation on a full-body neuromusculoskeletal model to calculate muscle forces, ground reaction forces and knee contact loading simultaneously for one cycle of human gait. A data-tracking collocation problem was solved for walking at the normal speed to establish the practicality of incorporating a 3D model of articular contact and a model of foot-ground interaction explicitly in a dynamic optimization simulation. The data-tracking solution then was used as an initial guess to solve predictive collocation problems, where novel patterns of movement were generated for walking at slow and fast speeds, independent of experimental data. The data-tracking solutions accurately reproduced joint motion, ground forces and knee contact loads measured for two total knee arthroplasty patients walking at their preferred speeds. RMS errors in joint kinematics were < 2.0° for rotations and < 0.3 cm for translations while errors in the model-computed ground-reaction and knee-contact forces were < 0.07 BW and < 0.4 BW, respectively. The predictive solutions were also consistent with joint kinematics, ground forces, knee contact loads and muscle activation patterns measured for slow and fast walking. The results demonstrate the feasibility of performing computationally-efficient, predictive, dynamic optimization simulations of movement using full-body, muscle-actuated models with realistic representations of joint function.

Fast super-resolution estimation of DOA and DOD in bistatic MIMO Radar with off-grid targets

NASA Astrophysics Data System (ADS)

Zhang, Dong; Zhang, Yongshun; Zheng, Guimei; Feng, Cunqian; Tang, Jun

2018-05-01

In this paper, we focus on the problem of joint DOA and DOD estimation in Bistatic MIMO Radar using sparse reconstruction method. In traditional ways, we usually convert the 2D parameter estimation problem into 1D parameter estimation problem by Kronecker product which will enlarge the scale of the parameter estimation problem and bring more computational burden. Furthermore, it requires that the targets must fall on the predefined grids. In this paper, a 2D-off-grid model is built which can solve the grid mismatch problem of 2D parameters estimation. Then in order to solve the joint 2D sparse reconstruction problem directly and efficiently, three kinds of fast joint sparse matrix reconstruction methods are proposed which are Joint-2D-OMP algorithm, Joint-2D-SL0 algorithm and Joint-2D-SOONE algorithm. Simulation results demonstrate that our methods not only can improve the 2D parameter estimation accuracy but also reduce the computational complexity compared with the traditional Kronecker Compressed Sensing method.

VES/TEM 1D joint inversion by using Controlled Random Search (CRS) algorithm

NASA Astrophysics Data System (ADS)

Bortolozo, Cassiano Antonio; Porsani, Jorge Luís; Santos, Fernando Acácio Monteiro dos; Almeida, Emerson Rodrigo

2015-01-01

Electrical (DC) and Transient Electromagnetic (TEM) soundings are used in a great number of environmental, hydrological, and mining exploration studies. Usually, data interpretation is accomplished by individual 1D models resulting often in ambiguous models. This fact can be explained by the way as the two different methodologies sample the medium beneath surface. Vertical Electrical Sounding (VES) is good in marking resistive structures, while Transient Electromagnetic sounding (TEM) is very sensitive to conductive structures. Another difference is VES is better to detect shallow structures, while TEM soundings can reach deeper layers. A Matlab program for 1D joint inversion of VES and TEM soundings was developed aiming at exploring the best of both methods. The program uses CRS - Controlled Random Search - algorithm for both single and 1D joint inversions. Usually inversion programs use Marquadt type algorithms but for electrical and electromagnetic methods, these algorithms may find a local minimum or not converge. Initially, the algorithm was tested with synthetic data, and then it was used to invert experimental data from two places in Paraná sedimentary basin (Bebedouro and Pirassununga cities), both located in São Paulo State, Brazil. Geoelectric model obtained from VES and TEM data 1D joint inversion is similar to the real geological condition, and ambiguities were minimized. Results with synthetic and real data show that 1D VES/TEM joint inversion better recovers simulated models and shows a great potential in geological studies, especially in hydrogeological studies.

Development of a morphology-based modeling technique for tracking solid-body displacements: examining the reliability of a potential MRI-only approach for joint kinematics assessment.

PubMed

Mahato, Niladri K; Montuelle, Stephane; Cotton, John; Williams, Susan; Thomas, James; Clark, Brian

2016-05-18

Single or biplanar video radiography and Roentgen stereophotogrammetry (RSA) techniques used for the assessment of in-vivo joint kinematics involves application of ionizing radiation, which is a limitation for clinical research involving human subjects. To overcome this limitation, our long-term goal is to develop a magnetic resonance imaging (MRI)-only, three dimensional (3-D) modeling technique that permits dynamic imaging of joint motion in humans. Here, we present our initial findings, as well as reliability data, for an MRI-only protocol and modeling technique. We developed a morphology-based motion-analysis technique that uses MRI of custom-built solid-body objects to animate and quantify experimental displacements between them. The technique involved four major steps. First, the imaging volume was calibrated using a custom-built grid. Second, 3-D models were segmented from axial scans of two custom-built solid-body cubes. Third, these cubes were positioned at pre-determined relative displacements (translation and rotation) in the magnetic resonance coil and scanned with a T1 and a fast contrast-enhanced pulse sequences. The digital imaging and communications in medicine (DICOM) images were then processed for animation. The fourth step involved importing these processed images into an animation software, where they were displayed as background scenes. In the same step, 3-D models of the cubes were imported into the animation software, where the user manipulated the models to match their outlines in the scene (rotoscoping) and registered the models into an anatomical joint system. Measurements of displacements obtained from two different rotoscoping sessions were tested for reliability using coefficient of variations (CV), intraclass correlation coefficients (ICC), Bland-Altman plots, and Limits of Agreement analyses. Between-session reliability was high for both the T1 and the contrast-enhanced sequences. Specifically, the average CVs for translation were 4.31 % and 5.26 % for the two pulse sequences, respectively, while the ICCs were 0.99 for both. For rotation measures, the CVs were 3.19 % and 2.44 % for the two pulse sequences with the ICCs being 0.98 and 0.97, respectively. A novel biplanar imaging approach also yielded high reliability with mean CVs of 2.66 % and 3.39 % for translation in the x- and z-planes, respectively, and ICCs of 0.97 in both planes. This work provides basic proof-of-concept for a reliable marker-less non-ionizing-radiation-based quasi-dynamic motion quantification technique that can potentially be developed into a tool for real-time joint kinematics analysis.

Pyrido[2,3-d]pyrimidin-5-ones: A Novel Class of Antiinflammatory Macrophage Colony-Stimulating Factor-1 Receptor Inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Hui; Hutta, Daniel A.; Rinker, James M.

A series of pyrido[2,3-d]pyrimidin-5-ones has been synthesized and evaluated as inhibitors of the kinase domain of macrophage colony-stimulating factor-1 receptor (FMS). FMS inhibitors may be useful in treating rheumatoid arthritis and other chronic inflammatory diseases. Structure-based optimization of the lead amide analogue 10 led to hydroxamate analogue 37, which possessed excellent potency and an improved pharmacokinetic profile. During the chronic phase of streptococcal cell wall-induced arthritis in rats, compound 37 (10, 3, and 1 mg/kg) was highly effective at reversing established joint swelling. In an adjuvant-induced arthritis model in rats, 37 prevented joint swelling partially at 10 mg/kg. In thismore » model, osteoclastogenesis and bone erosion were prevented by low doses (1 or 0.33 mg/kg) that had minimal impact on inflammation. These data underscore the potential of FMS inhibitors to prevent erosions and reduce symptoms in rheumatoid arthritis.« less

Applicability of three-dimensional imaging techniques in fetal medicine*

PubMed Central

Werner Júnior, Heron; dos Santos, Jorge Lopes; Belmonte, Simone; Ribeiro, Gerson; Daltro, Pedro; Gasparetto, Emerson Leandro; Marchiori, Edson

2016-01-01

Objective To generate physical models of fetuses from images obtained with three-dimensional ultrasound (3D-US), magnetic resonance imaging (MRI), and, occasionally, computed tomography (CT), in order to guide additive manufacturing technology. Materials and Methods We used 3D-US images of 31 pregnant women, including 5 who were carrying twins. If abnormalities were detected by 3D-US, both MRI and in some cases CT scans were then immediately performed. The images were then exported to a workstation in DICOM format. A single observer performed slice-by-slice manual segmentation using a digital high resolution screen. Virtual 3D models were obtained from software that converts medical images into numerical models. Those models were then generated in physical form through the use of additive manufacturing techniques. Results Physical models based upon 3D-US, MRI, and CT images were successfully generated. The postnatal appearance of either the aborted fetus or the neonate closely resembled the physical models, particularly in cases of malformations. Conclusion The combined use of 3D-US, MRI, and CT could help improve our understanding of fetal anatomy. These three screening modalities can be used for educational purposes and as tools to enable parents to visualize their unborn baby. The images can be segmented and then applied, separately or jointly, in order to construct virtual and physical 3D models. PMID:27818540

Biomechanics of an orthosis-managed cranial cruciate ligament-deficient canine stifle joint predicted by use of a computer model.

PubMed

Bertocci, Gina E; Brown, Nathan P; Mich, Patrice M

2017-01-01

OBJECTIVE To evaluate effects of an orthosis on biomechanics of a cranial cruciate ligament (CrCL)-deficient canine stifle joint by use of a 3-D quasistatic rigid-body pelvic limb computer model simulating the stance phase of gait and to investigate influences of orthosis hinge stiffness (durometer). SAMPLE A previously developed computer simulation model for a healthy 33-kg 5-year-old neutered Golden Retriever. PROCEDURES A custom stifle joint orthosis was implemented in the CrCL-deficient pelvic limb computer simulation model. Ligament loads, relative tibial translation, and relative tibial rotation in the orthosis-stabilized stifle joint (baseline scenario; high-durometer hinge]) were determined and compared with values for CrCL-intact and CrCL-deficient stifle joints. Sensitivity analysis was conducted to evaluate the influence of orthosis hinge stiffness on model outcome measures. RESULTS The orthosis decreased loads placed on the caudal cruciate and lateral collateral ligaments and increased load placed on the medial collateral ligament, compared with loads for the CrCL-intact stifle joint. Ligament loads were decreased in the orthosis-managed CrCL-deficient stifle joint, compared with loads for the CrCL-deficient stifle joint. Relative tibial translation and rotation decreased but were not eliminated after orthosis management. Increased orthosis hinge stiffness reduced tibial translation and rotation, whereas decreased hinge stiffness increased internal tibial rotation, compared with values for the baseline scenario. CONCLUSIONS AND CLINICAL RELEVANCE Stifle joint biomechanics were improved following orthosis implementation, compared with biomechanics of the CrCL-deficient stifle joint. Orthosis hinge stiffness influenced stifle joint biomechanics. An orthosis may be a viable option to stabilize a CrCL-deficient canine stifle joint.

Cartilage Dysfunction in ALS Patients as Side Effect of Motion Loss: 3D Mechano-Electrochemical Computational Model

PubMed Central

Gaffney, Eamonn A.; Doblaré, Manuel

2014-01-01

Amyotrophic lateral sclerosis (ALS) is a debilitating motor neuron disease characterized by progressive weakness, muscle atrophy, and fasciculation. This fact results in a continuous degeneration and dysfunction of articular soft tissues. Specifically, cartilage is an avascular and nonneural connective tissue that allows smooth motion in diarthrodial joints. Due to the avascular nature of cartilage tissue, cells nutrition and by-product exchange are intermittently occurring during joint motions. Reduced mobility results in a change of proteoglycan density, osmotic pressure, and permeability of the tissue. This work aims to demonstrate the abnormal cartilage deformation in progressive immobilized articular cartilage for ALS patients. For this aim a novel 3D mechano-electrochemical model based on the triphasic theory for charged hydrated soft tissues is developed. ALS patient parameters such as tissue porosity, osmotic coefficient, and fixed anions were incorporated. Considering different mobility reduction of each phase of the disease, results predicted the degree of tissue degeneration and the reduction of its capacity for deformation. The present model can be a useful tool to predict the evolution of joints in ALS patients and the necessity of including specific cartilage protectors, drugs, or maintenance physical activities as part of the symptomatic treatment in amyotrophic lateral sclerosis. PMID:24991537

Modeling and Inversion of three-dimensional crustal structures beneath the Pyrenees and their foreland basins based upon geological, gravimetric and seismological data

NASA Astrophysics Data System (ADS)

Spangenberg, Hannah; Chevrot, Sébastien; Courrioux, Gabriel; Guillen, Antonio

2017-04-01

Our goal is to obtain a three-dimensional (3D) model of mass density and seismic velocities beneath the Pyrenees and their foreland basins (Aquitaine and Ebro basins), which accounts for all the geological and geophysical information available for that region. This model covers the whole mountain range going from the Atlantic Ocean to the Mediterranean Sea, and from the Iberian range to the Massif Central. The model is described by different units: the lower, middle, and upper crusts, the accretionary prism, and the consolidated and unconsolidated sediment layers. Furthermore, a sub-continental, serpentinized European mantle is introduced to describe the exhumed mantle bodies which are responsible for the positive Bouguer gravity anomalies in the western Pyrenees. We build a first 3D model using all the geological information: drill-hole surveys, seismic sections, and the geological map. We use the potential field method implemented in Geomodeler to interpolate these geological data. However, these data are too sparse to build a model that explains seismic travel times or gravimetric data, especially the Labourd and the St. Gaudens Bouguer gravity anomalies. In addition, inconsistencies between the different data sets exist. We thus add by trial and error additional data points, comparing modeled and observed Bouguer gravimetric anomalies. The result of this procedure is a 3D geological model that respects the geological data and explains the measured Bouguer gravimetric anomalies. In a second step, we use this model to determine the average density and seismic velocities inside each geological unit assuming uniform layers. To constrain the seismic velocities we use travel time picks extracted from the bulletin of the Pyrenean seismicity released by the Observatoire Midi Pyrenées. In a third step, we use this 3D a priori model in a Monte Carlo inversion to invert jointly gravimetric data and seismic travel times from the bulletin. This probabilistic approach yields detailed information about the sedimentary foreland basins and the crustal structures beneath the Pyrenees. We will present and discuss different key steps of the construction of the 3D model of the Pyrenees. We will also compare selected cross-sections extracted from this model to the ECORS profiles, as well as CCP stacks of receiver functions along several PYROPE transects. Keywords: Pyrenees, 3D modeling, gravity, seismic tomography, joint inversion

Three-dimensional and thermal surface imaging produces reliable measures of joint shape and temperature: a potential tool for quantifying arthritis

PubMed Central

Spalding, Steven J; Kwoh, C Kent; Boudreau, Robert; Enama, Joseph; Lunich, Julie; Huber, Daniel; Denes, Louis; Hirsch, Raphael

2008-01-01

Introduction The assessment of joints with active arthritis is a core component of widely used outcome measures. However, substantial variability exists within and across examiners in assessment of these active joint counts. Swelling and temperature changes, two qualities estimated during active joint counts, are amenable to quantification using noncontact digital imaging technologies. We sought to explore the ability of three dimensional (3D) and thermal imaging to reliably measure joint shape and temperature. Methods A Minolta 910 Vivid non-contact 3D laser scanner and a Meditherm med2000 Pro Infrared camera were used to create digital representations of wrist and metacarpalphalangeal (MCP) joints. Specialized software generated 3 quantitative measures for each joint region: 1) Volume; 2) Surface Distribution Index (SDI), a marker of joint shape representing the standard deviation of vertical distances from points on the skin surface to a fixed reference plane; 3) Heat Distribution Index (HDI), representing the standard error of temperatures. Seven wrists and 6 MCP regions from 5 subjects with arthritis were used to develop and validate 3D image acquisition and processing techniques. HDI values from 18 wrist and 9 MCP regions were obtained from 17 patients with active arthritis and compared to data from 10 wrist and MCP regions from 5 controls. Standard deviation (SD), coefficient of variation (CV), and intraclass correlation coefficients (ICC) were calculated for each quantitative measure to establish their reliability. CVs for volume and SDI were <1.3% and ICCs were greater than 0.99. Results Thermal measures were less reliable than 3D measures. However, significant differences were observed between control and arthritis HDI values. Two case studies of arthritic joints demonstrated quantifiable changes in swelling and temperature corresponding with changes in symptoms and physical exam findings. Conclusion 3D and thermal imaging provide reliable measures of joint volume, shape, and thermal patterns. Further refinement may lead to the use of these technologies to improve the assessment of disease activity in arthritis. PMID:18215307

Quantitative pre-clinical screening of therapeutics for joint diseases using contrast enhanced micro-computed tomography.

PubMed

Willett, N J; Thote, T; Hart, M; Moran, S; Guldberg, R E; Kamath, R V

2016-09-01

The development of effective therapies for cartilage protection has been limited by a lack of efficient quantitative cartilage imaging modalities in pre-clinical in vivo models. Our objectives were two-fold: first, to validate a new contrast-enhanced 3D imaging analysis technique, equilibrium partitioning of an ionic contrast agent-micro computed tomography (EPIC-μCT), in a rat medial meniscal transection (MMT) osteoarthritis (OA) model; and second, to quantitatively assess the sensitivity of EPIC-μCT to detect the effects of matrix metalloproteinase inhibitor (MMPi) therapy on cartilage degeneration. Rats underwent MMT surgery and tissues were harvested at 1, 2, and 3 weeks post-surgery or rats received an MMPi or vehicle treatment and tissues harvested 3 weeks post-surgery. Parameters of disease progression were evaluated using histopathology and EPIC-μCT. Correlations and power analyses were performed to compare the techniques. EPIC-μCT was shown to provide simultaneous 3D quantification of multiple parameters, including cartilage degeneration and osteophyte formation. In MMT animals treated with MMPi, OA progression was attenuated, as measured by 3D parameters such as lesion volume and osteophyte size. A post-hoc power analysis showed that 3D parameters for EPIC-μCT were more sensitive than 2D parameters requiring fewer animals to detect a therapeutic effect of MMPi. 2D parameters were comparable between EPIC-μCT and histopathology. This study demonstrated that EPIC-μCT has high sensitivity to provide 3D structural and compositional measurements of cartilage and bone in the joint. EPIC-μCT can be used in combination with histology to provide a comprehensive analysis to screen new potential therapies. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Distribution of joint local and total size and of extension for avalanches in the Brownian force model

NASA Astrophysics Data System (ADS)

Delorme, Mathieu; Le Doussal, Pierre; Wiese, Kay Jörg

2016-05-01

The Brownian force model is a mean-field model for local velocities during avalanches in elastic interfaces of internal space dimension d , driven in a random medium. It is exactly solvable via a nonlinear differential equation. We study avalanches following a kick, i.e., a step in the driving force. We first recall the calculation of the distributions of the global size (total swept area) and of the local jump size for an arbitrary kick amplitude. We extend this calculation to the joint density of local and global sizes within a single avalanche in the limit of an infinitesimal kick. When the interface is driven by a single point, we find new exponents τ0=5 /3 and τ =7 /4 , depending on whether the force or the displacement is imposed. We show that the extension of a "single avalanche" along one internal direction (i.e., the total length in d =1 ) is finite, and we calculate its distribution following either a local or a global kick. In all cases, it exhibits a divergence P (ℓ ) ˜ℓ-3 at small ℓ . Most of our results are tested in a numerical simulation in dimension d =1 .

Numerical analysis and experimental research of the rubber boot of the joint drive vehicle

NASA Astrophysics Data System (ADS)

Ziobro, Jan

2016-04-01

The article presents many numerical studies and experimental research of the drive rubber boot of the joint drive vehicle. Performance requirements have been discussed and the required coefficients of the mathematical model for numerical simulation have been determined. The behavior of living in MSC.MARC environment was examined. In the analysis the following have been used: hyperplastic two-parameter model of the Mooney-Rivlin material, large displacements procedure, safe contact condition, friction on the sides of the boots. 3D numerical model of the joint bootwas analyzed under influence of the forces: tensile, compressive, centrifugal and angular. Numerous results of studies have been presented. An appropriate test stand was built and comparison of the results of the numerical analysis and the results of experimental studies was made. Numerous requests and recommendations for utilitarian character have been presented.

An efficient sequential strategy for realizing cross-gradient joint inversion: method and its application to 2-D cross borehole seismic traveltime and DC resistivity tomography

NASA Astrophysics Data System (ADS)

Gao, Ji; Zhang, Haijiang

2018-05-01

Cross-gradient joint inversion that enforces structural similarity between different models has been widely utilized in jointly inverting different geophysical data types. However, it is a challenge to combine different geophysical inversion systems with the cross-gradient structural constraint into one joint inversion system because they may differ greatly in the model representation, forward modelling and inversion algorithm. Here we propose a new joint inversion strategy that can avoid this issue. Different models are separately inverted using the existing inversion packages and model structure similarity is only enforced through cross-gradient minimization between two models after each iteration. Although the data fitting and structural similarity enforcing processes are decoupled, our proposed strategy is still able to choose appropriate models to balance the trade-off between geophysical data fitting and structural similarity. This is realized by using model perturbations from separate data inversions to constrain the cross-gradient minimization process. We have tested this new strategy on 2-D cross borehole synthetic seismic traveltime and DC resistivity data sets. Compared to separate geophysical inversions, our proposed joint inversion strategy fits the separate data sets at comparable levels while at the same time resulting in a higher structural similarity between the velocity and resistivity models.

A Vision-Aided 3D Path Teaching Method before Narrow Butt Joint Welding

PubMed Central

Zeng, Jinle; Chang, Baohua; Du, Dong; Peng, Guodong; Chang, Shuhe; Hong, Yuxiang; Wang, Li; Shan, Jiguo

2017-01-01

For better welding quality, accurate path teaching for actuators must be achieved before welding. Due to machining errors, assembly errors, deformations, etc., the actual groove position may be different from the predetermined path. Therefore, it is significant to recognize the actual groove position using machine vision methods and perform an accurate path teaching process. However, during the teaching process of a narrow butt joint, the existing machine vision methods may fail because of poor adaptability, low resolution, and lack of 3D information. This paper proposes a 3D path teaching method for narrow butt joint welding. This method obtains two kinds of visual information nearly at the same time, namely 2D pixel coordinates of the groove in uniform lighting condition and 3D point cloud data of the workpiece surface in cross-line laser lighting condition. The 3D position and pose between the welding torch and groove can be calculated after information fusion. The image resolution can reach 12.5 μm. Experiments are carried out at an actuator speed of 2300 mm/min and groove width of less than 0.1 mm. The results show that this method is suitable for groove recognition before narrow butt joint welding and can be applied in path teaching fields of 3D complex components. PMID:28492481

A Vision-Aided 3D Path Teaching Method before Narrow Butt Joint Welding.

PubMed

Zeng, Jinle; Chang, Baohua; Du, Dong; Peng, Guodong; Chang, Shuhe; Hong, Yuxiang; Wang, Li; Shan, Jiguo

2017-05-11

For better welding quality, accurate path teaching for actuators must be achieved before welding. Due to machining errors, assembly errors, deformations, etc., the actual groove position may be different from the predetermined path. Therefore, it is significant to recognize the actual groove position using machine vision methods and perform an accurate path teaching process. However, during the teaching process of a narrow butt joint, the existing machine vision methods may fail because of poor adaptability, low resolution, and lack of 3D information. This paper proposes a 3D path teaching method for narrow butt joint welding. This method obtains two kinds of visual information nearly at the same time, namely 2D pixel coordinates of the groove in uniform lighting condition and 3D point cloud data of the workpiece surface in cross-line laser lighting condition. The 3D position and pose between the welding torch and groove can be calculated after information fusion. The image resolution can reach 12.5 μm. Experiments are carried out at an actuator speed of 2300 mm/min and groove width of less than 0.1 mm. The results show that this method is suitable for groove recognition before narrow butt joint welding and can be applied in path teaching fields of 3D complex components.

Lamb wave propagation in a restricted geometry composite pi-joint specimen

NASA Astrophysics Data System (ADS)

Blackshire, James L.; Soni, Som

2012-05-01

The propagation of elastic waves in a material can involve a number of complex physical phenomena, resulting in both subtle and dramatic effects on detected signal content. In recent years, the use of advanced methods for characterizing and imaging elastic wave propagation and scattering processes has increased, where for example the use of scanning laser vibrometry and advanced computational models have been used very effectively to identify propagating modes, scattering phenomena, and damage feature interactions. In the present effort, the propagation of Lamb waves within a narrow, constrained geometry composite pi-joint structure are studied using 3D finite element models and scanning laser vibrometry measurements, where the effects of varying sample thickness, complex joint curvatures, and restricted structure geometries are highlighted, and a direct comparison of computational and experimental results are provided for simulated and realistic geometry composite pi-joint samples.

“In vitro” Implantation Technique Based on 3D Printed Prosthetic Prototypes

NASA Astrophysics Data System (ADS)

Tarnita, D.; Boborelu, C.; Geonea, I.; Malciu, R.; Grigorie, L.; Tarnita, D. N.

2018-06-01

In this paper, Rapid Prototyping ZCorp 310 system, based on high-performance composite powder and on resin-high strength infiltration system and three-dimensional printing as a manufacturing method are used to obtain physical prototypes of orthopaedic implants and prototypes of complex functional prosthetic systems directly from the 3D CAD data. These prototypes are useful for in vitro experimental tests and measurements to optimize and obtain final physical prototypes. Using a new elbow prosthesis model prototype obtained by 3D printing, the surgical technique of implantation is established. Surgical implantation was performed on male corpse elbow joint.

Seismic Tomography of the Sacramento -- San Joaquin River Delta: Joint P-wave/Gravity and Ambient Noise Methods

NASA Astrophysics Data System (ADS)

Teel, Alexander C.

The Sacramento -- San Joaquin River Delta (SSJRD) is an area that has been identified as having high seismic hazard but has resolution gaps in the seismic velocity models of the area due to a scarcity of local seismic stations and earthquakes. I present new three-dimensional (3D) P-wave velocity (Vp) and S-wave velocity (Vs) models for the SSJRD which fill in the sampling gaps of previous studies. I have created a new 3D seismic velocity model for the SSJRD, addressing an identified need for higher resolution velocity models in the region, using a new joint gravity/body-wave tomography algorithm. I am able to fit gravity and arrival-time residuals jointly using an empirical density-velocity relationship to take advantage of existing gravity data in the region to help fill in the resolution gaps of previous velocity models in the area. I find that the method enhances the ability to resolve the relief of basin structure relative to seismic-only tomography at this location. I find the depth to the basement to be the greatest in the northwest portion of the SSJRD and that there is a plateau in the basement structure beneath the southeast portion of the SSJRD. From my findings I infer that the SSJRD may be prone to focusing effects and basin amplification of ground motion. A 3D, Vs model for the SSJRD and surrounding area was created using ambient noise tomography. The empirical Green's functions are in good agreement with published cross-correlations and match earthquake waveforms sharing similar paths. The group velocity and shear velocity maps are in good agreement with published regional scale models. The new model maps velocity values on a local scale and successfully recovers the basin structure beneath the Delta. From this Vs model I find the maximum depth of the basin to reach approximately 15 km with the Great Valley Ophiolite body rising to a depth of 10 km east of the SSJRD. We consider our basement-depth estimates from the Vp model to be more robust than from the Vs model.

3D Geological modelling - towards a European level infrastructure

NASA Astrophysics Data System (ADS)

Lee, Kathryn A.; van der Krogt, Rob; Busschers, Freek S.

2013-04-01

The joint European Geological Surveys are preparing the ground for a "European Geological Data Infrastructure" (EGDI), under the framework of the FP7-project EGDI-Scope. This scoping study, started in June 2012, for a pan-European e-Infrastructure is based on the successes of earlier joint projects including 'OneGeology-Europe' and aims to provide the backbone for serving interoperable, geological data currently held by European Geological Surveys. Also data from past, ongoing and future European projects will be incorporated. The scope will include an investigation of the functional and technical requirements for serving 3D geological models and will look to research the potential for providing a framework to integrate models at different scales, and form a structure for enabling the development of new and innovative model delivery mechanisms. The EGDI-scope project encourages pan-European inter-disciplinary collaboration between all European Geological Surveys. It aims to enhance emerging web based technologies that will facilitate the delivery of geological data to user communities involved in European policy making and international industry, but also to geoscientific research communities and the general public. Therefore, stakeholder input and communication is imperative to the success, as is the collaboration with all the Geological Surveys of Europe. The most important functional and technical requirements for delivery of such information at pan-European level will be derived from exchanges with relevant European stakeholder representatives and providers of geological data. For handling and delivering 3D geological model data the project will need to address a number of strategic issues: • Which are the most important issues and queries for the relevant stakeholders, requiring 3D geological models? How can this be translated to functional requirements for development and design of an integrated European application? • How to handle the very large differences in quality and scales with regard to 3D geological modelling in different European countries and regions, within a harmonized European framework? • How to handle the differences in model concepts and perceptions, especially with regard to the leading developers of 3D geological models within Europe? • How to handle differences between participating countries concerning relevant legal issues, governance, and funding models? With a primary focus on these issues, the EGDI-Scope study will provide a number of possible scenarios for delivery of 3D geological models and information within an integrated European application, including the most relevant technical, legal and organizational consequences.

Human body motion tracking based on quantum-inspired immune cloning algorithm

NASA Astrophysics Data System (ADS)

Han, Hong; Yue, Lichuan; Jiao, Licheng; Wu, Xing

2009-10-01

In a static monocular camera system, to gain a perfect 3D human body posture is a great challenge for Computer Vision technology now. This paper presented human postures recognition from video sequences using the Quantum-Inspired Immune Cloning Algorithm (QICA). The algorithm included three parts. Firstly, prior knowledge of human beings was used, the key joint points of human could be detected automatically from the human contours and skeletons which could be thinning from the contours; And due to the complexity of human movement, a forecasting mechanism of occlusion joint points was addressed to get optimum 2D key joint points of human body; And then pose estimation recovered by optimizing between the 2D projection of 3D human key joint points and 2D detection key joint points using QICA, which recovered the movement of human body perfectly, because this algorithm could acquire not only the global optimal solution, but the local optimal solution.

Simulation of light transport in arthritic- and non-arthritic human fingers

NASA Astrophysics Data System (ADS)

Milanic, Matija; Paluchowski, Lukasz A.; Randeberg, Lise L.

2014-03-01

Rheumatoid arthritis is a disease that frequently leads to joint destruction. It has high incidence rates worldwide, and the disease significantly reduces patient's quality of life due to pain, swelling and stiffness of the affected joints. Early diagnosis is necessary to improve course of the disease, therefore sensitive and accurate diagnostic tools are required. Optical imaging techniques have capability for early diagnosis and monitoring of arthritis. As compared to conventional diagnostic techniques optical technique is a noninvasive, noncontact and fast way of collecting diagnostic information. However, a realistic model of light transport in human joints is needed for understanding and developing of such optical diagnostic tools. The aim of this study is to develop a 3D numerical model of light transport in a human finger. The model will guide development of a hyperspectral imaging (HSI) diagnostic modality for arthritis in human fingers. The implemented human finger geometry is based on anatomical data. Optical data of finger tissues are adjusted to represent either an arthritic or an unaffected finger. The geometry and optical data serve as input into a 3D Monte Carlo method, which calculate diffuse reflectance, transmittance and absorbed energy distributions. The parameters of the model are optimized based on HIS-measurements of human fingers. The presented model serves as an important tool for understanding and development of HSI as an arthritis diagnostic modality. Yet, it can be applied to other optical techniques and finger diseases.

Foot mechanics during the first six years of independent walking.

PubMed

Samson, William; Dohin, Bruno; Desroches, Guillaume; Chaverot, Jean-Luc; Dumas, Raphaël; Cheze, Laurence

2011-04-29

Recognition of the changes during gait that occur normally as a part of growth is essential to prevent mislabeling those changes from adult gait as evidence of gait pathology. Currently, in the literature, the definition of a mature age for ankle joint dynamics is controversial (i.e., between 5 and 10 years). Moreover, the mature age of the metatarsophalangeal (MP) joint, which is essential for the functioning of the foot, has not been defined in the literature. Thus, the objective of the present study explored foot mechanics (ankle and MP joints) in young children to define a mature age of foot function. Forty-two healthy children between 1 and 6 years of age and eight adults were measured during gait. The ground reaction force (GRF), the MP and ankle joint angles, moments, powers, and 3D angles between the joint moment and the joint angular velocity vectors (3D angle α(M.ω)) were processed and compared between four age groups (2, 3.5, 5 and adults). Based on statistical analysis, the MP joint biomechanical parameters were similar between children (older than 2 years) and adults, hinting at a quick maturation of this joint mechanics. The ankle joint parameters and the GRFs (except for the frontal plane) showed an adult-like pattern in 5-year-old children. Some ankle joint parameters, such as the joint power and the 3D angle α(M.ω) still evolved significantly until 3.5 years. Based on these results, it would appear that foot maturation during gait is fully achieved at 5 years. Copyright © 2011 Elsevier Ltd. All rights reserved.

Intra-articular injection of collagenase induced experimental osteoarthritis of the lumbar facet joint in rats.

PubMed

Yeh, Tsu-Te; Wen, Zhi-Hong; Lee, Herng-Sheng; Lee, Chian-Her; Yang, Zhi; Jean, Yen-Hsuan; Wu, Shing-Sheng; Nimni, Marcel E; Han, Bo

2008-05-01

We aimed to establish an animal model to investigate primary osteoarthritis of the lumbar facet joints after collagenase injection in rats and its effects on chondrocyte apoptosis. We hypothesized that osteoarthritic-like changes would be induced by collagenase injection and that apoptosis of chondrocytes would increase. Collagenase (1, 10, or 50 U) or saline (control) was injected into the lumbar facet joints. The histology and histochemistry of cartilage, synovium, and subchondral bone were examined at 1, 3, and 6 weeks after surgery. Apoptotic cells induced by 1 U of collagenase were quantified using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Degeneration of the cartilage and changes to the synovium and subchondral bone were dependent on both the doses of collagenase and the time after surgery. There were significantly more apoptotic chondrocytes in collagenase-treated joints than in control (P < 0.001 at 1 and 3 weeks and P < 0.05 at 6 weeks). Thus, lumbar facet joints subjected to collagenase developed osteoarthritic-like changes that could be quantified and compared. This model provides a useful tool for further study on the effects of compounds that have the potential to inhibit enzyme-associated damage to cartilage.

Comparison of the effects of caudal pole hemi-meniscectomy and complete medial meniscectomy in the canine stifle joint.

PubMed

Johnson, K A; Francis, D J; Manley, P A; Chu, Q; Caterson, B

2004-08-01

To compare the effects of caudal pole hemi-meniscectomy (CPHM) and complete medial meniscectomy (MM), specifically with respect to development of secondary osteoarthritis, in the stifle joints of clinically normal dogs. 14 large-breed dogs. Unilateral CPHM (7 dogs) or MM (7) was performed, and the left stifle joints served as untreated control joints. Gait was assessed in all dogs before surgery and at 4, 8, 12, and 16 weeks postoperatively. After euthanasia, joints were evaluated grossly; Mankin cartilage scores, subchondral bone density assessment, and articular cartilage proteoglycan extraction and western blot analyses of 3B3(-) and 7D4 epitopes were performed. Weight distribution on control limbs exceeded that of treated limbs at 4 and 16 weeks after surgery in the CPHM group and at 4 and 8 weeks after surgery in the MM group; weight distribution was not significantly different between the 2 groups. After 16 weeks, incomplete meniscal regeneration and cartilage fibrillation on the medial aspect of the tibial plateau and medial femoral condyle were detected in treated joints in both groups. Mankin cartilage scores, subchondral bone density, and immunoexpression of 3B3(-) or 7D4 in articular cartilage in CPHM- or MM-treated joints were similar; 7D4 epitope concentration in synovial fluid was significantly greater in the MM-treated joints than in CPHM-treated joints. Overall severity of secondary osteoarthritis induced by CPHM and MM was similar. Investigation of 7D4 epitope concentration in synovial fluid suggested that CPHM was associated with less disruption of chondrocyte metabolism.

Joint inversion of apparent resistivity and seismic surface and body wave data

NASA Astrophysics Data System (ADS)

Garofalo, Flora; Sauvin, Guillaume; Valentina Socco, Laura; Lecomte, Isabelle

2013-04-01

A novel inversion algorithm has been implemented to jointly invert apparent resistivity curves from vertical electric soundings, surface wave dispersion curves, and P-wave travel times. The algorithm works in the case of laterally varying layered sites. Surface wave dispersion curves and P-wave travel times can be extracted from the same seismic dataset and apparent resistivity curves can be obtained from continuous vertical electric sounding acquisition. The inversion scheme is based on a series of local 1D layered models whose unknown parameters are thickness h, S-wave velocity Vs, P-wave velocity Vp, and Resistivity R of each layer. 1D models are linked to surface-wave dispersion curves and apparent resistivity curves through classical 1D forward modelling, while a 2D model is created by interpolating the 1D models and is linked to refracted P-wave hodograms. A priori information can be included in the inversion and a spatial regularization is introduced as a set of constraints between model parameters of adjacent models and layers. Both a priori information and regularization are weighted by covariance matrixes. We show the comparison of individual inversions and joint inversion for a synthetic dataset that presents smooth lateral variations. Performing individual inversions, the poor sensitivity to some model parameters leads to estimation errors up to 62.5 %, whereas for joint inversion the cooperation of different techniques reduces most of the model estimation errors below 5% with few exceptions up to 39 %, with an overall improvement. Even though the final model retrieved by joint inversion is internally consistent and more reliable, the analysis of the results evidences unacceptable values of Vp/Vs ratio for some layers, thus providing negative Poisson's ratio values. To further improve the inversion performances, an additional constraint is added imposing Poisson's ratio in the range 0-0.5. The final results are globally improved by the introduction of this constraint further reducing the maximum error to 30 %. The same test was performed on field data acquired in a landslide-prone area close by the town of Hvittingfoss, Norway. Seismic data were recorded on two 160-m long profiles in roll-along mode using a 5-kg sledgehammer as source and 24 4.5-Hz vertical geophones with 4-m separation. First-arrival travel times were picked at every shot locations and surface wave dispersion curves extracted at 8 locations for each profile. 2D resistivity measurements were carried out on the same profiles using Gradient and Dipole-Dipole arrays with 2-m electrode spacing. The apparent resistivity curves were extracted at the same location as for the dispersion curves. The data were subsequently jointly inverted and the resulting model compared to individual inversions. Although models from both, individual and joint inversions are consistent, the estimation error is smaller for joint inversion, and more especially for first-arrival travel times. The joint inversion exploits different sensitivities of the methods to model parameters and therefore mitigates solution nonuniqueness and the effects of intrinsic limitations of the different techniques. Moreover, it produces an internally consistent multi-parametric final model that can be profitably interpreted to provide a better understanding of subsurface properties.

[Finite element analysis on the effect of lateral wedge insole intervention on the contact characteristics of the subtalar joint].

PubMed

Zhou, En-Chang; Tang, Ping; Zhu, Chuan-Ying; Liu, Shi-Ming

2017-01-25

To establish a three-dimensional finite element model of the lower limb bones, and investigate the changes of the contact characteristics of the subtalar joint after using laterally wedge insole intervention. Using the reverse modeling technology, the lower limb bones of normal adult volunteers was scanned by CT. Mimics 10.0 and Geomagic Studio 6.0 software were used to reconstruct the 3D morphology of bones and external soft tissue of the feet. The laterally wedge insole was designed in ProE 5.0. And then all the models were imported into Hyperwork 10.0 and meshed, and given the material properties. The finite element analysis was carried out in ABAQUS 6.9. A three-dimensional finite element model of the lower extremity was established, which was consisted of 95 365 nodes and 246 238 elements. The contact area of the standing state of the lower joint was larger than that of the anterior middle joint surface. The peak stress was concentrated in the anterior lateral part of the posterior articular surface, and the average stress value was(3.85±1.03) MPa. Compared with the model of 0°, the contact area of the subtalar joint was reduced accordingly. There was a significant correlation between anterior middle joint | r |=0.964, P =0.008, and posterior articular | r |=0.978, P =0.002. The equivalent stress of 0° model distributed from(3.07±1.14) MPa to(3.85± 1.03) MPa, which had no statistically difference. Compared with the 0° model, the equivalent stress of the anterior and middle joint surfaces of the 8° model was significantly reduced( P <0.05), but the peak stress of the posterior articular surface was significantly increased( P <0.05). In the 12° model, the peak stress was sharply increased to(10.51±3.53) MPa. Compared with 8° model, there was no statistically difference( P <0.05). Although the peak stress was slightly increased in 16° model, but compared with 12° model, there was no statistically differences( P >0.05). Although a certain valgus can be obtained in subtalar by wearing LWI, the result comes at the cost of the stress concentration on posterior surface. Through this study, we can find that LWI with 8° tilt angle could provide appropriate valgus moment without causing excessive concentration. Therefore, in order to avoid secondary ankle complications, we should not increase the tilt angle blindly.

A 3D musculoskeletal model of the western lowland gorilla hind limb: moment arms and torque of the hip, knee and ankle.

PubMed

Goh, Colleen; Blanchard, Mary L; Crompton, Robin H; Gunther, Michael M; Macaulay, Sophie; Bates, Karl T

2017-10-01

Three-dimensional musculoskeletal models have become increasingly common for investigating muscle moment arms in studies of vertebrate locomotion. In this study we present the first musculoskeletal model of a western lowland gorilla hind limb. Moment arms of individual muscles around the hip, knee and ankle were compared with previously published data derived from the experimental tendon travel method. Considerable differences were found which we attribute to the different methodologies in this specific case. In this instance, we argue that our 3D model provides more accurate and reliable moment arm data than previously published data on the gorilla because our model incorporates more detailed consideration of the 3D geometry of muscles and the geometric constraints that exist on their lines-of-action about limb joints. Our new data have led us to revaluate the previous conclusion that muscle moment arms in the gorilla hind limb are optimised for locomotion with crouched or flexed limb postures. Furthermore, we found that bipedalism and terrestrial quadrupedalism coincided more regularly with higher moment arms and torque around the hip, knee and ankle than did vertical climbing. This indicates that the ability of a gorilla to walk bipedally is not restricted by musculoskeletal adaptations for quadrupedalism and vertical climbing, at least in terms of moment arms and torque about hind limb joints. © 2017 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.

Considerations on the Use of 3-D Geophysical Models to Predict Test Ban Monitoring Observables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, D B; Zucca, J J; McCallen, D B

2007-07-09

The use of 3-D geophysical models to predict nuclear test ban monitoring observables (phase travel times, amplitudes, dispersion, etc.) is widely anticipated to provide improvements in the basic seismic monitoring functions of detection, association, location, discrimination and yield estimation. A number of questions arise when contemplating a transition from 1-D, 2-D and 2.5-D models to constructing and using 3-D models, among them: (1) Can a 3-D geophysical model or a collection of 3-D models provide measurably improved predictions of seismic monitoring observables over existing 1-D models, or 2-D and 2 1/2-D models currently under development? (2) Is a single modelmore » that can predict all observables achievable, or must separate models be devised for each observable? How should joint inversion of disparate observable data be performed, if required? (3) What are the options for model representation? Are multi-resolution models essential? How does representation affect the accuracy and speed of observable predictions? (4) How should model uncertainty be estimated, represented and how should it be used? Are stochastic models desirable? (5) What data types should be used to construct the models? What quality control regime should be established? (6) How will 3-D models be used in operations? Will significant improvements in the basic monitoring functions result from the use of 3-D models? Will the calculation of observables through 3-D models be fast enough for real-time use or must a strategy of pre-computation be employed? (7) What are the theoretical limits to 3-D model development (resolution, uncertainty) and performance in predicting monitoring observables? How closely can those limits be approached with projected data availability, station distribution and inverse methods? (8) What priorities should be placed on the acquisition of event ground truth information, deployment of new stations, development of new inverse techniques, exploitation of large-scale computing and other activities in the pursuit of 3-D model development and use? In this paper, we examine what technical issues must be addressed to answer these questions. Although convened for a somewhat broader purpose, the June 2007 Workshop on Multi-resolution 3D Earth Models held in Berkeley, CA also touched on this topic. Results from the workshop are summarized in this paper.« less

Effect of postural changes on 3D joint angular velocity during starting block phase.

PubMed

Slawinski, Jean; Dumas, Raphaël; Cheze, Laurence; Ontanon, Guy; Miller, Christian; Mazure-Bonnefoy, Alice

2013-01-01

Few studies have focused on the effect of posture during sprint start. The aim of this study was to measure the effect of the modification of horizontal distance between the blocks during sprint start on three dimensional (3D) joint angular velocity. Nine trained sprinters started using three different starting positions (bunched, medium and elongated). They were equipped with 63 passive reflective markers, and an opto-electronic Motion Analysis system was used to collect the 3D marker trajectories. During the pushing phase on the blocks, norm of the joint angular velocity (NJAV), 3D Euler angular velocity (EAV) and pushing time on the blocks were calculated. The results demonstrated that the decrease of the block spacing induces an opposite effect on the angular velocity of joints of the lower and the upper limbs. The NJAV of the upper limbs is greater in the bunched start, whereas the NJAV of the lower limbs is smaller. The modifications of NJAV were due to a combination of the movement of the joints in the different degrees of freedom. The medium start seems to be the best compromise because it leads, in a short pushing time, to a combination of optimal joint velocities for upper and lower segments.

Performance evaluation of an automatic MGRF-based lung segmentation approach

NASA Astrophysics Data System (ADS)

Soliman, Ahmed; Khalifa, Fahmi; Alansary, Amir; Gimel'farb, Georgy; El-Baz, Ayman

2013-10-01

The segmentation of the lung tissues in chest Computed Tomography (CT) images is an important step for developing any Computer-Aided Diagnostic (CAD) system for lung cancer and other pulmonary diseases. In this paper, we introduce a new framework for validating the accuracy of our developed Joint Markov-Gibbs based lung segmentation approach using 3D realistic synthetic phantoms. These phantoms are created using a 3D Generalized Gauss-Markov Random Field (GGMRF) model of voxel intensities with pairwise interaction to model the 3D appearance of the lung tissues. Then, the appearance of the generated 3D phantoms is simulated based on iterative minimization of an energy function that is based on the learned 3D-GGMRF image model. These 3D realistic phantoms can be used to evaluate the performance of any lung segmentation approach. The performance of our segmentation approach is evaluated using three metrics, namely, the Dice Similarity Coefficient (DSC), the modified Hausdorff distance, and the Average Volume Difference (AVD) between our segmentation and the ground truth. Our approach achieves mean values of 0.994±0.003, 8.844±2.495 mm, and 0.784±0.912 mm3, for the DSC, Hausdorff distance, and the AVD, respectively.

Automation Tools for Finite Element Analysis of Adhesively Bonded Joints

NASA Technical Reports Server (NTRS)

Tahmasebi, Farhad; Brodeur, Stephen J. (Technical Monitor)

2002-01-01

This article presents two new automation creation tools that obtain stresses and strains (Shear and peel) in adhesively bonded joints. For a given adhesively bonded joint Finite Element model, in which the adhesive is characterised using springs, these automation tools read the corresponding input and output files, use the spring forces and deformations to obtain the adhesive stresses and strains, sort the stresses and strains in descending order, and generate plot files for 3D visualisation of the stress and strain fields. Grids (nodes) and elements can be numbered in any order that is convenient for the user. Using the automation tools, trade-off studies, which are needed for design of adhesively bonded joints, can be performed very quickly.

Global-scale Joint Body and Surface Wave Tomography with Vertical Transverse Isotropy for Seismic Monitoring Applications

NASA Astrophysics Data System (ADS)

Simmons, Nathan; Myers, Steve

2017-04-01

We continue to develop more advanced models of Earth's global seismic structure with specific focus on improving predictive capabilities for future seismic events. Our most recent version of the model combines high-quality P and S wave body wave travel times and surface-wave group and phase velocities into a joint (simultaneous) inversion process to tomographically image Earth's crust and mantle. The new model adds anisotropy (known as vertical transverse isotropy) to the model, which is necessitated by the addition of surface waves to the tomographic data set. Like previous versions of the model the new model consists of 59 surfaces and 1.6 million model nodes from the surface to the core-mantle boundary, overlaying a 1-D outer and inner core model. The model architecture is aspherical and we directly incorporate Earth's expected hydrostatic shape (ellipticity and mantle stretching). We also explicitly honor surface undulations including the Moho, several internal crustal units, and the upper mantle transition zone undulations as predicated by previous studies. The explicit Earth model design allows for accurate travel time computation using our unique 3-D ray tracing algorithms, capable of 3-D ray tracing more than 20 distinct seismic phases including crustal, regional, teleseismic, and core phases. Thus, we can now incorporate certain secondary (and sometimes exotic) phases into source location determination and other analyses. New work on model uncertainty quantification assesses the error covariance of the model, which when completed will enable calculation of path-specific estimates of uncertainty for travel times computed using our previous model (LLNL-G3D-JPS) which is available to the monitoring and broader research community and we encourage external evaluation and validation. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Spatial variation of fixed charge density in knee joint cartilage from sodium MRI - Implication on knee joint mechanics under static loading.

PubMed

Räsänen, Lasse P; Tanska, Petri; Mononen, Mika E; Lammentausta, Eveliina; Zbýň, Štefan; Venäläinen, Mikko S; Szomolanyi, Pavol; van Donkelaar, Corrinus C; Jurvelin, Jukka S; Trattnig, Siegfried; Nieminen, Miika T; Korhonen, Rami K

2016-10-03

The effects of fixed charge density (FCD) and cartilage swelling have not been demonstrated on cartilage mechanics on knee joint level before. In this study, we present how the spatial and local variations of FCD affects the mechanical response of the knee joint cartilage during standing (half of the body weight, 13 minutes) using finite element (FE) modeling. The FCD distribution of tibial cartilage of an asymptomatic subject was determined using sodium ( 23 Na) MRI at 7T and implemented into a 3-D FE-model of the knee joint (Subject-specific model, FCD: 0.18±0.08 mEq/ml). Tissue deformation in the Subject-specific model was validated against experimental, in vivo loading of the joint conducted with a MR-compatible compression device. For comparison, models with homogeneous FCD distribution (homogeneous model) and FCD distribution obtained from literature (literature model) were created. Immediately after application of the load (dynamic response), the variations in FCD had minor effects on cartilage stresses and strains. After 13 minutes of standing, the spatial and local variations in FCD had most influence on axial strains. In the superficial tibial cartilage in the Subject-specific model, axial strains were increased up to +13% due to smaller FCD (mean -11%), as compared to the homogeneous model. Compared to the literature model, those were decreased up to -18% due to greater FCD (mean +7%). The findings demonstrate that the spatial and local FCD variations in cartilage modulates strains in knee joint cartilage. Thereby, the results highlight the mechanical importance of site-specific content of proteoglycans in cartilage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Data assimilation of ground GPG total electron content into a physics-based ionosheric model by use of the Kalman filter

NASA Technical Reports Server (NTRS)

Hajj, G. A.; Wilson, B. D.; Wang, C.; Pi, X.; Rosen, I. G.

2004-01-01

A three-dimensional (3-D) Global Assimilative Ionospheric Model (GAIM) is currently being developed by a joint University of Southern California and Jet Propulsion Laboratory (JPL) team. To estimate the electron density on a global grid, GAIM uses a first-principles ionospheric physics model and the Kalman filter as one of its possible estimation techniques.

Thermo-Mechanical Characterization of Friction Stir Spot Welded AA7050 Sheets by Means of Experimental and FEM Analyses

PubMed Central

D’Urso, Gianluca; Giardini, Claudio

2016-01-01

The present study was carried out to evaluate how the friction stir spot welding (FSSW) process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. The experimental study was performed by means of a CNC machine tool obtaining FSSW lap joints on AA7050 aluminum alloy plates. Three thermocouples were inserted into the samples to measure the temperatures at different distance from the joint axis during the whole FSSW process. Experiments was repeated varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the tests using a piezoelectric load cell, while the mechanical properties of the joints were evaluated by executing shear tests on the specimens. The correlation found between process parameters and joints properties, allowed to identify the best technological window. The data collected during the experiments were used to validate a simulation model of the FSSW process, too. The model was set up using a 2D approach for the simulation of a 3D problem, in order to guarantee a very simple and practical solution for achieving results in a very short time. A specific external routine for the calculation of the thermal energy due to friction acting between pin and sheet was developed. An index for the prediction of the joint mechanical properties using the FEM simulations was finally presented and validated. PMID:28773810

Thermo-Mechanical Characterization of Friction Stir Spot Welded AA7050 Sheets by Means of Experimental and FEM Analyses.

PubMed

D'Urso, Gianluca; Giardini, Claudio

2016-08-11

The present study was carried out to evaluate how the friction stir spot welding (FSSW) process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. The experimental study was performed by means of a CNC machine tool obtaining FSSW lap joints on AA7050 aluminum alloy plates. Three thermocouples were inserted into the samples to measure the temperatures at different distance from the joint axis during the whole FSSW process. Experiments was repeated varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the tests using a piezoelectric load cell, while the mechanical properties of the joints were evaluated by executing shear tests on the specimens. The correlation found between process parameters and joints properties, allowed to identify the best technological window. The data collected during the experiments were used to validate a simulation model of the FSSW process, too. The model was set up using a 2D approach for the simulation of a 3D problem, in order to guarantee a very simple and practical solution for achieving results in a very short time. A specific external routine for the calculation of the thermal energy due to friction acting between pin and sheet was developed. An index for the prediction of the joint mechanical properties using the FEM simulations was finally presented and validated.

A 3D joint interpretation of magnetotelluric and seismic tomographic models: The case of the volcanic island of Tenerife

NASA Astrophysics Data System (ADS)

García-Yeguas, Araceli; Ledo, Juanjo; Piña-Varas, Perla; Prudencio, Janire; Queralt, Pilar; Marcuello, Alex; Ibañez, Jesús M.; Benjumea, Beatriz; Sánchez-Alzola, Alberto; Pérez, Nemesio

2017-12-01

In this work we have done a 3D joint interpretation of magnetotelluric and seismic tomography models. Previously we have described different techniques to infer the inner structure of the Earth. We have focused on volcanic regions, specifically on Tenerife Island volcano (Canary Islands, Spain). In this area, magnetotelluric and seismic tomography studies have been done separately. The novelty of the present work is the combination of both techniques in Tenerife Island. For this aim we have applied Fuzzy Clusters Method at different depths obtaining several clusters or classes. From the results, a geothermal system has been inferred below Teide volcano, in the center of Tenerife Island. An edifice hydrothermally altered and full of fluids is situated below Teide, ending at 600 m below sea level. From this depth the resistivity and VP values increase downwards. We also observe a clay cap structure, a typical feature in geothermal systems related with low resistivity and low VP values.

Measurement of complex joint trajectories using slice-to-volume 2D/3D registration and cine MR

NASA Astrophysics Data System (ADS)

Bloch, C.; Figl, M.; Gendrin, C.; Weber, C.; Unger, E.; Aldrian, S.; Birkfellner, W.

2010-02-01

A method for studying the in vivo kinematics of complex joints is presented. It is based on automatic fusion of single slice cine MR images capturing the dynamics and a static MR volume. With the joint at rest the 3D scan is taken. In the data the anatomical compartments are identified and segmented resulting in a 3D volume of each individual part. In each of the cine MR images the joint parts are segmented and their pose and position are derived using a 2D/3D slice-to-volume registration to the volumes. The method is tested on the carpal joint because of its complexity and the small but complex motion of its compartments. For a first study a human cadaver hand was scanned and the method was evaluated with artificially generated slice images. Starting from random initial positions of about 5 mm translational and 12° rotational deviation, 70 to 90 % of the registrations converged successfully to a deviation better than 0.5 mm and 5°. First evaluations using real data from a cine MR were promising. The feasibility of the method was demonstrated. However we experienced difficulties with the segmentation of the cine MR images. We therefore plan to examine different parameters for the image acquisition in future studies.

Stresses in Solder Joints of Electronic Packages

DTIC Science & Technology

1991-12-31

soldering process. The device is soldered to the circuit board at a temperature of +185zc and this tempature is assumed to propagate only to the lead wire...tri-material assembly, showing the notation used hereafter, is shown in Figure 7. The Suhir model is applicable to assemblies with continuous...therefore the radii of curvature of layers are all equal. Using equilibrium equation (7) and moment-curvature equation (9) yields ()D D Xp (x) D T() -m 3 x

2D and 3D Modeling of the Stratigraphic Sequences at the Adriatic and Rhone Continental Margins

DTIC Science & Technology

2005-09-30

Grenerczy, D. Medak, S. Stein, and J. C. Weber (Eds.). The Adria Microplate : GPS Geodesy, Tectonics , and Hazards. Kluwer Academic Publisher, pp. 93-116... tectonics , and their influences on sequence architecture. John Swenson, with assistance from Chris Paola, Juan Fedele, myself and others have jointly...exploration of the margin’s response to variations in sea level, sediment supply, tectonic subsidence, and wave climate over longer timescales. I am

A personalized 3D-printed prosthetic joint replacement for the human temporomandibular joint: From implant design to implantation.

PubMed

Ackland, David C; Robinson, Dale; Redhead, Michael; Lee, Peter Vee Sin; Moskaljuk, Adrian; Dimitroulis, George

2017-05-01

Personalized prosthetic joint replacements have important applications in cases of complex bone and joint conditions where the shape and size of off-the-shelf components may not be adequate. The objective of this study was to design, test and fabricate a personalized 3D-printed prosthesis for a patient requiring total joint replacement surgery of the temporomandibular joint (TMJ). The new 'Melbourne' prosthetic TMJ design featured a condylar component sized specifically to the patient and fixation screw positions that avoid potential intra-operative damage to the mandibular nerve. The Melbourne prosthetic TMJ was developed for a 58-year-old female recipient with end-stage osteoarthritis of the TMJ. The load response of the prosthesis during chewing and a maximum-force bite was quantified using a personalized musculoskeletal model of the patient's masticatory system developed using medical images. The simulations were then repeated after implantation of the Biomet Microfixation prosthetic TMJ, an established stock device. The maximum condylar stresses, screw stress and mandibular stress at the screw-bone interface were lower in the Melbourne prosthetic TMJ (259.6MPa, 312.9MPa and 198.4MPa, respectively) than those in the Biomet Microfixation device (284.0MPa, 416.0MPa and 262.2MPa, respectively) during the maximum-force bite, with similar trends also observed during the chewing bite. After trialing surgical placement and evaluating prosthetic TMJ stability using cadaveric specimens, the prosthesis was fabricated using 3D printing, sterilized, and implanted into the female recipient. Six months post-operatively, the prosthesis recipient had a normal jaw opening distance (40.0 mm), with no complications identified. The new design features and immediate load response of the Melbourne prosthetic TMJ suggests that it may provide improved clinical and biomechanical joint function compared to a commonly used stock device, and reduce risk of intra-operative nerve damage during placement. The framework presented may be useful for designing and testing customized devices for the treatment of debilitating bone and joint conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fat-suppressed three-dimensional fast spoiled gradient-recalled echo imaging: a modified FS 3D SPGR technique for assessment of patellofemoral joint chondromalacia.

PubMed

Wang, S F; Cheng, H C; Chang, C Y

1999-01-01

Fast fat-suppressed (FS) three-dimensional (3D) spoiled gradient-recalled echo (SPGR) imaging of 64 articular cartilage regions in 16 patellofemoral joints was evaluated to assess its feasibility in diagnosing patellofemoral chondromalacia. It demonstrated good correlation with arthroscopic reports and took about half of the examination time that FS 3D SPGR did. This modified, faster technique has the potential to diagnose patellofemoral chondromalacia with shorter examination time than FS 3D SPGR did.

Visualization of stereoscopic anatomic models of the paranasal sinuses and cervical vertebrae from the surgical and procedural perspective.

PubMed

Chen, Jian; Smith, Andrew D; Khan, Majid A; Sinning, Allan R; Conway, Marianne L; Cui, Dongmei

2017-11-01

Recent improvements in three-dimensional (3D) virtual modeling software allows anatomists to generate high-resolution, visually appealing, colored, anatomical 3D models from computed tomography (CT) images. In this study, high-resolution CT images of a cadaver were used to develop clinically relevant anatomic models including facial skull, nasal cavity, septum, turbinates, paranasal sinuses, optic nerve, pituitary gland, carotid artery, cervical vertebrae, atlanto-axial joint, cervical spinal cord, cervical nerve root, and vertebral artery that can be used to teach clinical trainees (students, residents, and fellows) approaches for trans-sphenoidal pituitary surgery and cervical spine injection procedure. Volume, surface rendering and a new rendering technique, semi-auto-combined, were applied in the study. These models enable visualization, manipulation, and interaction on a computer and can be presented in a stereoscopic 3D virtual environment, which makes users feel as if they are inside the model. Anat Sci Educ 10: 598-606. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.

In vitro quantification of the performance of model-based mono-planar and bi-planar fluoroscopy for 3D joint kinematics estimation.

PubMed

Tersi, Luca; Barré, Arnaud; Fantozzi, Silvia; Stagni, Rita

2013-03-01

Model-based mono-planar and bi-planar 3D fluoroscopy methods can quantify intact joints kinematics with performance/cost trade-off. The aim of this study was to compare the performances of mono- and bi-planar setups to a marker-based gold-standard, during dynamic phantom knee acquisitions. Absolute pose errors for in-plane parameters were lower than 0.6 mm or 0.6° for both mono- and bi-planar setups. Mono-planar setups resulted critical in quantifying the out-of-plane translation (error < 6.5 mm), and bi-planar in quantifying the rotation along bone longitudinal axis (error < 1.3°). These errors propagated to joint angles and translations differently depending on the alignment of the anatomical axes and the fluoroscopic reference frames. Internal-external rotation was the least accurate angle both with mono- (error < 4.4°) and bi-planar (error < 1.7°) setups, due to bone longitudinal symmetries. Results highlighted that accuracy for mono-planar in-plane pose parameters is comparable to bi-planar, but with halved computational costs, halved segmentation time and halved ionizing radiation dose. Bi-planar analysis better compensated for the out-of-plane uncertainty that is differently propagated to relative kinematics depending on the setup. To take its full benefits, the motion task to be investigated should be designed to maintain the joint inside the visible volume introducing constraints with respect to mono-planar analysis.

Effect of Joint Scale and Processing on the Fracture of Sn-3Ag-0.5Cu Solder Joints: Application to Micro-bumps in 3D Packages

NASA Astrophysics Data System (ADS)

Talebanpour, B.; Huang, Z.; Chen, Z.; Dutta, I.

2016-01-01

In 3-dimensional (3D) packages, a stack of dies is vertically connected to each other using through-silicon vias and very thin solder micro-bumps. The thinness of the micro-bumps results in joints with a very high volumetric proportion of intermetallic compounds (IMCs), rendering them much more brittle compared to conventional joints. Because of this, the reliability of micro-bumps, and the dependence thereof on the proportion of IMC in the joint, is of substantial concern. In this paper, the growth kinetics of IMCs in thin Sn-3Ag-0.5Cu joints attached to Cu substrates were analyzed, and empirical kinetic laws for the growth of Cu6Sn5 and Cu3Sn in thin joints were obtained. Modified compact mixed mode fracture mechanics samples, with adhesive solder joints between massive Cu substrates, having similar thickness and IMC content as actual micro-bumps, were produced. The effects of IMC proportion and strain rate on fracture toughness and mechanisms were investigated. It was found that the fracture toughness G C decreased with decreasing joint thickness ( h Joint). In addition, the fracture toughness decreased with increasing strain rate. Aging also promoted alternation of the crack path between the two joint-substrate interfaces, possibly proffering a mechanism to enhance fracture toughness.

Measuring Femoral Torsion In Vivo Using Freehand 3-D Ultrasound Imaging.

PubMed

Passmore, Elyse; Pandy, Marcus G; Graham, H Kerr; Sangeux, Morgan

2016-02-01

Despite variation in bone geometry, muscle and joint function is often investigated using generic musculoskeletal models. Patient-specific bone geometry can be obtained from computerised tomography, which involves ionising radiation, or magnetic resonance imaging (MRI), which is costly and time consuming. Freehand 3-D ultrasound provides an alternative to obtain bony geometry. The purpose of this study was to determine the accuracy and repeatability of 3-D ultrasound in measuring femoral torsion. Measurements of femoral torsion were performed on 10 healthy adults using MRI and 3-D ultrasound. Measurements of femoral torsion from 3-D ultrasound were, on average, smaller than those from MRI (mean difference = 1.8°; 95% confidence interval: -3.9°, 7.5°). MRI and 3-D ultrasound had Bland and Altman repeatability coefficients of 3.1° and 3.7°, respectively. Accurate measurements of femoral torsion were obtained with 3-D ultrasound offering the potential to acquire patient-specific bone geometry for musculoskeletal modelling. Three-dimensional ultrasound is non-invasive and relatively inexpensive and can be integrated into gait analysis. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Fracture analysis of an Eocene reservoir in Eastern Tunisia by coupling Terrestrial Laser Scanning with GigaPan Technology and seismic attribute

NASA Astrophysics Data System (ADS)

Mastouri, Raja; Guerin, Antoine; Marchant, Robin; Derron, Marc-Henri; Boulares, Achref; Lazzez, Marzouk; Marillier, François; Jaboyedoff, Michel; Bouaziz, Samir

2015-04-01

It is usually not possible to study in situ fractures and faults of oil reservoirs. Then outcropping reservoir analogues are used instead. For this purpose, Terrestrial Laser Scanning (TLS) has been increasingly used for some years in the petroleum sector. The formations El Garia and Reineche make the Eocene oil reservoir of Eastern Tunisia. The fracturing of these formations has been analyzed on the surface by TLS on a reservoir analogue outcrop and in the depth by 3D seismic data. TLS datasets provide clear information on fracture geometry distribution (spacing and persistence), connectivity and joint orientation. These results were then compared to structures observed in depth with seismic data. The reservoir analogues are the Ousselat cliff (formation El Garia) and the Damous quarry (formation Reineche). Those two sites are made of marine limestone rich in large foraminifers, gastropods and nummulites. Fieldwork, TLS acquisitions and high-resolution GigaPan panoramas were put together to create digital outcrop models. A total of 9 scans at 3 different survey positions were carried out. Firstly, the data processing (cleaning, alignment and georeferencing of the raw point clouds) was carried out using the Polyworks software. Secondly, we draped Gigapixel pictures on the triangular mesh generated with 3DReshaper to produce relief shading. This process produces a photorealistic model that gives a 3D representation of the outcrop. Finally, Coltop3D was used to identify the different sets of discontinuities and to measure their orientations. Furthermore, we used some 3D seismic attribute data to interpret approximately 60 fractures and faults at the top of the Eocene reservoir. The Coltop3D analysis of the Ousselat cliff shows 5 sets of joints and fractures, with different dips and dip directions. They all strike in directions NW-SE, NNE-SSW, NE-SW and ENE-WSW. Using the photorealistic model, we measured approximately 120 fracture spacings ranging from 1.75m to 10m. For Reineche formation outcrop, the structural analog indicates 8 sets of joints and fractures. In Total, we measured 150 fracture spacings. The most part of fracture spacings range from 0.05m to 1m. The results show that many joints of the quarry rocks are interconnected with other small-scale fractures. The comparison between the stereonets obtained by Coltop3D and the seismic attributes indicated that fractures striking NW-SE to NNW-SSE and NE-SW to NNE-SSW are represented in all surveys position. The majority of the faults and fractures observed in TLS data and 3D seismic data can be explained by a combination of extension and shear. Moreover, in this study, we found that there is no correlation between fractures density or fracture distribution and lithology. Finally, the density and the geometry of the fractures have been also interpreted at the outcrop level and in depth, this comparison allows to better characterize the relationship between permeability, secondary porosity and fracture density of the Eocene reservoir.

Cold Flow Determination of the Internal Flow Environment Around the Submerged TVC Nozzle for the Space Shuttle SRM

NASA Technical Reports Server (NTRS)

Whitesides, R. H.; Ghosh, A.; Jenkins, S. L.; Bacchus, D. L.

1989-01-01

A series of subscale cold flow tests was performed to quantify the gas flow characteristics at the aft end of the Space Shuttle Solid Rocket Motor. This information was used to support the analyses of the redesigned nozzle/case joint. A portion of the thermal loads at the joint are due to the circumferential velocities and pressure gradients caused primarily by the gimbaling of the submerged nose TVC nozzle. When the nozzle centerline is vectored with respect to the motor centerline, asymmetries are set up in the flow field under the submerged nozzle and immediately adjacent to the nozzle/case joint. Specific program objectives included: determination of the effects of nozzle gimbal angle and propellant geometry on the circumferential flow field; measurement of the static pressure and gas velocities in the vicinity of the nozzle/case joint; use of scaling laws to apply the subscale cold flow data to the full scale SRM; and generation of data for use in validation of 3-D computational fluid dynamic, CFD, models of the SRM flow field. These tests were conducted in the NASA Marshall Space Flight Center Airflow Facility with a 7.5 percent scale model of the aft segment of the SRM. Static and dynamic pressures were measured in the model to quantify the flow field. Oil flow data was also acquired to obtain qualitative visual descriptions of the flow field. Nozzle gimbal angles of 0, 3.5, and 7 deg were used with propellant grain configurations corresponding to motor burn times of 0, 9, 19, and 114 seconds. This experimental program was successful in generating velocity and pressure gradient data for the flow field around the submerged nose nozzle of the Space Shuttle SRM at various burn times and gimbal angles. The nature of the flow field adjacent to the nozzle/case joint was determined with oil droplet streaks, and the velocity and pressure gradients were quantified with pitot probes and wall static pressure measurements. The data was applied to the full scale SRM thru a scaling analysis and the results compared well with the 3-D computational fluid dynamics computer model.

Techniques d'inspection par ondes guidees ultrasonores d'assemblages brases dans des reacteurs aeronautiques =

NASA Astrophysics Data System (ADS)

Comot, Pierre

L'industrie aeronautique, cherche a etudier la possibilite d'utiliser de maniere structurelle des joints brases, dans une optique de reduction de poids et de cout. Le developpement d'une methode d'evaluation rapide, fiable et peu couteuse pour evaluer l'integrite structurelle des joints apparait donc indispensable. La resistance mecanique d'un joint brase dependant principalement de la quantite de phase fragile dans sa microstructure. Les ondes guidees ultrasonores permettent de detecter ce type de phase lorsqu'elles sont couplees a une mesure spatio-temporelle. De plus la nature de ce type d'ondes permet l'inspection de joints ayant des formes complexes. Ce memoire se concentre donc sur le developpement d'une technique basee sur l'utilisation d'ondes guidees ultrasonores pour l'inspection de joints brases a recouvrement d'Inconel 625 avec comme metal d'apport du BNi-2. Dans un premiers temps un modele elements finis du joint a ete utilise pour simuler la propagation des ultrasons et optimiser les parametres d'inspection, la simulation a permis egalement de demontrer la faisabilite de la technique pour la detection de la quantite de phase fragile dans ce type de joints. Les parametres optimises sont la forme de signal d'excitation, sa frequence centrale et la direction d'excitation. Les simulations ont montre que l'energie de l'onde ultrasonore transmise a travers le joint aussi bien que celle reflechie, toutes deux extraites des courbes de dispersion, etaient proportionnelles a la quantite de phase fragile presente dans le joint et donc cette methode permet d'identifier la presence ou non d'une phase fragile dans ce type de joint. Ensuite des experimentations ont ete menees sur trois echantillons typiques presentant differentes quantites de phase fragile dans le joint, pour obtenir ce type d'echantillons differents temps de brasage ont ete utilises (1, 60 et 180 min). Pour cela un banc d'essai automatise a ete developpe permettant d'effectuer une analyse similaire a celle utilisee en simulation. Les parametres experimentaux ayant ete choisis en accord avec l'optimisation effectuee lors des simulations et apres une premiere optimisation du procede experimental. Finalement les resultats experimentaux confirment les resultats obtenus en simulation, et demontrent le potentiel de la methode developpee.

Identifying seawater intrusion in coastal areas by means of 1D and quasi-2D joint inversion of TDEM and VES data

NASA Astrophysics Data System (ADS)

Martínez-Moreno, F. J.; Monteiro-Santos, F. A.; Bernardo, I.; Farzamian, M.; Nascimento, C.; Fernandes, J.; Casal, B.; Ribeiro, J. A.

2017-09-01

Seawater intrusion is an increasingly widespread problem in coastal aquifers caused by climate changes -sea-level rise, extreme phenomena like flooding and droughts- and groundwater depletion near to the coastline. To evaluate and mitigate the environmental risks of this phenomenon it is necessary to characterize the coastal aquifer and the salt intrusion. Geophysical methods are the most appropriate tool to address these researches. Among all geophysical techniques, electrical methods are able to detect seawater intrusions due to the high resistivity contrast between saltwater, freshwater and geological layers. The combination of two or more geophysical methods is recommended and they are more efficient when both data are inverted jointly because the final model encompasses the physical properties measured for each methods. In this investigation, joint inversion of vertical electric and time domain soundings has been performed to examine seawater intrusion in an area within the Ferragudo-Albufeira aquifer system (Algarve, South of Portugal). For this purpose two profiles combining electrical resistivity tomography (ERT) and time domain electromagnetic (TDEM) methods were measured and the results were compared with the information obtained from exploration drilling. Three different inversions have been carried out: single inversion of the ERT and TDEM data, 1D joint inversion and quasi-2D joint inversion. Single inversion results identify seawater intrusion, although the sedimentary layers detected in exploration drilling were not well differentiated. The models obtained with 1D joint inversion improve the previous inversion due to better detection of sedimentary layer and the seawater intrusion appear to be better defined. Finally, the quasi-2D joint inversion reveals a more realistic shape of the seawater intrusion and it is able to distinguish more sedimentary layers recognised in the exploration drilling. This study demonstrates that the quasi-2D joint inversion improves the previous inversions methods making it a powerful tool applicable to different research areas.

Active Vibration Control of a Large Flexible Manipulator by Inertial Force and Joint Torque. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lee, Soo Han

1988-01-01

The efficiency and positional accuracy of a lightweight flexible manipulator are limited by its flexural vibrations, which last after a gross motion is completed. The vibration delays subsequent operations. In the proposed work, the vibration is suppressed by inertial force of a small arm in addition to the joint actuators and passive damping treatment. The proposed approach is: (1) Dynamic modeling of a combined system, a large flexible manipulator and a small arm, (2) Determination of optimal sensor location and controller algorithm, and (3) Verification of the fitness of model and the performance of controller.

False ankylosis of the temporomandibular joint in a cat. Correction by partial zygomatic arch resection.

PubMed

Larguier, L; Jamet, N

2015-01-01

To describe the use of two-dimensional computer-assisted tomography (CT) with three-dimensional (3D) reconstruction in the diagnosis and planning of surgical treatment of a case of false ankylosis of the temporomandibular joint. A young European Shorthaired cat was presented with the complaint of inability to eat and open its jaws. A CT scan with 3D reconstruction allowed visualization of the lesion which was causing extra-articular ankylosis of the temporomandibular joint. Surgery was performed to resect an osseous lesion of the zygomatic arch, thus freeing the temporomandibular joint. Postoperative physical therapy was initiated immediately following surgery, and then carried out by the owner with a one year follow-up. Clinical examination of the cat was performed during regular office visits (at 1 month and 3 months following surgery), which allowed objective assessment of postoperative recuperation. At the end of a year, the owners reported that the cat had maintained sufficient jaw opening without any signs consistent with chronic pain. Computed tomography scan with 3D reconstruction allowed planning of the surgical correction of extra-articular ankylosis of the temporomandibular joint, and in this case condylectomy was avoided, since temporomandibular joint range-of-motion was maintained.

Computer tomography prototyping and virtual procedure simulation in difficult cases of hip replacement surgery.

PubMed

Parchi, Paolo Domenico; Ferrari, Vincenzo; Piolanti, Nicola; Andreani, Lorenzo; Condino, Sara; Evangelisti, Gisberto; Lisanti, Michele

2013-09-01

Each year approximately 1 million total hip replacements (THR) are performed worldwide. A percentage of failure due to surgical approach and imprecise implant placement still exists. These result in several serious complications. We propose an approach to plan, to simulate, and to assist prosthesis implantation for difficult cases of THR based on 3-D virtual models, generated by segmenting patients' CT images, 3-D solid models, obtained by rapid prototyping (RP), and virtual procedure simulation. We carried out 8 THR with the aid of 3-D reconstruction and RP. After each procedure a questionnaire was submitted to the surgeon to assess the perceived added value of the technology. In all cases, the surgeon evaluated the 3-D model as useful in order to perform the planning. The clinical results showed a mean increase in the Harris Hip Score of about 42.5 points. The mean time of prototyping was 7.3 hours, (min 3.5 hours, max 9.3 hours). The mean surgery time was 65 minutes (min 50 minutes, max 88 minutes). Our study suggests that meticulous preoperative planning is necessary in front of a great aberration of the joint and in absence of normal anatomical landmarks, CT scan is mandatory, and 3-D reconstruction with solid model is useful.

Non-driving intersegmental knee moments in cycling computed using a model that includes three-dimensional kinematics of the shank/foot and the effect of simplifying assumptions.

PubMed

Gregersen, Colin S; Hull, M L

2003-06-01

Assessing the importance of non-driving intersegmental knee moments (i.e. varus/valgus and internal/external axial moments) on over-use knee injuries in cycling requires the use of a three-dimensional (3-D) model to compute these loads. The objectives of this study were: (1) to develop a complete, 3-D model of the lower limb to calculate the 3-D knee loads during pedaling for a sample of the competitive cycling population, and (2) to examine the effects of simplifying assumptions on the calculations of the non-driving knee moments. The non-driving knee moments were computed using a complete 3-D model that allowed three rotational degrees of freedom at the knee joint, included the 3-D inertial loads of the shank/foot, and computed knee loads in a shank-fixed coordinate system. All input data, which included the 3-D segment kinematics and the six pedal load components, were collected from the right limb of 15 competitive cyclists while pedaling at 225 W and 90 rpm. On average, the peak varus and internal axial moments of 7.8 and 1.5 N m respectively occurred during the power stroke whereas the peak valgus and external axial moments of 8.1 and 2.5 N m respectively occurred during the recovery stroke. However, the non-driving knee moments were highly variable between subjects; the coefficients of variability in the peak values ranged from 38.7% to 72.6%. When it was assumed that the inertial loads of the shank/foot for motion out of the sagittal plane were zero, the root-mean-squared difference (RMSD) in the non-driving knee moments relative to those for the complete model was 12% of the peak varus/valgus moment and 25% of the peak axial moment. When it was also assumed that the knee joint was revolute with the flexion/extension axis perpendicular to the sagittal plane, the RMSD increased to 24% of the peak varus/valgus moment and 204% of the peak axial moment. Thus, the 3-D orientation of the shank segment has a major affect on the computation of the non-driving knee moments, while the inertial contributions to these loads for motions out of the sagittal plane are less important.

Prescribing joint co-ordinates during model preparation to improve inverse kinematic estimates of elbow joint angles.

PubMed

Wells, D J M; Alderson, J A; Dunne, J; Elliott, B C; Donnelly, C J

2017-01-25

To appropriately use inverse kinematic (IK) modelling for the assessment of human motion, a musculoskeletal model must be prepared 1) to match participant segment lengths (scaling) and 2) to align the model׳s virtual markers positions with known, experimentally derived kinematic marker positions (marker registration). The purpose of this study was to investigate whether prescribing joint co-ordinates during the marker registration process (within the modelling framework OpenSim) will improve IK derived elbow kinematics during an overhead sporting task. To test this, the upper limb kinematics of eight cricket bowlers were recorded during two testing sessions, with a different tester each session. The bowling trials were IK modelled twice: once with an upper limb musculoskeletal model prepared with prescribed participant specific co-ordinates during marker registration - MR PC - and once with the same model prepared without prescribed co-ordinates - MR; and by an established direct kinematic (DK) upper limb model. Whilst both skeletal model preparations had strong inter-tester repeatability (MR: Statistical Parametric Mapping (SPM1D)=0% different; MR PC : SPM1D=0% different), when compared with DK model elbow FE waveform estimates, IK estimates using the MR PC model (RMSD=5.2±2.0°, SPM1D=68% different) were in closer agreement than the estimates from the MR model (RMSD=44.5±18.5°, SPM1D=100% different). Results show that prescribing participant specific joint co-ordinates during the marker registration phase of model preparation increases the accuracy and repeatability of IK solutions when modelling overhead sporting tasks in OpenSim. Copyright © 2016 Elsevier Ltd. All rights reserved.

Progress and achievements of R&D activities for the ITER vacuum vessel

NASA Astrophysics Data System (ADS)

Nakahira, M.; Takahashi, H.; Koizumi, K.; Onozuka, M.; Ioki, K.

2001-04-01

The Full Scale Sector Model Project, which was initiated in 1995 as one of the Seven Large Projects for ITER R&D, has been continued with the joint effort of the ITER Joint Central Team and the Japanese, Russian Federation and United States Home Teams. The fabrication of a full scale 18° toroidal sector, which is composed of two 9° sectors spliced at the port centre, was successfully completed in September 1997 with a dimensional accuracy of +/-3 mm for the total height and total width. Both sectors were shipped to the test site at the Japan Atomic Energy Research Institute and the integration test of the sectors was begun in October 1997. The integration test involves the adjustment of field joints, automatic narrow gap tungsten inert gas welding of field joints with splice plates and inspection of the joints by ultrasonic testing, as required for the initial assembly of the ITER vacuum vessel. This first demonstration of field joint welding and the performance test of the mechanical characteristics were completed in May 1998, and all the results obtained have satisfied the ITER design. In addition to these tests, integration with the midplane port extension fabricated by the Russian Home Team by using a fully remotized welding and cutting system developed by the US Home Team was completed in March 2000. The article describes the progress, achievements and latest status of the R&D activities for the ITER vacuum vessel.

Computational analysis on plug-in hybrid electric motorcycle chassis

NASA Astrophysics Data System (ADS)

Teoh, S. J.; Bakar, R. A.; Gan, L. M.

2013-12-01

Plug-in hybrid electric motorcycle (PHEM) is an alternative to promote sustainability lower emissions. However, the PHEM overall system packaging is constrained by limited space in a motorcycle chassis. In this paper, a chassis applying the concept of a Chopper is analysed to apply in PHEM. The chassis 3dimensional (3D) modelling is built with CAD software. The PHEM power-train components and drive-train mechanisms are intergraded into the 3D modelling to ensure the chassis provides sufficient space. Besides that, a human dummy model is built into the 3D modelling to ensure the rider?s ergonomics and comfort. The chassis 3D model then undergoes stress-strain simulation. The simulation predicts the stress distribution, displacement and factor of safety (FOS). The data are used to identify the critical point, thus suggesting the chassis design is applicable or need to redesign/ modify to meet the require strength. Critical points mean highest stress which might cause the chassis to fail. This point occurs at the joints at triple tree and bracket rear absorber for a motorcycle chassis. As a conclusion, computational analysis predicts the stress distribution and guideline to develop a safe prototype chassis.

Modeling Computer Communication Networks in a Realistic 3D Environment

DTIC Science & Technology

2010-03-01

50 2. Comparison of visualization tools . . . . . . . . . . . . . . . . . 75 xi List of Abbreviations Abbreviation Page 2D two-dimensional...International Conference on, 77 –84, 2001. 20. National Defense and the Canadian Forces. “Joint Fires Support”. URL http: //www.cfd-cdf.forces.gc.ca/sites/ page ...UNLIMITED. Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour

Evaluation Transportability Testing of the Joint Modular Intermodal Platform (JMIP) Unit #4, TP-94-01, Transportability Testing Procedures

DTIC Science & Technology

2007-07-01

447 3893 VSN: NL1FR5 MFG Serial #: T-018447EFJM Weight: 19,340 lbs 3-1 5. Semitrailer, flatbed , breakbulk/container transporter, 22.5 ton Model...CHAFTING PIECE, 118" X 6" X 40" PLYWOOD, (I REaD). LAMINATE TO BEARING PIECE W16-6d NAILS EVENLY SPACED. SIDE STRAPPING BOARD ASSEMBLY (2 REOD) (I

3D Cosmic Ray Muon Tomography from an Underground Tunnel

DOE PAGES

Guardincerri, Elena; Rowe, Charlotte Anne; Schultz-Fellenz, Emily S.; ...

2017-03-31

Here, we present an underground cosmic ray muon tomographic experiment imaging 3D density of overburden, part of a joint study with differential gravity. Muon data were acquired at four locations within a tunnel beneath Los Alamos, New Mexico, and used in a 3D tomographic inversion to recover the spatial variation in the overlying rock–air interface, and compared with a priori knowledge of the topography. Densities obtained exhibit good agreement with preliminary results of the gravity modeling, which will be presented elsewhere, and are compatible with values reported in the literature. The modeled rock–air interface matches that obtained from LIDAR withinmore » 4 m, our resolution, over much of the model volume. This experiment demonstrates the power of cosmic ray muons to image shallow geological targets using underground detectors, whose development as borehole devices will be an important new direction of passive geophysical imaging.« less

3D Cosmic Ray Muon Tomography from an Underground Tunnel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guardincerri, Elena; Rowe, Charlotte Anne; Schultz-Fellenz, Emily S.

Here, we present an underground cosmic ray muon tomographic experiment imaging 3D density of overburden, part of a joint study with differential gravity. Muon data were acquired at four locations within a tunnel beneath Los Alamos, New Mexico, and used in a 3D tomographic inversion to recover the spatial variation in the overlying rock–air interface, and compared with a priori knowledge of the topography. Densities obtained exhibit good agreement with preliminary results of the gravity modeling, which will be presented elsewhere, and are compatible with values reported in the literature. The modeled rock–air interface matches that obtained from LIDAR withinmore » 4 m, our resolution, over much of the model volume. This experiment demonstrates the power of cosmic ray muons to image shallow geological targets using underground detectors, whose development as borehole devices will be an important new direction of passive geophysical imaging.« less

3D Cosmic Ray Muon Tomography from an Underground Tunnel

NASA Astrophysics Data System (ADS)

Guardincerri, Elena; Rowe, Charlotte; Schultz-Fellenz, Emily; Roy, Mousumi; George, Nicolas; Morris, Christopher; Bacon, Jeffrey; Durham, Matthew; Morley, Deborah; Plaud-Ramos, Kenie; Poulson, Daniel; Baker, Diane; Bonneville, Alain; Kouzes, Richard

2017-05-01

We present an underground cosmic ray muon tomographic experiment imaging 3D density of overburden, part of a joint study with differential gravity. Muon data were acquired at four locations within a tunnel beneath Los Alamos, New Mexico, and used in a 3D tomographic inversion to recover the spatial variation in the overlying rock-air interface, and compared with a priori knowledge of the topography. Densities obtained exhibit good agreement with preliminary results of the gravity modeling, which will be presented elsewhere, and are compatible with values reported in the literature. The modeled rock-air interface matches that obtained from LIDAR within 4 m, our resolution, over much of the model volume. This experiment demonstrates the power of cosmic ray muons to image shallow geological targets using underground detectors, whose development as borehole devices will be an important new direction of passive geophysical imaging.

Diagnostic index of three-dimensional osteoarthritic changes in temporomandibular joint condylar morphology

PubMed Central

Gomes, Liliane R.; Gomes, Marcelo; Jung, Bryan; Paniagua, Beatriz; Ruellas, Antonio C.; Gonçalves, João Roberto; Styner, Martin A.; Wolford, Larry; Cevidanes, Lucia

2015-01-01

Abstract. This study aimed to investigate imaging statistical approaches for classifying three-dimensional (3-D) osteoarthritic morphological variations among 169 temporomandibular joint (TMJ) condyles. Cone-beam computed tomography scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA), 15 subjects at initial diagnosis of OA, and 7 healthy controls. Three-dimensional surface models of the condyles were constructed and SPHARM-PDM established correspondent points on each model. Multivariate analysis of covariance and direction-projection-permutation (DiProPerm) were used for testing statistical significance of the differences between the groups determined by clinical and radiographic diagnoses. Unsupervised classification using hierarchical agglomerative clustering was then conducted. Compared with healthy controls, OA average condyle was significantly smaller in all dimensions except its anterior surface. Significant flattening of the lateral pole was noticed at initial diagnosis. We observed areas of 3.88-mm bone resorption at the superior surface and 3.10-mm bone apposition at the anterior aspect of the long-term OA average model. DiProPerm supported a significant difference between the healthy control and OA group (p-value=0.001). Clinically meaningful unsupervised classification of TMJ condylar morphology determined a preliminary diagnostic index of 3-D osteoarthritic changes, which may be the first step towards a more targeted diagnosis of this condition. PMID:26158119

High resolution three-dimensional photoacoustic imaging of human finger joints in vivo

NASA Astrophysics Data System (ADS)

Xi, Lei; Jiang, Huabei

2015-08-01

We present a method for noninvasively imaging the hand joints using a three-dimensional (3D) photoacoustic imaging (PAI) system. This 3D PAI system utilizes cylindrical scanning in data collection and virtual-detector concept in image reconstruction. The maximum lateral and axial resolutions of the PAI system are 70 μm and 240 μm. The cross-sectional photoacoustic images of a healthy joint clearly exhibited major internal structures including phalanx and tendons, which are not available from the current photoacoustic imaging methods. The in vivo PAI results obtained are comparable with the corresponding 3.0 T MRI images of the finger joint. This study suggests that the proposed method has the potential to be used in early detection of joint diseases such as osteoarthritis.

A 3D Joint Simulation Platform for Multiband_A Case Study in the Huailai Soybean and Maize Field

NASA Astrophysics Data System (ADS)

Zhang, Y.; Qinhuo, L.; Du, Y.; Huang, H.

2016-12-01

Canopy radiation and scattering signal contains abundant vegetation information. One can quantitatively retrieve the biophysical parameters by building canopy radiation and scattering models and inverting them. Joint simulation of the 3D models for different spectral (frequency) domains may produce complementary advantages and improves the precision. However, most of the currently models were based on one or two spectral bands (e.g. visible and thermal inferred bands, or visible and microwave bands). This manuscript established a 3D radiation and scattering simulation system which can simulate the BRDF, DBT, and backscattering coefficient based on the same structural description. The system coupled radiosity graphic model, Thermal RGM model and coherent microwave model by Yang Du for VIS/NIR, TIR, and MW, respectively. The models simulating the leaf spectral characteristics, component temperatures and dielectric properties were also coupled into the joint simulation system to convert the various parameters into fewer but more unified parameters. As a demonstration of our system, we applied the established system to simulate a mixed field with soybeans and maize based on the Huailai experiment data in August, 2014. With the help of Xfrog software, we remodeled soybean and maize in ".obj" and ".mtl" format. We extracted the structure information of the soybean and maize by statistics of the ".obj" files. We did simulations on red, NIR, TIR, C and L band. The simulation results were validated by the multi-angular observation data of Huailai experiment. Also, the spacial distribution (horizontal and vertical), leaf area index (LAI), leaf angle distribution (LAD), vegetation water content (VWC) and the incident observation geometry were analyzed in details. Validated by the experiment data, we indicate that the simulations of multiband were quite well. Because the crops were planted in regular rows and the maize and soybeans were with different height, different LAI, different LAD and different VWC, we did the sensitive analysis by changing on one of them and fixed the other parameters. The analysis showed that the parameters influenced the radiation and scattering signal of different spectral (frequency) with varying degrees.

Constraints on active region coronal heating properties from observations and modeling of chromospheric, transition region, and coronal emission

NASA Astrophysics Data System (ADS)

Testa, P.; Polito, V.; De Pontieu, B.; Carlsson, M.; Reale, F.; Allred, J. C.; Hansteen, V. H.

2017-12-01

We investigate coronal heating properties in active region cores in non-flaring conditions, using high spatial, spectral, and temporal resolution chromospheric/transition region/coronal observations coupled with detailed modeling. We will focus, in particular, on observations with the Interface Region Imaging Spectrograph (IRIS), joint with observations with Hinode (XRT and EIS) and SDO/AIA. We will discuss how these observations and models (1D HD and 3D MHD, with the RADYN and Bifrost codes) provide useful diagnostics of the coronal heating processes and mechanisms of energy transport.

A three-dimensional finite element model for biomechanical analysis of the hip.

PubMed

Chen, Guang-Xing; Yang, Liu; Li, Kai; He, Rui; Yang, Bin; Zhan, Yan; Wang, Zhi-Jun; Yu, Bing-Nin; Jian, Zhe

2013-11-01

The objective of this study was to construct a three-dimensional (3D) finite element model of the hip. The images of the hip were obtained from Chinese visible human dataset. The hip model includes acetabular bone, cartilage, labrum, and bone. The cartilage of femoral head was constructed using the AutoCAD and Solidworks software. The hip model was imported into ABAQUS analysis system. The contact surface of the hip joint was meshed. To verify the model, the single leg peak force was loaded, and contact area of the cartilage and labrum of the hip and pressure distribution in these structures were observed. The constructed 3D hip model reflected the real hip anatomy. Further, this model reflected biomechanical behavior similar to previous studies. In conclusion, this 3D finite element hip model avoids the disadvantages of other construction methods, such as imprecision of cartilage construction and the absence of labrum. Further, it provides basic data critical for accurately modeling normal and abnormal loads, and the effects of abnormal loads on the hip.

Development of a sensor coordinated kinematic model for neural network controller training

NASA Technical Reports Server (NTRS)

Jorgensen, Charles C.

1990-01-01

A robotic benchmark problem useful for evaluating alternative neural network controllers is presented. Specifically, it derives two camera models and the kinematic equations of a multiple degree of freedom manipulator whose end effector is under observation. The mapping developed include forward and inverse translations from binocular images to 3-D target position and the inverse kinematics of mapping point positions into manipulator commands in joint space. Implementation is detailed for a three degree of freedom manipulator with one revolute joint at the base and two prismatic joints on the arms. The example is restricted to operate within a unit cube with arm links of 0.6 and 0.4 units respectively. The development is presented in the context of more complex simulations and a logical path for extension of the benchmark to higher degree of freedom manipulators is presented.

Development of a hip joint model for finite volume simulations.

PubMed

Cardiff, P; Karač, A; FitzPatrick, D; Ivanković, A

2014-01-01

This paper establishes a procedure for numerical analysis of a hip joint using the finite volume method. Patient-specific hip joint geometry is segmented directly from computed tomography and magnetic resonance imaging datasets and the resulting bone surfaces are processed into a form suitable for volume meshing. A high resolution continuum tetrahedral mesh has been generated, where a sandwich model approach is adopted; the bones are represented as a stiffer cortical shells surrounding more flexible cancellous cores. Cartilage is included as a uniform thickness extruded layer and the effect of layer thickness is investigated. To realistically position the bones, gait analysis has been performed giving the 3D positions of the bones for the full gait cycle. Three phases of the gait cycle are examined using a finite volume based custom structural contact solver implemented in open-source software OpenFOAM.

Customized Knee Prosthesis in Treatment of Giant Cell Tumors of the Proximal Tibia: Application of 3-Dimensional Printing Technology in Surgical Design.

PubMed

Luo, Wenbin; Huang, Lanfeng; Liu, He; Qu, Wenrui; Zhao, Xin; Wang, Chenyu; Li, Chen; Yu, Tao; Han, Qing; Wang, Jincheng; Qin, Yanguo

2017-04-07

BACKGROUND We explored the application of 3-dimensional (3D) printing technology in treating giant cell tumors (GCT) of the proximal tibia. A tibia block was designed and produced through 3D printing technology. We expected that this 3D-printed block would fill the bone defect after en-bloc resection. Importantly, the block, combined with a standard knee joint prosthesis, provided attachments for collateral ligaments of the knee, which can maintain knee stability. MATERIAL AND METHODS A computed tomography (CT) scan was taken of both knee joints in 4 patients with GCT of the proximal tibia. We developed a novel technique - the real-size 3D-printed proximal tibia model - to design preoperative treatment plans. Hence, with the application of 3D printing technology, a customized proximal tibia block could be designed for each patient individually, which fixed the bone defect, combined with standard knee prosthesis. RESULTS In all 4 cases, the 3D-printed block fitted the bone defect precisely. The motion range of the affected knee was 90 degrees on average, and the soft tissue balance and stability of the knee were good. After an average 7-month follow-up, the MSTS score was 19 on average. No sign of prosthesis fracture, loosening, or other relevant complications were detected. CONCLUSIONS This technique can be used to treat GCT of the proximal tibia when it is hard to achieve soft tissue balance after tumor resection. 3D printing technology simplified the design and manufacturing progress of custom-made orthopedic medical instruments. This new surgical technique could be much more widely applied because of 3D printing technology.

The application of 3-dimensional printing for preoperative planning in oral and maxillofacial surgery in dogs and cats.

PubMed

Winer, Jenna N; Verstraete, Frank J M; Cissell, Derek D; Lucero, Steven; Athanasiou, Kyriacos A; Arzi, Boaz

2017-10-01

To describe the application of 3-dimensional (3D) printing in advanced oral and maxillofacial surgery (OMFS) and to discuss the benefits of this modality in surgical planning, student and resident training, and client education. Retrospective case series. Client-owned dogs (n = 28) and cats (n = 4) with 3D printing models of the skulls. The medical records of 32 cases with 3D printing prior to major OMFS were reviewed. Indications for 3D printing included preoperative planning for mandibular reconstruction after mandibulectomy (n = 12 dogs) or defect nonunion fracture (n = 6 dogs, 2 cats), mapping of ostectomy location for temporomandibular joint ankylosis or pseudoankylosis (n = 4 dogs), assessment of palatal defects (n = 2 dogs, 1 cat), improved understanding of complex anatomy in cases of neoplasia located in challenging locations (n = 2 dogs, 1 cat), and in cases of altered anatomy secondary to trauma (n = 2 dogs). In the authors' experience, 3D printed models serve as excellent tools for OMFS planning and resident training. Furthermore, 3D printed models are a valuable resource to improve clients' understanding of the pet's disorder and the recommended treatment. Three-dimensional printed models should be considered viable tools for surgical planning, resident training, and client education in candidates for complex OMFS. © 2017 The American College of Veterinary Surgeons.

Finite element thermal analysis for PMMA/st.st.304 laser direct joining

NASA Astrophysics Data System (ADS)

Hussein, Furat I.; Salloomi, Kareem N.; Akman, E.; Hajim, K. I.; Demir, A.

2017-01-01

This work is concerned with building a three-dimensional (3D) ab-initio models that is capable of predicting the thermal distribution of laser direct joining processes between Polymethylmethacrylate (PMMA) and stainless steel 304(st.st.304). ANSYS® simulation based on finite element analysis (FEA) was implemented for materials joining in two modes; laser transmission joining (LTJ) and conduction joining (CJ). ANSYS® simulator was used to explore the thermal environment of the joints during joining (heating time) and after joining (cooling time). For both modes, the investigation is carried out when the laser spot is at the middle of the joint width, at 15 mm from the commencement point (joint edge) at traveling time of 3.75 s. Process parameters involving peak power (Pp=3 kW), pulse duration (τ=5 ms), pulse repetition rate (PRR=20 Hz) and scanning speed (v=4 mm/s) are applied for both modes.

Intra-articular injection of collagenase induced experimental osteoarthritis of the lumbar facet joint in rats

PubMed Central

Yeh, Tsu-Te; Wen, Zhi-Hong; Lee, Herng-Sheng; Lee, Chian-Her; Yang, Zhi; Jean, Yen-Hsuan; Nimni, Marcel E.; Han, Bo

2008-01-01

We aimed to establish an animal model to investigate primary osteoarthritis of the lumbar facet joints after collagenase injection in rats and its effects on chondrocyte apoptosis. We hypothesized that osteoarthritic-like changes would be induced by collagenase injection and that apoptosis of chondrocytes would increase. Collagenase (1, 10, or 50 U) or saline (control) was injected into the lumbar facet joints. The histology and histochemistry of cartilage, synovium, and subchondral bone were examined at 1, 3, and 6 weeks after surgery. Apoptotic cells induced by 1 U of collagenase were quantified using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Degeneration of the cartilage and changes to the synovium and subchondral bone were dependent on both the doses of collagenase and the time after surgery. There were significantly more apoptotic chondrocytes in collagenase-treated joints than in control (P < 0.001 at 1 and 3 weeks and P < 0.05 at 6 weeks). Thus, lumbar facet joints subjected to collagenase developed osteoarthritic-like changes that could be quantified and compared. This model provides a useful tool for further study on the effects of compounds that have the potential to inhibit enzyme-associated damage to cartilage. PMID:18224353

Quantitative three-dimensional photoacoustic tomography of the finger joints: an in vivo study

NASA Astrophysics Data System (ADS)

Sun, Yao; Sobel, Eric; Jiang, Huabei

2009-11-01

We present for the first time in vivo full three-dimensional (3-D) photoacoustic tomography (PAT) of the distal interphalangeal joint in a human subject. Both absorbed energy density and absorption coefficient images of the joint are quantitatively obtained using our finite-element-based photoacoustic image reconstruction algorithm coupled with the photon diffusion equation. The results show that major anatomical features in the joint along with the side arteries can be imaged with a 1-MHz transducer in a spherical scanning geometry. In addition, the cartilages associated with the joint can be quantitatively differentiated from the phalanx. This in vivo study suggests that the 3-D PAT method described has the potential to be used for early diagnosis of joint diseases such as osteoarthritis and rheumatoid arthritis.

Mechanical characterization and validation of poly (methyl methacrylate)/multi walled carbon nanotube composite for the polycentric knee joint.

PubMed

Arun, S; Kanagaraj, S

2015-10-01

Trans femoral amputation is one of the most uncomfortable surgeries in patient׳s life, where the prosthesis consisting of a socket, knee joint, pylon and foot is used to do the walking activities. The artificial prosthetic knee joint imitates the functions of human knee to achieve the flexion-extension for the above knee amputee. The objective of present work is to develop a light weight composite material for the knee joint to reduce the metabolic cost of an amputee. Hence, an attempt was made to study the mechanical properties of multi walled carbon nanotubes (MWCNT) reinforced Poly (methyl methacrylate) (PMMA) prepared through melt mixing technique and optimize the concentration of reinforcement. The PMMA nanocomposites were prepared by reinforcing 0, 0.1, 0.2, 0.25, 0.3 and 0.4 wt% of MWCNT using injection moulding machine via twin screw extruder. It is observed that the tensile and flexural strength of PMMA, which were studied as per ASTM D638 and D790, respectively, were increased by 32.9% and 26.3% till 0.25 wt% reinforcement of MWCNT. The experimental results of strength and modulus were compared with theoretical prediction, where a good correlation was noted. It is concluded that the mechanical properties of PMMA were found to be increased to maximum at 0.25 wt% reinforcement of MWCNT, where the Pukanszky model and modified Halpin-Tsai model are suggested to predict the strength and modulus, respectively, of the PMMA/MWCNT composite, which can be opted as a suitable materiel for the development of polycentric knee joint. Copyright © 2015 Elsevier Ltd. All rights reserved.

Validation and Comparison of 2D and 3D Codes for Nearshore Motion of Long Waves Using Benchmark Problems

NASA Astrophysics Data System (ADS)

Velioǧlu, Deniz; Cevdet Yalçıner, Ahmet; Zaytsev, Andrey

2016-04-01

Tsunamis are huge waves with long wave periods and wave lengths that can cause great devastation and loss of life when they strike a coast. The interest in experimental and numerical modeling of tsunami propagation and inundation increased considerably after the 2011 Great East Japan earthquake. In this study, two numerical codes, FLOW 3D and NAMI DANCE, that analyze tsunami propagation and inundation patterns are considered. Flow 3D simulates linear and nonlinear propagating surface waves as well as long waves by solving three-dimensional Navier-Stokes (3D-NS) equations. NAMI DANCE uses finite difference computational method to solve 2D depth-averaged linear and nonlinear forms of shallow water equations (NSWE) in long wave problems, specifically tsunamis. In order to validate these two codes and analyze the differences between 3D-NS and 2D depth-averaged NSWE equations, two benchmark problems are applied. One benchmark problem investigates the runup of long waves over a complex 3D beach. The experimental setup is a 1:400 scale model of Monai Valley located on the west coast of Okushiri Island, Japan. Other benchmark problem is discussed in 2015 National Tsunami Hazard Mitigation Program (NTHMP) Annual meeting in Portland, USA. It is a field dataset, recording the Japan 2011 tsunami in Hilo Harbor, Hawaii. The computed water surface elevation and velocity data are compared with the measured data. The comparisons showed that both codes are in fairly good agreement with each other and benchmark data. The differences between 3D-NS and 2D depth-averaged NSWE equations are highlighted. All results are presented with discussions and comparisons. Acknowledgements: Partial support by Japan-Turkey Joint Research Project by JICA on earthquakes and tsunamis in Marmara Region (JICA SATREPS - MarDiM Project), 603839 ASTARTE Project of EU, UDAP-C-12-14 project of AFAD Turkey, 108Y227, 113M556 and 213M534 projects of TUBITAK Turkey, RAPSODI (CONCERT_Dis-021) of CONCERT-Japan Joint Call and Istanbul Metropolitan Municipality are all acknowledged.

Quantitative in vivo HR-pQCT imaging of 3D wrist and metacarpophalangeal joint space width in rheumatoid arthritis.

PubMed

Burghardt, Andrew J; Lee, Chan Hee; Kuo, Daniel; Majumdar, Sharmila; Imboden, John B; Link, Thomas M; Li, Xiaojuan

2013-12-01

In this technique development study, high-resolution peripheral quantitative computed tomography (HR-pQCT) was applied to non-invasively image and quantify 3D joint space morphology of the wrist and metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA). HR-pQCT imaging (82 μm voxel-size) of the dominant hand was performed in patients with diagnosed rheumatoid arthritis (RA, N = 16, age: 52.6 ± 12.8) and healthy controls (CTRL, N = 7, age: 50.1 ± 15.0). An automated computer algorithm was developed to segment wrist and MCP joint spaces. The 3D distance transformation method was applied to spatially map joint space width, and summarized by the mean joint space width (JSW), minimal and maximal JSW (JSW.MIN, JSW.MAX), asymmetry (JSW.AS), and distribution (JSW.SD)-a measure of joint space heterogeneity. In vivo precision was determined for each measure by calculating the smallest detectable difference (SDD) and root mean square coefficient of variation (RMSCV%) of repeat scans. Qualitatively, HR-pQCT images and pseudo-color JSW maps showed global joint space narrowing, as well as regional and focal abnormalities in RA patients. In patients with radiographic JSN at an MCP, JSW.SD was two-fold greater vs. CTRL (p < 0.01), and JSW.MIN was more than two-fold lower (p < 0.001). Similarly, JSW.SD was significantly greater in the wrist of RA patients vs. CTRL (p < 0.05). In vivo precision was highest for JSW (SDD: 100 μm, RMSCV: 2.1%) while the SDD for JSW.MIN and JSW.SD were 370 and 110 μm, respectively. This study suggests that in vivo quantification of 3D joint space morphology from HR-pQCT, could improve early detection of joint damage in rheumatological diseases.

Quantitative In Vivo HR-pQCT Imaging of 3D Wrist and Metacarpophalangeal Joint Space Width In Rheumatoid Arthritis

PubMed Central

Burghardt, Andrew J.; Lee, Chan Hee; Kuo, Daniel; Majumdar, Sharmila; Imboden, John B.; Link, Thomas M.; Li, Xiaojuan

2013-01-01

In this technique development study, high-resolution peripheral quantitative computed tomography (HR-pQCT) was applied to non-invasively image and quantify 3D joint space morphology of the wrist and metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA). HR-pQCT imaging (82μm voxel-size) of the dominant hand was performed in patients with diagnosed rheumatoid arthritis (RA, N=16, age:52.6±12.8) and healthy controls (CTRL, N=7, age:50.1±15.0). An automated computer algorithm was developed to segment wrist and MCP joint spaces. The 3D distance transformation method was applied to spatially map joint space width, and summarized by the mean joint space width (JSW), minimal and maximal JSW (JSW.MIN, JSW.MAX), asymmetry (JSW.AS), and distribution (JSW.SD) – a measure of joint space heterogeneity. In vivo precision was determined for each measure by calculating the smallest detectable difference (SDD) and root mean square coefficient of variation (RMSCV%) of repeat scans. Qualitatively, HR-pQCT images and pseudo-color JSW maps showed global joint space narrowing, as well as regional and focal abnormalities in RA patients. In patients with radiographic JSN at an MCP, JSW.SD was two-fold greater versus CTRL (p<0.01), and JSW.MIN was more than two-fold lower (p<0.001). Similarly, JSW.SD was significantly greater in the wrist of RA patients versus CTRL (p<0.05). In vivo precision was highest for JSW (SDD: 100μm, RMSCV: 2.1%) while the SDD for JSW.MIN and JSW.SD were 370 and 110μm, respectively. This study suggests that in vivo quantification of 3D joint space morphology from HR-pQCT, could improve early detection of joint damage in rheumatological diseases. PMID:23887879

One- and multi-segment foot models lead to opposite results on ankle joint kinematics during gait: Implications for clinical assessment.

PubMed

Pothrat, Claude; Authier, Guillaume; Viehweger, Elke; Berton, Eric; Rao, Guillaume

2015-06-01

Biomechanical models representing the foot as a single rigid segment are commonly used in clinical or sport evaluations. However, neglecting internal foot movements could lead to significant inaccuracies on ankle joint kinematics. The present study proposed an assessment of 3D ankle kinematic outputs using two distinct biomechanical models and their application in the clinical flat foot case. Results of the Plug in Gait (one segment foot model) and the Oxford Foot Model (multisegment foot model) were compared for normal children (9 participants) and flat feet children (9 participants). Repeated measures of Analysis of Variance have been performed to assess the Foot model and Group effects on ankle joint kinematics. Significant differences were observed between the two models for each group all along the gait cycle. In particular for the flat feet group, opposite results between the Oxford Foot Model and the Plug in Gait were revealed at heelstrike, with the Plug in Gait showing a 4.7° ankle dorsal flexion and 2.7° varus where the Oxford Foot Model showed a 4.8° ankle plantar flexion and 1.6° valgus. Ankle joint kinematics of the flat feet group was more affected by foot modeling than normal group. Foot modeling appeared to have a strong influence on resulting ankle kinematics. Moreover, our findings showed that this influence could vary depending on the population. Studies involving ankle joint kinematic assessment should take foot modeling with caution. Copyright © 2015 Elsevier Ltd. All rights reserved.

3-D sonography for diagnosis of disk dislocation of the temporomandibular joint compared with MRI.

PubMed

Landes, Constantin A; Goral, Wojciech A; Sader, Robert; Mack, Martin G

2006-05-01

This study determines the value of three-dimensional (3-D) sonography for the assessment of disk dislocation of the temporomandibular joint (TMJ). Sixty-eight patients (i.e.,136 TMJ) with clinical dysfunction were examined by 272 sonographic 3-D scans. An 8- to 12.5-MHz transducer, angulated by step-motor, was used after picking a volume box on 2-D scan; magnetic resonance imaging followed immediately. Every TMJ was scrutinized in closed- and open-mouth position for normal or dislocated disk position. Fifty-three patients had complete data sets, i.e., 106 TMJ, 212 examinations. Sonographic examination took 5 min, with 74% specificity (62% closed-mouth; 85% open-mouth); sensitivity 53% (62/43%); accuracy 70% (62/77%); positive predictive value 49% (57/41%); and negative predictive value 77% (67/86%). This study encourages more research on the diagnostic capacity of 3-D TMJ sonography, with the advantage of multidimensional joint visualization. Although fair in specificity and negative predictive value, sensitivity and accuracy may ameliorate with future higher-sound frequency, real-time 3-D viewing and automated image analysis.

The numerical high cycle fatigue damage model of fillet weld joint under weld-induced residual stresses

NASA Astrophysics Data System (ADS)

Nguyen Van Do, Vuong

2018-04-01

In this study, a development of nonlinear continuum damage mechanics (CDM) model for multiaxial high cycle fatigue is proposed in which the cyclic plasticity constitutive model has been incorporated in the finite element (FE) framework. T-joint FE simulation of fillet welding is implemented to characterize sequentially coupled three-dimensional (3-D) of thermo-mechanical FE formulation and simulate the welding residual stresses. The high cycle fatigue damage model is then taken account into the fillet weld joints under the various cyclic fatigue load types to calculate the fatigue life considering the residual stresses. The fatigue crack initiation and the propagation in the present model estimated for the total fatigue is compared with the experimental results. The FE results illustrated that the proposed high cycle fatigue damage model in this study could become a powerful tool to effectively predict the fatigue life of the welds. Parametric studies in this work are also demonstrated that the welding residual stresses cannot be ignored in the computation of the fatigue life of welded structures.

Overview of Doing Business with SPAWAR Systems Command (SPAWAR)

DTIC Science & Technology

2011-08-22

School Girls Day Out FY07 – 1 school FY08 – 34 schools FY09 – 35 schools FY10 – 47 schools Material World Modules International Autonomous Underwater...s it e , a n d a ls o f rom t h e foll o vn n g link: e-CC Self -Service News The 23rd P.nnual Na v y Gold Coast Small Business O pportunity Conf...Opportunities 1. Requirements Office: Joint Program Manager - Information Systems (JPMIS) 2. Joint Effects Model (JEM) Increment 1 Sustainment 3

Automated muscle wrapping using finite element contact detection.

PubMed

Favre, Philippe; Gerber, Christian; Snedeker, Jess G

2010-07-20

Realistic muscle path representation is essential to musculoskeletal modeling of joint function. Algorithms predicting these muscle paths typically rely on a labor intensive predefinition of via points or underlying geometries to guide wrapping for given joint positions. While muscle wrapping using anatomically precise three-dimensional (3D) finite element (FE) models of bone and muscle has been achieved, computational expense and pre-processing associated with this approach exclude its use in applications such as subject-specific modeling. With the intention of combining advantageous features of both approaches, an intermediate technique relying on contact detection capabilities of commercial FE packages is presented. We applied the approach to the glenohumeral joint, and validated the method by comparison against existing experimental data. Individual muscles were modeled as a straight series of deformable beam elements and bones as anatomically precise 3D rigid bodies. Only the attachment locations and a default orientation of the undeformed muscle segment were pre-defined. The joint was then oriented in a static position of interest. The muscle segment free end was then moved along the shortest Euclidean path to its origin on the scapula, wrapping the muscle along bone surfaces by relying on software contact detection. After wrapping for a given position, the resulting moment arm was computed as the perpendicular distance from the line of action vector to the humeral head center of rotation. This approach reasonably predicted muscle length and moment arm for 27 muscle segments when compared to experimental measurements over a wide range of shoulder motion. Artificial via points or underlying contact geometries were avoided, contact detection and multiobject wrapping on the bone surfaces were automatic, and low computational cost permitted wrapping of individual muscles within seconds on a standard desktop PC. These advantages may be valuable for both general and subject-specific musculoskeletal modeling. 2010 Elsevier Ltd. All rights reserved.

Joint refraction and reflection travel-time tomography of multichannel and wide-angle seismic data

NASA Astrophysics Data System (ADS)

Begovic, Slaven; Meléndez, Adrià; Ranero, César; Sallarès, Valentí

2017-04-01

Both near-vertical multichannel (MCS) and wide-angle (WAS) seismic data are sensitive to same properties of sampled model, but commonly they are interpreted and modeled using different approaches. Traditional MCS images provide good information on position and geometry of reflectors especially in shallow, commonly sedimentary layers, but have limited or no refracted waves, which severely hampers the retrieval of velocity information. Compared to MCS data, conventional wide-angle seismic (WAS) travel-time tomography uses sparse data (generally stations are spaced by several kilometers). While it has refractions that allow retrieving velocity information, the data sparsity makes it difficult to define velocity and the geometry of geologic boundaries (reflectors) with the appropriate resolution, especially at the shallowest crustal levels. A well-known strategy to overcome these limitations is to combine MCS and WAS data into a common inversion strategy. However, the number of available codes that can jointly invert for both types of data is limited. We have adapted the well-known and widely-used joint refraction and reflection travel-time tomography code tomo2d (Korenaga et al, 2000), and its 3D version tomo3d (Meléndez et al, 2015), to implement streamer data and multichannel acquisition geometries. This allows performing joint travel-time tomographic inversion based on refracted and reflected phases from both WAS and MCS data sets. We show with a series of synthetic tests following a layer-stripping strategy that combining these two data sets into joint travel-time tomographic method the drawbacks of each data set are notably reduced. First, we have tested traditional travel-time inversion scheme using only WAS data (refracted and reflected phases) with typical acquisition geometry with one ocean bottom seismometer (OBS) each 10 km. Second, we have jointly inverted WAS refracted and reflected phases with only streamer (MCS) reflection travel-times. And at the end we have performed joint inversion of combined refracted and reflected phases from both data sets. MCS data set (synthetic) has been produced for a 8 km-long streamer and refracted phases used for the streamer have been downward continued (projected on the seafloor). Taking advantage of high redundancy of MCS data, the definition of geometry of reflectors and velocity of uppermost layers are much improved. Additionally, long- offset wide-angle refracted phases minimize velocity-depth trade-off of reflection travel-time inversion. As a result, the obtained models have increased accuracy in both velocity and reflector's geometry as compared to the independent inversion of each data set. This is further corroborated by performing a statistical parameter uncertainty analysis to explore the effects of unknown initial model and data noise in the linearized inversion scheme.

AxiSEM3D: a new fast method for global wave propagation in 3-D Earth models with undulating discontinuities

NASA Astrophysics Data System (ADS)

Leng, K.; Nissen-Meyer, T.; van Driel, M.; Al-Attar, D.

2016-12-01

We present a new, computationally efficient numerical method to simulate global seismic wave propagation in realistic 3-D Earth models with laterally heterogeneous media and finite boundary perturbations. Our method is a hybrid of pseudo-spectral and spectral element methods (SEM). We characterize the azimuthal dependence of 3-D wavefields in terms of Fourier series, such that the 3-D equations of motion reduce to an algebraic system of coupled 2-D meridional equations, which can be solved by a 2-D spectral element method (based on www.axisem.info). Computational efficiency of our method stems from lateral smoothness of global Earth models (with respect to wavelength) as well as axial singularity of seismic point sources, which jointly confine the Fourier modes of wavefields to a few lower orders. All boundary perturbations that violate geometric spherical symmetry, including Earth's ellipticity, topography and bathymetry, undulations of internal discontinuities such as Moho and CMB, are uniformly considered by means of a Particle Relabeling Transformation.The MPI-based high performance C++ code AxiSEM3D, is now available for forward simulations upon 3-D Earth models with fluid outer core, ellipticity, and both mantle and crustal structures. We show novel benchmarks for global wave solutions in 3-D mantle structures between our method and an independent, fully discretized 3-D SEM with remarkable agreement. Performance comparisons are carried out on three state-of-the-art tomography models, with seismic period going down to 5s. It is shown that our method runs up to two orders of magnitude faster than the 3-D SEM for such settings, and such computational advantage scales favourably with seismic frequency. By examining wavefields passing through hypothetical Gaussian plumes of varying sharpness, we identify in model-wavelength space the limits where our method may lose its advantage.

Advanced computational tools for 3-D seismic analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barhen, J.; Glover, C.W.; Protopopescu, V.A.

1996-06-01

The global objective of this effort is to develop advanced computational tools for 3-D seismic analysis, and test the products using a model dataset developed under the joint aegis of the United States` Society of Exploration Geophysicists (SEG) and the European Association of Exploration Geophysicists (EAEG). The goal is to enhance the value to the oil industry of the SEG/EAEG modeling project, carried out with US Department of Energy (DOE) funding in FY` 93-95. The primary objective of the ORNL Center for Engineering Systems Advanced Research (CESAR) is to spearhead the computational innovations techniques that would enable a revolutionary advancemore » in 3-D seismic analysis. The CESAR effort is carried out in collaboration with world-class domain experts from leading universities, and in close coordination with other national laboratories and oil industry partners.« less

Geoelectric Characterization of Thermal Water Aquifers Using 2.5D Inversion of VES Measurements

NASA Astrophysics Data System (ADS)

Gyulai, Á.; Szűcs, P.; Turai, E.; Baracza, M. K.; Fejes, Z.

2017-03-01

This paper presents a short theoretical summary of the series expansion-based 2.5D combined geoelectric weighted inversion (CGWI) method and highlights the advantageous way with which the number of unknowns can be decreased due to the simultaneous characteristic of this inversion. 2.5D CGWI is an approximate inversion method for the determination of 3D structures, which uses the joint 2D forward modeling of dip and strike direction data. In the inversion procedure, the Steiner's most frequent value method is applied to the automatic separation of dip and strike direction data and outliers. The workflow of inversion and its practical application are presented in the study. For conventional vertical electrical sounding (VES) measurements, this method can determine the parameters of complex structures more accurately than the single inversion method. Field data show that the 2.5D CGWI which was developed can determine the optimal location for drilling an exploratory thermal water prospecting well. The novelty of this research is that the measured VES data in dip and strike direction are jointly inverted by the 2.5D CGWI method.

Stress distribution in the temporo-mandibular joint discs during jaw closing: a high-resolution three-dimensional finite-element model analysis.

PubMed

Savoldelli, Charles; Bouchard, Pierre-Olivier; Loudad, Raounak; Baque, Patrick; Tillier, Yannick

2012-07-01

This study aims at analysing the stresses distribution in the temporomandibular joint (TMJ) using a complete high-resolution finite element model (FE Model). This model is used here to analyse the stresses distribution in the discs during a closing jaw cycle. In the end, this model enables the prediction of the stress evolution in the TMJ disc submitted to various loadings induced by mandibular trauma, surgery or parafunction. The geometric data for the model were obtained from MRI and CT scans images of a healthy male patient. Surface and volume meshes were successively obtained using a 3D image segmentation software (AMIRA(®)). Bone components of skull and mandible, both of joint discs, temporomandibular capsules and ligaments and dental arches were meshed as separate bodies. The volume meshes were transferred to the FE analysis software (FORGE(®)). Material properties were assigned for each region. Boundary conditions for closing jaw simulations were represented by different load directions of jaws muscles. The von Mises stresses distribution in both joint discs during closing conditions was analyzed. The pattern of von Mises stresses in the TMJ discs is non-symmetric and changed continuously during jaw movement. Maximal stress is reached on the surface disc in areas in contact with others bodies. The three-dimension finite element model of masticatory system will make it possible to simulate different conditions that appear to be important in the cascade of events leading to joint damage.

Predicting tibiotalar and subtalar joint angles from skin-marker data with dual-fluoroscopy as a reference standard.

PubMed

Nichols, Jennifer A; Roach, Koren E; Fiorentino, Niccolo M; Anderson, Andrew E

2016-09-01

Evidence suggests that the tibiotalar and subtalar joints provide near six degree-of-freedom (DOF) motion. Yet, kinematic models frequently assume one DOF at each of these joints. In this study, we quantified the accuracy of kinematic models to predict joint angles at the tibiotalar and subtalar joints from skin-marker data. Models included 1 or 3 DOF at each joint. Ten asymptomatic subjects, screened for deformities, performed 1.0m/s treadmill walking and a balanced, single-leg heel-rise. Tibiotalar and subtalar joint angles calculated by inverse kinematics for the 1 and 3 DOF models were compared to those measured directly in vivo using dual-fluoroscopy. Results demonstrated that, for each activity, the average error in tibiotalar joint angles predicted by the 1 DOF model were significantly smaller than those predicted by the 3 DOF model for inversion/eversion and internal/external rotation. In contrast, neither model consistently demonstrated smaller errors when predicting subtalar joint angles. Additionally, neither model could accurately predict discrete angles for the tibiotalar and subtalar joints on a per-subject basis. Differences between model predictions and dual-fluoroscopy measurements were highly variable across subjects, with joint angle errors in at least one rotation direction surpassing 10° for 9 out of 10 subjects. Our results suggest that both the 1 and 3 DOF models can predict trends in tibiotalar joint angles on a limited basis. However, as currently implemented, neither model can predict discrete tibiotalar or subtalar joint angles for individual subjects. Inclusion of subject-specific attributes may improve the accuracy of these models. Copyright © 2016 Elsevier B.V. All rights reserved.

Measurement of Laser Weld Temperatures for 3D Model Input

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagel, Daryl; Grossetete, Grant; Maccallum, Danny O.

Laser welding is a key joining process used extensively in the manufacture and assembly of critical components for several weapons systems. Sandia National Laboratories advances the understanding of the laser welding process through coupled experimentation and modeling. This report summarizes the experimental portion of the research program, which focused on measuring temperatures and thermal history of laser welds on steel plates. To increase confidence in measurement accuracy, researchers utilized multiple complementary techniques to acquire temperatures during laser welding. This data serves as input to and validation of 3D laser welding models aimed at predicting microstructure and the formation of defectsmore » and their impact on weld-joint reliability, a crucial step in rapid prototyping of weapons components.« less

3D FSE Cube and VIPR-aTR 3.0 Tesla magnetic resonance imaging predicts canine cranial cruciate ligament structural properties.

PubMed

Racette, Molly; Al saleh, Habib; Waller, Kenneth R; Bleedorn, Jason A; McCabe, Ronald P; Vanderby, Ray; Markel, Mark D; Brounts, Sabrina H; Block, Walter F; Muir, Peter

2016-03-01

Estimation of cranial cruciate ligament (CrCL) structural properties in client-owned dogs with incipient cruciate rupture would be advantageous. The objective of this study was to determine whether magnetic resonance imaging (MRI) measurement of normal CrCL volume in an ex-vivo canine model predicts structural properties. Stifles from eight dogs underwent 3.0 Tesla 3D MRI. CrCL volume and normalized median grayscale values were determined using 3D Fast Spin Echo (FSE) Cube and Vastly under-sampled Isotropic PRojection (VIPR)-alternative repetition time (aTR) sequences. Stifles were then mechanically tested. After joint laxity testing, CrCL structural properties were determined, including displacement at yield, yield load, load to failure, and stiffness. Yield load and load to failure (R(2)=0.56, P <0.01) were correlated with CrCL volume determined by VIPR-aTR. Yield load was also correlated with CrCL volume determined by 3D FSE Cube (R(2)=0.32, P <0.05). Structural properties were not related to median grayscale values. Joint laxity and CrCL stiffness were not related to MRI parameters, but displacement at yield load was related to CrCL volume for both sequences during testing (R(2)>0.57, P <0.005). In conclusion, 3D MRI offers a predictive method for estimating canine CrCL structural properties. 3D MRI may be useful for monitoring CrCL properties in clinical trials. Copyright © 2016 Elsevier Ltd. All rights reserved.

3D bioprinting: improving in vitro models of metastasis with heterogeneous tumor microenvironments

PubMed Central

Albritton, Jacob L.

2017-01-01

ABSTRACT Even with many advances in treatment over the past decades, cancer still remains a leading cause of death worldwide. Despite the recognized relationship between metastasis and increased mortality rate, surprisingly little is known about the exact mechanism of metastatic progression. Currently available in vitro models cannot replicate the three-dimensionality and heterogeneity of the tumor microenvironment sufficiently to recapitulate many of the known characteristics of tumors in vivo. Our understanding of metastatic progression would thus be boosted by the development of in vitro models that could more completely capture the salient features of cancer biology. Bioengineering groups have been working for over two decades to create in vitro microenvironments for application in regenerative medicine and tissue engineering. Over this time, advances in 3D printing technology and biomaterials research have jointly led to the creation of 3D bioprinting, which has improved our ability to develop in vitro models with complexity approaching that of the in vivo tumor microenvironment. In this Review, we give an overview of 3D bioprinting methods developed for tissue engineering, which can be directly applied to constructing in vitro models of heterogeneous tumor microenvironments. We discuss considerations and limitations associated with 3D printing and highlight how these advances could be harnessed to better model metastasis and potentially guide the development of anti-cancer strategies. PMID:28067628

3D bioprinting: improving in vitro models of metastasis with heterogeneous tumor microenvironments.

PubMed

Albritton, Jacob L; Miller, Jordan S

2017-01-01

Even with many advances in treatment over the past decades, cancer still remains a leading cause of death worldwide. Despite the recognized relationship between metastasis and increased mortality rate, surprisingly little is known about the exact mechanism of metastatic progression. Currently available in vitro models cannot replicate the three-dimensionality and heterogeneity of the tumor microenvironment sufficiently to recapitulate many of the known characteristics of tumors in vivo Our understanding of metastatic progression would thus be boosted by the development of in vitro models that could more completely capture the salient features of cancer biology. Bioengineering groups have been working for over two decades to create in vitro microenvironments for application in regenerative medicine and tissue engineering. Over this time, advances in 3D printing technology and biomaterials research have jointly led to the creation of 3D bioprinting, which has improved our ability to develop in vitro models with complexity approaching that of the in vivo tumor microenvironment. In this Review, we give an overview of 3D bioprinting methods developed for tissue engineering, which can be directly applied to constructing in vitro models of heterogeneous tumor microenvironments. We discuss considerations and limitations associated with 3D printing and highlight how these advances could be harnessed to better model metastasis and potentially guide the development of anti-cancer strategies. © 2017. Published by The Company of Biologists Ltd.

Assessment of inlet efficiency through a 3D simulation: numerical and experimental comparison.

PubMed

Gómez, Manuel; Recasens, Joan; Russo, Beniamino; Martínez-Gomariz, Eduardo

2016-10-01

Inlet efficiency is a requirement for characterizing the flow transfers between surface and sewer flow during rain events. The dual drainage approach is based on the joint analysis of both upper and lower drainage levels, and the flow transfer is one of the relevant elements to define properly this joint behaviour. This paper presents the results of an experimental and numerical investigation about the inlet efficiency definition. A full scale (1:1) test platform located in the Technical University of Catalonia (UPC) reproduces both the runoff process in streets and the water entering the inlet. Data from tests performed on this platform allow the inlet efficiency to be estimated as a function of significant hydraulic and geometrical parameters. A reproduction of these tests through a numerical three-dimensional code (Flow-3D) has been carried out simulating this type of flow by solving the RANS equations. The aim of the work was to reproduce the hydraulic performance of a previously tested grated inlet under several flow and geometric conditions using Flow-3D as a virtual laboratory. This will allow inlet efficiencies to be obtained without previous experimental tests. Moreover, the 3D model allows a better understanding of the hydraulics of the flow interception and the flow patterns approaching the inlet.

Predicting the mixed-mode I/II spatial damage propagation along 3D-printed soft interfacial layer via a hyperelastic softening model

NASA Astrophysics Data System (ADS)

Liu, Lei; Li, Yaning

2018-07-01

A methodology was developed to use a hyperelastic softening model to predict the constitutive behavior and the spatial damage propagation of nonlinear materials with damage-induced softening under mixed-mode loading. A user subroutine (ABAQUS/VUMAT) was developed for numerical implementation of the model. 3D-printed wavy soft rubbery interfacial layer was used as a material system to verify and validate the methodology. The Arruda - Boyce hyperelastic model is incorporated with the softening model to capture the nonlinear pre-and post- damage behavior of the interfacial layer under mixed Mode I/II loads. To characterize model parameters of the 3D-printed rubbery interfacial layer, a series of scarf-joint specimens were designed, which enabled systematic variation of stress triaxiality via a single geometric parameter, the slant angle. It was found that the important model parameter m is exponentially related to the stress triaxiality. Compact tension specimens of the sinusoidal wavy interfacial layer with different waviness were designed and fabricated via multi-material 3D printing. Finite element (FE) simulations were conducted to predict the spatial damage propagation of the material within the wavy interfacial layer. Compact tension experiments were performed to verify the model prediction. The results show that the model developed is able to accurately predict the damage propagation of the 3D-printed rubbery interfacial layer under complicated stress-state without pre-defined failure criteria.

Genome-wide interaction with the insulin secretion locus MTNR1B reveals CMIP as a novel type 2 diabetes susceptibility gene in African Americans.

PubMed

Keaton, Jacob M; Gao, Chuan; Guan, Meijian; Hellwege, Jacklyn N; Palmer, Nicholette D; Pankow, James S; Fornage, Myriam; Wilson, James G; Correa, Adolfo; Rasmussen-Torvik, Laura J; Rotter, Jerome I; Chen, Yii-Der I; Taylor, Kent D; Rich, Stephen S; Wagenknecht, Lynne E; Freedman, Barry I; Ng, Maggie C Y; Bowden, Donald W

2018-04-24

Although type 2 diabetes (T2D) results from metabolic defects in insulin secretion and insulin sensitivity, most of the genetic risk loci identified to date relates to insulin secretion. We reported that T2D loci influencing insulin sensitivity may be identified through interactions with insulin secretion loci, thereby leading to T2D. Here, we hypothesize that joint testing of variant main effects and interaction effects with an insulin secretion locus increases power to identify genetic interactions leading to T2D. We tested this hypothesis with an intronic MTNR1B SNP, rs10830963, which is associated with acute insulin response to glucose, a dynamic measure of insulin secretion. rs10830963 was tested for interaction and joint (main + interaction) effects with genome-wide data in African Americans (2,452 cases and 3,772 controls) from five cohorts. Genome-wide genotype data (Affymetrix Human Genome 6.0 array) was imputed to a 1000 Genomes Project reference panel. T2D risk was modeled using logistic regression with rs10830963 dosage, age, sex, and principal component as predictors. Joint effects were captured using the Kraft two degrees of freedom test. Genome-wide significant (P < 5 × 10 -8 ) interaction with MTNR1B and joint effects were detected for CMIP intronic SNP rs17197883 (P interaction  = 1.43 × 10 -8 ; P joint  = 4.70 × 10 -8 ). CMIP variants have been nominally associated with T2D, fasting glucose, and adiponectin in individuals of East Asian ancestry, with high-density lipoprotein, and with waist-to-hip ratio adjusted for body mass index in Europeans. These data support the hypothesis that additional genetic factors contributing to T2D risk, including insulin sensitivity loci, can be identified through interactions with insulin secretion loci. © 2018 WILEY PERIODICALS, INC.

Effect of increased pushoff during gait on hip joint forces

PubMed Central

Lewis, Cara L.; Garibay, Erin J.

2014-01-01

Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to “push more with your foot when you walk”. We collected motion data of markers placed on the subjects’ trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual 3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to “push more with your foot when you walk” reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces was 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain. PMID:25468661

Effect of increased pushoff during gait on hip joint forces.

PubMed

Lewis, Cara L; Garibay, Erin J

2015-01-02

Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to "push more with your foot when you walk". We collected motion data of markers placed on the subjects' trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to "push more with your foot when you walk" reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces were 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Strength and Performance Enhancement of Bonded Joints by Spatial Tailoring of Adhesive Compliance via 3D Printing.

PubMed

Kumar, S; Wardle, Brian L; Arif, Muhamad F

2017-01-11

Adhesive bonding continues to emerge as a preferred route for joining materials with broad applications including advanced structures, microelectronics, biomedical systems, and consumer goods. Here, we study the mechanics of deformation and failure of tensile-loaded single-lap joints with a compliance-tailored adhesive. Tailoring of the adhesive compliance redistributes stresses and strains to reduce both shear and peel concentrations at the ends of the adhesive that determine failure of the joint. Utilizing 3D printing, the modulus of the adhesive is spatially varied along the bondlength. Experimental strength testing, including optical strain mapping, reveals that the strain redistribution results in a greater than 100% increase in strength and toughness concomitant with a 50% increase in strain-to-break while maintaining joint stiffness. The tailoring demonstrated here is immediately realizable in a broad array of 3D printing applications, and the level of performance enhancement suggests that compliance tailoring of the adhesive is a generalizable route for achieving superior performance of joints in other applications, such as advanced structural composites.

Towards disparity joint upsampling for robust stereoscopic endoscopic scene reconstruction in robotic prostatectomy

NASA Astrophysics Data System (ADS)

Luo, Xiongbiao; McLeod, A. Jonathan; Jayarathne, Uditha L.; Pautler, Stephen E.; Schlacta, Christopher M.; Peters, Terry M.

2016-03-01

Three-dimensional (3-D) scene reconstruction from stereoscopic binocular laparoscopic videos is an effective way to expand the limited surgical field and augment the structure visualization of the organ being operated in minimally invasive surgery. However, currently available reconstruction approaches are limited by image noise, occlusions, textureless and blurred structures. In particular, an endoscope inside the body only has the limited light source resulting in illumination non-uniformities in the visualized field. These limitations unavoidably deteriorate the stereo image quality and hence lead to low-resolution and inaccurate disparity maps, resulting in blurred edge structures in 3-D scene reconstruction. This paper proposes an improved stereo correspondence framework that integrates cost-volume filtering with joint upsampling for robust disparity estimation. Joint bilateral upsampling, joint geodesic upsampling, and tree filtering upsampling were compared to enhance the disparity accuracy. The experimental results demonstrate that joint upsampling provides an effective way to boost the disparity estimation and hence to improve the surgical endoscopic scene 3-D reconstruction. Moreover, the bilateral upsampling generally outperforms the other two upsampling methods in disparity estimation.

[Registration and 3D rendering of serial tissue section images].

PubMed

Liu, Zhexing; Jiang, Guiping; Dong, Wu; Zhang, Yu; Xie, Xiaomian; Hao, Liwei; Wang, Zhiyuan; Li, Shuxiang

2002-12-01

It is an important morphological research method to reconstruct the 3D imaging from serial section tissue images. Registration of serial images is a key step to 3D reconstruction. Firstly, an introduction to the segmentation-counting registration algorithm is presented, which is based on the joint histogram. After thresholding of the two images to be registered, the criterion function is defined as counting in a specific region of the joint histogram, which greatly speeds up the alignment process. Then, the method is used to conduct the serial tissue image matching task, and lies a solid foundation for 3D rendering. Finally, preliminary surface rendering results are presented.

Variational Iterative Refinement Source Term Estimation Algorithm Assessment for Rural and Urban Environments

NASA Astrophysics Data System (ADS)

Delle Monache, L.; Rodriguez, L. M.; Meech, S.; Hahn, D.; Betancourt, T.; Steinhoff, D.

2016-12-01

It is necessary to accurately estimate the initial source characteristics in the event of an accidental or intentional release of a Chemical, Biological, Radiological, or Nuclear (CBRN) agent into the atmosphere. The accurate estimation of the source characteristics are important because many times they are unknown and the Atmospheric Transport and Dispersion (AT&D) models rely heavily on these estimates to create hazard assessments. To correctly assess the source characteristics in an operational environment where time is critical, the National Center for Atmospheric Research (NCAR) has developed a Source Term Estimation (STE) method, known as the Variational Iterative Refinement STE algorithm (VIRSA). VIRSA consists of a combination of modeling systems. These systems include an AT&D model, its corresponding STE model, a Hybrid Lagrangian-Eulerian Plume Model (H-LEPM), and its mathematical adjoint model. In an operational scenario where we have information regarding the infrastructure of a city, the AT&D model used is the Urban Dispersion Model (UDM) and when using this model in VIRSA we refer to the system as uVIRSA. In all other scenarios where we do not have the city infrastructure information readily available, the AT&D model used is the Second-order Closure Integrated PUFF model (SCIPUFF) and the system is referred to as sVIRSA. VIRSA was originally developed using SCIPUFF 2.4 for the Defense Threat Reduction Agency and integrated into the Hazard Prediction and Assessment Capability and Joint Program for Information Systems Joint Effects Model. The results discussed here are the verification and validation of the upgraded system with SCIPUFF 3.0 and the newly implemented UDM capability. To verify uVIRSA and sVIRSA, synthetic concentration observation scenarios were created in urban and rural environments and the results of this verification are shown. Finally, we validate the STE performance of uVIRSA using scenarios from the Joint Urban 2003 (JU03) experiment, which was held in Oklahoma City and also validate the performance of sVIRSA using scenarios from the FUsing Sensor Integrated Observing Network (FUSION) Field Trial 2007 (FFT07), held at Dugway Proving Grounds in rural Utah.

The EIT- and N- joint resonance lineshape asymmetry

NASA Astrophysics Data System (ADS)

Crescimanno, Michael; Hancox, Cindy; Hohensee, Michael; Phillips, David; Walsworth, Ron

2008-03-01

The solution of a quantum optics model for the joint EIT- and N- resonance explains the experimentally observed two-photon lineshape asymmetry as arising from interference and AC stark effects. This solution is evaluated for various light field intensities, detunings and couplings associated with experiments performed on the D1 and D2 transition of 87Rb. Because of its contribution to clock instability, lineshape asymmetry remains perhaps the main impediment to improving all-optical time standards based on the joint resonance.

Three-dimensional reconstructions come to life--interactive 3D PDF animations in functional morphology.

PubMed

van de Kamp, Thomas; dos Santos Rolo, Tomy; Vagovič, Patrik; Baumbach, Tilo; Riedel, Alexander

2014-01-01

Digital surface mesh models based on segmented datasets have become an integral part of studies on animal anatomy and functional morphology; usually, they are published as static images, movies or as interactive PDF files. We demonstrate the use of animated 3D models embedded in PDF documents, which combine the advantages of both movie and interactivity, based on the example of preserved Trigonopterus weevils. The method is particularly suitable to simulate joints with largely deterministic movements due to precise form closure. We illustrate the function of an individual screw-and-nut type hip joint and proceed to the complex movements of the entire insect attaining a defence position. This posture is achieved by a specific cascade of movements: Head and legs interlock mutually and with specific features of thorax and the first abdominal ventrite, presumably to increase the mechanical stability of the beetle and to maintain the defence position with minimal muscle activity. The deterministic interaction of accurately fitting body parts follows a defined sequence, which resembles a piece of engineering.

Three-Dimensional Reconstructions Come to Life – Interactive 3D PDF Animations in Functional Morphology

PubMed Central

van de Kamp, Thomas; dos Santos Rolo, Tomy; Vagovič, Patrik; Baumbach, Tilo; Riedel, Alexander

2014-01-01

Digital surface mesh models based on segmented datasets have become an integral part of studies on animal anatomy and functional morphology; usually, they are published as static images, movies or as interactive PDF files. We demonstrate the use of animated 3D models embedded in PDF documents, which combine the advantages of both movie and interactivity, based on the example of preserved Trigonopterus weevils. The method is particularly suitable to simulate joints with largely deterministic movements due to precise form closure. We illustrate the function of an individual screw-and-nut type hip joint and proceed to the complex movements of the entire insect attaining a defence position. This posture is achieved by a specific cascade of movements: Head and legs interlock mutually and with specific features of thorax and the first abdominal ventrite, presumably to increase the mechanical stability of the beetle and to maintain the defence position with minimal muscle activity. The deterministic interaction of accurately fitting body parts follows a defined sequence, which resembles a piece of engineering. PMID:25029366

A case study to quantify prediction bounds caused by model-form uncertainty of a portal frame

NASA Astrophysics Data System (ADS)

Van Buren, Kendra L.; Hall, Thomas M.; Gonzales, Lindsey M.; Hemez, François M.; Anton, Steven R.

2015-01-01

Numerical simulations, irrespective of the discipline or application, are often plagued by arbitrary numerical and modeling choices. Arbitrary choices can originate from kinematic assumptions, for example the use of 1D beam, 2D shell, or 3D continuum elements, mesh discretization choices, boundary condition models, and the representation of contact and friction in the simulation. This work takes a step toward understanding the effect of arbitrary choices and model-form assumptions on the accuracy of numerical predictions. The application is the simulation of the first four resonant frequencies of a one-story aluminum portal frame structure under free-free boundary conditions. The main challenge of the portal frame structure resides in modeling the joint connections, for which different modeling assumptions are available. To study this model-form uncertainty, and compare it to other types of uncertainty, two finite element models are developed using solid elements, and with differing representations of the beam-to-column and column-to-base plate connections: (i) contact stiffness coefficients or (ii) tied nodes. Test-analysis correlation is performed to compare the lower and upper bounds of numerical predictions obtained from parametric studies of the joint modeling strategies to the range of experimentally obtained natural frequencies. The approach proposed is, first, to characterize the experimental variability of the joints by varying the bolt torque, method of bolt tightening, and the sequence in which the bolts are tightened. The second step is to convert what is learned from these experimental studies to models that "envelope" the range of observed bolt behavior. We show that this approach, that combines small-scale experiments, sensitivity analysis studies, and bounding-case models, successfully produces lower and upper bounds of resonant frequency predictions that match those measured experimentally on the frame structure. (Approved for unlimited, public release, LA-UR-13-27561).

The effectiveness of 3D animations to enhance understanding of cranial cruciate ligament rupture.

PubMed

Clements, Dylan N; Broadhurst, Henry; Clarke, Stephen P; Farrell, Michael; Bennett, David; Mosley, John R; Mellanby, Richard J

2013-01-01

Cranial cruciate ligament (CCL) rupture is one of the most important orthopedic diseases taught to veterinary undergraduates. The complexity of the anatomy of the canine stifle joint combined with the plethora of different surgical interventions available for the treatment of the disease means that undergraduate veterinary students often have a poor understanding of the pathophysiology and treatment of CCL rupture. We designed, developed, and tested a three dimensional (3D) animation to illustrate the pertinent clinical anatomy of the stifle joint, the effects of CCL rupture, and the mechanisms by which different surgical techniques can stabilize the joint with CCL rupture. When compared with a non-animated 3D presentation, students' short-term retention of functional anatomy improved although they could not impart a better explanation of how different surgical techniques worked. More students found the animation useful than those who viewed a comparable non-animated 3D presentation. Multiple peer-review testing is required to maximize the usefulness of 3D animations during development. Free and open access to such tools should improve student learning and client understanding through wide-spread uptake and use.

Empirical Assessment of the Mean Block Volume of Rock Masses Intersected by Four Joint Sets

NASA Astrophysics Data System (ADS)

Morelli, Gian Luca

2016-05-01

The estimation of a representative value for the rock block volume ( V b) is of huge interest in rock engineering in regards to rock mass characterization purposes. However, while mathematical relationships to precisely estimate this parameter from the spacing of joints can be found in literature for rock masses intersected by three dominant joint sets, corresponding relationships do not actually exist when more than three sets occur. In these cases, a consistent assessment of V b can only be achieved by directly measuring the dimensions of several representative natural rock blocks in the field or by means of more sophisticated 3D numerical modeling approaches. However, Palmström's empirical relationship based on the volumetric joint count J v and on a block shape factor β is commonly used in the practice, although strictly valid only for rock masses intersected by three joint sets. Starting from these considerations, the present paper is primarily intended to investigate the reliability of a set of empirical relationships linking the block volume with the indexes most commonly used to characterize the degree of jointing in a rock mass (i.e. the J v and the mean value of the joint set spacings) specifically applicable to rock masses intersected by four sets of persistent discontinuities. Based on the analysis of artificial 3D block assemblies generated using the software AutoCAD, the most accurate best-fit regression has been found between the mean block volume (V_{{{{b}}_{{m}} }}) of tested rock mass samples and the geometric mean value of the spacings of the joint sets delimiting blocks; thus, indicating this mean value as a promising parameter for the preliminary characterization of the block size. Tests on field outcrops have demonstrated that the proposed empirical methodology has the potential of predicting the mean block volume of multiple-set jointed rock masses with an acceptable accuracy for common uses in most practical rock engineering applications.

A computational model of the human hand 93-ERI-053

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollerbach, K.; Axelrod, T.

1996-03-01

The objectives of the Computational Hand Modeling project were to prove the feasibility of the Laboratory`s NIKE3D finite element code to orthopaedic problems. Because of the great complexity of anatomical structures and the nonlinearity of their behavior, we have focused on a subset of joints of the hand and lower extremity and have developed algorithms to model their behavior. The algorithms developed here solve fundamental problems in computational biomechanics and can be expanded to describe any other joints of the human body. This kind of computational modeling has never successfully been attempted before, due in part to a lack ofmore » biomaterials data and a lack of computational resources. With the computational resources available at the National Laboratories and the collaborative relationships we have established with experimental and other modeling laboratories, we have been in a position to pursue our innovative approach to biomechanical and orthopedic modeling.« less

Wedge Experiment Modeling and Simulation for Reactive Flow Model Calibration

NASA Astrophysics Data System (ADS)

Maestas, Joseph T.; Dorgan, Robert J.; Sutherland, Gerrit T.

2017-06-01

Wedge experiments are a typical method for generating pop-plot data (run-to-detonation distance versus input shock pressure), which is used to assess an explosive material's initiation behavior. Such data can be utilized to calibrate reactive flow models by running hydrocode simulations and successively tweaking model parameters until a match between experiment is achieved. Typical simulations are performed in 1D and typically use a flyer impact to achieve the prescribed shock loading pressure. In this effort, a wedge experiment performed at the Army Research Lab (ARL) was modeled using CTH (SNL hydrocode) in 1D, 2D, and 3D space in order to determine if there was any justification in using simplified models. A simulation was also performed using the BCAT code (CTH companion tool) that assumes a plate impact shock loading. Results from the simulations were compared to experimental data and show that the shock imparted into an explosive specimen is accurately captured with 2D and 3D simulations, but changes significantly in 1D space and with the BCAT tool. The difference in shock profile is shown to only affect numerical predictions for large run distances. This is attributed to incorrectly capturing the energy fluence for detonation waves versus flat shock loading. Portions of this work were funded through the Joint Insensitive Munitions Technology Program.

Application of three-dimensional rendering in joint-related ganglion cysts.

PubMed

Spinner, Robert J; Edwards, Phillip K; Amrami, Kimberly K

2006-05-01

The origin of para-articular cysts is poorly understood and controversial. The relatively common, simple (extraneural) cysts are presumed to be derived from joints, although joint connections are not always established. Rarer complex cysts are thought by many to form de novo within nerves (intraneural ganglion cysts) or within vessels (adventitial cysts) (degenerative theory). We believe that these simple and complex ganglion cysts are joint-related (articular theory). Joint connections are often not readily appreciated with routine imaging or at surgery. Not identifying and/or treating joint connections frequently leads to cyst recurrence. More sophisticated imaging may enhance visualization of these joint connections. We created a 3D rendering technique to assess potential joint connections of simple and complex cysts localized to the knee and superior tibiofibular joints in patients with fibular (peroneal) neuropathy. Two- and three-dimensional data sets from MRI examinations were segmented semiautomatically by signal intensity with further refinement based on interaction with the user to identify specific anatomic structures, such as small nerves and vessels on serial images. The bone, cysts, nerves, and vessels were each assigned different color representations, and 3D renderings were created in ANALYZE using the data sets closest to isotropic (voxel with equal length in all dimensions) resolution as the primary background rendering. We selected four cases to illustrate the spectrum of pathology. In all of these cases, we demonstrated joint connections and correlated imaging and operative findings. Surgery addressing the cyst and the joint connection resulted in excellent outcomes; postoperative MRIs done more than 6 months later confirmed that there was no recurrence. In addition to highlighting the important relationship of these cysts to neighboring anatomic structures, this 3D technique allows visualization of "occult" connections not readily appreciated with standard MR imaging. We believe that these joint-related cysts have a common pathogenesis; they dissect through a capsular rent and follow the path of least resistance; they may form simple cysts by dissecting out into the soft tissue, or more complex cysts by dissecting within the epineurium of nerves or adventitia of vessels (along an articular branch), or various combinations of all of these types of cysts. Understanding the pathogenesis for cyst formation will improve surgical management and outcomes. We have adapted this 3D technique to enhance the visualization of cysts occurring at other joints.

Influence of dendritic polyglycerol sulfates on knee osteoarthritis: an experimental study in the rat osteoarthritis model.

PubMed

Schneider, Tobias; Welker, Pia; Licha, Kai; Haag, Rainer; Schulze-Tanzil, Gundula

2015-12-15

Anti-inflammatory nanoparticular compounds could represent a strategy to diminish osteoarthritis (OA) progression. The present study was undertaken to prove the uptake of nanoparticular dendritic polyglycerol sulfates (dPGS) by rat-derived articular chondrocytes and to answer the question of whether dPGS could modulate knee joint cartilage degradation in a rat OA model and whether complications could arise. dPGS uptake and cytotoxicity was assessed in cultured primary rat-derived articular chondrocytes. Subsequently, OA was induced in the right knee joints of 12 male Wistar rats by medial collateral ligament and meniscus transection. Unoperated left knees remained as controls. Six weeks post surgery six rats were either treated daily (14 days) with 30 mg/kg dPGS (s.c.) or a similar volume of physiological saline. Animals were analyzed clinically for gait alterations. Explanted knee joints were studied histologically using OA scores according to Mankin (1971), Glasson et al., (2010) and the synovitis score according to Krenn et al., (2006). Liver, spleen and kidneys were analyzed for degenerative changes due to dPGS accumulation. dPGS was taken up after 2 hours by the chondrocytes. Whereas no significant clinical signs of OA could be detected, at the histological level, all operated rat knee joints revealed features of OA in the medial compartment. The values produced by both OA score systems were lower in rats treated with dPGS compared with saline-treated animals. Synovitis score did not significantly differ between the groups. The analyzed organs revealed no degenerative changes. dPGS presented overall cyto- and biocompatibility, no accumulation in metabolizing organs and chondroprotective properties in the osteoarthritic knee joint.

Gender dimorphic ACL strain in response to combined dynamic 3D knee joint loading: implications for ACL injury risk.

PubMed

Mizuno, Kiyonori; Andrish, Jack T; van den Bogert, Antonie J; McLean, Scott G

2009-12-01

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (approximately 10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as a function of the combined 6 DOF knee loads. Following individual model verifications, generalized gender-specific models were generated and subjected to 6 DOF external load scenarios consistent with both a clinical examination and a dynamic sports maneuver. The ensuing model-based strain predictions were subsequently examined for gender-based discrepancies. Male and female specimen-specific models predicted ACL strain within 0.51%+/-0.10% and 0.52%+/-0.07% of the measured data respectively, and explained more than 75% of the associated variance in each case. Predicted female ACL strains were also significantly larger than respective male values for both simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities.

A Method of Accurate Bone Tunnel Placement for Anterior Cruciate Ligament Reconstruction Based on 3-Dimensional Printing Technology: A Cadaveric Study.

PubMed

Ni, Jianlong; Li, Dichen; Mao, Mao; Dang, Xiaoqian; Wang, Kunzheng; He, Jiankang; Shi, Zhibin

2018-02-01

To explore a method of bone tunnel placement for anterior cruciate ligament (ACL) reconstruction based on 3-dimensional (3D) printing technology and to assess its accuracy. Twenty human cadaveric knees were scanned by thin-layer computed tomography (CT). To obtain data on bones used to establish a knee joint model by computer software, customized bone anchors were installed before CT. The reference point was determined at the femoral and tibial footprint areas of the ACL. The site and direction of the bone tunnels of the femur and tibia were designed and calibrated on the knee joint model according to the reference point. The resin template was designed and printed by 3D printing. Placement of the bone tunnels was accomplished by use of templates, and the cadaveric knees were scanned again to compare the concordance of the internal opening of the bone tunnels and reference points. The twenty 3D printing templates were designed and printed successfully. CT data analysis between the planned and actual drilled tunnel positions showed mean deviations of 0.57 mm (range, 0-1.5 mm; standard deviation, 0.42 mm) at the femur and 0.58 mm (range, 0-1.5 mm; standard deviation, 0.47 mm) at the tibia. The accuracy of bone tunnel placement for ACL reconstruction in cadaveric adult knees based on 3D printing technology is high. This method can improve the accuracy of bone tunnel placement for ACL reconstruction in clinical sports medicine. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Is 3D true non linear traveltime tomography reasonable ?

NASA Astrophysics Data System (ADS)

Herrero, A.; Virieux, J.

2003-04-01

The data sets requiring 3D analysis tools in the context of seismic exploration (both onshore and offshore experiments) or natural seismicity (micro seismicity surveys or post event measurements) are more and more numerous. Classical linearized tomographies and also earthquake localisation codes need an accurate 3D background velocity model. However, if the medium is complex and a priori information not available, a 1D analysis is not able to provide an adequate background velocity image. Moreover, the design of the acquisition layouts is often intrinsically 3D and renders difficult even 2D approaches, especially in natural seismicity cases. Thus, the solution relies on the use of a 3D true non linear approach, which allows to explore the model space and to identify an optimal velocity image. The problem becomes then practical and its feasibility depends on the available computing resources (memory and time). In this presentation, we show that facing a 3D traveltime tomography problem with an extensive non-linear approach combining fast travel time estimators based on level set methods and optimisation techniques such as multiscale strategy is feasible. Moreover, because management of inhomogeneous inversion parameters is more friendly in a non linear approach, we describe how to perform a jointly non-linear inversion for the seismic velocities and the sources locations.

Calibration of 3D ALE finite element model from experiments on friction stir welding of lap joints

NASA Astrophysics Data System (ADS)

Fourment, Lionel; Gastebois, Sabrina; Dubourg, Laurent

2016-10-01

In order to support the design of such a complex process like Friction Stir Welding (FSW) for the aeronautic industry, numerical simulation software requires (1) developing an efficient and accurate Finite Element (F.E.) formulation that allows predicting welding defects, (2) properly modeling the thermo-mechanical complexity of the FSW process and (3) calibrating the F.E. model from accurate measurements from FSW experiments. This work uses a parallel ALE formulation developed in the Forge® F.E. code to model the different possible defects (flashes and worm holes), while pin and shoulder threads are modeled by a new friction law at the tool / material interface. FSW experiments require using a complex tool with scroll on shoulder, which is instrumented for providing sensitive thermal data close to the joint. Calibration of unknown material thermal coefficients, constitutive equations parameters and friction model from measured forces, torques and temperatures is carried out using two F.E. models, Eulerian and ALE, to reach a satisfactory agreement assessed by the proper sensitivity of the simulation to process parameters.

Sandia/Stanford Unified Creep Plasticity Damage Model for ANSYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, David M.; Vianco, Paul T.; Fossum, Arlo F.

2006-09-03

A unified creep plasticity (UCP) model was developed, based upon the time-dependent and time-independent deformation properties of the 95.5Sn-3.9Ag-0.6Cu (wt.%) soldier that were measured at Sandia. Then, a damage parameter, D, was added to the equation to develop the unified creep plasticity damage (UCPD) model. The parameter, D, was parameterized, using data obtained at Sandia from isothermal fatigue experiments on a double-lap shear test. The softwae was validated against a BGA solder joint exposed to thermal cycling. The UCPD model was put into the ANSYS finite element as a subroutine. So, the softwae is the subroutine for ANSYS 8.1.

Density Imaging of Puy de Dôme Volcano by Joint Inversion of Muographic and Gravimetric Data

NASA Astrophysics Data System (ADS)

Barnoud, A.; Niess, V.; Le Ménédeu, E.; Cayol, V.; Carloganu, C.

2016-12-01

We aim at jointly inverting high density muographic and gravimetric data to robustly infer the density structure of volcanoes. We use the puy de Dôme volcano in France as a proof of principle since high quality data sets are available for both muography and gravimetry. Gravimetric inversion and muography are independent methods that provide an estimation of density distributions. On the one hand, gravimetry allows to reconstruct 3D density variations by inversion. This process is well known to be ill-posed and intrinsically non unique, thus it requires additional constraints (eg. a priori density model). On the other hand, muography provides a direct measurement of 2D mean densities (radiographic images) from the detection of high energy atmospheric muons crossing the volcanic edifice. 3D density distributions can be computed from several radiographic images, but the number of images is generally limited by field constraints and by the limited number of available telescopes. Thus, muon tomography is also ill-posed in practice.In the case of the puy de Dôme volcano, the density structures inferred from gravimetric data (Portal et al. 2016) and from muographic data (Le Ménédeu et al. 2016) show a qualitative agreement but cannot be compared quantitatively. Because each method has different intrinsic resolutions due to the physics (Jourde et al., 2015), the joint inversion is expected to improve the robustness of the inversion. Such joint inversion has already been applied in a volcanic context (Nishiyama et al., 2013).Volcano muography requires state-of-art, high-resolution and large-scale muon detectors (Ambrosino et al., 2015). Instrumental uncertainties and systematic errors may constitute an important limitation for muography and should not be overlooked. For instance, low-energy muons are detected together with ballistic high-energy muons, decreasing the measured value of the mean density closed to the topography.Here, we jointly invert the gravimetric and muographic data to characterize the 3D density distribution of the puy de Dôme volcano. We attempt to precisely identify and estimate the different uncertainties and systematic errors so that they can be accounted for in the inversion scheme.

Using 3D Printing (Additive Manufacturing) to Produce Low-Cost Simulation Models for Medical Training.

PubMed

Lichtenberger, John P; Tatum, Peter S; Gada, Satyen; Wyn, Mark; Ho, Vincent B; Liacouras, Peter

2018-03-01

This work describes customized, task-specific simulation models derived from 3D printing in clinical settings and medical professional training programs. Simulation models/task trainers have an array of purposes and desired achievements for the trainee, defining that these are the first step in the production process. After this purpose is defined, computer-aided design and 3D printing (additive manufacturing) are used to create a customized anatomical model. Simulation models then undergo initial in-house testing by medical specialists followed by a larger scale beta testing. Feedback is acquired, via surveys, to validate effectiveness and to guide or determine if any future modifications and/or improvements are necessary. Numerous custom simulation models have been successfully completed with resulting task trainers designed for procedures, including removal of ocular foreign bodies, ultrasound-guided joint injections, nerve block injections, and various suturing and reconstruction procedures. These task trainers have been frequently utilized in the delivery of simulation-based training with increasing demand. 3D printing has been integral to the production of limited-quantity, low-cost simulation models across a variety of medical specialties. In general, production cost is a small fraction of a commercial, generic simulation model, if available. These simulation and training models are customized to the educational need and serve an integral role in the education of our military health professionals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abushakra, Bass

The aging tests conducted so far showed that duct tape tends to degrade in its performance as the joint it is applied to requires a geometrical description of a higher number of space dimensions (1-D, 2-D, 3-D). One-dimensional joints are the easiest to seal with duct tape, and thus the least to experience failure. Two-dimensional joints, such as the flexible duct core-to-collar joints tested in this study, are less likely to fail than three-dimensional collar-to-plenum joints, as the shrinkage could have a positive effect in tightening the joint. Three-dimensional joints are the toughest to seal and the most likely tomore » experience failure. The 2-D flexible duct core-to-collar joints passed the six-month period of the aging test in terms of leakage, but with the exception of the foil-butyl tape, showed degradation in terms hardening, brittleness, partial peeling, shrinkage, wrinkling, delamination of the tape layers, flaking, cracking, bubbling, oozing and discoloration. The baking test results showed that the failure in the duct tape joints could be attributed to the type of combination of the duct tape and the material it is applied to, as the duct tape behaves differently with different substrates. Overall, the foil-butyl tape (Tape 4) had the best results, while the film tape (Tape 3) showed the most deterioration. The conventional duct tapes tested (Tape 1 and Tape 2) were between these two extremes, with Tape 2 performing better than Tape 1. Lastly, we found that plastic straps became discolored and brittle during the tests, and a couple of straps broke completely. Therefore, we recommend that clamping the duct-taped flexible core-to-collar joints should be done with metallic adjustable straps.« less

East Pacific Rise axial structure from a joint tomographic inversion of traveltimes picked on downward continued and standard shot gathers collected by 3D MCS surveying

NASA Astrophysics Data System (ADS)

Newman, Kori; Nedimović, Mladen; Delescluse, Matthias; Menke, William; Canales, J. Pablo; Carbotte, Suzanne; Carton, Helene; Mutter, John

2010-05-01

We present traveltime tomographic models along closely spaced (~250 m), strike-parallel profiles that flank the axis of the East Pacific Rise at 9°41' - 9°57' N. The data were collected during a 3D (multi-streamer) multichannel seismic (MCS) survey of the ridge. Four 6-km long hydrophone streamers were towed by the ship along three along-axis sail lines, yielding twelve possible profiles over which to compute tomographic models. Based on the relative location between source-receiver midpoints and targeted subsurface structures, we have chosen to compute models for four of those lines. MCS data provide for a high density of seismic ray paths with which to constrain the model. Potentially, travel times for ~250,000 source-receiver pairs can be picked over the 30 km length of each model. However, such data density does not enhance the model resolution, so, for computational efficiency, the data are decimated so that ~15,000 picks per profile are used. Downward continuation of the shot gathers simulates an experimental geometry in which the sources and receivers are positioned just above the sea floor. This allows the shallowest sampling refracted arrivals to be picked and incorporated into the inversion whereas they would otherwise not be usable with traditional first-arrival travel-time tomographic techniques. Some of the far-offset deep-penetrating 2B refractions cannot be picked on the downward continued gathers due to signal processing artifacts. For this reason, we run a joint inversion by also including 2B traveltime picks from standard shot gathers. Uppermost velocity structure (seismic layer 2A thickness and velocity) is primarily constrained from 1D inversion of the nearest offset (<500 m) source-receiver travel-time picks for each downward continued shot gather. Deeper velocities are then computed in a joint 2D inversion that uses all picks from standard and downward continued shot gathers and incorporates the 1D results into the starting model. The resulting velocity models extend ~1 km into the crust. Preliminary results show thicker layer 2A and faster layer 2A velocities at fourth order ridge segment boundaries. Additionally, layer 2A thickens north of 9° 52' N, which is consistent with earlier investigations of this ridge segment. Slower layer 2B velocities are resolved in the vicinity of documented hydrothermal vent fields. We anticipate that additional analyses of the results will yield further insight into fine scale variations in near-axis mid-ocean ridge structure.

3D Printed Robotic Hand

NASA Technical Reports Server (NTRS)

Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

2013-01-01

Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

TeCo3D: a 3D telecooperation application based on VRML and Java

NASA Astrophysics Data System (ADS)

Mauve, Martin

1998-12-01

In this paper we present a method for sharing collaboration- unaware VRML content, e.g. 3D models which were not specifically developed for use in a distributed environment. This functionality is an essential requirement for the inclusion of arbitrary VRML content, as generated by standard CAD or animation software, into teleconferencing sessions. We have developed a 3D TeleCooperation (TeCo3D) prototype to demonstrate the feasibility of our approach. The basic services provided by the prototype are the distribution of cooperation unaware VRML content, the sharing of user interactions, and the joint viewing of the content. In order to achieve maximum portability, the prototype was developed completely in Java. This paper presents general aspects of sharing VRML content as well as the concepts, the architecture and the services of the TeCo3D prototype. Our approach relies on existing VRML browsers as the VRML presentation and execution engines while reliable multicast is used as the means of communication to provide for scalability.

Modeling 4D Pathological Changes by Leveraging Normative Models

PubMed Central

Wang, Bo; Prastawa, Marcel; Irimia, Andrei; Saha, Avishek; Liu, Wei; Goh, S.Y. Matthew; Vespa, Paul M.; Van Horn, John D.; Gerig, Guido

2016-01-01

With the increasing use of efficient multimodal 3D imaging, clinicians are able to access longitudinal imaging to stage pathological diseases, to monitor the efficacy of therapeutic interventions, or to assess and quantify rehabilitation efforts. Analysis of such four-dimensional (4D) image data presenting pathologies, including disappearing and newly appearing lesions, represents a significant challenge due to the presence of complex spatio-temporal changes. Image analysis methods for such 4D image data have to include not only a concept for joint segmentation of 3D datasets to account for inherent correlations of subject-specific repeated scans but also a mechanism to account for large deformations and the destruction and formation of lesions (e.g., edema, bleeding) due to underlying physiological processes associated with damage, intervention, and recovery. In this paper, we propose a novel framework that provides a joint segmentation-registration framework to tackle the inherent problem of image registration in the presence of objects not present in all images of the time series. Our methodology models 4D changes in pathological anatomy across time and and also provides an explicit mapping of a healthy normative template to a subject’s image data with pathologies. Since atlas-moderated segmentation methods cannot explain appearance and locality pathological structures that are not represented in the template atlas, the new framework provides different options for initialization via a supervised learning approach, iterative semisupervised active learning, and also transfer learning, which results in a fully automatic 4D segmentation method. We demonstrate the effectiveness of our novel approach with synthetic experiments and a 4D multimodal MRI dataset of severe traumatic brain injury (TBI), including validation via comparison to expert segmentations. However, the proposed methodology is generic in regard to different clinical applications requiring quantitative analysis of 4D imaging representing spatio-temporal changes of pathologies. PMID:27818606

Digital tomosynthesis rendering of joint margins for arthritis assessment

NASA Astrophysics Data System (ADS)

Duryea, Jeffrey W.; Neumann, Gesa; Yoshioka, Hiroshi; Dobbins, James T., III

2004-05-01

PURPOSE: Rheumatoid arthritis (RA) of the hand is a significant healthcare problem. Techniques to accurately quantity the structural changes from RA are crucial for the development and prescription of therapies. Analysis of radiographic joint space width (JSW) is widely used and has demonstrated promise. However, radiography presents a 2D view of the joint. In this study we performed tomosynthesis reconstructions of proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joints to measure the 3D joint structure. METHODS: We performed a reader study using simulated radiographs of 12 MCP and 12 PIP joints from skeletal specimens imaged with micro-CT. The tomosynthesis technique provided images of reconstructed planes with 0.75 mm spacing, which were presented to 2 readers with a computer tool. The readers were instructed to delineate the joint surfaces on tomosynthetic slices where they could visualize the margins. We performed a quantitative analysis of 5 slices surrounding the central portion of each joint. Reader-determined JSW was compared to a gold standard. As a figure of merit we calculated the average root-mean square deviation (RMSD). RESULTS: RMSD was 0.22 mm for both joints. For the individual joints, RMSD was 0.18 mm (MCP), and 0.26 mm (PIP). The reduced performance for the smaller PIP joints suggests that a slice spacing less than 0.75 mm may be more appropriate. CONCLUSIONS: We have demonstrated the capability of limited 3D rendering of joint surfaces using digital tomosynthesis. This technique promises to provide an improved method to visualize the structural changes of RA.

Mechanical Behavior of Dowel-Type Joints Made of Wood Scrimber Composite

PubMed Central

He, Minjuan; Tao, Duo; Li, Zheng; Li, Maolin

2016-01-01

As a renewable building material with low embodied energy characteristics, wood has gained more and more attention in the green and sustainable building industry. In terms of material resource and physical properties, scrimber composite not only makes full use of fast-growing wood species, but also has better mechanical performance and less inherent variability than natural wood material. In this study, the mechanical behavior of bolted beam-to-column joints built with a kind of scrimber composite was investigated both experimentally and numerically. Two groups of specimens were tested under monotonic and low frequency cyclic loading protocols. The experimental results showed that the bolted joints built with scrimber composite performed well in initial stiffness, ductility, and energy dissipation. A three-dimensional (3D) non-linear finite element model (FEM) for the bolted beam-to-column joints was then developed and validated by experimental results. The validated model was further used to investigate the failure mechanism of the bolted joints through stress analysis. This study can contribute to the application of the proposed scrimber composite in structural engineering, and the developed FEM can serve as a useful tool to evaluate the mechanical behavior of such bolted beam-to-column joints with different configurations in future research. PMID:28773703

Mechanical Behavior of Dowel-Type Joints Made of Wood Scrimber Composite.

PubMed

He, Minjuan; Tao, Duo; Li, Zheng; Li, Maolin

2016-07-15

As a renewable building material with low embodied energy characteristics, wood has gained more and more attention in the green and sustainable building industry. In terms of material resource and physical properties, scrimber composite not only makes full use of fast-growing wood species, but also has better mechanical performance and less inherent variability than natural wood material. In this study, the mechanical behavior of bolted beam-to-column joints built with a kind of scrimber composite was investigated both experimentally and numerically. Two groups of specimens were tested under monotonic and low frequency cyclic loading protocols. The experimental results showed that the bolted joints built with scrimber composite performed well in initial stiffness, ductility, and energy dissipation. A three-dimensional (3D) non-linear finite element model (FEM) for the bolted beam-to-column joints was then developed and validated by experimental results. The validated model was further used to investigate the failure mechanism of the bolted joints through stress analysis. This study can contribute to the application of the proposed scrimber composite in structural engineering, and the developed FEM can serve as a useful tool to evaluate the mechanical behavior of such bolted beam-to-column joints with different configurations in future research.

Wear Distribution Detection of Knee Joint Prostheses by Means of 3D Optical Scanners

PubMed Central

Affatato, Saverio; Valigi, Maria Cristina; Logozzo, Silvia

2017-01-01

The objective of this study was to examine total knee polyethylene inserts from in vitro simulation to evaluate and display—using a 3D optical scanner—wear patterns and wear rates of inserts exposed to wear by means of simulators. Various sets of tibial inserts have been reconstructed by using optical scanners. With this in mind, the wear behavior of fixed and mobile bearing polyethylene knee configurations was investigated using a knee wear joint simulator. After the completion of the wear test, the polyethylene menisci were analyzed by an innovative 3D optical scanners in order to evaluate the 3D wear distribution on the prosthesis surface. This study implemented a new procedure for evaluating polyethylene bearings of joint prostheses obtained after in vitro wear tests and the proposed new approach allowed quantification of the contact zone on the geometry of total knee prostheses. The results of the present study showed that mobile TKPs (total knee prosthesis) have lower wear resistance with respect to fixed TKPs. PMID:28772725

Root Cause Investigation of Lead-Free Solder Joint Interfacial Failures After Multiple Reflows

NASA Astrophysics Data System (ADS)

Li, Yan; Hatch, Olen; Liu, Pilin; Goyal, Deepak

2017-03-01

Solder joint interconnects in three-dimensional (3D) packages with package stacking configurations typically must undergo multiple reflow cycles during the assembly process. In this work, interfacial open joint failures between the bulk solder and the intermetallic compound (IMC) layer were found in Sn-Ag-Cu (SAC) solder joints connecting a small package to a large package after multiple reflow reliability tests. Systematic progressive 3D x-ray computed tomography experiments were performed on both incoming and assembled parts to reveal the initiation and evolution of the open failures in the same solder joints before and after the reliability tests. Characterization studies, including focused ion beam cross-sections, scanning electron microscopy, and energy-dispersive x-ray spectroscopy, were conducted to determine the correlation between IMC phase transformation and failure initiation in the solder joints. A comprehensive failure mechanism, along with solution paths for the solder joint interfacial failures after multiple reflow cycles, is discussed in detail.

Cortex Inspired Model for Inverse Kinematics Computation for a Humanoid Robotic Finger

PubMed Central

Gentili, Rodolphe J.; Oh, Hyuk; Molina, Javier; Reggia, James A.; Contreras-Vidal, José L.

2013-01-01

In order to approach human hand performance levels, artificial anthropomorphic hands/fingers have increasingly incorporated human biomechanical features. However, the performance of finger reaching movements to visual targets involving the complex kinematics of multi-jointed, anthropomorphic actuators is a difficult problem. This is because the relationship between sensory and motor coordinates is highly nonlinear, and also often includes mechanical coupling of the two last joints. Recently, we developed a cortical model that learns the inverse kinematics of a simulated anthropomorphic finger. Here, we expand this previous work by assessing if this cortical model is able to learn the inverse kinematics for an actual anthropomorphic humanoid finger having its two last joints coupled and controlled by pneumatic muscles. The findings revealed that single 3D reaching movements, as well as more complex patterns of motion of the humanoid finger, were accurately and robustly performed by this cortical model while producing kinematics comparable to those of humans. This work contributes to the development of a bioinspired controller providing adaptive, robust and flexible control of dexterous robotic and prosthetic hands. PMID:23366569

PHT3D-UZF: A reactive transport model for variably-saturated porous media

USGS Publications Warehouse

Wu, Ming Zhi; Post, Vincent E. A.; Salmon, S. Ursula; Morway, Eric D.; Prommer, H.

2016-01-01

A modified version of the MODFLOW/MT3DMS-based reactive transport model PHT3D was developed to extend current reactive transport capabilities to the variably-saturated component of the subsurface system and incorporate diffusive reactive transport of gaseous species. Referred to as PHT3D-UZF, this code incorporates flux terms calculated by MODFLOW's unsaturated-zone flow (UZF1) package. A volume-averaged approach similar to the method used in UZF-MT3DMS was adopted. The PHREEQC-based computation of chemical processes within PHT3D-UZF in combination with the analytical solution method of UZF1 allows for comprehensive reactive transport investigations (i.e., biogeochemical transformations) that jointly involve saturated and unsaturated zone processes. Intended for regional-scale applications, UZF1 simulates downward-only flux within the unsaturated zone. The model was tested by comparing simulation results with those of existing numerical models. The comparison was performed for several benchmark problems that cover a range of important hydrological and reactive transport processes. A 2D simulation scenario was defined to illustrate the geochemical evolution following dewatering in a sandy acid sulfate soil environment. Other potential applications include the simulation of biogeochemical processes in variably-saturated systems that track the transport and fate of agricultural pollutants, nutrients, natural and xenobiotic organic compounds and micropollutants such as pharmaceuticals, as well as the evolution of isotope patterns.

dPIRPLE: a joint estimation framework for deformable registration and penalized-likelihood CT image reconstruction using prior images

NASA Astrophysics Data System (ADS)

Dang, H.; Wang, A. S.; Sussman, Marc S.; Siewerdsen, J. H.; Stayman, J. W.

2014-09-01

Sequential imaging studies are conducted in many clinical scenarios. Prior images from previous studies contain a great deal of patient-specific anatomical information and can be used in conjunction with subsequent imaging acquisitions to maintain image quality while enabling radiation dose reduction (e.g., through sparse angular sampling, reduction in fluence, etc). However, patient motion between images in such sequences results in misregistration between the prior image and current anatomy. Existing prior-image-based approaches often include only a simple rigid registration step that can be insufficient for capturing complex anatomical motion, introducing detrimental effects in subsequent image reconstruction. In this work, we propose a joint framework that estimates the 3D deformation between an unregistered prior image and the current anatomy (based on a subsequent data acquisition) and reconstructs the current anatomical image using a model-based reconstruction approach that includes regularization based on the deformed prior image. This framework is referred to as deformable prior image registration, penalized-likelihood estimation (dPIRPLE). Central to this framework is the inclusion of a 3D B-spline-based free-form-deformation model into the joint registration-reconstruction objective function. The proposed framework is solved using a maximization strategy whereby alternating updates to the registration parameters and image estimates are applied allowing for improvements in both the registration and reconstruction throughout the optimization process. Cadaver experiments were conducted on a cone-beam CT testbench emulating a lung nodule surveillance scenario. Superior reconstruction accuracy and image quality were demonstrated using the dPIRPLE algorithm as compared to more traditional reconstruction methods including filtered backprojection, penalized-likelihood estimation (PLE), prior image penalized-likelihood estimation (PIPLE) without registration, and prior image penalized-likelihood estimation with rigid registration of a prior image (PIRPLE) over a wide range of sampling sparsity and exposure levels.

The 2015 Gorkha (Nepal) earthquake sequence: I. Source modeling and deterministic 3D ground shaking

NASA Astrophysics Data System (ADS)

Wei, Shengji; Chen, Meng; Wang, Xin; Graves, Robert; Lindsey, Eric; Wang, Teng; Karakaş, Çağıl; Helmberger, Don

2018-01-01

To better quantify the relatively long period (< 0.3 Hz) shaking experienced during the 2015 Gorkha (Nepal) earthquake sequence, we study the finite rupture processes and the associated 3D ground motion of the Mw7.8 mainshock and the Mw7.2 aftershock. The 3D synthetics are then used in the broadband ground shaking in Kathmandu with a hybrid approach, summarized in a companion paper (Chen and Wei, 2017, submitted together). We determined the coseismic rupture process of the mainshock by joint inversion of InSAR/SAR, GPS (static and high-rate), strong motion and teleseismic waveforms. Our inversion for the mainshock indicates unilateral rupture towards the ESE, with an average rupture speed of 3.0 km/s and a total duration of 60 s. Additionally, we find that the beginning part of the rupture (5-18 s) has about 40% longer rise time than the rest of the rupture, as well as slower rupture velocity. Our model shows two strong asperities occurring 24 s and 36 s after the origin and located 30 km to the northwest and northeast of the Kathmandu valley, respectively. In contrast, the Mw7.2 aftershock is more compact both in time and space, as revealed by joint inversion of teleseismic body waves and InSAR data. The different rupture features between the mainshock and the aftershock could be related to difference in fault zone structure. The mainshock and aftershock ground motions in the Kathmandu valley, recorded by both strong motion and high-rate GPS stations, exhibited strong amplification around 0.2 Hz. A simplified 3D basin model, calibrated by an Mw5.2 aftershock, can match the observed waveforms reasonably well at 0.3 Hz and lower frequency. The 3D simulations indicate that the basin structure trapped the wavefield and produced an extensive ground vibration. Our study suggests that the combination of rupture characteristics and propagational complexity are required to understand the ground shaking produced by hazardous earthquakes such as the Gorkha event.

Quon 3D language for quantum information

PubMed Central

Liu, Zhengwei; Wozniakowski, Alex; Jaffe, Arthur M.

2017-01-01

We present a 3D topological picture-language for quantum information. Our approach combines charged excitations carried by strings, with topological properties that arise from embedding the strings in the interior of a 3D manifold with boundary. A quon is a composite that acts as a particle. Specifically, a quon is a hemisphere containing a neutral pair of open strings with opposite charge. We interpret multiquons and their transformations in a natural way. We obtain a type of relation, a string–genus “joint relation,” involving both a string and the 3D manifold. We use the joint relation to obtain a topological interpretation of the C∗-Hopf algebra relations, which are widely used in tensor networks. We obtain a 3D representation of the controlled NOT (CNOT) gate that is considerably simpler than earlier work, and a 3D topological protocol for teleportation. PMID:28167790

3D abnormal behavior recognition in power generation

NASA Astrophysics Data System (ADS)

Wei, Zhenhua; Li, Xuesen; Su, Jie; Lin, Jie

2011-06-01

So far most research of human behavior recognition focus on simple individual behavior, such as wave, crouch, jump and bend. This paper will focus on abnormal behavior with objects carrying in power generation. Such as using mobile communication device in main control room, taking helmet off during working and lying down in high place. Taking account of the color and shape are fixed, we adopted edge detecting by color tracking to recognize object in worker. This paper introduces a method, which using geometric character of skeleton and its angle to express sequence of three-dimensional human behavior data. Then adopting Semi-join critical step Hidden Markov Model, weighing probability of critical steps' output to reduce the computational complexity. Training model for every behavior, mean while select some skeleton frames from 3D behavior sample to form a critical step set. This set is a bridge linking 2D observation behavior with 3D human joints feature. The 3D reconstruction is not required during the 2D behavior recognition phase. In the beginning of recognition progress, finding the best match for every frame of 2D observed sample in 3D skeleton set. After that, 2D observed skeleton frames sample will be identified as a specifically 3D behavior by behavior-classifier. The effectiveness of the proposed algorithm is demonstrated with experiments in similar power generation environment.

Evolution of the Thermal Conductivity of Sintered Silver Joints with their Porosity Predicted by the Finite Element Analysis of Real 3D Microstructures

NASA Astrophysics Data System (ADS)

Signor, L.; Kumar, P.; Tressou, B.; Nadot-Martin, C.; Miranda-Ordonez, José; Carr, J.; Joulain, K.; Milhet, X.

2018-07-01

Silver paste sintering is a very promising technology for chip bonding in future power electronics modules owing to its high melting temperature and the good electrical and thermal properties among other classic solder alloys. However, in its sintered form, these joints contain nanometric/submicrometric pores that affect their thermal performance. The present study gives insight into the relationship between the material thermal conductivity and the real three-dimensional porous structure using finite element modelling. It is shown that over a certain pore fraction threshold (˜ 13%), the pore morphology has a non-negligible influence on the thermal conductivity. Results are also compared to predictions obtained by analytical models available in the literature.

Evolution of the Thermal Conductivity of Sintered Silver Joints with their Porosity Predicted by the Finite Element Analysis of Real 3D Microstructures

NASA Astrophysics Data System (ADS)

Signor, L.; Kumar, P.; Tressou, B.; Nadot-Martin, C.; Miranda-Ordonez, José; Carr, J.; Joulain, K.; Milhet, X.

2018-03-01

Silver paste sintering is a very promising technology for chip bonding in future power electronics modules owing to its high melting temperature and the good electrical and thermal properties among other classic solder alloys. However, in its sintered form, these joints contain nanometric/submicrometric pores that affect their thermal performance. The present study gives insight into the relationship between the material thermal conductivity and the real three-dimensional porous structure using finite element modelling. It is shown that over a certain pore fraction threshold (˜ 13%), the pore morphology has a non-negligible influence on the thermal conductivity. Results are also compared to predictions obtained by analytical models available in the literature.

3D/2D image registration method for joint motion analysis using low-quality images from mini C-arm machines

NASA Astrophysics Data System (ADS)

Ghafurian, Soheil; Hacihaliloglu, Ilker; Metaxas, Dimitris N.; Tan, Virak; Li, Kang

2017-03-01

A 3D kinematic measurement of joint movement is crucial for orthopedic surgery assessment and diagnosis. This is usually obtained through a frame-by-frame registration of the 3D bone volume to a fluoroscopy video of the joint movement. The high cost of a high-quality fluoroscopy imaging system has hindered the access of many labs to this application. This is while the more affordable and low-dosage version, the mini C-arm, is not commonly used for this application due to low image quality. In this paper, we introduce a novel method for kinematic analysis of joint movement using the mini C-arm. In this method the bone of interest is recovered and isolated from the rest of the image using a non-rigid registration of an atlas to each frame. The 3D/2D registration is then performed using the weighted histogram of image gradients as an image feature. In our experiments, the registration error was 0.89 mm and 2.36° for human C2 vertebra. While the precision is still lacking behind a high quality fluoroscopy machine, it is a good starting point facilitating the use of mini C-arms for motion analysis making this application available to lower-budget environments. Moreover, the registration was highly resistant to the initial distance from the true registration, converging to the answer from anywhere within +/-90° of it.

A robust statistical estimation (RoSE) algorithm jointly recovers the 3D location and intensity of single molecules accurately and precisely

NASA Astrophysics Data System (ADS)

Mazidi, Hesam; Nehorai, Arye; Lew, Matthew D.

2018-02-01

In single-molecule (SM) super-resolution microscopy, the complexity of a biological structure, high molecular density, and a low signal-to-background ratio (SBR) may lead to imaging artifacts without a robust localization algorithm. Moreover, engineered point spread functions (PSFs) for 3D imaging pose difficulties due to their intricate features. We develop a Robust Statistical Estimation algorithm, called RoSE, that enables joint estimation of the 3D location and photon counts of SMs accurately and precisely using various PSFs under conditions of high molecular density and low SBR.

Simulation on the internal structure of three-dimensional proximal tibia under different mechanical environments.

PubMed

Fang, Juan; Gong, He; Kong, Lingyan; Zhu, Dong

2013-12-20

Bone can adjust its morphological structure to adapt to the changes of mechanical environment, i.e. the bone structure change is related to mechanical loading. This implies that osteoarthritis may be closely associated with knee joint deformity. The purposes of this paper were to simulate the internal bone mineral density (BMD) change in three-dimensional (3D) proximal tibia under different mechanical environments, as well as to explore the relationship between mechanical environment and bone morphological abnormity. The right proximal tibia was scanned with CT to reconstruct a 3D proximal tibia model in MIMICS, then it was imported to finite element software ANSYS to establish 3D finite element model. The internal structure of 3D proximal tibia of young normal people was simulated using quantitative bone remodeling theory in combination with finite element method, then based on the changing pattern of joint contact force on the tibial plateau in valgus knees, the mechanical loading was changed, and the simulated normal tibia structure was used as initial structure to simulate the internal structure of 3D proximal tibia for old people with 6° valgus deformity. Four regions of interest (ROIs) were selected in the proximal tibia to quantitatively analyze BMD and compare with the clinical measurements. The simulation results showed that the BMD distribution in 3D proximal tibia was consistent with clinical measurements in normal knees and that in valgus knees was consistent with the measurement of patients with osteoarthritis in clinics. It is shown that the change of mechanical environment is the main cause for the change of subchondral bone structure, and being under abnormal mechanical environment for a long time may lead to osteoarthritis. Besides, the simulation method adopted in this paper can more accurately simulate the internal structure of 3D proximal tibia under different mechanical environments. It helps to better understand the mechanism of osteoarthritis and provides theoretical basis and computational method for the prevention and treatment of osteoarthritis. It can also serve as basis for further study on periprosthetic BMD changes after total knee arthroplasty, and provide a theoretical basis for optimization design of prosthesis.

Simulation on the internal structure of three-dimensional proximal tibia under different mechanical environments

PubMed Central

2013-01-01

Background Bone can adjust its morphological structure to adapt to the changes of mechanical environment, i.e. the bone structure change is related to mechanical loading. This implies that osteoarthritis may be closely associated with knee joint deformity. The purposes of this paper were to simulate the internal bone mineral density (BMD) change in three-dimensional (3D) proximal tibia under different mechanical environments, as well as to explore the relationship between mechanical environment and bone morphological abnormity. Methods The right proximal tibia was scanned with CT to reconstruct a 3D proximal tibia model in MIMICS, then it was imported to finite element software ANSYS to establish 3D finite element model. The internal structure of 3D proximal tibia of young normal people was simulated using quantitative bone remodeling theory in combination with finite element method, then based on the changing pattern of joint contact force on the tibial plateau in valgus knees, the mechanical loading was changed, and the simulated normal tibia structure was used as initial structure to simulate the internal structure of 3D proximal tibia for old people with 6° valgus deformity. Four regions of interest (ROIs) were selected in the proximal tibia to quantitatively analyze BMD and compare with the clinical measurements. Results The simulation results showed that the BMD distribution in 3D proximal tibia was consistent with clinical measurements in normal knees and that in valgus knees was consistent with the measurement of patients with osteoarthritis in clinics. Conclusions It is shown that the change of mechanical environment is the main cause for the change of subchondral bone structure, and being under abnormal mechanical environment for a long time may lead to osteoarthritis. Besides, the simulation method adopted in this paper can more accurately simulate the internal structure of 3D proximal tibia under different mechanical environments. It helps to better understand the mechanism of osteoarthritis and provides theoretical basis and computational method for the prevention and treatment of osteoarthritis. It can also serve as basis for further study on periprosthetic BMD changes after total knee arthroplasty, and provide a theoretical basis for optimization design of prosthesis. PMID:24359345

No evidence for the use of DIR, D–D fusions, chromosome 15 open reading frames or VHreplacement in the peripheral repertoire was found on application of an improved algorithm, JointML, to 6329 human immunoglobulin H rearrangements

PubMed Central

Ohm-Laursen, Line; Nielsen, Morten; Larsen, Stine R; Barington, Torben

2006-01-01

Antibody diversity is created by imprecise joining of the variability (V), diversity (D) and joining (J) gene segments of the heavy and light chain loci. Analysis of rearrangements is complicated by somatic hypermutations and uncertainty concerning the sources of gene segments and the precise way in which they recombine. It has been suggested that D genes with irregular recombination signal sequences (DIR) and chromosome 15 open reading frames (OR15) can replace conventional D genes, that two D genes or inverted D genes may be used and that the repertoire can be further diversified by heavy chain V gene (VH) replacement. Safe conclusions require large, well-defined sequence samples and algorithms minimizing stochastic assignment of segments. Two computer programs were developed for analysis of heavy chain joints. JointHMM is a profile hidden Markow model, while JointML is a maximum-likelihood-based method taking the lengths of the joint and the mutational status of the VH gene into account. The programs were applied to a set of 6329 clonally unrelated rearrangements. A conventional D gene was found in 80% of unmutated sequences and 64% of mutated sequences, while D-gene assignment was kept below 5% in artificial (randomly permutated) rearrangements. No evidence for the use of DIR, OR15, multiple D genes or VH replacements was found, while inverted D genes were used in less than 1‰ of the sequences. JointML was shown to have a higher predictive performance for D-gene assignment in mutated and unmutated sequences than four other publicly available programs. An online version 1·0 of JointML is available at http://www.cbs.dtu.dk/services/VDJsolver. PMID:17005006

Recent Advances in Tissue Engineering Strategies for the Treatment of Joint Damage.

PubMed

Stephenson, Makeda K; Farris, Ashley L; Grayson, Warren L

2017-08-01

While the clinical potential of tissue engineering for treating joint damage has yet to be realized, research and commercialization efforts in the field are geared towards overcoming major obstacles to clinical translation, as well as towards achieving engineered grafts that recapitulate the unique structures, function, and physiology of the joint. In this review, we describe recent advances in technologies aimed at obtaining biomaterials, stem cells, and bioreactors that will enable the development of effective tissue-engineered treatments for repairing joint damage. 3D printing of scaffolds is aimed at improving the mechanical structure and microenvironment necessary for bone regeneration within a damaged joint. Advances in our understanding of stem cell biology and cell manufacturing processes are informing translational strategies for the therapeutic use of allogeneic and autologous cells. Finally, bioreactors used in combination with cells and biomaterials are promising strategies for generating large tissue grafts for repairing damaged tissues in pre-clinical models. Together, these advances along with ongoing research directions are making tissue engineering increasingly viable for the treatment of joint damage.

IDEAL 3D spoiled gradient echo of the articular cartilage of the knee on 3.0 T MRI: a comparison with conventional 3.0 T fast spin-echo T2 fat saturation image.

PubMed

Han, Chul Hee; Park, Hee Jin; Lee, So Yeon; Chung, Eun Chul; Choi, Seon Hyeong; Yun, Ji Sup; Rho, Myung Ho

2015-12-01

Many two-dimensional (2D) morphologic cartilage imaging sequences have disadvantages such as long acquisition time, inadequate spatial resolution, suboptimal tissue contrast, and image degradation secondary to artifacts. IDEAL imaging can overcome these disadvantages. To compare sound-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and quality of two different methods of imaging that include IDEAL 3D SPGR and 3.0-T FSE T2 fat saturation (FS) imaging and to evaluate the utility of IDEAL 3D SPGR for knee joint imaging. SNR and CNR of the patellar and femoral cartilages were measured and calculated. Two radiologists performed subjective scoring of all images for three measures: general image quality, FS, and cartilage evaluation. SNR and CNR values were compared by paired Student's t-tests. Mean SNRs of patellar and femoral cartilages were 90% and 66% higher, respectively, for IDEAL 3D SPGR. CNRs of patellar cartilages and joint fluids were 2.4 times higher for FSE T2 FS, and CNR between the femoral cartilage and joint fluid was 2.2 times higher for FSE T2 FS. General image quality and FS were superior using FSE T2 FS compared to those of IDEAL 3D SPGR imaging according to both readers, while cartilage evaluation was superior using IDEAL 3D SPGR. Additionally, cartilage injuries were more prominent in IDEAL 3D SPGR than in FSE T2FS according to both readers. IDEAL 3D SPGR images show excellent visualization of patellar and femoral cartilages in 3.0 T and can compensate for the weaknesses of FSE T2 FS in the evaluation of cartilage injuries. © The Foundation Acta Radiologica 2014.

Prediction of In Vivo Knee Joint Kinematics Using a Combined Dual Fluoroscopy Imaging and Statistical Shape Modeling Technique

PubMed Central

Li, Jing-Sheng; Tsai, Tsung-Yuan; Wang, Shaobai; Li, Pingyue; Kwon, Young-Min; Freiberg, Andrew; Rubash, Harry E.; Li, Guoan

2014-01-01

Using computed tomography (CT) or magnetic resonance (MR) images to construct 3D knee models has been widely used in biomedical engineering research. Statistical shape modeling (SSM) method is an alternative way to provide a fast, cost-efficient, and subject-specific knee modeling technique. This study was aimed to evaluate the feasibility of using a combined dual-fluoroscopic imaging system (DFIS) and SSM method to investigate in vivo knee kinematics. Three subjects were studied during a treadmill walking. The data were compared with the kinematics obtained using a CT-based modeling technique. Geometric root-mean-square (RMS) errors between the knee models constructed using the SSM and CT-based modeling techniques were 1.16 mm and 1.40 mm for the femur and tibia, respectively. For the kinematics of the knee during the treadmill gait, the SSM model can predict the knee kinematics with RMS errors within 3.3 deg for rotation and within 2.4 mm for translation throughout the stance phase of the gait cycle compared with those obtained using the CT-based knee models. The data indicated that the combined DFIS and SSM technique could be used for quick evaluation of knee joint kinematics. PMID:25320846

Joint Simultaneous Reconstruction of Regularized Building Superstructures from Low-Density LIDAR Data Using Icp

NASA Astrophysics Data System (ADS)

Wichmann, Andreas; Kada, Martin

2016-06-01

There are many applications for 3D city models, e.g., in visualizations, analysis, and simulations; each one requiring a certain level of detail to be effective. The overall trend goes towards including various kinds of anthropogenic and natural objects therein with ever increasing geometric and semantic details. A few years back, the featured 3D building models had only coarse roof geometry. But nowadays, they are expected to include detailed roof superstructures like dormers and chimneys. Several methods have been proposed for the automatic reconstruction of 3D building models from airborne based point clouds. However, they are usually unable to reliably recognize and reconstruct small roof superstructures as these objects are often represented by only few point measurements, especially in low-density point clouds. In this paper, we propose a recognition and reconstruction approach that overcomes this problem by identifying and simultaneously reconstructing regularized superstructures of similar shape. For this purpose, candidate areas for superstructures are detected by taking into account virtual sub-surface points that are assumed to lie on the main roof faces below the measured points. The areas with similar superstructures are detected, extracted, grouped together, and registered to one another with the Iterative Closest Point (ICP) algorithm. As an outcome, the joint point density of each detected group is increased, which helps to recognize the shape of the superstructure more reliably and in more detail. Finally, all instances of each group of superstructures are modeled at once and transformed back to their original position. Because superstructures are reconstructed in groups, symmetries, alignments, and regularities can be enforced in a straight-forward way. The validity of the approach is presented on a number of example buildings from the Vaihingen test data set.

Three-Dimensional Slowness Images of the Upper Crust Beneath the Lucky Strike Hydrothermal Vent Sites

NASA Astrophysics Data System (ADS)

Seher, T.; Crawford, W.; Singh, S.; Canales, J. P.; Combier, V.; Cannat, M.; Carton, H.; Dusunur, D.; Escartin, J.; Miranda, M. J.; Pouillet-Erguy, A.

2005-12-01

In June-July 2005 we carried out the SISMOMAR cruise, as part of the MOMAR project (Monitoring the Mid-Atlantic Ridge). Within this cruise, we conducted a 3D seismic reflection survey over an 18 km km x 3.8 km area covering both the Lucky Strike volcano and hydrothermal vents field. In order to have a full coverage inside the 3D box, shots continued for 2.25 km on either side of the box and extended out to the median valley bounding faults. To complement the streamer measurements 25 Ocean Bottom Seismometers (OBS) were placed in an 18 km x 18 km area. 11 OBS positions lie inside the 3D box and can be used to determine a very detailed image of the 3D velocity structure beneath the Lucky Strike volcano and hydrothermal vents field. For the 3D box a tuned array of 14 air guns (2600 cubic inches) was fired at an interval of 37.5 m for a total of 39 lines. We will present the first results of the OBS measurements near the Lucky Strike volcano. As a first step towards a joint 3D travel time and slowness (the inverse of velocity at turning depth) tomography, we present the 3D slowness function (latitude, longitude, offset), which can be considered as a 3D brute stack velocity image of the sub-surface (c.f. Barton and Edwards, 1999). The presence of fluid in the upper crust due to hydrothermal circulation should appear as a low velocity anomaly beneath the hydrothermal vents. In the next step the OBS measurements will be used to corroborate the reflection images of layer 2A observed in the streamer data for the 3D box. The OBS inside the 3D box recorded turning ray arrivals from the upper crust at a very fine sampling interval (37.5 m x 100 m) over a large azimuth. This provides the unique opportunity for jointly inverting travel time and slowness. Hence the measurements contain information on local gradients and should provide a very detailed velocity model of the subsurface, including information on hydrothermal systems and a possilbe anisotropy (e.g. Cherret and Singh, 1999). References: P. Barton, R. Edwards: Velocity imaging by tau-p transformation, LITHOS Science Report, 1999, 1, 67-75. A. Cherrett, S. Singh: 3D anisotropic models from multi-component data, LITHOS Science Report, 1999, 1, 29-34.

Development of Intra-knee Joint Sustained-Release Gel Formulation and Evaluation of Its Pharmacological Efficiency in Rats.

PubMed

Noda, Takehiro; Okuda, Tomoyuki; Ban, Kousuke; Mizuno, Ryota; Tagami, Tatsuaki; Ozeki, Tetsuya; Okamoto, Hirokazu

2017-06-01

In the development of a drug for intra-articular administration, a sustained-release formulation is desirable since it is difficult to sustain the effects of conventional injections due to fast drug leakage from the joint cavity. In this study, we prepared sustained release gel formulations for intra-articular administration containing indocyanine green (ICG) as a model drug to follow its fate after intra-articular administration in rats with in-vivo imaging system (IVIS). ICG administered as an aqueous solution leaked from the joint cavity in a short time and was excreted out of the body within a day. On the other hand, ICG in the sustained-release formulations was retained and released in the joint cavity for a week. Next, we prepared a sustained-release formulation with hyaluronic acid (HA) as the gel base containing a pain-relief drug (Drug A). We had administered it and other formulations into the rat knee where we injected bradykinin to evaluate their walking distance after 1 and 3 d. The effect of an aqueous solution of Drug A disappeared on day 3. The HA gel formulation without Drug A was more effective than the aqueous solution. The HA gel formulation with Drug A was the most effective; the walking distance was about 85% of the baseline on day 3. This study showed that the gel formulations were effective to sustain the release of a drug in the knee joint, and that the combination of a pain-relief drug with HA gel was effective to improve the mobility of the acute pain model rats.

3D joint inversion modeling of the lithospheric density structure based on gravity, geoid and topography data — Application to the Alborz Mountains (Iran) and South Caspian Basin region

NASA Astrophysics Data System (ADS)

Motavalli-Anbaran, Seyed-Hani; Zeyen, Hermann; Ebrahimzadeh Ardestani, Vahid

2013-02-01

We present a 3D algorithm to obtain the density structure of the lithosphere from joint inversion of free air gravity, geoid and topography data based on a Bayesian approach with Gaussian probability density functions. The algorithm delivers the crustal and lithospheric thicknesses and the average crustal density. Stabilization of the inversion process may be obtained through parameter damping and smoothing as well as use of a priori information like crustal thicknesses from seismic profiles. The algorithm is applied to synthetic models in order to demonstrate its usefulness. A real data application is presented for the area of northern Iran (with the Alborz Mountains as main target) and the South Caspian Basin. The resulting model shows an important crustal root (up to 55 km) under the Alborz Mountains and a thin crust (ca. 30 km) under the southernmost South Caspian Basin thickening northward to the Apsheron-Balkan Sill to 45 km. Central and NW Iran is underlain by a thin lithosphere (ca. 90-100 km). The lithosphere thickens under the South Caspian Basin until the Apsheron-Balkan Sill where it reaches more than 240 km. Under the stable Turan platform, we find a lithospheric thickness of 160-180 km.

Gender Dimorphic ACL Strain In Response to Combined Dynamic 3D Knee Joint Loading: Implications for ACL Injury Risk

PubMed Central

Mizuno, Kiyonori; Andrish, Jack T.; van den Bogert, Antonie J.; McLean, Scott G.

2009-01-01

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (~10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as a function of the combined 6 DOF knee loads. Following individual model verifications, generalized gender-specific models were generated and subjected to 6 DOF external load scenarios consistent with both a clinical examination and a dynamic sports maneuver. The ensuing model-based strain predictions were subsequently examined for gender-based discrepancies. Male and female specimen specific models predicted ACL strain within 0.51% ± 0.10% and 0.52% ± 0.07% of the measured data respectively, and explained more than 75% of the associated variance in each case. Predicted female ACL strains were also significantly larger than respective male values for both of simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities. PMID:19464897

Improvements of Travel-time Tomography Models from Joint Inversion of Multi-channel and Wide-angle Seismic Data

NASA Astrophysics Data System (ADS)

Begović, Slaven; Ranero, César; Sallarès, Valentí; Meléndez, Adrià; Grevemeyer, Ingo

2016-04-01

Commonly multichannel seismic reflection (MCS) and wide-angle seismic (WAS) data are modeled and interpreted with different approaches. Conventional travel-time tomography models using solely WAS data lack the resolution to define the model properties and, particularly, the geometry of geologic boundaries (reflectors) with the required accuracy, specially in the shallow complex upper geological layers. We plan to mitigate this issue by combining these two different data sets, specifically taking advantage of the high redundancy of multichannel seismic (MCS) data, integrated with wide-angle seismic (WAS) data into a common inversion scheme to obtain higher-resolution velocity models (Vp), decrease Vp uncertainty and improve the geometry of reflectors. To do so, we have adapted the tomo2d and tomo3d joint refraction and reflection travel time tomography codes (Korenaga et al, 2000; Meléndez et al, 2015) to deal with streamer data and MCS acquisition geometries. The scheme results in a joint travel-time tomographic inversion based on integrated travel-time information from refracted and reflected phases from WAS data and reflected identified in the MCS common depth point (CDP) or shot gathers. To illustrate the advantages of a common inversion approach we have compared the modeling results for synthetic data sets using two different travel-time inversion strategies: We have produced seismic velocity models and reflector geometries following typical refraction and reflection travel-time tomographic strategy modeling just WAS data with a typical acquisition geometry (one OBS each 10 km). Second, we performed joint inversion of two types of seismic data sets, integrating two coincident data sets consisting of MCS data collected with a 8 km-long streamer and the WAS data into a common inversion scheme. Our synthetic results of the joint inversion indicate a 5-10 times smaller ray travel-time misfit in the deeper parts of the model, compared to models obtained using just wide-angle seismic data. As expected, there is an important improvement in the definition of the reflector geometry, which in turn, allows to improve the accuracy of the velocity retrieval just above and below the reflector. To test the joint inversion approach with real data, we combined wide-angle (WAS) seismic and coincident multichannel seismic reflection (MCS) data acquired in the northern Chile subduction zone into a common inversion scheme to obtain a higher-resolution information of upper plate and inter-plate boundary.

A Practical Strategy for sEMG-Based Knee Joint Moment Estimation During Gait and Its Validation in Individuals With Cerebral Palsy

PubMed Central

Kwon, Suncheol; Stanley, Christopher J.; Kim, Jung; Kim, Jonghyun; Damiano, Diane L.

2013-01-01

Individuals with cerebral palsy have neurological deficits that may interfere with motor function and lead to abnormal walking patterns. It is important to know the joint moment generated by the patient’s muscles during walking in order to assist the suboptimal gait patterns. In this paper, we describe a practical strategy for estimating the internal moment of a knee joint from surface electromyography (sEMG) and knee joint angle measurements. This strategy requires only isokinetic knee flexion and extension tests to obtain a relationship between the sEMG and the knee internal moment, and it does not necessitate comprehensive laboratory calibration, which typically requires a 3-D motion capture system and ground reaction force plates. Four estimation models were considered based on different assumptions about the functions of the relevant muscles during the isokinetic tests and the stance phase of walking. The performance of the four models was evaluated by comparing the estimated moments with the gold standard internal moment calculated from inverse dynamics. The results indicate that an optimal estimation model can be chosen based on the degree of cocontraction. The estimation error of the chosen model is acceptable (normalized root-mean-squared error: 0.15–0.29, R: 0.71–0.93) compared to previous studies (Doorenbosch and Harlaar, 2003; Doorenbosch and Harlaar, 2004; Doorenbosch, Joosten, and Harlaar, 2005), and this strategy provides a simple and effective solution for estimating knee joint moment from sEMG. PMID:22410952

Choosing sheep (Ovis aries) as animal model for temporomandibular joint research: Morphological, histological and biomechanical characterization of the joint disc.

PubMed

Angelo, D F; Morouço, P; Alves, N; Viana, T; Santos, F; González, R; Monje, F; Macias, D; Carrapiço, B; Sousa, R; Cavaco-Gonçalves, S; Salvado, F; Peleteiro, C; Pinho, M

2016-12-01

Preclinical trials are essential to the development of scientific technologies. Remarkable molecular and cellular research has been done using small animal models. However, significant differences exist regarding the articular behavior between these models and humans. Thus, large animal models may be more appropriate to perform trials involving the temporomandibular joint (TMJ). The aim of this work was to make a morphological (anatomic dissection and white light 3D scanning system), histological (TMJ in bloc was removed for histologic analysis) and biomechanical characterization (tension and compression tests) of sheep TMJ comparing the obtained results with human data. Results showed that sheep processus condylaris and fossa mandibularis are anatomically similar to the same human structures. TMJ disc has an elliptical perimeter, thinner in the center than in periphery. Peripheral area acts as a ring structure supporting the central zone. The disc cells display both fibroblast and chondrocyte-like morphology. Marginal area is formed by loose connective tissue, with some chondrocyte-like cells and collagen fibers in diverse orientations. Discs obtained a tensile modulus of 3.97±0.73MPa and 9.39±1.67MPa, for anteroposterior and mediolateral assessment. The TMJ discs presented a compressive modulus (E) of 446.41±5.16MPa and their maximum stress value (σmax) was 18.87±1.33MPa. Obtained results suggest that these animals should be considered as a prime model for TMJ research and procedural training. Further investigations in the field of oromaxillofacial surgery involving TMJ should consider sheep as a good animal model due to its resemblance of the same joint in humans. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Efficient segmentation of 3D fluoroscopic datasets from mobile C-arm

NASA Astrophysics Data System (ADS)

Styner, Martin A.; Talib, Haydar; Singh, Digvijay; Nolte, Lutz-Peter

2004-05-01

The emerging mobile fluoroscopic 3D technology linked with a navigation system combines the advantages of CT-based and C-arm-based navigation. The intra-operative, automatic segmentation of 3D fluoroscopy datasets enables the combined visualization of surgical instruments and anatomical structures for enhanced planning, surgical eye-navigation and landmark digitization. We performed a thorough evaluation of several segmentation algorithms using a large set of data from different anatomical regions and man-made phantom objects. The analyzed segmentation methods include automatic thresholding, morphological operations, an adapted region growing method and an implicit 3D geodesic snake method. In regard to computational efficiency, all methods performed within acceptable limits on a standard Desktop PC (30sec-5min). In general, the best results were obtained with datasets from long bones, followed by extremities. The segmentations of spine, pelvis and shoulder datasets were generally of poorer quality. As expected, the threshold-based methods produced the worst results. The combined thresholding and morphological operations methods were considered appropriate for a smaller set of clean images. The region growing method performed generally much better in regard to computational efficiency and segmentation correctness, especially for datasets of joints, and lumbar and cervical spine regions. The less efficient implicit snake method was able to additionally remove wrongly segmented skin tissue regions. This study presents a step towards efficient intra-operative segmentation of 3D fluoroscopy datasets, but there is room for improvement. Next, we plan to study model-based approaches for datasets from the knee and hip joint region, which would be thenceforth applied to all anatomical regions in our continuing development of an ideal segmentation procedure for 3D fluoroscopic images.

[Principles of the EOS™ X-ray machine and its use in daily orthopedic practice].

PubMed

Illés, Tamás; Somoskeöy, Szabolcs

2012-02-26

The EOS™ X-ray machine, based on a Nobel prize-winning invention in Physics in the field of particle detection, is capable of simultaneously capturing biplanar X-ray images by slot scanning of the whole body in an upright, physiological load-bearing position, using ultra low radiation doses. The simultaneous capture of spatially calibrated anterioposterior and lateral images allows the performance of a three-dimensional (3D) surface reconstruction of the skeletal system by a special software. Parts of the skeletal system in X-ray images and 3D-reconstructed models appear in true 1:1 scale for size and volume, thus spinal and vertebral parameters, lower limb axis lengths and angles, as well as any relevant clinical parameters in orthopedic practice could be very precisely measured and calculated. Visualization of 3D reconstructed models in various views by the sterEOS 3D software enables the presentation of top view images, through which one can analyze the rotational conditions of lower limbs, joints and spine deformities in horizontal plane and this provides revolutionary novel possibilities in orthopedic surgery, especially in spine surgery.

Impact of 3-D seismic data on the Nigerian National Petroleum Corporation/Chevron Nigeria Limited joint venture development drilling program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quam, S.

The Nigerian National Petroleum Corporation/Chevron Nigeria Limited joint venture has been acquiring three-dimensional (3-D) seismic data over its concessions since 1984. To date, 1700 km[sup 2] have been recorded and processed at a cumulative cost of US $39 million. During 1991 - 1992, 20 development wells were drilled based directly on new 3-D seismic interpretations. These wells have added 148 million bbl of oil in new recoverable reserves, and to date have added 37,000 bbl/day to the joint venture's production. In addition, the 3-D interpretations have resulted in a sizable inventory of wells for future development drilling. The new 3-Dmore » interpretations provided more accurate pictures of fault patterns, fluid contacts, channel trends, stratigraphic continuity, and velocity/amplitude anomalies. In addition, the 3-D data were invaluable in designing low risk, directional well trajectories to tap relatively thin oil legs under large gas caps. Wells often were programmed to hit several objectives at their respective gas/oil contacts, resulting in maximized net oil sand pays and reducing the risk of gas production. In order to do this, directional [open quotes]sharpshooting,[close quotes] accurate depth conversion of the seismic time maps, was critical. By using the 3-D seismic, checkshot, and sonic data to develop a variable velocity space, well-top prognoses within 50 ft at depths of 6,000-10,000 ft were possible, and were key to the success of the program. As the joint venture acreage becomes more mature, development wells will be drilled for smaller numbers of stacked objectives, and sometimes for single sands. Highly accurate 3-D interpretations and depth conversions will become even more critical in order to tap thinner pay zones in a cost-effect manner.« less

Retrieving Precise Three-Dimensional Deformation on the 2014 M6.0 South Napa Earthquake by Joint Inversion of Multi-Sensor SAR.

PubMed

Jo, Min-Jeong; Jung, Hyung-Sup; Yun, Sang-Ho

2017-07-14

We reconstructed the three-dimensional (3D) surface displacement field of the 24 August 2014 M6.0 South Napa earthquake using SAR data from the Italian Space Agency's COSMO-SkyMed and the European Space Agency's Sentinel-1A satellites. Along-track and cross-track displacements produced with conventional SAR interferometry (InSAR) and multiple-aperture SAR interferometry (MAI) techniques were integrated to retrieve the east, north, and up components of surface deformation. The resulting 3D displacement maps clearly delineated the right-lateral shear motion of the fault rupture with a maximum surface displacement of approximately 45 cm along the fault's strike, showing the east and north components of the trace particularly clearly. These maps also suggested a better-constrained model for the South Napa earthquake. We determined a strike of approximately 338° and dip of 85° by applying the Okada dislocation model considering a single patch with a homogeneous slip motion. Using the distributed slip model obtained by a linear solution, we estimated that a peak slip of approximately 1.7 m occurred around 4 km depth from the surface. 3D modelling using the retrieved 3D maps helps clarify the fault's nature and thus characterize its behaviour.

Solid images generated from UAVs to analyze areas affected by rock falls

NASA Astrophysics Data System (ADS)

Giordan, Daniele; Manconi, Andrea; Allasia, Paolo; Baldo, Marco

2015-04-01

The study of rock fall affected areas is usually based on the recognition of principal joints families and the localization of potential instable sectors. This requires the acquisition of field data, although as the areas are barely accessible and field inspections are often very dangerous. For this reason, remote sensing systems can be considered as suitable alternative. Recently, Unmanned Aerial Vehicles (UAVs) have been proposed as platform to acquire the necessary information. Indeed, mini UAVs (in particular in the multi-rotors configuration) provide versatility for the acquisition from different points of view a large number of high resolution optical images, which can be used to generate high resolution digital models relevant to the study area. By considering the recent development of powerful user-friendly software and algorithms to process images acquired from UAVs, there is now a need to establish robust methodologies and best-practice guidelines for correct use of 3D models generated in the context of rock fall scenarios. In this work, we show how multi-rotor UAVs can be used to survey areas by rock fall during real emergency contexts. We present two examples of application located in northwestern Italy: the San Germano rock fall (Piemonte region) and the Moneglia rock fall (Liguria region). We acquired data from both terrestrial LiDAR and UAV, in order to compare digital elevation models generated with different remote sensing approaches. We evaluate the volume of the rock falls, identify the areas potentially unstable, and recognize the main joints families. The use on is not so developed but probably this approach can be considered the better solution for a structural investigation of large rock walls. We propose a methodology that jointly considers the Structure from Motion (SfM) approach for the generation of 3D solid images, and a geotechnical analysis for the identification of joint families and potential failure planes.

Voxel inversion of airborne electromagnetic data

NASA Astrophysics Data System (ADS)

Auken, E.; Fiandaca, G.; Kirkegaard, C.; Vest Christiansen, A.

2013-12-01

Inversion of electromagnetic data usually refers to a model space being linked to the actual observation points, and for airborne surveys the spatial discretization of the model space reflects the flight lines. On the contrary, geological and groundwater models most often refer to a regular voxel grid, not correlated to the geophysical model space. This means that incorporating the geophysical data into the geological and/or hydrological modelling grids involves a spatial relocation of the models, which in itself is a subtle process where valuable information is easily lost. Also the integration of prior information, e.g. from boreholes, is difficult when the observation points do not coincide with the position of the prior information, as well as the joint inversion of airborne and ground-based surveys. We developed a geophysical inversion algorithm working directly in a voxel grid disconnected from the actual measuring points, which then allows for informing directly geological/hydrogeological models, for easier incorporation of prior information and for straightforward integration of different data types in joint inversion. The new voxel model space defines the soil properties (like resistivity) on a set of nodes, and the distribution of the properties is computed everywhere by means of an interpolation function f (e.g. inverse distance or kriging). The position of the nodes is fixed during the inversion and is chosen to sample the soil taking into account topography and inversion resolution. Given this definition of the voxel model space, both 1D and 2D/3D forward responses can be computed. The 1D forward responses are computed as follows: A) a 1D model subdivision, in terms of model thicknesses and direction of the "virtual" horizontal stratification, is defined for each 1D data set. For EM soundings the "virtual" horizontal stratification is set up parallel to the topography at the sounding position. B) the "virtual" 1D models are constructed by interpolating the soil properties in the medium point of the "virtual" layers. For 2D/3D forward responses the algorithm operates similarly, simply filling the 2D/3D meshes of the forward responses by computing the interpolation values in the centres of the mesh cells. The new definition of the voxel model space allows for incorporating straightforwardly the geophysical information into geological and/or hydrological models, just by using for defining the geophysical model space a voxel (hydro)geological grid. This simplify also the propagation of the uncertainty of geophysical parameters into the (hydro)geological models. Furthermore, prior information from boreholes, like resistivity logs, can be applied directly to the voxel model space, even if the borehole positions do not coincide with the actual observation points. In fact, the prior information is constrained to the model parameters through the interpolation function at the borehole locations. The presented algorithm is a further development of the AarhusInv program package developed at Aarhus University (formerly em1dinv), which manages both large scale AEM surveys and ground-based data. This work has been carried out as part of the HyGEM project, supported by the Danish Council of Strategic Research under grant number DSF 11-116763.

Three Dimensional Characterization of Tin Crystallography and Cu6Sn5 Intermetallics in Solder Joints by Multiscale Tomography

NASA Astrophysics Data System (ADS)

Kirubanandham, A.; Lujan-Regalado, I.; Vallabhaneni, R.; Chawla, N.

2016-11-01

Decreasing pitch size in electronic packaging has resulted in a drastic decrease in solder volumes. The Sn grain crystallography and fraction of intermetallic compounds (IMCs) in small-scale solder joints evolve much differently at the smaller length scales. A cross-sectional study limits the morphological analysis of microstructural features to two dimensions. This study utilizes serial sectioning technique in conjunction with electron backscatter diffraction to investigate the crystallographic orientation of both Sn grains and Cu6Sn5 IMCs in Cu/Pure Sn/Cu solder joints in three dimensional (3D). Quantification of grain aspect ratio is affected by local cooling rate differences within the solder volume. Backscatter electron imaging and focused ion beam serial sectioning enabled the visualization of morphology of both nanosized Cu6Sn5 IMCs and the hollow hexagonal morphology type Cu6Sn5 IMCs in 3D. Quantification and visualization of microstructural features in 3D thus enable us to better understand the microstructure and deformation mechanics within these small scale solder joints.

Fast Grasp Contact Computation for a Serial Robot

NASA Technical Reports Server (NTRS)

Hargrave, Brian (Inventor); Shi, Jianying (Inventor); Diftler, Myron A. (Inventor)

2015-01-01

A system includes a controller and a serial robot having links that are interconnected by a joint, wherein the robot can grasp a three-dimensional (3D) object in response to a commanded grasp pose. The controller receives input information, including the commanded grasp pose, a first set of information describing the kinematics of the robot, and a second set of information describing the position of the object to be grasped. The controller also calculates, in a two-dimensional (2D) plane, a set of contact points between the serial robot and a surface of the 3D object needed for the serial robot to achieve the commanded grasp pose. A required joint angle is then calculated in the 2D plane between the pair of links using the set of contact points. A control action is then executed with respect to the motion of the serial robot using the required joint angle.

Triangulation Based 3D Laser Imaging for Fracture Orientation Analysis

NASA Astrophysics Data System (ADS)

Mah, J.; Claire, S.; Steve, M.

2009-05-01

Laser imaging has recently been identified as a potential tool for rock mass characterization. This contribution focuses on the application of triangulation based, short-range laser imaging to determine fracture orientation and surface texture. This technology measures the distance to the target by triangulating the projected and reflected laser beams, and also records the reflection intensity. In this study, we acquired 3D laser images of rock faces using the Laser Camera System (LCS), a portable instrument developed by Neptec Design Group (Ottawa, Canada). The LCS uses an infrared laser beam and is immune to the lighting conditions. The maximum image resolution is 1024 x 1024 volumetric image elements. Depth resolution is 0.5 mm at 5 m. An above ground field trial was conducted at a blocky road cut with well defined joint sets (Kingston, Ontario). An underground field trial was conducted at the Inco 175 Ore body (Sudbury, Ontario) where images were acquired in the dark and the joint set features were more subtle. At each site, from a distance of 3 m away from the rock face, a grid of six images (approximately 1.6 m by 1.6 m) was acquired at maximum resolution with 20% overlap between adjacent images. This corresponds to a density of 40 image elements per square centimeter. Polyworks, a high density 3D visualization software tool, was used to align and merge the images into a single digital triangular mesh. The conventional method of determining fracture orientations is by manual measurement using a compass. In order to be accepted as a substitute for this method, the LCS should be capable of performing at least to the capabilities of manual measurements. To compare fracture orientation estimates derived from the 3D laser images to manual measurements, 160 inclinometer readings were taken at the above ground site. Three prominent joint sets (strike/dip: 236/09, 321/89, 325/01) were identified by plotting the joint poles on a stereonet. Underground, two main joint sets (strike/dip: 060/00, 114/86) were identified from 49 manual inclinometer measurements A stereonet of joint poles from the 3D laser data was generated using the commercial software Split-FX. Joint sets were identified successfully and their orientations correlated well with the hand measurements. However, Split-Fx overlays a simply 2D grid of equal-sized triangles onto the 3D surface and requires significant user input. In a more automated approach, we have developed a MATLAB script which directly imports the Polyworks 3D triangular mesh. A typical mesh is composed of over 1 million triangles of variable sizes: smooth regions are represented by large triangles, whereas rough surfaces are captured by several smaller triangles. Using the triangle vertices, the script computes the strike and dip of each triangle. This approach opens possibilities for statistical analysis of a large population of fracture orientation estimates, including surface texture. The methodology will be used to evaluate both synthetic and field data.

Lamb Wave Propagation in a Restricted Geometry Composite PI-Joint Specimen (Preprint)

DTIC Science & Technology

2011-11-01

adhesive, and were located along the length and height of the specimen as depicted in Figure 3. The sensors were 6.35 mm round disks of PZT , with a...in both cases for R1, R2, and R3. 3D Finite Element Model Geometry 200mm length 50mm width 140mm height x z y PZT Actuation Sensor...health monitoring using scanning laser vibrometry: III. Lamb waves for fatigue crack detection”, Smart Mater. Struct., Vol. 14, No. 6, 2005. 16

DOTAM derivatives as active cartilage-targeting drug carriers for the treatment of osteoarthritis.

PubMed

Hu, Hai-Yu; Lim, Ngee-Han; Ding-Pfennigdorff, Danping; Saas, Joachim; Wendt, K Ulrich; Ritzeler, Olaf; Nagase, Hideaki; Plettenburg, Oliver; Schultz, Carsten; Nazare, Marc

2015-03-18

Targeted drug-delivery methods are crucial for effective treatment of degenerative joint diseases such as osteoarthritis (OA). Toward this goal, we developed a small multivalent structure as a model drug for the attenuation of cartilage degradation. The DOTAM (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid amide)-based model structure is equipped with the cathepsin D protease inhibitor pepstatin A, a fluorophore, and peptide moieties targeting collagen II. In vivo injection of these soluble probes into the knee joints of mice resulted in 7-day-long local retention, while the drug carrier equipped with a scrambled peptide sequence was washed away within 6-8 h. The model drug conjugate successfully reduced the cathepsin D protease activity as measured by release of GAG peptide. Therefore, these conjugates represent a promising first drug conjugate for the targeted treatment of degenerative joint diseases.

Comparison of 3D dynamic virtual model to link segment model for estimation of net L4/L5 reaction moments during lifting.

PubMed

Abdoli-Eramaki, Mohammad; Stevenson, Joan M; Agnew, Michael J; Kamalzadeh, Amin

2009-04-01

The purpose of this study was to validate a 3D dynamic virtual model for lifting tasks against a validated link segment model (LSM). A face validation study was conducted by collecting x, y, z coordinate data and using them in both virtual and LSM models. An upper body virtual model was needed to calculate the 3D torques about human joints for use in simulated lifting styles and to estimate the effect of external mechanical devices on human body. Firstly, the model had to be validated to be sure it provided accurate estimates of 3D moments in comparison to a previously validated LSM. Three synchronised Fastrak units with nine sensors were used to record data from one male subject who completed dynamic box lifting under 27 different load conditions (box weights (3), lifting techniques (3) and rotations (3)). The external moments about three axes of L4/L5 were compared for both models. A pressure switch on the box was used to denote the start and end of the lift. An excellent agreement [image omitted] was found between the two models for dynamic lifting tasks, especially for larger moments in flexion and extension. This virtual model was considered valid for use in a complete simulation of the upper body skeletal system. This biomechanical virtual model of the musculoskeletal system can be used by researchers and practitioners to give a better tool to study the causes of LBP and the effect of intervention strategies, by permitting the researcher to see and control a virtual subject's motions.

Thermal Analysis of a Carbon Fiber Rope Barrier for Use in the Reusable Solid Rocket Motor Nozzle Joint-2

NASA Technical Reports Server (NTRS)

Clayton, J. Louie

2002-01-01

This study provides development and verification of analysis methods used to assess performance of a carbon fiber rope (CFR) thermal barrier system that is currently being qualified for use in Reusable Solid Rocket Motor (RSRM) nozzle joint-2. Modeled geometry for flow calculations considers the joint to be vented with the porous CFR barriers placed in the 'open' assembly gap. Model development is based on a 1-D volume filling approach where flow resistances (assembly gap and CFRs) are defined by serially connected internal flow and the porous media 'Darcy' relationships. Combustion gas flow rates are computed using the volume filling code by assuming a lumped distribution total joint fill volume on a per linear circumferential inch basis. Gas compressibility, friction and heat transfer are included in the modeling. Gas-to-wall heat transfer is simulated by concurrent solution of the compressible flow equations and a large thermal 2-D finite element (FE) conduction grid. The derived numerical technique loosely couples the FE conduction matrix with the compressible gas flow equations. Free constants that appear in the governing equations are calibrated by parametric model comparison to hot fire subscale test results. The calibrated model is then used to make full-scale motor predictions using RSRM aft dome environments. Model results indicate that CFR thermal barrier systems will provide a thermally benign and controlled pressurization environment for the RSRM nozzle joint-2 primary seal activation.

Thermal Analysis of a Carbon Fiber Rope Barrier for Use in the Reusable Solid Rocket Motor Nozzle Joint-2

NASA Technical Reports Server (NTRS)

Clayton, J. Louie; Phelps, Lisa (Technical Monitor)

2001-01-01

This study provides for development and verification of analysis methods used to assess performance of a carbon fiber rope (CFR) thermal barrier system that is currently being qualified for use in Reusable Solid Rocket Motor (RSRM) nozzle joint-2. Modeled geometry for flow calculations considers the joint to be vented with the porous CFR barriers placed in the "open' assembly gap. Model development is based on a 1-D volume filling approach where flow resistances (assembly gap and CFRs) are defined by serially connected internal flow and the porous media "Darcy" relationships. Combustion gas flow rates are computed using the volume filling code by assuming a lumped distribution total joint fill volume on a per linear circumferential inch basis. Gas compressibility, friction and heat transfer are included in the modeling. Gas-to-wall heat transfer is simulated by concurrent solution of the compressible flow equations and a large thermal 2-D finite element (FE) conduction grid. The derived numerical technique loosely couples the FE conduction matrix with the compressible gas flow equations, Free constants that appear in the governing equations are calibrated by parametric model comparison to hot fire subscale test results. The calibrated model is then used to make full-scale motor predictions using RSRM aft dome environments. Model results indicate that CFR thermal barrier systems will provide a thermally benign and controlled pressurization environment for the RSRM nozzle joint-2 primary seal activation.

Structural modeling and optimization of a joined-wing configuration of a High-Altitude Long-Endurance (HALE) aircraft

NASA Astrophysics Data System (ADS)

Kaloyanova, Valentina B.

Recent research trends have indicated an interest in High-Altitude, Long-Endurance (HALE) aircraft as a low-cost alternative to certain space missions, such as telecommunication relay, environmental sensing and military reconnaissance. HALE missions require a light vehicle flying at low speed in the stratosphere at altitudes of 60,000-80,000 ft, with a continuous loiter time of up to several days. To provide high lift and low drag at these high altitudes, where the air density is low, the wing area should be increased, i.e., high-aspect-ratio wings are necessary. Due to its large span and lightweight, the wing structure is very flexible. To reduce the structural deformation, and increase the total lift in a long-spanned wing, a sensorcraft model with a joined-wing configuration, proposed by AFRL, is employed. The joined-wing encompasses a forward wing, which is swept back with a positive dihedral angle, and connected with an aft wing, which is swept forward. The joined-wing design combines structural strength, high aerodynamic performance and efficiency. As a first step to study the joined-wing structural behavior an 1-D approximation model is developed. The 1-D approximation is a simple structural model created using ANSYS BEAM4 elements to present a possible approach for the aerodynamics-structure coupling. The pressure loads from the aerodynamic analysis are integrated numerically to obtain the resultant aerodynamic forces and moments (spanwise lift and pitching moment distributions, acting at the aerodynamic center). These are applied on the 1-D structural model. A linear static analysis is performed under this equivalent load, and the deformed shape of the 1-D model is used to obtain the deformed shape of the actual 3-D joined wing, i.e. deformed aerodynamic surface grid. To date in the existing studies, only simplified structural models have been examined. In the present work, in addition to the simple 1-D beam model, a semi-monocoque structural model is developed. All stringers, skin panels, ribs and spars are represented by appropriate elements in a finite-element model. Also, the model accounts for the fuel weight and sensorcraft antennae housed within the wings. Linear and nonlinear static analyses under the aerodynamic load are performed. The stress distribution in the wing as well as deformation is explored. Starting with a structural model with uniform mass distribution, a design optimization is performed to achieve a fully stressed design. As the joined-wing structure is prone to buckling, after the design optimization is complete linear and nonlinear bucking analyses are performed to study the global joined-wing structural instability, the load magnitude at which it is expected to occur, and the buckling mode. The buckled shape of the aft wing (which is subjected to compression) is found to resemble that of a fixed-pinned column. The linear buckling analysis overestimates the buckling load. However, even the nonlinear buckling analysis results in a load factor higher than 3, i.e. the wing structure is buckling safe under its current loading conditions. As the region of the joint has a very complicated geometry that has adverse effects in the flow and stress behavior an independent, more finely meshed model (submodel) of the joint region is generated and analyzed. A detailed discussion of the stress distribution obtained in the joint region via the submodeling technique is presented in this study as well. It is found out that compared to its structural response, the joint adverse effects are much more pronounced in its aerodynamic response, so it is suggested for future studies the geometry of the joint to be optimized based on its aerodynamic performance. As this design and analysis study is aimed towards developing a realistic structural representation of the innovative joined-wing configuration, in addition to the "global", or upper-level optimization, a local level design optimization is performed as well. At the lower (local) level detailed models of wing structural panels are used to compute more complex failure modes and to design the details that are not included in the upper (global) level model. Proper coordination between local skin-stringer panel models and the global joined-wing model prevents inconsistency between the upper- (global) and lower- (local) level design models. (Abstract shortened by UMI.)

Design, analysis and verification of a knee joint oncological prosthesis finite element model.

PubMed

Zach, Lukáš; Kunčická, Lenka; Růžička, Pavel; Kocich, Radim

2014-11-01

The aim of this paper was to design a finite element model for a hinged PROSPON oncological knee endoprosthesis and to verify the model by comparison with ankle flexion angle using knee-bending experimental data obtained previously. Visible Human Project CT scans were used to create a general lower extremity bones model and to compose a 3D CAD knee joint model to which muscles and ligaments were added. Into the assembly the designed finite element PROSPON prosthesis model was integrated and an analysis focused on the PEEK-OPTIMA hinge pin bushing stress state was carried out. To confirm the stress state analysis results, contact pressure was investigated. The analysis was performed in the knee-bending position within 15.4-69.4° hip joint flexion range. The results showed that the maximum stress achieved during the analysis (46.6 MPa) did not exceed the yield strength of the material (90 MPa); the condition of plastic stability was therefore met. The stress state analysis results were confirmed by the distribution of contact pressure during knee-bending. The applicability of our designed finite element model for the real implant behaviour prediction was proven on the basis of good correlation of the analytical and experimental ankle flexion angle data. Copyright © 2014 Elsevier Ltd. All rights reserved.

ACL/MCL transection affects knee ligament insertion distance of healing and intact ligaments during gait in the Ovine model.

PubMed

Tapper, Janet E; Funakoshi, Yusei; Hariu, Mitsuhiro; Marchuk, Linda; Thornton, Gail M; Ronsky, Janet L; Zernicke, Ron; Shrive, Nigel G; Frank, Cyril B

2009-08-25

The objective of this study was to assess the impact of combined transection of the anterior cruciate and medial collateral ligaments on the intact and healing ligaments in the ovine stifle joint. In vivo 3D stifle joint kinematics were measured in eight sheep during treadmill walking (accuracy: 0.4+/-0.4mm, 0.4+/-0.4 degrees ). Kinematics were measured with the joint intact and at 2, 4, 8, 12, 16 and 20 weeks after either surgical ligament transection (n=5) or sham surgery without transection (n=3). After sacrifice at 20 weeks, the 3D subject-specific bone and ligament geometry were digitized, and the 3D distances between insertions (DBI) of ligaments during the dynamic in vivo motion were calculated. Anterior cruciate ligament/medial collateral ligament (ACL/MCL) transection resulted in changes in the DBI of not only the transected ACL, but also the intact lateral collateral ligament (LCL) and posterior cruciate ligament (PCL), while the DBI of the transected MCL was not significantly changed. Increases in the maximal ACL DBI (2 week: +4.2mm, 20 week: +5.7mm) caused increases in the range of ACL DBI (2 week: 3.6mm, 20 week: +3.8mm) and the ACL apparent strain (2 week: +18.9%, 20 week: +24.0%). Decreases in the minimal PCL DBI (2 week: -3.2mm, 20 week: -4.3mm) resulted in increases in the range of PCL DBI (2 week: +2.7mm, 20 week: +3.2mm). Decreases in the maximal LCL DBI (2 week: -1.0mm, 20 week: -2.0mm) caused decreased LCL apparent strain (2 week: -3.4%, 20 week: -6.9%). Changes in the mechanical environment of these ligaments may play a significant role in the biological changes observed in these ligaments.

A Method to Capture Macroslip at Bolted Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, Ronald Neil; Heitman, Lili Anne Akin

2015-10-01

Relative motion at bolted connections can occur for large shock loads as the internal shear force in the bolted connection overcomes the frictional resistive force. This macroslip in a structure dissipates energy and reduces the response of the components above the bolted connection. There is a need to be able to capture macroslip behavior in a structural dynamics model. A linear model and many nonlinear models are not able to predict marcoslip effectively. The proposed method to capture macroslip is to use the multi-body dynamics code ADAMS to model joints with 3-D contact at the bolted interfaces. This model includesmore » both static and dynamic friction. The joints are preloaded and the pinning effect when a bolt shank impacts a through hole inside diameter is captured. Substructure representations of the components are included to account for component flexibility and dynamics. This method was applied to a simplified model of an aerospace structure and validation experiments were performed to test the adequacy of the method.« less

A Method to Capture Macroslip at Bolted Interfaces [PowerPoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, Ronald Neil; Heitman, Lili Anne Akin

2016-01-01

Relative motion at bolted connections can occur for large shock loads as the internal shear force in the bolted connection overcomes the frictional resistive force. This macroslip in a structure dissipates energy and reduces the response of the components above the bolted connection. There is a need to be able to capture macroslip behavior in a structural dynamics model. A linear model and many nonlinear models are not able to predict marcoslip effectively. The proposed method to capture macroslip is to use the multi-body dynamics code ADAMS to model joints with 3-D contact at the bolted interfaces. This model includesmore » both static and dynamic friction. The joints are preloaded and the pinning effect when a bolt shank impacts a through hole inside diameter is captured. Substructure representations of the components are included to account for component flexibility and dynamics. This method was applied to a simplified model of an aerospace structure and validation experiments were performed to test the adequacy of the method.« less

26 CFR 1.6017-1 - Self-employment tax returns.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Revenue Service to such resident for use in lieu of Form 1040SS. (b) Joint returns. (1) In the case of a.... The requirement of section 6013(d)(3) that in the case of a joint return the tax is computed on the... tax in the case of a joint return is joint and several. (c) Social security account numbers. (1) Every...

Tibiofemoral and patellofemoral joint 3D-kinematics in patients with posterior cruciate ligament deficiency compared to healthy volunteers.

PubMed

von Eisenhart-Rothe, Ruediger; Lenze, Ulrich; Hinterwimmer, Stefan; Pohlig, Florian; Graichen, Heiko; Stein, Thomas; Welsch, Frederic; Burgkart, Rainer

2012-11-26

The posterior cruciate ligament (PCL) plays an important role in maintaining physiological kinematics and function of the knee joint. To date mainly in-vitro models or combined magnetic resonance and fluoroscopic systems have been used for quantifying the importance of the PCL. We hypothesized, that both tibiofemoral and patellofemoral kinematic patterns are changed in PCL-deficient knees, which is increased by isometric muscle flexion. Therefore the aim of this study was to simultaneously investigate tibiofemoral and patellofemoral 3D kinematics in patients suffering from PCL deficiency during different knee flexion angles and under neuromuscular activation. We enrolled 12 patients with isolated PCL-insufficiency as well as 20 healthy volunteers. Sagittal MR-images of the knee joint were acquired in different positions of the knee joint (0°, 30°, 90° flexion, with and without flexing isometric muscle activity) on a 0.2 Tesla open MR-scanner. After segmentation of the patella, femur and tibia local coordinate systems were established to define the spatial position of these structures in relation to each other. At full extension and 30° flexion no significant difference was observed in PCL-deficient knee joints neither for tibiofemoral nor for patellofemoral kinematics. At 90° flexion the femur of PCL-deficient patients was positioned significantly more anteriorly in relation to the tibia and both, the patellar tilt and the patellar shift to the lateral side, significantly increased compared to healthy knee joints. While no significant effect of isometric flexing muscle activity was observed in healthy individuals, in PCL-deficient knee joints an increased paradoxical anterior translation of the femur was observed at 90° flexion compared to the status of muscle relaxation. Significant changes in tibiofemoral and patellofemoral joint kinematics occur in patients with isolated PCL-insufficiency above 30 degrees of flexion compared to healthy volunteers. Since this could be one reasonable mechanism in the development of osteoarthritis (OA) our results might help to understand the long-term development of tibiofemoral and/or patellofemoral OA in PCL-insufficient knee joints.

The advantages of complementing MT profiles in 3-D environments with geomagnetic transfer function and interstation horizontal magnetic transfer function data: results from a synthetic case study

NASA Astrophysics Data System (ADS)

Campanyà, Joan; Ogaya, Xènia; Jones, Alan G.; Rath, Volker; Vozar, Jan; Meqbel, Naser

2016-12-01

As a consequence of measuring time variations of the electric and the magnetic field, which are related to current flow and charge distribution, magnetotelluric (MT) data in 2-D and 3-D environments are not only sensitive to the geoelectrical structures below the measuring points but also to any lateral anomalies surrounding the acquisition site. This behaviour complicates the characterization of the electrical resistivity distribution of the subsurface, particularly in complex areas. In this manuscript we assess the main advantages of complementing the standard MT impedance tensor (Z) data with interstation horizontal magnetic tensor (H) and geomagnetic transfer function (T) data in constraining the subsurface in a 3-D environment beneath a MT profile. Our analysis was performed using synthetic responses with added normally distributed and scattered random noise. The sensitivity of each type of data to different resistivity anomalies was evaluated, showing that the degree to which each site and each period is affected by the same anomaly depends on the type of data. A dimensionality analysis, using Z, H and T data, identified the presence of the 3-D anomalies close to the profile, suggesting a 3-D approach for recovering the electrical resistivity values of the subsurface. Finally, the capacity for recovering the geoelectrical structures of the subsurface was evaluated by performing joint inversion using different data combinations, quantifying the differences between the true synthetic model and the models from inversion process. Four main improvements were observed when performing joint inversion of Z, H and T data: (1) superior precision and accuracy at characterizing the electrical resistivity values of the anomalies below and outside the profile; (2) the potential to recover high electrical resistivity anomalies that are poorly recovered using Z data alone; (3) improvement in the characterization of the bottom and lateral boundaries of the anomalies with low electrical resistivity; and (4) superior imaging of the horizontal continuity of structures with low electrical resistivity. These advantages offer new opportunities for the MT method by making the results from a MT profile in a 3-D environment more convincing, supporting the possibility of high-resolution studies in 3-D areas without expending a large amount of economical and computational resources, and also offering better resolution of targets with high electrical resistivity.

Do depression and anxiety reduce the likelihood of remission in rheumatoid arthritis and psoriatic arthritis? Data from the prospective multicentre NOR-DMARD study.

PubMed

Michelsen, Brigitte; Kristianslund, Eirik Klami; Sexton, Joseph; Hammer, Hilde Berner; Fagerli, Karen Minde; Lie, Elisabeth; Wierød, Ada; Kalstad, Synøve; Rødevand, Erik; Krøll, Frode; Haugeberg, Glenn; Kvien, Tore K

2017-11-01

To investigate the predictive value of baseline depression/anxiety on the likelihood of achieving joint remission in rheumatoid arthritis (RA) and psoriatic arthritis (PsA) as well as the associations between baseline depression/anxiety and the components of the remission criteria at follow-up. We included 1326 patients with RA and 728 patients with PsA from the prospective observational NOR-DMARD study starting first-time tumour necrosis factor inhibitors or methotrexate. The predictive value of depression/anxiety on remission was explored in prespecified logistic regression models and the associations between baseline depression/anxiety and the components of the remission criteria in prespecified multiple linear regression models. Baseline depression/anxiety according to EuroQoL-5D-3L, Short Form-36 (SF-36) Mental Health subscale ≤56 and SF-36 Mental Component Summary ≤38 negatively predicted 28-joint Disease Activity Score <2.6, Simplified Disease Activity Index ≤3.3, Clinical Disease Activity Index ≤2.8, ACR/EULAR Boolean and Disease Activity Index for Psoriatic Arthritis ≤4 remission after 3 and 6 months treatment in RA (p≤0.008) and partly in PsA (p from 0.001 to 0.73). Baseline depression/anxiety was associated with increased patient's and evaluator's global assessment, tender joint count and joint pain in RA at follow-up, but not with swollen joint count and acute phase reactants. Depression and anxiety may reduce likelihood of joint remission based on composite scores in RA and PsA and should be taken into account in individual patients when making a shared decision on a treatment target. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A sensitivity analysis method for the body segment inertial parameters based on ground reaction and joint moment regressor matrices.

PubMed

Futamure, Sumire; Bonnet, Vincent; Dumas, Raphael; Venture, Gentiane

2017-11-07

This paper presents a method allowing a simple and efficient sensitivity analysis of dynamics parameters of complex whole-body human model. The proposed method is based on the ground reaction and joint moment regressor matrices, developed initially in robotics system identification theory, and involved in the equations of motion of the human body. The regressor matrices are linear relatively to the segment inertial parameters allowing us to use simple sensitivity analysis methods. The sensitivity analysis method was applied over gait dynamics and kinematics data of nine subjects and with a 15 segments 3D model of the locomotor apparatus. According to the proposed sensitivity indices, 76 segments inertial parameters out the 150 of the mechanical model were considered as not influent for gait. The main findings were that the segment masses were influent and that, at the exception of the trunk, moment of inertia were not influent for the computation of the ground reaction forces and moments and the joint moments. The same method also shows numerically that at least 90% of the lower-limb joint moments during the stance phase can be estimated only from a force-plate and kinematics data without knowing any of the segment inertial parameters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of dowel bar looseness on measured load transfer efficiency using FWD load

NASA Astrophysics Data System (ADS)

Shoukry, Samir N.; William, Gergis W.; Riad, Mourad Y.

2001-07-01

The effect of dowel bar looseness on the joint load transfer efficiency using Falling Weight Deflectometer is the subject of this paper. The mechanism of dynamic load transfer at transverse joints of Jointed Plain Concrete Pavement is examined using nonlinear 3D finite element analysis.

The impact of severe haemophilia and the presence of target joints on health-related quality-of-life.

PubMed

O'Hara, Jamie; Walsh, Shaun; Camp, Charlotte; Mazza, Giuseppe; Carroll, Liz; Hoxer, Christina; Wilkinson, Lars

2018-05-02

Joint damage remains a major complication associated with haemophilia and is widely accepted as one of the most debilitating symptoms for persons with severe haemophilia. The aim of this study is to describe how complications of haemophilia such as target joints influence health-related quality of life (HRQOL). Data on hemophilia patients without inhibitors were drawn from the 'Cost of Haemophilia across Europe - a Socioeconomic Survey' (CHESS) study, a cost-of-illness assessment in severe haemophilia A and B across five European countries (France, Germany, Italy, Spain, and the UK). Physicians provided clinical and sociodemographic information for 1285 adult patients, 551 of whom completed corresponding questionnaires, including EQ-5D. A generalised linear model was developed to investigate the relationship between EQ-5D index score and target joint status (defined in the CHESS study as areas of chronic synovitis), adjusted for patient covariates including socio-demographic characteristics and comorbidities. Five hundred and fifteen patients (42% of the sample) provided an EQ-5D response; a total of 692 target joints were recorded across the sample. Mean EQ-5D index score for patients with no target joints was 0.875 (standard deviation [SD] 0.179); for patients with one or more target joints, mean index score was 0.731 (SD 0.285). Compared to having no target joints, having one or more target joints was associated with lower index scores (average marginal effect (AME) -0.120; SD 0.0262; p < 0.000). This study found that the presence of chronic synovitis has a significant negative impact on HRQOL for adults with severe haemophilia. Prevention, early diagnosis and treatment of target joints should be an important consideration for clinicians and patients when managing haemophilia.

Seismic-geodynamic constraints on three-dimensional structure, vertical flow, and heat transfer in the mantle

USGS Publications Warehouse

Forte, A.M.; Woodward, R.L.

1997-01-01

Joint inversions of seismic and geodynamic data are carried out in which we simultaneously constrain global-scale seismic heterogeneity in the mantle as well as the amplitude of vertical mantle flow across the 670 km seismic discontinuity. These inversions reveal the existence of a family of three-dimensional (3-D) mantle models that satisfy the data while at the same time yielding predictions of layered mantle flow. The new 3-D mantle models we obtain demonstrate that the buoyancy forces due to the undulations of the 670 km phase-change boundary strongly inhibit the vertical flow between the upper and lower mantle. The strong stabilizing effect of the 670 km topography also has an important impact on the predicted dynamic topography of the Earth's solid surface and on the surface gravity anomalies. The new 3-D models that predict strongly or partially layered mantle flow provide essentially identical fits to the global seismic data as previous models that have, until now, predicted only whole-mantle flow. The convective vertical transport of heat across the mantle predicted on the basis of the new 3-D models shows that the heat flow is a minimum at 1000 km depth. This suggests the presence at this depth of a globally defined horizon across which the pattern of lateral heterogeneity changes rapidly. Copyright 1997 by the American Geophysical Union.

Improved Modeling of Structural Joint Damping

DTIC Science & Technology

1986-12-01

fourth order beam equation. Griffel has tabulated the results for a number of beam loading geometries and, as seen in Figure 2-11, has plotted the shear... Griffel . Having the solution to the built-in beam symmetric case we can now move on to the development of the Boundary Element theory. 2.3 indirect...December 1985. 9. Greenwood, D. T., Principle? &t PY"affllC3/ New Jersey, Prentice-Hall, Inc., 1965. 10. Griffel , William, Beam Formulas. New York

The effect of fixed charge density and cartilage swelling on mechanics of knee joint cartilage during simulated gait.

PubMed

Räsänen, Lasse P; Tanska, Petri; Zbýň, Štefan; van Donkelaar, Corrinus C; Trattnig, Siegfried; Nieminen, Miika T; Korhonen, Rami K

2017-08-16

The effect of swelling of articular cartilage, caused by the fixed charge density (FCD) of proteoglycans, has not been demonstrated on knee joint mechanics during simulated walking before. In this study, the influence of the depth-wise variation of FCD was investigated on the internal collagen fibril strains and the mechanical response of the knee joint cartilage during gait using finite element (FE) analysis. The FCD distribution of tibial cartilage was implemented from sodium ( 23 Na) MRI into a 3-D FE-model of the knee joint ("Healthy model"). For comparison, models with decreased FCD values were created according to the decrease in FCD associated with the progression of osteoarthritis (OA) ("Early OA" and "Advanced OA" models). In addition, a model without FCD was created ("No FCD" model). The effect of FCD was studied with five different collagen fibril network moduli of cartilage. Using the reference fibril network moduli, the decrease in FCD from "Healthy model" to "Early OA" and "Advanced OA" models resulted in increased axial strains (by +2 and +6%) and decreased fibril strains (by -3 and -13%) throughout the stance, respectively, calculated as mean values through cartilage depth in the tibiofemoral contact regions. Correspondingly, compared to the "Healthy model", the removal of the FCD altogether in "NoFCD model" resulted in increased mean axial strains by +16% and decreased mean fibril strains by -24%. This effect was amplified as the fibril network moduli were decreased by 80% from the reference. Then mean axial strains increased by +6, +19 and +49% and mean fibril strains decreased by -9, -20 and -32%, respectively. Our results suggest that the FCD in articular cartilage has influence on cartilage responses in the knee during walking. Furthermore, the FCD is suggested to have larger impact on cartilage function as the collagen network degenerates e.g. in OA. Copyright © 2017 Elsevier Ltd. All rights reserved.

Three dimensional finite element analysis of the influence of posterior tibial slope on the anterior cruciate ligament and knee joint forward stability.

PubMed

Qi, Yong; Sun, Hongtao; Fan, Yueguang; Li, Feimeng; Wang, Yunting; Ge, Chana

2018-03-23

To explore the biomechanical influence of posterior tibial angle on the anterior cruciate ligament and knee joint forward stability. The left knee joint of a healthy volunteer was scanned by CT and MRI. The data were imported into Mimics software to obtain 3D models of bone, cartilage, meniscus and ligament structures, and then Geomagic software was used to modify of the image. The relative displacement between tibia and femur and the stress of ACL were recorded. ACL tension was 12.195 N in model with 2∘ PTS, 12.639 N in model with 7∘ PTS, 18.658 N in model with 12∘ PTS. the relative displacement of the tibia and femur was 2.735 mm in model with 2∘ PTS, 3.086 mm in model with 7∘ PTS, 3.881 mm in model with 12∘ PTS. In the model with 30∘ flexion, the maximum tension of ACL was 24.585 N in model with 2∘ PTS, 25.612 N in model with 7∘ PTS, 31.481 N in model with 12∘ PTS. The relative displacement of the tibia and femur was 5.590 mm in model with 2∘ PTS, 6.721 mm in model with 7∘ PTS, 6.952 mm in model with 12∘ PTS. In the 90∘ flexion models, ACL tension was 5.119 N in model with 2∘ PTS, 8.674 N in model with 7∘ PTS, 9.314 N in model with 12∘ PTS. The relative displacement of the tibia and femur was 0.276 mm in model with 2∘ PTS, 0.577 mm in model with 7∘ PTS, 0.602 mm in model with 12∘ PTS. The steeper PTS may be a risk factor in ACL injury.

A Global Upper-Mantle Tomographic Model of Shear Attenuation

NASA Astrophysics Data System (ADS)

Karaoglu, H.; Romanowicz, B. A.

2016-12-01

Mapping anelastic 3D structure within the earth's mantle is key to understanding present day mantle dynamics, as it provides complementary constraints to those obtained from elastic structure, with the potential to distinguish between thermal and compositional heterogeneity. For this, we need to measure seismic wave amplitudes, which are sensitive to both elastic (through focusing and scattering) and anelastic structure. The elastic effects are less pronounced at long periods, so previous global upper-mantle attenuation models are based on teleseismic surface wave data, sometimes including overtones. In these studies, elastic effects are considered either indirectly, by eliminating data strongly contaminated by them (e.g. Romanowicz, 1995; Gung and Romanowicz, 2004), or by correcting for elastic focusing effects using an approximate linear approach (Dalton et al., 2008). Additionally, in these studies, the elastic structure is held fixed when inverting for intrinsic attenuation . The importance of (1) having a good starting elastic model, (2) accurate modeling of the seismic wavefield and (3) joint inversion for elastic and anelastic structure, becomes more evident as the targeted resolution level increases. Also, velocity dispersion effects due to anelasticity need to be taken into account. Here, we employ a hybrid full waveform inversion method, inverting jointly for global elastic and anelastic upper mantle structure, starting from the latest global 3D shear velocity model built by our group (French and Romanowicz, 2014), using the spectral element method for the forward waveform modeling (Capdeville et al., 2003), and normal-mode perturbation theory (NACT - Li and Romanowicz, 1995) for kernel computations. We present a 3D upper-mantle anelastic model built by using three component fundamental and overtone surface waveforms down to 60 s as well as long period body waveforms down to 30 s. We also include source and site effects to first order as frequency independent scalar factors. The robustness of the inversion method is assessed through synthetic and resolution tests. We discuss salient features of the resulting anelastic model and in particular the well-resolved strong correlation with tectonics observed in the first 200 km of the mantle.

2D and 3D separate and joint inversion of airborne ZTEM and ground AMT data: Synthetic model studies

NASA Astrophysics Data System (ADS)

Sasaki, Yutaka; Yi, Myeong-Jong; Choi, Jihyang

2014-05-01

The ZTEM (Z-axis Tipper Electromagnetic) method measures naturally occurring audio-frequency magnetic fields and obtains the tipper function that defines the relationship among the three components of the magnetic field. Since the anomalous tipper responses are caused by the presence of lateral resistivity variations, the ZTEM survey is most suited for detecting and delineating conductive bodies extending to considerable depths, such as graphitic dykes encountered in the exploration of unconformity type uranium deposit. Our simulations shows that inversion of ZTEM data can detect reasonably well multiple conductive dykes placed 1 km apart. One important issue regarding ZTEM inversion is the effect of the initial model, because homogeneous half-space and (1D) layered structures produce no responses. For the 2D model with multiple conductive dykes, the inversion results were useful for locating the dykes even when the initial model was not close to the true background resistivity. For general 3D structures, however, the resolution of the conductive bodies can be reduced considerably depending on the initial model. This is because the tipper magnitudes from 3D conductors are smaller due to boundary charges than the 2D responses. To alleviate this disadvantage of ZTEM surveys, we combined ZTEM and audio-frequency magnetotelluric (AMT) data. Inversion of sparse AMT data was shown to be effective in providing a good initial model for ZTEM inversion. Moreover, simultaneously inverting both data sets led to better results than the sequential approach by enabling to identify structural features that were difficult to resolve from the individual data sets.

Severity mapping of the proximal femur: a new method for assessing hip osteoarthritis with computed tomography.

PubMed

Turmezei, T D; Lomas, D J; Hopper, M A; Poole, K E S

2014-10-01

Plain radiography has been the mainstay of imaging assessment in osteoarthritis for over 50 years, but it does have limitations. Here we present the methodology and results of a new technique for identifying, grading, and mapping the severity and spatial distribution of osteoarthritic disease features at the hip in 3D with clinical computed tomography (CT). CT imaging of 456 hips from 230 adult female volunteers (mean age 66 ± 17 years) was reviewed using 3D multiplanar reformatting to identify bone-related radiological features of osteoarthritis, namely osteophytes, subchondral cysts and joint space narrowing. Scoresheets dividing up the femoral head, head-neck region and the joint space were used to register the location and severity of each feature (scored from 0 to 3). Novel 3D cumulative feature severity maps were then created to display where the most severe disease features from each individual were anatomically located across the cohort. Feature severity maps showed a propensity for osteophytes at the inferoposterior and superolateral femoral head-neck junction. Subchondral cysts were a less common and less localised phenomenon. Joint space narrowing <1.5 mm was recorded in at least one sector of 83% of hips, but most frequently in the posterolateral joint space. This is the first description of hip osteoarthritis using unenhanced clinical CT in which we describe the co-localisation of posterior osteophytes and joint space narrowing for the first time. We believe this technique can perform several important roles in future osteoarthritis research, including phenotyping and sensitive disease assessment in 3D. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Comparison of 2 fluid ingress/egress systems for canine stifle arthroscopy using computed tomography.

PubMed

Warnock, Jennifer J; Nemanic, Sarah; O'Donnell, Matthew D; Wiest, Jason E

2014-11-01

To evaluate volume of extra-articular fluid egress and complications associated with 2 fluid ingress/egress techniques for stifle arthroscopy. Ex vivo study. Canine cadavers (n = 14). Four cadavers (8 stifles) were used to validate 3D computed tomographic (CT) methods to quantify stifle joint intra- and extra-articular volumes of iodinated contrast medium. Ten canine cadavers (20 stifles) had preoperative CT, followed by stifle arthroscopy using a 10% solution of iodinated contrast enhanced ingress fluid delivered by pressure bag (2PB) or by arthroscopic peristaltic pump (3FP). All 3FP limbs had an additional fluid egress portal placed by cannula and obturator. Arthroscopy was limited to 20 minutes/joint. The volume of the contrast medium egress into the soft tissues was measured on postoperative 3D CT reconstructed images. Mean percentage of total ingress fluids administered that remained in the joint and extra-articular tissues postoperatively was 8.8 ± 1.2% in 3FP and 33.2 ± 8% in 2PB (P = .014). Two 3FP joints had 4-5 mm egress obturator tracks on the proximal medial trochlear ridge. Two 2PB joints had severe joint collapse from extracapsular fluid precluding further examination. Intermittent visual blurring by joint fluid mixing or fat pad fragmentation/dissolution was noted in 2PB joints. A superior technique was not identified: 2PB had greater egress fluid tissue accumulation, whereas 3FP had better viewing of intra-articular structures with less tissue egress fluid accumulation; however, cartilage damage was induced with the egress obturator. © Copyright 2014 by The American College of Veterinary Surgeons.

Correlating PMC-MMC Bonded Joint 3D FEA with Test

NASA Technical Reports Server (NTRS)

Jacobson, Mindy; Rodini, Benjamin; Chen, Wayne C.; Flom, Yury A.; Posey, Alan J.

2005-01-01

A viewgraph presentation on the correlation of Polymer Matrix Composites (PMC) and Metal Matrix Composites (MMC) bonded joints using three dimensional finite element analyses with materials tests is shown.

Introgression of an imidazolinone-resistance gene from winter wheat (Triticum aestivum L.) into jointed goatgrass (Aegilops cylindrica Host).

PubMed

Perez-Jones, Alejandro; Mallory-Smith, Carol A; Hansen, Jennifer L; Zemetra, Robert S

2006-12-01

Imidazolinone-resistant winter wheat (Triticum aestivum L.) is being commercialized in the USA. This technology allows wheat growers to selectively control jointed goatgrass (Aegilops cylindrica Host), a weed that is especially problematic because of its close genetic relationship with wheat. However, the potential movement of the imidazolinone-resistance gene from winter wheat to jointed goatgrass is a concern. Winter wheat and jointed goatgrass have the D genome in common and can hybridize and backcross under natural field conditions. Since the imidazolinone-resistance gene (Imi1) is located on the D genome, it is possible for resistance to be transferred to jointed goatgrass via hybridization and backcrossing. To study the potential for gene movement, BC(2)S(2) plants were produced artificially using imidazolinone-resistant winter wheat (cv. FS-4) as the female parent and a native jointed goatgrass collection as the male recurrent parent. FS-4, the jointed goatgrass collection, and 18 randomly selected BC(2)S(2) populations were treated with imazamox. The percentage of survival was 100% for the FS-4, 0% for the jointed goatgrass collection and 6 BC(2)S(2) populations, 40% or less for 2 BC(2)S(2) populations, and 50% or greater for the remaining 10 BC(2)S(2) populations. Chromosome counts in BC(2)S(3) plants showed a restoration of the chromosome number of jointed goatgrass, with four out of four plants examined having 28 chromosomes. Sequencing of AHASL1D in BC(2)S(3) plants derived from BC(2)S(2)-6 revealed the sexual transmission of Imi1 from FS-4 to jointed goatgrass. Imi1 conferred resistance to the imidazolinone herbicide imazamox, as shown by the in vitro assay for acetohydroxyacid synthase (AHAS) activity.

A 3D finite element model to investigate prosthetic interface stresses of different posterior tibial slope.

PubMed

Shen, Yi; Li, Xiaomiao; Fu, Xiaodong; Wang, Weili

2015-11-01

Posterior tibial slope that is created during proximal tibial resection in total knee arthroplasty has emerged as an important factor in the mechanics of the knee joint and the surgical outcome. But the ideal degree of posterior tibial slope for recovery of the knee joint function and preventions of complications remains controversial and should vary in different racial groups. The objective of this paper is to investigate the effects of posterior tibial slope on contact stresses in the tibial polyethylene component of total knee prostheses. Three-dimensional finite element analysis was used to calculate contact stresses in tibial polyethylene component of total knee prostheses subjected to a compressive load. The 3D finite element model of total knee prosthesis was constructed from the images produced by 3D scanning technology. Stresses in tibial polyethylene component were calculated with four different posterior tibial slopes (0°, 3°, 6° and 9°). The 3D finite element model of total knee prosthesis we presented was well validated. We found that the stress distribution in the polythene as evaluated by the distributions of the von Mises stress, the maximum principle stress, the minimum principle stress and the Cpress were more uniform with 3° and 6° posterior tibial slopes than with 0° and 9° posterior tibial slopes. Moreover, the peaks of the above stresses and trends of changes with increasing degree of knee flexion were more ideal with 3° and 6° posterior slopes. The results suggested that the tibial component inclination might be favourable to 7°-10° so far as the stress distribution is concerned. The range of the tibial component inclination also can decrease the wear of polyethylene. Chinese posterior tibial slope is bigger than in the West, and the current domestic use of prostheses is imported from the West, so their demands to tilt back bone cutting can lead to shorten the service life of prostheses; this experiment result is of important clinical significance, guiding orthopaedic surgeon after the best angle to cut bone.

A Novel Approach for the Identification of Pharmacophores Through Differential Toxicity Analysis of Estrogen Receptor Positive and Negative Cell Lines

DTIC Science & Technology

2009-07-01

Associate Professor of Medicine with a joint appointment as Associate Professor of Pharmacology and Toxicology at the University of Louisville’s...pharmacophores for later 3-D QSAR modeling. Moreover, from a practical point, models of atom size 12 had roughly nearly 200,000 fragments wherein size...performed in general, one can consider the “accuracy” or reproducibility of a standard in vitro toxicological test. For instance, the US National Toxicology

A Cyberspace Command and Control Model

DTIC Science & Technology

2009-02-17

control of Commander, Joint Functional Component Commander – Network Warfare (JFCC-NW).3 This arrangement further creates gaps and seams as the DoD...technological advances and increases in the use and pervasiveness of cyberspace coupled with aggressive 5 adversaries create a volatile environment. Both...intrusions, combine to create an environment of frustrating ambiguity. The correct military response lies in establishing a C2 structure for this

Type synthesis and preliminary design of devices supporting lower limb's rehabilitation.

PubMed

Olinski, Michał; Lewandowski, Bogusz; Gronowicz, Antoni

2015-01-01

Based on the analysis of existing solutions, biomechanics of human lower limbs and anticipated applications, results of con- siderations concerning the necessary number of degrees of freedom for the designed device supporting rehabilitation of lower extremities are presented. An analysis was carried out in order to determine the innovative kinematic structure of the device, ensuring sufficient mobility and functionality while minimizing the number of degrees of freedom. With the aid of appropriate formalised meth- ods, for instance, type synthesis, a complete variety of solutions for leg joints were obtained in the form of basic and kinematic schemes, having the potential to find application in devices supporting lower limb rehabilitation. A 3D model of ankle joint module was built in Autodesk Inventor System, then imported to Adams and assembled into a moving numerical model of a mechanism. Several conducted simulations resulted in finding the required maximum stroke of the cylinders. A comparison of the angular ranges of ankle joint and similar devices with the ones achieved by the designed device indicated a sufficient reserve allowing not only movements typical of gait, but approximately achieving the passive range of motion for the ankle joint.

Effect of changes of femoral offset on abductor and joint reaction forces in total hip arthroplasty.

PubMed

Rüdiger, Hannes A; Guillemin, Maïka; Latypova, Adeliya; Terrier, Alexandre

2017-11-01

Anatomical reconstruction in total hip arthroplasty (THA) allows for physiological muscle function, good functional outcome and implant longevity. Quantitative data on the effect of a loss or gain of femoral offset (FO) are scarce. The aim of this study was to quantitatively describe the effect of FO changes on abductor moment arms, muscle and joint reactions forces. THA was virtually performed on 3D models built from preoperative CT scans of 15 patients undergoing THA. Virtual THA was performed with a perfectly anatomical reconstruction, a loss of 20% of FO (-FO), and a gain of 20% of FO (+FO). These models were combined with a generic musculoskeletal model (OpenSim) to predict moment arms, muscle and joint reaction forces during normal gait cycles. In average, with -FO reconstructions, muscle moment arms decreased, while muscle and hip forces increased significantly (p < 0.001). We observed the opposite with +FO reconstructions. Gluteus medius was more affected than gluteus minimus. -FO had more effect than +FO. A change of 20% of FO induced an average change 8% of abductor moment arms, 16% of their forces, and 6% of the joint reaction force. To our knowledge, this is the first report providing quantitative data on the effect of FO changes on muscle and joint forces during normal gait. A decrease of FO necessitates an increase of abductor muscle force to maintain normal gait, which in turn increases the joint reaction force. This effect underscores the importance of an accurate reconstruction of the femoral offset.

Joint Stochastic Inversion of Pre-Stack 3D Seismic Data and Well Logs for High Resolution Hydrocarbon Reservoir Characterization

NASA Astrophysics Data System (ADS)

Torres-Verdin, C.

2007-05-01

This paper describes the successful implementation of a new 3D AVA stochastic inversion algorithm to quantitatively integrate pre-stack seismic amplitude data and well logs. The stochastic inversion algorithm is used to characterize flow units of a deepwater reservoir located in the central Gulf of Mexico. Conventional fluid/lithology sensitivity analysis indicates that the shale/sand interface represented by the top of the hydrocarbon-bearing turbidite deposits generates typical Class III AVA responses. On the other hand, layer- dependent Biot-Gassmann analysis shows significant sensitivity of the P-wave velocity and density to fluid substitution. Accordingly, AVA stochastic inversion, which combines the advantages of AVA analysis with those of geostatistical inversion, provided quantitative information about the lateral continuity of the turbidite reservoirs based on the interpretation of inverted acoustic properties (P-velocity, S-velocity, density), and lithotype (sand- shale) distributions. The quantitative use of rock/fluid information through AVA seismic amplitude data, coupled with the implementation of co-simulation via lithotype-dependent multidimensional joint probability distributions of acoustic/petrophysical properties, yields accurate 3D models of petrophysical properties such as porosity and permeability. Finally, by fully integrating pre-stack seismic amplitude data and well logs, the vertical resolution of inverted products is higher than that of deterministic inversions methods.

Applying Simulated In Vivo Motions to Measure Human Knee and ACL Kinetics

PubMed Central

Herfat, Safa T.; Boguszewski, Daniel V.; Shearn, Jason T.

2013-01-01

Patients frequently experience anterior cruciate ligament (ACL) injuries but current ACL reconstruction strategies do not restore the native biomechanics of the knee, which can contribute to the early onset of osteoarthritis in the long term. To design more effective treatments, investigators must first understand normal in vivo knee function for multiple activities of daily living (ADLs). While the 3D kinematics of the human knee have been measured for various ADLs, the 3D kinetics cannot be directly measured in vivo. Alternatively, the 3D kinetics of the knee and its structures can be measured in an animal model by simulating and applying subject-specific in vivo joint motions to a joint using robotics. However, a suitable biomechanical surrogate should first be established. This study was designed to apply a simulated human in vivo motion to human knees to measure the kinetics of the human knee and ACL. In pursuit of establishing a viable biomechanical surrogate, a simulated in vivo ovine motion was also applied to human knees to compare the loads produced by the human and ovine motions. The motions from the two species produced similar kinetics in the human knee and ACL. The only significant difference was the intact knee compression force produced by the two input motions. PMID:22227973

The application of 3D printed surgical guides in resection and reconstruction of malignant bone tumor.

PubMed

Wang, Fengping; Zhu, Jun; Peng, Xuejun; Su, Jing

2017-10-01

The clinical value of 3D printed surgical guides in resection and reconstruction of malignant bone tumor around the knee joint were studied. For this purpose, a sample of 66 patients from October 2013 to October 2015 were randomly selected and further divided into control group and observation group, each group consisted of 33 cases. The control group was treated by conventional tumor resection whereas, in the observation group, the tumor was resected with 3D printed surgical guide. However, reconstruction of tumor-type hinge prosthesis was performed in both groups and then the clinical effect was compared. Results show that there was no significant difference in the operation time between the two groups (p>0.05). However, the blood loss, resection length and complication rate were found significantly lower in the observation group than in the control group (p<0.05). The rate of negative margin and the recurrence rate in the 12-month follow-up (p>0.05) between two groups were statistically the same (p>0.05), whereas the Musculoskeletal Tumor Society (MSTS) score of the knee joint in the observation group was significantly better than that of the control group (p<0.05) after 1, 3, 6 and 12 months of the operation. Consequently, the 3D printed surgical guides can significantly improve the postoperative joint function after resection and reconstruction of malignant bone tumor around the knee joint and can reduce the incidence of complications.

Unambiguous determination of H-atom positions: comparing results from neutron and high-resolution X-ray crystallography.

PubMed

Gardberg, Anna S; Del Castillo, Alexis Rae; Weiss, Kevin L; Meilleur, Flora; Blakeley, Matthew P; Myles, Dean A A

2010-05-01

The locations of H atoms in biological structures can be difficult to determine using X-ray diffraction methods. Neutron diffraction offers a relatively greater scattering magnitude from H and D atoms. Here, 1.65 A resolution neutron diffraction studies of fully perdeuterated and selectively CH(3)-protonated perdeuterated crystals of Pyrococcus furiosus rubredoxin (D-rubredoxin and HD-rubredoxin, respectively) at room temperature (RT) are described, as well as 1.1 A resolution X-ray diffraction studies of the same protein at both RT and 100 K. The two techniques are quantitatively compared in terms of their power to directly provide atomic positions for D atoms and analyze the role played by atomic thermal motion by computing the sigma level at the D-atom coordinate in simulated-annealing composite D-OMIT maps. It is shown that 1.65 A resolution RT neutron data for perdeuterated rubredoxin are approximately 8 times more likely overall to provide high-confidence positions for D atoms than 1.1 A resolution X-ray data at 100 K or RT. At or above the 1.0sigma level, the joint X-ray/neutron (XN) structures define 342/378 (90%) and 291/365 (80%) of the D-atom positions for D-rubredoxin and HD-rubredoxin, respectively. The X-ray-only 1.1 A resolution 100 K structures determine only 19/388 (5%) and 8/388 (2%) of the D-atom positions above the 1.0sigma level for D-rubredoxin and HD-rubredoxin, respectively. Furthermore, the improved model obtained from joint XN refinement yielded improved electron-density maps, permitting the location of more D atoms than electron-density maps from models refined against X-ray data only.

Quantifying the tibiofemoral joint space using x-ray tomosynthesis.

PubMed

Kalinosky, Benjamin; Sabol, John M; Piacsek, Kelly; Heckel, Beth; Gilat Schmidt, Taly

2011-12-01

Digital x-ray tomosynthesis (DTS) has the potential to provide 3D information about the knee joint in a load-bearing posture, which may improve diagnosis and monitoring of knee osteoarthritis compared with projection radiography, the current standard of care. Manually quantifying and visualizing the joint space width (JSW) from 3D tomosynthesis datasets may be challenging. This work developed a semiautomated algorithm for quantifying the 3D tibiofemoral JSW from reconstructed DTS images. The algorithm was validated through anthropomorphic phantom experiments and applied to three clinical datasets. A user-selected volume of interest within the reconstructed DTS volume was enhanced with 1D multiscale gradient kernels. The edge-enhanced volumes were divided by polarity into tibial and femoral edge maps and combined across kernel scales. A 2D connected components algorithm was performed to determine candidate tibial and femoral edges. A 2D joint space width map (JSW) was constructed to represent the 3D tibiofemoral joint space. To quantify the algorithm accuracy, an adjustable knee phantom was constructed, and eleven posterior-anterior (PA) and lateral DTS scans were acquired with the medial minimum JSW of the phantom set to 0-5 mm in 0.5 mm increments (VolumeRad™, GE Healthcare, Chalfont St. Giles, United Kingdom). The accuracy of the algorithm was quantified by comparing the minimum JSW in a region of interest in the medial compartment of the JSW map to the measured phantom setting for each trial. In addition, the algorithm was applied to DTS scans of a static knee phantom and the JSW map compared to values estimated from a manually segmented computed tomography (CT) dataset. The algorithm was also applied to three clinical DTS datasets of osteoarthritic patients. The algorithm segmented the JSW and generated a JSW map for all phantom and clinical datasets. For the adjustable phantom, the estimated minimum JSW values were plotted against the measured values for all trials. A linear fit estimated a slope of 0.887 (R² = 0.962) and a mean error across all trials of 0.34 mm for the PA phantom data. The estimated minimum JSW values for the lateral adjustable phantom acquisitions were found to have low correlation to the measured values (R² = 0.377), with a mean error of 2.13 mm. The error in the lateral adjustable-phantom datasets appeared to be caused by artifacts due to unrealistic features in the phantom bones. JSW maps generated by DTS and CT varied by a mean of 0.6 mm and 0.8 mm across the knee joint, for PA and lateral scans. The tibial and femoral edges were successfully segmented and JSW maps determined for PA and lateral clinical DTS datasets. A semiautomated method is presented for quantifying the 3D joint space in a 2D JSW map using tomosynthesis images. The proposed algorithm quantified the JSW across the knee joint to sub-millimeter accuracy for PA tomosynthesis acquisitions. Overall, the results suggest that x-ray tomosynthesis may be beneficial for diagnosing and monitoring disease progression or treatment of osteoarthritis by providing quantitative images of JSW in the load-bearing knee.

Comprehensive joint feedback control for standing by functional neuromuscular stimulation-a simulation study.

PubMed

Nataraj, Raviraj; Audu, Musa L; Kirsch, Robert F; Triolo, Ronald J

2010-12-01

Previous investigations of feedback control of standing after spinal cord injury (SCI) using functional neuromuscular stimulation (FNS) have primarily targeted individual joints. This study assesses the potential efficacy of comprehensive (trunk, hips, knees, and ankles) joint feedback control against postural disturbances using a bipedal, 3-D computer model of SCI stance. Proportional-derivative feedback drove an artificial neural network trained to produce muscle excitation patterns consistent with maximal joint stiffness values achievable about neutral stance given typical SCI muscle properties. Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances. Compared to the baseline case of maximum constant muscle excitations used clinically, the controller reduced UE loading by 55% in resisting external force perturbations and by 84% during simulated one-arm functional tasks. Performance was most sensitive to inaccurate measurements of ankle plantar/dorsiflexion position and hip ab/adduction velocity feedback. In conclusion, comprehensive joint feedback demonstrates potential to markedly improve FNS standing function. However, alternative control structures capable of effective performance with fewer sensor-based feedback parameters may better facilitate clinical usage.

3D printing of novel osteochondral scaffolds with graded microstructure

NASA Astrophysics Data System (ADS)

Nowicki, Margaret A.; Castro, Nathan J.; Plesniak, Michael W.; Zhang, Lijie Grace

2016-10-01

Osteochondral tissue has a complex graded structure where biological, physiological, and mechanical properties vary significantly over the full thickness spanning from the subchondral bone region beneath the joint surface to the hyaline cartilage region at the joint surface. This presents a significant challenge for tissue-engineered structures addressing osteochondral defects. Fused deposition modeling (FDM) 3D bioprinters present a unique solution to this problem. The objective of this study is to use FDM-based 3D bioprinting and nanocrystalline hydroxyapatite for improved bone marrow human mesenchymal stem cell (hMSC) adhesion, growth, and osteochondral differentiation. FDM printing parameters can be tuned through computer aided design and computer numerical control software to manipulate scaffold geometries in ways that are beneficial to mechanical performance without hindering cellular behavior. Additionally, the ability to fine-tune 3D printed scaffolds increases further through our investment casting procedure which facilitates the inclusion of nanoparticles with biochemical factors to further elicit desired hMSC differentiation. For this study, FDM was used to print investment-casting molds innovatively designed with varied pore distribution over the full thickness of the scaffold. The mechanical and biological impacts of the varied pore distributions were compared and evaluated to determine the benefits of this physical manipulation. The results indicate that both mechanical properties and cell performance improve in the graded pore structures when compared to homogeneously distributed porous and non-porous structures. Differentiation results indicated successful osteogenic and chondrogenic manipulation in engineered scaffolds.

Joint Tomographic Imaging of 3-­-D Density Structure Using Cosmic Ray Muons and High-­-Precision Gravity Data

NASA Astrophysics Data System (ADS)

Rowe, C. A.; Guardincerri, E.; Roy, M.; Dichter, M.

2015-12-01

As part of the CO2 reservoir muon imaging project headed by the Pacific Northwest National Laboraory (PNNL) under the U.S. Department of Energy Subsurface Technology and Engineering Research, Development, and Demonstration (SubTER) iniative, Los Alamos National Laboratory (LANL) and the University of New Mexico (UNM) plan to leverage the recently decommissioned and easily accessible Tunnel Vault on LANL property to test the complementary modeling strengths of muon radiography and high-precision gravity surveys. This tunnel extends roughly 300 feet into the hillside, with a maximum depth below the surface of approximately 300 feet. We will deploy LANL's Mini Muon Tracker (MMT), a detector consisting of 576 drift tubes arranged in alternating parallel planes of orthogonally oriented tubes. This detector is capable of precise determination of trajectories for incoming muons with angular resolution of a few milliradians. We will deploy the MMT at several locations within the tunnel, to obtain numerous crossing muon trajectories and permit a 3D tomographic image of the overburden to be built. In the same project, UNM will use a Scintrex digital gravimeter to collect high-precision gravity data from a dense grid on the hill slope above the tunnel as well as within the tunnel itself. This will provide both direct and differential gravity readings for density modeling of the overburden. By leveraging detailed geologic knowledge of the canyon and the lithology overlying the tunnel, as well as the structural elements, elevations and blueprints of the tunnel itself, we will evaluate the muon and gravity data both independently and in a simultaneous, joint inversion to build a combined 3D density model of the overburden.

Dual Quaternions as Constraints in 4D-DPM Models for Pose Estimation.

PubMed

Martinez-Berti, Enrique; Sánchez-Salmerón, Antonio-José; Ricolfe-Viala, Carlos

2017-08-19

The goal of this research work is to improve the accuracy of human pose estimation using the Deformation Part Model (DPM) without increasing computational complexity. First, the proposed method seeks to improve pose estimation accuracy by adding the depth channel to DPM, which was formerly defined based only on red-green-blue (RGB) channels, in order to obtain a four-dimensional DPM (4D-DPM). In addition, computational complexity can be controlled by reducing the number of joints by taking it into account in a reduced 4D-DPM. Finally, complete solutions are obtained by solving the omitted joints by using inverse kinematics models. In this context, the main goal of this paper is to analyze the effect on pose estimation timing cost when using dual quaternions to solve the inverse kinematics.

Realization of masticatory movement by 3-dimensional simulation of the temporomandibular joint and the masticatory muscles.

PubMed

Park, Jong-Tae; Lee, Jae-Gi; Won, Sung-Yoon; Lee, Sang-Hee; Cha, Jung-Yul; Kim, Hee-Jin

2013-07-01

Masticatory muscles are closely involved in mastication, pronunciation, and swallowing, and it is therefore important to study the specific functions and dynamics of the mandibular and masticatory muscles. However, the shortness of muscle fibers and the diversity of movement directions make it difficult to study and simplify the dynamics of mastication. The purpose of this study was to use 3-dimensional (3D) simulation to observe the functions and movements of each of the masticatory muscles and the mandible while chewing. To simulate the masticatory movement, computed tomographic images were taken from a single Korean volunteer (30-year-old man), and skull image data were reconstructed in 3D (Mimics; Materialise, Leuven, Belgium). The 3D-reconstructed masticatory muscles were then attached to the 3D skull model. The masticatory movements were animated using Maya (Autodesk, San Rafael, CA) based on the mandibular motion path. During unilateral chewing, the mandible was found to move laterally toward the functional side by contracting the contralateral lateral pterygoid and ipsilateral temporalis muscles. During the initial mouth opening, only hinge movement was observed at the temporomandibular joint. During this period, the entire mandible rotated approximately 13 degrees toward the bicondylar horizontal plane. Continued movement of the mandible to full mouth opening occurred simultaneously with sliding and hinge movements, and the mandible rotated approximately 17 degrees toward the center of the mandibular ramus. The described approach can yield data for use in face animation and other simulation systems and for elucidating the functional components related to contraction and relaxation of muscles during mastication.

Determination of consistent patterns of range of motion in the ankle joint with a computed tomography stress-test.

PubMed

Tuijthof, Gabriëlle Josephine Maria; Zengerink, Maartje; Beimers, Lijkele; Jonges, Remmet; Maas, Mario; van Dijk, Cornelis Niek; Blankevoort, Leendert

2009-07-01

Measuring the range of motion of the ankle joint can assist in accurate diagnosis of ankle laxity. A computed tomography-based stress-test (3D CT stress-test) was used that determines the three-dimensional position and orientation of tibial, calcaneal and talar bones. The goal was to establish a quantitative database of the normal ranges of motion of the talocrural and subtalar joints. A clinical case on suspected subtalar instability demonstrated the relevance the proposed method. The range of motion was measured for the ankle joints in vivo for 20 subjects using the 3D CT stress-test. Motion of the tibia and calcaneus relative to the talus for eight extreme foot positions were described by helical parameters. High consistency for finite helical axis orientation (n) and rotation (theta) was shown for: talocrural extreme dorsiflexion to extreme plantarflexion (root mean square direction deviation (eta) 5.3 degrees and theta: SD 11.0 degrees), talorucral and subtalar extreme combined eversion-dorsiflexion to combined inversion-plantarflexion (eta: 6.7 degrees , theta: SD 9.0 degrees and eta:6.3 degrees , theta: SD 5.1 degrees), and subtalar extreme inversion to extreme eversion (eta: 6.4 degrees, theta: SD 5.9 degrees). Nearly all dorsi--and plantarflexion occurs in the talocrural joint (theta: mean 63.3 degrees (SD 11 degrees)). The inversion and internal rotation components for extreme eversion to inversion were approximately three times larger for the subtalar joint (theta: mean 22.9 degrees and 29.1 degrees) than for the talocrural joint (theta: mean 8.8 degrees and 10.7 degrees). Comparison of the ranges of motion of the pathologic ankle joint with the healthy subjects showed an increased inversion and axial rotation in the talocrural joint instead of in the suspected subtalar joint. The proposed diagnostic technique and the acquired database of helical parameters of ankle joint ranges of motion are suitable to apply in clinical cases.

Three-dimensional reconstruction of rat knee joint using episcopic fluorescence image capture.

PubMed

Takaishi, R; Aoyama, T; Zhang, X; Higuchi, S; Yamada, S; Takakuwa, T

2014-10-01

Development of the knee joint was morphologically investigated, and the process of cavitation was analyzed by using episcopic fluorescence image capture (EFIC) to create spatial and temporal three-dimensional (3D) reconstructions. Knee joints of Wister rat embryos between embryonic day (E)14 and E20 were investigated. Samples were sectioned and visualized using an EFIC. Then, two-dimensional image stacks were reconstructed using OsiriX software, and 3D reconstructions were generated using Amira software. Cavitations of the knee joint were constructed from five divided portions. Cavity formation initiated at multiple sites at E17; among them, the femoropatellar cavity (FPC) was the first. Cavitations of the medial side preceded those of the lateral side. Each cavity connected at E20 when cavitations around the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were completed. Cavity formation initiated from six portions. In each portion, development proceeded asymmetrically. These results concerning anatomical development of the knee joint using EFIC contribute to a better understanding of the structural feature of the knee joint. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Comparison of 3D Joint Angles Measured With the Kinect 2.0 Skeletal Tracker Versus a Marker-Based Motion Capture System.

PubMed

Guess, Trent M; Razu, Swithin; Jahandar, Amirhossein; Skubic, Marjorie; Huo, Zhiyu

2017-04-01

The Microsoft Kinect is becoming a widely used tool for inexpensive, portable measurement of human motion, with the potential to support clinical assessments of performance and function. In this study, the relative osteokinematic Cardan joint angles of the hip and knee were calculated using the Kinect 2.0 skeletal tracker. The pelvis segments of the default skeletal model were reoriented and 3-dimensional joint angles were compared with a marker-based system during a drop vertical jump and a hip abduction motion. Good agreement between the Kinect and marker-based system were found for knee (correlation coefficient = 0.96, cycle RMS error = 11°, peak flexion difference = 3°) and hip (correlation coefficient = 0.97, cycle RMS = 12°, peak flexion difference = 12°) flexion during the landing phase of the drop vertical jump and for hip abduction/adduction (correlation coefficient = 0.99, cycle RMS error = 7°, peak flexion difference = 8°) during isolated hip motion. Nonsagittal hip and knee angles did not correlate well for the drop vertical jump. When limited to activities in the optimal capture volume and with simple modifications to the skeletal model, the Kinect 2.0 skeletal tracker can provide limited 3-dimensional kinematic information of the lower limbs that may be useful for functional movement assessment.

22 CFR 41.3 - Waiver by joint action of consular and immigration officers of passport and/or visa requirements.

Code of Federal Regulations, 2010 CFR

2010-04-01

... immigration officers of passport and/or visa requirements. 41.3 Section 41.3 Foreign Relations DEPARTMENT OF... Passport and Visas Not Required for Certain Nonimmigrants § 41.3 Waiver by joint action of consular and immigration officers of passport and/or visa requirements. Under the authority of INA 212(d)(4), the...

22 CFR 41.3 - Waiver by joint action of consular and immigration officers of passport and/or visa requirements.

Code of Federal Regulations, 2012 CFR

2012-04-01

... immigration officers of passport and/or visa requirements. 41.3 Section 41.3 Foreign Relations DEPARTMENT OF... Passport and Visas Not Required for Certain Nonimmigrants § 41.3 Waiver by joint action of consular and immigration officers of passport and/or visa requirements. Under the authority of INA 212(d)(4), the...

22 CFR 41.3 - Waiver by joint action of consular and immigration officers of passport and/or visa requirements.

Code of Federal Regulations, 2014 CFR

2014-04-01

... immigration officers of passport and/or visa requirements. 41.3 Section 41.3 Foreign Relations DEPARTMENT OF... Passport and Visas Not Required for Certain Nonimmigrants § 41.3 Waiver by joint action of consular and immigration officers of passport and/or visa requirements. Under the authority of INA 212(d)(4), the...

22 CFR 41.3 - Waiver by joint action of consular and immigration officers of passport and/or visa requirements.

Code of Federal Regulations, 2011 CFR

2011-04-01

... immigration officers of passport and/or visa requirements. 41.3 Section 41.3 Foreign Relations DEPARTMENT OF... Passport and Visas Not Required for Certain Nonimmigrants § 41.3 Waiver by joint action of consular and immigration officers of passport and/or visa requirements. Under the authority of INA 212(d)(4), the...

22 CFR 41.3 - Waiver by joint action of consular and immigration officers of passport and/or visa requirements.

Code of Federal Regulations, 2013 CFR

2013-04-01

... immigration officers of passport and/or visa requirements. 41.3 Section 41.3 Foreign Relations DEPARTMENT OF... Passport and Visas Not Required for Certain Nonimmigrants § 41.3 Waiver by joint action of consular and immigration officers of passport and/or visa requirements. Under the authority of INA 212(d)(4), the...

Joint Inversion of Body-Wave Arrival Times and Surface-Wave Dispersion Data in the Wavelet Domain Constrained by Sparsity Regularization

NASA Astrophysics Data System (ADS)

Zhang, H.; Fang, H.; Yao, H.; Maceira, M.; van der Hilst, R. D.

2014-12-01

Recently, Zhang et al. (2014, Pure and Appiled Geophysics) have developed a joint inversion code incorporating body-wave arrival times and surface-wave dispersion data. The joint inversion code was based on the regional-scale version of the double-difference tomography algorithm tomoDD. The surface-wave inversion part uses the propagator matrix solver in the algorithm DISPER80 (Saito, 1988) for forward calculation of dispersion curves from layered velocity models and the related sensitivities. The application of the joint inversion code to the SAFOD site in central California shows that the fault structure is better imaged in the new model, which is able to fit both the body-wave and surface-wave observations adequately. Here we present a new joint inversion method that solves the model in the wavelet domain constrained by sparsity regularization. Compared to the previous method, it has the following advantages: (1) The method is both data- and model-adaptive. For the velocity model, it can be represented by different wavelet coefficients at different scales, which are generally sparse. By constraining the model wavelet coefficients to be sparse, the inversion in the wavelet domain can inherently adapt to the data distribution so that the model has higher spatial resolution in the good data coverage zone. Fang and Zhang (2014, Geophysical Journal International) have showed the superior performance of the wavelet-based double-difference seismic tomography method compared to the conventional method. (2) For the surface wave inversion, the joint inversion code takes advantage of the recent development of direct inversion of surface wave dispersion data for 3-D variations of shear wave velocity without the intermediate step of phase or group velocity maps (Fang et al., 2014, Geophysical Journal International). A fast marching method is used to compute, at each period, surface wave traveltimes and ray paths between sources and receivers. We will test the new joint inversion code at the SAFOD site to compare its performance over the previous code. We will also select another fault zone such as the San Jacinto Fault Zone to better image its structure.

Novel Scalable 3-D MT Inverse Solver

NASA Astrophysics Data System (ADS)

Kuvshinov, A. V.; Kruglyakov, M.; Geraskin, A.

2016-12-01

We present a new, robust and fast, three-dimensional (3-D) magnetotelluric (MT) inverse solver. As a forward modelling engine a highly-scalable solver extrEMe [1] is used. The (regularized) inversion is based on an iterative gradient-type optimization (quasi-Newton method) and exploits adjoint sources approach for fast calculation of the gradient of the misfit. The inverse solver is able to deal with highly detailed and contrasting models, allows for working (separately or jointly) with any type of MT (single-site and/or inter-site) responses, and supports massive parallelization. Different parallelization strategies implemented in the code allow for optimal usage of available computational resources for a given problem set up. To parameterize an inverse domain a mask approach is implemented, which means that one can merge any subset of forward modelling cells in order to account for (usually) irregular distribution of observation sites. We report results of 3-D numerical experiments aimed at analysing the robustness, performance and scalability of the code. In particular, our computational experiments carried out at different platforms ranging from modern laptops to high-performance clusters demonstrate practically linear scalability of the code up to thousands of nodes. 1. Kruglyakov, M., A. Geraskin, A. Kuvshinov, 2016. Novel accurate and scalable 3-D MT forward solver based on a contracting integral equation method, Computers and Geosciences, in press.

Stiffness analysis of glued connection of the timber-concrete structure

NASA Astrophysics Data System (ADS)

Daňková, Jana; Mec, Pavel; Majstríková, Tereza

2016-01-01

This paper presents results of experimental and mathematical analysis of stiffness characteristics of a composite timber-concrete structure. The composite timberconcrete structure presented herein is non-typical compared to similar types of building structures. The interaction between the timber and concrete part of the composite cross-section is not based on metal connecting elements, but it is ensured by a glued-in perforated mesh made of plywood. The paper presents results of experimental and mathematical analysis for material alternatives of the solution of the glued joint. The slip modulus values were determined experimentally. Data obtained from the experiment evaluated by means of regression analysis. Test results were also used as input data for the compilation of a 3D model of a composite structure by means of the 3D finite element model. On the basis of result evaluation, it can be stated that the stress-deformation behaviour at shear loading of this specific timber-concrete composite structure can be affected by the type of glue used. Parameters of the 3D model of both alternative of the structure represent well the behaviour of the composite structure and the model can be used for predicting design parameters of a building structure.

Lithospheric structure of Taiwan from gravity modelling and sequential inversion of seismological and gravity data

NASA Astrophysics Data System (ADS)

Masson, F.; Mouyen, M.; Hwang, C.; Wu, Y.-M.; Ponton, F.; Lehujeur, M.; Dorbath, C.

2012-11-01

Using a Bouguer anomaly map and a dense seismic data set, we have performed two studies in order to improve our knowledge of the deep structure of Taiwan. First, we model the Bouguer anomaly along a profile crossing the island using simple forward modelling. The modelling is 2D, with the hypothesis of cylindrical symmetry. Second we present a joint analysis of gravity anomaly and seismic arrival time data recorded in Taiwan. An initial velocity model has been obtained by local earthquake tomography (LET) of the seismological data. The LET velocity model was used to construct an initial 3D gravity model, using a linear velocity-density relationship (Birch's law). The synthetic Bouguer anomaly calculated for this model has the same shape and wavelength as the observed anomaly. However some characteristics of the anomaly map are not retrieved. To derive a crustal velocity/density model which accounts for both types of observations, we performed a sequential inversion of seismological and gravity data. The variance reduction of the arrival time data for the final sequential model was comparable to the variance reduction obtained by simple LET. Moreover, the sequential model explained about 80% of the observed gravity anomaly. New 3D model of Taiwan lithosphere is presented.

Department of Defense Annual Report on Sexual Assault in the Military: Fiscal Year 2015

DTIC Science & Technology

2016-05-02

51 List of Figures Figure 1: DoD Social Ecological Model...across the Joint Force understands their role in upholding ethical standards of behavior as a way to prevent sexual assault. Sexual Assault...strategy execution at all subordinate levels of the military social environment (Figure 1). Figure 1: DoD Social Ecological Model Incorporated DoD

Resolution analysis of finite fault source inversion using one- and three-dimensional Green's functions 2. Combining seismic and geodetic data

USGS Publications Warehouse

Wald, D.J.; Graves, R.W.

2001-01-01

Using numerical tests for a prescribed heterogeneous earthquake slip distribution, we examine the importance of accurate Green's functions (GF) for finite fault source inversions which rely on coseismic GPS displacements and leveling line uplift alone and in combination with near-source strong ground motions. The static displacements, while sensitive to the three-dimensional (3-D) structure, are less so than seismic waveforms and thus are an important contribution, particularly when used in conjunction with waveform inversions. For numerical tests of an earthquake source and data distribution modeled after the 1994 Northridge earthquake, a joint geodetic and seismic inversion allows for reasonable recovery of the heterogeneous slip distribution on the fault. In contrast, inaccurate 3-D GFs or multiple 1-D GFs allow only partial recovery of the slip distribution given strong motion data alone. Likewise, using just the GPS and leveling line data requires significant smoothing for inversion stability, and hence, only a blurred vision of the prescribed slip is recovered. Although the half-space approximation for computing the surface static deformation field is no longer justifiable based on the high level of accuracy for current GPS data acquisition and the computed differences between 3-D and half-space surface displacements, a layered 1-D approximation to 3-D Earth structure provides adequate representation of the surface displacement field. However, even with the half-space approximation, geodetic data can provide additional slip resolution in the joint seismic and geodetic inversion provided a priori fault location and geometry are correct. Nevertheless, the sensitivity of the static displacements to the Earth structure begs caution for interpretation of surface displacements, particularly those recorded at monuments located in or near basin environments. Copyright 2001 by the American Geophysical Union.

Three-Dimensional Assessment of Temporomandibular Joint Using MRI-CBCT Image Registration

PubMed Central

Lagravere, Manuel; Boulanger, Pierre; Jaremko, Jacob L.; Major, Paul W.

2017-01-01

Purpose To introduce a new approach to reconstruct a 3D model of the TMJ using magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) registered images, and to evaluate the intra-examiner reproducibility values of reconstructing the 3D models of the TMJ. Methods MRI and CBCT images of five patients (10 TMJs) were obtained. Multiple MRIs and CBCT images were registered using a mutual information based algorithm. The articular disc, condylar head and glenoid fossa were segmented at two different occasions, at least one-week apart, by one investigator, and 3D models were reconstructed. Differences between the segmentation at two occasions were automatically measured using the surface contours (Average Perpendicular Distance) and the volume overlap (Dice Similarity Index) of the 3D models. Descriptive analysis of the changes at 2 occasions, including means and standard deviation (SD) were reported to describe the intra-examiner reproducibility. Results The automatic segmentation of the condyle revealed maximum distance change of 1.9±0.93 mm, similarity index of 98% and root mean squared distance of 0.1±0.08 mm, and the glenoid fossa revealed maximum distance change of 2±0.52 mm, similarity index of 96% and root mean squared distance of 0.2±0.04 mm. The manual segmentation of the articular disc revealed maximum distance change of 3.6±0.32 mm, similarity index of 80% and root mean squared distance of 0.3±0.1 mm. Conclusion The MRI-CBCT registration provides a reliable tool to reconstruct 3D models of the TMJ’s soft and hard tissues, allows quantification of the articular disc morphology and position changes with associated differences of the condylar head and glenoid fossa, and facilitates measuring tissue changes over time. PMID:28095486

Three-Dimensional Assessment of Temporomandibular Joint Using MRI-CBCT Image Registration.

PubMed

Al-Saleh, Mohammed A Q; Punithakumar, Kumaradevan; Lagravere, Manuel; Boulanger, Pierre; Jaremko, Jacob L; Major, Paul W

2017-01-01

To introduce a new approach to reconstruct a 3D model of the TMJ using magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) registered images, and to evaluate the intra-examiner reproducibility values of reconstructing the 3D models of the TMJ. MRI and CBCT images of five patients (10 TMJs) were obtained. Multiple MRIs and CBCT images were registered using a mutual information based algorithm. The articular disc, condylar head and glenoid fossa were segmented at two different occasions, at least one-week apart, by one investigator, and 3D models were reconstructed. Differences between the segmentation at two occasions were automatically measured using the surface contours (Average Perpendicular Distance) and the volume overlap (Dice Similarity Index) of the 3D models. Descriptive analysis of the changes at 2 occasions, including means and standard deviation (SD) were reported to describe the intra-examiner reproducibility. The automatic segmentation of the condyle revealed maximum distance change of 1.9±0.93 mm, similarity index of 98% and root mean squared distance of 0.1±0.08 mm, and the glenoid fossa revealed maximum distance change of 2±0.52 mm, similarity index of 96% and root mean squared distance of 0.2±0.04 mm. The manual segmentation of the articular disc revealed maximum distance change of 3.6±0.32 mm, similarity index of 80% and root mean squared distance of 0.3±0.1 mm. The MRI-CBCT registration provides a reliable tool to reconstruct 3D models of the TMJ's soft and hard tissues, allows quantification of the articular disc morphology and position changes with associated differences of the condylar head and glenoid fossa, and facilitates measuring tissue changes over time.

Full-Body Musculoskeletal Model for Muscle-Driven Simulation of Human Gait.

PubMed

Rajagopal, Apoorva; Dembia, Christopher L; DeMers, Matthew S; Delp, Denny D; Hicks, Jennifer L; Delp, Scott L

2016-10-01

Musculoskeletal models provide a non-invasive means to study human movement and predict the effects of interventions on gait. Our goal was to create an open-source 3-D musculoskeletal model with high-fidelity representations of the lower limb musculature of healthy young individuals that can be used to generate accurate simulations of gait. Our model includes bony geometry for the full body, 37 degrees of freedom to define joint kinematics, Hill-type models of 80 muscle-tendon units actuating the lower limbs, and 17 ideal torque actuators driving the upper body. The model's musculotendon parameters are derived from previous anatomical measurements of 21 cadaver specimens and magnetic resonance images of 24 young healthy subjects. We tested the model by evaluating its computational time and accuracy of simulations of healthy walking and running. Generating muscle-driven simulations of normal walking and running took approximately 10 minutes on a typical desktop computer. The differences between our muscle-generated and inverse dynamics joint moments were within 3% (RMSE) of the peak inverse dynamics joint moments in both walking and running, and our simulated muscle activity showed qualitative agreement with salient features from experimental electromyography data. These results suggest that our model is suitable for generating muscle-driven simulations of healthy gait. We encourage other researchers to further validate and apply the model to study other motions of the lower extremity. The model is implemented in the open-source software platform OpenSim. The model and data used to create and test the simulations are freely available at https://simtk.org/home/full_body/, allowing others to reproduce these results and create their own simulations.

An Integrative Wave Model for the Marginal Ice Zone Based on a Rheological Parameterization

DTIC Science & Technology

2015-09-30

2015) Characterizing the behavior of gravity wave propagation into a floating or submerged viscous layer , 2015 AGU Joint Assembly Meeting, May 3–7...are the PI and a PhD student. Task 1: Use an analytical method to determine the propagation of waves through a floating viscoelastic mat for a wide...and Ben Holt. 2 Task 3: Assemble all existing laboratory and field data of wave propagation in ice covers. Task 4: Determine if all existing

Joint PET-MR respiratory motion models for clinical PET motion correction

NASA Astrophysics Data System (ADS)

Manber, Richard; Thielemans, Kris; Hutton, Brian F.; Wan, Simon; McClelland, Jamie; Barnes, Anna; Arridge, Simon; Ourselin, Sébastien; Atkinson, David

2016-09-01

Patient motion due to respiration can lead to artefacts and blurring in positron emission tomography (PET) images, in addition to quantification errors. The integration of PET with magnetic resonance (MR) imaging in PET-MR scanners provides complementary clinical information, and allows the use of high spatial resolution and high contrast MR images to monitor and correct motion-corrupted PET data. In this paper we build on previous work to form a methodology for respiratory motion correction of PET data, and show it can improve PET image quality whilst having minimal impact on clinical PET-MR protocols. We introduce a joint PET-MR motion model, using only 1 min per PET bed position of simultaneously acquired PET and MR data to provide a respiratory motion correspondence model that captures inter-cycle and intra-cycle breathing variations. In the model setup, 2D multi-slice MR provides the dynamic imaging component, and PET data, via low spatial resolution framing and principal component analysis, provides the model surrogate. We evaluate different motion models (1D and 2D linear, and 1D and 2D polynomial) by computing model-fit and model-prediction errors on dynamic MR images on a data set of 45 patients. Finally we apply the motion model methodology to 5 clinical PET-MR oncology patient datasets. Qualitative PET reconstruction improvements and artefact reduction are assessed with visual analysis, and quantitative improvements are calculated using standardised uptake value (SUVpeak and SUVmax) changes in avid lesions. We demonstrate the capability of a joint PET-MR motion model to predict respiratory motion by showing significantly improved image quality of PET data acquired before the motion model data. The method can be used to incorporate motion into the reconstruction of any length of PET acquisition, with only 1 min of extra scan time, and with no external hardware required.

Groundwater contamination in the Roorkee area, India: 2D joint inversion of radiomagnetotelluric and direct current resistivity data

NASA Astrophysics Data System (ADS)

Yogeshwar, P.; Tezkan, B.; Israil, M.; Candansayar, M. E.

2012-01-01

The impact of sewage irrigation and groundwater contamination were investigated near Roorkee in north India using the Direct Current Resistivity (DCR) method and the Radiomagnetotelluric (RMT) method. Intensive field measurements were carried out in the vicinity of a waste disposal site, which was extensively irrigated with sewage water. For comparison a profile was investigated on a reference site, where no contamination was expected. In addition to conventional 1D and 2D inversion, the measured data sets were interpreted using a 2D joint inversion algorithm. The inversion results from the data obtained from the sewage irrigated site indicate a decrease of resistivity up to 75% in comparison with the reference site. The depth range from 5 to 15 m is identified as a shallow unconfined aquifer and the decreased resistivities are ascribed as the influence of contamination. Furthermore, a systematic increase in the resistivities of the shallow unconfined aquifer is detected as we move away from the waste disposal site. The advantages of both, the DCR and RMT methods, are quantitatively integrated by the 2D joint inversion of both data sets and lead to a joint model, which explains both data sets.

New applications of a model of electromechanical impedance for SHM

NASA Astrophysics Data System (ADS)

Pavelko, Vitalijs

2014-03-01

The paper focuses on the further development of the model of the electromechanical impedance (EMI) of the piezoceramics transducer (PZT) and its application for aircraft structural health monitoring (SHM). There was obtained an expression of the electromechanical impedance common to any dimension of models (1D, 2D, 3D), and directly independent from imposed constraints. Determination of the dynamic response of the system "host structure - PZT", which is crucial for the practical application supposes the use of modal analysis. This allows to get a general tool to determine EMI regardless of the specific features of a particular application. Earlier there was considered the technology of separate determination of the dynamic response for the PZT and the structural element". Here another version that involves the joint modal analysis of the entire system "host structure - PZT" is presented. As a result, the dynamic response is obtained in the form of modal decomposition of transducer mechanical strains. The use of models for the free and constrained transducer, analysis of the impact of the adhesive layer to the EMI is demonstrated. In all cases there was analyzed the influence of the dimension of the model (2D and 3D). The validity of the model is confirmed by experimental studies. Correlation between the fatigue crack length in a thin-walled Al plate and EMI of embedded PZT was simulated and compared with test result.

Quality of life in older individuals with joint contractures in geriatric care settings.

PubMed

Heise, Marco; Müller, Martin; Fischer, Uli; Grill, Eva

2016-09-01

The purpose of this study was to analyze the association between functioning and disability and quality of life (QoL) in older individuals with joint contractures in the geriatric care setting. More specifically, this study aimed to identify determinants of QoL out of a defined set of contracture-related categories of the International Classification of Functioning, Disability and Health (ICF). Participants for this multicenter cross-sectional survey were recruited from acute geriatric rehabilitation hospitals, nursing homes, and community nursing facilities in Germany between February and October 2013. QoL was assessed using the validated German version of the EQ-5D index score and the EQ-5D visual analog scale (VAS). Manual and automatic variable selection methods were used to identify the most relevant variables out of 125 contracture-related ICF categories. A total of 241 eligible participants (34.9 % male, mean age 80.1 years) were included. The final models contained 14 ICF categories as predictors of the EQ-5D index score and 15 categories as predictors of the EQ-5D VAS. The statistically significant ICF categories from both models were 'muscle power functions (b730),' 'memory functions (b144),' 'taking care of plants (d6505),' 'recreation and leisure (d920),' 'religion and spirituality (d930),' 'drugs (e1101),' and 'products and technology for personal use in daily living (e115).' We identified the most relevant ICF categories for older individuals with joint contractures and their health-related quality of life. These items describe potential determinants of QoL which may provide the basis for future health interventions aiming to improve QoL for the patients with joint contractures.

Developing Regionalized Models of Lithospheric Thickness and Velocity Structure Across Eurasia and the Middle East from Jointly Inverting P-Wave and S-Wave Receiver Functions with Rayleigh Wave Group and Phase Velocities

DTIC Science & Technology

2010-09-01

lithospheric velocity structure for a wide variety of tectonic regions throughout Eurasia and the Middle East. We expect the regionalized models will improve...constructed by combining the 1D joint inversion models within each tectonic region and validated through regional waveform modeling. The velocity models thus...important differences in lithospheric structure between the cratonic regions of Eastern Europe and the tectonic regions of Western Europe and the

The effect of sacroiliac joint mobilization on pelvic deformation and the static balance ability of female university students with si joint dysfunction.

PubMed

Son, Jeong-Hyun; Park, Gi Duck; Park, Hoo Sung

2014-06-01

[Purpose] The present study aimed to determine the effect of an 8-week program of joint mobilization on changes in pelvic obliquity and pain level in seventeen female university students aged in their 20's with sacroiliac joint dysfunction by dividing them into two groups: a joint mobilization group (MWM) and a control group. [Subjects] Seventeen subjects were selected from female university students aged in their 20's attending N University in Cheon-An City, Korea, The subjects had sacroiliac joint syndrome, but experienced no problems with daily living and had no previous experience of joint mobilization exercise. The subjects were randomly assigned to a joint mobilization group of eight and a control group of nine who performed joint mobilization exercise. [Methods] Body fat and lean body mass were measured using InBody 7.0 (Biospace, Korea). The Direct Segmental Multi-frequency Bioelectrical Impedance Analysis Method (DSM-BIA) was used for body composition measurement. A pressure footstool (Pedoscan, DIERS, Germany) and a trunk measurement system (Formetric 4D, DIERS, Germany), a 3D image processing apparatus with high resolution for vertebrae, were used to measure 3D trunk images of the vertebrae and pelvis obliquity, as well as static balance ability. [Result] The MWM group showed a significantly better Balance than the control group. In addition, the results of the left/right and the front/rear balance abilities were significantly better than those of the control group. [Conclusion] This study proved that a combination of mobilization with movement and functional training was effective in reducing pelvis malposition and pain, and improving static stability control.

Comparison of fatigue crack growth of riveted and bonded aircraft lap joints made of Aluminium alloy 2024-T3 substrates - A numerical study

NASA Astrophysics Data System (ADS)

Pitta, S.; Rojas, J. I.; Crespo, D.

2017-05-01

Aircraft lap joints play an important role in minimizing the operational cost of airlines. Hence, airlines pay more attention to these technologies to improve efficiency. Namely, a major time consuming and costly process is maintenance of aircraft between the flights, for instance, to detect early formation of cracks, monitoring crack growth, and fixing the corresponding parts with joints, if necessary. This work is focused on the study of repairs of cracked aluminium alloy (AA) 2024-T3 plates to regain their original strength; particularly, cracked AA 2024-T3 substrate plates repaired with doublers of AA 2024-T3 with two configurations (riveted and with adhesive bonding) are analysed. The fatigue life of the substrate plates with cracks of 1, 2, 5, 10 and 12.7mm is computed using Fracture Analysis 3D (FRANC3D) tool. The stress intensity factors for the repaired AA 2024-T3 plates are computed for different crack lengths and compared using commercial FEA tool ABAQUS. The results for the bonded repairs showed significantly lower stress intensity factors compared with the riveted repairs. This improves the overall fatigue life of the bonded joint.

Effects of Low-Intensity Pulsed Ultrasound for Preventing Joint Stiffness in Immobilized Knee Model in Rats.

PubMed

Itaya, Nobuyuki; Yabe, Yutake; Hagiwara, Yoshihiro; Kanazawa, Kenji; Koide, Masashi; Sekiguchi, Takuya; Yoshida, Shinichirou; Sogi, Yasuhito; Yano, Toshihisa; Tsuchiya, Masahiro; Saijo, Yoshihumi; Itoi, Eiji

2018-06-01

The purpose of this study was to examine the effect of low-intensity pulsed ultrasound (LIPUS) in preventing joint stiffness. Unilateral knee joints were immobilized in two groups of rats (n = 6/period/group). Under general anesthesia, the immobilized knee joints were exposed to LIPUS for 20 min/d, 5 d/wk, using an existing LIPUS device (LIPUS group, 1.5-MHz frequency, 1.0-kHz repetition cycle, 200-µs burst width and 30-mW/cm 2 power output) until endpoints (2, 4 or 6 wk). In the control group, general anesthesia alone was administered in the same manner as in the other group. The variables compared between the groups included joint angles; histologic, histomorphometric and immunohistochemical analyses; quantitative reverse transcription polymerase chain reactions; and tissue elasticity. LIPUS had a preventive effect on joint stiffness, resulting in decreased adhesion, fibrosis and inflammation and hypoxic response after joint immobilization. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Mechanical properties of the avian acrocoracohumeral ligament and its role in shoulder stabilization in flight.

PubMed

Baier, David Bradley

2012-02-01

Control of movement in the avian shoulder joint is fundamental to understanding the avian wingstroke. The acrocoracohumeral ligament (AHL) is thought to play a key role in stabilizing the glenoid and balancing the pectoralis in gliding flight. If the AHL has to be taut to balance the pectoralis, then it must constrain glenohumeral motion during flapping flight as well. However, birds vary wing kinematics depending on flight speed and behavior. How can a passive ligament accommodate such varying joint movements? Herein, mechanical testing and 3-D modeling are used to link the mechanical properties and morphology of the AHL to its functional role during flapping flight. The bone-ligament-bone complex of the pigeon (Columba livia) fails at a tensile loading of 141 ± 18 N (± s .D., n = 10) or 39 times body weight, which corresponds to a failure stress of 51 MPa, well above expected loads during flight. Simulated AHL length changes, comparisons to glenohumeral kinematics from the literature, and manipulations of partially dissected pigeon specimens all support the hypothesis that the AHL remains taut through downstroke and most of upstroke while becoming slack during the downstroke/upstroke transition. The digital AHL model provides a mechanism for explaining how the AHL can stabilize the shoulder joint under a broad array of humeral paths by constraining the coordination of glenohumeral degrees of freedom. © 2011 WILEY PERIODICALS, INC.

Template-based automatic extraction of the joint space of foot bones from CT scan

NASA Astrophysics Data System (ADS)

Park, Eunbi; Kim, Taeho; Park, Jinah

2016-03-01

Clean bone segmentation is critical in studying the joint anatomy for measuring the spacing between the bones. However, separation of the coupled bones in CT images is sometimes difficult due to ambiguous gray values coming from the noise and the heterogeneity of bone materials as well as narrowing of the joint space. For fine reconstruction of the individual local boundaries, manual operation is a common practice where the segmentation remains to be a bottleneck. In this paper, we present an automatic method for extracting the joint space by applying graph cut on Markov random field model to the region of interest (ROI) which is identified by a template of 3D bone structures. The template includes encoded articular surface which identifies the tight region of the high-intensity bone boundaries together with the fuzzy joint area of interest. The localized shape information from the template model within the ROI effectively separates the bones nearby. By narrowing the ROI down to the region including two types of tissue, the object extraction problem was reduced to binary segmentation and solved via graph cut. Based on the shape of a joint space marked by the template, the hard constraint was set by the initial seeds which were automatically generated from thresholding and morphological operations. The performance and the robustness of the proposed method are evaluated on 12 volumes of ankle CT data, where each volume includes a set of 4 tarsal bones (calcaneus, talus, navicular and cuboid).

Stress analysis of the space telescope focal plane structure joint

NASA Technical Reports Server (NTRS)

Foster, W. A., Jr.; Shoemaker, W. L.

1985-01-01

Two major efforts were begun concerning the Space Telescope focal plane structure joint. The 3-D solid finite element modeling of the bipod flexure plate was carried out. Conceptual models were developed for the load transfer through the three major bolts to the flexure plate. The flexure plate drawings were reconstructed using DADAM for the purpose of developing a file from which the coordinates of any point on the flexure plate could be determined and also to locate the attachment points of the various components which connect with the flexure plate. For modeling convenience the CADAM drawing of the flexure plate has been divided into several regions which will be subdivided into finite elements using MSGMESH, which is a finite element mesh generator available with MSC/NASTRAN. In addition to the CADAM work on the flexure plate, an effort was also begun to develop computer aided drawings of the peripheral beam which will be used to assist in modeling the connection between it and the flexure plate.

A feasibility study of hand kinematics for EVA analysis using magnetic resonance imaging

NASA Technical Reports Server (NTRS)

Dickenson, Reuben D.; Lorenz, Christine H.; Peterson, Steven W.; Strauss, Alvin M.; Main, John A.

1992-01-01

A new method for analyzing the kinematics of joint motion using magnetic resonance imaging (MRI) is described. The reconstruction of the metacarpalphalangeal joint of the left index finger into a 3D graphic display is shown. From the reconstructed volumetric images, measurements of the angles of movement of the applicable bones are obtained and processed by analyzing the screw motion of the joint. Landmark positions are chosen at distinctive locations of the joint at fixed image threshold intensity levels to ensure repeatability. The primarily 2D planar motion of this joint is then studied using a method of constructing coordinate systems using three or more points. A transformation matrix based on a world coordinate system describes the location and orientation of the local target coordinate system. The findings show the applicability of MRI to joint kinematics for gaining further knowledge of the hand-glove design for EVA.

In vivo recruitment patterns in the anterior oblique and dorsoradial ligaments of the first carpometacarpal joint

PubMed Central

Halilaj, Eni; Rainbow, Michael J.; Moore, Douglas C.; Laidlaw, David H.; Weiss, Arnold-Peter C.; Ladd, Amy L.; Crisco, Joseph J.

2015-01-01

The anterior oblique ligament (AOL) and the dorsoradial ligament (DRL) are both regarded as mechanical stabilizers of the thumb carpometacarpal (CMC) joint, which in older women is often affected by osteoarthritis. Inferences on the potential relationship of these ligaments to joint pathomechanics are based on clinical experience and studies of cadaveric tissue, but their function has been studied sparsely in vivo. The purpose of this study was to gain insight into the functions of the AOL and DRL using in vivo joint kinematic data. The thumbs of 44 healthy subjects were imaged with a clinical computed tomography scanner in functional-task and thumb range-of-motion positions. The origins and insertion sites of the AOL and the DRL were identified on the 3D bone models and each ligament was modeled as a set of three fibers whose lengths were the minimum distances between insertion sites. Ligament recruitment, which represented ligament length as a percentage of the maximum length across the scanned positions, was computed for each position and related to joint posture. Mean AOL recruitment was lower than 91% across the CMC range of motion, whereas mean DRL recruitment was generally higher than 91% in abduction and flexion. Under the assumption that ligaments do not strain by more than 10% physiologically, our findings of mean ligament recruitments across the CMC range of motion indicate that the AOL is likely slack during most physiological positions, whereas the DRL may be taut and therefore support the joint in positions of CMC joint abduction and flexion. PMID:25964211

2D joint inversion of CSAMT and magnetic data based on cross-gradient theory

NASA Astrophysics Data System (ADS)

Wang, Kun-Peng; Tan, Han-Dong; Wang, Tao

2017-06-01

A two-dimensional forward and backward algorithm for the controlled-source audio-frequency magnetotelluric (CSAMT) method is developed to invert data in the entire region (near, transition, and far) and deal with the effects of artificial sources. First, a regularization factor is introduced in the 2D magnetic inversion, and the magnetic susceptibility is updated in logarithmic form so that the inversion magnetic susceptibility is always positive. Second, the joint inversion of the CSAMT and magnetic methods is completed with the introduction of the cross gradient. By searching for the weight of the cross-gradient term in the objective function, the mutual influence between two different physical properties at different locations are avoided. Model tests show that the joint inversion based on cross-gradient theory offers better results than the single-method inversion. The 2D forward and inverse algorithm for CSAMT with source can effectively deal with artificial sources and ensures the reliability of the final joint inversion algorithm.

Advanced Methods for Aircraft Engine Thrust and Noise Benefits: Nozzle-Inlet Flow Analysis

NASA Technical Reports Server (NTRS)

Gilinsky, Mikhail; Morgan, Morris H.; Povitsky, Alex; Schkolnikov, Natalia; Njoroge, Norman; Coston, Calvin; Blankson, Isaiah M.

2001-01-01

The Fluid Mechanics and Acoustics Laboratory at Hampton University (HU/FM&AL) jointly with the NASA Glenn Research Center has conducted four connected subprojects under the reporting project. Basically, the HU/FM&AL Team has been involved in joint research with the purpose of theoretical explanation of experimental facts and creation of accurate numerical simulation techniques and prediction theory for solution of current problems in propulsion systems of interest to the NAVY and NASA agencies. This work is also supported by joint research between the NASA GRC and the Institute of Mechanics at Moscow State University (IM/MSU) in Russia under a CRDF grant. The research is focused on a wide regime of problems in the propulsion field as well as in experimental testing and theoretical and numerical simulation analyses for advanced aircraft and rocket engines. The FM&AL Team uses analytical methods, numerical simulations and possible experimental tests at the Hampton University campus. The fundamental idea uniting these subprojects is to use nontraditional 3D corrugated and composite nozzle and inlet designs and additional methods for exhaust jet noise reduction without essential thrust loss and even with thrust augmentation. These subprojects are: (1) Aeroperformance and acoustics of Bluebell-shaped and Telescope-shaped designs; (2) An analysis of sharp-edged nozzle exit designs for effective fuel injection into the flow stream in air-breathing engines: triangular-round, diamond-round and other nozzles; (3) Measurement technique improvement for the HU Low Speed Wind Tunnel; a new course in the field of aerodynamics, teaching and training of HU students; experimental tests of Mobius-shaped screws: research and training; (4) Supersonic inlet shape optimization. The main outcomes during this reporting period are: (l) Publications: The AIAA Paper #00-3170 was presented at the 36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 17-19 June, 2000, Huntsville, AL. The AIAA Paper #01-1893 has been accepted for the AIAA/NAL-NASDA-ISAS 10th International Space Planes and Hypersonic Systems and Technologies Conference, 24-27 April 2001, Kyoto, Japan. The AIAA Paper #01 -3204 has been accepted for presentation at the 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, being held on 08-11 July, in Salt Lake City, UT; (2) A U.S. patent #6,082,635 was granted on July 4, 2000; (3) Grants and proposals: The H U/ FM&AL was awarded the NASA grant NAG-3-2495 in October 2000 and the laboratory is a primary U.S. research team in a joint project under the CRDF award granted to the NASA GRC and IM/MSU (Russia) in July 2000; (4) Theory and numerical simulations: Analytical theory, numerical simulation, comparison of theoretical with experimental results, and modification of theoretical approaches, models, grids, etc., have been conducted for several complicated 2D and 3D nozzle and inlet designs using NASA, ICASE, and IM/MSU codes based on full Euler and Navier-Stokes solvers: CFL3D, FLUENT, and GODUNOV, and others; (5) Experimental Tests: (a) A new course: "Advanced Aerodynamics and Aircraft Performance" presented in spring semester, 2001; training and experimental test research using the HU LSWT. (b) Small-scale M6bius-shaped screws were tested in different conditions and their application has shown essential benefits by comparison with traditional designs; (6) Installation in the FM&AL computer system: second software TECPLOT 8.0 for the UNIX SGI workstation and free TECPLOT 7.5 for the PC Dell computer, and 2D and 3D GRIDGEN (version 9) for the UNIX SGI as well as installation of two free NASA codes, 3D MAG and VULCAN; (7) Student Research Activity: Involvement of two undergraduate students as research assistants in the current research project.

Coupling Hydrodynamic and Wave Propagation Codes for Modeling of Seismic Waves recorded at the SPE Test.

NASA Astrophysics Data System (ADS)

Larmat, C. S.; Rougier, E.; Delorey, A.; Steedman, D. W.; Bradley, C. R.

2016-12-01

The goal of the Source Physics Experiment (SPE) is to bring empirical and theoretical advances to the problem of detection and identification of underground nuclear explosions. For this, the SPE program includes a strong modeling effort based on first principles calculations with the challenge to capture both the source and near-source processes and those taking place later in time as seismic waves propagate within complex 3D geologic environments. In this paper, we report on results of modeling that uses hydrodynamic simulation codes (Abaqus and CASH) coupled with a 3D full waveform propagation code, SPECFEM3D. For modeling the near source region, we employ a fully-coupled Euler-Lagrange (CEL) modeling capability with a new continuum-based visco-plastic fracture model for simulation of damage processes, called AZ_Frac. These capabilities produce high-fidelity models of various factors believed to be key in the generation of seismic waves: the explosion dynamics, a weak grout-filled borehole, the surrounding jointed rock, and damage creation and deformations happening around the source and the free surface. SPECFEM3D, based on the Spectral Element Method (SEM) is a direct numerical method for full wave modeling with mathematical accuracy. The coupling interface consists of a series of grid points of the SEM mesh situated inside of the hydrodynamic code's domain. Displacement time series at these points are computed using output data from CASH or Abaqus (by interpolation if needed) and fed into the time marching scheme of SPECFEM3D. We will present validation tests with the Sharpe's model and comparisons of waveforms modeled with Rg waves (2-8Hz) that were recorded up to 2 km for SPE. We especially show effects of the local topography, velocity structure and spallation. Our models predict smaller amplitudes of Rg waves for the first five SPE shots compared to pure elastic models such as Denny &Johnson (1991).

Segment-interaction in sprint start: Analysis of 3D angular velocity and kinetic energy in elite sprinters.

PubMed

Slawinski, J; Bonnefoy, A; Ontanon, G; Leveque, J M; Miller, C; Riquet, A; Chèze, L; Dumas, R

2010-05-28

The aim of the present study was to measure during a sprint start the joint angular velocity and the kinetic energy of the different segments in elite sprinters. This was performed using a 3D kinematic analysis of the whole body. Eight elite sprinters (10.30+/-0.14s 100 m time), equipped with 63 passive reflective markers, realised four maximal 10 m sprints start on an indoor track. An opto-electronic Motion Analysis system consisting of 12 digital cameras (250 Hz) was used to collect the 3D marker trajectories. During the pushing phase on the blocks, the 3D angular velocity vector and its norm were calculated for each joint. The kinetic energy of 16 segments of the lower and upper limbs and of the total body was calculated. The 3D kinematic analysis of the whole body demonstrated that joints such as shoulders, thoracic or hips did not reach their maximal angular velocity with a movement of flexion-extension, but with a combination of flexion-extension, abduction-adduction and internal-external rotation. The maximal kinetic energy of the total body was reached before clearing block (respectively, 537+/-59.3 J vs. 514.9+/-66.0 J; p< or =0.01). These results suggested that a better synchronization between the upper and lower limbs could increase the efficiency of pushing phase on the blocks. Besides, to understand low interindividual variances in the sprint start performance in elite athletes, a 3D complete body kinematic analysis shall be used. Copyright 2010 Elsevier Ltd. All rights reserved.

What is the price for the Duchenne gait pattern in patients with cerebral palsy?

PubMed

Salami, Firooz; Niklasch, Mirjam; Krautwurst, Britta K; Dreher, Thomas; Wolf, Sebastian I

2017-10-01

Duchenne gait is characterized by trunk lean towards the affected stance limb with the pelvis stable or elevated on the swinging limb side during single limb stance phase. We assessed the relationship between hip abduction moments and trunk kinetics in patients with cerebral palsy showing excessive lateral trunk motion. Data of 18 subjects with bilateral spastic cerebral palsy (CP) and 20 aged matched typically developing subjects (TD) were collected retrospectively. Criteria for patient selection were barefoot walking without aid presenting with excessive lateral trunk motion. Subjects had been monitored by conventional 3D gait analysis of the lower extremity including four markers for monitoring trunk motion. Post-hoc, a generic musculoskeletal full body model (OpenSim 3.3) assuming a rigid trunk articulated to the pelvis by a single ball joint was applied for analyzing joint kinematics and kinetics of the lower limb joints including this spine joint. Joint angle ranges of motion, maximum joint moments and powers in the frontal plane as well as mechanical work were calculated and averaged within groups showing prominent differences between groups in all parameters. To the best of our knowledge, this is the first work explicitly looking into the kinetics of Duchenne gait in patients with CP, clinically known as compensation for unloading hip abductor muscles. The results show that excessive lateral trunk motion may indeed be an extremely effective compensation mechanism to unload the hip abductors in single limb stance but for the price of a drastic increase in demand on trunk muscle effort and work. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimized resolved rate control of seven-degree-of-freedom Laboratory Telerobotic Manipulator (LTM) with application to three-dimensional graphics simulation

NASA Technical Reports Server (NTRS)

Barker, L. Keith; Mckinney, William S., Jr.

1989-01-01

The Laboratory Telerobotic Manipulator (LTM) is a seven-degree-of-freedom robot arm. Two of the arms were delivered to Langley Research Center for ground-based research to assess the use of redundant degree-of-freedom robot arms in space operations. Resolved-rate control equations for the LTM are derived. The equations are based on a scheme developed at the Oak Ridge National Laboratory for computing optimized joint angle rates in real time. The optimized joint angle rates actually represent a trade-off, as the hand moves, between small rates (least-squares solution) and those rates which work toward satisfying a specified performance criterion of joint angles. In singularities where the optimization scheme cannot be applied, alternate control equations are devised. The equations developed were evaluated using a real-time computer simulation to control a 3-D graphics model of the LTM.

Ionosphere research with a HF/MF cubesat radio instrument

NASA Astrophysics Data System (ADS)

Kallio, Esa; Aikio, Anita; Alho, Markku; Fontell, Mathias; Harri, Ari-Matti; Kauristie, Kirsti; Kestilä, Antti; Koskimaa, Petri; Mäkelä, Jakke; Mäkelä, Miika; Turunen, Esa; Vanhamäki, Heikki; Verronen, Pekka

2017-04-01

New technology provides new possibilities to study geospace and 3D ionosphere by using spacecraft and computer simulations. A type of nanosatellites, CubeSats, provide a cost effective possibility to provide in-situ measurements in the ionosphere. Moreover, combined CubeSat observations with ground-based observations gives a new view on auroras and associated electromagnetic phenomena. Especially joint and active CubeSat - ground based observation campaigns enable the possibility of studying the 3D structure of the ionosphere. Furthermore using several CubeSats to form satellite constellations enables much higher temporal resolution. At the same time, increasing computation capacity has made it possible to perform simulations where properties of the ionosphere, such as propagation of the electromagnetic waves in the medium frequency, MF (0.3-3 MHz) and high frequency, HF (3-30 MHz), ranges is based on a 3D ionospheric model and on first-principles modelling. Electromagnetic waves at those frequencies are strongly affected by ionospheric electrons and, consequently, those frequencies can be used for studying the plasma. On the other hand, even if the ionosphere originally enables long-range telecommunication at MF and HF frequencies, the frequent occurrence of spatiotemporal variations in the ionosphere disturbs communication channels, especially at high latitudes. Therefore, study of the MF and HF waves in the ionosphere has both a strong science and technology interests. We introduce recently developed simulation models as well as measuring principles and techniques to investigate the arctic ionosphere by a polar orbiting CubeSat whose novel AM radio instrument measures HF and MF waves. The cubesat, which contains also a white light aurora camera, is planned to be launched in late 2017 (http://www.suomi100satelliitti.fi/eng). The new models are (1) a 3D ray tracing model and (2) a 3D full kinetic electromagnetic simulation. We also introduce how combining of the cubesat measurements to ground based measurements provides new research possibilities to study 3D ionosphere.

Near-field non-radial motion generation from underground chemical explosions in jointed granite

NASA Astrophysics Data System (ADS)

Vorobiev, Oleg; Ezzedine, Souheil; Hurley, Ryan

2018-01-01

This paper describes analysis of non-radial ground motion generated by chemical explosions in a jointed rock formation during the Source Physics Experiment (SPE). Such motion makes it difficult to discriminate between various subsurface events such as explosions, implosions (i.e. mine collapse) and earthquakes. We apply 3-D numerical simulations to understand experimental data collected during the SPEs. The joints are modelled explicitly as compliant thin inclusions embedded into the rock mass. Mechanical properties of the rock and the joints as well as the joint spacing and orientation are inferred from experimental test data, and geophysical and geological characterization of the SPE site which is dominantly Climax Stock granitic outcrop. The role of various factors characterizing the joints such as joint spacing, frictional properties, orientation and persistence in generation of non-radial motion is addressed. The joints in granite at the SPE site are oriented in nearly orthogonal directions with two vertical sets dipping at 70-80 degrees with the same strike angle, one vertical set almost orthogonal to the first two and one shallow angle joint set dipping 15 degrees. In this study we establish the relationship between the joint orientation and azimuthal variations in the polarity of the observed shear motion. The majority of the shear motion is generated due to the effects of non-elastic sliding on the joints near the source, where the wave can create significant shear stress to overcome the cohesive forces at the joints. Near the surface the joints are less confined and are subject to sliding when the pressure waves are reflected. In the far field, where the cohesive forces on the joints cannot be overcome, additional shear motion can be generated due to elastic anisotropy of the rock mass given by preferred spatial orientations of compliant joints.

Electrospun Microfiber Scaffolds with Anti-Inflammatory Tributanoylated N-Acetyl-d-Glucosamine Promote Cartilage Regeneration

PubMed Central

Kim, Chaekyu; Shores, Lucas; Guo, Qiongyu; Aly, Ahmed; Jeon, Ok Hee; Kim, Do Hun; Bernstein, Nicholas; Bhattacharya, Rahul; Chae, Jemin Jeremy; Yarema, Kevin J.

2016-01-01

Tissue-engineering strategies offer promising tools for repairing cartilage damage; however, these strategies suffer from limitations under pathological conditions. As a model disease for these types of nonideal systems, the inflammatory environment in an osteoarthritic (OA) joint limits the efficacy of engineered therapeutics by disrupting joint homeostasis and reducing its capacity for regeneration. In this work, we investigated a sugar-based drug candidate, a tributanoylated N-acetyl-d-glucosamine analogue, called 3,4,6-O-Bu3GlcNAc, that is known to reduce nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in osteoarthritis. 3,4,6-O-Bu3GlcNAc not only inhibited NFκB signaling but also exerted chondrogenic and anti-inflammatory effects on chondrocytes isolated from patients with osteoarthritis. 3,4,6-O-Bu3GlcNAc also increased the expression of extracellular matrix proteins and induced cartilage tissue production in three-dimensional in vitro hydrogel culture systems. To translate these chondrogenic and anti-inflammatory properties to tissue regeneration in osteoarthritis, we implanted 3,4,6-O-Bu3GlcNAc-loaded poly(lactic-co-glycolic acid) microfiber scaffolds into rats. The drug-laden scaffolds were biocompatible, and when seeded with human OA chondrocytes, similarly promoted cartilage tissue formation. 3,4,6-O-Bu3GlcNAc combined with the appropriate structural environment could be a promising therapeutic approach for osteoarthritis. PMID:27019285

Bayesian seismic inversion based on rock-physics prior modeling for the joint estimation of acoustic impedance, porosity and lithofacies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Passos de Figueiredo, Leandro, E-mail: leandrop.fgr@gmail.com; Grana, Dario; Santos, Marcio

We propose a Bayesian approach for seismic inversion to estimate acoustic impedance, porosity and lithofacies within the reservoir conditioned to post-stack seismic and well data. The link between elastic and petrophysical properties is given by a joint prior distribution for the logarithm of impedance and porosity, based on a rock-physics model. The well conditioning is performed through a background model obtained by well log interpolation. Two different approaches are presented: in the first approach, the prior is defined by a single Gaussian distribution, whereas in the second approach it is defined by a Gaussian mixture to represent the well datamore » multimodal distribution and link the Gaussian components to different geological lithofacies. The forward model is based on a linearized convolutional model. For the single Gaussian case, we obtain an analytical expression for the posterior distribution, resulting in a fast algorithm to compute the solution of the inverse problem, i.e. the posterior distribution of acoustic impedance and porosity as well as the facies probability given the observed data. For the Gaussian mixture prior, it is not possible to obtain the distributions analytically, hence we propose a Gibbs algorithm to perform the posterior sampling and obtain several reservoir model realizations, allowing an uncertainty analysis of the estimated properties and lithofacies. Both methodologies are applied to a real seismic dataset with three wells to obtain 3D models of acoustic impedance, porosity and lithofacies. The methodologies are validated through a blind well test and compared to a standard Bayesian inversion approach. Using the probability of the reservoir lithofacies, we also compute a 3D isosurface probability model of the main oil reservoir in the studied field.« less

On the analysis of condylar path versus real motion of the temporomandibular joint: application for Sicat Function.

PubMed

Kordaß, Bernd; Ruge, Sebastian

2015-01-01

Analysis of temporomandibular joint (TMJ) function using condylar path tracings is a challenge in functionally oriented dentistry. In most cases, reference points on the skin surface over the TMJ region are defined as "arbitrary", "individual" or "kinematic" condylar hinge axis points, which are displayed as "condylar paths" in motion. To what extent these reference points represent the actual condylar paths in each individual patient is ultimately unclear because the geometric relationship of the actual condyle to the selected reference point is usually unknown. Depending on the location of the point on the condyle and the centers of rotation of mandibular movement, these trajectories can vary greatly during combined rotational and sliding movements (eg, opening and closing movements of the mandible); this represents a grid of points located in the vicinity of the TMJ. To record the actual condylar path as the movement trajectory of a given point (eg, the condylar center), technological solutions are needed with which to link the tracing technology with the appropriate imaging technology capable of scanning the condyle, including the points of interest, and displaying them in real dynamic motion. Sicat Function (Sicat, D-Bonn) is such a solution. Sicat Function links cone beam computed tomography (CBCT) scans (made using the Galileos CBCT scanner; Sirona, Bensheim, Germany) with ultrasound-based, three-dimensional (3D) functional jaw movement recordings of the mandible (made using the JMT+ Jaw Motion Tracker; Sicat, Bonn, Germany). Digital images of the dental arches acquired with the intraoral scanner Cerec system (Sirona) can also be superimposed. This results in the generation of a 3D model of the bony mandible, including the TMJ, which reproduces the 3D real dynamic movement of the condyles simultaneously with that of the condylar paths at defined points (with the condylar centers being a particular point of interest). Sicat Function is an integrated, digital 3D solution for additional instrumental and imaging diagnosis of temporomandibular joint dysfunction (TMD). The primary indication for Sicat Function is persistent, arthrogenic TMD complaints that require additional studies for evaluation of bony structural components of the TMJ.

Medial knee joint contact force in the intact limb during walking in recently ambulatory service members with unilateral limb loss: a cross-sectional study

PubMed Central

Krupenevich, Rebecca L.; Pruziner, Alison L.; Wolf, Erik J.; Schnall, Barri L.

2017-01-01

Background Individuals with unilateral lower limb amputation have a high risk of developing knee osteoarthritis (OA) in their intact limb as they age. This risk may be related to joint loading experienced earlier in life. We hypothesized that loading during walking would be greater in the intact limb of young US military service members with limb loss than in controls with no limb loss. Methods Cross-sectional instrumented gait analysis at self-selected walking speeds with a limb loss group (N = 10, age 27 ± 5 years, 170 ± 36 days since last surgery) including five service members with transtibial limb loss and five with transfemoral limb loss, all walking independently with their first prosthesis for approximately two months. Controls (N = 10, age 30 ± 4 years) were service members with no overt demographical risk factors for knee OA. 3D inverse dynamics modeling was performed to calculate joint moments and medial knee joint contact forces (JCF) were calculated using a reduction-based musculoskeletal modeling method and expressed relative to body weight (BW). Results Peak JCF and maximum JCF loading rate were significantly greater in limb loss (184% BW, 2,469% BW/s) vs. controls (157% BW, 1,985% BW/s), with large effect sizes. Results were robust to probabilistic perturbations to the knee model parameters. Discussion Assuming these data are reflective of joint loading experienced in daily life, they support a “mechanical overloading” hypothesis for the risk of developing knee OA in the intact limb of limb loss subjects. Examination of the evolution of gait mechanics, joint loading, and joint health over time, as well as interventions to reduce load or strengthen the ability of the joint to withstand loads, is warranted. PMID:28168120

High Performance Automatic Character Skinning Based on Projection Distance

NASA Astrophysics Data System (ADS)

Li, Jun; Lin, Feng; Liu, Xiuling; Wang, Hongrui

2018-03-01

Skeleton-driven-deformation methods have been commonly used in the character deformations. The process of painting skin weights for character deformation is a long-winded task requiring manual tweaking. We present a novel method to calculate skinning weights automatically from 3D human geometric model and corresponding skeleton. The method first, groups each mesh vertex of 3D human model to a skeleton bone by the minimum distance from a mesh vertex to each bone. Secondly, calculates each vertex's weights to the adjacent bones by the vertex's projection point distance to the bone joints. Our method's output can not only be applied to any kind of skeleton-driven deformation, but also to motion capture driven (mocap-driven) deformation. Experiments results show that our method not only has strong generality and robustness, but also has high performance.

Combined registration of 3D tibia and femur implant models in 3D magnetic resonance images

NASA Astrophysics Data System (ADS)

Englmeier, Karl-Hans; Siebert, Markus; von Eisenhart-Rothe, Ruediger; Graichen, Heiko

2008-03-01

The most frequent reasons for revision of total knee arthroplasty are loosening and abnormal axial alignment leading to an unphysiological kinematic of the knee implant. To get an idea about the postoperative kinematic of the implant, it is essential to determine the position and orientation of the tibial and femoral prosthesis. Therefore we developed a registration method for fitting 3D CAD-models of knee joint prostheses into an 3D MR image. This rigid registration is the basis for a quantitative analysis of the kinematics of knee implants. Firstly the surface data of the prostheses models are converted into a voxel representation; a recursive algorithm determines all boundary voxels of the original triangular surface data. Secondly an initial preconfiguration of the implants by the user is still necessary for the following step: The user has to perform a rough preconfiguration of both remaining prostheses models, so that the fine matching process gets a reasonable starting point. After that an automated gradient-based fine matching process determines the best absolute position and orientation: This iterative process changes all 6 parameters (3 rotational- and 3 translational parameters) of a model by a minimal amount until a maximum value of the matching function is reached. To examine the spread of the final solutions of the registration, the interobserver variability was measured in a group of testers. This variability, calculated by the relative standard deviation, improved from about 50% (pure manual registration) to 0.5% (rough manual preconfiguration and subsequent fine registration with the automatic fine matching process).

Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

PubMed

Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

2016-01-01

The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study

PubMed Central

Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

2016-01-01

The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a “soft” constraint using a penalty-based method, this elastic joint description challenges the strictness of “hard” constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO. PMID:27314586

Experimental Investigation into the Fatigue Life of Hybrid Joints Under Fully Reversed Flexure Loading

DTIC Science & Technology

2008-06-01

joint classification 3 b. Hot spot-stress approach c. Notch-stress approach * d. Mesh-insensitive approach 2. Fracture mechanics (used for crack... classification approach, which is an adaptation of the nominal stress approach just discussed, with the welded joint fatigue curves as given in Table...used. More detail is provided on the joint classifications , and -- 19 I graphic representations are also included. It is explained that the stress

Elastic robot control - Nonlinear inversion and linear stabilization

NASA Technical Reports Server (NTRS)

Singh, S. N.; Schy, A. A.

1986-01-01

An approach to the control of elastic robot systems for space applications using inversion, servocompensation, and feedback stabilization is presented. For simplicity, a robot arm (PUMA type) with three rotational joints is considered. The third link is assumed to be elastic. Using an inversion algorithm, a nonlinear decoupling control law u(d) is derived such that in the closed-loop system independent control of joint angles by the three joint torquers is accomplished. For the stabilization of elastic oscillations, a linear feedback torquer control law u(s) is obtained applying linear quadratic optimization to the linearized arm model augmented with a servocompensator about the terminal state. Simulation results show that in spite of uncertainties in the payload and vehicle angular velocity, good joint angle control and damping of elastic oscillations are obtained with the torquer control law u = u(d) + u(s).

Lithostratigraphic interpretation from joint analysis of seismic tomography and magnetotelluric resistivity models using self-organizing map techniques

NASA Astrophysics Data System (ADS)

Bauer, K.; Muñoz, G.; Moeck, I.

2012-12-01

The combined interpretation of different models as derived from seismic tomography and magnetotelluric (MT) inversion represents a more efficient approach to determine the lithology of the subsurface compared with the separate treatment of each discipline. Such models can be developed independently or by application of joint inversion strategies. After the step of model generation using different geophysical methodologies, a joint interpretation work flow includes the following steps: (1) adjustment of a joint earth model based on the adapted, identical model geometry for the different methods, (2) classification of the model components (e.g. model blocks described by a set of geophysical parameters), and (3) re-mapping of the classified rock types to visualise their distribution within the earth model, and petrophysical characterization and interpretation. One possible approach for the classification of multi-parameter models is based on statistical pattern recognition, where different models are combined and translated into probability density functions. Classes of rock types are identified in these methods as isolated clusters with high probability density function values. Such techniques are well-established for the analysis of two-parameter models. Alternatively we apply self-organizing map (SOM) techniques, which have no limitations in the number of parameters to be analysed in the joint interpretation. Our SOM work flow includes (1) generation of a joint earth model described by so-called data vectors, (2) unsupervised learning or training, (3) analysis of the feature map by adopting image processing techniques, and (4) application of the knowledge to derive a lithological model which is based on the different geophysical parameters. We show the usage of the SOM work flow for a synthetic and a real data case study. Both tests rely on three geophysical properties: P velocity and vertical velocity gradient from seismic tomography, and electrical resistivity from MT inversion. The synthetic data are used as a benchmark test to demonstrate the performance of the SOM method. The real data were collected along a 40 km profile across parts of the NE German basin. The lithostratigraphic model from the joint SOM interpretation consists of eight litho-types and covers Cenozoic, Mesozoic and Paleozoic sediments down to 5 km depth. There is a remarkable agreement between the SOM based model and regional marker horizons interpolated from surrounding 2D industrial seismic data. The most interesting results include (1) distinct properties of the Jurassic (low P velocity gradients, low resistivities) interpreted as the signature of shaly clastics, and (2) a pattern within the Upper Permian Zechstein with decreased resistivities and increased P velocities within the salt depressions on the one hand, and increased resistivities and decreased P velocities in the salt pillows on the other hand. In our interpretation this pattern is related with flow of less dense salt matrix components into the pillows and remaining brittle evaporites within the depressions.

Investigating source processes of isotropic events

NASA Astrophysics Data System (ADS)

Chiang, Andrea

This dissertation demonstrates the utility of the complete waveform regional moment tensor inversion for nuclear event discrimination. I explore the source processes and associated uncertainties for explosions and earthquakes under the effects of limited station coverage, compound seismic sources, assumptions in velocity models and the corresponding Green's functions, and the effects of shallow source depth and free-surface conditions. The motivation to develop better techniques to obtain reliable source mechanism and assess uncertainties is not limited to nuclear monitoring, but they also provide quantitative information about the characteristics of seismic hazards, local and regional tectonics and in-situ stress fields of the region . This dissertation begins with the analysis of three sparsely recorded events: the 14 September 1988 US-Soviet Joint Verification Experiment (JVE) nuclear test at the Semipalatinsk test site in Eastern Kazakhstan, and two nuclear explosions at the Chinese Lop Nor test site. We utilize a regional distance seismic waveform method fitting long-period, complete, three-component waveforms jointly with first-motion observations from regional stations and teleseismic arrays. The combination of long period waveforms and first motion observations provides unique discrimination of these sparsely recorded events in the context of the Hudson et al. (1989) source-type diagram. We examine the effects of the free surface on the moment tensor via synthetic testing, and apply the moment tensor based discrimination method to well-recorded chemical explosions. These shallow chemical explosions represent rather severe source-station geometry in terms of the vanishing traction issues. We show that the combined waveform and first motion method enables the unique discrimination of these events, even though the data include unmodeled single force components resulting from the collapse and blowout of the quarry face immediately following the initial explosion. In contrast, recovering the announced explosive yield using seismic moment estimates from moment tensor inversion remains challenging but we can begin to put error bounds on our moment estimates using the NSS technique. The estimation of seismic source parameters is dependent upon having a well-calibrated velocity model to compute the Green's functions for the inverse problem. Ideally, seismic velocity models are calibrated through broadband waveform modeling, however in regions of low seismicity velocity models derived from body or surface wave tomography may be employed. Whether a velocity model is 1D or 3D, or based on broadband seismic waveform modeling or the various tomographic techniques, the uncertainty in the velocity model can be the greatest source of error in moment tensor inversion. These errors have not been fully investigated for the nuclear discrimination problem. To study the effects of unmodeled structures on the moment tensor inversion, we set up a synthetic experiment where we produce synthetic seismograms for a 3D model (Moschetti et al., 2010) and invert these data using Green's functions computed with a 1D velocity mode (Song et al., 1996) to evaluate the recoverability of input solutions, paying particular attention to biases in the isotropic component. The synthetic experiment results indicate that the 1D model assumption is valid for moment tensor inversions at periods as short as 10 seconds for the 1D western U.S. model (Song et al., 1996). The correct earthquake mechanisms and source depth are recovered with statistically insignificant isotropic components as determined by the F-test. Shallow explosions are biased by the theoretical ISO-CLVD tradeoff but the tectonic release component remains low, and the tradeoff can be eliminated with constraints from P wave first motion. Path-calibration to the 1D model can reduce non-double-couple components in earthquakes, non-isotropic components in explosions and composite sources and improve the fit to the data. When we apply the 3D model to real data, at long periods (20-50 seconds), we see good agreement in the solutions between the 1D and 3D models and slight improvement in waveform fits when using the 3D velocity model Green's functions. (Abstract shortened by ProQuest.).

Evaluation Transportability Testing of the Joint Modular Intermodal Platform (JMIP) Unit #4 TP-94-01, Revision 2, June 2004, Transportability Testing Procedures

DTIC Science & Technology

2007-07-01

Weight: 19,340 lbs 3-1 5. Semitrailer, flatbed , breakbulk/container transporter, 34 ton Model #: M872A1 Manufactured by Heller Truck Body Corporation...REQD). LAMINATE TO BEARING PIECE W/6-10d NAILS EVENLY SPACED. SIDE STRAPPING BOARD ASSEMBLY (4 RECD) EPAGE 5 NOTE: PRODUCE EQUAL QUANTITES OF ASSEMBLY...A AND ASSEMBLY B. EACH JMIP LOAD REQUIRES iWO OF EACH (4 TOTAL). STEEL EDGE PROTECTORS (2 REQD). LAMINATE TO BEARING AND CORNER PIECES W/4-6d NALS AND

Dynamic motion planning of 3D human locomotion using gradient-based optimization.

PubMed

Kim, Hyung Joo; Wang, Qian; Rahmatalla, Salam; Swan, Colby C; Arora, Jasbir S; Abdel-Malek, Karim; Assouline, Jose G

2008-06-01

Since humans can walk with an infinite variety of postures and limb movements, there is no unique solution to the modeling problem to predict human gait motions. Accordingly, we test herein the hypothesis that the redundancy of human walking mechanisms makes solving for human joint profiles and force time histories an indeterminate problem best solved by inverse dynamics and optimization methods. A new optimization-based human-modeling framework is thus described for predicting three-dimensional human gait motions on level and inclined planes. The basic unknowns in the framework are the joint motion time histories of a 25-degree-of-freedom human model and its six global degrees of freedom. The joint motion histories are calculated by minimizing an objective function such as deviation of the trunk from upright posture that relates to the human model's performance. A variety of important constraints are imposed on the optimization problem, including (1) satisfaction of dynamic equilibrium equations by requiring the model's zero moment point (ZMP) to lie within the instantaneous geometrical base of support, (2) foot collision avoidance, (3) limits on ground-foot friction, and (4) vanishing yawing moment. Analytical forms of objective and constraint functions are presented and discussed for the proposed human-modeling framework in which the resulting optimization problems are solved using gradient-based mathematical programming techniques. When the framework is applied to the modeling of bipedal locomotion on level and inclined planes, acyclic human walking motions that are smooth and realistic as opposed to less natural robotic motions are obtained. The aspects of the modeling framework requiring further investigation and refinement, as well as potential applications of the framework in biomechanics, are discussed.

17 CFR 270.17d-3 - Exemption relating to certain joint enterprises or arrangements concerning payment for...

Code of Federal Regulations, 2010 CFR

2010-04-01

... management investment company. 270.17d-3 Section 270.17d-3 Commodity and Securities Exchanges SECURITIES AND... registered open-end management investment company. An affiliated person of, or principal underwriter for, a registered open-end management investment company and an affiliated person of such a person or principal...

Advance Warning and Risk Evaluator (AWARE): Background, Preliminary Findings, and Way Ahead

DTIC Science & Technology

2013-02-12

in press). Guilt, shame , and suicidal ideation in a military outpatient clinical sample. Depression and Anxiety. Chairman of the Joint Chiefs of...Instruction 1308.3., DoD Physical Fitness and Body Fat Programs Procedures, November 5, 2002. DoD Instruction 1325.06., Handling Dissident and...press). Guilt, shame , and suicidal ideation in a military outpatient clinical sample. Depression and Anxiety. Chairman of the Joint Chiefs of Staff

Active and passive electrical and seismic time-lapse monitoring of earthen embankments

NASA Astrophysics Data System (ADS)

Rittgers, Justin Bradley

In this dissertation, I present research involving the application of active and passive geophysical data collection, data assimilation, and inverse modeling for the purpose of earthen embankment infrastructure assessment. Throughout the dissertation, I identify several data characteristics, and several challenges intrinsic to characterization and imaging of earthen embankments and anomalous seepage phenomena, from both a static and time-lapse geophysical monitoring perspective. I begin with the presentation of a field study conducted on a seeping earthen dam, involving static and independent inversions of active tomography data sets, and self-potential modeling of fluid flow within a confined aquifer. Additionally, I present results of active and passive time-lapse geophysical monitoring conducted during two meso-scale laboratory experiments involving the failure and self-healing of embankment filter materials via induced vertical cracking. Identified data signatures and trends, as well as 4D inversion results, are discussed as an underlying motivation for conducting subsequent research. Next, I present a new 4D acoustic emissions source localization algorithm that is applied to passive seismic monitoring data collected during a full-scale embankment failure test. Acoustic emissions localization results are then used to help spatially constrain 4D inversion of collocated self-potential monitoring data. I then turn to time-lapse joint inversion of active tomographic data sets applied to the characterization and monitoring of earthen embankments. Here, I develop a new technique for applying spatiotemporally varying structural joint inversion constraints. The new technique, referred to as Automatic Joint Constraints (AJC), is first demonstrated on a synthetic 2D joint model space, and is then applied to real geophysical monitoring data sets collected during a full-scale earthen embankment piping-failure test. Finally, I discuss some non-technical issues related to earthen embankment failures from a Science, Technology, Engineering, and Policy (STEP) perspective. Here, I discuss how the proclaimed scientific expertise and shifting of responsibility (Responsibilization) by governing entities tasked with operating and maintaining water storage and conveyance infrastructure throughout the United States tends to create barriers for 1) public voice and participation in relevant technical activities and outcomes, 2) meaningful discussions with the public and media during crisis communication, and 3) public perception of risk and the associated resilience of downhill communities.

An adaptive coupling strategy for joint inversions that use petrophysical information as constraints

NASA Astrophysics Data System (ADS)

Heincke, Björn; Jegen, Marion; Moorkamp, Max; Hobbs, Richard W.; Chen, Jin

2017-01-01

Joint inversion strategies for geophysical data have become increasingly popular as they allow for the efficient combination of complementary information from different data sets. The algorithm used for the joint inversion needs to be flexible in its description of the subsurface so as to be able to handle the diverse nature of the data. Hence, joint inversion schemes are needed that 1) adequately balance data from the different methods, 2) have stable convergence behavior, 3) consider the different resolution power of the methods used and 4) link the parameter models in a way that they are suited for a wide range of applications. Here, we combine active source seismic P-wave tomography, gravity and magnetotelluric (MT) data in a petrophysical joint inversion that accounts for these issues. Data from the different methods are inverted separately but are linked through constraints accounting for parameter relationships. An advantage of performing the inversions separately is that no relative weighting between the data sets is required. To avoid perturbing the convergence behavior of the inversions by the coupling, the strengths of the constraints are readjusted at each iteration. The criterion we use to control the adaption of the coupling strengths is based on variations in the objective functions of the individual inversions from one to the next iteration. Adaption of the coupling strengths makes the joint inversion scheme also applicable to subsurface conditions, where assumed relationships are not valid everywhere, because the individual inversions decouple if it is not possible to reach adequately low data misfits for the made assumptions. In addition, the coupling constraints depend on the relative resolutions of the methods, which leads to an improved convergence behavior of the joint inversion. Another benefit of the proposed scheme is that structural information can easily be incorporated in the petrophysical joint inversion (no additional terms are added in the objective functions) by using mutually controlled structural weights for the smoothing constraints. We test our scheme using data generated from a synthetic 2-D sub-basalt model. We observe that the adaption of the coupling strengths makes the convergence of the inversions very robust (data misfits of all methods are close to the target misfits) and that final results are always close to the true models independent of the parameter choices. Finally, the scheme is applied on real data sets from the Faroe-Shetland Basin to image a basaltic sequence and underlying structures. The presence of a borehole and a 3-D reflection seismic survey in this region allows direct comparison and, hence, evaluate the quality of the joint inversion results. The results from joint inversion are more consistent with results from other studies than the ones from the corresponding individual inversions and the shape of the basaltic sequence is better resolved. However, due to the limited resolution of the individual methods used it was not possible to resolve structures underneath the basalt in detail, indicating that additional geophysical information (e.g. CSEM, reflection onsets) needs to be included.

Walking patterns and hip contact forces in patients with hip dysplasia.

PubMed

Skalshøi, Ole; Iversen, Christian Hauskov; Nielsen, Dennis Brandborg; Jacobsen, Julie; Mechlenburg, Inger; Søballe, Kjeld; Sørensen, Henrik

2015-10-01

Several studies have investigated walking characteristics in hip dysplasia patients, but so far none have described all hip rotational degrees of freedom during the whole gait cycle. This descriptive study reports 3D joint angles and torques, and furthermore extends previous studies with muscle and joint contact forces in 32 hip dysplasia patients and 32 matching controls. 3D motion capture data from walking and standing trials were analysed. Hip, knee, ankle and pelvis angles were calculated with inverse kinematics for both standing and walking trials. Hip, knee and ankle torques were calculated with inverse dynamics, while hip muscle and joint contact forces were calculated with static optimisation for the walking trials. No differences were found between the two groups while standing. While walking, patients showed decreased hip extension, increased ankle pronation and increased hip abduction and external rotation torques. Furthermore, hip muscle forces were generally lower and shifted to more posteriorly situated muscles, while the hip joint contact force was lower and directed more superiorly. During walking, patients showed lower and more superiorly directed hip joint contact force, which might alleviate pain from an antero-superiorly degenerated joint. Copyright © 2015 Elsevier B.V. All rights reserved.

Apple App Store as a Business Model Supporting U.S. Navy Requirements

DTIC Science & Technology

2012-04-30

through an annual Broad Agency Announcement, sponsored by the USD(AT&L). Second, we issue an annual internal call for proposals to seek NPS faculty...Ñçê=fåÑçêãÉÇ=`Ü~åÖÉ= -=157 - = Panel 20. Application of an App Store Software Model Within the DoD Thursday, May 17, 2012 1:45 p.m. – 3:15 p.m...Networking: There’s an App for That! Improving Affordability and Accelerating Innovation in Tactical Networking Using the Joint Tactical Radio System

Joint 3D Inversion of ZTEM Airborne and Ground MT Data with Application to Geothermal Exploration

NASA Astrophysics Data System (ADS)

Wannamaker, P. E.; Maris, V.; Kordy, M. A.

2017-12-01

ZTEM is an airborne electromagnetic (EM) geophysical technique developed by Geotech Inc® where naturally propagated EM fields originating with regional and global lightning discharges (sferics) are measured as a means of inferring subsurface electrical resistivity structure. A helicopter-borne coil platform (bird) measuring the vertical component of magnetic (H) field variations along a flown profile is referenced to a pair of horizontal coils at a fixed location on the ground in order to estimate a tensor H-field transfer function. The ZTEM method is distinct from the traditional magnetotelluric (MT) method in that the electric (E) fields are not considered because of the technological challenge of measuring E-fields in the dielectric air medium. This can lend some non-uniqueness to ZTEM interpretation because a range of conductivity structures in the earth depending upon an assumed background earth resistivity model can fit ZTEM data to within tolerance. MT data do not suffer this particular problem, but they are cumbersome to acquire in their common need for land-based transport often in near-roadless areas and for laying out and digging the electrodes and H coils. The complementary nature of ZTEM and MT logistics and resolution has motivated development of schemes to acquire appropriate amounts of each data type in a single survey and to produce an earth image through joint inversion. In particular, consideration is given to surveys where only sparse MT soundings are needed to drastically reduce the non-uniqueness associated with background uncertainty while straining logistics minimally. Synthetic and field data are analysed using 2D and 3D finite element platforms developed for this purpose. Results to date suggest that indeed dense ZTEM surveys can provide detailed heterogeneous model images with large-scale averages constrained by a modest number of MT soundings. Further research is needed in determining the allowable degree of MT sparseness and the relative weighting of the two data sets in joint inversion.

Computational electronics and electromagnetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shang, C. C.

The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domainmore » CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.« less

Joint detection of anatomical points on surface meshes and color images for visual registration of 3D dental models

NASA Astrophysics Data System (ADS)

Destrez, Raphaël.; Albouy-Kissi, Benjamin; Treuillet, Sylvie; Lucas, Yves

2015-04-01

Computer aided planning for orthodontic treatment requires knowing occlusion of separately scanned dental casts. A visual guided registration is conducted starting by extracting corresponding features in both photographs and 3D scans. To achieve this, dental neck and occlusion surface are firstly extracted by image segmentation and 3D curvature analysis. Then, an iterative registration process is conducted during which feature positions are refined, guided by previously found anatomic edges. The occlusal edge image detection is improved by an original algorithm which follows Canny's poorly detected edges using a priori knowledge of tooth shapes. Finally, the influence of feature extraction and position optimization is evaluated in terms of the quality of the induced registration. Best combination of feature detection and optimization leads to a positioning average error of 1.10 mm and 2.03°.

Enhanced control of a flexure-jointed micromanipulation system using a vision-based servoing approach

NASA Astrophysics Data System (ADS)

Chuthai, T.; Cole, M. O. T.; Wongratanaphisan, T.; Puangmali, P.

2018-01-01

This paper describes a high-precision motion control implementation for a flexure-jointed micromanipulator. A desktop experimental motion platform has been created based on a 3RUU parallel kinematic mechanism, driven by rotary voice coil actuators. The three arms supporting the platform have rigid links with compact flexure joints as integrated parts and are made by single-process 3D printing. The mechanism overall size is approximately 250x250x100 mm. The workspace is relatively large for a flexure-jointed mechanism, being approximately 20x20x6 mm. A servo-control implementation based on pseudo-rigid-body models (PRBM) of kinematic behavior combined with nonlinear-PID control has been developed. This is shown to achieve fast response with good noise-rejection and platform stability. However, large errors in absolute positioning occur due to deficiencies in the PRBM kinematics, which cannot accurately capture flexure compliance behavior. To overcome this problem, visual servoing is employed, where a digital microscopy system is used to directly measure the platform position by image processing. By adopting nonlinear PID feedback of measured angles for the actuated joints as inner control loops, combined with auxiliary feedback of vision-based measurements, the absolute positioning error can be eliminated. With controller gain tuning, fast dynamic response and low residual vibration of the end platform can be achieved with absolute positioning accuracy within ±1 micron.

In vivo axial humero-ulnar rotation in normal and dysplastic canine elbow joints.

PubMed

Rohwedder, Thomas; Fischer, Martin; Böttcher, Peter

2018-04-01

To prospectively compare relative axial (internal-external) humero-ulnar rotation in normal and dysplastic canine elbow joints. Six normal elbows (five dogs) and seven joints (six dogs) with coronoid disease were examined. After implantation of 0.8 mm tantalum beads into humerus and ulna, biplanar x-ray movies of the implanted elbows were taken while dogs were walking on a treadmill. Based on the 2D bead coordinates of the synchronized x-ray movies virtual 3D humero-ulnar animations were calculated. Based on these, relative internal-external humero-ulnar rotation was measured over the first third of stance phase and expressed as maximal rotational amplitude. Amplitudes from three consecutive steps were averaged and groupwise compared using an unpaired t-test. In normal elbow joints mean axial relative humero-ulnar rotation was 2.9° (SD 1.1). Dysplastic joints showed a significantly greater rotational amplitude (5.3°, SD 2.0; p = 0.0229, 95% confidence interval 0.4-4.4). Dysplastic elbow joints show greater relative internal-external humero-ulnar rotation compared to normal elbows, which might reflect rotational joint instability. Increased relative internal-external humero-ulnar rotation might alter physiological joint contact and pressure patterns. Future studies are needed to verify if this plays a role in the pathogenesis of medial coronoid disease. Schattauer GmbH.

Repeatability of stance phase kinematics from a multi-segment foot model in people aged 50 years and older.

PubMed

Arnold, John B; Mackintosh, Shylie; Jones, Sara; Thewlis, Dominic

2013-06-01

Confidence in 3D multi-segment foot models has been limited by a lack of repeatability data, particularly in older populations that may display unique functional foot characteristics. This study aimed to determine the intra and inter-observer repeatability of stance phase kinematic data from a multi-segment foot model described by Leardini et al. [2] in people aged 50 years or older. Twenty healthy adults participated (mean age 65.4 years SD 8.4). A repeated measures study design was used with data collected from four testing sessions on two days from two observers. Intra (within-day and between-day) and inter-observer coefficient of multiple correlations revealed moderate to excellent similarity of stance phase joint range of motion (0.621-0.975). Relative to the joint range of motion (ROM), mean differences (MD) between sessions were highest for the within-day comparison for all planar ROM at the metatarsus-midfoot articulation (sagittal plane ROM 5.2° vs. 3.9°, MD 3.1°; coronal plane ROM 3.9 vs. 3.1°, MD 2.3°; transverse plane ROM 6.8° vs. 5.16°, MD 3.5°). Consequently, data from the metatarsus-midfoot articulation in the Istituto Ortopedico Rizzoli (IOR) foot model in adults aged over 50 years needs to be considered with respect to the findings of this study. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Micromechanisms of intergranular brittle ftacture in intermetallic compounds

NASA Astrophysics Data System (ADS)

Vitek, V.

1991-06-01

Grain boundaries in intermetallic compounds such as Ni3A1 are inherently brittle. The reason is usually sought in grain boundary cohesion but in metals even brittle fracture is accompanied by some local plasticity and thus not only cohesion but also dislocation mobility in the boundary region need to be studied. We first discuss here the role of an irreversible shear deformation at the crack tip during microcrack propagation assuming that these two processes are concomitant. It is shown that a pre-existing crack cannot propagate in a brittle manner once the dislocation emission occurs. However, if a microcrack nucleates during loading it can propagate concurrently with the development of the irreversible shear deformation at the crack tip. The latter is then the major energy dissipating process. In the second part of this paper we present results of atomistic studies of grain boundaries in Ni3A1 and CU3Au which suggest that substantial structural differences exist between strongly and weakly ordered L12 alloys. We discuss then the consequence of these differences for intergranular brittleness in the framework of the above model for microcrack propagation. On this basis we propose an explanation for the intrinsic intergranular brittleness in some L12 alloys and relate it directly to the strength of ordering. Les joints de grains dans les composés intermétalliques de type Ni3AI sont de nature fragile. L'origine de cette fragilité est habituellement dans la cohésion des joints de grains. Dans les métaux, cependant, même la rupture fragile est accompagnée d'une certaine déformation plastique locale, de telle sorte que non seulement la cohésion mais aussi la mobilité des dislocations près des joints doit être étudiée. Nous discutons d'abord le rôle d'une déformation en cisaillement irréversible en tête de fissure pendant la propagation de cette fissure, en supposant que les deux processus sont concomitants. Nous montrons qu'une fissure préexistante ne peut pas se propager de manière fragile, une fois que l'émission de dislocations se produit. Cependant, si une microfissure apparaît pendant le changement, elle peut se développer en concurrence avec le développement d'un cisaillement irréversible en tête de fissure. Ce demier est alors le principal mécanisme dissipatif d'énergie. Dans la deuxième partie de cet article, nous présentons des résultats d'études atomiques de joints de grain dans Ni3AI et CU3Au, suggérant qu'il existe des différences de structure substancielles entre les alliages L12 fortement et faiblement ordonnés. Nous discutons ensuite la conséquence de ces différences pour la fragilité intergranulaire, à l'aide du modèle ci-dessus pour la propagation des microfissures. Sur cette base, nous proposons une explication pour la fragilité intergranulaire intrinsèque de quelques alliages L12, et nous la relions directement au degré d'ordre.

Movement coordination patterns between the foot joints during walking.

PubMed

Arnold, John B; Caravaggi, Paolo; Fraysse, François; Thewlis, Dominic; Leardini, Alberto

2017-01-01

In 3D gait analysis, kinematics of the foot joints are usually reported via isolated time histories of joint rotations and no information is provided on the relationship between rotations at different joints. The aim of this study was to identify movement coordination patterns in the foot during walking by expanding an existing vector coding technique according to an established multi-segment foot and ankle model. A graphical representation is also described to summarise the coordination patterns of joint rotations across multiple patients. Three-dimensional multi-segment foot kinematics were recorded in 13 adults during walking. A modified vector coding technique was used to identify coordination patterns between foot joints involving calcaneus, midfoot, metatarsus and hallux segments. According to the type and direction of joints rotations, these were classified as in-phase (same direction), anti-phase (opposite directions), proximal or distal joint dominant. In early stance, 51 to 75% of walking trials showed proximal-phase coordination between foot joints comprising the calcaneus, midfoot and metatarsus. In-phase coordination was more prominent in late stance, reflecting synergy in the simultaneous inversion occurring at multiple foot joints. Conversely, a distal-phase coordination pattern was identified for sagittal plane motion of the ankle relative to the midtarsal joint, highlighting the critical role of arch shortening to locomotor function in push-off. This study has identified coordination patterns between movement of the calcaneus, midfoot, metatarsus and hallux by expanding an existing vector cording technique for assessing and classifying coordination patterns of foot joints rotations during walking. This approach provides a different perspective in the analysis of multi-segment foot kinematics, and may be used for the objective quantification of the alterations in foot joint coordination patterns due to lower limb pathologies or following injuries.

Low Activation Joining of SiC/SiC Composites for Fusion Applications: Modeling Thermal and Irradiation-induced Swelling Effects on Integrity of Ti3SiC2/SiC Joint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Ba Nghiep; Henager, Charles H.; Kurtz, Richard J.

This work developed a continuum damage mechanics model that incorporates thermal expansion combined with irradiation-induced swelling effects to study the origin of cracking observed in recent irradiation experiments. Micromechanical modeling using an Eshelby-Mori-Tanaka approach was used to compute the thermoelastic properties of the Ti3SiC2/SiC joint needed for the model. In addition, a microstructural dual-phase Ti3SiC2/SiC model was developed to determine irradiation-induced swelling of the composite joint at a given temperature resulting from differential swelling of SiC and the Ti3SiC2 MAX phase. Three cases for the miniature torsion hourglass (THG) specimens containing a Ti3SiC2/SiC joint were analyzed corresponding to three irradiationmore » temperatures: 800oC, 500oC, and 400oC.« less

Three-Dimensional Lower Extremity Joint Loading in a Carved Ski and Snowboard Turn: A Pilot Study

PubMed Central

Müller, Erich

2014-01-01

A large number of injuries to the lower extremity occur in skiing and snowboarding. Due to the difficulty of collecting 3D kinematic and kinetic data with high accuracy, a possible relationship between injury statistic and joint loading has not been studied. Therefore, the purpose of the current study was to compare ankle and knee joint loading at the steering leg between carved ski and snowboard turns. Kinetic data were collected using mobile force plates mounted under the toe and heel part of the binding on skies or snowboard (KISTLER). Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. An extended version of the Yeadon model was applied to calculate inertial properties of the segments. Ankle and knee joint forces and moments were calculated using inverse dynamic analysis. Results showed higher forces along the longitudinal axis in skiing and similar forces for skiing and snowboarding in anterior-posterior and mediolateral direction. Joint moments were consistently greater during a snowboard turn, but more fluctuations were observed in skiing. Hence, when comparing joint loading between carved ski and snowboard turns, one should differentiate between forces and moments, including the direction of forces and moments and the turn phase. PMID:25317202

A dual-phase microstructural approach to damage and fracture of Ti3SiC2/SiC joints

NASA Astrophysics Data System (ADS)

Nguyen, Ba Nghiep; Henager, Charles H.; Kurtz, Richard J.

2018-02-01

The microcracking mechanisms responsible for Ti3SiC2/SiC joint damage observed at the macroscopic scale after neutron irradiation experiments are investigated in detail. A dual-phase microstructural approach to damage and fracture of Ti3SiC2/SiC joints is developed that uses a finely discretized two-phase domain based on a digital image of an actual microstructure involving embedded Ti3SiC2 and SiC phases. The behaviors of SiC and Ti3SiC2 in the domain are described by the continuum damage mechanics (CDM) model reported in Nguyen et al., J. Nucl. Mater., 2017, 495:504-515. This CDM model describes microcracking damage in brittle ceramics caused by thermomechanical loading and irradiation-induced swelling. The dual-phase microstructural model is applied to predict the microcracking mechanisms occurring in a typical Ti3SiC2/SiC joint subjected to heating to 800 °C followed by irradiation-induced swelling at this temperature and cooling to room temperature after the applied swelling has reached the maximum swelling levels observed in the experiments for SiC and Ti3SiC2. The model predicts minor damage of the joint after heating but significant microcracking in the SiC phase and along the boundaries between SiC and Ti3SiC2 as well as along the bonding joint during irradiation-induced swelling and cooling to room temperature. These predictions qualitatively agree with the limited experimental observations of joint damage at this irradiation temperature.

Modeling the effect of preexisting joints on normal fault geometries using a brittle and cohesive material

NASA Astrophysics Data System (ADS)

Kettermann, M.; van Gent, H. W.; Urai, J. L.

2012-04-01

Brittle rocks, such as for example those hosting many carbonate or sandstone reservoirs, are often affected by different kinds of fractures that influence each other. Understanding the effects of these interactions on fault geometries and the formation of cavities and potential fluid pathways might be useful for reservoir quality prediction and production. Analogue modeling has proven to be a useful tool to study faulting processes, although usually the used materials do not provide cohesion and tensile strength, which are essential to create open fractures. Therefore, very fine-grained, cohesive, hemihydrate powder was used for our experiments. The mechanical properties of the material are scaling well for natural prototypes. Due to the fine grain size structures are preserved in in great detail. The used deformation box allows the formation of a half-graben and has initial dimensions of 30 cm width, 28 cm length and 20 cm height. The maximum dip-slip along the 60° dipping predefined basement fault is 4.5 cm and was fully used in all experiments. To setup open joints prior to faulting, sheets of paper placed vertically within the box to a depth of about 5 cm from top. The powder was then sieved into the box, embedding the paper almost entirely. Finally strings were used to remove the paper carefully, leaving open voids. Using this method allows the creation of cohesionless open joints while ensuring a minimum impact on the sensitive surrounding material. The presented series of experiments aims to investigate the effect of different angles between the strike of a rigid basement fault and a distinct joint set. All experiments were performed with a joint spacing of 2.5 cm and the fault-joint angles incrementally covered 0°, 4°, 8°, 12°, 16°, 20° and 25°. During the deformation time lapse photography from the top and side captured every structural change and provided data for post-processing analysis using particle imaging velocimetry (PIV). Additionally, stereo-photography at the final stage of deformation enabled the creation of 3D models to preserve basic geometric information. The models showed that at the surface the deformation localized always along preexisting joints, even when they strike at an angle to the basement-fault. In most cases faults intersect precisely at the maximum depth of the joints. With increasing fault-joint angle the deformation occurred distributed over several joints by forming stepovers with fractures oriented normal to the strike of the joints. No fractures were observed parallel to the basement fault. At low angles stepovers coincided with wedge-shaped structures between two joints that remain higher than the surrounding joint-fault intersection. The wide opening gap along the main fault allowed detailed observations of the fault planes at depth, which revealed (1) changing dips according to joint-fault angles, (2) slickenlines, (3) superimposed steepening fault-planes, causing sharp sawtooth-shaped structures. Comparison to a field analogue at Canyonlands National Park, Utah/USA showed similar structures and features such as vertical fault escarpments at the surface coinciding with joint-surfaces. In the field and in the models stepovers were observed as well as conjugate faulting and incremental fault-steepening.

An automatic 2D–3D image matching method for reproducing spatial knee joint positions using single or dual fluoroscopic images

PubMed Central

Zhu, Zhonglin; Li, Guoan

2013-01-01

Fluoroscopic image technique, using either a single image or dual images, has been widely applied to measure in vivo human knee joint kinematics. However, few studies have compared the advantages of using single and dual fluoroscopic images. Furthermore, due to the size limitation of the image intensifiers, it is possible that only a portion of the knee joint could be captured by the fluoroscopy during dynamic knee joint motion. In this paper, we presented a systematic evaluation of an automatic 2D–3D image matching method in reproducing spatial knee joint positions using either single or dual fluoroscopic image techniques. The data indicated that for the femur and tibia, their spatial positions could be determined with an accuracy and precision less than 0.2 mm in translation and less than 0.4° in orientation when dual fluoroscopic images were used. Using single fluoroscopic images, the method could produce satisfactory accuracy in joint positions in the imaging plane (average up to 0.5 mm in translation and 1.3° in rotation), but large variations along the out-plane direction (in average up to 4.0 mm in translation and 2.28 in rotation). The precision of using single fluoroscopic images to determine the actual knee positions was worse than its accuracy obtained. The data also indicated that when using dual fluoroscopic image technique, if the knee joint outlines in one image were incomplete by 80%, the algorithm could still reproduce the joint positions with high precisions. PMID:21806411

26 CFR 25.2523(d)-1 - Joint interests.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Joint interests. 25.2523(d)-1 Section 25.2523(d... TAXES GIFT TAX; GIFTS MADE AFTER DECEMBER 31, 1954 Deductions § 25.2523(d)-1 Joint interests. Section 2523(d) provides that if a property interest is transferred to the donee spouse as sole joint tenant...

Effects of footwear on three-dimensional tibiotalar and subtalar joint motion during running.

PubMed

Peltz, Cathryn D; Haladik, Jeffrey A; Hoffman, Scott E; McDonald, Michael; Ramo, Nicole L; Divine, George; Nurse, Matthew; Bey, Michael J

2014-08-22

Running is a popular form of recreation, but injuries are common and may be associated with abnormal joint motion. The objective of this study was to determine the effect of three footwear conditions - barefoot (BF), an ultraflexible training shoe (FREE), and a motion control shoe (MC) - on 3D foot and ankle motion. Dynamic, biplane radiographic images were acquired from 12 runners during overground running. 3D rotations of the tibiotalar and subtalar joints were quantified in terms of plantarflexion/dorsiflexion (PF/DF), inversion/eversion (IN/EV) and internal/external rotation (IR/ER). Across the early stance phase (defined as footstrike to heel-off), BF running demonstrated greater tibiotalar joint range of motion for PF/DF (28.2 ± 8.3°) and IR/ER (7.0 ± 1.4°) than the shod conditions (FREE: PF/DF=15.1 ± 5.9°, IR/ER=4.8 ± 2.1°; MC: PF/DF=15.0 ± 6.2°, IR/ER=4.3 ± 0.7°). Also at the tibiotalar joint, BF running resulted in a position significantly more plantarflexed (BF: 2.0 ± 12.5°, FREE: 15.7 ± 12.2°, MC: 16.5 ± 9.3°) and internally rotated (BF: 12.9 ± 4.5°, FREE: 10.7 ± 4.3°, MC: 10.6 ± 3.9°) at footstrike compared to both shod conditions. No differences were detected between the shod conditions at any point in the early stance phase at the tibiotalar joint. The MC condition demonstrated significant differences compared to FREE at several points throughout the early stance phase at the subtalar joint, with the greatest differences seen at 30% in PF/DF (MC -1.4 ± 8.8°: FREE: -0.5 ± 9.0°), IN/EV (MC -8.1 ± 5.7°: FREE -6.3 ± 5.5°) and IR/ER (MC -9.5 ± 5.3°: FREE: -8.7 ± 5.2°). These findings indicate that footwear has subtle effects on joint motion mainly between BF and shod conditions at the tibiotalar joint and between shod conditions at the subtalar joint. Copyright © 2014 Elsevier Ltd. All rights reserved.

2D data-space cross-gradient joint inversion of MT, gravity and magnetic data

NASA Astrophysics Data System (ADS)

Pak, Yong-Chol; Li, Tonglin; Kim, Gang-Sop

2017-08-01

We have developed a data-space multiple cross-gradient joint inversion algorithm, and validated it through synthetic tests and applied it to magnetotelluric (MT), gravity and magnetic datasets acquired along a 95 km profile in Benxi-Ji'an area of northeastern China. To begin, we discuss a generalized cross-gradient joint inversion for multiple datasets and model parameters sets, and formulate it in data space. The Lagrange multiplier required for the structural coupling in the data-space method is determined using an iterative solver to avoid calculation of the inverse matrix in solving the large system of equations. Next, using model-space and data-space methods, we inverted the synthetic data and field data. Based on our result, the joint inversion in data-space not only delineates geological bodies more clearly than the separate inversion, but also yields nearly equal results with the one in model-space while consuming much less memory.

Multijoint kinetic chain analysis of knee extension during the soccer instep kick.

PubMed

Naito, Kozo; Fukui, Yosuke; Maruyama, Takeo

2010-04-01

Although previous studies have shown that motion-dependent interactions between adjacent segments play an important role in producing knee extension during the soccer instep kick, detailed knowledge about the mechanisms underlying those interactions is lacking. The present study aimed to develop a 3-D dynamical model for the multijoint kinetic chain of the instep kick in order to quantify the contributions of the causal dynamical factors to the production of maximum angular velocity during knee extension. Nine collegiate soccer players volunteered to participate in the experiment and performed instep kicking movements while 3-D positional data and the ground reaction force were measured. A dynamical model was developed in the form of a linked system containing 8 segments and 18 joint rotations, and the knee extension/flexion motion was decomposed into causal factors related to muscular moment, gyroscopic moment, centrifugal force, Coriolis force, gravity, proximal endpoint linear acceleration, and external force-dependent terms. The rapid knee extension during instep kicking was found to result almost entirely from kicking leg centrifugal force, trunk rotation muscular moment, kicking leg Coriolis force, and trunk rotation gyroscopic-dependent components. Based on the finding that rapid knee extension during instep kicking stems from multiple dynamical factors, it is suggested that the multijoint kinetic chain analysis used in the present study is more useful for achieving a detailed understanding of the cause of rapid kicking leg movement than the previously used 2-D, two-segment kinetic chain model. The present results also indicated that the centrifugal effect due to the kicking hip flexion angular velocity contributed substantially to the generation of a rapid knee extension, suggesting that the adjustment between the kicking hip flexion angular velocity and the leg configuration (knee flexion angle) is more important for effective instep kicking than other joint kinematics.

The application of 3D image processing to studies of the musculoskeletal system

NASA Astrophysics Data System (ADS)

Hirsch, Bruce Elliot; Udupa, Jayaram K.; Siegler, Sorin; Winkelstein, Beth A.

2009-10-01

Three dimensional renditions of anatomical structures are commonly used to improve visualization, surgical planning, and patient education. However, such 3D images also contain information which is not readily apparent, and which can be mined to elucidate, for example, such parameters as joint kinematics, spacial relationships, and distortions of those relationships with movement. Here we describe two series of experiments which demonstrate the functional application of 3D imaging. The first concerns the joints of the ankle complex, where the usual description of motions in the talocrural joint is shown to be incomplete, and where the roles of the anterior talofibular and calcaneofibular ligaments are clarified in ankle sprains. Also, the biomechanical effects of two common surgical procedures for repairing torn ligaments were examined. The second series of experiments explores changes in the anatomical relationships between nerve elements and the cervical vertebrae with changes in neck position. They provide preliminary evidence that morphological differences may exist between asymptomatic subjects and patients with radiculopathy in certain positions, even when conventional imaging shows no difference.

Use of integrated analogue and numerical modelling to predict tridimensional fracture intensity in fault-related-folds.

NASA Astrophysics Data System (ADS)

Pizzati, Mattia; Cavozzi, Cristian; Magistroni, Corrado; Storti, Fabrizio

2016-04-01

Fracture density pattern predictions with low uncertainty is a fundamental issue for constraining fluid flow pathways in thrust-related anticlines in the frontal parts of thrust-and-fold belts and accretionary prisms, which can also provide plays for hydrocarbon exploration and development. Among the drivers that concur to determine the distribution of fractures in fold-and-thrust-belts, the complex kinematic pathways of folded structures play a key role. In areas with scarce and not reliable underground information, analogue modelling can provide effective support for developing and validating reliable hypotheses on structural architectures and their evolution. In this contribution, we propose a working method that combines analogue and numerical modelling. We deformed a sand-silicone multilayer to eventually produce a non-cylindrical thrust-related anticline at the wedge toe, which was our test geological structure at the reservoir scale. We cut 60 serial cross-sections through the central part of the deformed model to analyze faults and folds geometry using dedicated software (3D Move). The cross-sections were also used to reconstruct the 3D geometry of reference surfaces that compose the mechanical stratigraphy thanks to the use of the software GoCad. From the 3D model of the experimental anticline, by using 3D Move it was possible to calculate the cumulative stress and strain underwent by the deformed reference layers at the end of the deformation and also in incremental steps of fold growth. Based on these model outputs it was also possible to predict the orientation of three main fractures sets (joints and conjugate shear fractures) and their occurrence and density on model surfaces. The next step was the upscaling of the fracture network to the entire digital model volume, to create DFNs.

Rockfall hazard assessment of nearly vertical rhyolite tuff cliff faces by using terrestrial laser scanner, UAV and FEM analyses

NASA Astrophysics Data System (ADS)

Török, Ákos; Barsi, Árpád; Görög, Péter; Lovas, Tamás; Bögöly, Gyula; Czinder, Balázs; Vásárhelyi, Balázs; Molnár, Bence; József Somogyi, Árpád

2017-04-01

Nearly vertical rhyolite tuff cliff faces are located in NE-Hungary representing rock fall hazard in the touristic region of Sirok. Larger blocks of the cliff have fallen in recent years menacing tourists and human lives. The rhyolite tuff, that forms the Castle Hill was formed during Miocene volcanism and comprises of brecciated lapilli tuffs and tuffs with intercalating ignimbritic horizons. The paper focuses on the 3D mapping of cliff faces and modeling of rock fall hazard. The topography and 3D model of the cliff was obtained by using GNSS supported terrestrial laser scanner and UAV. With imaging techniques of UAV a Triangulated Irregular Network (TIN) model was developed that contained triangles with 5-10 cm side lengths. GNSS supported terrestrial laser scanning allowed the observation with a resolution 1-5 cm of point spacing. The point clouds were further processed and with the combination of laser scanner and UAV data a 3D model of the studied cliff faces were obtained. Geological parameters for rock fall analyses included both field observations and laboratory tests. The lithotypes were identified on the field and were sampled for rock mechanical laboratory analyses. Joint- and fault system was mapped and visualized by using Rocscience Dip. EN test methods were used to obtain the density properties of various lithotypes of rhyolite tuff. Other standardized EN tests included ultrasonic pulse velocity, water absorption, indirect tensile strength (Brasilian), uniaxial compressive strength and modulus of elasticity of air dry and of water saturated samples. GSI values were denoted based on filed observations and rock mass properties. The stability analyses of cliff faces were made by using 2D FEM software (Phase 2). Cross sections were evaluated and global factor of safety was also calculated. The modeled displacements were in the order of few centimeters; however several locations were pinpointed where wedge failure and planar slip surfaces were identified as major cliff stability hazards. These were associated with the major joint systems dissecting cliff faces. This research have proved that the combined methods of field surveying, imaging techniques, data processing and FEM modelling with rock mechanical laboratory analyses allowed the identification of major rock fall hazards even at areas which are difficult to access.

Contribution of calcaneal and leg segment rotations to ankle joint dorsiflexion in a weight-bearing task.

PubMed

Chizewski, Michael G; Chiu, Loren Z F

2012-05-01

Joint angle is the relative rotation between two segments where one is a reference and assumed to be non-moving. However, rotation of the reference segment will influence the system's spatial orientation and joint angle. The purpose of this investigation was to determine the contribution of leg and calcaneal rotations to ankle rotation in a weight-bearing task. Forty-eight individuals performed partial squats recorded using a 3D motion capture system. Markers on the calcaneus and leg were used to model leg and calcaneal segment, and ankle joint rotations. Multiple linear regression was used to determine the contribution of leg and calcaneal segment rotations to ankle joint dorsiflexion. Regression models for left (R(2)=0.97) and right (R(2)=0.97) ankle dorsiflexion were significant. Sagittal plane leg rotation had a positive influence (left: β=1.411; right: β=1.418) while sagittal plane calcaneal rotation had a negative influence (left: β=-0.573; right: β=-0.650) on ankle dorsiflexion. Sagittal plane rotations of the leg and calcaneus were positively correlated (left: r=0.84, P<0.001; right: r=0.80, P<0.001). During a partial squat, the calcaneus rotates forward. Simultaneous forward calcaneal rotation with ankle dorsiflexion reduces total ankle dorsiflexion angle. Rear foot posture is reoriented during a partial squat, allowing greater leg rotation in the sagittal plane. Segment rotations may provide greater insight into movement mechanics that cannot be explained via joint rotations alone. Copyright © 2012 Elsevier B.V. All rights reserved.

Complex crustal structures: their 3D grav/mag modelling and 3D printing

NASA Astrophysics Data System (ADS)

Götze, Hans-Jürgen; Schmidt, Sabine; Menzel, Peter

2017-04-01

Our new techniques for modelling and visualization are user-friendly because they are highly interactive, ideally real-time and topology conserving and can be used for both flat and spherical models in 3D. These are important requirements for joint inversion for gravity and magnetic modelling of fields and their derivatives, constrained by seismic and structural input from independent data sources. A borehole tool for magnetic and gravity modelling will also be introduced. We are already close to satisfying the demand of treating several geophysical methods in a single model for subsurface evaluation purposes and aim now for fulfilling most of the constraints: consistency of modelling results and measurements and geological plausibility as well. For 3D modelling, polyhedrons built by triangles are used. All elements of the gravity and magnetic tensors can be included. In the modelling interface, after geometry changes the effect on the model is quickly updated because only the changed triangles have to be recalculated. Because of the triangular model structure, our approach can handle complex structures very well and flexible (e.g. overhangs of salt domes or plumes). For regional models, the use of spherical geometries and calculations is necessary and available. 3D visualization is performed with a 3D-printer (Ultimaker 2) and gives new insights into even rather complicated Earth subsurface structures. Inversion can either be run over the whole model, but typically it is used in smaller parts of the model, helping to solve local problems and/or proving/disproving local hypotheses. The basic principles behind this interactive approach are high performance optimized algorithms (CMA-ES: Covariance-matrix-adoption-evolution-strategy). The efficiency of the algorithm is rather good in terms of stable convergence due to topological model validity. Potential field modelling is always influenced by edge effects. To avoid this, a simple but very robust method has been developed: Derive a density/susceptibility-depth function by taking the mean value of the borders of depth slices through the model. The focus of the presentation is set on two practical examples: From the international KTB - Project, Germanýs deep continental borehole as well as a very complex salt structure in the Northwest German Basin.

Experience with the use of a partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft.

PubMed

Birk, Stephanie; Brase, Christoph; Hornung, Joachim

2014-08-01

In the further development of alloplastic prostheses for use in middle ear surgery, the Dresden and Cologne University Hospitals, working together with a company, introduced a new partial ossicular replacement prosthesis in 2011. The ball-and-socket joint between the prosthesis and the shaft mimics the natural articulations between the malleus and incus and between the incus and stapes, allowing reaction to movements of the tympanic membrane graft, particularly during the healing process. Retrospective evaluation To reconstruct sound conduction as part of a type III tympanoplasty, partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft was implanted in 60 patients, with other standard partial ossicular replacement prosthesis implanted in 40 patients and 64 patients. Pure-tone audiometry was carried out, on average, 19 and 213 days after surgery. Results of the partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft were compared with those of the standard prostheses. Early measurements showed a mean improvement of 3.3 dB in the air-bone gap (ABG) with the partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft, giving similar results than the standard implants (6.6 and 6.0 dB, respectively), but the differences were not statistically significant. Later measurements showed a statistically significant improvement in the mean ABG, 11.5 dB, compared with 4.4 dB for one of the standard partial ossicular replacement prosthesis and a tendency of better results to 6.9 dB of the other standard prosthesis. In our patients, we achieved similarly good audiometric results to those already published for the partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft. Intraoperative fixation posed no problems, and the postoperative complication rate was low.

Simultaneous segmentation of the bone and cartilage surfaces of a knee joint in 3D

NASA Astrophysics Data System (ADS)

Yin, Y.; Zhang, X.; Anderson, D. D.; Brown, T. D.; Hofwegen, C. Van; Sonka, M.

2009-02-01

We present a novel framework for the simultaneous segmentation of multiple interacting surfaces belonging to multiple mutually interacting objects. The method is a non-trivial extension of our previously reported optimal multi-surface segmentation. Considering an example application of knee-cartilage segmentation, the framework consists of the following main steps: 1) Shape model construction: Building a mean shape for each bone of the joint (femur, tibia, patella) from interactively segmented volumetric datasets. Using the resulting mean-shape model - identification of cartilage, non-cartilage, and transition areas on the mean-shape bone model surfaces. 2) Presegmentation: Employment of iterative optimal surface detection method to achieve approximate segmentation of individual bone surfaces. 3) Cross-object surface mapping: Detection of inter-bone equidistant separating sheets to help identify corresponding vertex pairs for all interacting surfaces. 4) Multi-object, multi-surface graph construction and final segmentation: Construction of a single multi-bone, multi-surface graph so that two surfaces (bone and cartilage) with zero and non-zero intervening distances can be detected for each bone of the joint, according to whether or not cartilage can be locally absent or present on the bone. To define inter-object relationships, corresponding vertex pairs identified using the separating sheets were interlinked in the graph. The graph optimization algorithm acted on the entire multiobject, multi-surface graph to yield a globally optimal solution. The segmentation framework was tested on 16 MR-DESS knee-joint datasets from the Osteoarthritis Initiative database. The average signed surface positioning error for the 6 detected surfaces ranged from 0.00 to 0.12 mm. When independently initialized, the signed reproducibility error of bone and cartilage segmentation ranged from 0.00 to 0.26 mm. The results showed that this framework provides robust, accurate, and reproducible segmentation of the knee joint bone and cartilage surfaces of the femur, tibia, and patella. As a general segmentation tool, the developed framework can be applied to a broad range of multi-object segmentation problems.

Information Management Utilizing Valued Information at the Right Time (VIRT) as Applied to a Joint Terminal Attack Controller (JTAC) Mission

DTIC Science & Technology

2008-03-01

technology in an effective way without taking a decade for implementation. 15. NUMBER OF PAGES 77 14. SUBJECT TERMS VIRT, Model Based... effective way without taking a decade for implementation. vi THIS PAGE INTENTIONALLY LEFT BLANK vii TABLE OF CONTENTS I. INTRODUCTION...To build the most effective force for 2020, we must be fully joint.”2 What does being fully joint mean and how does the DoD take advantage of

Seismics-electrics Joint Interpretation in a gypsiferous context.

NASA Astrophysics Data System (ADS)

Marzan, Ignacio; Marti, David; Lobo, Agustin; Alvarez-Marron, Joaquina; Carbonell, Ramon

2016-04-01

The main objective of this study is to improve the geophysical characterization resulting from a shallow 3D high resolution travel-time tomography survey (500x500m). This survey was acquired in Villar de Cañas (Cuenca, Spain) in late 2013 and early 2014. Lithology down to 150 m depth in this site is characterized by endorheic sediments, mainly siltstone and gypsum. After processing the tomography data, the velocity model showed a good correlation with geology models and borehole data except for the siltstone-gypsum transition. The model involves two lithological limits: the "transition layer - massive gypsum layer" (well resolved by a relatively high velocity contrast) and the "siltstone layer - transition layer" (constrained only in the central part of the model by a relatively low velocity contrast). As electrical resistivity is able to characterize shale-gypsum transitions, we complemented the seismic data with results from a collection of 2D ERT surveys, for which we build a new 3D grid with 2 parameters by node: velocity and resistivity. In order to derive a geological interpretation, we apply a statistical classification method (Linear Discriminant Analysis) to the new bi-parametric grid, using reference classes from well logs. This process results on a final 3D lithological model with less ambiguity and thus with a better definition of the two limits under discussion. Our study shows that the integration of seismic and electric methods significantly improves geological characterization in a gypsiferous context.

Virtual arthroscopy of the visible human female temporomandibular joint.

PubMed

Ishimaru, T; Lew, D; Haller, J; Vannier, M W

1999-07-01

This study was designed to obtain views of the temporomandibular joint (TMJ) by means of computed arthroscopic simulation (virtual arthroscopy) using three-dimensional (3D) processing. Volume renderings of the TMJ from very thin cryosection slices of the Visible Human Female were taken off the Internet. Analyze(AVW) software (Biomedical Imaging Resource, Mayo Foundation, Rochester, MN) on a Silicon Graphics 02 workstation (Mountain View, CA) was then used to obtain 3D images and allow the navigation "fly-through" of the simulated joint. Good virtual arthroscopic views of the upper and lower joint spaces of both TMJs were obtained by fly-through simulation from the lateral and endaural sides. It was possible to observe the presence of a partial defect in the articular disc and an osteophyte on the condyle. Virtual arthroscopy provided visualization of regions not accessible to real arthroscopy. These results indicate that virtual arthroscopy will be a new technique to investigate the TMJ of the patient with TMJ disorders in the near future.

Basin Characterisation by Means of Joint Inversion of Electromagnetic Geophysical Data, Borehole Data and Multivariate Statistical Methods: The Loop Head Peninsula, Western Ireland, Case Study

NASA Astrophysics Data System (ADS)

Campanya, J. L.; Ogaya, X.; Jones, A. G.; Rath, V.; McConnell, B.; Haughton, P.; Prada, M.

2016-12-01

The Science Foundation Ireland funded project IRECCSEM project (www.ireccsem.ie) aims to evaluate Ireland's potential for onshore carbon sequestration in saline aquifers by integrating new electromagnetic geophysical data with existing geophysical and geological data. One of the objectives of this component of IRECCSEM is to characterise the subsurface beneath the Loop Head Peninsula (part of Clare Basin, Co. Clare, Ireland), and identify major electrical resistivity structures that can guide an interpretation of the carbon sequestration potential of this area. During the summer of 2014, a magnetotelluric (MT) survey was carried out on the Loop Head Peninsula, and data from a total of 140 sites were acquired, including audio-magnetotelluric (AMT), and broadband magnetotelluric (BBMT). The dataset was used to generate shallow three-dimensional (3-D) electrical resistivity models constraining the subsurface to depths of up to 3.5 km. The three-dimensional (3-D) joint inversions were performed using three different types of electromagnetic data: MT impedance tensor (Z), geomagnetic transfer functions (T), and inter-station horizontal magnetic transfer-functions (H). The interpretation of the results was complemented with second-derivative models of the resulting electrical resistivity models, and a quantitative comparison with borehole data using multivariate statistical methods. Second-derivative models were used to define the main interfaces between the geoelectrical structures, facilitating superior comparison with geological and seismic results, and also reducing the influence of the colour scale when interpreting the results. Specific analysis was performed to compare the extant borehole data with the electrical resistivity model, identifying those structures that are better characterised by the resistivity model. Finally, the electrical resistivity model was also used to propagate some of the physical properties measured in the borehole, when a good relation was possible between the different types of data. The final results were compared with independent geological and geophysical data for a high-quality interpretation.

A Nonrigid Kernel-Based Framework for 2D-3D Pose Estimation and 2D Image Segmentation

PubMed Central

Sandhu, Romeil; Dambreville, Samuel; Yezzi, Anthony; Tannenbaum, Allen

2013-01-01

In this work, we present a nonrigid approach to jointly solving the tasks of 2D-3D pose estimation and 2D image segmentation. In general, most frameworks that couple both pose estimation and segmentation assume that one has exact knowledge of the 3D object. However, under nonideal conditions, this assumption may be violated if only a general class to which a given shape belongs is given (e.g., cars, boats, or planes). Thus, we propose to solve the 2D-3D pose estimation and 2D image segmentation via nonlinear manifold learning of 3D embedded shapes for a general class of objects or deformations for which one may not be able to associate a skeleton model. Thus, the novelty of our method is threefold: First, we present and derive a gradient flow for the task of nonrigid pose estimation and segmentation. Second, due to the possible nonlinear structures of one’s training set, we evolve the preimage obtained through kernel PCA for the task of shape analysis. Third, we show that the derivation for shape weights is general. This allows us to use various kernels, as well as other statistical learning methodologies, with only minimal changes needing to be made to the overall shape evolution scheme. In contrast with other techniques, we approach the nonrigid problem, which is an infinite-dimensional task, with a finite-dimensional optimization scheme. More importantly, we do not explicitly need to know the interaction between various shapes such as that needed for skeleton models as this is done implicitly through shape learning. We provide experimental results on several challenging pose estimation and segmentation scenarios. PMID:20733218

Preliminary 2-D shell analysis of the space shuttle solid rocket boosters

NASA Technical Reports Server (NTRS)

Knight, Norman F., Jr.; Gillian, Ronnie E.; Nemeth, Michael P.

1987-01-01

A two-dimensional shell model of an entire solid rocket booster (SRB) has been developed using the STAGSC-1 computer code and executed on the Ames CRAY computer. The purpose of these analyses is to calculate the overall deflection and stress distributions for the SRB when subjected to mechanical loads corresponding to critical times during the launch sequence. The mechanical loading conditions for the full SRB arise from the external tank (ET) attachment points, the solid rocket motor (SRM) pressure load, and the SRB hold down posts. The ET strut loads vary with time after the Space Shuttle main engine (SSME) ignition. The SRM internal pressure varies axially by approximately 100 psi. Static analyses of the full SRB are performed using a snapshot picture of the loads. The field and factory joints are modeled by using equivalent stiffness joints instead of detailed models of the joint. As such, local joint behavior cannot be obtained from this global model.

Automated bone segmentation from large field of view 3D MR images of the hip joint

NASA Astrophysics Data System (ADS)

Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S.; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

2013-10-01

Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation.

Automated bone segmentation from large field of view 3D MR images of the hip joint.

PubMed

Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

2013-10-21

Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation.

A protocol avoiding allogeneic transfusion in joint arthroplasties.

PubMed

Suh, You-Sung; Nho, Jae-Hwi; Choi, Hyung-Suk; Ha, Yong-Chan; Park, Jong-Seok; Koo, Kyung-Hoi

2016-09-01

Arthroplasties of hip and knee are associated with blood loss, which may lead to adverse patient outcome. Performing arthroplasties in Jehovah's Witness patients who do not accept transfusion has been a matter of concern. We developed a protocol, which avoids transfusion in arthroplasties of Jehovah's Witness patients, and evaluated the feasibility and safety of the protocol. The target of preoperative hemoglobin was more than 10 g/dL. When preoperative hemoglobin was lower than 10 g/dL, 4000 U erythropoietin (3 times a week) and 100 mg iron supplement (every day) were administered until the hemoglobin reached 10 g/dL. When the preoperative hemoglobin was higher than 10 g/dL, 4000 U erythropoietin and 100 mg iron supplement were administered once, before operation. During the operation, cell saver was used. Postoperatively, erythropoietin and iron supplements were administered until the hemoglobin reached 10 g/dL, similar to the preoperative protocol. We evaluated the feasibility of our protocol, perioperative complications and hematologic changes. From 2002 to 2014, 186 Witness patients visited our department. In 179 patients (96.2 %), 77 total knee arthroplasties, 69 bipolar hemiarthroplasties and 33 total hip arthroplasties were performed. The mean hemoglobin level was 12.3 g/dL preoperatively, 9.4 g/dL on postoperative day 3 and 10.3 g/dL on postoperative day 7. One patient died immediately after the arthroplasty and the remaining 178 patients survived. Total joint arthroplasty could be done without transfusion using this protocol in most of our patients. The rates of infection and mortality were similar with known infection and mortality rates of arthroplasties. In patients who do not want allogeneic transfusions, our protocol is a safe alternative to perform joint arthroplasties.

Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

NASA Astrophysics Data System (ADS)

Török, Ákos; Barsi, Árpád; Bögöly, Gyula; Lovas, Tamás; Somogyi, Árpád; Görög, Péter

2018-02-01

Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System) was used to collect images which were processed by Pix4D mapper (structure from motion technology) to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS) with the use of seven ground control points. The obtained digital surface model (DSM) was processed (vegetation removal) and the derived digital terrain model (DTM) allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method). Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE-WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS).

Long-Wavelength Elastic Wave Propagation Across Naturally Fractured Rock Masses

NASA Astrophysics Data System (ADS)

Mohd-Nordin, Mohd Mustaqim; Song, Ki-Il; Cho, Gye-Chun; Mohamed, Zainab

2014-03-01

Geophysical site investigation techniques based on elastic waves have been widely used to characterize rock masses. However, characterizing jointed rock masses by using such techniques remains challenging because of a lack of knowledge about elastic wave propagation in multi-jointed rock masses. In this paper, the roughness of naturally fractured rock joint surfaces is estimated by using a three-dimensional (3D) image-processing technique. The classification of the joint roughness coefficient (JRC) is enhanced by introducing the scan line technique. The peak-to-valley height is selected as a key indicator for JRC classification. Long-wavelength P-wave and torsional S-wave propagation across rock masses containing naturally fractured joints are simulated through the quasi-static resonant column (QSRC) test. In general, as the JRC increases, the S-wave velocity increases within the range of stress levels considered in this paper, whereas the P-wave velocity and the damping ratio of the shear wave decrease. In particular, the two-dimensional joint specimen underestimates the S-wave velocity while overestimating the P-wave velocity. This suggests that 3D joint surfaces should be implicated to obtain the reliable elastic wave velocity in jointed rock masses. The contact characteristic and degree of roughness and waviness of the joint surface are identified as a factor influencing P-wave and S-wave propagation in multi-jointed rock masses. The results indicate a need for a better understanding of the sensitivity of contact area alterations to the elastic wave velocity induced by changes in normal stress. This paper's framework can be a reference for future research on elastic wave propagation in naturally multi-jointed rock masses.

Trans-Dimensional Bayesian Imaging of 3-D Crustal and Upper Mantle Structure in Northeast Asia

NASA Astrophysics Data System (ADS)

Kim, S.; Tkalcic, H.; Rhie, J.; Chen, Y.

2016-12-01

Imaging 3-D structures using stepwise inversions of ambient noise and receiver function data is now a routine work. Here, we carry out the inversion in the trans-dimensional and hierarchical extension of the Bayesian framework to obtain rigorous estimates of uncertainty and high-resolution images of crustal and upper mantle structures beneath Northeast (NE) Asia. The methods inherently account for data sensitivities by means of using adaptive parameterizations and treating data noise as free parameters. Therefore, parsimonious results from the methods are balanced out between model complexity and data fitting. This allows fully exploiting data information, preventing from over- or under-estimation of the data fit, and increases model resolution. In addition, the reliability of results is more rigorously checked through the use of Bayesian uncertainties. It is shown by various synthetic recovery tests that complex and spatially variable features are well resolved in our resulting images of NE Asia. Rayleigh wave phase and group velocity tomograms (8-70 s), a 3-D shear-wave velocity model from depth inversions of the estimated dispersion maps, and regional 3-D models (NE China, the Korean Peninsula, and the Japanese islands) from joint inversions with receiver function data of dense networks are presented. High-resolution models are characterized by a number of tectonically meaningful features. We focus our interpretation on complex patterns of sub-lithospheric low velocity structures that extend from back-arc regions to continental margins. We interpret the anomalies in conjunction with distal and distributed intraplate volcanoes in NE Asia. Further discussion on other imaged features will be presented.

Altered control strategy between leading and trailing leg increases knee adduction moment in the elderly while descending stairs.

PubMed

Karamanidis, Kiros; Arampatzis, Adamantios

2011-02-24

The aim of the study was to examine the external knee adduction moments in a group of older and younger adults while descending stairs and thus the possibility of an increased risk of knee osteoarthritis due to altered knee joint loading in the elderly. Twenty-seven older and 16 younger adults descended a purpose-built staircase. A motion capture system and a force plate were used to determine the subjects' 3D kinematics and ground reaction forces (GRF) during locomotion. Calculation of the leg kinematics and kinetics was done by means of a rigid, three-segment, 3D leg model. In the initial portion of the support phase, older adults showed a more medio-posterior GRF vector relative to the ankle joint, leading to lower ankle joint moments (P<0.05). At the knee, the older adults demonstrated a more medio-posterior directed GRF vector, increasing in knee flexion and adduction in the second part of the single support phase (P<0.05). Further, GRF magnitude was lower in the initial and higher in the mid-portions of the support phase for the elderly (P<0.05). The results show that older adults descend stairs by using the trailing leg before the initiation of the double support phase more compared to the younger ones. The consequence of this altered control strategy while stepping down is a more medially directed GRF vector increasing the magnitude of external knee adduction moment in the elderly. The observed changes between leading and trailing leg in the elderly may cause a redistribution of the mechanical load at the tibiofemoral joint, affecting the initiation and progression of knee osteoarthritis in the elderly. Copyright © 2010 Elsevier Ltd. All rights reserved.

A methodology to accurately quantify patellofemoral cartilage contact kinematics by combining 3D image shape registration and cine-PC MRI velocity data.

PubMed

Borotikar, Bhushan S; Sipprell, William H; Wible, Emily E; Sheehan, Frances T

2012-04-05

Patellofemoral osteoarthritis and its potential precursor patellofemoral pain syndrome (PFPS) are common, costly, and debilitating diseases. PFPS has been shown to be associated with altered patellofemoral joint mechanics; however, an actual variation in joint contact stresses has not been established due to challenges in accurately quantifying in vivo contact kinematics (area and location). This study developed and validated a method for tracking dynamic, in vivo cartilage contact kinematics by combining three magnetic resonance imaging (MRI) techniques, cine-phase contrast (CPC), multi-plane cine (MPC), and 3D high-resolution static imaging. CPC and MPC data were acquired from 12 healthy volunteers while they actively extended/flexed their knee within the MRI scanner. Since no gold standard exists for the quantification of in vivo dynamic cartilage contact kinematics, the accuracy of tracking a single point (patellar origin relative to the femur) represented the accuracy of tracking the kinematics of an entire surface. The accuracy was determined by the average absolute error between the PF kinematics derived through registration of MPC images to a static model and those derived through integration of the CPC velocity data. The accuracy ranged from 0.47 mm to 0.77 mm for the patella and femur and from 0.68 mm to 0.86 mm for the patellofemoral joint. For purely quantifying joint kinematics, CPC remains an analytically simpler and more accurate (accuracy <0.33 mm) technique. However, for application requiring the tracking of an entire surface, such as quantifying cartilage contact kinematics, this combined imaging approach produces accurate results with minimal operator intervention. Published by Elsevier Ltd.

[The efficiency of the application of the modern computed technologies in the clinical practice and the prospects for the further use of the biomechanical 3D-models in forensic medicine].

PubMed

Makarov, I Yu; Svetlakov, A V; Sotin, A V; Shigeev, S V; Gusarov, A A; Smirenin, S A; Emelin, V V; Stragis, V B; Fetisov, V A

2018-01-01

To-day, the computer-assisted 3D-technologies for the mathematical simulation of the engineering facilities are extensively used for the purpose of technical calculations in all branches of industry and building. The positive experience gained with the application of the 3D-models finds wide application in the joined investigations on the topical problems of the prosthetic and surgical treatment of bones, teeth, joints, cardiac valves, blood vessels, etc. The objective of the present study was the analysis of the positive experience with the involvement of the specialists in the design and practical application of 3D-models for the solution of problems facing the medical prosthetics and the management of various pathological conditions. Another objective was to discuss the possible prospects for the interdisciplinary collaboration in these fields with a view to improving the quality of expert conclusions in the framework of forensic medical and criminalistics examinations. The data readily available from the official domestic and foreign Internet resources were used for the purpose of the study. The analysis of the published data has demonstrated the obvious advantages of the application of the mathematical 3D-models and the biomechanical studies for the solution of the concrete medico-biological problems. The currently available positive experience gained due to the participation of domestic specialists in biomechanics in the solution of the specific clinical problems gives hope that their collaboration between themselves and with the forensic medical experts will open up the promising prospects for the further investigations of the issues of common interest.

Internal Fixation of Complicated Acetabular Fractures Directed by Preoperative Surgery with 3D Printing Models.

PubMed

Liu, Zhao-Jie; Jia, Jian; Zhang, Yin-Guang; Tian, Wei; Jin, Xin; Hu, Yong-Cheng

2017-05-01

The purpose of this article is to evaluate the efficacy and feasibility of preoperative surgery with 3D printing-assisted internal fixation of complicated acetabular fractures. A retrospective case review was performed for the above surgical procedure. A 23-year-old man was confirmed by radiological examination to have fractures of multiple ribs, with hemopneumothorax and communicated fractures of the left acetabulum. According to the Letounel and Judet classification, T-shaped fracture involving posterior wall was diagnosed. A 3D printing pelvic model was established using CT digital imaging and communications in medicine (DICOM) data preoperatively, with which surgical procedures were simulated in preoperative surgery to confirm the sequence of the reduction and fixation as well as the position and length of the implants. Open reduction with internal fixation (ORIF) of the acetabular fracture using modified ilioinguinal and Kocher-Langenbeck approaches was performed 25 days after injury. Plates that had been pre-bent in the preoperative surgery were positioned and screws were tightened in the directions determined in the preoperative planning following satisfactory reduction. The duration of the operation was 170 min and blood loss was 900 mL. Postoperative X-rays showed that anatomical reduction of the acetabulum was achieved and the hip joint was congruous. The position and length of the implants were not different when compared with those in preoperative surgery on 3D printing models. We believe that preoperative surgery using 3D printing models is beneficial for confirming the reduction and fixation sequence, determining the reduction quality, shortening the operative time, minimizing preoperative difficulties, and predicting the prognosis for complicated fractures of acetabulam. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Antinociceptive efficacy of lacosamide in the monosodium iodoacetate rat model for osteoarthritis pain

PubMed Central

Beyreuther, Bettina; Callizot, Noëlle; Stöhr, Thomas

2007-01-01

The etiology of osteoarthritis is multifactorial, with inflammatory, metabolic, and mechanical causes. Pain in osteoarthritis is initiated by mild intra-articular inflammation and degeneration of articular cartilage and subchondral bone. The principle of treatment with acetaminophen or non-steroidal anti-inflammatory drugs is to reduce pain and improve joint function. Recently, animal models for osteoarthritic pain behavior have been established. The most frequently used rat model for analyzing properties of drugs on the pathology of osteoarthritis is the injection of the metabolic inhibitor monosodium iodoacetate into the joint, which inhibits the activity of glyceraldehyde-3-phosphate dehydrogenase in chondrocytes. Here, we characterize the effect on pain behavior of lacosamide, a member of a family of functionalized amino acids that are analogues of endogenous amino acids and D-serine, in the monosodium iodoacetate rat model for osteoarthritis in comparison to diclofenac and morphine. Lacosamide (3, 10, and 30 mg/kg) was able to reduce secondary mechanical allodynia and hyperalgesia similarly to morphine (3 mg/kg). In contrast, diclofenac (30 mg/kg) was only effective in reducing secondary mechanical hyperalgesia. During the first week, pain is induced mainly by inflammation in the iodoacetate model, but afterwards inflammation plays only a minor role in pain. Lacosamide was able to inhibit pain at days 3, 7 and 14 after induction of arthritis. This shows that lacosamide is able to reduce pain behavior induced by multiple mechanisms in animals. PMID:17284318

Design and Use of a 3D Prosthetic Leg in a Red-lored Amazon Parrot ( Amazona autumnalis).

PubMed

Galicia, Cecilia; Hernandez Urraca, Vanessa; Del Castillo, Luis; Mvz, Jaime Samour

2018-06-01

A three-dimensional (3D) prosthesis was designed and built for a red-lored Amazon parrot ( Amazona autumnalis) with a pre-existing amputation of the distal left leg at the tibiotarsal-tarsometatarsal joint and injuries to the right leg caused by cage companion aggression. The prosthesis consisted of a straight main imprint, with a round element at both ends to provide stability, and a bridge connecting this to a socket without a bottom where the stump could be accommodated and held securely with self-adhesive bandaging. Over a 4-month period, 3 different 3D prosthetic models were made and evaluated. The first model was fitted, but the parrot would only use the tip of the main imprint to stand and walk. The second model was designed with a semicircular imprint with only 1 round element at the cranial end, a different bridge to accommodate the change to the main imprint, and the same socket. With these changes, the parrot was able to place the imprint of the prosthesis on the floor to stand and move freely around its enclosure. To accommodate morphologic changes on the stump, a third model was created consisting of the same imprint and bridge, but the socket was cut vertically all the way on one side to allow distention on its diameter and provide a long-lasting fit to the stump over time.

A dual-phase microstructural approach to damage and fracture of Ti 3SiC 2/SiC joints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Ba Nghiep; Henager, Charles H.; Kurtz, Richard J.

We investigate the microcracking mechanisms responsible for Ti 3SiC 2/SiC joint damage observed at the macroscopic scale after neutron irradiation experiments in detail. A dual-phase microstructural approach to damage and fracture of Ti 3SiC 2/SiC joints is developed that uses a finely discretized two-phase domain based on a digital image of an actual microstructure involving embedded Ti 3SiC 2 and SiC phases. The behaviors of SiC and Ti 3SiC 2 in the domain are described by the continuum damage mechanics (CDM) model reported in Nguyen et al., J. Nucl. Mater., 2017, 495:504–515. This CDM model describes microcracking damage in brittlemore » ceramics caused by thermomechanical loading and irradiation-induced swelling. The dual-phase microstructural model is applied to predict the microcracking mechanisms occurring in a typical Ti 3SiC 2/SiC joint subjected to heating to 800 °C followed by irradiation-induced swelling at this temperature and cooling to room temperature after the applied swelling has reached the maximum swelling levels observed in the experiments for SiC and Ti 3SiC 2. The model predicts minor damage of the joint after heating but significant microcracking in the SiC phase and along the boundaries between SiC and Ti 3SiC 2 as well as along the bonding joint during irradiation-induced swelling and cooling to room temperature. Our predictions qualitatively agree with the limited experimental observations of joint damage at this irradiation temperature.« less

A dual-phase microstructural approach to damage and fracture of Ti 3SiC 2/SiC joints

DOE PAGES

Nguyen, Ba Nghiep; Henager, Charles H.; Kurtz, Richard J.

2017-12-05

We investigate the microcracking mechanisms responsible for Ti 3SiC 2/SiC joint damage observed at the macroscopic scale after neutron irradiation experiments in detail. A dual-phase microstructural approach to damage and fracture of Ti 3SiC 2/SiC joints is developed that uses a finely discretized two-phase domain based on a digital image of an actual microstructure involving embedded Ti 3SiC 2 and SiC phases. The behaviors of SiC and Ti 3SiC 2 in the domain are described by the continuum damage mechanics (CDM) model reported in Nguyen et al., J. Nucl. Mater., 2017, 495:504–515. This CDM model describes microcracking damage in brittlemore » ceramics caused by thermomechanical loading and irradiation-induced swelling. The dual-phase microstructural model is applied to predict the microcracking mechanisms occurring in a typical Ti 3SiC 2/SiC joint subjected to heating to 800 °C followed by irradiation-induced swelling at this temperature and cooling to room temperature after the applied swelling has reached the maximum swelling levels observed in the experiments for SiC and Ti 3SiC 2. The model predicts minor damage of the joint after heating but significant microcracking in the SiC phase and along the boundaries between SiC and Ti 3SiC 2 as well as along the bonding joint during irradiation-induced swelling and cooling to room temperature. Our predictions qualitatively agree with the limited experimental observations of joint damage at this irradiation temperature.« less

A concurrent computer aided detection (CAD) tool for articular cartilage disease of the knee on MR imaging using active shape models

NASA Astrophysics Data System (ADS)

Ramakrishna, Bharath; Saiprasad, Ganesh; Safdar, Nabile; Siddiqui, Khan; Chang, Chein-I.; Siegel, Eliot

2008-03-01

Osteoarthritis (OA) is the most common form of arthritis and a major cause of morbidity affecting millions of adults in the US and world wide. In the knee, OA begins with the degeneration of joint articular cartilage, eventually resulting in the femur and tibia coming in contact, and leading to severe pain and stiffness. There has been extensive research examining 3D MR imaging sequences and automatic/semi-automatic techniques for 2D/3D articular cartilage extraction. However, in routine clinical practice the most popular technique still remain radiographic examination and qualitative assessment of the joint space. This may be in large part because of a lack of tools that can provide clinically relevant diagnosis in adjunct (in near real time fashion) with the radiologist and which can serve the needs of the radiologists and reduce inter-observer variation. Our work aims to fill this void by developing a CAD application that can generate clinically relevant diagnosis of the articular cartilage damage in near real time fashion. The algorithm features a 2D Active Shape Model (ASM) for modeling the bone-cartilage interface on all the slices of a Double Echo Steady State (DESS) MR sequence, followed by measurement of the cartilage thickness from the surface of the bone, and finally by the identification of regions of abnormal thinness and focal/degenerative lesions. A preliminary evaluation of CAD tool was carried out on 10 cases taken from the Osteoarthritis Initiative (OAI) database. When compared with 2 board-certified musculoskeletal radiologists, the automatic CAD application was able to get segmentation/thickness maps in little over 60 seconds for all of the cases. This observation poses interesting possibilities for increasing radiologist productivity and confidence, improving patient outcomes, and applying more sophisticated CAD algorithms to routine orthopedic imaging tasks.

New evidence for the serpentinization of the Palaeozoic basement of southeastern Sicily from joint 3-D seismic velocity and attenuation tomography

NASA Astrophysics Data System (ADS)

Giampiccolo, E.; Brancato, A.; Manuella, F. C.; Carbone, S.; Gresta, S.; Scribano, V.

2017-12-01

In this study, we derived the first 3-D P-wave seismic attenuation images (QP) as well as new 3-D VP and VP/VS models for the crust in southeastern Sicily. We used a large data set of local seismic events occurring in the time span 1994-2013. The results of this tomographic study have important implications on the seismic behaviour of the region. Based on velocity and attenuation images, we identified distinct volumes characterized by different fluid content, which correlate well with seismicity distribution. Moreover, the obtained velocity and attenuation tomographies help us to provide a more complete picture of the crustal structure of the area. High VP, high QP and high VP/VS values have been obtained in the crustal basement, below a depth of 8 km, and may be interpreted as due to the presence of serpentinized peridotites. Accordingly, the new model for the degree of serpentinization, retrieved from VP values, shows that the basement has an average serpentinization value of 96 ± 3 vol.% at 8 km, decreasing to 44 ± 5 vol.% at about 18-20 km.

Customized Fabrication of Osteochondral Tissue for Articular Joint Surface Repair

DTIC Science & Technology

2016-09-01

differentiation cues for chondrogenesis and osteogenesis, by the 3D printing method of projection stereolithography (PSL). We further test the...military medical care costs. Post Traumatic Osteoarthritis, Injury, Articular Cartilage, tissue-engineered, 3D printing , Osteochondral constructs. Major...tissue with the stem cells used. He will also be assisting with the 3D printing of the material. Funding Support: Supported by internal University

4D computerized ionospheric tomography by using GPS measurements and IRI-Plas model

NASA Astrophysics Data System (ADS)

Tuna, Hakan; Arikan, Feza; Arikan, Orhan

2016-07-01

Ionospheric imaging is an important subject in ionospheric studies. GPS based TEC measurements provide very accurate information about the electron density values in the ionosphere. However, since the measurements are generally very sparse and non-uniformly distributed, computation of 3D electron density estimation from measurements alone is an ill-defined problem. Model based 3D electron density estimations provide physically feasible distributions. However, they are not generally compliant with the TEC measurements obtained from GPS receivers. In this study, GPS based TEC measurements and an ionosphere model known as International Reference Ionosphere Extended to Plasmasphere (IRI-Plas) are employed together in order to obtain a physically accurate 3D electron density distribution which is compliant with the real measurements obtained from a GPS satellite - receiver network. Ionospheric parameters input to the IRI-Plas model are perturbed in the region of interest by using parametric perturbation models such that the synthetic TEC measurements calculated from the resultant 3D electron density distribution fit to the real TEC measurements. The problem is considered as an optimization problem where the optimization parameters are the parameters of the parametric perturbation models. Proposed technique is applied over Turkey, on both calm and storm days of the ionosphere. Results show that the proposed technique produces 3D electron density distributions which are compliant with IRI-Plas model, GPS TEC measurements and ionosonde measurements. The effect of the GPS receiver station number on the performance of the proposed technique is investigated. Results showed that 7 GPS receiver stations in a region as large as Turkey is sufficient for both calm and storm days of the ionosphere. Since the ionization levels in the ionosphere are highly correlated in time, the proposed technique is extended to the time domain by applying Kalman based tracking and smoothing approaches onto the obtained results. Combining Kalman methods with the proposed 3D CIT technique creates a robust 4D ionospheric electron density estimation model, and has the advantage of decreasing the computational cost of the proposed method. Results applied on both calm and storm days of the ionosphere show that, new technique produces more robust solutions especially when the number of GPS receiver stations in the region is small. This study is supported by TUBITAK 114E541, 115E915 and Joint TUBITAK 114E092 and AS CR 14/001 projects.

Sacroiliac Joint Fusion Using Triangular Titanium Implants vs. Non-Surgical Management: Six-Month Outcomes from a Prospective Randomized Controlled Trial.

PubMed

Whang, Peter; Cher, Daniel; Polly, David; Frank, Clay; Lockstadt, Harry; Glaser, John; Limoni, Robert; Sembrano, Jonathan

2015-01-01

Sacroiliac (SI) joint pain is a prevalent, underdiagnosed cause of lower back pain. SI joint fusion can relieve pain and improve quality of life in patients who have failed nonoperative care. To date, no study has concurrently compared surgical and non-surgical treatments for chronic SI joint dysfunction. We conducted a prospective randomized controlled trial of 148 subjects with SI joint dysfunction due to degenerative sacroiliitis or sacroiliac joint disruptions who were assigned to either minimally invasive SI joint fusion with triangular titanium implants (N=102) or non-surgical management (NSM, n=46). SI joint pain scores, Oswestry Disability Index (ODI), Short-Form 36 (SF-36) and EuroQol-5D (EQ-5D) were collected at baseline and at 1, 3 and 6 months after treatment commencement. Six-month success rates, defined as the proportion of treated subjects with a 20-mm improvement in SI joint pain in the absence of severe device-related or neurologic SI joint-related adverse events or surgical revision, were compared using Bayesian methods. Subjects (mean age 51, 70% women) were highly debilitated at baseline (mean SI joint VAS pain score 82, mean ODI score 62). Six-month follow-up was obtained in 97.3%. By 6 months, success rates were 81.4% in the surgical group vs. 23.9% in the NSM group (difference of 56.6%, 95% posterior credible interval 41.4-70.0%, posterior probability of superiority >0.999). Clinically important (≥15 point) ODI improvement at 6 months occurred in 75% of surgery subjects vs. 27.3% of NSM subjects. At six months, quality of life improved more in the surgery group and satisfaction rates were high. The mean number of adverse events in the first six months was slightly higher in the surgical group compared to the non-surgical group (1.3 vs. 1.0 events per subject, p=0.1857). Six-month follow-up from this level 1 study showed that minimally invasive SI joint fusion using triangular titanium implants was more effective than non-surgical management in relieving pain, improving function and improving quality of life in patients with SI joint dysfunction due to degenerative sacroiliitis or SI joint disruptions. Minimally invasive SI joint fusion is an acceptable option for patients with chronic SI joint dysfunction due to degenerative sacroiliitis and sacroiliac joint disruptions unresponsive to non-surgical treatments.

Sacroiliac Joint Fusion Using Triangular Titanium Implants vs. Non-Surgical Management: Six-Month Outcomes from a Prospective Randomized Controlled Trial

PubMed Central

Whang, Peter; Polly, David; Frank, Clay; Lockstadt, Harry; Glaser, John; Limoni, Robert; Sembrano, Jonathan

2015-01-01

Background Sacroiliac (SI) joint pain is a prevalent, underdiagnosed cause of lower back pain. SI joint fusion can relieve pain and improve quality of life in patients who have failed nonoperative care. To date, no study has concurrently compared surgical and non-surgical treatments for chronic SI joint dysfunction. Methods We conducted a prospective randomized controlled trial of 148 subjects with SI joint dysfunction due to degenerative sacroiliitis or sacroiliac joint disruptions who were assigned to either minimally invasive SI joint fusion with triangular titanium implants (N=102) or non-surgical management (NSM, n=46). SI joint pain scores, Oswestry Disability Index (ODI), Short-Form 36 (SF-36) and EuroQol-5D (EQ-5D) were collected at baseline and at 1, 3 and 6 months after treatment commencement. Six-month success rates, defined as the proportion of treated subjects with a 20-mm improvement in SI joint pain in the absence of severe device-related or neurologic SI joint-related adverse events or surgical revision, were compared using Bayesian methods. Results Subjects (mean age 51, 70% women) were highly debilitated at baseline (mean SI joint VAS pain score 82, mean ODI score 62). Six-month follow-up was obtained in 97.3%. By 6 months, success rates were 81.4% in the surgical group vs. 23.9% in the NSM group (difference of 56.6%, 95% posterior credible interval 41.4-70.0%, posterior probability of superiority >0.999). Clinically important (≥15 point) ODI improvement at 6 months occurred in 75% of surgery subjects vs. 27.3% of NSM subjects. At six months, quality of life improved more in the surgery group and satisfaction rates were high. The mean number of adverse events in the first six months was slightly higher in the surgical group compared to the non-surgical group (1.3 vs. 1.0 events per subject, p=0.1857). Conclusions Six-month follow-up from this level 1 study showed that minimally invasive SI joint fusion using triangular titanium implants was more effective than non-surgical management in relieving pain, improving function and improving quality of life in patients with SI joint dysfunction due to degenerative sacroiliitis or SI joint disruptions. Clinical relevance Minimally invasive SI joint fusion is an acceptable option for patients with chronic SI joint dysfunction due to degenerative sacroiliitis and sacroiliac joint disruptions unresponsive to non-surgical treatments. PMID:25785242

Joint Publication 3-31. Command and Control for Joint Land Operations

DTIC Science & Technology

2010-06-29

task force] FALCON .” Admiral James Ellis, Commander, Joint Task Force NOBLE ANVIL during Operation ALLIED FORCE in letter correspondence to RAND...beneficial effect on the gr ound cam paign.” D uring t he ca mpaign, “ Army and M arine artillery were used interchangeably.” SOURCE: Lieutenant...consolidates, prioritizes, and forwards ultra -high frequency tactical satellite requirements to the JFC for channel allocation. k. Establishes, supervises

Detection of endoscopic looping during colonoscopy procedure by using embedded bending sensors

PubMed Central

Bruce, Michael; Choi, JungHun

2018-01-01

Background Looping of the colonoscope shaft during procedure is one of the most common obstacles encountered by colonoscopists. It occurs in 91% of cases with the N-sigmoid loop being the most common, occurring in 79% of cases. Purpose Herein, a novel system is developed that will give a complete three-dimensional (3D) vector image of the shaft as it passes through the colon, to aid the colonoscopist in detecting loops before they form. Patients and methods A series of connected links spans the middle 50% of the shaft, where loops are likely to form. Two potentiometers are attached at each joint to measure angular deflection in two directions to allow for 3D positioning. This 3D positioning is converted into a 3D vector image using computer software. MATLAB software has been used to display the image on a computer monitor. For the different configuration of the colon model, the system determined the looping status. Results Different configurations (N loop, reverse gamma loop, and reverse splenic flexure) of the loops were well defined using 3D vector image. Conclusion The novel sensory system can accurately define the various configuration of the colon during the colonoscopy procedure. PMID:29849469

Repeated administration of mazindol reduces spontaneous pain-related behaviors without modifying bone density and microarchitecture in a mouse model of complete Freund’s adjuvant-induced knee arthritis

PubMed Central

Robledo-González, LE; Martínez-Martínez, A; Vargas-Muñoz, VM; Acosta-González, RI; Plancarte-Sánchez, R; Anaya-Reyes, M; Fernández del Valle-Laisequilla, C; Reyes-García, JG; Jiménez-Andrade, JM

2017-01-01

Background The role of dopaminergic system in the development of rheumatoid arthritis-related pain, a major symptom in this disease, has not been explored. Therefore, the anti-nociceptive effect of mazindol, a dopamine uptake inhibitor, was evaluated in a model of complete Freund’s adjuvant (CFA)-induced arthritis. Furthermore, as studies have shown that the dopaminergic system regulates bone metabolism, the effect of mazindol on bone mass and microarchitecture was determined. Methods Adult ICR male mice received intra-articular injections of either CFA or saline into the right knee joint every week. Spontaneous pain-like behaviors (flinching and guarding) and locomotor activity were assessed at day 26 post-first CFA, following which, a single intraperitoneally (i.p.) administered dose of mazindol was given (1, 3 and 10 mg/kg). Then, the antinociceptive effect of a repeated administration of 3 mg/kg mazindol (daily, i.p.; day 15–day 26) was evaluated. Additionally, at day 26, the participation of D1-like, D2-like or opioid receptors in the antinociceptive effect of mazindol was evaluated. The effect of mazindol on bone density and microarchitecture was evaluated by micro-computed tomography. Results Acute administration of mazindol decreased the spontaneous pain-like behaviors in a dose-dependent manner without reducing the knee edema. However, mazindol at 10 mg/kg significantly increased the locomotor activity; therefore, 3 mg/kg mazindol was used for further studies. Repeated administration of 3 mg/kg mazindol significantly decreased the pain-like behaviors without modifying locomotor activity. The antinociceptive effect of mazindol was blocked by administration of a D2-like receptor antagonist (haloperidol), but not by administration of D1-like receptor antagonist (SCH 23390) or an opioid receptor antagonist (naloxone). Repeated administration of mazindol did not significantly modify the density and microarchitecture of periarticular bone of the arthritic and nonarthritic knee joints. Conclusion Results suggest that mazindol via D2-like receptors has an antinociceptive role in mice with CFA-induced knee arthritis without modifying the bone health negatively. PMID:28794657

Repeated administration of mazindol reduces spontaneous pain-related behaviors without modifying bone density and microarchitecture in a mouse model of complete Freund's adjuvant-induced knee arthritis.

PubMed

Robledo-González, L E; Martínez-Martínez, A; Vargas-Muñoz, V M; Acosta-González, R I; Plancarte-Sánchez, R; Anaya-Reyes, M; Fernández Del Valle-Laisequilla, C; Reyes-García, J G; Jiménez-Andrade, J M

2017-01-01

The role of dopaminergic system in the development of rheumatoid arthritis-related pain, a major symptom in this disease, has not been explored. Therefore, the anti-nociceptive effect of mazindol, a dopamine uptake inhibitor, was evaluated in a model of complete Freund's adjuvant (CFA)-induced arthritis. Furthermore, as studies have shown that the dopaminergic system regulates bone metabolism, the effect of mazindol on bone mass and microarchitecture was determined. Adult ICR male mice received intra-articular injections of either CFA or saline into the right knee joint every week. Spontaneous pain-like behaviors (flinching and guarding) and locomotor activity were assessed at day 26 post-first CFA, following which, a single intraperitoneally (i.p.) administered dose of mazindol was given (1, 3 and 10 mg/kg). Then, the antinociceptive effect of a repeated administration of 3 mg/kg mazindol (daily, i.p.; day 15-day 26) was evaluated. Additionally, at day 26, the participation of D1-like, D2-like or opioid receptors in the antinociceptive effect of mazindol was evaluated. The effect of mazindol on bone density and microarchitecture was evaluated by micro-computed tomography. Acute administration of mazindol decreased the spontaneous pain-like behaviors in a dose-dependent manner without reducing the knee edema. However, mazindol at 10 mg/kg significantly increased the locomotor activity; therefore, 3 mg/kg mazindol was used for further studies. Repeated administration of 3 mg/kg mazindol significantly decreased the pain-like behaviors without modifying locomotor activity. The antinociceptive effect of mazindol was blocked by administration of a D2-like receptor antagonist (haloperidol), but not by administration of D1-like receptor antagonist (SCH 23390) or an opioid receptor antagonist (naloxone). Repeated administration of mazindol did not significantly modify the density and microarchitecture of periarticular bone of the arthritic and nonarthritic knee joints. Results suggest that mazindol via D2-like receptors has an antinociceptive role in mice with CFA-induced knee arthritis without modifying the bone health negatively.

Bioinspired Robotic Fingers Based on Pneumatic Actuator and 3D Printing of Smart Material.

PubMed

Yang, Yang; Chen, Yonghua; Li, Yingtian; Chen, Michael Z Q; Wei, Ying

2017-06-01

In this article, we have proposed a novel robotic finger design principle aimed to address two challenges in soft pneumatic grippers-the controllability of the stiffness and the controllability of the bending position. The proposed finger design is composed of a 3D printed multimaterial substrate and a soft pneumatic actuator. The substrate has four polylactic acid (PLA) segments interlocked with three shape memory polymer (SMP) joints, inspired by bones and joints in human fingers. By controlling the thermal energy of an SMP joint, the stiffness of the joints is modulated due to the dramatic change in SMP elastic modulus around its glass transition temperature (T g ). When SMP joints are heated above T g , they exhibit very small stiffness, allowing the finger to easily bend around the SMP joints if the attached soft actuator is actuated. When there is no force from the soft actuator, shape recovery stress in SMP contributes to the finger's shape restoration. Since each joint's rotation can be individually controlled, the position control of the finger is made possible. Experimental analysis has been conducted to show the finger's variable stiffness and the result is compared with the analytical values. It is found that the stiffness ratio can be 24.9 times for a joint at room temperature (20°C) and at an elevated temperature of 60°C when air pressure p of the soft actuator is turned off. Finally, a gripper composed of two fingers is fabricated for demonstration.

A Digital Image-Based Discrete Fracture Network Model and Its Numerical Investigation of Direct Shear Tests

NASA Astrophysics Data System (ADS)

Wang, Peitao; Cai, Meifeng; Ren, Fenhua; Li, Changhong; Yang, Tianhong

2017-07-01

This paper develops a numerical approach to determine the mechanical behavior of discrete fractures network (DFN) models based on digital image processing technique and particle flow code (PFC2D). A series of direct shear tests of jointed rocks were numerically performed to study the effect of normal stress, friction coefficient and joint bond strength on the mechanical behavior of joint rock and evaluate the influence of micro-parameters on the shear properties of jointed rocks using the proposed approach. The complete shear stress-displacement curve of the DFN model under direct shear tests was presented to evaluate the failure processes of jointed rock. The results show that the peak and residual strength are sensitive to normal stress. A higher normal stress has a greater effect on the initiation and propagation of cracks. Additionally, an increase in the bond strength ratio results in an increase in the number of both shear and normal cracks. The friction coefficient was also found to have a significant influence on the shear strength and shear cracks. Increasing in the friction coefficient resulted in the decreasing in the initiation of normal cracks. The unique contribution of this paper is the proposed modeling technique to simulate the mechanical behavior of jointed rock mass based on particle mechanics approaches.

75 FR 81427 - Airworthiness Directives; The Boeing Company Model 747-200C, -200F, -400, -400D, and -400F Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-28

.... This AD results from a structural review of affected skin lap joints for widespread fatigue damage. We are issuing this AD to prevent fatigue cracking in certain lap joints, which could result in rapid... operation beyond 15,000 total flight cycles after doing the proposed modification. Boeing stated that...

pyGIMLi: An open-source library for modelling and inversion in geophysics

NASA Astrophysics Data System (ADS)

Rücker, Carsten; Günther, Thomas; Wagner, Florian M.

2017-12-01

Many tasks in applied geosciences cannot be solved by single measurements, but require the integration of geophysical, geotechnical and hydrological methods. Numerical simulation techniques are essential both for planning and interpretation, as well as for the process understanding of modern geophysical methods. These trends encourage open, simple, and modern software architectures aiming at a uniform interface for interdisciplinary and flexible modelling and inversion approaches. We present pyGIMLi (Python Library for Inversion and Modelling in Geophysics), an open-source framework that provides tools for modelling and inversion of various geophysical but also hydrological methods. The modelling component supplies discretization management and the numerical basis for finite-element and finite-volume solvers in 1D, 2D and 3D on arbitrarily structured meshes. The generalized inversion framework solves the minimization problem with a Gauss-Newton algorithm for any physical forward operator and provides opportunities for uncertainty and resolution analyses. More general requirements, such as flexible regularization strategies, time-lapse processing and different sorts of coupling individual methods are provided independently of the actual methods used. The usage of pyGIMLi is first demonstrated by solving the steady-state heat equation, followed by a demonstration of more complex capabilities for the combination of different geophysical data sets. A fully coupled hydrogeophysical inversion of electrical resistivity tomography (ERT) data of a simulated tracer experiment is presented that allows to directly reconstruct the underlying hydraulic conductivity distribution of the aquifer. Another example demonstrates the improvement of jointly inverting ERT and ultrasonic data with respect to saturation by a new approach that incorporates petrophysical relations in the inversion. Potential applications of the presented framework are manifold and include time-lapse, constrained, joint, and coupled inversions of various geophysical and hydrological data sets.

D-002 (beeswax alcohols): concurrent joint health benefits and gastroprotection.

PubMed

Molina, Vivian; Mas, R; Carbajal, D

2015-01-01

Nonsteroidal antiinflammatory drugs include the traditional drugs and more selective COX-2 inhibitors. Traditional nonsteroidal antiinflammatory drug use is hampered by their gastrotoxicity, while COX-2-inhibitors increase the cardiovascular risk. The search of safer substances for managing inflammatory conditions is updated, a challenge wherein dual COX/5-LOX inhibitors have a place. This review summarizes the benefits of D-002, a mixture of higher aliphatic beeswax alcohols, on joint health and gastric mucosa. D-002 elicits gastroprotection through a multiple mechanism that involves the increased secretion and improved quality of the gastric mucus, the reduction of hydroxyl radical, lipid peroxidation, protein oxidation, neutrophil infiltration and the increase of antioxidant enzymes on the gastric mucosa. Consistently, D-002 inhibits NSAIDs, ethanol, pylorus-ligation and acetic acid-induced gastric ulceration in rats, and has reduced gastrointestinal symptoms in clinical studies. Early results found that D-002 was effective in the cotton pellet-induced granuloma and carrageenan-induced pleurisy model in rats, lowering pleural leukotriene B4 levels without causing gastrointestinal ulceration. However, D-002 effects on inflammation received little attention for years. Recent data have shown that D-002 inhibited both COX and 5-LOX activities with a greater affinity for 5-LOX and could act as a dual COX/5-LOX inhibitor. This mechanism might explain efficacy in experimental inflammatory and osteoarthritic models as well as clinical efficacy in osteoarthritic patients while supporting the lack of D-002 gastrotoxicity, but not the gastroprotective effects, which appear to be due to multiple mechanisms. In summary oral D-002 intake could help manage inflammatory conditions that impair joint health, while offering gastroprotection.

Development and construction of a neutron beam line for accelerator-based boron neutron capture synovectomy.

PubMed

Gierga, D P; Yanch, J C; Shefer, R E

2000-01-01

A potential application of the 10B(n, alpha)7Li nuclear reaction for the treatment of rheumatoid arthritis, termed Boron Neutron Capture Synovectomy (BNCS), is under investigation. In an arthritic joint, the synovial lining becomes inflamed and is a source of great pain and discomfort for the afflicted patient. The goal of BNCS is to ablate the synovium, thereby eliminating the symptoms of the arthritis. A BNCS treatment would consist of an intra-articular injection of boron followed by neutron irradiation of the joint. Monte Carlo radiation transport calculations have been used to develop an accelerator-based epithermal neutron beam line for BNCS treatments. The model includes a moderator/reflector assembly, neutron producing target, target cooling system, and arthritic joint phantom. Single and parallel opposed beam irradiations have been modeled for the human knee, human finger, and rabbit knee joints. Additional reflectors, placed to the side and back of the joint, have been added to the model and have been shown to improve treatment times and skin doses by about a factor of 2. Several neutron-producing charged particle reactions have been examined for BNCS, including the 9Be(p,n) reaction at proton energies of 4 and 3.7 MeV, the 9Be(d,n) reaction at deuteron energies of 1.5 and 2.6 MeV, and the 7Li(p,n) reaction at a proton energy of 2.5 MeV. For an accelerator beam current of 1 mA and synovial boron uptake of 1000 ppm, the time to deliver a therapy dose of 10,000 RBEcGy ranges from 3 to 48 min, depending on the treated joint and the neutron producing charged particle reaction. The whole-body effective dose that a human would incur during a knee treatment has been estimated to be 3.6 rem or 0.75 rem, for 1000 ppm or 19,000 ppm synovial boron uptake, respectively, although the shielding configuration has not yet been optimized. The Monte Carlo design process culminated in the construction, installation, and testing of a dedicated BNCS beam line on the high-current tandem electrostatic accelerator at the Laboratory for Accelerator Beam Applications at the Massachusetts Institute of Technology.

Increasing Running Step Rate Reduces Patellofemoral Joint Forces

PubMed Central

Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

2013-01-01

Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

Long-range laser scanning and 3D imaging for the Gneiss quarries survey

NASA Astrophysics Data System (ADS)

Schenker, Filippo Luca; Spataro, Alessio; Pozzoni, Maurizio; Ambrosi, Christian; Cannata, Massimiliano; Günther, Felix; Corboud, Federico

2016-04-01

In Canton Ticino (Southern Switzerland), the exploitation of natural stone, mostly gneisses, is an important activity of valley's economies. Nowadays, these economic activities are menaced by (i) the exploitation costs related to geological phenomena such as fractures, faults and heterogeneous rocks that hinder the processing of the stone product, (ii) continuously changing demand because of the evolving natural stone fashion and (iii) increasing administrative limits and rules acting to protect the environment. Therefore, the sustainable development of the sector for the next decades needs new and effective strategies to regulate and plan the quarries. A fundamental step in this process is the building of a 3D geological model of the quarries to constrain the volume of commercial natural stone and the volume of waste. In this context, we conducted Terrestrial Laser Scanning surveys of the quarries in the Maggia Valley to obtain a detailed 3D topography onto which the geological units were mapped. The topographic 3D model was obtained with a long-range laser scanning Riegl VZ4000 that can measure from up to 4 km of distance with a speed of 147,000 points per second. It operates with the new V-line technology, which defines the surface relief by sensing differentiated signals (echoes), even in the presence of obstacles such as vegetation. Depending on the esthetics of the gneisses, we defined seven types of natural stones that, together with faults and joints, were mapped onto the 3D models of the exploitation sites. According to the orientation of the geological limits and structures, we projected the different rock units and fractures into the excavation front. This way, we obtained a 3D geological model from which we can quantitatively estimate the volume of the seven different natural stones (with different commercial value) and waste (with low commercial value). To verify the 3D geological models and to quantify exploited rock and waste volumes the same procedure will be repeated after ca. 6 months. Finally, these 3D geological models can be useful to (i) decrease the exploitation costs because they yield the extraction potential of quarry, (ii) become more efficient in the exploitation and more dynamic in the market because they permit better planning and (iii) decrease the waste by limiting the excavation in regions with low-quality rocks.

Reliability of four models for clinical gait analysis.

PubMed

Kainz, Hans; Graham, David; Edwards, Julie; Walsh, Henry P J; Maine, Sheanna; Boyd, Roslyn N; Lloyd, David G; Modenese, Luca; Carty, Christopher P

2017-05-01

Three-dimensional gait analysis (3DGA) has become a common clinical tool for treatment planning in children with cerebral palsy (CP). Many clinical gait laboratories use the conventional gait analysis model (e.g. Plug-in-Gait model), which uses Direct Kinematics (DK) for joint kinematic calculations, whereas, musculoskeletal models, mainly used for research, use Inverse Kinematics (IK). Musculoskeletal IK models have the advantage of enabling additional analyses which might improve the clinical decision-making in children with CP. Before any new model can be used in a clinical setting, its reliability has to be evaluated and compared to a commonly used clinical gait model (e.g. Plug-in-Gait model) which was the purpose of this study. Two testers performed 3DGA in eleven CP and seven typically developing participants on two occasions. Intra- and inter-tester standard deviations (SD) and standard error of measurement (SEM) were used to compare the reliability of two DK models (Plug-in-Gait and a six degrees-of-freedom model solved using Vicon software) and two IK models (two modifications of 'gait2392' solved using OpenSim). All models showed good reliability (mean SEM of 3.0° over all analysed models and joint angles). Variations in joint kinetics were less in typically developed than in CP participants. The modified 'gait2392' model which included all the joint rotations commonly reported in clinical 3DGA, showed reasonable reliable joint kinematic and kinetic estimates, and allows additional musculoskeletal analysis on surgically adjustable parameters, e.g. muscle-tendon lengths, and, therefore, is a suitable model for clinical gait analysis. Copyright © 2017. Published by Elsevier B.V.

Digital Holography and 3D Imaging: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America B.

PubMed

Banerjee, Partha P; Osten, Wolfgang; Picart, Pascal; Cao, Liangcai; Nehmetallah, George

2017-05-01

The OSA Topical Meeting on Digital Holography and 3D Imaging (DH) was held 25-28 July 2016 in Heidelberg, Germany, as part of the Imaging Congress. Feature issues based on the DH meeting series have been released by Applied Optics (AO) since 2007. This year, AO and the Journal of the Optical Society of America B (JOSA B) jointly decided to have one such feature issue in each journal. This feature issue includes 31 papers in AO and 11 in JOSA B, and covers a large range of topics, reflecting the rapidly expanding techniques and applications of digital holography and 3D imaging. The upcoming DH meeting (DH 2017) will be held from 29 May to 1 June in Jeju Island, South Korea.

Joint segmentation of lumen and outer wall from femoral artery MR images: Towards 3D imaging measurements of peripheral arterial disease.

PubMed

Ukwatta, Eranga; Yuan, Jing; Qiu, Wu; Rajchl, Martin; Chiu, Bernard; Fenster, Aaron

2015-12-01

Three-dimensional (3D) measurements of peripheral arterial disease (PAD) plaque burden extracted from fast black-blood magnetic resonance (MR) images have shown to be more predictive of clinical outcomes than PAD stenosis measurements. To this end, accurate segmentation of the femoral artery lumen and outer wall is required for generating volumetric measurements of PAD plaque burden. Here, we propose a semi-automated algorithm to jointly segment the femoral artery lumen and outer wall surfaces from 3D black-blood MR images, which are reoriented and reconstructed along the medial axis of the femoral artery to obtain improved spatial coherence between slices of the long, thin femoral artery and to reduce computation time. The developed segmentation algorithm enforces two priors in a global optimization manner: the spatial consistency between the adjacent 2D slices and the anatomical region order between the femoral artery lumen and outer wall surfaces. The formulated combinatorial optimization problem for segmentation is solved globally and exactly by means of convex relaxation using a coupled continuous max-flow (CCMF) model, which is a dual formulation to the convex relaxed optimization problem. In addition, the CCMF model directly derives an efficient duality-based algorithm based on the modern multiplier augmented optimization scheme, which has been implemented on a GPU for fast computation. The computed segmentations from the developed algorithm were compared to manual delineations from experts using 20 black-blood MR images. The developed algorithm yielded both high accuracy (Dice similarity coefficients ≥ 87% for both the lumen and outer wall surfaces) and high reproducibility (intra-class correlation coefficient of 0.95 for generating vessel wall area), while outperforming the state-of-the-art method in terms of computational time by a factor of ≈ 20. Copyright © 2015 Elsevier B.V. All rights reserved.

Mandibular kinematics represented by a non-orthogonal floating axis joint coordinate system.

PubMed

Leader, Joseph K; Boston, J Robert; Debski, Richard E; Rudy, Thomas E

2003-02-01

There are many methods used to represent joint kinematics (e.g., roll, pitch, and yaw angles; instantaneous center of rotation; kinematic center; helical axis). Often in biomechanics internal landmarks are inferred from external landmarks. This study represents mandibular kinematics using a non-orthogonal floating axis joint coordinate system based on 3-D geometric models with parameters that are "clinician friendly" and mathematically rigorous. Kinematics data for two controls were acquired from passive fiducial markers attached to a custom dental clutch. The geometric models were constructed from MRI data. The superior point along the arc of the long axis of the condyle was used to define the coordinate axes. The kinematic data and geometric models were registered through fiducial markers visible during both protocols. The mean absolute maxima across the subjects for sagittal rotation, coronal rotation, axial rotation, medial-lateral translation, anterior-posterior translation, and inferior-superior translation were 34.10 degrees, 1.82 degrees, 1.14 degrees, 2.31, 21.07, and 6.95 mm, respectively. All the parameters, except for one subject's axial rotation, were reproducible across two motion recording sessions. There was a linear correlation between sagittal rotation and translation, the dominant motion plane, with approximately 1.5 degrees of rotation per millimeter of translation. The novel approach of combining the floating axis system with geometric models succinctly described mandibular kinematics with reproducible and clinician friendly parameters.

Hand pose estimation in depth image using CNN and random forest

NASA Astrophysics Data System (ADS)

Chen, Xi; Cao, Zhiguo; Xiao, Yang; Fang, Zhiwen

2018-03-01

Thanks to the availability of low cost depth cameras, like Microsoft Kinect, 3D hand pose estimation attracted special research attention in these years. Due to the large variations in hand`s viewpoint and the high dimension of hand motion, 3D hand pose estimation is still challenging. In this paper we propose a two-stage framework which joint with CNN and Random Forest to boost the performance of hand pose estimation. First, we use a standard Convolutional Neural Network (CNN) to regress the hand joints` locations. Second, using a Random Forest to refine the joints from the first stage. In the second stage, we propose a pyramid feature which merges the information flow of the CNN. Specifically, we get the rough joints` location from first stage, then rotate the convolutional feature maps (and image). After this, for each joint, we map its location to each feature map (and image) firstly, then crop features at each feature map (and image) around its location, put extracted features to Random Forest to refine at last. Experimentally, we evaluate our proposed method on ICVL dataset and get the mean error about 11mm, our method is also real-time on a desktop.

Near-field non-radial motion generation from underground chemical explosions in jointed granite

DOE PAGES

Vorobiev, Oleg; Ezzedine, Souheil; Hurley, Ryan

2017-09-22

Here, this paper describes analysis of non-radial ground motion generated by chemical explosions in a jointed rock formation during the Source Physics Experiment (SPE). Such motion makes it difficult to discriminate between various subsurface events such as explosions, implosions (i.e. mine collapse) and earthquakes. We apply 3-D numerical simulations to understand experimental data collected during the SPEs. The joints are modelled explicitly as compliant thin inclusions embedded into the rock mass. Mechanical properties of the rock and the joints as well as the joint spacing and orientation are inferred from experimental test data, and geophysical and geological characterization of themore » SPE site which is dominantly Climax Stock granitic outcrop. The role of various factors characterizing the joints such as joint spacing, frictional properties, orientation and persistence in generation of non-radial motion is addressed. The joints in granite at the SPE site are oriented in nearly orthogonal directions with two vertical sets dipping at 70–80 degrees with the same strike angle, one vertical set almost orthogonal to the first two and one shallow angle joint set dipping 15 degrees. In this study we establish the relationship between the joint orientation and azimuthal variations in the polarity of the observed shear motion. The majority of the shear motion is generated due to the effects of non-elastic sliding on the joints near the source, where the wave can create significant shear stress to overcome the cohesive forces at the joints. Near the surface the joints are less confined and are subject to sliding when the pressure waves are reflected. In the far field, where the cohesive forces on the joints cannot be overcome, additional shear motion can be generated due to elastic anisotropy of the rock mass given by preferred spatial orientations of compliant joints.« less

Near-field non-radial motion generation from underground chemical explosions in jointed granite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vorobiev, Oleg; Ezzedine, Souheil; Hurley, Ryan

Here, this paper describes analysis of non-radial ground motion generated by chemical explosions in a jointed rock formation during the Source Physics Experiment (SPE). Such motion makes it difficult to discriminate between various subsurface events such as explosions, implosions (i.e. mine collapse) and earthquakes. We apply 3-D numerical simulations to understand experimental data collected during the SPEs. The joints are modelled explicitly as compliant thin inclusions embedded into the rock mass. Mechanical properties of the rock and the joints as well as the joint spacing and orientation are inferred from experimental test data, and geophysical and geological characterization of themore » SPE site which is dominantly Climax Stock granitic outcrop. The role of various factors characterizing the joints such as joint spacing, frictional properties, orientation and persistence in generation of non-radial motion is addressed. The joints in granite at the SPE site are oriented in nearly orthogonal directions with two vertical sets dipping at 70–80 degrees with the same strike angle, one vertical set almost orthogonal to the first two and one shallow angle joint set dipping 15 degrees. In this study we establish the relationship between the joint orientation and azimuthal variations in the polarity of the observed shear motion. The majority of the shear motion is generated due to the effects of non-elastic sliding on the joints near the source, where the wave can create significant shear stress to overcome the cohesive forces at the joints. Near the surface the joints are less confined and are subject to sliding when the pressure waves are reflected. In the far field, where the cohesive forces on the joints cannot be overcome, additional shear motion can be generated due to elastic anisotropy of the rock mass given by preferred spatial orientations of compliant joints.« less

3D Optical Investigation of 2 Nail Systems Used in Tibiotalocalcaneal Arthrodesis: A Biomechanical Study.

PubMed

Evers, Julia; Lakemeier, Martin; Wähnert, Dirk; Schulze, Martin; Richter, Martinus; Raschke, Michael J; Ochman, Sabine

2017-05-01

Although retrograde intramedullary nails for tibiotalocalcaneal arthrodesis (TTCA) are an established fixation method, few studies have evaluated the stability of the available nail systems. The purpose of this study was to compare biomechanically the primary stability of 2 nail-systems, A3 (Small Bone Innovations) and HAN (Synthes), in human cadavers and analyze the exact point of instability in TTCA by means of optical measurement. In 6 pairs of lower legs (n = 12) of fresh-frozen human cadavers with osteoporotic bone structure, bone mineral density (BMD) was determined. Pairwise randomized implantation of either an HAN or A3 nail was executed. Performance and stability were measured by quasi-static tests using 3D motion tracking (NDI Optotrak-Certus) followed by cyclic loading tests during dorsi- and plantarflexion. 3D optical analysis in quasi-static tests showed a significantly lower degree of movement for the HAN nail in rotational and dorsi-/plantarflexion, especially in the subtalar joint. Cyclic loading tests were consistent with quasi-static tests. The A3 nail offered lower stability during axial torsion in the ankle and subtalar joints and during plantar- and dorsiflexion in the subtalar joint in osteoporotic bones. This study was the first to examine the primary stability of different arthrodesis nails in TTCA and their bony parts with a 3D motion analysis. The better stability of the locking-only HAN nail in this osteoporotic test setup could lead to more favorable results in comparison to the A3 nail in clinical use.

Error Modeling and Experimental Study of a Flexible Joint 6-UPUR Parallel Six-Axis Force Sensor.

PubMed

Zhao, Yanzhi; Cao, Yachao; Zhang, Caifeng; Zhang, Dan; Zhang, Jie

2017-09-29

By combining a parallel mechanism with integrated flexible joints, a large measurement range and high accuracy sensor is realized. However, the main errors of the sensor involve not only assembly errors, but also deformation errors of its flexible leg. Based on a flexible joint 6-UPUR (a kind of mechanism configuration where U-universal joint, P-prismatic joint, R-revolute joint) parallel six-axis force sensor developed during the prephase, assembly and deformation error modeling and analysis of the resulting sensors with a large measurement range and high accuracy are made in this paper. First, an assembly error model is established based on the imaginary kinematic joint method and the Denavit-Hartenberg (D-H) method. Next, a stiffness model is built to solve the stiffness matrix. The deformation error model of the sensor is obtained. Then, the first order kinematic influence coefficient matrix when the synthetic error is taken into account is solved. Finally, measurement and calibration experiments of the sensor composed of the hardware and software system are performed. Forced deformation of the force-measuring platform is detected by using laser interferometry and analyzed to verify the correctness of the synthetic error model. In addition, the first order kinematic influence coefficient matrix in actual circumstances is calculated. By comparing the condition numbers and square norms of the coefficient matrices, the conclusion is drawn theoretically that it is very important to take into account the synthetic error for design stage of the sensor and helpful to improve performance of the sensor in order to meet needs of actual working environments.

Error Modeling and Experimental Study of a Flexible Joint 6-UPUR Parallel Six-Axis Force Sensor

PubMed Central

Zhao, Yanzhi; Cao, Yachao; Zhang, Caifeng; Zhang, Dan; Zhang, Jie

2017-01-01

By combining a parallel mechanism with integrated flexible joints, a large measurement range and high accuracy sensor is realized. However, the main errors of the sensor involve not only assembly errors, but also deformation errors of its flexible leg. Based on a flexible joint 6-UPUR (a kind of mechanism configuration where U-universal joint, P-prismatic joint, R-revolute joint) parallel six-axis force sensor developed during the prephase, assembly and deformation error modeling and analysis of the resulting sensors with a large measurement range and high accuracy are made in this paper. First, an assembly error model is established based on the imaginary kinematic joint method and the Denavit-Hartenberg (D-H) method. Next, a stiffness model is built to solve the stiffness matrix. The deformation error model of the sensor is obtained. Then, the first order kinematic influence coefficient matrix when the synthetic error is taken into account is solved. Finally, measurement and calibration experiments of the sensor composed of the hardware and software system are performed. Forced deformation of the force-measuring platform is detected by using laser interferometry and analyzed to verify the correctness of the synthetic error model. In addition, the first order kinematic influence coefficient matrix in actual circumstances is calculated. By comparing the condition numbers and square norms of the coefficient matrices, the conclusion is drawn theoretically that it is very important to take into account the synthetic error for design stage of the sensor and helpful to improve performance of the sensor in order to meet needs of actual working environments. PMID:28961209

CAIPIRINHA accelerated SPACE enables 10-min isotropic 3D TSE MRI of the ankle for optimized visualization of curved and oblique ligaments and tendons.

PubMed

Kalia, Vivek; Fritz, Benjamin; Johnson, Rory; Gilson, Wesley D; Raithel, Esther; Fritz, Jan

2017-09-01

To test the hypothesis that a fourfold CAIPIRINHA accelerated, 10-min, high-resolution, isotropic 3D TSE MRI prototype protocol of the ankle derives equal or better quality than a 20-min 2D TSE standard protocol. Following internal review board approval and informed consent, 3-Tesla MRI of the ankle was obtained in 24 asymptomatic subjects including 10-min 3D CAIPIRINHA SPACE TSE prototype and 20-min 2D TSE standard protocols. Outcome variables included image quality and visibility of anatomical structures using 5-point Likert scales. Non-parametric statistical testing was used. P values ≤0.001 were considered significant. Edge sharpness, contrast resolution, uniformity, noise, fat suppression and magic angle effects were without statistical difference on 2D and 3D TSE images (p > 0.035). Fluid was mildly brighter on intermediate-weighted 2D images (p < 0.001), whereas 3D images had substantially less partial volume, chemical shift and no pulsatile-flow artifacts (p < 0.001). Oblique and curved planar 3D images resulted in mildly-to-substantially improved visualization of joints, spring, bifurcate, syndesmotic, collateral and sinus tarsi ligaments, and tendons (p < 0.001, respectively). 3D TSE MRI with CAIPIRINHA acceleration enables high-spatial resolution oblique and curved planar MRI of the ankle and visualization of ligaments, tendons and joints equally well or better than a more time-consuming anisotropic 2D TSE MRI. • High-resolution 3D TSE MRI improves visualization of ankle structures. • Limitations of current 3D TSE MRI include long scan times. • 3D CAIPIRINHA SPACE allows now a fourfold-accelerated data acquisition. • 3D CAIPIRINHA SPACE enables high-spatial-resolution ankle MRI within 10 min. • 10-min 3D CAIPIRINHA SPACE produces equal-or-better quality than 20-min 2D TSE.

Development and validation of a German version of the joint protection behavior assessment in patients with rheumatoid arthritis.

PubMed

Niedermann, K; Forster, A; Hammond, A; Uebelhart, D; de Bie, R

2007-03-15

Joint protection (JP) is an important part of the treatment concept for patients with rheumatoid arthritis (RA). The Joint Protection Behavior Assessment short form (JPBA-S) assesses the use of hand JP methods by patients with RA while preparing a hot drink. The purpose of this study was to develop a German version of the JPBA-S (D-JPBA-S) and to test its validity and reliability. A manual was developed through consensus with 8 occupational therapist (OT) experts as the reference for assessing patients' JP behavior. Twenty-four patients with RA and 10 healthy individuals were videotaped while performing 10 tasks reflecting the activity of preparing instant coffee. Recordings were repeated after 3 months for test-retest analysis. One rater assessed all available patient recordings (n = 23, recorded twice) for test-retest reliability. The video recordings of 10 randomly selected patients and all healthy individuals were independently assessed for interrater reliability by 6 OTs who were explicitly asked to follow the manual. Rasch analysis was performed to test construct validity and transform ordinal raw data into interval data for reliability calculations. Nine of the 10 tasks fit the Rasch model. The D-JPBA-S, consisting of 9 valid tasks, had an intraclass correlation coefficient of 0.77 for interrater reliability and 0.71 for test-retest reliability. The D-JPBA-S provides a valid and reliable instrument for assessing JP behavior of patients with RA and can be used in German-speaking countries.

Field Quality Study of a 1-m-Long Single-Aperture 11-T Nb$$_3$$Sn Dipole Model for LHC Upgrades

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chlachidze, G.; DiMarco, J.; Andreev, N.

2014-01-01

FNAL and CERN are carrying out a joint R&D program with the goal of building a 5.5-m-long twin-aperture 11-T Nb_3Sn dipole prototype that is suitable for installation in the LHC. An important part of the program is the development and test of a series of short single-aperture and twin-aperture dipole models with a nominal field of 11 T at the LHC operation current of 11.85 kA and 20% margin. This paper presents the results of magnetic measurements of a 1-m-long single-aperture Nb_3Sn dipole model fabricated and tested recently at FNAL, including geometrical field harmonics and effects of coil magnetization andmore » iron yoke saturation.« less

Evaluation of a subject-specific, torque-driven computer simulation model of one-handed tennis backhand groundstrokes.

PubMed

Kentel, Behzat B; King, Mark A; Mitchell, Sean R

2011-11-01

A torque-driven, subject-specific 3-D computer simulation model of the impact phase of one-handed tennis backhand strokes was evaluated by comparing performance and simulation results. Backhand strokes of an elite subject were recorded on an artificial tennis court. Over the 50-ms period after impact, good agreement was found with an overall RMS difference of 3.3° between matching simulation and performance in terms of joint and racket angles. Consistent with previous experimental research, the evaluation process showed that grip tightness and ball impact location are important factors that affect postimpact racket and arm kinematics. Associated with these factors, the model can be used for a better understanding of the eccentric contraction of the wrist extensors during one-handed backhand ground strokes, a hypothesized mechanism of tennis elbow.

Crashworthiness analysis using advanced material models in DYNA3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Logan, R.W.; Burger, M.J.; McMichael, L.D.

1993-10-22

As part of an electric vehicle consortium, LLNL and Kaiser Aluminum are conducting experimental and numerical studies on crashworthy aluminum spaceframe designs. They have jointly explored the effect of heat treat on crush behavior and duplicated the experimental behavior with finite-element simulations. The major technical contributions to the state of the art in numerical simulation arise from the development and use of advanced material model descriptions for LLNL`s DYNA3D code. Constitutive model enhancements in both flow and failure have been employed for conventional materials such as low-carbon steels, and also for lighter weight materials such as aluminum and fiber compositesmore » being considered for future vehicles. The constitutive model enhancements are developed as extensions from LLNL`s work in anisotropic flow and multiaxial failure modeling. Analysis quality as a function of level of simplification of material behavior and mesh is explored, as well as the penalty in computation cost that must be paid for using more complex models and meshes. The lightweight material modeling technology is being used at the vehicle component level to explore the safety implications of small neighborhood electric vehicles manufactured almost exclusively from these materials.« less

Depth-color fusion strategy for 3-D scene modeling with Kinect.

PubMed

Camplani, Massimo; Mantecon, Tomas; Salgado, Luis

2013-12-01

Low-cost depth cameras, such as Microsoft Kinect, have completely changed the world of human-computer interaction through controller-free gaming applications. Depth data provided by the Kinect sensor presents several noise-related problems that have to be tackled to improve the accuracy of the depth data, thus obtaining more reliable game control platforms and broadening its applicability. In this paper, we present a depth-color fusion strategy for 3-D modeling of indoor scenes with Kinect. Accurate depth and color models of the background elements are iteratively built, and used to detect moving objects in the scene. Kinect depth data is processed with an innovative adaptive joint-bilateral filter that efficiently combines depth and color by analyzing an edge-uncertainty map and the detected foreground regions. Results show that the proposed approach efficiently tackles main Kinect data problems: distance-dependent depth maps, spatial noise, and temporal random fluctuations are dramatically reduced; objects depth boundaries are refined, and nonmeasured depth pixels are interpolated. Moreover, a robust depth and color background model and accurate moving objects silhouette are generated.

Undercooling Behavior and Intermetallic Compound Coalescence in Microscale Sn-3.0Ag-0.5Cu Solder Balls and Sn-3.0Ag-0.5Cu/Cu Joints

NASA Astrophysics Data System (ADS)

Zhou, M. B.; Ma, X.; Zhang, X. P.

2012-11-01

The microstructure of microscale solder interconnects and soldering defects have long been known to have a significant influence on the reliability of electronic packaging, and both are directly related to the solidification behavior of the undercooled solder. In this study, the undercooling behavior and solidification microstructural evolution of Sn-3.0Ag-0.5Cu solder balls with different diameters (0.76 mm, 0.50 mm, and 0.30 mm) and the joints formed by soldering these balls on Cu open pads of two diameters (0.48 mm and 0.32 mm) on a printed circuit board (PCB) substrate were characterized by differential scanning calorimetry (DSC) incorporated into the reflow process. Results show that the decrease in diameter of the solder balls leads to an obvious increase in the undercooling of the balls, while the undercooling of the solder joints shows a dependence on both the diameter of the solder balls and the diameter ratio of solder ball to Cu pad (i.e., D s/ D p), and the diameter of the solder balls has a stronger influence on the undercooling of the joints than the dimension of the Cu pad. Coarse primary intermetallic compound (IMC) solidification phases were formed in the smaller solder balls and joints. The bulk Ag3Sn IMC is the primary solidification phase in the as-reflowed solder balls. Due to the interfacial reaction and dissolution of Cu atoms into the solder matrix, the primary Ag3Sn phase can be suppressed and the bulk Cu6Sn5 IMC is the only primary solidification phase in the as-reflowed solder joints.

3D Vp heterogeneity beneath the Marmara Sea: Shot tomography on a 2D OBS array

NASA Astrophysics Data System (ADS)

Bayrakci, Gaye; Laigle, Mireille; Bécel, Anne; Hirn, Alfred; Taymaz, Tuncay; Yolsal-Ćevikbilen, Seda

2010-05-01

After the 1999 Izmit and Duzce earthquakes, the multi-method SEISMARMARA seismic survey has been carried out with the aim to constrain the seismogenic part of the North Anatolian Fault (NAF) immersed into the Marmara Sea. During this survey, a network of 35 3-components Japanese Ocean Bottom Seismometers (OBS) placed on a 2D grid and land stations have recorded the current seismic activity for a period of 6 weeks and 2000 km of MCS profiles shot in the North Marmara Trough (NMT). In the present study the first arrival times of artificial sources are inverted with the well known local earthquake tomography (LET) code Simulps in order to approach the 3D upper-crustal heterogeneity which then could be implemented as initial model easily and without any loss of information into a joint inversion of the local earthquake data and shots. The 3D upper-crustal P-wave velocity heterogeneity of the North Marmara Trough (NMT) is derived by inverting a set of 16000 first arrival times of artificial sources. We have checked the sensitivity of the results to the grid geometry, the control parameters and the 1D initial velocity model. Due to a huge basement depth variation between the NMT rims and the trough itself, we have then designed a 3D a priori model by taking into account the sea-floor depth and the topographic trend of the basement. This 3D initial model allowed to include the shots recorded by 5 land stations into the inverted data set and to improve the image resolution at the borders of NMT. It allowed also to have a denser inversion grid which is needed for constraining the small wave-length heterogeneity of the Marmara Sea. The artefacts which may be due to the very large perturbations with respect to the 1D initial model were avoided with the use of this 3D initial model. The reliability of the results are validated by synthetic tests and by the comparison with the seismic reflection and refraction profiles which principal characteristics such as the sedimentary infill and basement geometry are remarkably recovered by the inversion in the well resolved regions. This study provides an unprecedented 3D view of the sedimentary thicknesses and of the basement topography which shows large vertical throws which may reach up to 7 km. It reveals also the variations of more than 2 km of the basement topography in a distance of 5 km along the sea-bottom trace of the North Anatolian Fault and its basins. The consideration of the 3D sedimentary thickness and of such basement topography is crucial for accurate relocation of the earthquakes by taking into account the 3D heterogeneity of both, upper-crustal P and S wave velocities. This 3D structure may find also further applications like in modeling studies for the evolution and the present activity of the Marmara Sea's features.

Joint Machine Learning and Game Theory for Rate Control in High Efficiency Video Coding.

PubMed

Gao, Wei; Kwong, Sam; Jia, Yuheng

2017-08-25

In this paper, a joint machine learning and game theory modeling (MLGT) framework is proposed for inter frame coding tree unit (CTU) level bit allocation and rate control (RC) optimization in High Efficiency Video Coding (HEVC). First, a support vector machine (SVM) based multi-classification scheme is proposed to improve the prediction accuracy of CTU-level Rate-Distortion (R-D) model. The legacy "chicken-and-egg" dilemma in video coding is proposed to be overcome by the learning-based R-D model. Second, a mixed R-D model based cooperative bargaining game theory is proposed for bit allocation optimization, where the convexity of the mixed R-D model based utility function is proved, and Nash bargaining solution (NBS) is achieved by the proposed iterative solution search method. The minimum utility is adjusted by the reference coding distortion and frame-level Quantization parameter (QP) change. Lastly, intra frame QP and inter frame adaptive bit ratios are adjusted to make inter frames have more bit resources to maintain smooth quality and bit consumption in the bargaining game optimization. Experimental results demonstrate that the proposed MLGT based RC method can achieve much better R-D performances, quality smoothness, bit rate accuracy, buffer control results and subjective visual quality than the other state-of-the-art one-pass RC methods, and the achieved R-D performances are very close to the performance limits from the FixedQP method.

Rescuing Joint Personnel Recovery: Using Air Force Capability to Address Joint Shortfalls

DTIC Science & Technology

2011-06-01

of an IP, the IP is not successfully reintegrated or the lessons learned are not incorporated into other operations. Adversaries will benefit from...Washington, D.C.: Office of Air Force History , United States Air Force, 1980, 117. 47 Durant , Michael J. In the Company of Heroes, Penguin Group... Lessons Learned, 22 September 2005, 3. 2 US Joint Task Force Katrina. The Federal Response to Hurricane Katrina Lessons Learned, February 2006, 54

Mapping soil salinity and a fresh-water intrusion in three-dimensions using a quasi-3d joint-inversion of DUALEM-421S and EM34 data

NASA Astrophysics Data System (ADS)

Zare, Ehsan; Huang, Jingyi; Koganti, Triven; Triantafilis, John

2017-04-01

In order to understand the drivers of topsoil salinization, the distribution and movement of salt in accordance with groundwater need mapping. In this study, we described a method to map the distribution of soil salinity, as measured by the electrical conductivity of a saturated soil-paste extract (ECe), and in 3-dimensions around a water storage reservoir in an irrigated field near Bourke, New South Wales, Australia. A quasi-3d electromagnetic conductivity image (EMCI) or model of the true electrical conductivity (sigma) was developed using 133 apparent electrical conductivity (ECa) measurements collected on a 50 m grid and using various coil arrays of DUALEM-421S and EM34 instruments. For the DUALEM-421S we considered ECa in horizontal coplanar (i.e., 1 mPcon, 2 mPcon and 4 mPcon) and vertical coplanar (i.e., 1 mHcon, 2 mHcon and 4 mHcon) arrays. For the EM34, three measurements in the horizontal mode (i.e., EM34-10H, EM34-20H and EM34-40H) were considered. We estimated σ using a quasi-3d joint-inversion algorithm (EM4Soil). The best correlation (R2 = 0.92) between σ and measured soil ECe was identified when a forward modelling (FS), inversion algorithm (S2) and damping factor (lambda = 0.2) were used and using both DUALEM-421 and EM34 data; but not including the 4 m coil arrays of the DUALEM-421S. A linear regression calibration model was used to predict ECe in 3-dimensions beneath the study field. The predicted ECe was consistent with previous studies and revealed the distribution of ECe and helped to infer a freshwater intrusion from a water storage reservoir at depth and as a function of its proximity to near-surface prior stream channels and buried paleochannels. It was concluded that this method can be applied elsewhere to map the soil salinity and water movement and provide guidance for improved land management.|

Mapping soil salinity and a fresh-water intrusion in three-dimensions using a quasi-3d joint-inversion of DUALEM-421S and EM34 data.

PubMed

Huang, J; Koganti, T; Santos, F A Monteiro; Triantafilis, J

2017-01-15

In order to understand the drivers of topsoil salinization, the distribution and movement of salt in accordance with groundwater need mapping. In this study, we described a method to map the distribution of soil salinity, as measured by the electrical conductivity of a saturated soil-paste extract (EC e ), and in 3-dimensions around a water storage reservoir in an irrigated field near Bourke, New South Wales, Australia. A quasi-3d electromagnetic conductivity image (EMCI) or model of the true electrical conductivity (σ) was developed using 133 apparent electrical conductivity (EC a ) measurements collected on a 50m grid and using various coil arrays of DUALEM-421S and EM34 instruments. For the DUALEM-421S we considered EC a in horizontal coplanar (i.e., 1mPcon, 2mPcon and 4mPcon) and vertical coplanar (i.e., 1mHcon, 2mHcon and 4mHcon) arrays. For the EM34, three measurements in the horizontal mode (i.e., EM34-10H, EM34-20H and EM34-40H) were considered. We estimated σ using a quasi-3d joint-inversion algorithm (EM4Soil). The best correlation (R 2 =0.92) between σ and measured soil EC e was identified when a forward modelling (FS), inversion algorithm (S2) and damping factor (λ=0.2) were used and using both DUALEM-421 and EM34 data; but not including the 4m coil arrays of the DUALEM-421S. A linear regression calibration model was used to predict EC e in 3-dimensions beneath the study field. The predicted EC e was consistent with previous studies and revealed the distribution of EC e and helped to infer a freshwater intrusion from a water storage reservoir at depth and as a function of its proximity to near-surface prior stream channels and buried paleochannels. It was concluded that this method can be applied elsewhere to map the soil salinity and water movement and provide guidance for improved land management. Copyright © 2016 Elsevier B.V. All rights reserved.

Selection of optimal multispectral imaging system parameters for small joint arthritis detection

NASA Astrophysics Data System (ADS)

Dolenec, Rok; Laistler, Elmar; Stergar, Jost; Milanic, Matija

2018-02-01

Early detection and treatment of arthritis is essential for a successful outcome of the treatment, but it has proven to be very challenging with existing diagnostic methods. Novel methods based on the optical imaging of the affected joints are becoming an attractive alternative. A non-contact multispectral imaging (MSI) system for imaging of small joints of human hands and feet is being developed. In this work, a numerical simulation of the MSI system is presented. The purpose of the simulation is to determine the optimal design parameters. Inflamed and unaffected human joint models were constructed with a realistic geometry and tissue distributions, based on a MRI scan of a human finger with a spatial resolution of 0.2 mm. The light transport simulation is based on a weighted-photon 3D Monte Carlo method utilizing CUDA GPU acceleration. An uniform illumination of the finger within the 400-1100 nm spectral range was simulated and the photons exiting the joint were recorded using different acceptance angles. From the obtained reflectance and transmittance images the spectral and spatial features most indicative of inflammation were identified. Optimal acceptance angle and spectral bands were determined. This study demonstrates that proper selection of MSI system parameters critically affects ability of a MSI system to discriminate the unaffected and inflamed joints. The presented system design optimization approach could be applied to other pathologies.

CFD research and systems in Kawasaki Heavy Industries and its future prospects

NASA Astrophysics Data System (ADS)

Hiraoka, Koichi

1990-09-01

KHI Computational Fluid Dynamics (CFD) system is composed of VP100 computer and 2-D and 3-D Euler and/or Navier-Stokes (NS) analysis softwares. For KHI, this system has become a very powerful aerodynamic tool together with the Kawasaki 1 m Transonic Wind Tunnel. The 2-D Euler/NS software, developed in-house, is fully automated, requires no special skill, and was successfully applied to the design of YXX high lift devices and SST supersonic inlet, etc. The 3-D Euler/NS software, developed under joint research with NAL, has an interactively operated Multi-Block type grid generator and can effectively generate grids around complex airplane shapes. Due to the main memory size limitation, 3-D analysis of relatively simple shape, such as SST wing-body, was computed in-house on VP100, otherwise, such as detailed 3-D analyses of ASUKA and HOPE, were computed on NAL VP400, which is 10 times more powerful than VP100, under KHI-NAL joint research. These analysis results have very good correlation with experimental results. However, the present CFD system is less productive than wind tunnel and has applicability limitations.

Proceedings: USACERL/ASCE First Joint Conference on Expert Systems, 29-30 June 1988

DTIC Science & Technology

1989-01-01

Wong KOWLEDGE -BASED GRAPHIC DIALOGUES . o ...................... .... 80 D. L Mw 4 CONTENTS (Cont’d) ABSTRACTS ACCEPTED FOR PUBLICATION MAD, AN EXPERT...methodology of inductive shallow modeling was developed. Inductive systems may become powerful shallow modeling tools applicable to a large class of...analysis was conducted using a statistical package, Trajectories. Four different types of relationships were analyzed: linear, logarithmic, power , and

Deep Correlated Holistic Metric Learning for Sketch-Based 3D Shape Retrieval.

PubMed

Dai, Guoxian; Xie, Jin; Fang, Yi

2018-07-01

How to effectively retrieve desired 3D models with simple queries is a long-standing problem in computer vision community. The model-based approach is quite straightforward but nontrivial, since people could not always have the desired 3D query model available by side. Recently, large amounts of wide-screen electronic devices are prevail in our daily lives, which makes the sketch-based 3D shape retrieval a promising candidate due to its simpleness and efficiency. The main challenge of sketch-based approach is the huge modality gap between sketch and 3D shape. In this paper, we proposed a novel deep correlated holistic metric learning (DCHML) method to mitigate the discrepancy between sketch and 3D shape domains. The proposed DCHML trains two distinct deep neural networks (one for each domain) jointly, which learns two deep nonlinear transformations to map features from both domains into a new feature space. The proposed loss, including discriminative loss and correlation loss, aims to increase the discrimination of features within each domain as well as the correlation between different domains. In the new feature space, the discriminative loss minimizes the intra-class distance of the deep transformed features and maximizes the inter-class distance of the deep transformed features to a large margin within each domain, while the correlation loss focused on mitigating the distribution discrepancy across different domains. Different from existing deep metric learning methods only with loss at the output layer, our proposed DCHML is trained with loss at both hidden layer and output layer to further improve the performance by encouraging features in the hidden layer also with desired properties. Our proposed method is evaluated on three benchmarks, including 3D Shape Retrieval Contest 2013, 2014, and 2016 benchmarks, and the experimental results demonstrate the superiority of our proposed method over the state-of-the-art methods.

Investigation of surface wave amplitudes in 3-D velocity and 3-D Q models

NASA Astrophysics Data System (ADS)

Ruan, Y.; Zhou, Y.

2010-12-01

It has been long recognized that seismic amplitudes depend on both wave speed structures and anelasticity (Q) structures. However, the effects of lateral heterogeneities in wave speed and Q structures on seismic amplitudes has not been well understood. We investigate the effects of 3-D wave speed and 3-D anelasticity (Q) structures on surface-wave amplitudes based upon wave propagation simulations of twelve globally-distributed earthquakes and 801 stations in Earth models with and without lateral heterogeneities in wave speed and anelasticity using a Spectral Element Method (SEM). Our tomographic-like 3-D Q models are converted from a velocity model S20RTS using a set of reasonable mineralogical parameters, assuming lateral perturbations in both velocity and Q are due to temperature perturbations. Surface-wave amplitude variations of SEM seismograms are measured in the period range of 50--200 s using boxcar taper, cosine taper and Slepian multi-tapers. We calculate ray-theoretical predictions of surface-wave amplitude perturbations due to elastic focusing, attenuation, and anelastic focusing which respectively depend upon the second spatial derivative (''roughness'') of perturbations in phase velocity, 1/Q, and the roughness of perturbations in 1/Q. Both numerical experiments and theoretical calculations show that (1) for short-period (~ 50 s) surface waves, the effects of amplitude attenuation due to 3-D Q structures are comparable with elastic focusing effects due to 3-D wave speed structures; and (2) for long-period (> 100 s) surface waves, the effects of attenuation become much weaker than elastic focusing; and (3) elastic focusing effects are correlated with anelastic focusing at all periods due to the correlation between velocity and Q models; and (4) amplitude perturbations are depend on measurement techniques and therefore cannot be directly compared with ray-theoretical predictions because ray theory does not account for the effects of measurement techniques. We calculate 3-D finite-frequency sensitivity of surface-wave amplitude to perturbations in wave speed and anelasticity (Q) which fully account for the effects of elastic focusing, attenuation, anelastic focusing as well as measurement techniques. We show that amplitude perturbations calculated using wave speed and Q sensitivity kernels agree reasonably well with SEM measurements and therefore the sensitivity kernels can be used in a joint inversion of seismic phase delays and amplitudes to simultaneously image high resolution 3-D wave speed and 3-D Q structures in the upper mantle.

[The three-dimensional simulation of arytenoid cartilage movement].

PubMed

Zhang, Jun; Wang, Xuefeng

2011-08-01

Exploring the characteristics of arytenoid cartilage movement. Using Pro/ENGINEER (Pro/E) software, the cricoid cartilage, arytenoid cartilage and vocal cords were simulated to the three-dimensional reconstruction, by analyzing the trajectory of arytenoid cartilage in the joint surface from the cricoid cartilage and arytenoid cartilage composition. The 3D animation simulation showed the normal movement patterns of the vocal cords and the characteristics of vocal cords movement in occasion of arytenoid cartilage dislocation vividly. The three-dimensional model has clinical significance for arytenoid cartilage movement disorders.

Analysis and Simulation of 3D Scattering due to Heterogeneous Crustal Structure and Surface Topography on Regional Phases; Magnitude and Discrimination

DTIC Science & Technology

2009-07-07

inversion technique that is based on different weights for relatively high frequency waveform modeling of Pnl and relatively long period surface waves (Tan...et al., 2006). Pnl and surface waves are also allowed to shift in time to take into account of uncertainties in velocity structure. Joint...inversion of Pnl and surface waves provides better constraints on focal depth as well as source mechanisms. The pure strike-slip mechanism of the earthquake

HSCT noise reduction technology development at GE Aircraft Engines

NASA Technical Reports Server (NTRS)

Majjigi, Rudramuni K.

1992-01-01

The topics covered include the following: High Speed Civil Transport (HSCT) exhaust nozzle design approaches; GE aircraft engine (GEAE) HSCT acoustics research; 2DCD non-IVP suppressor ejector; key sensitivities from reference aircraft; acoustic experiments; aero-mixing experimental set-up; fluid shield nozzle; HSCT Mach 2.4 flade nozzle; noise prediction; nozzle concept for GE/Boeing joint test; scale model hot core flow path modified to prevent hub-choking CFL3-D solution; HSCT exhaust nozzle status; and key acoustic technology issues for HSCT's.

HSCT noise reduction technology development at GE Aircraft Engines

NASA Astrophysics Data System (ADS)

Majjigi, Rudramuni K.

1992-04-01

The topics covered include the following: High Speed Civil Transport (HSCT) exhaust nozzle design approaches; GE aircraft engine (GEAE) HSCT acoustics research; 2DCD non-IVP suppressor ejector; key sensitivities from reference aircraft; acoustic experiments; aero-mixing experimental set-up; fluid shield nozzle; HSCT Mach 2.4 flade nozzle; noise prediction; nozzle concept for GE/Boeing joint test; scale model hot core flow path modified to prevent hub-choking CFL3-D solution; HSCT exhaust nozzle status; and key acoustic technology issues for HSCT's.

Direct and Remote Effects of Topography and Orientation, and the Dynamics of Mesoscale Eddies

DTIC Science & Technology

2017-09-01

Diagram for Visual Reference .............36  Figure 20.  GRB with 3-D 3300-meter and Quasi -Geostrophic Comparison ..............36  THIS PAGE INTENTIONALLY...circulation model NS Navier-Stokes equations Sopt Calculated Optimal Slope Sint Interpolated Optimal Slope Qf Thermal Heat Flux QG Quasi ...surveys such as MODE1 and POLYMODE, which was the largest joint U.S.–U.S.S.R. experiment of its time (Robinson 1983). Now, with the use of

Effect of Acupotomy on FAK-PI3K Signaling Pathways in KOA Rabbit Articular Cartilages

PubMed Central

Xie, Zhan-guo; Guo, Yan; Yu, Jia-Ni; Lu, Juan; Zhang, Wei; Wang, Li-Juan; Xu, Jing; Zhao, Rui-Li; Zhou, Shuai

2017-01-01

Objective By observing the needle-knife of KOA rabbit morphology, knee joint cartilage p-FAK, p-PI3K, Aggrecan gene, and protein expression, to study the effect of needle-knife to promote cartilage cell synthesis metabolism mechanism. Method 49 male New Zealand rabbits, randomly divided into normal group (Z), model group (M), model-inhibitors (MP), needle-knife group (D), needle-knife inhibitors group (DP), electroacupuncture group (E), and electroacupuncture inhibitors (EP). RT-PCR and Western Blot were used to test each animal cartilage p-FAK, p-PI3K, and Aggrecan gene and protein expression level. Results Compared with N group, p-FAK and p-PI3K protein and mRNA expression of M group, D group, and E group increased (P < 0.05), while the protein and mRNA expression of Aggrecan reduced (P < 0.05). Compared with M group, p-FAK, p-PI3K, Aggrecan protein, and mRNA of E and D group increased (P < 0.05). Compared with E group, p-FAK, p-PI3K, Aggrecan protein, and mRNA expression of D group increased (P < 0.05); after adding inhibitors, p-FAK, p-PI3K, Aggrecan protein, and mRNA expression reduced (P < 0.05). Conclusion Needle-knife therapy can promote the repairment of cartilage cells by activating FAK-PI3K signaling pathways, promoting the synthesis of cartilage cell metabolism. PMID:29234400

Analysis of the HLA and non-HLA susceptibility loci in Japanese type 1 diabetes.

PubMed

Yamashita, Hisakuni; Awata, Takuya; Kawasaki, Eiji; Ikegami, Hiroshi; Tanaka, Shoichiro; Maruyama, Taro; Shimada, Akira; Nakanishi, Koji; Takahashi, Kazuma; Kobayashi, Tetsuro; Kawabata, Yumiko; Miyashita, Yumi; Kurihara, Susumu; Morita-Ohkubo, Tomoko; Katayama, Shigehiro

2011-11-01

We previously reported the associations of human leukocyte antigen (HLA) (DRB1 and DQB1), INS, CTLA4, IL2RA, ERBB3 and CLEC16A with Japanese type 1 diabetes (T1D). In this study, we jointly analysed these loci in addition to IFIH1 and IL7R. A maximum of 790 T1D patients and 953 control subjects were analysed. HLA was determined by sequencing-based typing. Seven non-HLA single nucleotide polymorphisms were genotyped using TaqMan assay. HLA DRB1*0405, DRB1*0901 and DRB1*0802-DQB1*0302 haplotypes were positively associated with T1D, while the DRB1*15 haplotypes were negatively associated. Non-HLA single nucleotide polymorphisms, INS, IL2RA, ERBB3, CLEC16A and IL7R were associated with T1D. By a prediction model using the HLA loci alone (HLA model) or the non-HLA loci alone (non-HLA model), it was revealed that the cumulative effect of the non-HLA model was much weaker than that of the HLA model (average increase in odds ratio: 1.17 versus 3.14). Furthermore, the area under the receiver operating characteristic curve of the non-HLA model was also much smaller than that of the HLA model (0.65 versus 0.81, p<10(-11)). Finally, a patient-only analysis revealed the susceptible HLA haplotypes and the risk allele of INS to be negatively associated with slower onset of the disease. In addition, the DRB1*0901 haplotype and the risk alleles of ERBB3, CLEC16A and CTLA4 were positively associated with the co-occurrence of thyroid autoimmunity. Although several non-HLA susceptibility genes in Japanese were confirmed trans-racially and appear to contribute to the heterogeneity of the clinical phenotypes, the cumulative effect on the ability to predict the development of T1D was weak. Copyright © 2011 John Wiley & Sons, Ltd.

Diagnostic index of 3D osteoarthritic changes in TMJ condylar morphology

NASA Astrophysics Data System (ADS)

Gomes, Liliane R.; Gomes, Marcelo; Jung, Bryan; Paniagua, Beatriz; Ruellas, Antonio C.; Gonçalves, João. Roberto; Styner, Martin A.; Wolford, Larry; Cevidanes, Lucia

2015-03-01

The aim of this study was to investigate imaging statistical approaches for classifying 3D osteoarthritic morphological variations among 169 Temporomandibular Joint (TMJ) condyles. Cone beam Computed Tomography (CBCT) scans were acquired from 69 patients with long-term TMJ Osteoarthritis (OA) (39.1 ± 15.7 years), 15 patients at initial diagnosis of OA (44.9 ± 14.8 years) and 7 healthy controls (43 ± 12.4 years). 3D surface models of the condyles were constructed and Shape Correspondence was used to establish correspondent points on each model. The statistical framework included a multivariate analysis of covariance (MANCOVA) and Direction-Projection- Permutation (DiProPerm) for testing statistical significance of the differences between healthy control and the OA group determined by clinical and radiographic diagnoses. Unsupervised classification using hierarchical agglomerative clustering (HAC) was then conducted. Condylar morphology in OA and healthy subjects varied widely. Compared with healthy controls, OA average condyle was statistically significantly smaller in all dimensions except its anterior surface. Significant flattening of the lateral pole was noticed at initial diagnosis (p < 0.05). It was observed areas of 3.88 mm bone resorption at the superior surface and 3.10 mm bone apposition at the anterior aspect of the long-term OA average model. 1000 permutation statistics of DiProPerm supported a significant difference between the healthy control group and OA group (t = 6.7, empirical p-value = 0.001). Clinically meaningful unsupervised classification of TMJ condylar morphology determined a preliminary diagnostic index of 3D osteoarthritic changes, which may be the first step towards a more targeted diagnosis of this condition.

75 FR 13046 - Airworthiness Directives; The Boeing Company Model 747-200C, -200F, -400, -400D, and -400F Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-18

.... This proposed AD results from a structural review of affected skin lap joints for widespread fatigue damage. We are proposing this AD to prevent fatigue cracking in certain lap joints, which could result in...., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. For service...

Numerical study of transient evolution of lifted jet flames: partially premixed flame propagation and influence of physical dimensions

NASA Astrophysics Data System (ADS)

Chen, Zhi; Ruan, Shaohong; Swaminathan, Nedunchezhian

2016-07-01

Three-dimensional (3D) unsteady Reynolds-averaged Navier-Stokes simulations of a spark-ignited turbulent methane/air jet flame evolving from ignition to stabilisation are conducted for different jet velocities. A partially premixed combustion model is used involving a correlated joint probability density function and both premixed and non-premixed combustion mode contributions. The 3D simulation results for the temporal evolution of the flame's leading edge are compared with previous two-dimensional (2D) results and experimental data. The comparison shows that the final stabilised flame lift-off height is well predicted by both 2D and 3D computations. However, the transient evolution of the flame's leading edge computed from 3D simulation agrees reasonably well with experiment, whereas evident discrepancies were found in the previous 2D study. This difference suggests that the third physical dimension plays an important role during the flame transient evolution process. The flame brush's leading edge displacement speed resulting from reaction, normal and tangential diffusion processes are studied at different typical stages after ignition in order to understand the effect of the third physical dimension further. Substantial differences are found for the reaction and normal diffusion components between 2D and 3D simulations especially in the initial propagation stage. The evolution of reaction progress variable scalar gradients and its interaction with the flow and mixing field in the 3D physical space have an important effect on the flame's leading edge propagation.

Direct comparison of intra-articular versus intravenous delayed gadolinium-enhanced MRI of hip joint cartilage.

PubMed

Zilkens, Christoph; Miese, Falk; Kim, Young-Jo; Jäger, Marcus; Mamisch, Tallal C; Hosalkar, Harish; Antoch, Gerald; Krauspe, Rüdiger; Bittersohl, Bernd

2014-01-01

To investigate the potential of delayed gadolinium-enhanced magnetic resonance imaging in cartilage (dGEMRIC) after intra-articular (ia) contrast agent administration at 3 Tesla (T), a paired study comparing intravenous (iv) dGEMRIC (standard) with ia-dGEMRIC was performed. Thirty-five symptomatic patients with suspected cartilage damage underwent ia- and iv-dGEMRIC. MRI was performed with a 3T system wherein the interval between both measurements was 2 weeks. For iv-dGEMRIC, FDA approved Gd-DOTA(-) was injected intravenously 45 min before the MRI scan. For ia-dGEMRIC, 10-20 mL of a 2 mM solution of Gd- DOTA(-) was injected under fluoroscopic guidance 30 min before the MRI scan. Both ia- and iv-dGEMRIC demonstrated the typical T1Gd pattern in hip joint cartilage with increasing values toward the superior regions in acetabular cartilage reflecting the higher glycosaminoglycan (GAG) content in the main weight-bearing area. Correlation analysis revealed a moderate correlation between both techniques (r = 0.439, P-value < 0.001), whereas the T1Gd values for iv-dGEMRIC were significantly higher than those for ia-dGEMRIC. This corresponds with the Bland-Altman plot analysis, which revealed a systemic bias (higher T1Gd values after iv gadolinium application) of ∼70 ms. Ia-dGEMRIC was able to reveal the characteristic T1Gd pattern in hip joint cartilage confirming the sensitivity of ia-dGEMRIC for GAG. In addition, there was a significant correlation between iv-dGEMRIC and ia-dGEMRIC. However, the T1Gd values after ia contrast media application were significantly lower than those after iv application that has to be considered for future studies. Copyright © 2013 Wiley Periodicals, Inc.

VizieR Online Data Catalog: 3D-HST+CANDELS catalog (Skelton+, 2014)

NASA Astrophysics Data System (ADS)

Skelton, R. E.; Whitaker, K. E.; Momcheva, I. G.; Brammer, G. B.; van Dokkum, P. G.; Labbe, I.; Franx, M.; van der Wel, A.; Bezanson, R.; Da Cunha, E.; Fumagalli, M.; Forster Schreiber, N.; Kriek, M.; Leja, J.; Lundgren, B. F.; Magee, D.; Marchesini, D.; Maseda, M. V.; Nelson, E. J.; Oesch, P.; Pacifici, C.; Patel, S. G.; Price, S.; Rix, H.-W.; Tal, T.; Wake, D. A.; Wuyts, S.

2015-09-01

The majority of HST/WFC3 imaging comes from the 3D-HST and CANDELS surveys which, jointly, have covered ~940arcmin2 in three infrared filters: F125W, F140W, and F160W (HST cycle 11, 17, 18 and 19). See section 2 for further explanations. (1 data file).

AESOP 3.0 Highlights: Afloat Electromagnetic Spectrum Operations Program

DTIC Science & Technology

2011-03-01

Restricted Frequency List (JRFL) MCEB Pub 8, Version 2.0.1 (1 July 2010); Tactical Information - JRFL  Enhanced Mapping Capability 2-D and 3-D maps with...includes Joint Restricted Frequency List (JRFL) frequencies UNCLASSIFIED 14 Satellite Availability & Analysis (SA2) AESOP 3.0 – SA2 v5.7.2 Software

Wavelet filtered shifted phase-encoded joint transform correlation for face recognition

NASA Astrophysics Data System (ADS)

Moniruzzaman, Md.; Alam, Mohammad S.

2017-05-01

A new wavelet-filtered-based Shifted- phase-encoded Joint Transform Correlation (WPJTC) technique has been proposed for efficient face recognition. The proposed technique uses discrete wavelet decomposition for preprocessing and can effectively accommodate various 3D facial distortions, effects of noise, and illumination variations. After analyzing different forms of wavelet basis functions, an optimal method has been proposed by considering the discrimination capability and processing speed as performance trade-offs. The proposed technique yields better correlation discrimination compared to alternate pattern recognition techniques such as phase-shifted phase-encoded fringe-adjusted joint transform correlator. The performance of the proposed WPJTC has been tested using the Yale facial database and extended Yale facial database under different environments such as illumination variation, noise, and 3D changes in facial expressions. Test results show that the proposed WPJTC yields better performance compared to alternate JTC based face recognition techniques.

Correlation-based regularization and gradient operators for (joint) inversion on unstructured meshes

NASA Astrophysics Data System (ADS)

Jordi, Claudio; Doetsch, Joseph; Günther, Thomas; Schmelzbach, Cedric; Robertsson, Johan

2017-04-01

When working with unstructured meshes for geophysical inversions, special attention should be paid to the design of the operators that are used for regularizing the inverse problem and coupling of different property models in joint inversions. Regularization constraints for inversions on unstructured meshes are often defined in a rather ad-hoc manner and usually only involve the cell to which the operator is applied and its direct neighbours. Similarly, most structural coupling operators for joint inversion, such as the popular cross-gradients operator, are only defined in the direct neighbourhood of a cell. As a result, the regularization and coupling length scales and strength of these operators depend on the discretization as well as cell sizes and shape. Especially for unstructured meshes, where the cell sizes vary throughout the model domain, the dependency of the operator on the discretization may lead to artefacts. Designing operators that are based on a spatial correlation model allows to define correlation length scales over which an operator acts (called footprint), reducing the dependency on the discretization and the effects of variable cell sizes. Moreover, correlation-based operators can accommodate for expected anisotropy by using different length scales in horizontal and vertical directions. Correlation-based regularization operators also known as stochastic regularization operators have already been successfully applied to inversions on regular grids. Here, we formulate stochastic operators for unstructured meshes and apply them in 2D surface and 3D cross-well electrical resistivity tomography data inversion examples of layered media. Especially for the synthetic cross-well example, improved inversion results are achieved when stochastic regularization is used instead of a classical smoothness constraint. For the case of cross-gradients operators for joint inversion, the correlation model is used to define the footprint of the operator and weigh the contributions of the property values that are used to calculate the cross-gradients. In a first series of synthetic-data tests, we examined the mesh dependency of the cross-gradients operators. Compared to operators that are only defined in the direct neighbourhood of a cell, the dependency on the cell size of the cross-gradients calculation is markedly reduced when using operators with larger footprints. A second test with synthetic models focussed on the effect of small-scale variabilities of the parameter value on the cross-gradients calculation. Small-scale variabilities that are superimposed on a global trend of the property value can potentially degrade the cross-gradients calculation and destabilize joint inversion. We observe that the cross-gradients from operators with footprints larger than the length scale of the variabilities are less affected compared to operators with a small footprint. In joint inversions on unstructured meshes, we thus expect the correlation-based coupling operators to ensure robust coupling on a physically meaningful scale.

Rigorous Approach in Investigation of Seismic Structure and Source Characteristicsin Northeast Asia: Hierarchical and Trans-dimensional Bayesian Inversion

NASA Astrophysics Data System (ADS)

Mustac, M.; Kim, S.; Tkalcic, H.; Rhie, J.; Chen, Y.; Ford, S. R.; Sebastian, N.

2015-12-01

Conventional approaches to inverse problems suffer from non-linearity and non-uniqueness in estimations of seismic structures and source properties. Estimated results and associated uncertainties are often biased by applied regularizations and additional constraints, which are commonly introduced to solve such problems. Bayesian methods, however, provide statistically meaningful estimations of models and their uncertainties constrained by data information. In addition, hierarchical and trans-dimensional (trans-D) techniques are inherently implemented in the Bayesian framework to account for involved error statistics and model parameterizations, and, in turn, allow more rigorous estimations of the same. Here, we apply Bayesian methods throughout the entire inference process to estimate seismic structures and source properties in Northeast Asia including east China, the Korean peninsula, and the Japanese islands. Ambient noise analysis is first performed to obtain a base three-dimensional (3-D) heterogeneity model using continuous broadband waveforms from more than 300 stations. As for the tomography of surface wave group and phase velocities in the 5-70 s band, we adopt a hierarchical and trans-D Bayesian inversion method using Voronoi partition. The 3-D heterogeneity model is further improved by joint inversions of teleseismic receiver functions and dispersion data using a newly developed high-efficiency Bayesian technique. The obtained model is subsequently used to prepare 3-D structural Green's functions for the source characterization. A hierarchical Bayesian method for point source inversion using regional complete waveform data is applied to selected events from the region. The seismic structure and source characteristics with rigorously estimated uncertainties from the novel Bayesian methods provide enhanced monitoring and discrimination of seismic events in northeast Asia.