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1

Nonlinear Analysis of Bonded Composite Single-LAP Joints  

NASA Technical Reports Server (NTRS)

This study presents a semi-analytical solution method to analyze the geometrically nonlinear response of bonded composite single-lap joints with tapered adherend edges under uniaxial tension. The solution method provides the transverse shear and normal stresses in the adhesive and in-plane stress resultants and bending moments in the adherends. The method utilizes the principle of virtual work in conjunction with von Karman s nonlinear plate theory to model the adherends and the shear lag model to represent the kinematics of the thin adhesive layer between the adherends. Furthermore, the method accounts for the bilinear elastic material behavior of the adhesive while maintaining a linear stress-strain relationship in the adherends. In order to account for the stiffness changes due to thickness variation of the adherends along the tapered edges, their in-plane and bending stiffness matrices are varied as a function of thickness along the tapered region. The combination of these complexities results in a system of nonlinear governing equilibrium equations. This approach represents a computationally efficient alternative to finite element method. Comparisons are made with corresponding results obtained from finite-element analysis. The results confirm the validity of the solution method. The numerical results present the effects of taper angle, adherend overlap length, and the bilinear adhesive material on the stress fields in the adherends, as well as the adhesive, of a single-lap joint

Oterkus, E.; Barut, A.; Madenci, E.; Smeltzer, S. S.; Ambur, D. R.

2004-01-01

2

Shear Strength of Single Lap Joint Aluminium-Thermoplastic Natural Rubber (Al-TPNR) Laminated Composite  

NASA Astrophysics Data System (ADS)

In this work, we studied the effect of surface treatment on the aluminium surface and a coupling agent to improve adhesion between aluminium with organic polymer. Thermoplastic natural rubber (TPNR) matrix was prepared by melt blending of natural rubber (NR), liquid natural rubber (LNR) compatibilizer, linear low density polyethylene (LLDPE) and polyethylene grafted maleic anhydride (PE-g-MAH). The PEgMAH concentration used was varied from 0% - 25%. In addition, the aluminium surface was pre-treated with 3-glycidoxy propyl trimethoxy silane (3-GPS) to enhance the mechanical properties of laminated composite. It was found that the shear strength of single lap joint Al-TPNR laminated composite showing an increasing trend as a function of PE-g-MAH contents for the 3-GPS surface treated aluminium. Moreover, the scanning electron microscope (SEM) revealed that the strength improvement was associated with the chemical state of the compound involved.

Muzakkar, M. Z.; Ahmad, S.; Yarmo, M. A.; Jalar, A.; Bijarimi, M.

2013-04-01

3

A Semi-Analytical Method for Determining the Energy Release Rate of Cracks in Adhesively-Bonded Single-Lap Composite Joints  

NASA Technical Reports Server (NTRS)

A semi-analytical method for determining the strain energy release rate due to a prescribed interface crack in an adhesively-bonded, single-lap composite joint subjected to axial tension is presented. The field equations in terms of displacements within the joint are formulated by using first-order shear deformable, laminated plate theory together with kinematic relations and force equilibrium conditions. The stress distributions for the adherends and adhesive are determined after the appropriate boundary and loading conditions are applied and the equations for the field displacements are solved. Based on the adhesive stress distributions, the forces at the crack tip are obtained and the strain energy release rate of the crack is determined by using the virtual crack closure technique (VCCT). Additionally, the test specimen geometry from both the ASTM D3165 and D1002 test standards are utilized during the derivation of the field equations in order to correlate analytical models with future test results. The system of second-order differential field equations is solved to provide the adherend and adhesive stress response using the symbolic computation tool, Maple 9. Finite element analyses using J-integral as well as VCCT were performed to verify the developed analytical model. The finite element analyses were conducted using the commercial finite element analysis software ABAQUS. The results determined using the analytical method correlated well with the results from the finite element analyses.

Yang, Charles; Sun, Wenjun; Tomblin, John S.; Smeltzer, Stanley S., III

2007-01-01

4

Fatigue strength of a single lap joint SPR-bonded  

SciTech Connect

In the last years, hybrid joints, meaning with this the joints which consist in combining a traditional mechanical joint to a layer of adhesive, are gradually attracting the attention of various sectors of the construction of vehicles and transportation industries, for their better performance compared to just mechanical joints (self-piercing riveting SPR, riveting, and so on) or just to bonded joints.The paper investigates the fatigue behavior of a single lap joint self-piercing riveted (SPR) and bonded throughout fatigue tests. The considered geometric configuration allowed the use of two rivets placed longitudinally; an epoxy resin was used as adhesive. In the first part of the work static characterization of the joints was carried out through tensile tests. Then fatigue tests were made with the application of different levels of load. The fatigue curves were also obtained at the varying the distance between the two rivets in order to better assess the joint strength for a given length of overlap.

Di Franco, G.; Fratini, L.; Pasta, A. [University of Palermo-Dept. of Industrial Engineering (Italy)

2011-05-04

5

Modified single lap joint (MSLJ) test configuration for the determination of adhesive fracture energy  

NASA Astrophysics Data System (ADS)

In this work, a modification has been proposed to the traditional single lap joint (SLJ) configuration, to overcome the wide scatter in the fracture toughness measurement due to adhesive fillets. This modification, referred to as the Modified Single Lap Joint (MSLJ), is made by implanting end pre-cracks in the adhesive layer at the center of the bond line in a conventional SLJ. This ensured that during testing, the crack propagated from both ends of the overlap and reduced the effect of spew fillets. MSLJ joints made from unidirectional fibre composite substrates (913C - HTA 12K 5-34%) and either of two types of (Redux 322 and Redux 335K) film adhesive were tested to measure the adhesive fracture energy, Gac. The values of Gac measured were compared with those from similar tests conducted on SLJ and double cantilever beam (DCB) configurations. It was observed that the scatter in the fracture energy measurements obtained from the MSLJ specimens were reduced by more than 30% in comparison with those from the SLJ specimens. The values of adhesive fracture energy from the MSLJ and DCB test geometries were in good agreement. These results are especially useful in the critical design of structural components for aerospace and defense applications as a typical design engineer can use the value of Gac to design for how long an adhesively bonded joint will last when subjected to stresses in friendly or hostile environments.

Kumar, S. B.; Sridhar, I.; Sivashanker, S.; Bag, Asim; Osiyemi, S. O.

2005-04-01

6

Dynamic response of adhesively bonded single-lap joints with a void subjected to harmonic peeling  

E-print Network

Dynamic response of adhesively bonded single-lap joints with a void subjected to harmonic peeling is evaluated. The bonded joint is modelled as a Euler­Bernoulli beam joined with an adhesive and constrained overall length of the bonded joint t adhesive thickness w width of the beams yi transverse displacement

Vaziri, Ashkan

7

A critical examination of stresses in an elastic single lap joint  

NASA Technical Reports Server (NTRS)

The results of an approximate nonlinear finite-element analysis of a single lap joint are presented and compared with the results of a linear finite-element analysis, and the geometric nonlinear effects caused by the load-path eccentricity on the adhesive stress distributions are determined. The results from finite-element, Goland-Reissner, and photoelastic analyses show that for a single lap joint the effect of the geometric nonlinear behavior of the joint has a sizable effect on the stresses in the adhesive. The Goland-Reissner analysis is sufficiently accurate in the prediction of stresses along the midsurface of the adhesive bond to be used for qualitative evaluation of the influence of geometric or material parametric variations. Detailed stress distributions in both the adherend and adhesive obtained from the finite-element analysis are presented to provide a basis for comparison with other solution techniques.

Cooper, P. A.; Sawyer, J. W.

1979-01-01

8

A Single-Lap Joint Adhesive Bonding Optimization Method Using Gradient and Genetic Algorithms  

NASA Technical Reports Server (NTRS)

A natural process for any engineer, scientist, educator, etc. is to seek the most efficient method for accomplishing a given task. In the case of structural design, an area that has a significant impact on the structural efficiency is joint design. Unless the structure is machined from a solid block of material, the individual components which compose the overall structure must be joined together. The method for joining a structure varies depending on the applied loads, material, assembly and disassembly requirements, service life, environment, etc. Using both metallic and fiber reinforced plastic materials limits the user to two methods or a combination of these methods for joining the components into one structure. The first is mechanical fastening and the second is adhesive bonding. Mechanical fastening is by far the most popular joining technique; however, in terms of structural efficiency, adhesive bonding provides a superior joint since the load is distributed uniformly across the joint. The purpose of this paper is to develop a method for optimizing single-lap joint adhesive bonded structures using both gradient and genetic algorithms and comparing the solution process for each method. The goal of the single-lap joint optimization is to find the most efficient structure that meets the imposed requirements while still remaining as lightweight, economical, and reliable as possible. For the single-lap joint, an optimum joint is determined by minimizing the weight of the overall joint based on constraints from adhesive strengths as well as empirically derived rules. The analytical solution of the sin-le-lap joint is determined using the classical Goland-Reissner technique for case 2 type adhesive joints. Joint weight minimization is achieved using a commercially available routine, Design Optimization Tool (DOT), for the gradient solution while an author developed method is used for the genetic algorithm solution. Results illustrate the critical design variables as a function of adhesive properties and convergences of different joints based on the two optimization methods.

Smeltzer, Stanley S., III; Finckenor, Jeffrey L.

1999-01-01

9

Strain measurement within a single-lap joint using embedded strain gages  

NASA Technical Reports Server (NTRS)

An experimental method used to measure the in-plane normal-axial strains produced within a single-lap joint is described in which a resistance-foil strain gage is embedded within the joint prior to curing of the adhesive. Nominal dimensions of the titanium Ti-6-4 adherends were 0.13 x 2.5 x 12.7 cm and an overlap of 2.5 cm was used. The joint was bonded with FM-300 structural adhesive. The average ultimate shear strength of the gaged specimens and control specimens was 16.1 MPa and 14.1 MPa. A significant advantage of the proposed method is that strains internal to the joint are measured, rather than strains at an external edge. The presence of the gage was found to be not detrimental to bond performance.

Tuttle, M. E.; Barthelemy, B. M.; Brinson, H. F.

1984-01-01

10

A two-dimensional stress analysis of single lap joints subjected to external bending moments  

SciTech Connect

The stress distribution of single lap adhesive joints subjected to external bending moments are analyzed as a three-body contact problem by using a two-dimensional theory of elasticity. In the analysis, two similar adherends and an adhesive are replaced by finite strips, respectively. In the numerical calculations, the effects of the ratio of Young;s modulus of adherends to that of adhesive and the adhesive thickness on the stress distribution at the interface are examined. As the results, it is seen that the stress singularity causes at the edges of the interfaces and the peel stress at the edges of the interface increases with a decrease of Young`s modulus of the adherends. In addition, photoelastic experiments are carried out. A fairly good agreement is seen between the analytical and the experimental results.

Sawa, Toshiyuki; Nakano, Katsuyuki; Toratani, Hiroshi [Yamanashi Univ., Kofu (Japan). Dept. of Mechanical Engineering

1995-11-01

11

Stress-Strain Analysis of Single-Lap Tensile Loaded Adhesive Joints  

SciTech Connect

Both, experimental investigation and finite element analysis of single-lap adhesive joints subjected to tension have been done to find out an optimal overlap length. As the adherend material aluminum was considered with the two component high-strength engineering adhesive for the bonding of the layers. The thickness of the sheet metal layer was 1,95 mm, while adhesive was 0,15 mm thick. The width of all thin plates was 30 mm, but the overlap length varied as 15, 20, 30, 40 and 60 mm. Real mechanical properties of all materials in the joint have been determined experimentally. Obtained results proved that the overlap length affects directly the joint tensile strength, where an optimum value of overlap length can be defined. Finite element analysis of stress and strain fields could help to determine the moment when the crack initiates at the joint overlap end. In such a manner, complex mechanisms of failure of adhesive joints could be better understood.

Raos, Pero; Kozak, Drazan; Lucic, Mirjana [University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Trg Ivane Brlic-Mazuranic 2, HR-35000 Slavonski Brod (Croatia)

2007-05-17

12

Global-Local Finite Element Analysis of Bonded Single-Lap Joints  

NASA Technical Reports Server (NTRS)

Adhesively bonded lap joints involve dissimilar material junctions and sharp changes in geometry, possibly leading to premature failure. Although the finite element method is well suited to model the bonded lap joints, traditional finite elements are incapable of correctly resolving the stress state at junctions of dissimilar materials because of the unbounded nature of the stresses. In order to facilitate the use of bonded lap joints in future structures, this study presents a finite element technique utilizing a global (special) element coupled with traditional elements. The global element includes the singular behavior at the junction of dissimilar materials with or without traction-free surfaces.

Kilic, Bahattin; Madenci, Erdogan; Ambur, Damodar R.

2004-01-01

13

Dynamic strain distribution measurement and crack detection of an adhesive-bonded single-lap joint under cyclic loading using embedded FBG  

NASA Astrophysics Data System (ADS)

In this study, the dynamic strain distribution measurement of an adhesive-bonded single-lap joint was carried out in a cyclic load test using a fiber Bragg grating (FBG) sensor embedded into the adhesive/adherend interface along the overlap length direction. Unidirectional carbon fiber reinforced plastic (CFRP) substrates were bonded by epoxy resin to form the joint, and the FBG sensor was embedded into the surface of one substrate during its curing. The measurement was carried out with a sampling rate of 5 Hz by the sensing system, based on the optical frequency domain reflectometry (OFDR) throughout the test. A finite element analysis (FEA) was performed for the measurement evaluation using a three-dimensional model, which included the embedded FBG sensor. The crack detection method, based on the longitudinal strain distribution measurement, was introduced and performed to estimate the cracks that occurred at the adhesive/adherend interface in the test.

Ning, Xiaoguang; Murayama, Hideaki; Kageyama, Kazuro; Wada, Daichi; Kanai, Makoto; Ohsawa, Isamu; Igawa, Hirotaka

2014-10-01

14

Nonlinear Analysis of Bonded Composite Tubular Lap Joints  

NASA Technical Reports Server (NTRS)

The present study describes a semi-analytical solution method for predicting the geometrically nonlinear response of a bonded composite tubular single-lap joint subjected to general loading conditions. The transverse shear and normal stresses in the adhesive as well as membrane stress resultants and bending moments in the adherends are determined using this method. The method utilizes the principle of virtual work in conjunction with nonlinear thin-shell theory to model the adherends and a cylindrical shear lag model to represent the kinematics of the thin adhesive layer between the adherends. The kinematic boundary conditions are imposed by employing the Lagrange multiplier method. In the solution procedure, the displacement components for the tubular joint are approximated in terms of non-periodic and periodic B-Spline functions in the longitudinal and circumferential directions, respectively. The approach presented herein represents a rapid-solution alternative to the finite element method. The solution method was validated by comparison against a previously considered tubular single-lap joint. The steep variation of both peeling and shearing stresses near the adhesive edges was successfully captured. The applicability of the present method was also demonstrated by considering tubular bonded lap-joints subjected to pure bending and torsion.

Oterkus, E.; Madenci, E.; Smeltzer, S. S., III; Ambur, D. R.

2005-01-01

15

Design, fabrication and test of graphite/polyimide composite joints and attachments for advanced aerospace vehicles  

NASA Technical Reports Server (NTRS)

Results of an experimental program to develop several types of graphite/polyimide (GR/PI) bonded and bolted joints for lightly loaded flight components for advanced space transportation systems and high speed aircraft are presented. Tasks accomplished include: a literature survey; design of static discriminator specimens; design allowables testing; fabrication of test panels and specimens; small specimen testing; and standard joint testing. Detail designs of static discriminator specimens for each of the four major attachment types are presented. Test results are given for the following: (1) transverse tension of Celion 3000/PMR-15 laminate; (2) net tension of a laminate for both a loaded and unloaded bolt hole; (3) comparative testing of bonded and co-cured doublers along with pull-off tests of single and double bonded angles; (4) single lap shear tests, transverse tension and coefficient of thermal expansion tests of A7F (LARC-13 amide-imide modified) adhesive; and (5) tension tests of standard single lap, double lap, and symmetric step lap bonded joints. Also, included are results of a finite element analysis of a single lap bonded composite joint.

Barclay, D. L.

1980-01-01

16

Co-cured composite joint strength investigation based on behavior characterization of the [0/ (+/-)theta/90]s family  

NASA Astrophysics Data System (ADS)

Joints provide a path for transfer of load and are important components in an assembly of structures, particularly in translating joint strength improvements directly to significant cost savings. These cost savings are more evident in composite joints since manufacturing of more complex single piece components results in a reduction of both part count and labor. An improvement in joint strength for co-cured composite joints through minimized free-edge delamination was investigated for a quasi-isotropic [0/ +/- 45/90]s lay-up based on the quantitative assessments of the quasi-static and fatigue strength and qualitative understanding of the fatigue damage initiation and propagation for the [0/ +/- theta/90]s family of co-cured composite joints. A previously proposed co-cured joint concept, the Single Nested Overlap (SNO) joint, was compared against a Straight Laminate (SL) and a single lap joint. The SL represents a "perfect" joint and serves as an upper bound whereas the single lap joint represents the simplest generic joint and is the base design for the SNO joint concept. Three categorized failure types, which represent the predominant failure modes in the SL, single lap, and SNO joints, along with two different fatigue strength indicators were used for quasi-static and fatigue strength comparison. With fatigue run-out defined at 1x106 cycles, the fatigue damage initiation and propagation at high loadings was monitored with an Infrared Thermoelastic Stress Analysis (IR-TSA) technique, while a damage type comparison was used at low loadings. Quasi-static Acoustic Emission (AE) counts were observed to be Fatigue Limit (FL) indicators for [0/ +/- theta/90] s SL and SNO joints. The validity of these FL indicators was also assessed in the comparison of damage types.

Tan, Xinyuan

17

Test and analysis of Celion 3000/PMR-15, graphite/polyimide bonded composite joints: Data report  

NASA Technical Reports Server (NTRS)

Standard single lap, double lap and symmetric step lap bonded joints of Celion 3000/PMR-15 graphite/polyimide composite were evaluated. Composite to composite and composite to titanium joints were tested at 116 K (-250 F), 294 K (70 F) and 561 K (550 F). Joint parameters evaluated are lap length, adherend thickness, adherend axial stiffness, lamina stacking sequence and adherend tapering. Advanced joint concepts were examined to establish the change in performance of preformed adherends, scalloped adherends and hybrid systems. The material properties of the high temperature adhesive, designated A7F, used for bonding were established. The bonded joint tests resulted in interlaminar shear or peel failures of the composite and there were very few adhesive failures. Average test results agree with expected performance trends for the various test parameters. Results of finite element analyses and of test/analysis correlations are also presented.

Cushman, J. B.; Mccleskey, S. F.; Ward, S. H.

1982-01-01

18

Formation of tough composite joints  

SciTech Connect

Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si{sub 3}N{sub 4}-coated fibers had a 0/90{degree} architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses.

Brun, M.K. [GE Corporate Research and Development, Schenectady, NY (United States)

1997-05-01

19

Computational modelling of thermal impact welded PEEK\\/steel single lap tensile specimens  

Microsoft Academic Search

In this contribution, an interfacial traction-separation-law based on elastoplasticity with Lemaitre-type-damage is applied. Related constitutive equations are decoupled with respect to a local orthonormal frame such that the stress–strain response is controlled independently in these directions. The constitutive traction-separation-law is applied to the simulation of thermal impact welded (TIW) single lap tensile specimens. The specimens consist of two steel substrates

Johannes Utzinger; Martin Bos; Martin Floeck; Andreas Menzel; Ellen Kuhl; Rainer Renz; Klaus Friedrich; Alois K. Schlarb; Paul Steinmann

2008-01-01

20

Debonding of Stitched Composite Joints: Testing and Analysis  

NASA Technical Reports Server (NTRS)

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and analytical study. The experimental study was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation ofthe debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The strain energy release rates at the debond front were calculated using a finite element-based technique. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches effectively reduced mode I to zero, but had less of an effect on modes II and III.

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

21

Simplified procedures for designing composite bolted joints  

NASA Technical Reports Server (NTRS)

Simplified procedures are described to design and analyze single and multi-bolt composite joints. Numerical examples illustrate the use of these methods. Factors affecting composite bolted joints are summarized. References are cited where more detailed discussion is presented on specific aspects of composite bolted joints. Design variables associated with these joints are summarized in the appendix.

Chamis, Christos C.

1988-01-01

22

THERMAL BEHAVIOR DURING THERMOPLASTIC COMPOSITES RESISTANCE WELDING  

Microsoft Academic Search

Two- and three- dimensional heat transfer finite element models of the resistance-welding process for joining thermoplastic composite laminates were developed. The models simulated a resistance welded single lap-shear joint using 16-layer unidirectional APC- 2\\/AS4 laminates. The heating element consisted of a stainless steel metal mesh sandwiched between neat PEEK films. The heat was generated at the bond surface by applying

Edith Talbot; Ali Yousefpour; Pascal Hubert; Mehdi Hojjati

23

Adhesive-Bonded Composite Joint Analysis with Delaminated Surface Ply Using Strain-Energy Release Rate  

NASA Technical Reports Server (NTRS)

This paper presents an analytical model to determine the strain energy release rate due to an interlaminar crack of the surface ply in adhesively bonded composite joints subjected to axial tension. Single-lap shear-joint standard test specimen geometry with thick bondline is followed for model development. The field equations are formulated by using the first-order shear-deformation theory in laminated plates together with kinematics relations and force equilibrium conditions. The stress distributions for the adherends and adhesive are determined after the appropriate boundary and loading conditions are applied and the equations for the field displacements are solved. The system of second-order differential equations is solved to using the symbolic computation tool Maple 9.52 to provide displacements fields. The equivalent forces at the tip of the prescribed interlaminar crack are obtained based on interlaminar stress distributions. The strain energy release rate of the crack is then determined by using the crack closure method. Finite element analyses using the J integral as well as the crack closure method are performed to verify the developed analytical model. It has been shown that the results using the analytical method correlate well with the results from the finite element analyses. An attempt is made to predict the failure loads of the joints based on limited test data from the literature. The effectiveness of the inclusion of bondline thickness is justified when compared with the results obtained from the previous model in which a thin bondline and uniform adhesive stresses through the bondline thickness are assumed.

Chadegani, Alireza; Yang, Chihdar; Smeltzer, Stanley S. III

2012-01-01

24

Delamination and Stitched Failure in Stitched Composite Joints  

NASA Technical Reports Server (NTRS)

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and finite element study. The experimental program was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The experimentally determined debond length vs. applied load was used as an input parameter in the finite element analysis of both configurations. The strain energy release rates at the debond from were calculated using plate finite elements. Nonlinear fastener elements were used to model the stitches and multipoint constraints were used to model the contact problem. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches were effective in reducing mode I to zero, but had less of an effect on modes II and III.

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

25

Surface preparation of adhesively bonded joints  

SciTech Connect

For the bonding of structures, it is essential that correct surface preparation is completed to ensure both a reliable and a durable bond. In a controlled environment this can be achieved easily, but difficulties can occur in the field. This paper is a compilation of research completed in the area of surface preparation for the bonding of aluminum and graphite epoxy composites. Finite element analysis software MSC/NASTRAN has been used to investigate the effect of adhesion on the strength and failure characteristics of a single lap joint.

Hogg, I.C.; Janardhana, M.N. [Royal Melbourne Institute of Technology, Victoria (Australia). Dept. of Aerospace Engineering

1993-12-31

26

Adhesive joint and composites modeling in SIERRA.  

SciTech Connect

Polymers and fiber-reinforced polymer matrix composites play an important role in many Defense Program applications. Recently an advanced nonlinear viscoelastic model for polymers has been developed and incorporated into ADAGIO, Sandia's SIERRA-based quasi-static analysis code. Standard linear elastic shell and continuum models for fiber-reinforced polymer-matrix composites have also been added to ADAGIO. This report details the use of these models for advanced adhesive joint and composites simulations carried out as part of an Advanced Simulation and Computing Advanced Deployment (ASC AD) project. More specifically, the thermo-mechanical response of an adhesive joint when loaded during repeated thermal cycling is simulated, the response of some composite rings under internal pressurization is calculated, and the performance of a composite container subjected to internal pressurization, thermal loading, and distributed mechanical loading is determined. Finally, general comparisons between the continuum and shell element approaches for modeling composites using ADAGIO are given.

Ohashi, Yuki; Brown, Arthur A.; Hammerand, Daniel Carl; Adolf, Douglas Brian; Chambers, Robert S.; Foulk, James W., III (.,; )

2005-11-01

27

Modeling the Influence of Stitching on Delamination Growth in Stitched Warp-Knit Composite Lap Joints  

NASA Technical Reports Server (NTRS)

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and analytical study. The experimental study was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The strain energy release rates at the debond front were calculated using a finite element-based technique. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches effectively reduced mode I to zero, but had less of an effect on modes II and III.

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

28

Analysis of mechanical joint in composite cylinder  

NASA Astrophysics Data System (ADS)

Joining techniques of composite materials are of great interest in cylindrical structures as the application of composites is widely used for weight-sensitive structures. Little information for the mechanical fastening joint of the laminated shell structure is available in the literature. In this study, a finite element program, which was based on the first order shear deformation theory, was developed for the analysis of the mechanical joint in the laminated composite structure. The failure of the mechanical fastening joint for the laminated graphite/epoxy cylinder subject to internal pressure was analyzed by using the developed program. Modeling of the bolt head in the composite cylinder was studied, and the effect of steel reinforcement outside the composite cylinder on the failure was investigated. The stress component near the bolt head was influenced by the size of the bolt head. The failure load and the failure mode were dependent on the bolt diameter, the number of bolts, and fiber orientation. The failure load was constant when the edge distance exceeds three times the bolt diameter.

Hong, C. S.; Kim, Y. W.; Park, J. S.

29

Analysis of adhesively bonded composite lap joints  

SciTech Connect

A new nonlinear formulation is developed for the governing equations for the shear and peel stresses in adhesively bonded composite double lap joints. The new formulation allows arbitrary nonlinear stress-strain characteristics in both shear and peel behavior. The equations are numerically integrated using a shooting technique and Newton-Raphson method behind a user friendly interface. The failure loads are predicted by utilizing the maximum stress criterion, interlaminar delamination and the energy density failure criteria. Numerical examples are presented to demonstrate the effect of the nonlinear adhesive behavior on the stress distribution and predict the failure load and the associated mode.

Tong, L. [Cooperative Research Centre for Aerospace Structures, Bankstown (Australia); Kuruppu, M.; Kelly, D. [Univ. of New South Wales, Sydney (Australia). School of Mechanical and Manufacturing Engineering

1994-12-31

30

Cyclic Fatigue Behaviour of Adhesive Joints.  

National Technical Information Service (NTIS)

In the last six months we have: (a) Concentrated our efforts on the fatigue failure of carbon-fibre PEEK/AFl63 lap joints, and in particular we have started to predict the life time of single-lap joints under cyclic fatigue loading. The analysis is based ...

A. J. Kinloch, T. Toh

1995-01-01

31

Criterion for mixed mode fracture in composite bonded joints  

NASA Technical Reports Server (NTRS)

A study was undertaken to characterize the debond growth mechanism of adhesively bonded composite joints under mode I, mixed mode I-II, and mode II static loadings. The bonded system consisted of graphite-epoxy composite adherends bonded with a toughened epoxy adhesive. The mode I, mode II and mixed mode I-II fracture energies of the tested adhesives were found to be equal to each other. The criterion for mixed mode fracture in composite bonded joints was found.

Mall, S.; Kochhar, N. K.

1986-01-01

32

Adhesive Bonding Characterization of Composite Joints for Cryogenic Usage  

NASA Technical Reports Server (NTRS)

The development of polymer composite cryogenic tanks is a critical step in creating the next generation of launch vehicles. Future reusable launch vehicles need to minimize the gross liftoff weight (GLOW). This weight reduction is possible due to the large reduction in weight that composite materials can provide over current aluminum technology. In addition to composite technology, adhesively bonded joints potentially have several benefits over mechanically fastened joints, such as weight savings and cryogenic fluid containment. Adhesively bonded joints may be used in several areas of these cryogenic tanks, such as in lobe-to-lobe joints (in a multi-lobe concept), skirt-to-tank joint, strut-to-tank joint, and for attaching stringers and ring frames. The bonds, and the tanks themselves, must be able to withstand liquid cryogenic fuel temperatures that they contain. However, the use of adhesively bonded composite joints at liquid oxygen and hydrogen temperatures is largely unknown and must be characterized. Lockheed Martin Space Systems Company, Michoud Operations performed coupon-level tests to determine effects of material selection, cure process parameters, substrate surface preparation, and other factors on the strength of these composite joints at cryogenic temperatures. This led to the selection of a material and process that would be suitable for a cryogenic tank. KEY WORDS: Composites, Adhesive Bonding, Cryogenics

Graf, Neil A.; Schieleit, Gregory F.; Biggs, Robert

2000-01-01

33

Dual resin bonded joints in polyetheretherketone (PEEK) matrix composites  

Microsoft Academic Search

The paper describes applications of the dual resin (miscible polymer) bonding technique (Smiley, 1989) developed as an alternative to traditional bonding approaches to joining thermoplastic matrix composite subassemblies into structures. In the experiments, the performance of joint geometries, such as those that could be used to assemble large truss structures in space, are investigated using truss joint models consisting of

Steve Zelenak; Donald W. Radford; Michael W. Dean

1993-01-01

34

Failure analyses of composite bolted joints  

NASA Technical Reports Server (NTRS)

The complex failure behavior exhibited by bolted joints of graphite epoxy (Hercules AS/3501) was investigated for the net tension, bearing and shearout failure modes using combined analytical and experimental techniques. Plane stress, linear elastic, finite element methods were employed to determine the two dimensional state of stress resulting from a loaded hole in a finite width, semiinfinite strip. The stresses predicted by the finite element method were verified by experiment to lend credence to the analysis. The influence of joint geometric parameters on the state of stress and resultant strength of the joint was also studied. The resulting functional relationships found to exist between bolted joint strength and the geometric parameters, were applied in the formulation of semiempirical strength models for the basic failure modes. A point stress failure criterion was successfully applied as the failure criterion for the net tension and shearout failure modes.

Wilson, D. W.; Gillespie, J. W.; York, J. L.; Pipes, R. B.

1980-01-01

35

The effects of inherent flaws on the time and rate dependent failure of adhesively bonded joints  

NASA Technical Reports Server (NTRS)

Inherent flaws, as well as the effects of rate and time, are shown by tests on viscoelastic adhesive-bonded single lap joints to be as critical in joint failure as environmental and stress concentration effects, with random inherent flaws and loading rate changes resulting in an up to 40% reduction in joint strength. It is also found that the asymptotic creep stress, below which no delayed failure may occur, may under creep loading be as much as 45% less than maximum adhesive strength. Attention is given to test results for the case of titanium-LARC-3 adhesive single-lap specimens.

Sancaktar, E.; Padgilwar, S.

1982-01-01

36

Criterion for mixed mode fracture in composite bonded joints  

NASA Technical Reports Server (NTRS)

A study was undertaken to characterize the debond growth mechanism of adhesively bonded composite joints under mode I, mixed mode I-II, and mode II static loadings. The bonded system consisted of graphite/epoxy (T300/5208) composite adherends bonded with a toughened epoxy (EC 3445) adhesive. The mode I, mode II and mixed-mode I-II fracture energies of the tested adhesive were found to be equal to each other. Furthermore, the criterion for mixed mode fracture in composite bonded joints was determined.

Mall, S.; Kochhar, N. K.

1986-01-01

37

Critical composite joint subcomponents: Analysis and test results  

NASA Technical Reports Server (NTRS)

This program has been conducted to develop the technology for critical structural joints of a composite wing structure meeting design requirements for a 1990 commercial transport aircraft. A prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Load sharing between bolts in multirow joints was computed by a nonlinear analysis program (A4FJ) which was used both to assess the efficiency of different joint design concepts and to predict the strengths of large test articles representing a section from a wing root chord-wise splice. In most cases, the predictions were accurate to within a few percent of the test results. A highlight of these tests was the consistent ability to achieve gross-section failure strains on the order of 0.005 which represents a considerable improvement over the state of the art. The improvement was attained largely as the result of the better understanding of the load sharing in multirow joints provided by the analysis. The typical load intensity on the structural joints was about 40 to 45 thousand pound per inch in laminates having interspersed 37 1/2-percent 0-degree plies, 50-percent + or - 45-degrees plies and 12 1/2-percent 90-degrees plies. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.010-inch thick unidirectional tape.

Bunin, B. L.

1983-01-01

38

Predicting the service-life of adhesively-bonded joints  

Microsoft Academic Search

A fracture-mechanics approach has been used to predict the cyclic-fatigue performance of the adhesively-bonded single-lap joint and a typical bonded component, represented by an adhesively-bonded `top-hat' box-beam joint. The joints were tested under cyclic-fatigue loading in either a `wet' or `dry' environment, respectively. Several steps were needed to predict the cyclic-fatigue lifetime of these joints. Firstly, fracture-mechanics tests were used

A. J. Curley; H. Hadavinia; A. J. Kinloch; A. C. Taylor

2000-01-01

39

Preliminary design of composite riser stress joints  

Microsoft Academic Search

The objective of this paper is to investigate the technical feasibility of using hybrid carbon and glass-fibre reinforced epoxy composite tubes as production risers for a tension leg oil platform tethered in 1000m of water. The axial forces and bending moment distributions applied to the riser were calculated by hydrodynamic finite element analysis, taking into consideration the extreme environmental conditions,

L. C. M. Meniconi; S. R. Reid; P. D. Soden

2001-01-01

40

Room Temperature and Elevated Temperature Composite Sandwich Joint Testing  

NASA Technical Reports Server (NTRS)

Testing of composite sandwich joint elements has been completed to verify the strength capacity of joints designed to carry specified running loads representative of a high speed civil transport wing. Static tension testing at both room and an elevated temperature of 350 F and fatigue testing at room temperature were conducted to determine strength capacity, fatigue life, and failure modes. Static tension test results yielded failure loads above the design loads for the room temperature tests, confirming the ability of the joint concepts tested to carry their design loads. However, strength reductions as large as 30% were observed at the elevated test temperature, where all failure loads were below the room temperature design loads for the specific joint designs tested. Fatigue testing resulted in lower than predicted fatigue lives.

Walker, Sandra P.

1998-01-01

41

A finite element overlay technique for modeling pinned composite joints  

NASA Technical Reports Server (NTRS)

A finite element technique using overlaid plane stress elements is presented for modeling a pinned composite joint. The technique allows for discrete modeling of the pin and web regions of the joint in a two-dimensional (2-D) finite element analysis. Thus, predictive capability is substantially increased without the added complexity of a three-dimensional (3-D) analysis. The overlay technique requires a thorough evaluation of the model constraints between the joint components. Bearing panels are used to account for a reduced compressive modulus under bearing loads. Application of the plane stress overlay technique to the Filament Wound Case (FWC) Program is discussed. The experimental approach to determine bearing panel moduli using a double lap shear test is detailed, and finite element results are correlated with full-scale FWC joint test results.

Colvin, G. E.; Adams, D. S.

1986-01-01

42

Hot melt joints for carbon fibre reinforced composites  

Microsoft Academic Search

The electric conductivity of carbon fibers and EVA thermoplastic adhesives in composite materials are exploited in a method for melting and\\/or hardening joint bonds. The joining method is based on the simultaneous use of electrical energy and mechanical pressure in joining sections of CFRP materials by means of hot melts. The EVA hot melt is used as a model adhesive

C. Netze; W. Michaeli

1990-01-01

43

Thermally Conductive Metal-Tube/Carbon-Composite Joints  

NASA Technical Reports Server (NTRS)

An improved method of fabricating joints between metal and carbon-fiber-based composite materials in lightweight radiators and heat sinks has been devised. Carbon-fiber-based composite materials have been used in such heat-transfer devices because they offer a combination of high thermal conductivity and low mass density. Metal tubes are typically used to carry heat-transfer fluids to and from such heat-transfer devices. The present fabrication method helps to ensure that the joints between the metal tubes and the composite-material parts in such heat-transfer devices have both (1) the relatively high thermal conductances needed for efficient transfer of heat and (2) the flexibility needed to accommodate differences among thermal expansions of dissimilar materials in operation over wide temperature ranges. Techniques used previously to join metal tubes with carbon-fiber-based composite parts have included press fitting and bonding with epoxy. Both of these prior techniques have been found to yield joints characterized by relatively high thermal resistances. The present method involves the use of a solder (63 percent Sn, 37 percent Pb) to form a highly thermally conductive joint between a metal tube and a carbon-fiber-based composite structure. Ordinarily, the large differences among the coefficients of thermal expansion of the metal tube, solder, and carbon-fiber-based composite would cause the solder to pull away from the composite upon post-fabrication cooldown from the molten state. In the present method, the structure of the solder is modified (see figure) to enable it to deform readily to accommodate the differential thermal expansion.

Copeland, Robert J.

2004-01-01

44

Tensile strength of simulated and welded butt joints in W-Cu composite sheet  

NASA Technical Reports Server (NTRS)

The weldability of W-Cu composite sheet was investigated using simulated and welded joints. The welded joints were produced in a vacuum hot press. Tensile test results showed that simulated joints can provide strength and failure mode data which can be used in joint design for actual weldments. Although all of the welded joints had flaws, a number of these joints were as strong as the W-Cu composite base material.

Moore, Thomas J.; Watson, Gordon K.

1994-01-01

45

Resistance welding of thermoplastic composites skin\\/stringer joints  

Microsoft Academic Search

An experimental investigation of resistance welding of APC-2\\/AS4 PEEK\\/carbon fibre composite using a stainless steel mesh heating element is presented. A special specimen geometry, the skin\\/stringer configuration, was used to represent a typical reinforced aerospace structural joint. The specimens consisted of a flange, representing a stringer or frame, welded onto a skin laminate. The effects of the welding parameters such

M. Dubé; P. Hubert; A. Yousefpour; J. Denault

2007-01-01

46

ElastoPlastic Failure Analysis of Composite Bolted Joints  

Microsoft Academic Search

An elasto-plastic finite element analysis of pin loaded joints in laminated composites has been investigated and comparisons made with both existing 2-D linear elastic plane stress analytical solutions and experimental results for a graphite\\/epoxy laminate. The finite element analysis included nonlinear material behavior after initial failure by assuming an elastic-perfectly plastic bimodular material model. Laminated plate theory was used to

Yoshifumi Tsujimoto; Dale Wilson

1986-01-01

47

Bonded joint strength - Static versus fatigue  

NASA Technical Reports Server (NTRS)

Adhesives are commonly characterized only by their static strength even though they are used in structural joints that are subjected to fatigue loads. This paper reviews the relationship between static and fatigue strength for four different specimen types: single-lap-shear, edge-delamination, double cantilever beam, and cracked-lap-shear. It was found that the ratio of static strength to fatigue strength varied from 2.3 to 4.7, depending on the adhesive and specimen configuration.

Johnson, W. S.; Mall, S.

1984-01-01

48

Effect of Composite Substrates on the Mechanical Behavior of Brazed Joints in Metal-Composite System  

NASA Technical Reports Server (NTRS)

Advanced composite components are being considered for a wide variety of demanding applications in aerospace, space exploration, and ground based systems. A number of these applications require robust integration technologies to join dissimilar materials (metalcomposites) into complex structural components. In this study, three types of composites (C-C, C-SiC, and SiC-SiC) were vacuum brazed to commercially pure Ti using the active metal braze alloy Cusil-ABA (63Ag-35.3Cu-1.75Ti). Composite substrates with as fabricated and polished surfaces were used for brazing. The microstructure and composition of the joint, examined using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), showed sound metallurgical bonding in all systems. The butt strap tensile (BST) test was performed on bonded specimens at room and elevated temperatures. Effect of substrate composition, interlaminar properties, and surface roughness on the mechanical properties and failure behavior of joints will be discussed.

Singh, M.; Morscher, Gregory N.; Shpargel, Tarah; Asthana, Rajiv

2006-01-01

49

One-step brazing process to join CFC composites to copper and copper alloy  

NASA Astrophysics Data System (ADS)

The aim of this work is to develop a new single-step brazing technique to join carbon fibre reinforced carbon composite (CFC) to pure copper (Cu) and copper alloy (CuCrZr) for nuclear fusion applications. In order to increase the wettability of CFC by a copper-based brazing alloy containing no active metal, the composite surface was modified by direct reaction with chromium, which forms a carbide layer and allows a large reduction of the contact angle. After the CFC surface modification, the commercial Gemco ® alloy (Cu/Ge) was successfully used to braze CFC to pure copper and pure copper to CuCrZr by the same heat treatment. The shear strength of the CFC/Cu joints measured by single lap shear tests at room temperature was (34 ± 4) MPa, comparable to the values obtained by other joining processes and higher than the intrinsic CFC shear strength.

Salvo, Milena; Casalegno, Valentina; Rizzo, Stefano; Smeacetto, Federico; Ferraris, Monica; Merola, Mario

2008-02-01

50

Ultrasonic inspection of adhesive joints of composite pipelines  

NASA Astrophysics Data System (ADS)

Composite pipelines are an attractive solution when traditional materials are not suitable for this purpose, which happens frequently at aggressive environments and also where the structural weight is a limiting factor. This work studies the application of the ultrasonic technique at the detection of defects as lack of adhesive and lack of adhesion, commonly found in adhesive joints of glass fiber reinforced plastic (GFRP) pipelines applied at onshore and offshore facilities. Computational simulations were conducted in CIVA 11software (beta version) in order to obtain the best possible configuration for the inspections, applying the pulse-echo technique. Experimental results were compared to these simulations and several transducers were tested. An inspection methodology and reference blocks were developed for the calibration of the inspections. Some samples were selected for cutting in order to compare the ultrasonic results and the real condition of the joints. Results show that smaller frequencies are suitable for the inspection of this material and focused probes present more accurate results.

de Almeidaa, Priscila Duarte; Alcoforado Rebello, João Marcos; Pereira, Gabriela Ribeiro; Soares, Sérgio Damasceno; Fernandez, Roman

2014-02-01

51

Some characteristics of friction welded joints between particulate alumina composite material and 6061 aluminium alloy  

Microsoft Academic Search

Friction welded joints were made with 6061 aluminium alloy and aluminium alloy composite material (MMC) containing 16.1% vol. dispersed particulate alumina and the structures and mechanical properties of these joints were examined.For a short friction time the heat affected zone of a joint was formed almost parallel to the weld interface; however, with increasing friction time it became shaped like

K. Katoh; H. Tokisue

1997-01-01

52

Electrical properties of superconducting joint between composite conductors  

Microsoft Academic Search

To investigate the electrical properties of the joint between superconducting multifilamentary wires, the authors used a radio-frequency superconducting quantum interference device (RF-SQUID) voltmeter to measure the extremely small voltage induced across the joint. They measured the time variation of both the current induced in a loop of superconducting wire and the voltage induced across the joint. A voltage sensitivity in

T. Tominaka; S. Kakugawa; N. Hara; N. Maki

1991-01-01

53

Application of Pi Preform Composite Joints in Fabrication of NASA Composite Crew Module Demonstration Structure  

NASA Technical Reports Server (NTRS)

This paper will describe unique and extensive use of pre-woven and impregnated pi cross-sections in fabrication of a carbon composite demonstration structure for the Composite Crew Module (CCM) Program. The program is managed by the NASA Safety and Engineering Center with participants from ten NASA Centers and AFRL. Multiple aerospace contractors are participating in the design development, tooling and fabrication effort as well. The goal of the program is to develop an agency wide design team for composite habitable spacecraft. The specific goals for this development project are: a) To gain hands on experience in design, building and testing a composite crew module. b) To validate key assumptions by resolving composite spacecraft design details through fabrication and testing of hardware. This paper will focus on the design and fabrication issues supporting selection of the Lockheed Martin patented Pi pre-form to provide sound composite joints a numerous locations in the structure. This abstract is based on Preliminary Design data. The final design will continue to evolve through the fall of 2007 with fabrication mostly completed by conference date.

Higgins, John E.; Pelham, Larry

2008-01-01

54

Ultrasonic guided wave monitoring of composite bonded joints using macro fiber composite transducers  

NASA Astrophysics Data System (ADS)

The monitoring of adhesively-bonded joints through the use of ultrasonic guided waves is the general topic of this paper. Specifically, composite-to-composite joints representative of the wing skin-to-spar bonds of Unmanned Aerial Vehicles (UAVs) are examined. This research is the first step towards the development of an on-board structural health monitoring system for UAV wings based on integrated ultrasonic sensors. The study investigates two different lay-ups for the wing skin and two different types of bond defects, namely poorly-cured adhesive and disbonded interfaces. The guided wave propagation problem is studied numerically by a semi-analytical finite element method that accounts for viscoelastic damping, and experimentally by utilizing macro fiber composite (MFC) transducers which are inexpensive, flexible, highly robust, and viable candidates for application in on-board monitoring systems. Based upon change in energy transmission, the presence of damage is successfully identified through features extracted in both the time domain and discrete wavelet transform domain. A unique "passive" version of the diagnostic system is also demonstrated experimentally, whereby MFC sensors are utilized for detecting and locating simulated active damage in an aluminum plate. By exploiting the directivity behavior of MFC sensors, a damage location algorithm which is independent of wave speed is developed. Application of this approach in CFRP components may alleviate difficulties associated with damage location in highly anisotropic systems.

Matt, Howard; Bartoli, Ivan; Coccia, Stefano; Lanza di Scalea, Francesco; Oliver, Joseph; Kosmatka, John; Park, Gyuhae; Farrar, Charles

2006-03-01

55

Thermal Effects on the Bearing Behavior of Composite Joints  

NASA Technical Reports Server (NTRS)

Thermal effects on the pin-bearing behavior of an IM7/PET15 composite laminate are studied comprehensively. A hypothesis presents factors influencing a change in pin-bearing strength with a change in temperature for a given joint design. The factors include the change in the state of residual cure stress, the material properties, and the fastener fit with a change in temperature. Experiments are conducted to determine necessary lamina and laminate material property data for the IM7/PET15 being utilized in this study. Lamina material properties are determined between the assumed stress free temperature of 460 F down to -200 F. Laminate strength properties are determined for several lay-ups at the operating temperatures of 350 F, 70 F, and -200 F. A three-dimensional finite element analysis model of a composite laminate subject to compressive loading is developed. Both the resin rich layer located between lamina and the thermal residual stresses present in the laminate due to curing are determined to influence the state of stress significantly. Pin-bearing tests of several lay-ups were conducted to develop an understanding on the effect of temperature changes on the pin-bearing behavior of the material. A computational study investigating the factors influencing pin-bearing strength was performed. A finite element model was developed and used to determine the residual thermal cure stresses in the laminate containing a hole. Very high interlaminar stress concentrations were observed two elements away from the hole boundary at all three operating temperatures. The pin-bearing problem was modeled assuming a rigid frictionless pin and restraining only radial displacements at the hole boundary. A uniform negative pressure load was then applied to the straight end of the model. A solution, where thermal residual stresses were combined with the state of stress due to pin-bearing loads was evaluated. The presence of thermal residual stresses intensified the interlaminar stresses predicted at the hole boundary in the pin-bearing problem. This dissertation shows that changes in material properties drives pin-bearing strength degradation with increasing temperature.

Walker, Sandra Polesky

2001-01-01

56

Post-Failure Analysis of Bolted Composite Joints in Tension or Shear-Out Mode Failure  

Microsoft Academic Search

A progressive damage model was developed for bolted joints in laminated composites which may fail in either tension mode or shear-out mode. The model is capable of assess ing damage accumulated in laminates with arbitrary ply orientations during mechanical loading and of predicting the ultimate strength of the joints which failed in tension or shear-out mode. The model consists of

Fu-Kuo Chang; Kuo-Yen Chang

1987-01-01

57

Buckling-driven debonding in stiff block: compliant joint structural assemblies patched with composite materials  

Microsoft Academic Search

The initiation, growth, and stability of buckling driven debonding in structural assemblies of stiff blocks, compliant joints,\\u000a and adhesively bonded composite layers are analytically investigated. The model is developed with focus on masonry walls externally\\u000a strengthened with composite materials where static and, mainly, dynamic loads may induce compression in the strengthening\\u000a layers triggering a buckling driven debonding near the joints.

Oded Rabinovitch

2010-01-01

58

Variation in joint fluid composition and its effect on the tribology of replacement joint articulation  

E-print Network

Polyethylene wear is a significant clinical problem limiting the long-term survival of joint replacement prostheses, particularly in total hip arthroplasty (THA) and total knee arthroplasty (TKA). Although the tribology ...

Mazzucco, Daniel Clarke, 1976-

2003-01-01

59

Microstructure and Mechanical Properties of Joints in Sintered SiC Fiber-Bonded Ceramics Brazed with Ag-Cu-Ti Alloy  

SciTech Connect

Active metal brazing of a new high thermal conductivity sintered SiC-polycrystalline fiber-bonded ceramic (SA-Tyrannohex{reg_sign}) has been carried out using a Ti-containing Ag-Cu active braze alloy (Cusil-ABA{reg_sign}). The brazed composite joints were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS). The results show that this material can be successfully joined using judiciously selected off-the shelf active braze alloys to yield metallurgically sound joints possessing high integrity. Uniform and continuous joints were obtained irrespective of differences in the fiber orientation in the substrate material. Detailed interfacial microanalysis showed that the titanium reacts with C and Si to form TiC layer and a Ti-Si compound, respectively. Furthermore, the evaluation of shear strength of the joints was also conducted at ambient and elevated temperatures in air using the single-lap offset (SLO) shear test. The perpendicular-type SA-Tyrannohex joints exhibited apparent shear strengths of about 42 MPa and 25 MPa at 650 C and 750 C, respectively. The fracture at the higher temperature occurred at the interface between the reaction-formed TiC layer and braze. This might be caused by generation of stress intensity when a shear stress was applied, according to {mu}-FEA simulation results.

Singh, Mrityunjay [NASA-Glenn Research Center, Cleveland; Matsunaga, Tadashi [ORNL; Lin, Hua-Tay [ORNL; Asthana, Rajiv [University of Wisconsin-Stout, Menomonie; Ishikawa, Toshihiro [Ube Industries, Ltd.

2012-01-01

60

Microstructure and mechanical properties of joints in sintered SiC fiber-bonded ceramics brazed with Ag Cu Ti alloy  

SciTech Connect

Active metal brazing of a new high thermal conductivity sintered SiC-polycrystalline fiber-bonded ceramic (SA-Tyrannohexs) has been carried out using a Ti-containing Ag Cu active braze alloy (Cusil-ABAs). The brazed composite joints were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM EDS). The results show that this material can be successfully joined using judiciously selected off-the shelf active braze alloys to yield metallurgically sound joints possessing high integrity. Uniform and continuous joints were obtained irrespective of differences in the fiber orientation in the substrate material. Detailed interfacial microanalysis showed that the titanium reacts with C and Si to form TiC layer and a Ti Si compound, respectively. Furthermore, the evaluation of shear strength of the joints was also conducted at ambient and elevated temperatures in air using the single-lap offset (SLO) shear test. The perpendicular-type SA-Tyrannohex joints exhibited apparent shear strengths of about 42 MPa and 25 MPa at 650 1C and 750 1C, respectively. The fracture at the higher temperature occurred at the interface between the reactionformed TiC layer and braze. This might be caused by generation of stress intensity when a shear stress was applied, according to m-FEA simulation results.

Singh, Mrityunjay [NASA-Glenn Research Center, Cleveland; Asthana, Rajiv [University of Wisconsin-Stout, Menomonie; Ishikawa, Toshihiro [Ube Industries, Ltd.; Matsunaga, Tadashi [Ube Industries, Ltd.; Lin, Hua-Tay [ORNL

2012-01-01

61

Structural testing of the North Wind 250 composite rotor joint  

SciTech Connect

The North Wind 250 wind turbine is under development at Northern Power Systems (NPS) in Moretown, VT. The turbine uses a unique, flow-through, teetered-rotor design. This design eliminates structural discontinuities at the blade/hub interface by fabricating the rotor as one continuous structural element. To accomplish this, the two blade spars are joined at the center of the rotor using a proprietary bonding technique. Fatigue tests were conducted on the full-scale rotor joint at the National Renewable Energy Laboratory (NREL). Subsequent tests are now underway to test the full-scale rotor and hub assembly to verify the design assumptions. The test articles were mounted in dedicated test fixtures. For the joint test, a constant moment was generated across the joint and parent material. Hydraulic actuators applied sinusoidal loading to the test article at levels equivalent to 90% of the extreme wind load for over one million cycles. When the loading was increased to 112% of the extreme wind load, the joint failed by buckling. Strain levels were monitored at 14 locations inside and outside of the blade joint during the test. The tests were used to qualify this critical element of the rotor for field testing and to provide information needed to improve the structural design of the joint.

Musial, W; Link, H [National Renewable Energy Lab., Golden, CO (United States); Coleman, C [Northern Power Systems, Moretown, VT (United States)

1994-05-01

62

Co-cured composite joint strength investigation based on behavior characterization of the [0\\/ (+\\/-)theta\\/90]s family  

Microsoft Academic Search

Joints provide a path for transfer of load and are important components in an assembly of structures, particularly in translating joint strength improvements directly to significant cost savings. These cost savings are more evident in composite joints since manufacturing of more complex single piece components results in a reduction of both part count and labor. An improvement in joint strength

Xinyuan Tan

2008-01-01

63

Investigation of Adhesively Bonded Joints for Composite Propeller Shafts  

Microsoft Academic Search

Substituting composite structures for conventional metallic structures has many advantages because of higher specific stiffness and specific strength of composite materials. In this work, one-piece propeller shafts composed of carbon\\/epoxy composites were designed and manufactured for a rear wheel drive automobile satisfying three design specifications, such as static torque transmission capability, torsional buckling and the fundamental natural bending frequency. Single

Jin Kook Kim; Dai Gil Lee; Durk Hyun Cho

2001-01-01

64

Experimental determination of the effects of moisture on composite-to-composite adhesive joints  

NASA Technical Reports Server (NTRS)

The primary mode of moisture ingress into bonded composite joints is determined using a nuclear probe for deuterium (NPD) to measure the localized D2O content along the length of the adhesive (FM-300 and EA-9601) and through the thickness of bonded composite speciments. Calculated diffusivities and NPD measured equilibrium moisture contents are used to predict the moisture profiles along the length of the adhesives as a function of exposure time, temperature, and relative humidity. These results are compared with the observed moisture profiles to evaluate the extent of enhanced edge diffusion. The FM-300 adhesive exhibits good agreement between measured and predicted profiles at 49 C, 70% and 90% RH, and 77 C, 70% RH. At 77 C, 90% RH, the measured moisture content near the adhesive edge is substantially larger than the predicted level. The EA-9601 adhesive also shows good agreement at 49 C, 70% and 90% RH, but at 77 C, the concentration of D20 near the edges is enhanced at each humidity level. The effect of moisture content on the bond shear strength at room temperature and at elevated temperature is evaluated.

Deiasi, R. J.; Schulte, R. L.

1981-01-01

65

Fluxless non-eutectic joints fabricated using gold-tin multilayer composite  

Microsoft Academic Search

Fluxless bonding processes using two different noneutectic gold-tin (Au-Sn) multilayer composites to fabricate high quality solder joints have been successfully achieved. In contrast to the well-known eutectic solders of 80 wt. % Au and 20 wt. % Sn commonly selected by the packaging industry, we have adopted a substantially cost-effective strategy by purposely designing and constructing our solder joints to

Chin C. Lee; Ricky W. Chuang

2003-01-01

66

Lamb wave propagation in Z-pin reinforced co-cured composite pi-joints  

NASA Astrophysics Data System (ADS)

This paper presents an initial study on Lamb wave propagation characteristics in z-pin reinforced, co-cured composite pi-joints for the purposes of structural health monitoring (SHM). Pi-joint test articles were designed and created to replicate a co-cured, all composite skin-spar joint found within a typical aircraft wing structure. Because pi-joints exhibit various complex damage modes, formal studies are required if SHM systems are to be developed to monitor these types of joints for potential damage. Experiments were conducted on a undamaged (healthy) and damaged test articles where Lamb waves were excited using one lead zirconate titanate (PZT) transducer. A three-dimensional (3D) scanning laser Doppler vibrometer (LDV) was used to collect high-density scans of both the in-plane and out-of-plane velocity measurements. In the damaged test article, where delamination, matrix cracking, and fiber breakage can clearly be seen, changes in both the fundamental antisymmetric A0 and symmetric S0 Lamb wave modes are apparent. In both test articles, the effects of narrow geometry, discontinuity due to the attachment of the web, and thickness has detectable effects on Lamb wave propagation. From the comparisons between Lamb waves propagating through the undamaged and damaged test articles, it is clear that damage can be detected using Lamb waves in z-pin reinforced, co-cured composite pi-joints for this case of extensive damage.

Swenson, Eric D.; Soni, Som R.; Kapoor, Hitesh

2010-04-01

67

Laser ablation assisted adhesive bonding of automotive structural composites  

SciTech Connect

Laser ablation has been evaluated as a surface pretreatment prior to adhesive bonding. In prior experimental work, it was observed that when adhesively bonded, composite, single lap shear samples fail, the fracture often occurs at either the adhesive/adherend interface or in the resin rich surface layer of the composite. These two areas represent the weakest portion of the joint. Laser ablation pretreatment generates areas where the resin on the composite surface is selectively removed leaving behind exposed reinforcing fibers which are the major load bearing members of the composite. In a subsequent adhesive bonding operation, this allows portions of the fibers to be encapsulated in the adhesive while other portions of the fiber remain in the composite resin. This type of pretreatment permits fibers to bridge and reinforce the interface between adhesive and adherend. A secondary benefit is the removal of surface contaminantes by pyrolysis. Microscopic observation of laser ablated surfaces indicates a prominent, fiber rich area. Results of the mechanical evaluation indicated that the lap shear strength for laser ablated samples was significantly higher than specimens with no pretreatment or with solvent cleaning only, but were slightly lower than specimens that were mechanically roughened and cleaned with solvents prior to bonding.

Boeman, R.G.; Paulauskas, F.L.; Warren, C.D.

1999-07-03

68

Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results  

NASA Technical Reports Server (NTRS)

A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

Bunin, Bruce L.; Sagui, R. L.

1985-01-01

69

Time-temperature effect in adhesively bonded joints  

NASA Technical Reports Server (NTRS)

The viscoelastic analysis of an adhesively bonded lap joint was reconsidered. The adherends are approximated by essentially Reissner plates and the adhesive is linearly viscoelastic. The hereditary integrals are used to model the adhesive. A linear integral differential equations system for the shear and the tensile stress in the adhesive is applied. The equations have constant coefficients and are solved by using Laplace transforms. It is shown that if the temperature variation in time can be approximated by a piecewise constant function, then the method of Laplace transforms can be used to solve the problem. A numerical example is given for a single lap joint under various loading conditions.

Delale, F.; Erdogan, F.

1981-01-01

70

Particle fracture in metal-matrix composite friction joints  

Microsoft Academic Search

The influence of welding parameters, reinforcing particle chemistry and shape, matrix condition and silver interlayers on\\u000a particle fracture during similar and dissimilar friction welding of aluminium-based metal-matrix composite (MMC) base material\\u000a was investigated. Two composite base materials were examined, one containing Al2O3 particles and the other containing 72 wt% Al2O3–7 wt % Fe2O3–17 wt % SiO2–3 wt % TiO2 particles.

C. MALDONADO; T. H North

1997-01-01

71

Engineered Cementitious Composite May Replace Bridge Deck Joints  

E-print Network

of the same components as traditional portland cement concrete (including cement, aggregate, wa- ter and fly in three phases, starting in the lab, moving to the field, and then working to make improvements. continued Decks Based on Strain-Hardening Cementitious Composites--Phase 3: Shrinkage Control Start Date: July

Li, Victor C.

72

SIMULATION OF PROGRESSIVE DAMAGE IN BOLTED COMPOSITE JOINTS  

Microsoft Academic Search

Recently, a continuum based progressive damage model for fiber-reinforced composites became available in the commercial finite element code ABAQUS. The implemented model uses the Hashin damage initiation criteria (1,2) and damage evolution is based on the work of Matzenmiller (3) and Camanho and Davila (4). The \\

Hannes Koerber; Pedro P. Camanho

73

An Investigation of the Tensile Strength of a Composite-To-Metal Adhesive Joint  

NASA Astrophysics Data System (ADS)

The present study examines the feasibility of a simple concept composite-to-metal butt joint through the performance of both numerical and experimental studies. The composite part is made of glass/epoxy unidirectional layers made with the vacuum bag method. The geometry of the joint is typical for marine applications and corresponds to a low stiffness ratio. Two major parameters are investigated, namely the overlap length and the surface preparation of the steel adherent. Manufacturing of specimens and the procedure of the tensile tests are described in detail, giving hints for obtaining a better quality joint. Axial elongation and strains at various places of the joint were monitored and also numerically calculated. The tests revealed that the joint is quite effective, irrespectively of the steel surface preparation method. The failure loads are comparable and in some cases superior to other corresponding values found in the literature. The numerical models proved to adequately predict the structural response of the joint up to the loading where debonding starts.

Tsouvalis, Nicholas G.; Karatzas, Vassilios A.

2011-04-01

74

Structural Performance Evaluation of Composite-To-Steel Weld Bonded Joint  

SciTech Connect

The Automotive Composites Consortium (ACC), a collaboration of Chrysler, Ford, General Motors, and the US Department of Energy is conducting a focal project to demonstrate the use of composite materials in high volume structural applications such as an underbody capable of carrying crash loads. One of the critical challenges is to attach the composite part to the steel structure in a high-volume automotive manufacturing environment and meet the complex requirements for crash. Weld-bonding, a combination of adhesive bonding and spot welding, was selected as the primary joining method. A novel concept of bonding doubler steel strips to composite enabled the spot welding to the steel structure, ensuring the compability with the OEM assembly processes. The structural performance of the joint, including durability, was assessed via analytical and physical testing under quasi-static loading at various temperatures. This paper discusses the results of the experiments designed to generate key modeling parameters for Finite Element Analysis of the joint.

Shah, Bhavesh [General Motors Corporation-R& D; Frame, Barbara J [ORNL; Dove, Caroline [ACC, USCAR; Fuchs, Hannes [Multimatic Engineering

2010-01-01

75

Effect of bond thickness on fracture and fatigue strength of adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

An experimental investigation of composite to composite bonded joints was undertaken to study the effect of bond thickness on debond growth rate under cyclic loading and critical strain energy release rate under static loading. Double cantilever beam specimens of graphite/epoxy adherends bonded with EC 3445 were tested under mode I loading. A different behavior of fracture and fatigue strength was observed with variation of bondline thickness.

Mall, S.; Ramamurthy, G.

1989-01-01

76

Fabrication and Testing of Durable Redundant and Fluted-Core Joints for Composite Sandwich Structures  

NASA Technical Reports Server (NTRS)

The development of durable bonded joint technology for assembling composite structures is an essential component of future space technologies. While NASA is working toward providing an entirely new capability for human space exploration beyond low Earth orbit, the objective of this project is to design, fabricate, analyze, and test a NASA patented durable redundant joint (DRJ) and a NASA/Boeing co-designed fluted-core joint (FCJ). The potential applications include a wide range of sandwich structures for NASA's future launch vehicles. Three types of joints were studied -- splice joint (SJ, as baseline), DRJ, and FCJ. Tests included tension, after-impact tension, and compression. Teflon strips were used at the joint area to increase failure strength by shifting stress concentration to a less sensitive area. Test results were compared to those of pristine coupons fabricated utilizing the same methods. Tensile test results indicated that the DRJ design was stiffer, stronger, and more impact resistant than other designs. The drawbacks of the DRJ design were extra mass and complex fabrication processes. The FCJ was lighter than the DRJ but less impact resistant. With barely visible but detectable impact damages, all three joints showed no sign of tensile strength reduction. No compression test was conducted on any impact-damaged sample due to limited scope and resource. Failure modes and damage propagation were also studied to support progressive damage modeling of the SJ and the DRJ.

Lin, Shih-Yung; Splinter, Scott C.; Tarkenton, Chris; Paddock, David A.; Smeltzer, Stanley S.; Ghose, Sayata; Guzman, Juan C.; Stukus, Donald J.; McCarville, Douglas A.

2013-01-01

77

Static and Fatigue Strength Evaluations for Bolted Composite/Steel Joints for Heavy Vehicle Chassis Components  

SciTech Connect

In May 2003, ORNL and PNNL began collaboration on a four year research effort focused on developing joining techniques to overcome the technical issues associated with joining lightweight materials in heavy vehicles. The initial focus of research is the development and validation of joint designs for a composite structural member attached to a metal member that satisfy the structural requirements both economically and reliably. Huck-bolting is a common joining method currently used in heavy truck chassis structures. The initial round of testing was conducted to establish a performance benchmark by evaluating the static and fatigue behavior of an existing steel/steel chassis joint at the single huck-bolt level. Both tension and shear loading conditions were considered, and the resulting static and fatigue strengths will be used to guide the joint design for a replacement composite/steel joint. A commercially available, pultruded composite material was chosen to study the generic issues related to composite/steel joints. Extren is produced by STRONGWELL, and it is a combination of fiberglass reinforcement and thermosetting polyester or vinyl ester resin systems. Extren sheets of 3.2 mm thick were joined to 1.4 mm SAE1008 steel sheets with a standard grade 5 bolt with 6.35 mm diameter. Both tension and shear loading modes were considered for the single hybrid joint under static and fatigue loading conditions. Since fiberglass reinforced thermoset polymer composites are a non-homogenous material, their strengths and behavior are dependent upon the design of the composite and reinforcement. The Extren sheet stock was cut along the longitudinal direction to achieve maximum net-section strength. The effects of various manufacturing factors and operational conditions on the static and fatigue strength of the hybrid joint were modeled and experimentally verified. It was found that loading mode and washer size have significant influence on the static and fatigue strength of the hybrid joint. The effect of different fatigue test frequencies on the sample temperature and the resulting fatigue life was also examined.

Sun, Xin; Stephens, Elizabeth V.; Herling, Darrell R.

2004-09-14

78

Measurement of damping of graphite epoxy composite materials and structural joints  

NASA Technical Reports Server (NTRS)

The damping capacity of graphite epoxy materials and structural joints was evaluated. The damping ratio of different composite specimens and bonded joints were systematically evaluated under normal atmospheric conditions and in a vacuum environment. Free and forced vibration test methods were employed for measuring the damping ratios. The effect of edge support conditions on the damping value of a composite tube specimen was studied by using a series of experiments performed on the specimen with different edge supports. It was found that simulating a free-free boundary conditions by having no constraints at the ends gives the lowest value of the material damping of the composite. The accuracy of the estimation of the damping ratio value was improved by using a curve-fitting technique on the response data obtained through measurement. The effect of outgassing (moisture desorption) on the damping capacity was determined by measuring the damping ratio of the tube specimen in a vacuum environment before and after outgassing had occurred. The effects of high and low temperatures on the damping was also investigated by using a series of experiments on tube and beam specimens. An analytical model to study the vibrations of a bonded lap joint system was formulated. Numerical results were generated for different overlap ratios of the system. These were compared with experimental results. In order to determine the influence of bonded joints on the material damping capacity, experiments were conducted on bonded lap-jointed and double-butt-jointed specimens. These experimental results were compared with simple beam specimens with no joints.

Crocker, Malcolm J.; Rao, Mohan D.; Raju, P. K.; Yan, Xinche

1989-01-01

79

Fatigue analysis of thin AlMgSi welded joints under constant and variable amplitude block loadings  

Microsoft Academic Search

This paper reports the fatigue behaviour of thin AlMgSi1 aluminium alloy weldments and the improvement in fatigue strength due to post-weld treatments. Several fatigue tests were performed using two distinct types of thin welded joints, T and single lap, manufactured using a 6xxx series aluminium alloy, and the efficiency of fatigue life improvement techniques, such as post-weld heat treatment and

J. A. M Pinho-da-Cruz; J. A. M Ferreira; J. D. M Costa; L. F. P Borrego

2003-01-01

80

Disbond monitoring in adhesive joints using shear stress optical fiber sensors  

NASA Astrophysics Data System (ADS)

We present dedicated shear stress optical fiber sensors for in situ disbond monitoring of adhesive bonds. The shear stress sensitivity of these sensors is about 60 pm MPa-1, which corresponds to a shear strain sensing resolution of 50 ??. By integrating a combination of three such sensors in the adhesive bond line of a single lap joint, we can assess the internal shear stress distribution when the joint is tensile loaded. Disbonding of this joint was initiated by cyclic tensile loading, and the sensor responses were monitored during this process. Our results show that this sensing system can detect disbonds as small as 100 ?m.

Sulejmani, Sanne; Sonnenfeld, Camille; Geernaert, Thomas; Luyckx, Geert; Mergo, Pawel; Urbanczyk, Waclaw; Chah, Karima; Thienpont, Hugo; Berghmans, Francis

2014-07-01

81

Loading Analysis of Composite Wind Turbine Blade for Fatigue Life Prediction of Adhesively Bonded Root Joint  

NASA Astrophysics Data System (ADS)

Nowadays wind energy is widely used as a non-polluting cost-effective renewable energy resource. During the lifetime of a composite wind turbine which is about 20 years, the rotor blades are subjected to different cyclic loads such as aerodynamics, centrifugal and gravitational forces. These loading conditions, cause to fatigue failure of the blade at the adhesively bonded root joint, where the highest bending moments will occur and consequently, is the most critical zone of the blade. So it is important to estimate the fatigue life of the root joint. The cohesive zone model is one of the best methods for prediction of initiation and propagation of debonding at the root joint. The advantage of this method is the possibility of modeling the debonding without any requirement to the remeshing. However in order to use this approach, it is necessary to analyze the cyclic loading condition at the root joint. For this purpose after implementing a cohesive interface element in the Ansys finite element software, one blade of a horizontal axis wind turbine with 46 m rotor diameter was modelled in full scale. Then after applying loads on the blade under different condition of the blade in a full rotation, the critical condition of the blade is obtained based on the delamination index and also the load ratio on the root joint in fatigue cycles is calculated. These data are the inputs for fatigue damage growth analysis of the root joint by using CZM approach that will be investigated in future work.

Salimi-Majd, Davood; Azimzadeh, Vahid; Mohammadi, Bijan

2014-07-01

82

Delamination-Debond Behaviour of Composite T- Joints in Wind Turbine Blades  

NASA Astrophysics Data System (ADS)

Wind turbine industry utilizes composite materials in turbine blade structural designs because of their high strength/stiffness to weight ratio. T-joint is one of the design configurations of composite wind turbine blades. T-joints consist of a skin panel and a stiffener co-bonded or co-cured together with a filler material between them. T-joints are prone to delaminations between skin/stiffener plies and debonds between skin-stiffener-filler interfaces. In this study, delamination/debond behavior of a co-bonded composite T-joint is investigated under 0° pull load condition by 2D finite element method. Using Abaqus® commercial FE software, zero-thickness cohesive elements are used to simulate delamination/debond in ply interfaces and bonding lines. Pulling load at 0° is applied and load-displacement behavior and failure scenario are observed. The failure sequence consists of debonding of filler/stringer interface during one load drop followed by a second drop in which the 2nd filler/stringer debonds, filler/skin debonding and skin delamination leading to total loss of load carrying capacity. This type of failure initiation has been observed widely in the literature. When the debond strength is increased 30%, failure pattern is found to change in addition to increasing the load capacity by 200% before total loss of loading carrying capacity occurs. Failure initiation and propagation behavior, initial and max failure loads and stress fields are affected by the property change. In all cases mixed-mode crack tip loading is observed in the failure initiation and propagation stages. In this paper, the detailed delamination/debonding history in T-joints is predicted with cohesive elements for the first time.

Gulasik, H.; Coker, D.

2014-06-01

83

Ultrasonic guided wave monitoring of composite wing skin-to-spar bonded joints in aerospace structures  

NASA Astrophysics Data System (ADS)

The monitoring of adhesively bonded joints by ultrasonic guided waves is the general topic of this paper. Specifically, composite-to-composite joints representative of the wing skin-to-spar bonds of unmanned aerial vehicles (UAVs) are examined. This research is the first step towards the development of an on-board structural health monitoring system for UAV wings based on integrated ultrasonic sensors. The study investigates two different lay-ups for the wing skin and two different types of bond defects, namely poorly cured adhesive and disbonded interfaces. The assessment of bond state is based on monitoring the strength of transmission through the joints of selected guided modes. The wave propagation problem is studied numerically by a semi-analytical finite element method that accounts for viscoelastic damping, and experimentally by ultrasonic testing that uses small PZT disks preferably exciting and detecting the single-plate s0 mode. Both the models and the experiments confirm that the ultrasonic energy transmission through the joint is highly dependent on the bond conditions, with defected bonds resulting in increased transmission strength. Large sensitivity to the bond conditions is found at mode coupling points, as a result of the large interlayer energy transfer.

Matt, Howard; Bartoli, Ivan; Lanza di Scalea, Francesco

2005-10-01

84

Design, fabrication, installation and flight service evaluation of a composite cargo ramp skin on a model CH-53 helicopter  

NASA Technical Reports Server (NTRS)

The installation of a composite skin panel on the cargo ramp of a CH-530 marine helicopter is discussed. The composite material is of Kevlar/Epoxy (K/E) which replaces aluminum outer skins on the aft two bays of the ramp. The cargo ramp aft region was selected as being a helicopter airframe surface subjected to possible significant field damage and would permit an evaluation of the long term durability of the composite skin panel. A structural analysis was performed and the skin shears determined. Single lap joints of K/E riveted to aluminum were statically tested. The joint tests were used to determine bearing allowables and the required K/E skin gage. The K/E skin panels riveted to aluminum edge members were tested in a shear fixture to confirm the allowable shear and bearing strengths. Impact tests were conducted on aluminum skin panels to determine energy level and damage relationship. The K/E skin panels of various ply orientations and laminate thicknesses were then impacted at similar energy levels. The results of the analysis and tests were used to determine the required K/E skin gages in each of the end two bays of the ramp.

Lowry, D. W.; Rich, M. J.

1983-01-01

85

Stress ratio effect on cyclic debonding in adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

A study was conducted to investigate the stress ratio effect on cyclic debond growth behavior in adhesively bonded composite joints. The system studied consisted of graphite/epoxy adherends bonded with a toughened epoxy adhesive. This study showed that the strain energy release rate range was the driving factor for cyclic debonding of the tested bonded system when subjected to cyclic loads with different stress ratios for both mode I and mixed mode I-II loadings.

Mall, S.; Ramamurthy, G.; Rezaizdeh, M. A.

1987-01-01

86

Stress and failure analysis of mechanically fastened joints in composite laminates  

Microsoft Academic Search

The literature published on single mechanically fastened joints in fiber-reinforced plastics is reviewed. A finite-element model is developed to predict the response of pin-loaded composite plates. The model takes into account contact at the pin–hole interface, progressive damage, large deformation theory, and a non-linear shear stress–strain relationship. To predict the progressive ply failure, the analysis combines Hashin and the maximum

Marie-Laure Dano; Guy Gendron; André Picard

2000-01-01

87

The Effect of Composite Patches on the Failure of Adhesively-Bonded Joints Under Bending Moment  

NASA Astrophysics Data System (ADS)

In this study, it was aimed to compare mechanical behavior of double-strap joints with aluminum (AA2024-T3) or 16-ply laminate of carbon/epoxy composite (T300/934) patches of different orientation angles at their overlap area subjected to bending moment. For this purpose, AA2024-T3 aluminum was used as adherend, while the adhesive was a two-part paste (DP 460). Six different types of joint samples were subjected to bending moment. The effect of patch material on failure load and stress distribution was examined experimentally and numerically. In the numerical analysis, the composite patches were assumed to behave linearly elastic, while adherend and adhesive layers were assumed to be nonlinear. It was found that the data obtained from 3-D finite element analysis were coherent with experimental results. Meanwhile, experiments showed that fiber orientation angles of the patches markedly affected the failure load of joints, failure mode and stress distributions appeared in adhesive and composite.

Akpinar, Salih

2013-12-01

88

Composition of joint fluid in patients undergoing total knee replacement and revision arthroplasty: correlation with flow properties  

Microsoft Academic Search

The protein, phospholipid and hyaluronic acid (HA) contents of joint fluid samples were determined in specimens obtained from patients undergoing total knee arthroplasty (TKA) and revision TKA. It was hypothesized that these components would vary widely among patients undergoing TKA, and that the composition of joint fluid in patients undergoing revision would differ from that in patients undergoing revision. It

Dan Mazzucco; Richard Scott; Myron Spector

2004-01-01

89

Probabilistic and Possibilistic Analyses of the Strength of a Bonded Joint  

NASA Technical Reports Server (NTRS)

The effects of uncertainties on the strength of a single lap shear joint are explained. Probabilistic and possibilistic methods are used to account for uncertainties. Linear and geometrically nonlinear finite element analyses are used in the studies. To evaluate the strength of the joint, fracture in the adhesive and material strength failure in the strap are considered. The study shows that linear analyses yield conservative predictions for failure loads. The possibilistic approach for treating uncertainties appears to be viable for preliminary design, but with several qualifications.

Stroud, W. Jefferson; Krishnamurthy, T.; Smith, Steven A.

2001-01-01

90

Mixed-mode cyclic debonding of adhesively bonded composite joints. M.S. Thesis  

NASA Technical Reports Server (NTRS)

A combined experimental-analytical investigation to characterize the cyclic failure mechanism of a simple composite-to-composite bonded joint is conducted. The cracked lap shear (CLS) specimens of graphite/epoxy adherend bonded with EC-3445 adhesive are tested under combined mode 1 and 2 loading. In all specimens tested, fatigue failure occurs in the form of cyclic debonding. The cyclic debond growth rates are measured. The finite element analysis is employed to compute the mode 1, mode 2, and total strain energy release rates (i.e., GI, GII, and GT). A wide range of mixed-mode loading, i.e., GI/GII ranging from 0.03 to 0.38, is obtained. The total strain energy release rate, G sub T, appeared to be the driving parameter for cyclic debonding in the tested composite bonded system.

Rezaizadeh, M. A.; Mall, S.

1985-01-01

91

Analytical and Numerical Results for an Adhesively Bonded Joint Subjected to Pure Bending  

NASA Technical Reports Server (NTRS)

A one-dimensional, semi-analytical methodology that was previously developed for evaluating adhesively bonded joints composed of anisotropic adherends and adhesives that exhibit inelastic material behavior is further verified in the present paper. A summary of the first-order differential equations and applied joint loading used to determine the adhesive response from the methodology are also presented. The method was previously verified against a variety of single-lap joint configurations from the literature that subjected the joints to cases of axial tension and pure bending. Using the same joint configuration and applied bending load presented in a study by Yang, the finite element analysis software ABAQUS was used to further verify the semi-analytical method. Linear static ABAQUS results are presented for two models, one with a coarse and one with a fine element meshing, that were used to verify convergence of the finite element analyses. Close agreement between the finite element results and the semi-analytical methodology were determined for both the shear and normal stress responses of the adhesive bondline. Thus, the semi-analytical methodology was successfully verified using the ABAQUS finite element software and a single-lap joint configuration subjected to pure bending.

Smeltzer, Stanley S., III; Lundgren, Eric

2006-01-01

92

Influence of interface ply orientation on fatigue damage of adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

An experimental study of cracked-lap-shear specimens was conducted to determine the influence of adherend stacking sequence on debond initiation and damage growth in a composite-to-composite bonded joint. Specimens consisted of quasi-isotropic graphite/epoxy adherends bonded together with either FM-300 or EC 3445 adhesives. The stacking sequence of the adherends was varied such that 0 deg, 45 deg, or 90 deg plies were present at the adherend-adhesive interfaces. Fatigue damage initiated in the adhesive layer in those specimens with 0 deg nd 45 deg interface plies. Damage initiated in the form of ply cracking in the strap adherend for the specimens with 90 deg interface plies. The fatigue-damage growth was in the form of delamination within the composite adherends for specimens with the 90 deg and 45 deg plies next to the adhesive, while debonding in the adhesive resulted for the specimens with 0 deg plies next to the adhesive. Those joints with the 0 deg and 45 deg plies next to either adhesive has essentially the same fatigue-damage-initiation stress levels. These stress levels were 13 and 71 percent higher, respectively, than those for specimens with 90 deg plies next to the EC 3445 and FM-300 adhesives.

Johnson, W. S.; Mall, S.

1985-01-01

93

Influence of interface ply orientation on fatigue damage of adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

An experimental study of cracked-lap-shear specimens was conducted to determine the influence of adherend stacking sequence on debond initiation and damage growth in a composite-to-composite bonded joint. Specimens consisted of quasi-isotropic graphite/epoxy adherends bonded together with either FM-300 or EC 3445 adhesives. The stacking sequence of the adherends was varied such that 0 deg, 45 deg, or 90 deg plies were present at the adherend-adhesive interfaces. Fatigue damage initiated in the adhesive layer in those specimens with 0 deg and 45 deg interface plies. Damaage initiated in the form of ply cracking in the strap adherend for the specimens with 90 deg interface plies. The fatigue-damage growth was in the form of delamination within the composite adherends for specimens with the 90 deg and 45 deg plies next to the adhesive, while debonding in the adhesive resulted for the specimens with 0 deg plies next to the adhesive. Those joints with the 0 deg and 45 deg plies next to either adhesive has essentially the same fatigue-damage-initiation stress levels. These stress levels were 13 and 71 percent higher, respectively, than those for specimens with 90 deg plies next to the EC 3445 and FM-300 adhesives.

Johnson, W. S.; Mall, S.

1986-01-01

94

Effects of hot/wet environments on the fatigue behaviour of composite-to-metal mechanically fastened joints  

SciTech Connect

Because of their high strength-to-weight and stiffness-to-weight ratios, carbon fiber reinforced plastic (CFRP) composite laminates are seeing increasing use, especially in the aerospace industry. In composite-to-metal structures the load transfer between various components is undertaken by the use of mechanically fastened or bonded joints. For example, on the F/A-18 aircraft, numerous composite-to-metal mechanically fastened joints are used to transfer loads from the thick composite wing skin to the metal wing ribs and spars. Previous work, undertaken at ARL, has investigated the fatigue of such joints under ambient conditions. It is widely known that the mechanical properties of CFRP laminates generally degrade considerably under hot/wet environments. A similar degradation is expected for mechanically fastened laminates. The aim of this study was to investigate the effects of hot/wet environments on the fatigue behavior of specific mechanically fastened joints. Results showed a marked decrease in the fatigue life of the composite-to-metal mechanically fastened joints under hot/wet environments when compared to lives attained at ambient and under similar load conditions. The major joint failure mode was failure of the fasteners. Other failure modes were compression failure of the 0{degree} ply layers and delamination growth.

Galea, S.C. [DSTO Aeronautical Research Lab., Fishermens Bend, Victoria (Australia). Airframes and Engines Division; Saunders, D.S. [DSTO Materials Research Lab., Ascot Vale, Victoria (Australia). Ship Structures and Materials Division

1993-12-31

95

Interaction of mixed mode loading on cyclic debonding in adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

A combined experimental and analytical investigation of an adhesively-bonded composite joint was conducted to characterize the fracture mode dependence of cyclic debonding. The system studied consisted of graphite/epoxy adherends bonded with EC 3445 adhesive. Several types of specimens are tested which provide the cyclic debond growth rate measurements under various load conditions: mode 1, mixed mode 1 to 2, and mostly mode 2. This study shows that the total strain-energy-release rate is the governing factor for cyclic debonding.

Mall, S.; Rezaizadeh, M. A.; Ramamurthy, G.

1985-01-01

96

Finite Element Analysis of Composite Joint Configurations with Gaps and Overlaps  

NASA Technical Reports Server (NTRS)

The goal of the current study is to identify scenarios for which thermal and moisture effects become significant in the loading of a composite structure. In the current work, a simple configuration was defined, and material properties were selected. A Fortran routine was created to automate the mesh generation process. The routine was used to create the models for the initial mesh refinement study. A combination of element length and width suitable for further studies was identified. Also, the effect of the overlap length and gap length on computed shear and through-thickness stresses along the bondline of the joints was studied for the mechanical load case. Further, the influence of neighboring gaps and overlaps on these joint stresses was studied and was found to be negligible. The results suggest that for an initial study it is sufficient to focus on one configuration with fixed overlap and gap lengths to study the effects of mechanical, thermal and moisture loading and combinations thereof on computed joint stresses

Krueger, Ronald

2014-01-01

97

Some studies on evaluation of degradation in composite adhesive joints using ultrasonic techniques.  

PubMed

Experimental and theoretical studies on degradation of composite-epoxy adhesive joints were carried out on samples having different interfacial and cohesive properties. Oblique incidence ultrasonic inspection of bonded joints revealed that degradation in the adhesive can be measured by significant variation in reflection amplitude as also by a shift in the minima of reflection spectrum. It was observed that severe degradation of the adhesive leads to failure dominated by interfacial mode. Through this investigation it is demonstrated that a correlation exists between the bond strength and a frequency shift in reflection minimum. The experimental data was validated using analytical models. Though both bulk adhesive degradation and interfacial degradation influences the shift in spectrum minimum, the contribution of the latter was found to be significant. An inversion algorithm was used to determine the interfacial transverse stiffness using the experimental oblique reflection spectrum. The spectrum shift was found to depend on the value of interfacial transverse stiffness using which a qualitative assessment can be made on the integrity of the joint. PMID:23541960

Vijaya Kumar, R L; Bhat, M R; Murthy, C R L

2013-08-01

98

SiC nanowires reinforced MAS joint of SiC coated carbon\\/carbon composites to LAS glass ceramics  

Microsoft Academic Search

In order to improve the shear strength of the joints of carbon\\/carbon (C\\/C) composites to lithium aluminum silicate (LAS) glass ceramics, SiC coating and magnesium aluminum silicate (MAS) glass ceramics were used as transition layer and middle layer, respectively, and high quality SiC nanowires were applied as the reinforcement materials in MAS. The SiC nanowires reinforced MAS joint of SiC

Qiangang Fu; Binglin Jia; Hejun Li; Kezhi Li Yanhui Chu

99

Test results for composite specimens and elements containing joints and cutouts  

NASA Technical Reports Server (NTRS)

A program was conducted to develop the technology for joints and cutouts in a composite fuselage that meets all design requirements of a large transport aircraft for the 1990s. An advanced trijet derivative of the DC-10 was selected as the baseline aircraft. Design and analysis of a 30-foot-long composite fuselage barrel provided a realistic basis for the test effort. The primary composite material was Hexcel F584 resin on 12 K IM6 fiber, in tape and broadgoods form. Fiberglass broadgoods were used in E-glass and S-glass fiber form in the cutout region of some panels. Additionally, injection-molded chopped graphite fiber/PEEK was used for longeron-to-frame shear clips. The test effort included four groups of test specimens, beginning with coupon specimens of mono-layer and cross-piled laminates, progressing through increasingly larger and more complex specimens, and ending with two 4- by 5-foot curved fuselage side panels. One of the side panels incorporated a transverse skin splice, while the second included two cabin window cutouts.

Sumida, P. T.; Madan, R. C.; Hawley, A. V.

1988-01-01

100

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

NASA Astrophysics Data System (ADS)

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.

P?ltânea, Veronica; P?ltânea, Gheorghe; Popovici, Dorina; Jiga, Gabriel; Papanicolaou, George

2014-05-01

101

Numerical and experimental stress analysis of a polymeric composite hip joint prosthesis.  

PubMed

A comparative stress analysis of a polymeric composite hip joint replacement was performed. A prototype short carbon-fiber reinforced PEEK (CF/PEEK) prosthesis was manufactured by injection molding. Finite element (FE) analysis was conducted on intact femurs and femurs fitted with the CF/ PEEK and the titanium prostheses under various loading conditions. FE models were validated by experimental strain gauge measurements by using synthetic femurs. There was a good agreement between the two methods except in the hoop strain of the femur in the calcar region because of the assumption of the isotropic material properties. The stem stresses were lower for the CF/PEEK prosthesis than for the titanium prosthesis. The maximum stress was in the spigot of the CF/PEEK prosthesis, but in the middle third of the stem of the titanium prosthesis. Stress generated in the cement was almost equal for both prostheses although more load was transferred, via cement, to the femur with the CF/ PEEK prosthesis because the load transfer took place over a larger area. An out-of-plane component of the joint load causes higher prosthesis and cement stresses. PMID:8731205

Akay, M; Aslan, N

1996-06-01

102

Design aid for shear strengthening of reinforced concrete T-joints using carbon fiber reinforced plastic composites  

NASA Astrophysics Data System (ADS)

The research presented in the present work focuses on the shear strengthening of beam column joints using carbon fiber composites, a material considered in seismic retrofit in recent years more than any other new material. These composites, or fiber reinforced polymers, offer huge advantages over structural steel reinforced concrete or timber. A few of these advantages are the superior resistance to corrosion, high stiffness to weight and strength to weight ratios, and the ability to control the material's behavior by selecting the orientation of the fibers. The design and field application research on reinforced concrete cap beam-column joints includes analytical investigations using pushover analysis; design of carbon fiber layout, experimental tests and field applications. Several beam column joints have been tested recently with design variables as the type of composite system, fiber orientation and the width of carbon fiber sheets. The surface preparation has been found to be critical for the bond between concrete and composite material, which is the most important factor in joint shear strengthening. The final goal of this thesis is to develop design aids for retrofitting reinforced concrete beam column joints. Two bridge bents were tested on the Interstate-15 corridor. One bent was tested in the as-is condition. Carbon fiber reinforced plastic composite sheets were used to externally reinforce the second bridge bent. By applying the composite, the displacement ductility has been doubled, and the bent overall lateral load capacity has been increased as well. The finite element model (using DRAIN-2DX) was calibrated to model the actual stiffness of the supports. The results were similar to the experimental findings.

Gergely, Ioan

103

Analysing Group Creativity: A Distributed Cognitive Study of Joint Music Composition Shahin Nabavian (shahin@dcs.qmul.ac.uk)  

E-print Network

Analysing Group Creativity: A Distributed Cognitive Study of Joint Music Composition Shahin in an instance of group creativity by conducting a pilot study that looked closely at a group of expert musicians identified three key processes (attainment, experimentation and structuring) that help the group achieve

Bryan-Kinns, Nick

104

Flaw Tolerance in Lap Shear Brazed Joints. Part 1  

NASA Technical Reports Server (NTRS)

Vacuum brazing is a viable process to achieve strong permanent and hermetic joints in space. As in any joining process, brazed Joints have various imperfections and defects. It is important to understand the impact that flaws have on the load carrying capacity and performance of the brazed joints. This study focuses on the behavior of lap shear joints due to their engineering importance in brazed aerospace structures. In Part 1 an average shear strength capabilitY and failure modes of the single lap joints are explored. Specimens comprised of 0.090 inch thick 347 stainless steel sheet brazed with pure silver are tested in accordance with the AWS C3.2 standard. Comparison of the measured loads and average shear stresses at failure with the Finite Element Analysis (FEA) of the same specimens as a function of the overlap lengths shows excellent correlation between the experimental and calculated values for the defect-free lap joints. In Part 2, various flaws will be introduced in the test specimens to simulate lack of braze coverage in the lap joints. Mechanical testing and FEA will be performed on these joints to verify if behavior of ductile ]appoints containing flaws is similar to the joints with the reduced braze area. Finally, in Part 3, the results obtained in Part 1 and 2 will be applied to the brazed assembly to evaluate a load carrying capability of the structural lap joint containing defects.

Flom, Yury; Wang, Liqin; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

105

Analysis of a Preloaded Bolted Joint in a Ceramic Composite Combustor  

NASA Technical Reports Server (NTRS)

This paper presents the detailed analysis of a preloaded bolted joint incorporating ceramic materials. The objective of this analysis is to determine the suitability of a joint design for a ceramic combustor. The analysis addresses critical factors in bolted joint design including preload, preload uncertainty, and load factor. The relationship between key joint variables is also investigated. The analysis is based on four key design criteria, each addressing an anticipated failure mode. The criteria are defined in terms of margin of safety, which must be greater than zero for the design criteria to be satisfied. Since the proposed joint has positive margins of safety, the design criteria are satisfied. Therefore, the joint design is acceptable.

Hissam, D. Andy; Bower, Mark V.

2003-01-01

106

Design, fabrication and test of graphite/polyimide composite joints and attachments for advanced aerospace vehicles  

NASA Technical Reports Server (NTRS)

The design and evaluation of built-up attachments and bonded joint concepts for use at elevated temperatures is documented. Joint concept screening, verification of GR/PI material, fabrication of design allowables panels, definition of test matrices, and analysis of bonded and bolted joints are among the tasks completed. The results provide data for the design and fabrication of lightly loaded components for advanced space transportation systems and high speed aircraft.

Koumal, D. E.

1979-01-01

107

21 CFR 26.17 - Role and composition of the Joint Sectoral Committee.  

Code of Federal Regulations, 2013 CFR

...of inspecting type or products, and communicating the list to all authorities and the Joint Committee; (3) Providing a forum to discuss issues relating to this subpart, including concerns that an authority may be no longer equivalent and...

2013-04-01

108

Multifunctional composite coating as a wear-resistant layer for the bearing in total hip joint replacement.  

PubMed

In this study, we developed Ti-TiN composite coatings with fine lamellar structures for use as an enhanced wear-resistant layer between the bearing components of the polymer-lined acetabular cup and the metal femoral head of total hip joint replacements (THRs). A plasma spraying deposition method was used to apply the composite coatings, and the thickness of TiN layer in the composite could be controlled by varying the flow rate of N(2) atmospheric gas. The surface properties, such as roughness and hardness, were analyzed, and the friction coefficient (?) and wear rate (k) were measured using a bovine serum wear test. A biocompatibility test was performed to evaluate the toxicity of the composite coatings. Our experimental results reveal that the friction and wear resistance of composite coatings is superior to that of the metallic implant materials, and they have a higher level of fracture toughness as compared with other ceramic coatings because of a good balance between the hardness of the TiN and the toughness of the Ti. Furthermore, these coatings possessed excellent biocompatibility. The experimental results also demonstrate that the improved wear properties can be attributed to a certain level of unavoidable porosity that is due to the rapid solidification of liquid droplets during the plasma spraying process. The pores in the coating surface play an important role as a lubricant (bovine serum) reservoir, reducing the actual contact area and friction losses. PMID:23249257

Cho, Seung Mok; Park, Jin-Woo; Han, Hyung-Seop; Seok, Hyun-Kwang; Moon, Myoung-Woon; Kim, Yu Chan

2013-01-23

109

Active Metal Brazing and Characterization of Brazed Joints in C-C and C-SiC Composites to Copper-Clad-Molybdenum System  

NASA Technical Reports Server (NTRS)

Carbon/carbon composites with CVI and resin-derived matrices, and C/SiC composites reinforced with T-300 carbon fibers in a CVI SiC matrix were joined to Cu-clad Mo using two Ag-Cu braze alloys, Cusil-ABA (1.75% Ti) and Ticusil (4.5% Ti). The brazed joints revealed good interfacial bonding, preferential precipitation of Ti at the composite/braze interface, and a tendency toward delamination in resin-derived C/C composite. Extensive braze penetration of the inter-fiber channels in the CVI C/C composites was observed. The Knoop microhardness (HK) distribution across the C/C joints indicated sharp gradients at the interface, and a higher hardness in Ticusil than in Cusil-ABA. For the C/SiC composite to Cu-clad-Mo joints, the effect of composite surface preparation revealed that ground samples did not crack whereas unground samples cracked. Calculated strain energy in brazed joints in both systems is comparable to the strain energy in a number of other ceramic/metal systems. Theoretical predictions of the effective thermal resistance suggest that such joined systems may be promising for thermal management applications.

Singh, M.; Asthana, R.

2008-01-01

110

Impact-fatigue behavior of composite tube\\/metal end fitting bonded joints  

Microsoft Academic Search

The relatively high specific strengths and moduli of advanced composite materials make them an attractive option for use in high speed industrial equipment. Hence, a potential market exists for integrating composites into existing machinery to replace critical metallic components. An application of such is the replacement of a high speed reciprocating steel bodymaker ram with one fabricated from a filament

B. W. Barber; D. W. Radford

1995-01-01

111

High density polyethylene/graphite nano-composites for total hip joint replacements: processing and in vitro characterization.  

PubMed

The main objective of the present study is to investigate how the thermal, rheological, mechanical and cytotoxicity behavior of High Density Polyethylene (HDPE) can be changed by the addition of graphite nano particles (GNPs) at different contents. The HDPE/GNPs composites were prepared using melt blending in a co-rotating intermeshing twin screw extruder. The in vitro tests results showed that the original material (HDPE) and all HDPE/GNPs composites do not exhibit any cytotoxicity to the WISH cell line. The microscopic examination of the nano-composite tensile-fractured surface found a good distribution of GNPs in the HDPE matrix. The Differential Scanning Calorimetry (DSC) results indicated that the crystallization percentage increased by adding GNPs to HDPE up to 4%. The XRD patterns of the HDPE/GNPs composites showed an increase in peak intensity compared to neat HDPE. This increase echoed the crystallinity results obtained from DSC. The rheological tests showed that the complex viscosity of the HDPE increased as the percentage of GNPs increased due to the restriction of the molecular mobility. The tensile test results showed that with increasing the GNPs content, Young's modulus and the yield strength of the HDPE/GNPs composite increased while the strain at fracture decreased. Finally, the preliminary results of the abrasion test indicated that the abrasion rate decreased by increasing the GNPs ratio up to 4% content. The prepared HDPE/GNPs composites appear to have fairly good comprehensive properties that make them a good candidate as a bearing material for the total joint replacement. PMID:21783148

Fouad, H; Elleithy, Rabeh

2011-10-01

112

Combined In-Plane and Through-the-Thickness Analysis for Failure Prediction of Bolted Composite Joints  

NASA Technical Reports Server (NTRS)

Although two-dimensional methods provide accurate predictions of contact stresses and bolt load distribution in bolted composite joints with multiple bolts, they fail to capture the effect of thickness on the strength prediction. Typically, the plies close to the interface of laminates are expected to be the most highly loaded, due to bolt deformation, and they are usually the first to fail. This study presents an analysis method to account for the variation of stresses in the thickness direction by augmenting a two-dimensional analysis with a one-dimensional through the thickness analysis. The two-dimensional in-plane solution method based on the combined complex potential and variational formulation satisfies the equilibrium equations exactly, and satisfies the boundary conditions and constraints by minimizing the total potential. Under general loading conditions, this method addresses multiple bolt configurations without requiring symmetry conditions while accounting for the contact phenomenon and the interaction among the bolts explicitly. The through-the-thickness analysis is based on the model utilizing a beam on an elastic foundation. The bolt, represented as a short beam while accounting for bending and shear deformations, rests on springs, where the spring coefficients represent the resistance of the composite laminate to bolt deformation. The combined in-plane and through-the-thickness analysis produces the bolt/hole displacement in the thickness direction, as well as the stress state in each ply. The initial ply failure predicted by applying the average stress criterion is followed by a simple progressive failure. Application of the model is demonstrated by considering single- and double-lap joints of metal plates bolted to composite laminates.

Kradinov, V.; Madenci, E.; Ambur, D. R.

2004-01-01

113

21 CFR 888.3100 - Ankle joint metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...cobalt-chromium-molybdenum, and a tibial resurfacing component fabricated from ultra-high molecular weight polyethylene with carbon fibers composite, and is limited to those prostheses intended for use with bone cement (§ 888.3027). (b)...

2010-04-01

114

21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...cobalt-chromium-molybdenum, and an acetabular component made of ultra-high molecular weight polyethylene with carbon fibers composite. Both components are intended for use with bone cement (§ 888.3027). (b) Classification....

2010-04-01

115

21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...cobalt-chromium-molybdenum, and a tibial condylar component or components made of ultra-high molecular weight polyethylene with carbon fibers composite and are intended for use with bone cement (§ 888.3027). (b) Classification. Class...

2010-04-01

116

21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2012 CFR

...generic type of device includes prostheses that consist of a femoral component made of alloys, such as cobalt-chromium-molybdenum, and an acetabular component made of ultra-high molecular weight polyethylene with carbon fibers composite. Both...

2012-04-01

117

21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.  

...generic type of device includes prostheses that consist of a femoral component made of alloys, such as cobalt-chromium-molybdenum, and an acetabular component made of ultra-high molecular weight polyethylene with carbon fibers composite. Both...

2014-04-01

118

21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2013 CFR

...generic type of device includes prostheses that consist of a femoral component made of alloys, such as cobalt-chromium-molybdenum, and an acetabular component made of ultra-high molecular weight polyethylene with carbon fibers composite. Both...

2013-04-01

119

Construction of tissue-engineered osteochondral composites and repair of large joint defects in rabbit.  

PubMed

In this study, a novel three-dimensional (3D) heterogeneous/bilayered scaffold was constructed to repair large defects in rabbit joints. The scaffold includes two distinct but integrated layers corresponding to the cartilage and bone components. The upper layer consists of gelatin, chondroitin sulphate and sodium hyaluronate (GCH), and the lower layer consists of gelatin and ceramic bovine bone (GCBB). The two form a 3D bilayered scaffold (GCH-GCBB), which mimics the natural osteochondral matrix for use as a scaffold for osteochondral tissue engineering. The purpose of this study was to evaluate the efficacy of this novel scaffold, combined with chondrocytes and bone marrow stem cells (BMSCs) to repair large defects in rabbit joints. Thirty-six large defects in rabbit femoral condyles were created; 12 defects were treated with the same scaffold combined with cells (group A); another 12 defects were treated with cell-free scaffolds (group B); the others were untreated (group C). At 6 and 12?weeks, in group A hyaline-like cartilage formation could be observed by histological examination; the newly formed cartilage, which stained for type II collagen, was detected by RT-PCR at high-level expression. Most of the GCBB was replaced by bone, while little remained in the underlying cartilage. At 36?weeks, GCBB was completely resorbed and a tidemark was observed in some areas. In contrast, groups B and C showed no cartilage formation but a great amount of fibrous tissue, with only a little bone formation. In summary, this study demonstrated that a novel scaffold, comprising a top layer of GCH, having mechanical properties comparable to native cartilage, and a bottom layer composed of GCBB, could be used to repair large osteochondral defects in joints. PMID:22777833

Deng, Tianzheng; Lv, Jing; Pang, Jianliang; Liu, Bing; Ke, Jie

2014-07-01

120

Evolution equations for the joint probability of several compositions in turbulent combustion  

SciTech Connect

One-point statistical simulations of turbulent combustion require models to represent the molecular mixing of species mass fractions, which then determine the reaction rates. For multi-species mixing the Dirichlet distribution has been used to characterize the assumed joint probability density function (PDF) of several scalars, parametrized by solving modeled evolution equations for their means and the sum of their variances. The PDF is then used to represent the mixing state and to obtain the chemical reactions source terms in moment closures or large eddy simulation. We extend the Dirichlet PDF approach to transported PDF methods by developing its governing stochastic differential equation (SDE). The transport equation, as opposed to parametrizing the assumed PDF, enables (1) the direct numerical computation of the joint PDF (and therefore the mixing model to directly account for the flow dynamics (e.g. reaction) on the shape of the evolving PDF), and (2) the individual specification of the mixing timescales of each species. From the SDE, systems of equations are derived that govern the first two moments, based on which constraints are established that provide consistency conditions for material mixing. A SDE whose solution is the generalized Dirichlet PDF is also developed and some of its properties from the viewpoint of material mixing are investigated. The generalized Dirichlet distribution has the following advantages over the standard Dirichlet distribution due to its more general covariance structure: (1) its ability to represent differential diffusion (i.e. skewness) without affecting the scalar means, and (2) it can represent both negatively and positively correlated scalars. The resulting development is a useful representation of the joint PDF of inert or reactive scalars in turbulent flows: (1) In moment closures, the mixing physics can be consistently represented by one underlying modeling principle, the Dirichlet or the generalized Dirichlet PDF, and (2) based on the SDEs transported PDF mixing models for multi-species diffusion can be constructed by specifying the SDE coefficients.

Bakosi, Jozsef [Los Alamos National Laboratory

2010-01-01

121

Extracellular matrix stiffness and composition jointly regulate the induction of malignant phenotypes in mammary epithelium  

NASA Astrophysics Data System (ADS)

In vitro models of normal mammary epithelium have correlated increased extracellular matrix (ECM) stiffness with malignant phenotypes. However, the role of increased stiffness in this transformation remains unclear because of difficulties in controlling ECM stiffness, composition and architecture independently. Here we demonstrate that interpenetrating networks of reconstituted basement membrane matrix and alginate can be used to modulate ECM stiffness independently of composition and architecture. We find that, in normal mammary epithelial cells, increasing ECM stiffness alone induces malignant phenotypes but that the effect is completely abrogated when accompanied by an increase in basement-membrane ligands. We also find that the combination of stiffness and composition is sensed through ?4 integrin, Rac1, and the PI3K pathway, and suggest a mechanism in which an increase in ECM stiffness, without an increase in basement membrane ligands, prevents normal ?6?4 integrin clustering into hemidesmosomes.

Chaudhuri, Ovijit; Koshy, Sandeep T.; Branco da Cunha, Cristiana; Shin, Jae-Won; Verbeke, Catia S.; Allison, Kimberly H.; Mooney, David J.

2014-10-01

122

Structural health monitoring of composite T-joints for assessing the integrity of damage zones  

NASA Astrophysics Data System (ADS)

This paper uses one category of Structural Health Monitoring (SHM) which uses strain variation across a structure as the key to damage detection. The structure used in this study was made from Glass Fibre Reinforced Plastic (GFRP). This paper discusses a technique developed called "Global Neural network Architecture Incorporating Sequential Processing of Internal sub Networks (GNAISPIN)" to predict the presence of multiple damage zones, determine their positions and also predict the extent of damage. Finite Element (FE) models of T-joints, used in ship structures, were created using MSC Patran (R) . These FE models were created with delaminations embedded at various locations across the bond-line of the structure. The resulting strain variation across the surface of the structure was observed. The validity of the Finite Element model was then verified experimentally. GNAISPIN was then used in tandem with the Damage Relativity Analysis Technique to predict and estimate the presence of multiple delaminations.

Kesavan, A.; Deivasigamani, M.; John, S.; Herszberg, I.

2006-03-01

123

GUIDED WAVE PROPAGATION THROUGH COMPOSITE BONDED JOINTS Mohammad H. Sherafat1  

E-print Network

guided wave propagation technique. Two carbon fiber reinforced polymer (CFRP) are bonded together using corrosion and fatigue damage better than traditional aluminum alloys. Despite enhancements in terms of concern. These types of damage in composite structures can significantly jeopardize their performance

Paris-Sud XI, Université de

124

21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...cobalt-chromium-molybdenum, and a tibial component with the articulating surfaces made of ultra-high molecular weight polyethylene with carbon-fibers composite and is limited to those prostheses intended for use with bone cement (§ 888.3027). (b)...

2010-04-01

125

Optimal design of the press fit joint for a hybrid aluminum\\/composite drive shaft  

Microsoft Academic Search

In this work, a one-piece hybrid drive shaft composed of aluminum and carbon\\/epoxy composite was designed for a rear wheel drive automobile. The aluminum yoke was joined to the hybrid shaft by the press fit joining method using a steel ring which has many small teeth to increase reliability and to reduce manufacturing cost. To obtain high strength of the

Hak Sung Kim; Dai Gil Lee

2005-01-01

126

Synovial fluid lubrication of artificial joints: protein film formation and composition.  

PubMed

Despite design improvements, wear of artificial implants remains a serious health issue particularly for Metal-on-Metal (MoM) hips where the formation of metallic wear debris has been linked to adverse tissue response. Clearly it is important to understand the fundamental lubrication mechanisms which control the wear process. It is usually assumed that MoM hips operate in the ElastoHydrodynamic Lubrication (EHL) regime where film formation is governed by the bulk fluid viscosity; however there is little experimental evidence of this. The current paper critically examines synovial fluid lubrication mechanisms and the effect of synovial fluid chemistry. Two composition parameters were chosen; protein content and pH, both of which are known to change in diseased or post-operative synovial fluid. Film thickness and wear tests were carried out for a series of model synovial fluid solutions. Two distinct film formation mechanisms were identified; an adsorbed surface film and a high-viscosity gel. The entrainment of this gel controls film formation particularly at low speeds. However wear of the femoral head still occurs and this is thought to be due primarily to a tribo-corrosion mechanisms. The implications of this new lubrication mechanism and the effect of different synovial fluid chemistries are examined. One important conclusion is that patient synovial fluid chemistry plays an important role in determining implant wear and the likelihood of failure. PMID:23285623

Fan, Jingyun; Myant, Connor; Underwood, Richard; Cann, Philippa

2012-01-01

127

Effect of adherend thickness and mixed mode loading on debond growth in adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

Symmetric and unsymmetric double cantilever beam (DCB) specimens were tested and analyzed to assess the effect of: (1) adherend thickness, and (2) a predominantly mode I mixed mode loading on cyclic debond growth and static fracture toughness. The specimens were made of unidirectional composite (T300/5208) adherends bonded together with EC3445 structural adhesive. The thickness was 8, 16, or 24 plies. The experimental results indicated that the static fracture toughness increases and the cyclic debond growth rate decreases with increasing adherend thickness. This behavior was related to the length of the plastic zone ahead of the debond tip. For the symmetric DCB specimens, it was further found that displacement control tests resulted in higher debond growth rates than did load control tests. While the symmetric DCB tests always resulted in cohesive failures in the bondline, the unsymmetric DCB tests resulted in the debond growing into the thinner adherend and the damage progressing as delamination in that adherend. This behavior resulted in much lower fracture toughness and damage growth rates than found in the symmetric DCB tests.

Mangalgiri, P. D.; Johnson, W. S.; Everett, R. A., Jr.

1986-01-01

128

Microstructure and Phase Composition of a Low-Power YAG Laser-MAG Welded Stainless Steel Joint  

NASA Astrophysics Data System (ADS)

This article presents multipass hybrid welding of austenitic stainless steel (ASS) structure by using the low-power Nd:YAG laser-metal active gas (MAG) arc hybrid welding method. The purpose of this work is to investigate and qualify the effects of multipass hybrid welding of ASS structure on the microstructure, phase composition, weld postheat influence, and weld bead (WB) precipitated phase. The results demonstrated that sound welded joints without any solidification and shrinkage defects could be obtained after welding. The top and the bottom portions of the workpieces were joined completely. At room temperature, the microstructures of different regions in WB were different and the WB microstructures were composed of columnar ?-austenite and ?-ferrite phases. The fraction of ?-ferrite decreased from 20% to 10%, and its morphology changed orderly from lath, skeleton, vermicular to reticular with an increase in the number of welding cycles. Because of the influence of postweld heat, the weld metal phase chemistry at 3 mm distance from the top of the WB surface underwent a notable modification that corresponded to an evolution of the partition coefficients toward the parent metal values. This indicated corrosion resistance of the microstructure is equivalent to that of the parent metal.

Huang, R. S.; Kang, L.; Ma, X.

2008-12-01

129

Effect of Filler Metal Composition on the Strength of Yttria Stabilized Zirconia Joints Brazed with Pd-Ag-CuO x  

NASA Astrophysics Data System (ADS)

Various compositions in the Ag-CuO x system are being investigated as potential filler metals for use in air brazing high-temperature electrochemical devices such as solid oxide fuel cells and gas concentrators. Prior work has shown that the melting temperature, and therefore the potential operational temperature, of these materials can be increased by alloying with palladium. The current study examines the effects of palladium addition on the joint strength of specimens prepared from yttria stabilized zirconia (YSZ) bars brazed with three different families of filler metals: Ag-CuO, 5Pd-Ag-CuO, and 15Pd-Ag-CuO. In general, it was found that palladium leads to a small-to-moderate decrease in joint strength, particularly in low copper oxide containing filler metals. However, the declination in strength is likely an acceptable trade-off for increased use temperature. In addition, a critical composition was observed for each filler metal series at which the mechanism for joint failure underwent a transition, typically from ductile to brittle failure. In each case, this composition corresponds approximately to the silver-rich boundary composition of the liquid miscibility gap in each system at the temperature of brazing.

Darsell, Jens T.; Weil, K. Scott

2008-09-01

130

Study on the anti-wear performance of Ni-base composite coating sucker joint that contains nano-diamond and nano-polytetrafluoroethylene.  

PubMed

With the development of oilfields, the problem of eccentric wear between casing and sucker rod in rod-pumped wells operation is more and more severe. Investigations on the eccentric wear show that the abrasion of sucker rod joint is more serious than the sucker rod itself. A new method of producing the Ni-base composite coating that contains nano-diamond and nano-polytetrafluoroethylene (PTFE) on sucker joint obtained by electrodeposition is presented in this paper. The test results show that the anti-wear performance and hardness of the sucker rod improve significantly with the increase of nano-diamond. The addition of nano-PTFE particle is useful in reducing the friction factor. Field tests demonstrate that the life of the sucker rod joint is increased and the maintenance cycle of the rod-pumped well is prolonged. PMID:19441509

Wang, Wei-Zhang; Yan, Xiang-Zhen; Wang, Hai-Wen; Wang, Ming-Bo

2009-02-01

131

A novel approach to predict the pin load distribution of multiple bolt-jointed composite laminate based on the circuit model  

NASA Astrophysics Data System (ADS)

The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.

Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao

2011-11-01

132

A novel approach to predict the pin load distribution of multiple bolt-jointed composite laminate based on the circuit model  

NASA Astrophysics Data System (ADS)

The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.

Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao

2012-04-01

133

Effect of current crowding and Joule heating on electromigration-induced failure in flip chip composite solder joints tested at room temperature  

SciTech Connect

The electromigration of flip chip solder joints consisting of 97Pb-3Sn and 37Pb-63Sn composite solders was studied under high current densities at room temperature. The mean time to failure and failure modes were found to be strongly dependent on the change in current density. The composite solder joints did not fail after 1 month stressed at 4.07x10{sup 4} A/cm{sup 2}, but failed after just 10 h of current stressing at 4.58x10{sup 4} A/cm{sup 2}. At a slightly higher current stressing of 5.00x10{sup 4} A/cm{sup 2}, the composite solder joints failed after only 0.6 h due to melting. Precipitation and growth of Cu{sub 6}Sn{sub 5} at the cathode caused the Cu under bump metallurgy to be quickly consumed and resulted in void formation at the contact area. The void reduced the contact area and displaced the electrical path, affecting the current crowding and Joule heating inside the solder bump. Significant Joule heating inside solder bumps can cause melting of the solder and quick failure. The effect of void propagation on current crowding and Joule heating was confirmed by simulation.

Nah, J.W.; Suh, J.O.; Tu, K.N. [Department of Materials Science and Engineering, University of California at Los Angeles (UCLA), Los Angeles, California 90095-1595 (United States)

2005-07-01

134

Electro-optically responsive composites of gold nanospheres in 5CB liquid crystal under direct current and alternating current joint action  

NASA Astrophysics Data System (ADS)

Direct current (DC) electro-optical (EO) control of transmitted laser beam intensity based on EO controlled coherent light scattering and diffraction by stationary longitudinal texture pattern (LTP) is achieved in planar-oriented cells with a composite mixture of polymer-coated gold spherical nanoparticles (Au-NPs) with a mean diameter of about 12 nm and the room-temperature nematic pentylcyanobiphenyl (5CB). At relatively low DC voltage of about 5 V, the effective scattering/diffraction by Au-NPs/5CB composites leads to a spatial spreading of transmitted coherent light from a low-power continuous wave laser beam, resulting in a drastic reduction of its local intensity. The effect is polarization dependent and is strongest when the polarization of the input laser beam is along the LTP. The EO response of Au-NPs/5CB mixtures is studied under DC and alternating current (AC) joint action with the aim of the potential use of these composite materials as EO controlled diffusers. The specific V-shaped sharp dip in the DC voltage-dependent coherent light transmittance of Au-NPs/5CB planar films, as well as the possibility for erasing the scattering/diffractive LTP in the films by joint low AC voltage, can be useful for EO applications in the field of process control and for detection of weak dynamic electric fields.

Hadjichristov, Georgi B.; Marinov, Yordan G.; Petrov, Alexander G.; Bruno, Emanuela; Marino, Lucia; Scaramuzza, Nicola

2014-02-01

135

In situ compressive stiffness, biochemical composition, and structural integrity of articular cartilage of the human knee joint  

Microsoft Academic Search

Objective Reduction of compressive stiffness of articular cartilage has been reported as one of the first signs of cartilage degeneration. For the measurement of in situ compressive stiffness, a hand-held indentation probe has recently been developed and baseline data for macroscopically normal knee joint cartilage were provided. However, the histological stage of degeneration of the measured cartilage was not known.

T. Franz; E. M. Hasler; R. Hagg; C. Weiler; R. P. Jakob; P. Mainil-Varlet

2001-01-01

136

Influence of aluminum, silicon, and copper on the properties of composite welded joints in an iron base  

Microsoft Academic Search

The properties of welded steel-aluminum joints is governed to a considerable extent by the type of plating preliminarily applied to the steel and the dimensions and character of the diffusion layer produced at the boundary between the iron and molten aluminum [1]. The present investigation completed our study of the influence of alloying Of the iron base on the properties

V. R. Ryabov; V. I. Yumatova

1975-01-01

137

Environmental Aging of Scotch-Weld(TradeMark) AF-555M Structural Adhesive in Composite to Composite Bonds  

NASA Technical Reports Server (NTRS)

Fiber reinforced resin matrix composites have found increased usage in recent years. Due to the lack of service history of these relatively new material systems, their long-term aging performance is not well established. In this study, adhesive bonds were prepared by the secondary bonding of Scotch-Weld(TradeMark) AF-555M between pre-cured adherends comprised of T800H/3900-2 uni-directional laminate. The adherends were co-cured with wet peel-ply for surface preparation. Each bond-line of single-lap-shear (SLS) specimen was measured to determine thickness and inspected visually for voids. A three-year environmental aging plan for the SLS specimens at 82 C and 85% relative humidity was initiated. SLS strengths were measured for both controls and aged specimens at room temperature and 82 C. The aging results of strength retention and failure modes to date are reported.

Hou, Tan-Hung; Miner, Gilda A.; Lowther, Sharon E.; Connell, John W.; Baughman, James M.

2010-01-01

138

Probabilistic and Possibilistic Analyses of the Strength of a Bonded Joint  

NASA Technical Reports Server (NTRS)

The effects of uncertainties on the predicted strength of a single lap shear joint are examined. Probabilistic and possibilistic methods are used to account for uncertainties. A total of ten variables are assumed to be random, with normal distributions. Both Monte Carlo Simulation and the First Order Reliability Method are used to determine the probability of failure. Triangular membership functions with upper and lower bounds located at plus or minus three standard deviations are used to model uncertainty in the possibilistic analysis. The alpha cut (or vertex) method is used to evaluate the possibility of failure. Linear and geometrically nonlinear finite element analyses are used calculate the response of the joint; fracture in the adhesive and material strength failure in the strap are used to evaluate its strength. Although probabilistic and possibilistic analyses provide significantly more information than do conventional deterministic analyses, they are computationally expensive. A novel scaling approach is developed and used to substantially reduce the computational cost of the probabilistic and possibilistic analyses. The possibilistic approach for treating uncertainties appears to be viable during the conceptual and preliminary design stages when limited data are available and high accuracies are not needed. However, this viability is mixed with several cautions that are discussed herein.

Stroud, W. Jefferson; Krishnamurthy, T.; Smith, Steven A.

2002-01-01

139

Analysis of bonded joints. [shear stress and stress-strain diagrams  

NASA Technical Reports Server (NTRS)

A refined elastic analysis of bonded joints which accounts for transverse shear deformation and transverse normal stress was developed to obtain the stresses and displacements in the adherends and in the bond. The displacements were expanded in terms of polynomials in the thicknesswise coordinate; the coefficients of these polynomials were functions of the axial coordinate. The stress distribution was obtained in terms of these coefficients by using strain-displacement and stress-strain relations. The governing differential equations were obtained by integrating the equations of equilibrium, and were solved. The boundary conditions (interface or support) were satisfied to complete the analysis. Single-lap, flush, and double-lap joints were analyzed, along with the effects of adhesive properties, plate thicknesses, material properties, and plate taper on maximum peel and shear stresses in the bond. The results obtained by using the thin-beam analysis available in the literature were compared with the results obtained by using the refined analysis. In general, thin-beam analysis yielded reasonably accurate results, but in certain cases the errors were high. Numerical investigations showed that the maximum peel and shear stresses in the bond can be reduced by (1) using a combination of flexible and stiff bonds, (2) using stiffer lap plates, and (3) tapering the plates.

Srinivas, S.

1975-01-01

140

Pin-on-disc evaluation of self-reinforced composite poly(methyl methacrylate) for total joint replacements.  

PubMed

Femoral components of hip replacements are commonly anchored in the femur with bone cement or poly(methyl methacrylate) (PMMA). Wear or fracture of bone cement can lead to loosening of the femoral component, which drastically affects the success and longevity of hip replacements. Self-reinforced composite PMMA (SRC-PMMA) has been previously developed for potential use, as a precoat material for hip replacements. The composite consists of high strength fibers that have been shown to have greatly improved mechanical properties over bulk PMMA. The goal of this work was to examine SRC-PMMA for improved wear properties, as a function of processing temperature. Pin-on-disc tests were used to characterize and rank the wear rates of SRC-PMMA and PMMA. Composites made with higher processing temperatures had significantly lower wear rates than do PMMA at a significance level of p < or = 0.05. The lowest wear rate was 8.2 microg/m, at a processing temperature of 136 degrees C, compared to a wear rate for PMMA of 13.3 microg/m. At the lowest processing temperature (105 degrees C), a wear rate higher than PMMA was found, and failure was dominated by fiber delamination. In the more completely processed samples (122 degrees C < or = T < or = 150 degrees C), wear rates were equivalent to or better than PMMA, and smoother and more homogenous wear was noted in wear tracks. Fatigue cracks were prominent at higher processing temperatures or when the wear pin was riding orthogonal to fibers. Wear particles were collected and examined. Wear particle diameter and aspect ratio showed no correlation to processing temperature, but were similar to particles retrieved from human tissue samples. PMID:16544304

Peers, William J; Wright-Charlesworth, Debra D; Miskioglu, Ibrahim

2006-10-01

141

Evolving flexible joint morphologies  

Microsoft Academic Search

Transferring virtual robotic designs into physical robots has become possible with the development of 3D printers. Accurately simulating the performance of real robots in a virtual environment requires modeling a variety of conditions, including the physical composition of the robots themselves. In this paper, we investigate how modeling material flexibility through the use of a passive joint affects the resulting

Jared M. Moore; Philip K. McKinley

2012-01-01

142

Analytical Study on Adhesively Bonded Joints Using Peeling Test and Symmetric Composite Models Based on Bernoulli-Euler and Timoshenko Beam Theories for Elastic and Viscoelastic Materials  

E-print Network

technology, the safety of joints in structures is still an issue, as about 70% of structure failures are initiated from joints [24]. Many studies on adhesively bonded joints have been performed using finite element methods or experimental approaches, each... To compare the experimental results of Christensen [57] with the predictions by the current model, the geometrical parameters are taken to be: L = 2 mm, ??? 0.5 mm, ??????, ?????. The adherend material is a steel (Tesa tape 4651), and the adhesive is a...

Su, Ying-Yu

2012-02-14

143

Joint Occupancy.  

ERIC Educational Resources Information Center

This annotated bibliography includes summaries of 15 articles and reports dealing with the joint use of buildings and facilities by schools and other public or private organizations. An introductory section describes the historical origins and development of the joint occupancy concept and examines the various economic and philosophical arguments…

Higham, Charlene Ellison

144

Ceramic joints  

DOEpatents

Butt joints between materials having different coefficients of thermal expansion are prepared having a reduced probability of failure of stress facture. This is accomplished by narrowing/tapering the material having the lower coefficient of thermal expansion in a direction away from the joint interface and not joining the narrow-tapered surface to the material having the higher coefficient of thermal expansion.

Miller, Bradley J. (Worcester, MA); Patten, Jr., Donald O. (Sterling, MA)

1991-01-01

145

Joining of polypropylene/polypropylene and glass fiber reinforced polypropylene composites  

NASA Astrophysics Data System (ADS)

Joining behavior of polypropylene (PP) to PP and long glass fiber reinforced polypropylene (LFT) to LFT were investigated. Adhesive bonding was used to join PP/PP. Both adhesive bonding and ultrasonic welding were used to join LFT/LFT. Single-lap shear testing and low velocity impact (LVI) testing were used to evaluate the performance of bonded structures. The two-part acrylic adhesive DP8005 was determined to be the best among the three adhesive candidates, which was attributed to its low surface energy. The impact resistance of LFT/LFT joints, normalized with respect to thickness, was higher than that of PP/PP joints because of higher stiffness of LFT/LFT joints. The stress states in the adhesive layer of adhesively bonded structures were analyzed using ANSYS and LS-DYNA to simulate the single-lap shear testing and LVI testing, respectively. The shear and peel stresses peaked at the edges of the adhesive layer. Compared to LFT/LFT joints, higher peel stress occurred in the adhesive layer in the PP/PP joints in tension. Impact response of adhesively bonded structures as evaluated by LS-DYNA showed good agreement with the experimental results. The effect of weld time and weld pressure on the shear strength of ultrasonically welded LFT/LFT was evaluated. With higher weld pressure, less time was required to obtain a complete weld. At longer weld times, lower weld pressure was required. From the 15 weld conditions studied, a weld map was obtained that provides conditions to achieve a complete weld. Nanoindentation was used to evaluate the effect of ultrasonic weld on the modulus and hardness of the PP matrix. Modulus and hardness of the PP matrix were slightly decreased by ultrasonic welding possibly due to the decrease in the molecular weight. The temperature profile in LFT/LFT in the transverse direction during ultrasonic welding was analyzed by two ANSYS-based thermal models: (a) one in which heat generated by interfacial friction was treated as a heat flux and (b) one in which heat was generated in a thin slab at the interface. The weld map obtained from the thin slab model was closer to the one obtained experimentally.

Zhang, Jianguang

146

Evaluation of a high temperature adhesive for fabricating graphite/PMR-15 polyimide structures  

NASA Technical Reports Server (NTRS)

Tests are conducted to measure shear strength, shear modulus and flatwise tensile strength of the A7F (amide-imide modified LARC-13) adhesive system. An investigation is also conducted to determine the effect of geometric material parameters, and elevated temperature on the static strength of standard joints. Single-lap and double-lap composite joints, and single, double and step lap composite to metal joints are characterized. A series of advanced joints consisting of preformed adherends, adherends with scalloped edges and joints with hybrid interface plies are tested and compared to baseline single and double-lap designs.

Hill, S. G.; Cushman, J. B.

1985-01-01

147

The mechanics and tribology of fretting fatigue with application to riveted lap joints  

NASA Astrophysics Data System (ADS)

Fretting is the synergistic combination of wear, corrosion, and fatigue damage mechanisms driven by the partial slip of contacting surfaces. The surface microslip and near-surface contact stresses associated with fretting can lead to severe reduction in service lifetimes of contacting components as diversified as bearings, turbine blades and mechanically-fastened joints, both structural and biological. This tribologically induced degradation has come under close scrutiny by those responsible for maintaining aging fleets of both commercial and military aircraft. Thus a critical need exists for predicting fretting crack nucleation in riveted aluminum. aircraft joints. Fulfilling this need requires characterizing both the near-surface mechanics and intimately-related tribology of fretting. To this end, a well characterized experimental setup has been developed to generate carefully controlled and monitored fretting contacts to investigate the nature of the near-surface conditions. Included in this investigation were in-situ observations of the fretting contact stress field via a non-invasive thermal imaging technique and a characterization of the evolution of friction under partial slip conditions. With specific qualitative and quantitative understanding of these near-surface conditions, a series of fretting fatigue experiments have been conducted to validate a mechanics-based model for predicting fretting fatigue crack nucleation. Finally, efforts have been directed toward extending this understanding of fretting crack nucleation to riveted aircraft structure through modeling of the riveting process and a related experimental program designed to link riveting process parameters and fretting damage in single-lap joint structures. This work focuses specifically on determination of the residual stresses induced during rivet installation and the morphological characterization of fretting fatigue damage in the riveted test specimens manufactured under controlled conditions.

Szolwinski, Matthew Paul

148

The effect of {+-}45{degree} fraction volume to the strength and the failure mode of riveted joints in aramid/epoxy composite materials  

SciTech Connect

The strength of riveted joint on aramid fiber reinforced plastic were investigated experimentally. Ten layers of four laminates which is different percentages of {+-}45{degree} [40%, 60%, 60% (different stacking sequence) and 80%] were prepared. The influence of width to diameter ratio [W/D] to the strength and the failure mode of the joints also observed, W/D: 2, 2.5, 3 and 3.5 was used and the edge distance to diameter ratio [E/D] were remain constant. Aramid Fiber Reinforced Plastic prepreg, style 285 (BMS-8-219D) and Hilock rivet with 4.8 mm diameter was used.

Tarigan, P.; Wirawan, B. [Indonesian Aircraft Industries Ltd., Bandung (Indonesia)

1993-12-31

149

Joint hypermobility  

Microsoft Academic Search

Joint hypermobility is an area of neglect in rheumatology. That is not to say it is overlooked by rheumatologists. It is spotted when sought, but for many unfortunate patients, here the story ends. The act of recognition becomes the goal in itself rather than the medium through which effective therapy can be provided. This chapter serves to reinforce the clinical

Rodney Grahame

2003-01-01

150

Composite  

NASA Astrophysics Data System (ADS)

Particle distribution and hot workability of an in situ Al-TiCp composite were investigated. The composite was fabricated by an in situ casting method using the self-propagating high-temperature synthesis of an Al-Ti-C system. Hot-compression tests were carried out, and power dissipation maps were constructed using a dynamic material model. Small globular TiC particles were not themselves fractured, but the clustering and grain boundary segregation of the particles contributed to the cracking of the matrix by causing the debonding of matrix/particle interfaces and providing a crack propagation path. The efficiency of power dissipation increased with increasing temperature and strain rate, and the maximum efficiency was obtained at a temperature of 723 K (450 °C) and a strain rate of 1/s. The microstructural mechanism occurring in the maximum efficiency domain was dynamic recrystallization. The role of particles in the plastic flow and the microstructure evolution were discussed.

Kim, Su-Hyeon; Cho, Young-Hee; Lee, Jung-Moo

2014-06-01

151

Analytical modeling of composite steel-concrete frame systems  

E-print Network

of reinforced concrete or composite steel shapes encased in reinforced concrete (SRC), structural steel beams, and composite beam-column joints. To facilitate the modeling of inelastic deformations in joint regions, a panel element capable of representing joint...

Atahan, Ali Osman

2012-06-07

152

Composites  

NASA Astrophysics Data System (ADS)

The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

Taylor, John G.

153

The Distribution and Composition Characteristics of Siliceous Rocks from Qinzhou Bay-Hangzhou Bay Joint Belt, South China: Constraint on the Tectonic Evolution of Plates in South China  

PubMed Central

The Qinzhou Bay-Hangzhou Bay joint belt is a significant tectonic zone between the Yangtze and Cathaysian plates, where plentiful hydrothermal siliceous rocks are generated. Here, the authors studied the distribution of the siliceous rocks in the whole tectonic zone, which indicated that the tensional setting was facilitating the development of siliceous rocks of hydrothermal genesis. According to the geochemical characteristics, the Neopalaeozoic siliceous rocks in the north segment of the Qinzhou Bay-Hangzhou Bay joint belt denoted its limited width. In comparison, the Neopalaeozoic Qinzhou Bay-Hangzhou Bay joint belt was diverse for its ocean basin in the different segments and possibly had subduction only in the south segment. The ocean basin of the north and middle segments was limited in its width without subduction and possibly existed as a rift trough that was unable to resist the terrigenous input. In the north segment of the Qinzhou Bay-Hangzhou Bay joint belt, the strata of hydrothermal siliceous rocks in Dongxiang copper-polymetallic ore deposit exhibited alternative cycles with the marine volcanic rocks, volcanic tuff, and metal sulphide. These sedimentary systems were formed in different circumstances, whose alternative cycles indicated the release of internal energy in several cycles gradually from strong to weak. PMID:24302882

Li, Hongzhong; Zhai, Mingguo; Zhang, Lianchang; Zhou, Yongzhang; Yang, Zhijun; He, Junguo; Liang, Jin; Zhou, Liuyu

2013-01-01

154

Joint inversion of shear wave travel time residuals and geoid and depth anomalies for long-wavelength variations in upper mantle temperature and composition along the Mid-Atlantic Ridge  

NASA Technical Reports Server (NTRS)

Measurements were carried out for SS-S differential travel time residuals for nearly 500 paths crossing the northern Mid-Atlantic Ridge, assuming that the residuals are dominated by contributions from the upper mantle near the surface bounce point of the reflected phase SS. Results indicate that the SS-S travel time residuals decrease linearly with square root of age, to an age of 80-100 Ma, in general agreement with the plate cooling model. A joint inversion was formulated of travel time residuals and geoid and bathymetric anomalies for lateral variation in the upper mantle temperature and composition. The preferred inversion solutions were found to have variations in upper mantle temperature along the Mid-Atlantic Ridge of about 100 K. It was calculated that, for a constant bulk composition, such a temperature variation would produce about a 7-km variation in crustal thickness, larger than is generally observed.

Sheehan, Anne F.; Solomon, Sean C.

1991-01-01

155

Joint Replacement (Finger and Wrist Joints)  

MedlinePLUS

... A-Z Hand Anatomy Find a Hand Surgeon Joint Replacement Email to a friend * required fields From * To * ... be possible to treat arthritic joints surgically, including “joint replacement” procedures. What does it mean to have a “ ...

156

Joint hypermobility.  

PubMed

Joint hypermobility is an area of neglect in rheumatology. That is not to say it is overlooked by rheumatologists. It is spotted when sought, but for many unfortunate patients, here the story ends. The act of recognition becomes the goal in itself rather than the medium through which effective therapy can be provided. This chapter serves to reinforce the clinical and epidemiological importance of a common disorder whose significance is under-appreciated and impact largely ignored. In contradistinction to our earlier chapter, published in 2000, which took for its remit the heritable disorders of connective tissue in general, the current one focuses on the commonly encountered (so-called benign) joint hypermobility syndrome, its recognition, epidemiology, clinical features and management according to the most recent literature. PMID:15123047

Hakim, Alan; Grahame, Rodney

2003-12-01

157

Investigation of the design and static behavior of cylindrical tubular composite adhesive joints utilizing the finite element method and stress-based failure theories  

NASA Astrophysics Data System (ADS)

The stress and strength behavior of cylindrical tubular adhesive joints composed of dissimilar materials was explored. This was accomplished with the finite element method (FEM) and stress-based failure theories. Also, it was shown how a design of experiments (DOE) based method can be used to objectively organize the process of optimizing joint strength by using stress-based failure criteria. The finite element program used in this work was written in-house from scratch to implement the FEM for the purpose of solving both axisymmetric and three-dimensional linear elastic governing equations of static equilibrium. The formulation of the three-dimensional model is presented, and the required operations to arrive to the axisymmetric model are also presented. The axisymmetric model is two dimensional, capable of using four and eight node quadrilateral elements. However, only four node elements are used because a mesh of eight node elements requires more memory and increased mesh refinement. The three-dimensional model is capable of using eight and twenty node brick elements, but only eight node brick elements are used for the same reason. Both of the axisymmetric and three-dimensional models calculate the nodal displacements, strains, stress values for each material, and strength values for each material. The external static loads can be individually applied, or coupled together. The outputs seem to be most useful for interpretation when plotted through-the-thickness (TTT) and along-the-length (ATL) of the joint or tube. Outputs are valid only for materials that behave linearly elastic up to (or near) failure, and the stress-based failure criteria are used to define that limit. A small laboratory-sized joint was modeled to look at the theoretical stress and strength distributions plotted along-the-length of the joint at different radial locations. These stress and strength distributions can be correlated to the type of load being applied because of unique or prominent features seen in the stress and strength distributions. The load can be a uniform temperature change, axial load, torque load, internal and external pressure, and/or bending load. A variance in the stress or strength for different joint sizes and materials is not examined closely due to the many possible combinations of these parameters.

Lambert, Michael D.

158

Composites  

NASA Astrophysics Data System (ADS)

It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-N?dza, A.; Mackiewicz, S.; Dutkiewicz, J.

2014-11-01

159

Thermal fatigue endurance of Sn3Ag0.5Cu0.5In0.05Ni and Sn2.5Ag0.8Cu0.5Sb solders in composite solder joints of LTCC\\/PWB assemblies  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the thermal fatigue endurance of two lead-free solders used in composite solder joints consisting of plastic core solder balls (PCSB) and different solder materials, in order to assess their feasibility in low-temperature cofired ceramic (LTCC)\\/printed wiring board (PWB) assemblies. Design\\/methodology\\/approach – The characteristic lifetime of these joints was determined in

O. Nousiainen; T. Kangasvieri; R. Rautioaho; J. Vähäkangas

2011-01-01

160

Joint strength in RCS frames  

E-print Network

As part of a National Science Foundation (NSF) program ics. on composite and hybrid systems at Texas A&M University, the objective of this thesis is to investigate the joint strength in reinforced column-steel beam (RCS) special moment frames...

Kirby, Cynthia Dawn

2012-06-07

161

ACEE composite structures technology  

NASA Technical Reports Server (NTRS)

The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program has made significant progress in the development of technology for advanced composites in commercial aircraft. Commercial airframe manufacturers have demonstrated technology readiness and cost effectiveness of advanced composites for secondary and medium primary components and have initiated a concerted program to develop the data base required for efficient application to safety-of-flight wing and fuselage structures. Oral presentations were compiled into five papers. Topics addressed include: damage tolerance and failsafe testing of composite vertical stabilizer; optimization of composite multi-row bolted joints; large wing joint demonstation components; and joints and cutouts in fuselage structure.

Klotzsche, M. (compiler)

1984-01-01

162

20 CFR 900.3 - Composition.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Composition. 900.3 Section 900.3 Employees' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES STATEMENT OF ORGANIZATION § 900.3 Composition. Pursuant to the Bylaws, the Joint Board consists of three...

2010-04-01

163

Joint Sealants for Horizontal Pavement Joints—Specifically Bridge Joints  

Microsoft Academic Search

The various types of materials that have been used to seal bridge joints have been reviewed. Some of the bridge engineers joint material requirements have been listed together with the advantages and disadvantages of the three most widely used bridge joint sealants being specified and used today. It is felt that the cold applied two component asphalt-modified polyurethane sealants come

Thomas J. Green

1969-01-01

164

Fatigue behavior of adhesively bonded joints  

NASA Technical Reports Server (NTRS)

The fatigue damage mechanism of composite to composite adhesively bonded joints was characterized. The mechanics of the possible modes of fatigue damage propagation in these joints when subjected to constant amplitude cyclic mechanical loading were investigated. The possible failure modes in composite bonded joints may be cyclic debonding (i.e., progressive separation of the adhesive), interlaminar damage (delamination), adherend fatigue or a combination of these. Two composite systems - graphite/epoxy adhesively bonded to graphite/epoxy and Kevlar 49/epoxy adhesively bonded to Kevlar 49/epoxy were investigated. Both composite systems consisted of quasi-isotropic lay-ups, i.e., 0 deg/-45 deg/+45 deg/90 degs. The two adhesives, employed in the study were (1) EC 3445 with cure temperature of 250 F for secondary bonding and (2) FM 300 with cure temperature of 350 F for co-cure bonding.

Mall, S.

1983-01-01

165

Pulsed radiofrequency of the composite nerve supply to the knee joint as a new technique for relieving osteoarthritic pain: a preliminary report.  

PubMed

We report a new technique for pulsed radiofrequency (PRF) of the entire nerve supply of the knee as an option in treating osteoarthritis (OA) of knee. We targeted both sensory and motor nerves supplying all the structures around the knee: joint, muscles, and skin to address the entire nociception and stiffness leading to peripheral and central sensitization in osteoarthritis. Ten patients with pain, stiffness, and loss of function in both knees were treated with ultrasonography (USG) guided PRF of saphenous, tibial, and common peroneal nerves along with subsartorial, peripatellar, and popliteal plexuses. USG guided PRF of the femoral nerve was also done to address the innervation of the quadriceps muscle. Assessment of pain (Numerical Rating Scale [NRS], pain DETECT, knee function [Western Ontario and McMaster Universities Osteoarthritis Index- WOMAC]) were documented pre and post PRF at 3 and 6 months. Knee radiographs (Kellgren-Lawrence [K-L] grading) were done before PRF and one week later. All the patients showed a sustained improvement of NRS, pain DETECT, and WOMAC at 3 and 6 months. The significant improvement of patellar position and tibio-femoral joint space was concordant with the patient's reporting of improvement in stiffness and pain. The sustained pain relief and muscle relaxation enabled the patients to optimize physiotherapy thereby improving endurance training to include the daily activities of life. We conclude that OA knee pain is a product of neuromyopathy and that PRF of the sensory and motor nerves appeared to be a safe, effective, and minimally invasive technique. The reduction of pain and stiffness improved the knee function and probably reduced the peripheral and central sensitization. PMID:25415774

Vas, Lakshmi; Pai, Renuka; Khandagale, Nishigandha; Pattnaik, Manorama

2014-12-01

166

Accounting for Class Effect Using the TIMSS 2003 Eighth-Grade Database: Net Effect of Group Composition, Net Effect of Class Process, and Joint Effect  

ERIC Educational Resources Information Center

In the scientific literature, the debate around the school and class effect is polarized, because the variance between schools and classes is explained either by school and class process or by group composition. The first aim of this article is to shed light on this debate and move beyond it by reviewing qualitative and quantitative studies…

Dumay, Xavier; Dupriez, Vincent

2007-01-01

167

Optimizations of wear resistance and toughness of hydroxyapatite nickel free stainless steel new bio-composites for using in total joint replacement  

Microsoft Academic Search

The aim of this work was to produce novel bio-composites made of hydroxyapatite and nickel free stainless steel (prepared by heat treating bone ash) and studying their mechanical properties including their tribology under various loads, toughness, and compressive and bending strengths. Different amounts of nickel free stainless steel powder (30, 40, 50 and 60wt.%) was added to this hydroxyapatite powder

M. Younesi; M. E. Bahrololoom

2010-01-01

168

Spacesuit mobility joints  

NASA Technical Reports Server (NTRS)

Joints for use in interconnecting adjacent segments of an hermetically sealed spacesuit which have low torques, low leakage and a high degree of reliability are described. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics. Linkages which restrain the joint from longitudinal distension and a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli are featured. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

Vykukal, H. C. (inventor)

1978-01-01

169

Spacesuit mobility knee joints  

NASA Technical Reports Server (NTRS)

Pressure suit mobility joints are for use in interconnecting adjacent segments of an hermetically sealed spacesuit in which low torques, low leakage and a high degree of reliability are required. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics and includes linkages which restrain the joint from longitudinal distension and includes a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

Vykukal, H. C. (inventor)

1979-01-01

170

Longitudinally Jointed Edge-Wise Compression HoneyComb Composite Sandwich Coupon Testing And Fe Analysis: Three Methods of Strain Measurement, And Comparison  

NASA Technical Reports Server (NTRS)

Three distinct strain measurement methods (i.e., foil resistance strain gages, fiber optic strain sensors, and a three-dimensional digital image photogrammetry that gives full field strain and displacement measurements) were implemented to measure strains on the back and front surfaces of a longitudinally jointed curved test article subjected to edge-wise compression testing, at NASA Goddard Space Flight Center, according to ASTM C364. The pre-test finite element analysis (FEA) was conducted to assess ultimate failure load and predict strain distribution pattern throughout the test coupon. The predicted strain pattern contours were then utilized as guidelines for installing the strain measurement instrumentations. The foil resistance strain gages and fiber optic strain sensors were bonded on the specimen at locations with nearly the same analytically predicted strain values, and as close as possible to each other, so that, comparisons between the measured strains by strain gages and fiber optic sensors, as well as the three-dimensional digital image photogrammetric system are relevant. The test article was loaded to failure (at 167 kN), at the compressive strain value of 10,000 micro epsilon. As a part of this study, the validity of the measured strains by fiber optic sensors is examined against the foil resistance strain gages and the three-dimensional digital image photogrammetric data, and comprehensive comparisons are made with FEA predictions.

Farrokh, Babak; Rahim, Nur Aida Abul; Segal, Ken; Fan, Terry; Jones, Justin; Hodges, Ken; Mashni, Noah; Garg, Naman; Sang, Alex

2013-01-01

171

Proprioception and joint stability  

Microsoft Academic Search

In the present paper the current clinical knowledge about proprioception is given for the shoulder, knee, ankle, elbow and the radiocarpal joint. Proprioceptive capabilities are decreased after joint injuries such as ACL or meniscus tears, shoulder dislocation, ankle sprain and in joints with degenerative joint disease. Some surgical procedures seem to restore the proprioceptive abilities; others do not. Elastic knee

J. Jerosch; M. Prymka

1996-01-01

172

Identifying compositional and structural changes in spongy and subchondral bone from the hip joints of patients with osteoarthritis using Raman spectroscopy  

NASA Astrophysics Data System (ADS)

Raman microspectroscopy was used to examine the biochemical composition and molecular structure of extracellular matrix in spongy and subchondral bone collected from patients with clinical and radiological evidence of idiopathic osteoarthritis of the hip and from patients who underwent a femoral neck fracture, as a result of trauma, without previous clinical and radiological evidence of osteoarthritis. The objectives of the study were to determine the levels of mineralization, carbonate accumulation and collagen quality in bone tissue. The subchondral bone from osteoarthritis patients in comparison with control subject is less mineralized due to a decrease in the hydroxyapatite concentration. However, the extent of carbonate accumulation in the apatite crystal lattice increases, most likely due to deficient mineralization. The alpha helix to random coil band area ratio reveals that collagen matrix in subchondral bone is more ordered in osteoarthritis disease. The hydroxyapatite to collagen, carbonate apatite to hydroxyapatite and alpha helix to random coil band area ratios are not significantly changed in the differently loaded sites of femoral head. The significant differences also are not visible in mineral and organic constituents' content in spongy bone beneath the subchondral bone in osteoarthritis disease.

Buchwald, Tomasz; Niciejewski, Krzysztof; Kozielski, Marek; Szybowicz, Miros?aw; Siatkowski, Marcin; Krauss, Hanna

2012-01-01

173

Evaluation of ceramic construction joints for application to high recuperative heat exchangers. Final report  

Microsoft Academic Search

Certain ceramic composite materials are potentially well suited to being used as joints and seals. These materials are attractive because of their compliance, toughness and thermal expansion properties. Various joint designs, which take advantage of the differential thermal expansion between the ceramic heat exchanger tube and the ceramic composite sleeve, were analyzed. The differential thermal growth provided a sealed joint.

1986-01-01

174

Simulation of automotive wrist pin joint and tribological studies of tin coated Al-Si alloy, metal matrix composites and nitrogen ceramics under mixed lubrication  

NASA Astrophysics Data System (ADS)

Development of automotive engines with high power output demands the application of high strength materials with good tribological properties. Metal matrix composites (MMC's) and some nitrogen ceramics are of interest to replace some conventional materials in the piston/pin/connecting rod design. A simulation study has been developed to explore the possibility to employ MMC's as bearing materials and ceramics as journal materials, and to investigate the related wear mechanisms and the possible journal bearing failure mechanisms. Conventional tin coated Al-Si alloy (Al-Si/Sn) have been studied for the base line information. A mixed lubrication model for journal bearing with a soft coating has been developed and applied to the contact and temperature analysis of the Al-Si/Sn bearing. Experimental studies were performed to reveal the bearing friction and wear behavior. Tin coating exhibited great a advantage in friction reduction, however, it suffered significant wear through pitting and debonding. When the tin wore out, the Al-Si/steel contact experienced higher friction. A cast and P/M MMC's in the lubricated contact with case hardened steel and ceramic journals were studied experimentally. Without sufficient material removal in the conformal contact situation, MMC bearings in the MMC/steel pairs gained weight due to iron transfer and surface tribochemical reactions with the lubricant additives and contact failure occurred. However, the MMC/ceramic contacts demonstrated promising tribological behavior with low friction and high wear resistance, and should be considered for new journal bearing design. Ceramics are wear resistant. Ceramic surface roughness is very crucial when the journals are in contact with the tin coated bearings. In contact with MMC bearings, ceramic surface quality and fracture toughness seem to play some important roles in affecting the friction coefficient. The wear of silicon nitride and beta sialon (A) journals is pitting due to grain boundary fracture and grain pull-out.

Wang, Qian

175

Butt Joint Tool Commissioning  

SciTech Connect

ITER Central Solenoid uses butt joints for connecting the pancakes in the CS module. The principles of the butt joining of the CICC were developed by the JAPT during CSMC project. The difference between the CSMC butt joint and the CS butt joint is that the CS butt joint is an in-line joint, while the CSMC is a double joint through a hairpin jumper. The CS butt joint has to carry the hoop load. The straight length of the joint is only 320 mm, and the vacuum chamber around the joint has to have a split in the clamp shell. These requirements are challenging. Fig.1 presents a CSMC joint, and Fig.2 shows a CS butt joint. The butt joint procedure was verified and demonstrated. The tool is capable of achieving all specified parameters. The vacuum in the end was a little higher than the target, which is not critical and readily correctable. We consider, tentatively that the procedure is established. Unexpectedly, we discover significant temperature nonuniformity in the joint cross section, which is not formally a violation of the specs, but is a point of concern. All testing parameters are recorded for QA purposes. We plan to modify the butt joining tool to improve its convenience of operation and provide all features necessary for production of butt joints by qualified personnel.

Martovetsky, N N

2007-12-06

176

Large displacement spherical joint  

DOEpatents

A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2002-01-01

177

Joint Injection/Aspiration  

MedlinePLUS

... osteoarthritis. What usually is injected into the joint space? Corticosteroids (such as methylprednisolone and triamcinolone formulated to ... for producing inflammation and pain within the joint space. Although corticosteroids may also be successfully used in ...

178

Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie & Diagonal Brace Joint Detail; Chord, Panel Post, Tie & Crossbracing Joint Detail - Dunlapsville Covered Bridge, Spanning East Fork Whitewater River, Dunlapsville, Union County, IN

179

Jointly Poisson processes  

Microsoft Academic Search

What constitutes jointly Poisson processes remains an unresolved issue. This report reviews the current state of the theory and indicates how the accepted but unproven model equals that resulting from the small time-interval limit of jointly Bernoulli processes. One intriguing consequence of these models is that jointly Poisson processes can only be positively correlated as measured by the correlation coefficient

D. H. Johnson; I. N. Goodman

2009-01-01

180

Low-Thermal-Stress Structural Joints For Dissimilar Materials  

NASA Technical Reports Server (NTRS)

Structural joint developed for attachment of hypersonic control surface to aircraft wing structure. Transmits large torque loads from composite control surface and torque tube to wing structure through metallic attachment lug and collar. Torque load transmitted from tube to collar by series of radially oriented cleats. Bearing surfaces of cleats plane passing through center-line of torque tube. Such joints accommodate differential thermal growth between parts of dissimilar materials. Potential for application to high-temperature structural joints associated with hypervelocity vehicles.

Matza, Edward C.

1990-01-01

181

Composite structural materials  

NASA Technical Reports Server (NTRS)

A multifaceted program is described in which aeronautical, mechanical, and materials engineers interact to develop composite aircraft structures. Topics covered include: (1) the design of an advanced composite elevator and a proposed spar and rib assembly; (2) optimizing fiber orientation in the vicinity of heavily loaded joints; (3) failure mechanisms and delamination; (4) the construction of an ultralight sailplane; (5) computer-aided design; finite element analysis programs, preprocessor development, and array preprocessor for SPAR; (6) advanced analysis methods for composite structures; (7) ultrasonic nondestructive testing; (8) physical properties of epoxy resins and composites; (9) fatigue in composite materials, and (10) transverse thermal expansion of carbon/epoxy composites.

Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

1979-01-01

182

Composite production riser assessment  

E-print Network

the use of the composite joints to other locations or systems. The fatigue life of the composite body is expected to greatly exceed its design life, and the most critical element is the welds between the liner and metal end pieces. Since there is wide...

Kim, Won Ki

2007-09-17

183

Joint warfare system (JWARS)  

Microsoft Academic Search

The Joint Warfare System (JWARS) is a campaign-level model of military operations that is currently being developed under contract by the Office of the Secretary of Defense (OSD) for use by OSD, the Joint Staff, the Services, and the War fighting Commands. The behavior of military forces can be simulated from ports of embarkation through to their activities in combat.

A. Simlote

2003-01-01

184

Campylobacter Prosthetic Joint Infection  

PubMed Central

A 75-year-old man was diagnosed with probable Campylobacter jejuni prosthetic knee infection after a diarrheal illness. Joint aspirate and operative cultures were negative, but PCR of prosthesis sonicate fluid was positive, as was stool culture. Nineteen additional cases of Campylobacter prosthetic joint infection reported in the literature are reviewed. PMID:24523462

Vasoo, Shawn; Schwab, Jeramy J.; Cunningham, Scott A.; Robinson, Trisha J.; Cass, Joseph R.; Berbari, Elie F.; Walker, Randall C.; Osmon, Douglas R.

2014-01-01

185

Experimental characterization of deployable trusses and joints  

NASA Technical Reports Server (NTRS)

The structural dynamic properties of trusses are strongly affected by the characteristics of joints connecting the individual beam elements. Joints are particularly significant in that they are often the source of nonlinearities and energy dissipation. While the joints themselves may be physically simple, direct measurement is often necessary to obtain a mathematical description suitable for inclusion in a system model. Force state mapping is a flexible, practical test method for obtaining such a description, particularly when significant nonlinear effects are present. It involves measurement of the relationship, nonlinear or linear, between force transmitted through a joint and the relative displacement and velocity across it. An apparatus and procedure for force state mapping are described. Results are presented from tests of joints used in a lightweight, composite, deployable truss built by the Boeing Aerospace Company. The results from the joint tests are used to develop a model of a full 4-bay truss segment. The truss segment was statically and dynamically tested. The results of the truss tests are presented and compared with the analytical predictions from the model.

Ikegami, R.; Church, S. M.; Keinholz, D. A.; Fowler, B. L.

1987-01-01

186

Resistance welding of thermosetting composite\\/thermoplastic composite joints  

Microsoft Academic Search

An investigation of the resistance welding between carbon fibre (CF)-reinforced polyetherimide (PEI) and CF-reinforced epoxy laminates is presented. A three-dimensional transient finite element model (FEM) featuring heat transfer, consolidation and thermal degradation was used for simulating the process. A hybrid interlayer made of a glass fibre (GF) fabric essentially impregnated with PEI on one side and with epoxy resin on

C. Ageorges; L. Ye

2001-01-01

187

Adhesion study of thermoplastic polyimides with Ti-6Al-4V alloy and PEEK-graphite composites  

SciTech Connect

High glass transition (e.g. 360C) melt processable thermoplastic polyimide homopolymers and poly(imide-siloxane) segmented copolymers were prepared from a number of diamines and dianhydrides via solution imidization, polydimethylsilxane segment incorporation and molecular weight control with non-reactive phthalimide end-groups. The adhesive bond performance of these polyimides was investigated as a function of molecular weight, siloxane incorporation, residual solvent, test temperature, and polyimide structure via single-lap shear samples prepared from treated Ti-6Al-4V alloy adherends and compression-molded film adhesives of scrim-cloth adhesives. The adhesive bond strengths increased greatly with siloxane-segment incorporation at 10, 20 and 30 wt% and decreased slightly with total polymer molecular weight. As the test temperature was increased, adhesive bond strength increased, decreased or showed a maximum at some temperatures depending on the polyimide structure and siloxane content. The poly(imide-30% siloxane) segmented copolymer and a miscible poly(ether-imide) also demonstrated excellent adhesive bond strength with poly(arylene ether ketone) PEEK{reg sign}-graphite composites.

Yoon Taeho.

1991-01-01

188

Hip joint replacement - series (image)  

MedlinePLUS

... pain that limits what you can do. Hip joint replacement is usually done in people age 60 and ... Hip joint replacement is surgery to replace all or part of the hip joint with a man-made or artificial ...

189

Pressure vessel flex joint  

NASA Technical Reports Server (NTRS)

An airtight, flexible joint is disclosed for the interfacing of two pressure vessels such as between the Space Station docking tunnel and the Space Shuttle Orbiter bulkhead adapter. The joint provides for flexibility while still retaining a structural link between the two vessels required due to the loading created by the internal/external pressure differential. The joint design provides for limiting the axial load carried across the joint to a specific value, a function returned in the Orbiter/Station tunnel interface. The flex joint comprises a floating structural segment which is permanently attached to one of the pressure vessels through the use of an inflatable seal. The geometric configuration of the joint causes the tension between the vessels created by the internal gas pressure to compress the inflatable seal. The inflation pressure of the seal is kept at a value above the internal/external pressure differential of the vessels in order to maintain a controlled distance between the floating segment and pressure vessel. The inflatable seal consists of either a hollow torus-shaped flexible bladder or two rolling convoluted diaphragm seals which may be reinforced by a system of straps or fabric anchored to the hard structures. The joint acts as a flexible link to allow both angular motion and lateral displacement while it still contains the internal pressure and holds the axial tension between the vessels.

Kahn, Jon B. (inventor)

1992-01-01

190

Acromioclavicular joint dislocations.  

PubMed

Acromioclavicular (AC) dislocation is a common injury especially among sportsmen. There is still a lack of consensus on whether to conserve or operate type III AC joint dislocations. Even among surgeons inclined to operate AC joint dislocations there is no unanimity on which surgical technique. There are a plethora of choices between mechanical fixation or synthetic materials or biologic anatomic reconstructions. Even among surgeons, there is a choice between open repairs and the latest-arthroscopic reconstructions. This review of AC joint dislocations intends to analyze the available surgical options, a critical analysis of existing literature, actual technique of anatomic repair, and also accompanying complications. PMID:24431027

Babhulkar, Ashish; Pawaskar, Aditya

2014-03-01

191

Anterior glenohumeral joint dislocations.  

PubMed

The glenohumeral joint is the most mobile articulation in the body and the most commonly dislocated diarthroidal joint. Anterior dislocation is by far the most common direction and can lead to instability of the glenohumeral joint, which ranges from subtle increased laxity to recurrent dislocation. Overtime, understanding of anterior shoulder dislocations and the resulting instability has improved. Likewise, significant advances in arthroscopic equipment have allowed use of the arthroscope to address anatomically the various lesions that cause instability. This article reviews the anatomy, pathophysiology, clinical evaluation, and treatment of anterior shoulder instability. PMID:18803980

Dodson, Christopher C; Cordasco, Frank A

2008-10-01

192

Improved orthopedic arm joint  

NASA Technical Reports Server (NTRS)

Joint permits smooth and easy movement of disabled arm and is smaller, lighter and less expensive than previous models. Device is interchangeable and may be used on either arm at the shoulder or at the elbow.

Dane, D. H.

1971-01-01

193

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronics Program) in solid state electronics, quantum electronics, information electronics, control and optimization, and electromagnetic phenomena is presented. Results of the research to date are summarize...

M. Tinkham

1991-01-01

194

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronics Program) in solid state electronics, quantum electronics, information electronics, control and optimization, and electromagnetic phenomena is presented. Results of the research to date are summarize...

M. Tinkham

1987-01-01

195

Joint Services Electronics Program.  

National Technical Information Service (NTIS)

An annual report of the JSEP (Joint Services Electronic Program) in solid state electronics, quantum electronics, information electronics control and optimization and electromagnetic phenomenon is presented. Results of the research to date are summarized ...

M. Tinkham

1985-01-01

196

JOINT SEMINAR FINAL REPORT  

E-print Network

evolving from the Joint Seminar. - Peer-reviewed publications (journals, contribution to anthologies, working papers, proceedings, etc.) - Non peer-reviewed publications (journals, contribution to anthologies Application guidelines Length Clarity Intelligibility Procedures (submission, review, decision) Advising

Fuchs, Clemens

197

Culture - joint fluid  

MedlinePLUS

Joint fluid culture ... fungi, or viruses grow. This is called a culture. If such microorganisms are detected, other tests may ... is no special preparation needed for the lab culture. For information on preparing for the removal of ...

198

Joint hypermobility syndrome pain  

Microsoft Academic Search

Joint hypermobility syndrome (JHS) was initially defined as the occurrence of musculoskeletal symptoms in the presence of\\u000a joint laxity and hypermobility in otherwise healthy individuals. It is now perceived as a commonly overlooked, underdiagnosed,\\u000a multifaceted, and multisystemic heritable disorder of connective tissue (HDCT), which shares many of the phenotypic features\\u000a of other HDCTs such as Marfan syndrome and Ehlers-Danlos syndrome.

Rodney Grahame

2009-01-01

199

Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie Bar, & Diagonal Brace Joint Detail; Chord, Tie Bar, & Crossbracing Joint Detail - Medora Bridge, Spanning East Fork of White River at State Route 235, Medora, Jackson County, IN

200

High pressure ceramic joint  

DOEpatents

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Ward, Michael E. (Poway, CA); Harkins, Bruce D. (San Diego, CA)

1993-01-01

201

Dissimilar metals joint evaluation  

NASA Technical Reports Server (NTRS)

Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

Wakefield, M. E.; Apodaca, L. E.

1974-01-01

202

Distal radioulnar joint injuries  

PubMed Central

Distal radioulnar joint is a trochoid joint relatively new in evolution. Along with proximal radioulnar joint, forearm bones and interosseous membrane, it allows pronosupination and load transmission across the wrist. Injuries around distal radioulnar joint are not uncommon, and are usually associated with distal radius fractures,fractures of the ulnar styloid and with the eponymous Galeazzi or Essex_Lopresti fractures. The injury can be purely involving the soft tissue especially the triangular fibrocartilage or the radioulnar ligaments. The patients usually present with ulnar sided wrist pain, features of instability, or restriction of rotation. Difficulty in carrying loads in the hand is a major constraint for these patients. Thorough clinical examination to localize point of tenderness and appropriate provocative tests help in diagnosis. Radiology and MRI are extremely useful, while arthroscopy is the gold standard for evaluation. The treatment protocols are continuously evolving and range from conservative, arthroscopic to open surgical methods. Isolated dislocation are uncommon. Basal fractures of the ulnar styloid tend to make the joint unstable and may require operative intervention. Chronic instability requires reconstruction of the stabilizing ligaments to avoid onset of arthritis. Prosthetic replacement in arthritis is gaining acceptance in the management of arthritis. PMID:23162140

Thomas, Binu P; Sreekanth, Raveendran

2012-01-01

203

Periprosthetic Joint Infections  

PubMed Central

Implantation of joint prostheses is becoming increasingly common, especially for the hip and knee. Infection is considered to be the most devastating of prosthesis-related complications, leading to prolonged hospitalization, repeated surgical intervention, and even definitive loss of the implant. The main risk factors to periprosthetic joint infections (PJIs) are advanced age, malnutrition, obesity, diabetes mellitus, HIV infection at an advanced stage, presence of distant infectious foci, and antecedents of arthroscopy or infection in previous arthroplasty. Joint prostheses can become infected through three different routes: direct implantation, hematogenic infection, and reactivation of latent infection. Gram-positive bacteria predominate in cases of PJI, mainly Staphylococcus aureus and Staphylococcus epidermidis. PJIs present characteristic signs that can be divided into acute and chronic manifestations. The main imaging method used in diagnosing joint prosthesis infections is X-ray. Computed tomography (CT) scan may assist in distinguishing between septic and aseptic loosening. Three-phase bone scintigraphy using technetium has high sensitivity, but low specificity. Positron emission tomography using fluorodeoxyglucose (FDG-PET) presents very divergent results in the literature. Definitive diagnosis of infection should be made by isolating the microorganism through cultures on material obtained from joint fluid puncturing, surgical wound secretions, surgical debridement procedures, or sonication fluid. Success in treating PJI depends on extensive surgical debridement and adequate and effective antibiotic therapy. Treatment in two stages using a spacer is recommended for most chronic infections in arthroplasty cases. Treatment in a single procedure is appropriate in carefully selected cases. PMID:24023542

Lima, Ana Lucia L.; Oliveira, Priscila R.; Carvalho, Vladimir C.; Saconi, Eduardo S.; Cabrita, Henrique B.; Rodrigues, Marcelo B.

2013-01-01

204

Instrumented Bolts Would Measure Shear Forces In Joints  

NASA Technical Reports Server (NTRS)

Bolts instrumented with strain gauges used to measure shear forces. Bolts installed in multiple-bolt lap joints to obtain data on distribution of stresses and deformations in and around joints. Strain gauges indicate share of applied load borne by each individual bolt. In original application, bolted panels made of advanced refractory composite materials designed to withstand use at temperatures up to 4,000 degrees F. Also applicable to other joint materials and measurement of shear loads in other connections such as, shear loads on shafts in pulleys or gears.

Sawyer, James Wayne; Mcwithey, Robert R.

1994-01-01

205

Joint Durability The problem?  

E-print Network

;Interfacial Zone? #12;Walking a Cliff Edge · In situ air content · w/cm · Saturation · Salts #12;Base Permeability #12;An Example #12;So · Water has to be prevented from saturating the concrete · Prevent water from ponding in the joint · Prevent water from penetrating from the base · Permeability of the concrete

206

Joints in a Cornstarch Analog  

NSDL National Science Digital Library

Joints are very important to problems in applied geology (fluid flow, slope stability), but three-dimensional exposures of simple joint sets are not readily accessible from my campus. I developed this exercise based on the experiments of Miller (2001) to give students hands-on practice describing and interpreting joints. For the exercise, I prepare a cornstarch-water mixture a few days in advance and pour it into plastic petri dishes. I add a "flaw" to each dish (typically a small pebble). As the cornstarch dries, vertical joints develop. In class, each group of 3-4 students is provided a petri dish of desiccated cornstarch. Students are asked to draw a map of the joints, paying particular attention to intersection angles. (The joints curve to intersect at 90 degrees.) They determine relative ages of the joints using abutting relationships. (Typically 3-6 generations of joints.) Students next dissect the sample and describe the surface textures of the larger joints and the location of the flaw. The cornstarch produces beautiful plumose structure (hackles). Students then interpret the joint propagation direction from the surface textures, and note the origin of the joint. (Typically, a first- or second-generation joint initiates at the flaw.) Students discuss the role of flaws in the initiation of joints in their groups.

Crider, Juliet

207

MIGRATION DES JOINTS DE GRAINS LA MIGRATION DES JOINTS INTERGRANULAIRES  

E-print Network

MIGRATION DES JOINTS DE GRAINS LA MIGRATION DES JOINTS INTERGRANULAIRES O. DIMITROV Centre d nombre de faits fondamentaux concernant la migration des joints de grains sont brièvement rappelés considérant les forces qui provoquent ou qui freinent la migration. L'évolution des modèles proposés pour

Boyer, Edmond

208

Decoupled Control of Flexure Jointed Hexapods Using Estimated Joint Space  

E-print Network

1 Decoupled Control of Flexure Jointed Hexapods Using Estimated Joint Space Mass-Inertia Matrix of flexure jointed hexapods (or Stewart platforms), a new decoupling method is proposed. The new decoupling. Keywords Vibration isolation, decoupling control, Stewart platform, precision robots, hexapod, symmetric

Chen, Yixin

209

Shoulder Joint For Protective Suit  

NASA Technical Reports Server (NTRS)

Shoulder joint allows full range of natural motion: wearer senses little or no resisting force or torque. Developed for space suit, joint offers advantages in protective garments for underwater work, firefighting, or cleanup of hazardous materials.

Kosmo, Joseph J.; Smallcombe, Richard D.

1994-01-01

210

Rolling contact orthopaedic joint design  

E-print Network

Arthroplasty, the practice of rebuilding diseased biological joints using engineering materials, is often used to treat severe arthritis of the knee and hip. Prosthetic joints have been created in a "biomimetic" manner to ...

Slocum, Alexander Henry, Jr

2013-01-01

211

Increasing the Strength of Adhesively Bonded Joints by Tapering the Adherends  

SciTech Connect

Wind turbine blades are often fabricated with composite materials. These composite blades are frequently attached to a metallic structure with an adhesive bond. For the baseline composite-to-steel joint considered in this study, failure typically occurs when the adhesive debonds from the steel adherend. Previous efforts established that the adhesive peel stresses strongly influence the strength of these joints for both single-cycle and fatigue loading. This study focused on reducing the adhesive peel stresses present in these joints by tapering the steel adherends. Several different tapers were evaluated using finite element analysis before arriving at a final design. To confirm that the selected taper was an improvement to the existing design, the baseline joint and the modified joint were tested in both compression and tension. In these axial tests, the compressive strengths of the joints with tapered adherends were greater than those of the baseline joints for both single-cycle and low-cycle fatigue. In addition, only a minor reduction in tensile strength was observed for the joints with tapered adherends when compared to the baseline joints. Thus, the modification would be expected to enhance the overall performance of this joint.

GUESS,TOMMY R.; METZINGER,KURT E.

1999-09-09

212

Double slotted socket spherical joint  

DOEpatents

A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2001-05-22

213

Phase 1 Program Joint Report  

NASA Technical Reports Server (NTRS)

This report consists of inputs from each of the Phase I Program Joint Working Groups. The Working Groups were tasked to describe the organizational structure and work processes that they used during the program, joint accomplishments, lessons learned, and applications to the International Space Station Program. This report is a top-level joint reference document that contains information of interest to both countries.

Nield, George C. (Editor); Vorobiev, Pavel Mikhailovich (Editor)

1999-01-01

214

The Challenges of Joint Attention  

Microsoft Academic Search

This paper discusses the concept of joint at- tention and the dierent skills underlying its development. We argue that joint attention is much more than gaze following or simul- taneous looking because it implies a shared intentional relation to the world. The current state-of-the-art in robotic and computational models of the dierent prerequisites of joint attention is discussed in relation

Frederic Kaplan; Verena V. Hafner

2004-01-01

215

Fatigue life prediction of bonded primary joints  

NASA Technical Reports Server (NTRS)

The validation of a proposed fatigue life prediction methodology was sought through the use of aluminum butt and scarf joint and graphite/epoxy butt joint specimens in a constant amplitude fatigue environment. The structural properties of the HYSOL 9313 adhesive system were obtained by mechanical test of molded heat adhesive specimens. Aluminum contoured double cantilever beam specimens were used to generate crack velocity versus stress intensity factor data. The specific objectives were: (1) to ascertain the feasibility of predicting fatigue failure of an adhesive in a primary bonded composite structure by incorporating linear elastic crack growth behavior; and (2) to ascertain if acoustic emission and/or compliance measurement techniques can be used to detect flaws.

Knauss, J. F.

1979-01-01

216

Joint hypermobility syndrome pain.  

PubMed

Joint hypermobility syndrome (JHS) was initially defined as the occurrence of musculoskeletal symptoms in the presence of joint laxity and hypermobility in otherwise healthy individuals. It is now perceived as a commonly overlooked, underdiagnosed, multifaceted, and multisystemic heritable disorder of connective tissue (HDCT), which shares many of the phenotypic features of other HDCTs such as Marfan syndrome and Ehlers-Danlos syndrome. Whereas the additional flexibility can confer benefits in terms of mobility and agility, adverse effects of tissue laxity and fragility can give rise to clinical consequences that resonate far beyond the confines of the musculoskeletal system. There is hardly a clinical specialty to be found that is not touched in one way or another by JHS. Over the past decade, it has become evident that of all the complications that may arise in JHS, chronic pain is arguably the most menacing and difficult to treat. PMID:19889283

Grahame, Rodney

2009-12-01

217

A Systems Biology Approach to Synovial Joint Lubrication in Health, Injury, and Disease  

PubMed Central

The synovial joint contains synovial fluid (SF) within a cavity bounded by articular cartilage and synovium. SF is a viscous fluid that has lubrication, metabolic, and regulatory functions within synovial joints. SF contains lubricant molecules, including proteoglycan-4 and hyaluronan. SF is an ultrafiltrate of plasma with secreted contributions from cell populations lining and within the synovial joint space, including chondrocytes and synoviocytes. Maintenance of normal SF lubricant composition and function are important for joint homeostasis. In osteoarthritis, rheumatoid arthritis, and joint injury, changes in lubricant composition and function accompany alterations in the cytokine and growth factor environment and increased fluid and molecular transport through joint tissues. Thus, understanding the synovial joint lubrication system requires a multi-faceted study of the various parts of the synovial joint and their interactions. Systems biology approaches at multiple scales are being used to describe the molecular, cellular, and tissue components and their interactions that comprise the functioning synovial joint. Analyses of the transcriptome and proteome of SF, cartilage, and synovium suggest that particular molecules and pathways play important roles in joint homeostasis and disease. Such information may be integrated with physicochemical tissue descriptions to construct integrative models of the synovial joint that ultimately may explain maintenance of health, recovery from injury, or development and progression of arthritis. PMID:21826801

Hui, Alexander Y.; McCarty, William J.; Masuda, Koichi; Firestein, Gary S.; Sah, Robert L.

2013-01-01

218

Joint Venture Marketing  

Microsoft Academic Search

Joint venture marketing links a for profit organization with a non-profit organization for their mutual benefit. Since American Express launched its 1981 Statue of Liberty\\/Ellis Island campaign, the strategy has proliferated among all types of health care organizations, manufacturers and even financial and educational institutions. With the successes have come concerns about non-profits having to compromise their integrity, the elimination

Nora Ganin Barnes

1991-01-01

219

Jointly Poisson processes  

Microsoft Academic Search

What constitutes jointly Poisson processes remains an unresolved issue. This\\u000areport reviews the current state of the theory and indicates how the accepted\\u000abut unproven model equals that resulting from the small time-interval limit of\\u000ajointly Bernoulli processes. One intriguing consequence of these models is that\\u000ajointly Poisson processes can only be positively correlated as measured by the\\u000acorrelation coefficient

Don H. Johnson; Ilan N. Goodman

2009-01-01

220

Prosthetic elbow joint  

NASA Technical Reports Server (NTRS)

An artificial, manually positionable elbow joint for use in an upper extremity, above-elbow, prosthetic is described. The prosthesis provides a locking feature that is easily controlled by the wearer. The instant elbow joint is very strong and durable enough to withstand the repeated heavy loadings encountered by a wearer who works in an industrial, construction, farming, or similar environment. The elbow joint of the present invention comprises a turntable, a frame, a forearm, and a locking assembly. The frame generally includes a housing for the locking assembly and two protruding ears. The forearm includes an elongated beam having a cup-shaped cylindrical member at one end and a locking wheel having a plurality of holes along a circular arc on its other end with a central bore for pivotal attachment to the protruding ears of the frame. The locking assembly includes a collar having a central opening with a plurality of internal grooves, a plurality of internal cam members each having a chamfered surface at one end and a V-shaped slot at its other end; an elongated locking pin having a crown wheel with cam surfaces and locking lugs secured thereto; two coiled compression springs; and a flexible filament attached to one end of the elongated locking pin and extending from the locking assembly for extending and retracting the locking pin into the holes in the locking wheel to permit selective adjustment of the forearm relative to the frame. In use, the turntable is affixed to the upper arm part of the prosthetic in the conventional manner, and the cup-shaped cylindrical member on one end of the forearm is affixed to the forearm piece of the prosthetic in the conventional manner. The elbow joint is easily adjusted and locked between maximum flex and extended positions.

Weddendorf, Bruce C. (inventor)

1994-01-01

221

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2011-10-01

222

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2013-10-01

223

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2012-10-01

224

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2010 CFR

...Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2010-10-01

225

Mechanical Fasteners for Advanced Composite Materials  

NASA Technical Reports Server (NTRS)

Advanced composite materials, which are increasingly being used to build aircraft, have different properties than the metals they replace. Fasteners intended for composite-material joints must be designed and selected to allow for these differences. For example, blind fasteners (one-sided access) used to assemble composite-to-composite joints have been redesigned to expand to larger diameters to resist pull-through and cocking failures. The fastener designs needed for composite materials are reviewed. Topics discussed are: galvanic corrosion, pull-through resistance, fastener rotation, installation damage, fastener galling and conductivity. A blind fastener recently developed by SPS Technologies is described to show how these requirements are incorporated.

Landt, R. C.

1985-01-01

226

Laboratory characterization of rock joints  

SciTech Connect

A laboratory characterization of the Apache Leap tuff joints under cyclic pseudostatic and dynamic loads has been undertaken to obtain a better understanding of dynamic joint shear behavior and to generate a complete data set that can be used for validation of existing rock-joint models. Study has indicated that available methods for determining joint roughness coefficient (JRC) significantly underestimate the roughness coefficient of the Apache Leap tuff joints, that will lead to an underestimation of the joint shear strength. The results of the direct shear tests have indicated that both under cyclic pseudostatic and dynamic loadings the joint resistance upon reverse shearing is smaller than that of forward shearing and the joint dilation resulting from forward shearing recovers during reverse shearing. Within the range of variation of shearing velocity used in these tests, the shearing velocity effect on rock-joint behavior seems to be minor, and no noticeable effect on the peak joint shear strength and the joint shear strength for the reverse shearing is observed.

Hsiung, S.M.; Kana, D.D.; Ahola, M.P.; Chowdhury, A.H.; Ghosh, A. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1994-05-01

227

New plastic joints for plastic orthoses.  

PubMed

Plastic joints for orthoses have more advantages than metal joints. They are lightweight, noiseless comfortable to use, rust proof, corrosion free, and radiolucent. Two types of plastic joints were developed by the authors, one for the ankle joint and the other for the knee joint, elbow joint or hip joint. Polypropylene was chosen as the joint material because of its appropriate flexibility and toughness. PMID:7079105

Watanabe, H; Kutsuna, T; Morinaga, H; Okabe, T

1982-04-01

228

Improving the fatigue resistance of adhesive joints in laminated wood structures  

Microsoft Academic Search

The premature fatigue failure of a laminated wood\\/epoxy test beam containing a cross-section finger joint was the subject of a multidisciplinary investigation to assess and advance the technology of adhesive joints in composite wood structures. This investigation, which has wide-spread applicability to all adhesively bonded joints, included (1) analysis of the data collected during fatigue testing, (2) microscopic examination of

T. L. Laufenberg; B. H. River; L. L. Murmanis; A. W. Christiansen

1988-01-01

229

Joint Video and Text Parsing for Understanding Events and Answering Queries  

E-print Network

1 Joint Video and Text Parsing for Understanding Events and Answering Queries Kewei Tu, Meng Meng a parse graph that represents the compositional structures of spatial information (objects and scenes of the parse graphs. We present a probabilistic generative model for joint parsing that captures the relations

Zhu, Song Chun

230

Joint hypermobility syndrome.  

PubMed

Although perceived as a rare condition, joint hypermobility syndrome is common. Its prevalence in rheumatology clinics is extremely high. Early estimates suggest that it may be the most common of all rheumatologic conditions. The problem lies in the general lack of awareness of the syndrome, its means of recognition, and the resultant failure to diagnose it correctly when present. It is a worldwide problem. This article provides an overview of hypermobility and hypermobility syndrome, stressing its multisystemic nature and the negative impact that it may have on quality of life, with particular reference to gastrointestinal involvement. PMID:23597972

Fikree, Asma; Aziz, Qasim; Grahame, Rodney

2013-05-01

231

Joint services electronics program  

NASA Astrophysics Data System (ADS)

This report is the Annual Progress Report for Joint Services Electronics Program Contract N00014-84-K-0327 for the Faculty of the Edward L. Ginzton Laboratory of Stanford University (S.E. Harris, Director). The report includes contributions on four units: (1) (Unit 85-1: Processor D.M. Bloom) Picosecond Optical Measurements; (2) Unit 85-2: Processor R.L. Byer) Optical and Nonlinear Optical Studies of Single Crystal Fibers; (3) (Unit 85-3: Professor G.S. Kino) Very High Frequency Signal Processing Techniques; (4) Unit 85-4: Professor C.F. Quate) Metal-Vacuum-Metal Tunneling or scanned Tunneling Microscopy.

Harris, S. E.; Bloom, D. M.; Byer, R. L.; Kino, G. S.; Quate, C. F.

1985-07-01

232

Fluid movement and joint capsule strains due to flexion in rabbit knees  

PubMed Central

Diarthrodial joints are freely moveable joints containing synovial fluid (SF) within a connective tissue joint capsule that allows for low-friction and low-wear articulation of the cartilaginous ends of long bones. Biomechanical cues from joint articulation regulate synoviocyte and cartilage biology via joint capsule strain, in turn altering the composition of SF. Joint flexion is clinically associated with pain in knees with arthritis and effusion, with the nociception possibly originating from joint capsule strain. The hypothesis of this study was that knee fluid volume distribution and joint capsule strain are altered with passive flexion in the rabbit model. The aims were to (a) determine the volume distribution of fluid in the joint at different total volumes and with flexion of rabbit knees ex vivo, (b) correlate the volume distribution for the ex vivo model to in vivo data, and (c) determine the strains at different locations in the joint capsule with flexion. During knee flexion, ~20% of anteriorly located joint fluid moved posteriorly, correlating well with the fluid motion observed in in vivo joints. Planar joint capsule principal strains were ~100% (tension) in the proximal–distal direction and ~ ?40% (shortening) in the circumferential direction, relative to the femur axis and 30° strain state. The joint capsule strains with flexion are consistent with the mechanics of the tendons and ligaments from which the capsule tissue is derived. The movement and mixing of SF volume with flexion determine the mechanical and biological fluid environment within the knee joint. Joint fluid movement and capsular strains affect synovial cell biology and likely modulate trans-synovial transport. PMID:21945567

McCarty, William J.; Masuda, Koichi; Sah, Robert L.

2011-01-01

233

Jointly Sponsored Research Program  

SciTech Connect

U.S. Department of Energy (DOE) Cooperative Agreement DE-FC26-98FT40321 funded through the Office of Fossil Energy and administered at the National Energy Technology Laboratory (NETL) supported the performance of a Jointly Sponsored Research Program (JSRP) at the Energy & Environmental Research Center (EERC) with a minimum 50% nonfederal cost share to assist industry in commercializing and effectively applying highly efficient, nonpolluting energy systems that meet the nation's requirements for clean fuels, chemicals, and electricity in the 21st century. The EERC in partnership with its nonfederal partners jointly performed 131 JSRP projects for which the total DOE cost share was $22,716,634 (38%) and the nonfederal share was $36,776,573 (62%). Summaries of these projects are presented in this report for six program areas: (1) resource characterization and waste management, (2) air quality assessment and control, (3) advanced power systems, (4) advanced fuel forms, (5) value-added coproducts, and (6) advanced materials. The work performed under this agreement addressed DOE goals for reductions in CO{sub 2} emissions through efficiency, capture, and sequestration; near-zero emissions from highly efficient coal-fired power plants; environmental control capabilities for SO{sub 2}, NO{sub x}, fine respirable particulate (PM{sub 2.5}), and mercury; alternative transportation fuels including liquid synfuels and hydrogen; and synergistic integration of fossil and renewable resources.

Everett A. Sondreal; John G. Hendrikson; Thomas A. Erickson

2009-03-31

234

Joint collaborative technology experiment  

NASA Astrophysics Data System (ADS)

Use of unmanned systems is rapidly growing within the military and civilian sectors in a variety of roles including reconnaissance, surveillance, explosive ordinance disposal (EOD), and force-protection and perimeter security. As utilization of these systems grows at an ever increasing rate, the need for unmanned systems teaming and inter-system collaboration becomes apparent. Collaboration provides a means of enhancing individual system capabilities through relevant data exchange that contributes to cooperative behaviors between systems and enables new capabilities not possible if the systems operate independently. A collaborative networked approach to development holds the promise of adding mission capability while simultaneously reducing the workload of system operators. The Joint Collaborative Technology Experiment (JCTE) joins individual technology development efforts within the Air Force, Navy, and Army to demonstrate the potential benefits of interoperable multiple system collaboration in a force-protection application. JCTE participants are the Air Force Research Laboratory, Materials and Manufacturing Directorate, Airbase Technologies Division, Force Protection Branch (AFRL/RXQF); the Army Aviation and Missile Research, Development, and Engineering Center Software Engineering Directorate (AMRDEC SED); and the Space and Naval Warfare Systems Center - Pacific (SSC Pacific) Unmanned Systems Branch operating with funding provided by the Joint Ground Robotics Enterprise (JGRE). This paper will describe the efforts to date in system development by the three partner organizations, development of collaborative behaviors and experimentation in the force-protection application, results and lessons learned at a technical demonstration, simulation results, and a path forward for future work.

Wills, Michael; Ciccimaro, Donny; Yee, See; Denewiler, Thomas; Stroumtsos, Nicholas; Messamore, John; Brown, Rodney; Skibba, Brian; Clapp, Daniel; Wit, Jeff; Shirts, Randy J.; Dion, Gary N.; Anselmo, Gary S.

2009-05-01

235

Metal to ceramic sealed joint  

DOEpatents

A metal to ceramic sealed joint which can withstand wide variations in temperature and maintain a good seal is provided for use in a device adapted to withstand thermal cycling from about 20 to about 1000 degrees C. The sealed joint includes a metal member, a ceramic member having an end portion, and an active metal braze forming a joint to seal the metal member to the ceramic member. The joint is positioned remote from the end portion of the ceramic member to avoid stresses at the ends or edges of the ceramic member. The sealed joint is particularly suited for use to form sealed metal to ceramic joints in a thermoelectric generator such as a sodium heat engine where a solid ceramic electrolyte is joined to metal parts in the system.

Lasecki, John V. (Livonia, MI); Novak, Robert F. (Farmington Hills, MI); McBride, James R. (Ypsilanti, MI)

1991-01-01

236

Rotary Joint for Heat Transfer  

NASA Technical Reports Server (NTRS)

Rotary joint exchanges heat between two heat pipes - one rotating and one stationary. Joint accommodates varying heat loads with little temperature drop across interface. According to concept, heat pipe enters center of disklike stationary section of joint. There, wicks in central artery of heat pipe separate into multiple strands that lead to concentric channels on rotaryinterface side of stationary disk. Thin layer of liquid sodium/potassium alloy carries heat from one member of rotary joint to other. Liquid conducts heat efficiently while permitting relative motion between members. Polypropylene rings contain liquid without interfering with rotation.

Shauback, R.

1986-01-01

237

UV-cured adhesives for carbon fiber composite applications  

NASA Astrophysics Data System (ADS)

Carbon fiber composite materials are increasingly used in automobile, marine, and aerospace industries due to their unique properties, including high strength, high stiffness and low weight. However, due to their brittle characteristic, these structures are prone to physical damage, such as a bird strike or impact damage. Once the structure is damaged, it is important to have fast and reliable temporary repair until the permanent repair or replacement can take place. In this dissertation, UV-based adhesives were used to provide a bonding strength for temporary repair. Adhesively bonded patch repair is an efficient and effective method for temporary repair. In this study, precured patches (hard patches) and dry fabric patches with laminating resins (soft patches) were performed. UV-based epoxy adhesives were applied to both patch repair systems. For precured patch repair, the bonding strengths were investigated under different surface treatments for bonding area and different adhesives thicknesses. The shear stresses of different UV exposure times and curing times were tested. Besides, the large patch repair was investigated as well. For soft patch repair, the hand wet lay-up was applied due to high viscosity of UV resins. A modified single lap shear testing (ASTM D5868) was applied to determine the shear stress. The large patches used fiber glass instead of carbon fiber to prove the possibility of repair with UV epoxy resin by hand wet lay-up process. The hand lay-up procedure was applied and assisted by vacuum pressure to eliminate the air bubbles and consolidate the patches. To enhance the bonding strength and effective soft patch repair, vacuum assisted resin transferring molding (VaRTM) is the better option. However, only low viscosity resins can be operated by VaRTM. Hence, new UV-based adhesives were formulated. The new UV-based adhesives included photoinitiator (PI), epoxy and different solvents. Solvents were used to compound the photoinitiator into epoxy monomer. Acetone, tetrahydrofuran (THF) and chloroform were used as well as their anhydrous solvents. The UV exposure times and curing times of new UV-based resins were tested. FT-IR, DSC and DMA were used to investigate structure, glass transition temperatures(Tg) and properties of polymer. In summary, the UV-based adhesive was applied to adhesively bonded hard patch and soft patch repair. In addition, new UV-based resins were formulated for the VaRTM process. The in-field repair can be effective and efficient by using UV adhesives.

Lu, Hsiao-Chun

238

[Prosthetics of metacarpophalangeal joints].  

PubMed

Only a few of the large number of implants developed during the last decades for replacement of the metacarpophalangeal (MCP) joint have proven to be reliable. The rates of loosening and mechanical failure of almost all types of constrained prostheses are so high that their use cannot be recommended at present. For more than 40 years silicone arthroplasty according to Swanson has been regarded as the gold standard in the prosthetic replacement of the MCP joint. In long-term studies this device provided good pain relief and a lasting correction of preoperative ulnar deviation. The degree of patient satisfaction continues to be high after more than 10 years. With the NeuFlex spacer, a modification of the original Swanson implant, a better range of motion and a reduction of wear-related problems is expected. In this study the results of 130 NeuFlex spacers after a mean time of 3.6 years were examined and 82% of the patients were completely pain free. The mobility of the joints improved from 40 degrees preoperatively to 54 degrees after 3.6 years. Radiologically periprosthetic erosions or osteolyses were seen in approximately 15% of implants. A minimal sinking of the stems developed in 24%, a massive one in 6% and 13% of the spacers were broken. Thus the use of the NeuFlex implant resulted in a better range of motion compared to the Swanson spacer, but the problem of radiological appearance remained unchanged. For unlinked prostheses sufficient soft tissue stability is mandatory as well as wear-resistant surface materials. The pyrocarbon prosthesis according to Beckenbaugh is the only implant for which long-term results are available. In a prospective study we evaluated 28 Ascension pyrocarbon prostheses with a mean follow-up of 4 years. Stability was not found to be a problem. Subjective results were satisfactory, the range of motion remained unchanged, however 46% of prosthesis stems exhibited radiolucent seams, 7 prostheses (25%) were rated as loose and 5 of those had to be replaced by a silicone implant. Use of the implant was abandoned, as it was unreliable regarding bony fixation. There are promising concepts in some new prostheses but independent data are still lacking. PMID:17717677

Hilker, A; Miehlke, R-K; Schmidt, K

2007-09-01

239

Healthy Joints Matter What exactly is a joint?  

E-print Network

diet, avoiding injuries, and getting plenty of sleep will help you stay healthy and keep your joints be triggered by an injury to a joint, such as a knee injury that damages the cartilage. · Rheumatoid arthritis arthritis is a term often used to describe arthritis in children. Children can develop almost all types

Baker, Chris I.

240

Metal-on-metal hip joint tribology.  

PubMed

The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described. PMID:16669380

Dowson, D; Jin, Z M

2006-02-01

241

Passive Ball Capture Joint  

NASA Technical Reports Server (NTRS)

A passive ball capture joint has a sleeve with a plurality of bores distributed about a circumference thereof and formed therethrough at an acute angle relative to the sleeve's longitudinal axis. A spring-loaded retainer is slidingly fitted in each bore and is biased such that, if allowed, will extend at least partially into the sleeve to retain a ball therein. A ring, rotatably mounted about the bores, has an interior wall defining a plurality of shaped races that bear against the spring-loaded retainers. A mechanized rotational force producer is coupled to the ring. The ring can be rotated from a first position (that presses the retainers into the sleeve to lock the ball in place) to a second position (that allows the retainers to springback out of the sleeve to release the ball).

Cloyd, Richard A. (Inventor); Bryan, Thomas C. (Inventor)

2003-01-01

242

Teflon-packed flexible joint  

NASA Technical Reports Server (NTRS)

Teflon-packed flexible joint separates the movement of the shaker from the liquid nitrogen hose during the ground testing of cryogenic zero-g equipment. The joint allows the hose to lie on the floor in a stationary position as the shaker moves back and forth, thus, the hose is not subject to violent motion.

Belmont, G. E.

1969-01-01

243

Joint mobility and motor development  

Microsoft Academic Search

The association of joint hypermobility and motor development was sequentially investigated in 715 infants from the ages of 8 to 14 months. Seven joints were evaluated for mobility, and each infant underwent a physical and neurological examination. Parents were given a Denver Developmental Parents' Questionnaire. All subjects with a general developmental delay, systemic illness or syndrome were excluded. The infants

M Jaffe; E Tirosh; A Cohen; Y Taub

1988-01-01

244

Light alloys plates welded joints  

Microsoft Academic Search

In the field described by the topics of the title, there are different ways to achieve the joint. One of them is the spot cold pressure welding. First, the paper presents the experimental results regarding the sharing strength test of the spot cold welded joints. The purpose of the research was to analyze different variant of welding, in order to

Valeriu Georgescu; Mihaela Iordachescu; Bogdan Georgescu

245

Exercise and the Knee Joint.  

ERIC Educational Resources Information Center

This report by the President's Council on Physical Fitness and Sports examines the effects of various forms of physical exercise on the knee joint which, because of its vulnerability, is especially subject to injury. Discussion centers around the physical characteristics of the joint, commonly used measurements for determining knee stability,…

Clarke, H. Harrison, Ed.

1976-01-01

246

Composite drill pipe  

DOEpatents

A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

Leslie, James C. (Fountain Valley, CA); Leslie, II, James C. (Mission Viejo, CA); Heard, James (Huntington Beach, CA); Truong, Liem (Anaheim, CA), Josephson; Marvin (Huntington Beach, CA), Neubert; Hans (Anaheim, CA)

2008-12-02

247

Micromechanical model for anisotropic rock joints  

Microsoft Academic Search

Force-deformation relationships of rock joints are important in the study of mechanical behavior of fractured or jointed rocks. Experimental studies have shown that rock joints often exhibit deformation hardening and anisotropic behavior under shearing loads. This paper focuses upon the mathematical modeling of force-deformation behavior of anisotropic rock joints by explicitly considering interaction of asperities on a joint surface. Elastic

Anil Misra

1999-01-01

248

Space Station alpha joint bearing  

NASA Technical Reports Server (NTRS)

Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

1987-01-01

249

Proceedings of the 27th Ris International Symposium on Materials Science  

E-print Network

of structures that develop large-scale damage along adhesively bonded joints. The approach is based on the use to characterise the strength of adhesively bonded joints. Never the less, the strength values obtained from single lap joints can only be used for qualitatively ranking of the bond strength of adhesive

250

Introduction Joints and the muscle articulation  

E-print Network

: biomechanics, Cephalopoda, electromyography, mus the joint. The morphology of the articulating surfaces and joint capsule controls the range of motion segments of smaller insects use this mechanism. The joint studied here, termed a `muscle articulation

Kier, William M.

251

11 CFR 9034.8 - Joint fundraising.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Joint fundraising. 9034.8 Section 9034.8 Federal... ENTITLEMENTS § 9034.8 Joint fundraising. (a) General. Nothing...this subchapter may engage in joint fundraising with other candidates, political...

2011-01-01

252

11 CFR 9034.8 - Joint fundraising.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Joint fundraising. 9034.8 Section 9034.8 Federal... ENTITLEMENTS § 9034.8 Joint fundraising. (a) General. Nothing...this subchapter may engage in joint fundraising with other candidates, political...

2010-01-01

253

Musculoskeletal US: examining the joints.  

PubMed

Musculoskeletal ultrasound (US) is an excellent tool to diagnose muscle, tendon and ligament injuries, cystic structures and peripheral nerve compression, as well as soft tissue masses, without the risk of ionizing radiation. Musculoskeletal US is now routinely used by a growing number of rheumatology and sports medicine centres throughout UK. In standard clinical practice, US has an extremely useful application in differentiating fluid from soft tissue and identifying the severity of joint inflammation. The work described in this article was carried out to assess patients' feedback regarding the use of US guidance for intra-articular injections and/or the removal of fluid from their inflamed knee joints in a nurse-led clinic. Nineteen patients who had US-guided knee joint injection/aspiration in the clinic were asked to complete a questionnaire regarding their satisfaction with the procedure, and to rate their joint pain and patient global assessment (using numerical visual analogue scale) before the US-guided procedure, and 1 month after. Results revealed a significant improvement (p<0.001) of the joint injection outcome measures and the patients' satisfaction of the US-guided procedure. Therefore, musculoskeletal US can improve two fundamental clinical skills: the clinical diagnosis of joint inflammation, and the accuracy of joint injection/aspiration. This study supports the concept that incorporating musculoskeletal US into clinical practice leads to significant improvements in patient care. It also reveals that US-guided procedures are appreciated by patients. PMID:22584929

El Miedany, Yasser

254

Common Bolted Joint Analysis Tool  

NASA Technical Reports Server (NTRS)

Common Bolted Joint Analysis Tool (comBAT) is an Excel/VB-based bolted joint analysis/optimization program that lays out a systematic foundation for an inexperienced or seasoned analyst to determine fastener size, material, and assembly torque for a given design. Analysts are able to perform numerous what-if scenarios within minutes to arrive at an optimal solution. The program evaluates input design parameters, performs joint assembly checks, and steps through numerous calculations to arrive at several key margins of safety for each member in a joint. It also checks for joint gapping, provides fatigue calculations, and generates joint diagrams for a visual reference. Optimum fastener size and material, as well as correct torque, can then be provided. Analysis methodology, equations, and guidelines are provided throughout the solution sequence so that this program does not become a "black box:" for the analyst. There are built-in databases that reduce the legwork required by the analyst. Each step is clearly identified and results are provided in number format, as well as color-coded spelled-out words to draw user attention. The three key features of the software are robust technical content, innovative and user friendly I/O, and a large database. The program addresses every aspect of bolted joint analysis and proves to be an instructional tool at the same time. It saves analysis time, has intelligent messaging features, and catches operator errors in real time.

Imtiaz, Kauser

2011-01-01

255

Compliant Prosthetic Or Robotic Joint  

NASA Technical Reports Server (NTRS)

Rotation partly free and partly restrained by resilience and damping. Joint includes U-shaped x- and y-axis frames joined by cables that cross in at center piece. The y-axis frame rotates about y-axis on roller bearing within predetermined angular range. The y-axis frame rotates slightly farther when arm strikes stop, because cables can twist. This mimics compliant resistance of knee joint reaching limit of its forward or backward motion. Used in prosthetic device to replace diseased or damage human joint, or in robot linkage to limit movement and cushion overloads.

Kerley, James J.; Eklund, Wayne D.

1989-01-01

256

Imaging of the patellofemoral joint.  

PubMed

The patellofemoral (PF) joint is a complex articulation, with interplay between the osseous and soft tissue structures to maintain the balance between knee mobility and stability. Disorders of the PF joint can be a source of anterior knee pain (AKP). In this article, radiographic and magnetic resonance imaging of the PF joint are reviewed, including normal anatomy, imaging techniques, and imaging-based measurements. Common imaging findings associated with AKP are reviewed, including symptomatic normal variants, tendinopathy, apophysitis, osteoarthritis, chondromalacia patella, trochlear dysplasia, excessive lateralization of tibial tuberosity, patellar maltracking, patellar dislocation and fractures, anterior bursitis, Morel-Lavallée effusions, and fat pad edema. PMID:24993408

Thomas, Stephen; Rupiper, David; Stacy, G Scott

2014-07-01

257

A distributed interactive composition tool  

Microsoft Academic Search

As an interactive, computerized, network oriented musical composition tool, Rabisco allows users to create stream of MIDI data in real-time by drawing simple sketches using a simple 2-D graphical tablet (pad). Utilizing a client-server architecture, Rabisco allows virtual joint compositions where several musicians interact over the network or the internet, each using a Rabisco client. Current applications includes Distance Learning,

Márcio O. Costa; Jônatas Manzolli; Dan Sharoni

2002-01-01

258

Shock structuring due to fabrication joints in targets  

NASA Astrophysics Data System (ADS)

The use of copper-doped beryllium ablators on National Ignition Facility [J. A. Paisner et al., Laser Focus World 30, 75 (1994)] targets, in place of plastic, can require the bonding together of hemispheres with a joint of differing composition. Indirect drive experiments have been conducted on the Nova laser [J. L. Emmet, W. F. Krupke, and J. B. Trenholme, Sov. J. Quantum Electron. 13, 1 (1983)], and the resulting shock structuring compared with code simulations. It is concluded that one of the available codes, the RAGE code [R. M. Baltrusaitis et al., Phys. Fluids 8, 2471 (1996)] provides useful insight into the effect of joints. This code is then employed to obtain a physical picture of the shock front nonuniformity in terms of a secondary rarefaction and an oblique shock interacting with the main shock that propagates in the absence of the joint. A simple analysis reinforces this picture.

Goldman, S. R.; Caldwell, S. E.; Wilke, M. D.; Wilson, D. C.; Barnes, Cris W.; Hsing, W. W.; Delamater, N. D.; Schappert, G. T.; Grove, J. W.; Lindman, E. L.; Wallace, J. M.; Weaver, R. P.; Dunne, A. M.; Edwards, M. J.; Graham, P.; Thomas, B. R.

1999-08-01

259

The complexity of joint computation  

E-print Network

Joint computation is the ubiquitous scenario in which a computer is presented with not one, but many computational tasks to perform. A fundamental question arises: when can we cleverly combine computations, to perform them ...

Drucker, Andrew Donald

2012-01-01

260

Joint probabilities and quantum cognition  

E-print Network

In this paper we discuss the existence of joint probability distributions for quantum-like response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

J. Acacio de Barros

2012-06-26

261

Joint probabilities and quantum cognition  

SciTech Connect

In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

Acacio de Barros, J. [Liberal Studies, 1600 Holloway Ave., San Francisco State University, San Francisco, CA 94132 (United States)

2012-12-18

262

Biofluid lubrication for artificial joints  

E-print Network

. [33]. It is comprised of three areas as follows: lubrication, friction, and wear. In the natural human joint during lubrication, the same principle applies. The frictional patterns of bearing are adapted by the existence of a lubricant [33.... [33]. It is comprised of three areas as follows: lubrication, friction, and wear. In the natural human joint during lubrication, the same principle applies. The frictional patterns of bearing are adapted by the existence of a lubricant [33...

Pendelton, Alice Mae

2009-05-15

263

Ceramic vane drive joint  

DOEpatents

A variable geometry gas turbine has an array of ceramic composition vanes positioned by an actuating ring coupled through a plurality of circumferentially spaced turbine vane levers to the outer end of a metallic vane drive shaft at each of the ceramic vanes. Each of the ceramic vanes has an end slot of bow tie configuration including flared end segments and a center slot therebetween. Each of the vane drive shafts has a cross head with ends thereof spaced with respect to the sides of the end slot to define clearance for free expansion of the cross head with respect to the vane and the cross head being configured to uniformly distribute drive loads across bearing surfaces of the vane slot.

Smale, Charles H. (Indianapolis, IN)

1981-01-01

264

Low temperature joining of ceramic composites  

DOEpatents

A method of joining similar or dissimilar ceramic and ceramic composite materials, such as SiC continuous fiber ceramic composites, at relatively low joining temperatures uses a solventless, three component bonding agent effective to promote mechanical bond toughness and elevated temperature strength to operating temperatures of approximately 1200 C. The bonding agent comprises a preceramic precursor, an aluminum bearing powder, such as aluminum alloy powder, and mixtures of aluminum metal or alloy powders with another powder, and boron powder in selected proportions. The bonding agent is disposed as an interlayer between similar or dissimilar ceramic or ceramic composite materials to be joined and is heated in ambient air or inert atmosphere to a temperature not exceeding about 1200 C to form a strong and tough bond joint between the materials. The bond joint produced is characterized by a composite joint microstructure having relatively soft, compliant aluminum bearing particulate regions dispersed in a ceramic matrix. 3 figs.

Barton, T.J.; Anderson, I.E.; Ijadi-Maghsoodi, S.; Nosrati, M.; Unal, O.

1999-07-13

265

Low temperature joining of ceramic composites  

DOEpatents

A method of joining similar or dissimilar ceramic and ceramic composite materials, such as SiC continuous fiber ceramic composites, at relatively low joining temperatures uses a solventless, three component bonding agent effective to promote mechanical bond toughness and elevated temperature strength to operating temperatures of approximately 1200 degrees C. The bonding agent comprises a preceramic precursor, an aluminum bearing powder, such as aluminum alloy powder, and mixtures of aluminum metal or alloy powders with another powder, and and boron powder in selected proportions. The bonding agent is disposed as an interlayer between similar or dissimilar ceramic or cermaic composite materials to be joined and is heated in ambient air or inert atmosphere to a temperature not exceeding about 1200 degrees C. to form a strong and tough bond joint between the materials. The bond joint produced is characterized by a composite joint microstructure having relatively soft, compliant aluminum bearing particulate regions dispersed in a ceramic matrix.

Barton, Thomas J. (Ames, IA); Anderson, Iver E. (Ames, IA); Ijadi-Maghsoodi, Sina (Ames, IA); Nosrati, Mohammad (Ames, IA); Unal, Ozer (Ames, IA)

2001-04-10

266

Structure and properties of welded joints from various titanium alloys  

Microsoft Academic Search

Metallographic, x-ray diffraction, x-ray microspectral and hardness testing techniques have been used to examine the changes in the structure, phase composition, microhardness and the distribution of alloying elements in the parent metal and in the heat affected zone and in the seams of welded joints formed from various titanium alloys (VT6-OT4, VT6-VT20, VT23-OT4, VT23-VT6, VT23-VT19 and VT23-VT32) in the post

A. A. Popov; A. G. Illarionov; M. A. Khorev; N. A. Drozdova

1992-01-01

267

49 CFR 213.351 - Rail joints.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Rail joints. 213.351 Section 213.351 Transportation...Operations at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2012-10-01

268

49 CFR 213.351 - Rail joints.  

Code of Federal Regulations, 2010 CFR

...Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.351 Section 213.351 Transportation...Operations at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2010-10-01

269

49 CFR 213.351 - Rail joints.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.351 Section 213.351 Transportation...Operations at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2011-10-01

270

49 CFR 213.351 - Rail joints.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.351 Section 213.351 Transportation...Operations at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2013-10-01

271

Management of acromioclavicular joint injuries.  

PubMed

Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (?type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these constructs are necessary to avoid loss of reduction and creep with cyclic loading. PMID:24382728

Li, Xinning; Ma, Richard; Bedi, Asheesh; Dines, David M; Altchek, David W; Dines, Joshua S

2014-01-01

272

Brazing of sheet composite materials with aluminium matrix  

NASA Astrophysics Data System (ADS)

The technique of brazing composite sheets with an aluminum matrix is investigated for Al matrices with either stainless steel or boron fibers. Brazing is compared to other joining techniques, and the relationship between heating and pressure levels is studied by characterizing the joint qualities microscopically. Solder composition is similarly analyzed, and brazing recommendations are given for ranges of joint sizes. Calculations of the temperature fields for the brazing of these composite materials yield specific-heat input data. Optimal brazing modes thus derived for the Al-matrix composites yield joints free of the intermetallide phases that degrade the performance of brazed structures. The tensile strength of the optimized joints is shown to be good relative to the strength of the original composites with Al matrices.

Khorunov, V. F.; Kuchuk-Iatsenko, V. S.; Dykhno, I. S.; Kasatkina, N. V.

273

Creep properties of eutectic Sn3.5Ag solder joints reinforced with mechanically incorporated Ni particles  

Microsoft Academic Search

The creep deformation behavior of eutectic Sn-3.5Ag based Ni particle rein forced composite solder joints was investigated.\\u000a The Ni particle reinforced composite solder was prepared by mechanically dispersing 15 vol.% of Ni particles into eutectic\\u000a Sn-3.5Ag solder paste. Static-loading creep tests were carried out on solder joint specimens at 25 C, 65 C, and 105 C, representing\\u000a homologous temperatures ranging

F. Guo; J. Lee; J. P. Lucas; K. N. Subramanian; T. R. Bieler

2001-01-01

274

Research advances in nano-composite solders  

Microsoft Academic Search

Recently, nano-composite solders have been developed in the electronic packaging materials industry to improve the creep and thermo-mechanical fatigue resistance of solder joints to be used in service at high temperatures and under thermo-mechanical fatigue conditions. This paper reviews the driving force for the development of nano-composite solders in the electronic packaging industry and the research advances of the composite

J. Shen; Y. C. Chan

2009-01-01

275

Elasto-Plastic Analysis of Tee Joints Using HOT-SMAC  

NASA Technical Reports Server (NTRS)

The Higher Order Theory - Structural/Micro Analysis Code (HOT-SMAC) software package is applied to analyze the linearly elastic and elasto-plastic response of adhesively bonded tee joints. Joints of this type are finding an increasing number of applications with the increased use of composite materials within advanced aerospace vehicles, and improved tools for the design and analysis of these joints are needed. The linearly elastic results of the code are validated vs. finite element analysis results from the literature under different loading and boundary conditions, and new results are generated to investigate the inelastic behavior of the tee joint. The comparison with the finite element results indicates that HOT-SMAC is an efficient and accurate alternative to the finite element method and has a great deal of potential as an analysis tool for a wide range of bonded joints.

Arnold, Steve M. (Technical Monitor); Bednarcyk, Brett A.; Yarrington, Phillip W.

2004-01-01

276

Laser Joining of Continuous Glass Fiber Composite Pre-forms Huade Tan, Y. Lawrence Yao  

E-print Network

been shown to yield significant improvements in out of plane material properties with some reduction fabrication of thick composite structures. Laser joining is achieved without filler materials to replace is used to investigate the joint strength with respect to joint morphology. Joint strength is found

Yao, Y. Lawrence

277

Joint attention and language evolution  

NASA Astrophysics Data System (ADS)

This study investigates how more advanced joint attentional mechanisms, rather than only shared attention between two agents and an object, can be implemented and how they influence the results of language games played by these agents. We present computer simulations with language games showing that adding constructs that mimic the three stages of joint attention identified in children's early development (checking attention, following attention, and directing attention) substantially increase the performance of agents in these language games. In particular, the rates of improved performance for the individual attentional mechanisms have the same ordering as that of the emergence of these mechanisms in infants' development. These results suggest that language evolution and joint attentional mechanisms have developed in a co-evolutionary way, and that the evolutionary emergence of the individual attentional mechanisms is ordered just like their developmental emergence.

Kwisthout, Johan; Vogt, Paul; Haselager, Pim; Dijkstra, Ton

2008-06-01

278

[Divorce and joint physical custody].  

PubMed

This work first recalls the definition of joint physical custody, as well as the current legal procedure for obtaining it, its practical implementation, the financial implications for parents, and finally some statistics. Some psychological and psychopathological reflections on the impact of divorce on children are then presented before considering the question of joint physically custody with regard to attachment theory and depending on the age of the child (a great caution seems to be required before three years). The article concludes with a brief discussion of parental alienation syndrome. PMID:24630624

Golse, B

2014-04-01

279

Dual and Joint Degrees Dual and Joint Degrees  

E-print Network

Education plus major program overlap · Use existing degree for simpler approval ­ Argues against joint Degrees Conservative: Security and Simplicity · Protect institutional brand integrity ­ Reputation of institutional education ­ Retain control of institution's degree programs · Maintain (relative) simplicity

280

General joint hypermobility and temporomandibular joint derangement in adolescents  

Microsoft Academic Search

Joint mobility was assessed in each member of an epidemiological sample of 96 girls and 97 boys, 17 years old, and graded by means of the hypermobility score of Beighton et al. Twenty two per cent of the girls and 3% of the boys could perform five or more of the nine manoeuvres. The prevalence of symptoms and signs of

L Westling; A Mattiasson

1992-01-01

281

Technique and application for quantifying dynamic shoulder joint kinematics and glenohumeral joint contact patterns  

E-print Network

The shoulder (glenohumeral) joint has the greatest range of motion of all human joints; as a result, it is particularly vulnerable to dislocation and injury. The ability to accurately measure dynamic in-vivo joint kinematics ...

Massimini, Daniel Frank

2014-01-01

282

FRF based joint dynamics modeling and identification  

NASA Astrophysics Data System (ADS)

Complex structures, such as machine tools, are comprised of several substructures connected to each other through joints to form the assembled structures. Joints can have significant contributions on the behavior of the overall assembly and ignoring joint effects in the design stage may result in considerable deviations from the actual dynamic behavior. The identification of joint dynamics enables us to accurately predict overall assembled dynamics by mathematically combining substructure dynamics through the equilibrium and compatibility conditions at the joint. The essence of joint identification is the determination of the difference between the measured overall dynamics and the rigidly coupled substructure dynamics. In this study, we investigate the inverse receptance coupling (IRC) method and the point-mass joint model, which considers the joint as lumped mass, damping and stiffness elements. The dynamic properties of the joint are investigated using both methods through a finite element (FE) simulation and experimental tests. `100

Mehrpouya, Majid; Graham, Eldon; Park, Simon S.

2013-08-01

283

Analysis of selected compression splice joint locations in a graphite-epoxy transport wing stub box  

NASA Technical Reports Server (NTRS)

Three critical compression splice joint locations in a stitched graphite-epoxy transport wing stub box have been analyzed to determine their expected structural performance. The wing box is representative of a section of a commercial transport wing box and was designed and constructed by McDonnell Douglas Aerospace Company as part of the NASA Advanced Composites Technology (ACT) program. The results of the finite element analyses of the splice joints are presented. The analysis results indicate that failure will not occur in the splice joint regions for loads less than the Design Ultimate Load of the wing box.

Jegley, Dawn C.

1995-01-01

284

Reactive Brazing of Carbon-Carbon Composites to Titanium  

NASA Technical Reports Server (NTRS)

The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSil. The joint microstructures were examined using optical microscopy, and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint and possible metallurgical bond formation via interdiffusion, which led to good wetting and spreading.

Shpargel, Tarah; Singh, M.; Morscher, Gregory; Asthana, Rajiv

2004-01-01

285

Active Metal Brazing of Carbon-Carbon Composites to Titanium  

NASA Technical Reports Server (NTRS)

The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSil. The joint microstructures were examined using optical microscopy, and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint which led to good wetting, spreading, and metallurgical bond formation via interdiffusion.

Singh, M.; Shpargel, T. P.; Morscher, G.; Asthana, R.

2004-01-01

286

The temporal relationship between joints and faults  

NASA Astrophysics Data System (ADS)

Examples are presented of three temporal relationships between joints and faults: joints that pre-date faults; joints that are precursors to, or synchronous with, faults; and joints that post-date faults. Emphasis is placed on strike-slip faults in carbonate beds, but other examples are used. General rules are given for identifying the three temporal relationships between joints and faults. Joints that formed before faults can be dilated, sheared or affected by pressure solution during faulting, depending on their orientation in relation to the applied stress system. Faulted joints can preserve some original geometry of a joint pattern, with pinnate joints or veins commonly developing where faulted joints interact. Joints formed synchronously with faults reflect the same stress system that caused the faulting, and tend to increase in frequency toward faults. In contrast, joints that pre- or post-date faults tend not to increase in frequency towards the fault. Joints that post-date a fault may cut across or abut the fault and fault-related veins, without being displaced by the fault. They may also lack dilation near the fault, even if the fault has associated veins. Joints formed either syn- or post-faulting may curve into the fault, indicating stress perturbation around the fault. Different joint patterns may exist across the fault because of mechanical variations. Geometric features may therefore be used in the field to identify the temporal relationships between faults and joints, especially where early joints affect or control fault development, or where the distribution of late joints are influenced by faults.

Peacock, D. C. P.

2001-02-01

287

Flexible joints for thrust vector control  

NASA Technical Reports Server (NTRS)

Flexible joints have been used to achieve thrust vector control over a wide range of sizes of nozzles and have been demonstrated successfully in bench tests and static firings, and are operational on two motors. From these many joints the problems of flexible joints have been defined as establishment of the movable nozzle envelope, definition of the actuation power requirements, definition of the mechanical properties of joint materials, adhesive bonding, test methods, and quality control. These data and problem solutions are contained in a large number of reports. Data relating to joint configuration, design requirements, materials selection, joint design, structural analysis, manufacture, and testing are summarized.

Woodberry, R. F. H.

1975-01-01

288

The Rationale for Joint Mobilization.  

ERIC Educational Resources Information Center

This paper presents an overview of the functions of connective tissue and the mechanisms of joint injury and contracture formation in relation to therapeutic exercise. The components of connective tissue operation are explained, including fibroblasts, macrophages, plasma cells, and collagen. An examination of the histology of connective tissue as…

Burkhardt, Sandy

289

Solders in Real Electronic Joints  

NASA Astrophysics Data System (ADS)

Undercooling and recalescence were studied using the differential scanning calorimetry (DSC) method on real electronic systems. Two solder pastes, Sn62.5Pb36.5Ag1 and Sn96.5Ag3Cu0.5, were used for preparation of electronic joints. Various combinations of these solders and soldering pads with different surface finishes such as Cu, Cu-Ni-Au, Cu-Sn, and Cu-Sn99Cu1 were used. During melting of both pastes, the Sn and Sn99Cu1 surface finishes immediately dissolved in the solder and the Cu surface coating was exposed to the melt. Therefore, practically the same undercooling was found for the Cu, Cu-Sn, and Cu-Sn99Cu1 coatings. The lowest undercooling was found for the Cu-Ni-Au surface finish for both solder pastes. If two separated electronic joints were made on the sample, two separate peaks were found in the DSC signal during solidification. In the sample with only one joint, only one exothermic peak was found. These findings were observed for all paste/surface finish combinations. These data were analyzed, showing that this effect is a consequence of undercooling and recalescence: Latent heat released during solidification of the joint increases the surrounding temperature and influences all the processes taking place.

Rudajevová, A.; Dušek, K.

2014-07-01

290

Sea Lion Skeleton (Gliding Joint)  

NSDL National Science Digital Library

Sea lions are vertebrates with both backbones and ribs. The backbone is a gliding joint, allowing the animal to be flexible, while the ribs main function is to protect it's inner organs. The short tail helps to balance the animal while walking on land.

Ketan Patel (California State University, Fullerton;Student, B)

2007-07-14

291

Fellows Celebrated at Joint Assembly  

NASA Astrophysics Data System (ADS)

The 2007 AGU Fellows were presented at the recent Joint Assembly in Acapulco, Mexico. A formal ceremony was held on 25 May 2007, where President Tim Killeen introduced each Fellow and read a brief statement of the achievements for which each had been selected. The presentations were followed by an honors fiesta at which family members and close colleagues further feted the honorees.

2007-06-01

292

JD MADR Joint Degree Description  

E-print Network

schools has been to seek out or offer additional work in alternative dispute resolution to facilitate. In addition, Law School courses LEX 7016 (Alternative Dispute Resolution) and LEX 7616 (NegotiationJD ­ MADR Joint Degree Description Current trends in the legal profession emphasize alternatives

Berdichevsky, Victor

293

Biofluid lubrication for artificial joints  

Microsoft Academic Search

This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress.

Alice Mae Pendleton

2008-01-01

294

Trends in biological joint resurfacing  

PubMed Central

The treatment of osteochondral lesions and osteoarthritis remains an ongoing clinical challenge in orthopaedics. This review examines the current research in the fields of cartilage regeneration, osteochondral defect treatment, and biological joint resurfacing, and reports on the results of clinical and pre-clinical studies. We also report on novel treatment strategies and discuss their potential promise or pitfalls. Current focus involves the use of a scaffold providing mechanical support with the addition of chondrocytes or mesenchymal stem cells (MSCs), or the use of cell homing to differentiate the organism’s own endogenous cell sources into cartilage. This method is usually performed with scaffolds that have been coated with a chemotactic agent or with structures that support the sustained release of growth factors or other chondroinductive agents. We also discuss unique methods and designs for cell homing and scaffold production, and improvements in biological joint resurfacing. There have been a number of exciting new studies and techniques developed that aim to repair or restore osteochondral lesions and to treat larger defects or the entire articular surface. The concept of a biological total joint replacement appears to have much potential. Cite this article: Bone Joint Res 2013;2:193–9. PMID:24043640

Myers, K. R.; Sgaglione, N. A.; Grande, D. A.

2013-01-01

295

Qualification of adhesives for marine composite-to-steel applications  

Microsoft Academic Search

This paper describes a logical method for the design and certification of adhesively-bonded composite to steel joints for the marine industry. Normally certification is based on documented service at sea. Since these joints have not been previously deployed at sea, no data on their performance exists. Using an integrated combination of mechanical property evaluation and finite element modeling, the load

David R. Speth; Yu Ping Yang; George W. Ritter

2010-01-01

296

Interpersonal and intrapersonal coordinative modes for joint and single task performance.  

PubMed

In recent years, research in the field of social interactions has focused on the exploration of the coordinative structures that substantiate joint task performance. The current project explores whether interpersonal coordination during joint task performance gives rise to a joint coordinative structure across individuals, and whether such coordinative structures are affected by task demands. Principal component analysis (PCA) is used to identify relevant interpersonal and intrapersonal coordinative modes for the single and joint performance of a supra-postural task, which varied along its precision and role demands. In addition, cross-recurrence quantification analysis (CRQA) was combined with PCA in order to quantify the degree and stability of interpersonal coordination across intrapersonal coordinative modes. Results indicate that the composition and number of coordinative modes varied for joint compared to single performance, and that interpersonal coordination across the first coordinative mode increased in degree and stability for joint compared to single performance. Overall, these findings indicate that joint coordinative structures are affected by the nature of the task performed and the constraints it places on joint and single performance. PMID:22406503

Ramenzoni, Verónica C; Riley, Michael A; Shockley, Kevin; Baker, Aimee A

2012-10-01

297

Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning, pages 10061016, Jeju Island, Korea, 1214 July 2012. c 2012 Association for Computational Linguistics  

E-print Network

mentions. The first mechanism is motivated by the compositional nature of Chinese words, whose semanticsProceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing Association for Computational Linguistics Employing Compositional Semantics and Discourse Consistency

298

Side Clamped Beam (SCB) hinge system for delamination tests in beam-type composite specimens  

Microsoft Academic Search

The experimental study of composite delaminations and adhesive joints is usually carried out using beam-type specimens with bonded metallic fixtures to transfer the applied load. However, bonded joints between the composite specimen and the metallic parts might fail, especially under extreme temperature or fatigue test conditions. Moreover, the quality and alignment of the bonding procedure highly depends on the operator

J. Renart; N. Blanco; E. Pajares; J. Costa; S. Lazcano; G. Santacruz

2011-01-01

299

STS payloads mission control study continuation phase A-1. Volume 2-C, task 3: Identification of joint activities and estimation of resources in preparation for joint flight operations  

NASA Technical Reports Server (NTRS)

Payload mission control concepts are developed for real time flight operations of STS. Flight planning, training, simulations, and other flight preparations are included. Payload activities for the preflight phase, activity sequences and organizational allocations, and traffic and experience factors to establish composite man-loading for joint STS payload activities are identified for flight operations from 1980 to 1985.

1976-01-01

300

Joint Bayesian analysis of forensic mixtures.  

PubMed

Evaluation of series of PCR experiments referring to the same evidence is not infrequent in a forensic casework. This situation is met when 'series of results in mixture' (EPGs produced by reiterating PCR experiments over the same DNA mixture extract) have to be interpreted or when 'potentially related traces' (mixtures that can have contributors in common) require a combined interpretation. In these cases, there can be uncertainty on the genotype assignment, since: (a) more than one genotype combination fall under the same peak profile; (b) PCR preferential amplification alters pre-PCR allelic proportions; (c) other, more unpredictable technical problems (dropouts/dropins, etc.) take place. The uncertainty in the genotype assignment is in most cases addressed by empirical methods (selection of just one particular profile; extraction of consensual or composite profiles) that disregard part of the evidence. Genotype assignment should conversely take advantage from a joint Bayesian analysis (JBA) of all STRs peak areas generated at each experiment. This is the typical case of Bayesian analysis in which adoption of object-oriented Bayesian networks (OOBNs) could be highly helpful. Starting from experimentally designed mixtures, we created typical examples of 'series of results in mixture' of 'potentially related traces'. JBA was some administered to the whole peak area evidence, by specifically tailored OOBNs models, which enabled genotype assignment reflecting all the available evidence. Examples of a residual ambiguity in the genotype assignment came to light at assumed genotypes with partially overlapping alleles (for example: AB+AC?ABC). In the 'series of results in mixture', this uncertainty was in part refractory to the joint evaluation. Ambiguity was conversely dissipated at the 'potentially related' trace example, where the ABC allelic scheme at the first trace was interpreted together with other unambiguous combinations (ABCD; AB) at the related trace. We emphasize the need to carry out extensive, blind sensitivity tests specifically addressing the residual ambiguity that arises from overlapping results mixed at various quantitative ratios. PMID:22948016

Pascali, Vince L; Merigioli, Sara

2012-12-01

301

Dynamic Ball & Socket Joint Force Simulator  

E-print Network

The stability of an implant in the bone, one factor in joint replacement survival, is usually tested using biaxial fatigue loading. These loading protocols do not replicate physiological loading conditions. The Dynamic Ball and Socket Joint Force...

Farmer, Ryan Neal

2011-07-26

302

26 - LMFBR Flexible Pipe Joint Development.  

National Technical Information Service (NTIS)

Objective is the qualification of a PLBR-size primary loop flexible piping joint to the ASME Band PVC rules. Progress and activities are reported for: Class 1 flexible joint code approval support, engineering and design, material development, component te...

R. V. Anderson

1978-01-01

303

49 CFR 583.15 - Joint ownership.  

Code of Federal Regulations, 2012 CFR

...Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AUTOMOBILE PARTS CONTENT LABELING § 583.15 Joint ownership. (a) A carline jointly owned and/or produced by more...

2012-10-01

304

Older Person's Guide to Joint Replacement  

MedlinePLUS

... Osteoporosis Related Documents PDF Older Person’s Guide to Joint Replacement Download Join our e-newsletter! Resources Older Person’s Guide to Joint Replacement Tools and Tips Printer-friendly PDF Click here ...

305

United States Bone and Joint Decade  

MedlinePLUS

... President's Corner USBJI Board Staff Global Bone & Joint Decade Contact Us Bylaws Members & Friends Founding Members Participating ... Meeting 2012 Resources Musculoskeletal Summits Bone and Joint Decade Global Network Conference 2009 2011 Musculoskeletal Summit 2013 ...

306

38 CFR 4.45 - The joints.  

...weight-bearing are related considerations. For the purpose of rating disability from arthritis, the shoulder, elbow, wrist, hip, knee, and ankle are considered major joints; multiple involvements of the interphalangeal, metacarpal and carpal joints of the...

2014-07-01

307

Static and fatigue behavior of pin-loaded metal matrix joints. Final report, May-November 1983  

SciTech Connect

Continuously reinforced metal-matrix composites (MMC) have been projected to have the potential to save weight in aerospace structures due to their high strength and stiffness. These structures must somehow be joined together to form larger structures. Historically, the most common and most accepted method of joining structures together is through the use of fasteners with varying amounts of load transfer between them. These types of loadings are very complex and are not well understood even in conventional metals. Some work has been done for the graphite/epoxy composites but very little has been done on continuously reinforced MMC. The objective of this study was to assess the ability of current composite analysis procedures to predict the static behavior of joints made from various unidirectional MMC and to investigate the fatigue behavior of these joints when subjected to constant-amplitude loading. Specific objectives were to determine experimentally the static behavior of double-lapped shear-joint specimens made from three different MMC composites; to analytically predict the static strength of these joints and to experimentally determine whether joints under fatigue loading fail in the same manner as the statistically loaded joints. Three composite materials were chosen for testing: unidirectional B/Al, and SiC/Al and Ti clad unidirectional B4C/Al hybrid. Detailed studies of the materials' behavior were made for both the static and fatigue tests using both destructive and nondestructive evaluation methods.

Grimsley, F.M.

1984-06-01

308

Seismic response of rock joints and jointed rock mass  

SciTech Connect

Long-term stability of emplacement drifts and potential near-field fluid flow resulting from coupled effects are among the concerns for safe disposal of high-level nuclear waste (HLW). A number of factors can induce drift instability or change the near-field flow patterns. Repetitive seismic loads from earthquakes and thermal loads generated by the decay of emplaced waste are two significant factors. One of two key technical uncertainties (KTU) that can potentially pose a high risk of noncompliance with the performance objectives of 10 CFR Part 60 is the prediction of thermal-mechanical (including repetitive seismic load) effects on stability of emplacement drifts and the engineered barrier system. The second KTU of concern is the prediction of thermal-mechanical-hydrological (including repetitive seismic load) effects on the host rock surrounding the engineered barrier system. The Rock Mechanics research project being conducted at the Center for Nuclear Waste Regulatory Analyses (CNWRA) is intended to address certain specific technical issues associated with these two KTUs. This research project has two major components: (i) seismic response of rock joints and a jointed rock mass and (ii) coupled thermal-mechanical-hydrological (TMH) response of a jointed rock mass surrounding the engineered barrier system (EBS). This final report summarizes the research activities concerned with the repetitive seismic load aspect of both these KTUs.

Ghosh, A.; Hsiung, S.M.; Chowdhury, A.H. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1996-06-01

309

of Concrete Pavements Joint PerformanCe  

E-print Network

practitioners under- stand how to optimize concrete pavement joint perfor- mance through the identificationof Concrete Pavements Joint PerformanCe interim Guide for optimum JUNE 2012 #12;#12;Interim Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2

310

Navigating Joint Projects in Telephone Conversations  

ERIC Educational Resources Information Center

Conversation coordinates joint activities and the joint projects that compose them. Participants coordinate (1) vertical transitions on entering and exiting joint projects; and (2) horizontal transitions in continuing within them. Transitions are coordinated using project markers such as uh-huh, yeah, right, and okay. In the authors' proposal,…

Bangerter, Adrian; Clark, Herbert H.; Katz, Anna R.

2004-01-01

311

Sealing of Small Movement Bridge Expansion Joints.  

National Technical Information Service (NTIS)

Sealing of bridge expansion joint systems is important to protect the structural components below the joint from damage due to water, salt, and other roadway debris. A new elastomeric foam-type joint sealant has been developed for sealing small-movement b...

R. B. Malla, M. T. Shaw, M. R. Shrestha, S. Boob

2006-01-01

312

Joints in deployable space truss structures  

NASA Technical Reports Server (NTRS)

Since the response of deployable structural concepts being considered for the Large Deployable Reflector (LDR) backup structure will be dominated by the response of joints, the joint characteristics are significant. An overview is given of the research activities at LaRC on the static behavior of joints for deployable space truss structures. Since a pin-clevis-type joint will be utilized in deployable structures, an experimental research program to characterize the joint parameters which affect stiffness was conducted. An experimental research program was conducted on a second type of joint, referred to as a near-center latch joint. It was used in the center of members on the deployable truss structure for the Control of Flexible Structures (COFS) flight experiment. The test results of the near-center latch joint and the member with the joints indicated that the stiffness of the near-center joint is linear and stiffer than the stiffness of the total member, and that non-linearities in the stiffness characteristics of the total member were due to bending introduced at the ends of the member. The resulting data indicates that stiff linear folding joints can be designed and that bending load paths should be avoided whenever possible. In summary, for deployable structures, special attention to the joint and the structure design is required to minimize the undesirable structural non-linearities.

Rhodes, M.

1988-01-01

313

Joint Invariant Signatures Peter J. Olver  

E-print Network

Joint Invariant Signatures Peter J. Olver School of Mathematics University of Minnesota Minneapolis­Carlo Rota Abstract. A new, algorithmic theory of moving frames is applied to classify joint invariants and joint differential invariants of transformation groups. Equivalence and sym- metry properties

Olver, Peter

314

The frictional properties of joints in rock  

Microsoft Academic Search

Summary The conditions for sliding over artificial joint surfaces have been studied experimentally by cutting rock cylinders at various angles to their axes and studying slip over these surfaces in a triaxial testing apparatus. The types of joint used were: (i) filled with plaster to simulate a soft joint filling, (ii) bare surfaces ground approximately flat, and (iii) natural surfaces

J. C. Jaeger

1959-01-01

315

International Joint Ventures: A Welfare Analysis  

Microsoft Academic Search

We examine the welfare implications of joint venture formation between an MNC and a firm from a less developed country (LDC). For symmetric firms greater the market size, greater is the incentive for joint venture formation. Moreover, joint venture formation is welfare reducing for both high, as well as low levels of demand. However, if the MNC is more efficient

Indrani Roy Chowdhury; Prabla Roy Chowdhury

2002-01-01

316

49 CFR 234.233 - Rail joints.  

Code of Federal Regulations, 2013 CFR

... 4 2013-10-01 2013-10-01 false Rail joints. 234.233 Section 234.233 Transportation...Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located within the limits of a...

2013-10-01

317

49 CFR 234.233 - Rail joints.  

Code of Federal Regulations, 2010 CFR

... 4 2010-10-01 2010-10-01 false Rail joints. 234.233 Section 234.233 Transportation...Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located within the limits of a...

2010-10-01

318

49 CFR 234.233 - Rail joints.  

Code of Federal Regulations, 2011 CFR

... 4 2011-10-01 2011-10-01 false Rail joints. 234.233 Section 234.233 Transportation...Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located within the limits of a...

2011-10-01

319

Corrosion Issues in Solder Joint Design and Service  

SciTech Connect

Corrosion is an important consideration in the design of a solder joint. It must be addressed with respect to the service environment or, as in the case of soldered conduit, as the nature of the medium being transported within piping or tubing. Galvanic-assisted corrosion is of particular concern, given the fact that solder joints are comprised of different metals or alloy compositions that are in contact with one-another. The (thermodynamic) potential for corrosion to take place in a particular environment requires the availability of the galvanic series for those conditions and which includes the metals or alloys in question. However, the corrosion kinetics, which actually determine the rate of material loss under the specified service conditions, are only available through laboratory evaluations or field data that are found in the existing literature or must be obtained by in-house testing.

VIANCO,PAUL T.

1999-11-24

320

Stiffness and strength of suture joints in nature  

NASA Astrophysics Data System (ADS)

Suture joints are remarkable mechanical structures found throughout nature composed of compliant interlocking seams connecting stiffer components. This study investigates the underlying mechanisms and the role of geometry governing the unique mechanical behavior of suture joints. Analytical and numerical composite models are formulated for two suture geometries characterized by a single repeating wavelength (e.g., triangular and rectangular). Stiffness, strength, and local stress distributions are predicted to assess variations in deformation and failure mechanisms. A unique homogeneous stress field is observed throughout both the skeletal and interfacial components of the triangular geometry, thus providing advantages in load transmission, weight, stiffness, strength, energy absorption, and fatigue over the rectangular geometry. The results obtained have relevance to biomimetic design and optimization, suture growth and fusion, and evolutionary phenotype diversity.

Li, Yaning; Ortiz, Christine; Boyce, Mary C.

2011-12-01

321

Foldable self-erecting joint  

NASA Technical Reports Server (NTRS)

The invention relates to a foldable self erecting joint which may be used to deploy the tetratruss frame of the proposed shuttle launched triangular space station. The frame must be folded into the payload bay of the space shuttle orbiter. To deploy the frame the tubes are automatically unfolded and once in position should remain safely. A pair of hinged, tubular members in which the hinging is located at corresponding portions of the members are used. The opposite edge portions are connected by spring-based toggle links which in the unfolded position of the members are nested against one of the members in substantial alignment and over-center for securely locking the joint in the unfolded position.

Pelischek, T. E. (inventor)

1986-01-01

322

Joint stabilizing projects in defense  

SciTech Connect

Joint defensive projects could increase stability and decrease the alert rates of strategic forces. Areas include the defense of the US, Commonwealth of Independent States (CIS), and their allies against third world threats; protection against each other`s accidental or unauthorized launches; and defense against intentional attacks. The most promising area appears to be defining interfaces for the handover of satellite warning and trajectory information, which applies to most phases of theater defense and mutual protection. 19 refs.

Canavan, G.H.; Browne, J.C.; Joseph, R.J.

1992-06-01

323

Joint stabilizing projects in defense  

SciTech Connect

Joint defensive projects could increase stability and decrease the alert rates of strategic forces. Areas include the defense of the US, Commonwealth of Independent States (CIS), and their allies against third world threats; protection against each other's accidental or unauthorized launches; and defense against intentional attacks. The most promising area appears to be defining interfaces for the handover of satellite warning and trajectory information, which applies to most phases of theater defense and mutual protection. 19 refs.

Canavan, G.H.; Browne, J.C.; Joseph, R.J.

1992-06-01

324

Hydraulic fracturing of jointed formations  

SciTech Connect

Measured by volume, North America's largest hydraulic fracturing operations have been conducted at Fenton Hill, New Mexico to create geothermal energy reservoirs. In the largest operation 21,000 m/sup 3/ of water were injected into jointed granitic rock at a depth of 3.5 km. Microearthquakes induced by this injection were measured with geophones placed in five wells drilled into, or very close, to the reservoir, as well as 11 surface seismometers. The large volume of rock over which the microearthquakes were distributed indicates a mechanism of hydraulic stimulation which is at odds with conventional fracturing theory, which predicts failure along a plane which is perpendicular to the least compressive earth stress. A coupled rock mechanics/fluid flow model provides much of the explanation. Shear slippage along pre-existing joints in the rock is more easily induced than conventional tensile failure, particularly when the difference between minimum and maximum earth stresses is large and the joints are oriented at angles between 30 and 60 degrees to the principal earth stresses, and a low viscosity fluid like water is injected. Shear slippage results in local redistribution of stresses, which allows a branching, or dendritic, stimulation pattern to evolve, in agreement with the patterns of microearthquake locations. These results are qualitatively similar to the controversial process known as ''Kiel'' fracturing, in which sequential injections and shut-ins are repeated to create dendritic fractures for enhanced oil and gas recovery. However, we believe that the explanation is shear slippage of pre-existing joints and stress redistribution, not proppant bridging and fluid blocking as suggested by Kiel. 15 refs., 10 figs.

Murphy, H.D.; Fehler, M.C.

1986-01-01

325

The Joint Damping Experiment (JDX)  

NASA Technical Reports Server (NTRS)

The Joint Damping Experiment (JDX), flown on the Shuttle STS-69 Mission, is designed to measure the influence of gravity on the structural damping of a high precision three bay truss. Principal objectives are: (1) Measure vibration damping of a small-scale, pinjointed truss to determine how pin gaps give rise to gravity-dependent damping rates; (2) Evaluate the applicability of ground and low-g aircraft tests for predicting on-orbit behavior; and (3) Evaluate the ability of current nonlinear finite element codes to model the dynamic behavior of the truss. Damping of the truss was inferred from 'Twang' tests that involve plucking the truss structure and recording the decay of the oscillations. Results are summarized as follows. (1) Damping, rates can change by a factor of 3 to 8 through changing the truss orientation; (2) The addition of a few pinned joints to a truss structure can increase the damping by a factor as high as 30; (3) Damping is amplitude dependent; (4) As gravity induced preloads become large (truss long axis perpendicular to gravity vector) the damping is similar to non-pinjointed truss; (5) Impacting in joints drives higher modes in structure; (6) The torsion mode disappears if gravity induced preloads are low.

Folkman, Steven L.; Bingham, Jeff G.; Crookston, Jess R.; Dutson, Joseph D.; Ferney, Brook D.; Ferney, Greg D.; Rowsell, Edwin A.

1997-01-01

326

Analysis of NSTX TF Joint Voltage Measurements  

SciTech Connect

This report presents findings of analyses of recorded current and voltage data associated with 72 electrical joints operating at high current and high mechanical stress. The analysis goal was to characterize the mechanical behavior of each joint and thus evaluate its mechanical supports. The joints are part of the toroidal field (TF) magnet system of the National Spherical Torus Experiment (NSTX) pulsed plasma device operating at the Princeton Plasma Physics Laboratory (PPPL). Since there is not sufficient space near the joints for much traditional mechanical instrumentation, small voltage probes were installed on each joint and their voltage monitoring waveforms have been recorded on sampling digitizers during each NSTX ''shot''.

Woolley R

2005-10-07

327

Ultrasonic Probing Of Complexly Shaped Joints  

NASA Technical Reports Server (NTRS)

Technique developed involves use of ultrasonics to inspect first bond surfaces of solid-rocket-motor joints. By fitting pieces of insulating materials to mate exactly with complicated shapes of affected parts of insulation, complicated shapes redefined into simpler ones probed more easily. When technique used to insonify from insulation side, one readily detects difference between disbond and good bond. Same technique applied to field tang joints, field clevis joints, and aft-dome-to-fixed-nozzle-housing attachment points. Although developed for inspecting joints in solid rocket motors, also applicable to nondestructive evaluation of other complicated joints.

Madaras, Eric I.

1993-01-01

328

Re-Creation of Historical Chrysotile-Containing Joint Compounds  

PubMed Central

Chrysotile-containing joint compound was commonly used in construction of residential and commercial buildings through the mid 1970s; however, these products have not been manufactured in the United States for more than 30 years. Little is known about actual human exposures to chrysotile fibers that may have resulted from use of chrysotile-containing joint compounds, because few exposure and no health-effects studies have been conducted specifically with these products. Because limited amounts of historical joint compounds are available (and the stability or representativeness of aged products is suspect), it is currently impossible to conduct meaningful studies to better understand the nature and magnitude of potential exposures to chrysotile that may have been associated with historical use of these products. Therefore, to support specific exposure and toxicology research activities, two types of chrysotile-containing joint compounds were produced according to original formulations from the late 1960s. To the extent possible, ingredients were the same as those used originally, with many obtained from the original suppliers. The chrysotile used historically in these products was primarily Grade 7RF9 from the Philip Carey mine. Because this mine is closed, a suitable alternate was identified by comparing the sizes and mineral composition of asbestos structures in a sample of what has been represented to be historical joint compound (all of which were chrysotile) to those in samples of three currently commercially available Grade 7 chrysotile products. The re-created materials generally conformed to original product specifications (e.g. viscosity, workability, crack resistance), indicating that these materials are sufficiently representative of the original products to support research activities. PMID:18788019

Brorby, G. P.; Sheehan, P. J.; Berman, D. W.; Greene, J. F.; Holm, S. E.

2008-01-01

329

Composite Load Model Evaluation  

SciTech Connect

The WECC load modeling task force has dedicated its effort in the past few years to develop a composite load model that can represent behaviors of different end-user components. The modeling structure of the composite load model is recommended by the WECC load modeling task force. GE Energy has implemented this composite load model with a new function CMPLDW in its power system simulation software package, PSLF. For the last several years, Bonneville Power Administration (BPA) has taken the lead and collaborated with GE Energy to develop the new composite load model. Pacific Northwest National Laboratory (PNNL) and BPA joint force and conducted the evaluation of the CMPLDW and test its parameter settings to make sure that: • the model initializes properly, • all the parameter settings are functioning, and • the simulation results are as expected. The PNNL effort focused on testing the CMPLDW in a 4-bus system. An exhaustive testing on each parameter setting has been performed to guarantee each setting works. This report is a summary of the PNNL testing results and conclusions.

Lu, Ning; Qiao, Hong (Amy)

2007-09-30

330

Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design  

NASA Astrophysics Data System (ADS)

In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported.

Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong

2014-11-01

331

Joint source based analysis of multiple brain structures in studying major depressive disorder  

NASA Astrophysics Data System (ADS)

We propose a joint Source-Based Analysis (jSBA) framework to identify brain structural variations in patients with Major Depressive Disorder (MDD). In this framework, features representing position, orientation and size (i.e. pose), shape, and local tissue composition are extracted. Subsequently, simultaneous analysis of these features within a joint analysis method is performed to generate the basis sources that show signi cant di erences between subjects with MDD and those in healthy control. Moreover, in a cross-validation leave- one-out experiment, we use a Fisher Linear Discriminant (FLD) classi er to identify individuals within the MDD group. Results show that we can classify the MDD subjects with an accuracy of 76% solely based on the information gathered from the joint analysis of pose, shape, and tissue composition in multiple brain structures.

Ramezani, Mahdi; Rasoulian, Abtin; Hollenstein, Tom; Harkness, Kate; Johnsrude, Ingrid; Abolmaesumi, Purang

2014-03-01

332

Stabilization of the sacroiliac joint.  

PubMed

Lower back pain and pain involving the area of the posterior iliac spine are extremely common. Degeneration of the sacroiliac joint (SIJ) is one potential cause for lower back pain and pain radiating into the groin or buttocks. Degenerative changes to the lumbar spine and sacroiliac joints are common. A recent study evaluating SIJ abnormalities in a primary low back pain population demonstrated 31.7% of patients demonstrated SI joint abnormalities. (4) As is the case for the evaluation and management of isolated lower back pain, the evaluation, management, and role for surgical intervention in SIJ pain is very controversial. Many patients have degenerative changes of the disc, facet joints, and SIJs. A recent systematic review performed to determine the diagnostic accuracy of tests available to clinicians to identify the disc, facet joint, or SIJ as the source of low back pain concluded that tests do exist that change the probability of the disc or SIJ (but not the facet joint) as the source of low back pain. (3) It was also concluded that the usefulness of these tests in clinical practice, particularly for guiding treatment selection, remains unclear. (3) Although there is general agreement that SIJ pathological changes are a potential cause of pain, there is far less agreement about the optimal management of these conditions. A variety of conditions can cause SIJ dysfunction including degenerative and inflammatory arthritis, trauma, prior lumbosacral fusion, hip arthritis, limb length inequality, infections, and neoplasia. (8) There is increasing evidence that image intensifier-guided single periarticular injection can correctly localize pain to the SIJ but the optimal management strategy remains controversial. Recent publications have compared surgical versus injection treatments and fusion versus denervation procedures. (1 , 8) A systematic review found improvement regardless of the treatment, with most studies reporting over 40% improvement in pain as measured by VAS or NRS scores. (8) It cautioned that one of the studies reported 17.6% of patients experiencing mild/no pain compared with 82.4% experiencing marked/severe pain at 39 months after SIJ fusion procedures. (6 , 8) This systematic review also noted that despite improvements in reported pain, less than half of patients who had work status reported as returning to work. (8) Because of the functional and socioeconomic consequences of chronic lower back pain, numerous surgical treatments to improve this condition have been attempted by spinal surgeons through the years. Arthrodesis of the SIJ is a surgical procedure with a long history dating to the beginnings of spinal surgery. (7) Poor results, high complication rates and the need for additional surgical procedures have generally diminished the enthusiasm for this procedure until recently. (6) A variety of "minimally invasive" procedures have been recently introduced that have rekindled enthusiasm for the surgical management of SIJ pathology. The technique demonstrated in the "Stabilization of the SIJ with SI-Bone" is one of these new techniques. There has been a recent publication detailing the very short term clinical outcomes with this technique that reported encouraging results. (5) In this series of 50 patients, quality of life questionnaires were available for 49 patients preoperatively, 41 patients at 3 months, 40 at 6 months and only 27 at 12 months, complicating the ability to accurately assess true outcomes. Although the focus of this video by Geisler is on the surgical technique, there should have been more information provided on the expected surgical outcomes and potential complications of SIJ fusion. (2) The video only gives minimal information on how to appropriately select patients with potential SIJ pathology for surgical intervention. There are insufficient recommendations on the clinical and radiographic follow-up needed for this procedure. A concern with this implant is whether the porous plasma spray coating on the implant actually results in bone growth across the SIJ

Shaffrey, Christopher I; Smith, Justin S

2013-07-01

333

Jointly with the Faculty of Arts and Humanities FACULTY OF SOCIAL SCIENCE  

E-print Network

1 Jointly with the Faculty of Arts and Humanities FACULTY OF SOCIAL SCIENCE Composition and Rules of Procedure 1. The Faculty of Social Science shall consist of the following Departments and Academic Units Departments to the Faculty of Social Science will require the following steps: (i) application

Lennard, William N.

334

Joint Center for Artificial Photosynthesis  

SciTech Connect

The Joint Center for Artificial Photosynthesis (JCAP) is the nation's largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs. JCAP brings together more than 140 top scientists and researchers from the California Institute of Technology and its lead partner, Berkeley Lab, along with collaborators from the SLAC National Accelerator Laboratory, and the University of California campuses at Irvine and San Diego.

Koval, Carl; Lee, Kenny; Houle, Frances; Lewis, Nate

2013-12-10

335

Joint Center for Artificial Photosynthesis  

ScienceCinema

The Joint Center for Artificial Photosynthesis (JCAP) is the nation's largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs. JCAP brings together more than 140 top scientists and researchers from the California Institute of Technology and its lead partner, Berkeley Lab, along with collaborators from the SLAC National Accelerator Laboratory, and the University of California campuses at Irvine and San Diego.

Koval, Carl; Lee, Kenny; Houle, Frances; Lewis, Nate

2013-12-19

336

Space nuclear system expansion joints  

NASA Technical Reports Server (NTRS)

The engineering, design, and fabrication status of the expansion joint unit (EJU) to be employed in the NaK primary coolant piping loop of the 5-kwe Reactor thermoelectric system are described. Four EJU's are needed in the NaK primary coolant piping loop. The four EJU's which will be identical, utilize bellows as the flexing member, are hermetically sealed, and provide double containment. The bellows are of a nested-formed design, and are to be constructed of 1-ply thickness of 0.010-in. Inconel 718. The EJU's provide a minimum piping load margin of safety of +0.22.

Whitaker, W. D.; Shimazki, T. T.

1973-01-01

337

Fatigue and fracture research in composite materials  

NASA Technical Reports Server (NTRS)

The fatigue, fracture, and impact behavior of composite materials are investigated. Bolted and bonded joints are included. The solutions developed are generic in scope and are useful for a wide variety of structural applications. The analytical tools developed are used to demonstrate the damage tolerance, impact resistance, and useful fatigue life of structural composite components. Standard tests for screening improvements in materials and constituents are developed.

Obrien, T. K.

1982-01-01

338

Factors to consider in joint prosthesis systems  

PubMed Central

In joint reconstruction, the techniques and materials that provide the best outcomes for patients have been debated. The main points of controversy relate to the use of hemiarthroplasties versus total joint prostheses with metal-on-metal versus metal-on-polyethylene articulations. This article investigates these areas as well as the applicability of the techniques and materials and the complications that can occur. Hypersensitivity to materials used in joint prostheses is relatively common but often unrecognized. Although the discussion applies to all joints, the temporomandibular joint (TMJ) is emphasized. For TMJ reconstruction, metal-on-polyethylene articulation in total joint prostheses provides better treatment outcomes than metal-on-metal articulation. PMID:17252041

Wolford, Larry M.

2006-01-01

339

High strength concrete provides joint protection  

SciTech Connect

This paper reports on a joint fill material applied on the 24-in. pipe used by Iroquois Gas Transmission Project for its 26-mile Long Island Sound crossing which provides effective joint protection. The 3.35-in. joint fill, made of high instant strength concrete, met stringent requirements for both strength and weight coating, and is environmentally clean to protect the sensitive marine ecosystem. The offshore section, from Bridgeport, Conn., to Long Island, was laid by McDermott, Inc. The high instant strength concrete supplied joint strength and protection during the laying operation, and on the barge itself, where pipe joints are most vulnerable to damage. With joint fill density the same as the concrete already on the pipe, the submerged weight was uniform along the entire length of the marine line, for an essentially seamless coating.

Pool, P. (Offshore Joint Services, Houston, TX (US))

1991-12-01

340

Device for measuring hole elongation in a bolted joint  

NASA Technical Reports Server (NTRS)

A device to determine the operable failure mode of mechanically fastened lightweight composite joints by measuring the hole elongation of a bolted joint is disclosed. The double-lap joint test apparatus comprises a stud, a test specimen having a hole, two load transfer plates, and linear displacement measuring instruments. The test specimen is sandwiched between the two load transfer plates and clamped together with the stud. Spacer washers are placed between the test specimen and each load transfer plate to provide a known, controllable area for the determination of clamping forces around the hole of the specimen attributable to bolt torque. The spacer washers also provide a gap for the mounting of reference angles on each side of the test specimen. Under tensile loading, elongation of the hole of the test specimen causes the stud to move away from the reference angles. This displacement is measured by the voltage output of two linear displacement measuring instruments that are attached to the stud and remain in contact with the reference angles throughout the tensile loading. The present invention obviates previous problems in obtaining specimen deformation measurements by monitoring the reference angles to the test specimen and the linear displacement measuring instruments to the stud.

Wichorek, Gregory R. (inventor)

1987-01-01

341

Fiber-optic Raman Spectroscopy of Joint Tissues  

PubMed Central

In this study, we report adaptation of Raman spectroscopy for arthroscopy of joint tissues using a custom-built fiber optic probe. Differentiation of healthy and damaged tissue or examination of subsurface tissue, such as subchondral bone, is a challenge in arthroscopy because visual inspection may not provide sufficient contrast. Discrimination of healthy versus damaged tissue may be improved by incorporating point spectroscopy or hyperspectral imaging into arthroscopy where contrast is based on molecular structure or chemical composition. Articular joint surfaces of knee cadaveric human tissue and tissue phantoms were examined using a custom-designed Raman fiber optic probe. Fiber-optic Raman spectra were compared against reference spectra of cartilage, subchondral bone and cancellous bone collected using Raman microspectroscopy. In fiber-optic Raman spectra of the articular surface, there was an effect of cartilage thickness on recovery of signal from subchondral bone. At sites with intact cartilage, the bone mineralization ratio decreased but there was a minimal effect in the bone mineral chemistry ratios. Tissue phantoms were prepared as experimental models of the osteochondral interface. Raman spectra of tissue phantoms suggested that optical scattering of cartilage has a large effect on the relative cartilage and bone signal. Finite element analysis modeling of light fluence in the osteochondral interface confirmed experimental findings in human cadaveric tissue and tissue phantoms. These first studies demonstrate proof of principle for Raman arthroscopic measurement of joint tissues and provide a basis for future clinical or animal model studies. PMID:21359366

Esmonde-White, Karen A.; Esmonde-White, Francis W.L.; Morris, Michael D.

2011-01-01

342

Brazing of Carbon Carbon Composites to Cu-clad Molybdenum for Thermal Management Applications  

NASA Technical Reports Server (NTRS)

Advanced carbon carbon composites were joined to copper-clad molybdenum (Cu/Mo) using four active metal brazes containing Ti (Cu ABA, Cusin-1 ABA, Ticuni, and Ticusil) for potential use in thermal management applications. The brazed joints were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Knoop microhardness measurements across the joint region. Metallurgically sound C-C/Cu/Mo joints, devoid of interfacial cracks formed in all cases. The joint interfaces were preferentially enriched in Ti, with Cu ABA joints exhibiting the largest interfacial Ti concentrations. The microhardness measurements revealed hardness gradients across the joint region, with a peak hardness of 300-350 KHN in Cusin-1 ABA and Ticusil joints and 200-250 KHN in Cu ABA and Ticuni joints, respectively.

Singh, M.; Asthana, R.; Shpargel, T> P.

2007-01-01

343

Hydraulic-Leak Detector for Hidden Joints  

NASA Technical Reports Server (NTRS)

Slow leakage of fluid made obvious. Indicator consists of wick wrapped at one end around joint to be monitored. Wick absorbs hydraulic fluid leaking from joint and transmits to opposite end, located outside cover plate and visible to inspector. Leakage manifested as discoloration of outside end of wick. Indicator reveals leaks in hidden fittings on hydraulic lines. Fast inspection of joints without disassembly. Used in aerospace, petroleum, chemical, nuclear, and other industries where removing covers for inspection impossible, difficult, or time-consuming.

Anderson, G. E.; Loo, S.

1986-01-01

344

Joint hypermobility and fibromyalgia in schoolchildren  

Microsoft Academic Search

OBJECTIVES--To test the hypothesis that joint hypermobility may play a part in the pathogenesis of pain in fibromyalgia, schoolchildren were examined for the coexistence of joint hypermobility and fibromyalgia. METHODS--The study group consisted of 338 children (179 boys, 159 girls; mean age 11.5 years, range 9-15 years) from one public school in Beer-Sheva, Israel. In the assessment of joint hypermobility,

A Gedalia; M Klein; D Buskila

1993-01-01

345

Hydrogen damage in friction welded copper joints  

Microsoft Academic Search

The occurrence of hydrogen attack in electrolytic copper and in copper deoxidized with phosphorous, during model heating in oil and in friction welded specimens was investigated. Dissimilar-metal joints, i.e. copper\\/TZM (titanium–zirconium–molybdenum based alloy) joints and copper\\/austenitic steel joints, were subjected to microstructural examinations and tensile strength tests.Microcracks near the weld surface, caused by hydrogen attack, were found to occur in

Andrzej Ambroziak

2010-01-01

346

Joint Affinity Propagation for Multiple View Segmentation  

Microsoft Academic Search

A joint se gmentation is a simultaneous segmentation of registered 2D images and 3D points reconstructed from the multiple view images. It is fundamental in structuring the data for subsequent modeling applications. In this paper, we treat this joint segmentation as a weighted graph label- ing problem. First, we construct a 3D graph for the joint 3D and 2D points

Jianxiong Xiao; Jingdong Wang; Ping Tan; Long Quan

2007-01-01

347

Is joint hypermobility important in prepubertal children?  

Microsoft Academic Search

The purpose of this study was to investigate serum prolidase activity and its relationship with collagen metabolism and joint\\u000a hypermobility, and to determine the prevalence and characteristics of joint hypermobility in prepubertal children. Serum prolidase\\u000a activity was measured spectrophotometrically. Joint hypermobility was defined using Beighton criteria. The children underwent\\u000a complete history and physical examination. Serum levels of prolidase were lower

Pelin Yazgan; ?clal Geyikli; Dost Zeyrek; Lutfu Baktiroglu; Mehmet Ali Kurcer

2008-01-01

348

Software Tools for Analysis of Bonded Joints  

NASA Technical Reports Server (NTRS)

Linear and nonlinear springs have been used to model adhesives in bonded joints. This presentation describes two programs which obtain stresses and strains in bonded joints. For a given bonded joint model, these programs read the corresponding NASTRAN input and output files, use the spring forces or deformations to obtain the adhesive stresses or strain fields, sort the stresses and strains in descending order, and generate Mathematica plot files for three dimensional visualization of the stress and strain fields.

Tahmasebi, Farhad; Broduer, Steve (Technical Monitor)

2001-01-01

349

Chronic palmar dislocation of proximal interphalangeal joints.  

PubMed

Seven patients with chronic palmar dislocations of proximal interphalangeal joints are described. The duration of the dislocation ranged from 4 weeks to 19 months. Satisfactory mobility was restored in each patient after operative reduction and reconstruction of the extensor mechanism. Motion of the proximal interphalangeal joint averaged 57.1 degrees and 29.3 degrees at the distal interphalangeal joint. This method of treatment is preferable to an arthrodesis in selected patients. PMID:3958459

Posner, M A; Kapila, D

1986-03-01

350

Salvage of first metatarsophalangeal joint arthroplasty complications.  

PubMed

There are two broad categories of surgical techniques for first metatarsophalangeal joint arthroplasty. Resection arthroplasty is a resection of the base of the proximal phalanx with or without an interposition graft of capsule or adjacent tendon. The second technique involves a partial or complete joint replacement. The primary indication for these procedures is first metatarsophalangeal joint pain caused by arthritic change. The salvage surgical options for failed metatarsophalangeal joint arthoplasty are directed toward decreasing or eliminating the symptoms arising from the complications of these procedures. PMID:12760573

Baumhauer, Judith F; DiGiovanni, Benedict F

2003-03-01

351

Degenerative joint disease in female ballet dancers.  

PubMed

The relationship between long-term ballet dancing and eventual arthrosis of the hip, ankle, subtalar, and first metatarsophalangeal joint was examined in 19 former professional female dancers, aged 50 to 70 years. The dancers were compared with pair-matched controls. All 38 women underwent medical history taking, clinical examination, and roentgenography of the joints studied. The roentgenographs were independently judged by two investigators and grouped according to a modified classification of Hermodsson. We found a statistically significant increase in roentgenologic arthrosis of the ankle, subtalar, and first metatarsophalangeal joints in the ballet group compared with the control group. There was no significant difference regarding degenerative changes of the hip joint. However, subjects in the dance group who had evidence of degenerative changes on roentgenographs had no clinical complaints. There was a statistically significant increase in hallux valgus deformity in the ballet group (P < 0.05). The dancers also showed a statistically significant increase in flexion, external rotation, and abduction of the hip joint, dorsal flexion of the first metatarsophalangeal joint, and inversion and eversion of subtalar joint. But the control group had statistically significant increased plantar flexion of the first metatarsophalangeal joint. The most important cause of the statistically significant increase of arthrosis of the ankle and first metatarsophalangeal joints must be explained by repetitive microtrauma. PMID:7661255

van Dijk, C N; Lim, L S; Poortman, A; Strübbe, E H; Marti, R K

1995-01-01

352

RESIDUAL STRESS EFFECTS IN FRACTURE OF COMPOSITES AND ADHESIVES  

E-print Network

RESIDUAL STRESS EFFECTS IN FRACTURE OF COMPOSITES AND ADHESIVES JOHN A. NAIRN ABSTRACT Because, they inevitably develop residual thermal stresses. When designing composites or adhesive joints, it is important to account for these residual stresses. It is not the magnitude of the residual stresses that matters

Nairn, John A.

353

Composite modelling of interactions between beaches and structures  

Microsoft Academic Search

An overview of Composite Modelling (CM) is presented, as elaborated in the EU\\/HYDRALAB joint research project Composite Modelling of the Interactions Between Beaches and Structures. An introduction and a review of the main literature on CM in the hydraulic community are given. In Section 3, the case studies of CM of the seven partners participating in this project are discussed.

Herman Gerritsen; James Sutherland; Rolf Deigaard; Mutlu Sumer; Conceição J. E. M. Fortes; Joan P. Sierra; Ulrike Schmidtke

2011-01-01

354

Effects of joint capsule tissue on cartilage degradation in an in vitro joint injury model  

E-print Network

Osteoarthritis is a degenerative disease of the whole joint that affects an estimated 20.7 million Americans. Traumatic joint injury causes an increase in risk for the development of osteoarthritis. A previously developed ...

Lin, Stephanie Norris, 1980-

2004-01-01

355

Nano-Material Aspects of Shock Absorption in Bone Joints  

PubMed Central

This theoretical study is based on a nano-technological evaluation of the effect of pressure on the composite bone fine structure. It turned out, that the well known macroscopic mechano-elastic performance of bones in combination with muscles and tendons is just one functional aspect which is critically supported by additional micro- and nano- shock damping technology aimed at minimising local bone material damage within the joints and supporting spongy bone material. The identified mechanisms comprise essentially three phenomena localised within the three–dimensional spongy structure with channels and so called perforated flexible tensulae membranes of different dimensions intersecting and linking them. Kinetic energy of a mechanical shock may be dissipated within the solid-liquid composite bone structure into heat via the generation of quasi-chaotic hydromechanic micro-turbulence. It may generate electro-kinetic energy in terms of electric currents and potentials. And the resulting specific structural and surface electrochemical changes may induce the compressible intra-osseal liquid to build up pressure dependent free chemical energy. Innovative bone joint prostheses will have to consider and to be adapted to the nano-material aspects of shock absorption in the operated bones. PMID:21625375

Tributsch, H; Copf, F; Copf, p; Hindenlang, U; Niethard, F.U; Schneider, R

2010-01-01

356

The Effect of Peel Stress on the Strength of Adhesively Bonded Joints  

SciTech Connect

Composite wind turbine blades are often attached to a metallic structure with an adhesive bond. The objective of this investigation is to determine which parameters affect the durability of these adhesively bonded joints. The composite-to-steel joint considered in this study typically fails when the adhesive debonds from the steel adherend. Previously, this joint was monotonically loaded in either compression or tension. Compressive and tensile axial loads of the same magnitude produce adhesive stresses with very similar magnitudes but opposite signs. (For the joint considered, tensile loads produce compressive peeh stresses in the adhesive at the location where debonding initiates.) The tensile specimens failed at much higher loads, establishing that the sign of the adhesive peel stresses strongly influences the single-cycle strength of these joints. Building on this earlier work, this study demonstrates that the adhesive peel stresses are also critical for fatigue loading. The results of low-cycle (axial) and high- cycle (bending) fatigue tests are presented. To complement the test results, finite element analyses demonstrate the localized nature of the peel stresses that develop in the adhesive. In addition, these analyses are used to investigate some of the causes of these peel stresses.

Guess, T.R.; Metzinger, K.E.

1998-10-14

357

Age-related mobility loss is joint-specific: an analysis from 6,000 Flexitest results.  

PubMed

Although aging is commonly linked to a reduction in joint range of motion, it is unclear if all body joints behave similarly. To address this issue, the main purpose of this study was to compare age-related loss of mobility of seven body joints. A total of 6,000 participants (3,835 men and 2,165 women) aged 5 to 92 years took part in this study. The maximal passive range of motion of 20 movements was evaluated by Flexitest, and each movement was scored from 0 to 4. Composite scores were obtained for each of seven joints and for overall flexibility (Flexindex (FLX)) by adding individual movement scores. Confirming previous findings, FLX systematically decreased with aging (p < .001), with female participants being more flexible for all ages (p < 0.001) and having a more gradual, 0.6% vs. 0.8%/year, age reduction (p < .001). Starting at 30 and 40 years, respectively, for male and female participants, the relative contribution of each composite joint score to FLX dramatically changed. Shoulder contribution to FLX male's score went from 13.9% at 28 years of age to only 5.2% at 85 years of age. In general, proportionally, shoulder and trunk became less flexible, while elbow and knee mobility was preserved to a greater extent. Our findings indicated that age-related loss of mobility is rather joint-specific, which could be related to distinct routine usage patterns of the major body joints along life. PMID:23529505

Medeiros, Hugo Baptista de Oliveira; de Araújo, Denise Sardinha Mendes Soares; de Araújo, Claudio Gil Soares

2013-12-01

358

Pressure-actuated joint system  

NASA Technical Reports Server (NTRS)

A pressure vessel is provided that includes first and second case segments mated with one another. First and second annular rubber layers are disposed inboard of the first and second case segments, respectively. The second annular rubber layer has a slot extending from the radial inner surface across a portion of its thickness to define a main body portion and a flexible portion. The flexible portion has an interfacing surface portion abutting against an interfacing surface portion of the first annular rubber layer to follow movement of the first annular rubber layer during operation of the pressure vessel. The slot receives pressurized gas and establishes a pressure-actuated joint between the interfacing surface portions. At least one of the interfacing surface portions has a plurality of enclosed and sealed recesses formed therein.

McGuire, John R. (Inventor)

2004-01-01

359

Joint Committee on Atomic Energy  

NSDL National Science Digital Library

From 1946 to 1977, the Joint Committee on Atomic Energy (JAEC) was responsible for making "continuing studies of the activities of the Atomic Energy Commission and of problems relating to the development, use, and control of atomic energy." Over three decades, the Committee looked into peacetime uses of atomic energy, international agreements regarding atomic energy, and various mutual defense agreements. The good people at the Stanford University Libraries & Academic Information Resources (SULAIR) have created this text archive of over 144,000 pages of source materials from the hearings of this committee. Visitors may wish to start with the "About the Collection" area, as it provides a bit more information on the scope of the materials here. After this, visitors are welcome to perform a simple search across the collection, or they may also wish to browse around at their leisure. The site is rounded out by a list of additional sites and resources.

360

JIS - the Joint Information System  

NASA Astrophysics Data System (ADS)

The main aim of JIS (Joint Information System) is to overcome the present lack of detailed knowledge amongst the European Solar Physics community. This lack of knowledge occurs at several levels: groups of researchers, institutions, scientific activities, running programs, resources, new opportunities, observational campaigns etc. JIS will not be data archives -- this is the aim of EGSO, but will provide all information mentioned above collecting all possible data about the institutes and scientists working in the field of solar physics. All European solar physicists will be provided with this information by means of an easy accessible webpage including different inquiry modes (query by country, university, institute, scientist and area of research). Until now such a system did not exist in Europe, but in foreseeable future a user-friendly and logical structured webpage will take on this task.

Hanslmeier, A.; Kienreich, I.; Palle, P.; Sosa, A.

361

Generalized joint hypermobility as a factor in clicking of the temporomandibular joint  

Microsoft Academic Search

Twenty-six patients with clicking or locking of the temporomandibular joint (TMJ) and 28 age- and sex-matched controls were assessed for generalized joint hypermobility by Beighton's method. Function of the masticatory apparatus was measured with Fricton's Craniomandibular Index. The TMJ patients had significantly higher joint mobility scores, but within the patient group there was no correlation between either the dysfunction or

F. A. Khan; J. Pediar

1996-01-01

362

Joint Health & Safety Committee Minutes January 13, 2011 1 JOINT HEALTH & SAFETY COMMITTEE  

E-print Network

Joint Health & Safety Committee Minutes ­ January 13, 2011 1 UNBC JOINT HEALTH & SAFETY COMMITTEE ­ to be confirmed if she accepts. D. HEALTH & SAFETY INCIDENTS REPORT SUMMARY 1. Andrea pointed out that the graph the scheduled meetings. #12;Joint Health & Safety Committee Minutes ­ January 13, 2011 2 Tim asked if we had

Bolch, Tobias

363

Biofluid lubrication for artificial joints  

NASA Astrophysics Data System (ADS)

This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress. The nano-structured biofluids were formed using molecules having well-defined shapes. Understanding nano-structured biofluids leads to new ways of design and synthesis of biofluids that are beneficial for artificial joint performance. Experimental approaches were utilized in the present research. This includes basic analysis of biofluids' property, such as viscosity, fluid shear stress, and shear rate using rheological experiments. Tribological investigation and surface characterization were conducted in order to understand effects of molecular and nanostructures on fluid lubrication. Workpiece surface structure and wear mechanisms were investigated using a scanning electron microscope and a transmission electron microscope. The surface topography was examined using a profilometer. The results demonstrated that with the adding of solid additives, such as crown ether or fullerene acted as rough as the other solids in the 3-body wear systems. In addition, the fullerene supplied low friction and low wear, which designates the lubrication purpose of this particular particle system. This dissertation is constructed of six chapters. The first chapter is an introduction to body fluids, as mentioned earlier. After Chapter II, it examines the motivation and approach of the present research, Chapter III discusses the experimental approaches, including materials, experimental setup, and conditions. In Chapter IV, lubrication properties of various fluids are discussed. The tribological properties and performance nanostructured biofluids are discussed in Chapter V, followed by summary and conclusions in Chapter VI.

Pendleton, Alice Mae

364

Packages and Mitsubishi — International Joint Venture Negotiations  

Microsoft Academic Search

This case covers the negotiations between Packages Limited, Pakistan (Packages) and Mitsubishi Corporation, Japan (Mitsubishi) for the formation of a joint venture to produce Biaxially Oriented Polypropylene (BOPP) film in Pakistan. Packages was established in Pakistan in 1957 as a joint venture between the Wazir Ali Group and AB Auckerland and Rausing of Sweden. Packages manufactured paper and board and

Humaira Arif; Arif Nazir Butt

2006-01-01

365

Application of Hemi-Hip Joint Arthroplasty  

Microsoft Academic Search

Total hip replacement and hip resurfacing arthroplasty are two popular methods for curing the diseases of hip joints to date. While the technology can be considered to be mature, there are still some problems in practice. So, another method, hemi-hip joint arthroplasty, was introduced in this paper. The structure and materials of the prothesis, its experiments in vitro and the

Lan Chen; Mingzhao Chen; Lantian Chen; Ming Hu; Yiwang Bao

2008-01-01

366

Frictional Properties of Artificial Hip Joints  

Microsoft Academic Search

A new generation of hip replacements has been designed incorporating compliant layers to promote fluid film lubrication when the joints are implanted in patients. Tests in the Durham hip function simulator show that the friction in these joints is up to an order of magnitude lower than in currently used prostheses, and because this is due to complete separation of

A Unsworth; M J Pearcy; E F T White; G White

1988-01-01

367

High temperature ceramic/metal joint structure  

DOEpatents

A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

Boyd, Gary L. (Tempe, AZ)

1991-01-01

368

Flexible Protective Shield For Newly Welded Joints  

NASA Technical Reports Server (NTRS)

Simple device promotes defect-free welds in oxidation-prone metals. Welding torch pulls trailing shield behind to provide protective shield of argon gas over hot weld bead. Guide at front of torch holder feeds welding wire to joint. Shield bent or straightened to fit closely against weld joint.

Dyer, Gerald E.

1988-01-01

369

Prognosis of motor development and joint hypermobility  

Microsoft Academic Search

In a study of 59 infants aged 18 months there were 20 with joint hypermobility and delayed motor development, 19 with joint hypermobility and normal motor development, and 20 normal controls. They were reassessed for motor function 3.5 years later at the age of 5 years. Both gross and fine motor performance were significantly delayed in the group of children

E Tirosh; M Jaffe; R Marmur; Y Taub; Z Rosenberg

1991-01-01

370

Design and control of flexure jointed hexapods  

Microsoft Academic Search

By combining static input-output decoupling transformations with hexapod geometric design, the highly coupled dynamics of a flexure jointed hexapod can be decoupled. Several algorithms have been proposed which result in different sets of decoupled inputs and outputs, and which can use a variety of feedback measurements (position, velocity, acceleration, or force in either joint or Cartesian spaces). Three hexapod configurations

John E. McInroy; Jerry C. Hamann

2000-01-01

371

Joint hypermobility leading to osteoarthrosis and chondrocalcinosis  

Microsoft Academic Search

We have reviewed 21 adults referred to rheumatology clinic and considered to have generalised joint hypermobility by the criteria of Carter and Wilkinson (1964), modified by Beighton et al. (1973). They fell into two categories. 5 patients had a raised plasma viscosity (PV) and in each case a definite pathology was found to account for this, superimposed on hypermobile joints.

H A Bird; C R Tribe; P A Bacon

1978-01-01

372

Joint hypermobility in patients with chondromalacia patellae  

Microsoft Academic Search

SUMMARY The relationship between joint mobility and chondromalacia patellae was reported in a prospective study. A total of 115 patients with chondromalacia patellae were compared with 110 healthy individuals without chondromalacia patellae, matched for age and sex, who served as a control group. The degree of joint mobility was scored on a scale of 0-9. The number of individuals with

Z. AL-RAWI; A. H. NESSAN

1997-01-01

373

Navstar Global Positioning System Joint Program Office  

NSDL National Science Digital Library

The Navstar Global Positioning System Joint Program Office site provides links to Navstar and GPS, the Joint Program Office, user equipment, space segment, control segment, CSEL Program Office, acquisition logistics, contacts, resources, GPS program library, configuration management, system engineering, user equipment sustainment, and pseudo random noise requests.

Office, Navstar G.

374

Viscoelastic Analysis of an Adhesive Tubular Joint  

Microsoft Academic Search

The investigations so far available with regard to stress analysis of adhesive joints assume that the adhesive is elastic. In the present analysis the time dependent properties of the adhesive are taken into account by assuming that the adhesive is viscoelastic. The viscoelastic analysis of a tubular joint has been attempted using a prony series fitting for the relaxation modulus

R. S. Alwar; Y. R. Nagaraja

1976-01-01

375

Modeling Joint Synergies to Synthesize Realistic Movements  

E-print Network

for the flexible organization of joints over time when performing a movement. We propose a generic method which joints - shoulder, elbow, wrist - are combined in order to perform a smooth movement. When groups follow here the assumption that synergies can be modeled in a flexible and dynamic fashion in order

Paris-Sud XI, Université de

376

Degenerative Joint Disease in Female Ballet Dancers  

Microsoft Academic Search

The relationship between long-term ballet dancing and eventual arthrosis of the hip, ankle, subtalar, and first metatarsophalangeal joint was examined in 19 former professional female dancers, aged 50 to 70 years. The dancers were compared with pair-matched controls. All 38 women underwent medical history taking, clinical ex amination, and roentgenography of the joints studied. The roentgenographs were independently judged by

C. Niek van Dijk; Liesbeth S. L. Lim; Alina Poortman; Ernst H. Strübbe; Rene K. Marti

1995-01-01

377

A model to simulate the mastication motion at the temporomandibular joint  

NASA Astrophysics Data System (ADS)

The understanding of the mastication system motion is essential to maxillofacial surgeons and dentists in the procedures concerning jaw and teeth corrections. The temporomandibular joint (TMJ), despite its complexity, is one of the most frequently used joints of the human body. The incidence of a great number of injuries in this joint is influenced not only by its regular use during the mastication, but also by the strong forces applied by the muscles and the wide range of movements it is capable to perform. In this work, we propose the development of a jaw simulator capable of reproducing the complete mastication movement. Our jaw simulator is basically composed by three triangle meshes representing the 3D model of the cranium, mandible and teeth; and an anatomically-based joint model conceived to represent the TMJ motion. The polygonal meshes describing the bones and teeth are obtained from CT images and the jaw motion is simulated using the joint model guided by a 3D motion curve obtained from the composition of the standard 2D curves available in the medical literature. The scale, height and width of these original curves are modified to simulate different kind and size of food and to represent the movements" variability depending on patient morphology (teeth, bones, joints and muscles). The evaluation of preliminary results involved the comparison of a dynamic MRI of a healthy person with the respective simulation.

Villamil, Marta B.; Nedel, Luciana P.; Freitas, Carla M. D. S.; Maciel, Anderson

2005-04-01

378

DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES  

E-print Network

DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES PROPERTIES OF JOINT SPECTRA Properties of the Joint Spectra of Sequence of Structures Alexandra A. Soskova Department of Mathematics and Computer of Structures #12;DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES PROPERTIES OF JOINT SPECTRA

Soskova, Alexandra A.

379

Equivalent Continuum Modeling for Shock Wave Propagation in Jointed Media  

Microsoft Academic Search

This study presents discrete and continuum simulations of shock wave propagating through jointed media. The simulations were performed using the Lagrangian hydrocode GEODYN-L with joints treated explicitly using an advanced contact algorithm. They studied both isotropic and anisotropic joint representations. For an isotropically jointed geologic medium, the results show that the properties of the joints can be combined with the

O Vorobiev; T Antoun

2009-01-01

380

Chord, Tie Bar & Crossbracing Joint Detail in Plan; Crossbracing ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Chord, Tie Bar & Crossbracing Joint Detail in Plan; Crossbracing Center Joint Detail in Plan; Chord Joining Detail in Plan & Elevation; Chord, Panel Post, Tie Bar, & Diagonal Brace Joint Detail; Crossbracing Center Joint Detail in Section; Chord, Panel Post, Tie Bar & Horizontal Brace Joint Detail - Narrows Bridge, Spanning Sugar Creek at Old County Road 280 East, Marshall, Parke County, IN

381

Position control of manipulator with passive joints using dynamic coupling  

Microsoft Academic Search

A method of controlling the position of a manipulator composed of active and passive joints is described. The active joints have actuators and position sensors. The passive joints have holding brakes instead of actuators. While the brakes are released, the passive joints are indirectly controlled by the motion of the active joints using the coupling characteristics of manipulator dynamics. While

Hirohiko Arai; Susumu Tachi

1991-01-01

382

Osteoid osteoma in the differential diagnosis of persistent joint pain  

Microsoft Academic Search

We report 20 cases (13 male and 7 female), mean age 21 years) of juxta-articular osteoid osteoma. The distribution of affected joints was as follows: hip joint (7 cases), knee joint (2 cases), ankle joint (2 cases); iliosacral joint (2 cases), lumbar spine (2 cases), carpus (2 cases), shoulder (1 case), second metacarpal (MCP; 1 case) and first metatarsal (MTP;

A. D. Georgoulis; P. N. Soucacos; A. E. Beris; T. A. Xenakis

1995-01-01

383

The effect of sacroiliac joint mobilization on pelvic deformation and the static balance ability of female university students with si joint dysfunction.  

PubMed

[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. PMID:25013280

Son, Jeong-Hyun; Park, Gi Duck; Park, Hoo Sung

2014-06-01

384

Composite Materials  

NASA Technical Reports Server (NTRS)

Composites are lighter and stronger than metals. Aramid fibers like Kevlar and Nomex were developed by DuPont Corporation and can be combined in a honeycomb structure which can give an airplane a light, tough structure. Composites can be molded into many aerodynamic shapes eliminating rivets and fasteners. Langley Research Center has tested composites for both aerospace and non-aerospace applications. They are also used in boat hulls, military shelters, etc.

1985-01-01

385

Shear joint capability versus bolt clearance  

NASA Technical Reports Server (NTRS)

The results of a conservative analysis approach into the determination of shear joint strength capability for typical space-flight hardware as a function of the bolt-hole clearance specified in the design are presented. These joints are comprised of high-strength steel fasteners and abutments constructed of aluminum alloys familiar to the aerospace industry. A general analytical expression was first arrived at which relates bolt-hole clearance to the bolt shear load required to place all joint fasteners into a shear transferring position. Extension of this work allowed the analytical development of joint load capability as a function of the number of fasteners, shear strength of the bolt, bolt-hole clearance, and the desired factor of safety. Analysis results clearly indicate that a typical space-flight hardware joint can withstand significant loading when less than ideal bolt hole clearances are used in the design.

Lee, H. M.

1992-01-01

386

Anatomy and histology of the sacroiliac joints.  

PubMed

The anatomy of joints provides an important basis for understanding the nature and imaging of pathologic lesions and their imaging appearance. This applies especially to the sacroiliac (SI) joints, which play a major role in the diagnosis of spondyloarthritis. They are composed of two different joint portions, a cartilage-covered portion ventrally and a ligamentous portion dorsally, and thus rather complex anatomically. Knowledge of anatomy and the corresponding normal imaging findings are important in the imaging diagnosis of sacroiliitis, especially by MR imaging. A certain distinction between the two joint portions by MR imaging is only obtainable by axial slice orientation. Together with a perpendicular coronal slice orientation, it provides adequate anatomical information and thereby a possibility for detecting the anatomical site of disease-specific characteristics and normal variants simulating disease. This overview describes current knowledge about the normal macroscopic and microscopic anatomy of the SI joints. PMID:24896748

Egund, Niels; Jurik, Anne Grethe

2014-07-01

387

Joint interaction with embedded concretions: joint loading configurations inferred from propagation paths  

NASA Astrophysics Data System (ADS)

The interaction between propagating joints and embedded concretions in a Devonian black shale near Seneca Lake, NY, permits identification of the loading configurations responsible for two joint sets of different ages striking at nearly the same orientation. The earlier set consists of systematic joints cut by later Alleghanian joints of the Appalachian Plateau. The later set consists of non-systematic curving cross joints that abut these same Alleghanian joints. Field evidence shows that concretions functioned as stiff inclusions in a compliant black shale. As a consequence of this elastic contrast, local perturbations in the remote stress field persisted around the concretions during burial, tectonic deformation, and exhumation. These stress perturbations influenced joint propagation paths of both joint sets. Our conclusions about loading configurations are based on finite-element modeling of the effect of the local stress perturbation on concretion-modified joint propagation. Modeling shows that the local stress perturbation from a thermoelastic loading was responsible for deflecting cross joints away from concretions in a curved propagation path near the concretion. This load configuration also led to arrest of cross joints before they penetrated the shale-concretion interface. At greater distances from the concretion, the propagation path of cross joints was controlled by the contemporary tectonic stress field. The interface between concretions and the surrounding shale was strongly bonded, as indicated by the crossing of the interface by some of the systematic ENE joints. Higher compressive stress levels within the concretions relative to the shale suppressed joint development in the concretion, causing the arrest of those joints once they had driven across the interface and a short distance into the concretion. Numerical modeling shows that interface penetration by the systematic ENE joints is consistent with a fluid load, the same loading configuration postulated for the subsequent Alleghanian joints. The traces of the systematic ENE joints align on opposite sides of concretions, rather than curving toward the concretion as predicted by two-dimensional models of the fluid load. Co-planar traces are indicative of large, planar joints propagating in-plane around the concretion, making it energetically inefficient for the crack front to curve as it enters the local stress perturbation near the concretion. A fluid load for the systematic ENE joints came from high pore pressure during the pre-Alleghanian stages of burial of the Devonian Catskill delta complex.

McConaughy, David T.; Engelder, Terry

1999-11-01

388

Energetic composites  

DOEpatents

A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application. 3 figures.

Danen, W.C.; Martin, J.A.

1993-11-30

389

Energetic composites  

DOEpatents

A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

Danen, Wayne C. (Los Alamos, NM); Martin, Joe A. (Espanola, NM)

1993-01-01

390

Electronic hidden solder joint geometry characterization  

NASA Astrophysics Data System (ADS)

To reduce the size of electronic equipment, multi-layer printed circuit board structures have become popular in recent years. As a result, the inspection of hidden solder joints between layers of boards has become increasingly difficult. Xray machines have been used for ball grid array (BGA) and hidden solder joint inspection; however, the equipment is costly and the inspection process is time consuming. In this paper, we investigate an active thermography approach to probing solder joint geometry. A set of boards having the same number of solder joints and amount of solder paste (0.061 g) was fabricated. Each solder joint had a different geometry. A semi-automated system was built to heat and then transfer each board to a chamber where an infrared camera was used to scan the board as it was cooling down. Two-thirds of the data set was used for model development and one-third was used for model evaluation. Both artificial neural network (ANN) and binary logistic regression models were constructed. Results suggest that solder joints with more surface area cool much faster than those with less surface area. In addition, both modeling approaches are consistent in predicting solder geometry; ANN had 85% accuracy and the regression model had 80%. This approach can potentially be used to test for cold solder joints prior to BGA assembly, since cold solder joints may have air gaps between the joint and the board and air is a poor heat conductor. Therefore, a cold solder joint may have a slower cooling rate than a normal one.

Hsieh, Sheng-Jen

2009-05-01

391

An Atypical Molecular Profile for Joint Development in the Avian Costal Joint  

PubMed Central

Development of synovial joints involves generation of cartilaginous anlagen, formation of interzones between cartilage anlagen, and cavitation of interzones to produce fluid filled cavities. Interzone development is not fully understood, but interzones are thought to develop from skeletogenic cells that are inhibited from further chondrogenic development by a cascade of gene expression including Wnt and Bmp family members. We examined the development of the rarely studied avian costal joint to better understand mechanisms of joint development. The costal joint is found within ribs, is morphologically similar to the metatarsophalangeal joint, and undergoes cavitation in a similar manner. In contrast to other interzones, Wnt14/9a, Gdf5, Chordin, Barx1, and Bapx1 are absent from the costal joint interzone, consistent with the absence of active ?-catenin and phosphorylated Smad 1/5/8. However Autotaxin and Noggin are expressed. The molecular profile of the costal joint suggests there are alternative mechanisms of interzone development. PMID:20730871

Winslow, B. B.; Burke, A.C.

2010-01-01

392

Association of Generalized Joint Hypermobility With a History of Glenohumeral Joint Instability  

PubMed Central

Abstract Context: Little is known about the relationship among sex, generalized joint hypermobility, and glenohumeral joint instability. Objective: To examine the relationship among sex, generalized joint hypermobility scores, and a history of glenohumeral joint instability within a young, physically active cohort and to describe the incidence of generalized joint hypermobility within this population. Design: Cross-sectional cohort study. Setting: United States Military Academy at West Point, New York. Patients or Other Participants: Of the 1311 members of the entering freshman class of 2010, 1050 (80%) agreed to participate. Main Outcome Measure(s): Generalized joint hypermobility was assessed using the Beighton Scale. A history of glenohumeral joint instability was identified via a baseline questionnaire. Results: Most participants (78%) had no signs of generalized joint hypermobility. Only 11 volunteers (1.5%) had Beighton Scale scores of 4 or greater. Logistic regression analysis revealed a relationship between generalized joint hypermobility and a history of glenohumeral joint instability (P ?=? .023). When sex and race were controlled, those with a total Beighton Scale score of ?2 were nearly 2.5 times as likely (odds ratio ?=? 2.48, 95% confidence interval ?=? 1.19, 5.20, P ?=? .016) to have reported a history of glenohumeral joint instability. A relationship was observed between sex and nearly all individual Beighton Scale items. Although women had higher total Beighton Scale scores than men, sex (P ?=? .658) and race (P ?=? .410) were not related to a history of glenohumeral joint instability when other variables in the model were controlled. Conclusions: In these participants, generalized joint hypermobility and a history of glenohumeral joint instability were associated. PMID:20446838

Cameron, Kenneth L.; Duffey, Michele L.; DeBerardino, Thomas M.; Stoneman, Paul D.; Jones, Christopher J.; Owens, Brett D.

2010-01-01

393

Electrode compositions  

DOEpatents

An electrode composition for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C.sub.8 -C.sub.15 alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5-4.5 volts.

Block, Jacob (Rockville, MD); Fan, Xiyun (Orange, TX)

1998-01-01

394

Electrode compositions  

DOEpatents

An electrode composition is described for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C{sub 8}-C{sub 15} alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5--4.5 volts.

Block, J.; Fan, X.

1998-10-27

395

Fuel compositions  

SciTech Connect

A phase-stable aqueous gasoline/ethanol fuel composition containing an additional alcohol selected from the group consisting of n-butanol, 2-butanol, iso-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, n-pentanol, and mixtures thereof, as well as a method for producing said fuel composition.

Derderian, E. J.

1985-09-17

396

7 CFR 3406.8 - Joint project proposals.  

Code of Federal Regulations, 2013 CFR

...false Joint project proposals. 3406.8 Section...INSTITUTION CAPACITY BUILDING GRANTS PROGRAM Program Description...3406.8 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2013-01-01

397

7 CFR 3406.8 - Joint project proposals.  

...false Joint project proposals. 3406.8 Section...INSTITUTION CAPACITY BUILDING GRANTS PROGRAM Program Description...3406.8 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2014-01-01

398

7 CFR 3405.7 - Joint project proposals.  

Code of Federal Regulations, 2012 CFR

...false Joint project proposals. 3405.7 Section...HIGHER EDUCATION CHALLENGE GRANTS PROGRAM Program Description...3405.7 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2012-01-01

399

7 CFR 3405.7 - Joint project proposals.  

Code of Federal Regulations, 2011 CFR

...false Joint project proposals. 3405.7 Section...HIGHER EDUCATION CHALLENGE GRANTS PROGRAM Program Description...3405.7 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2011-01-01

400

7 CFR 3405.7 - Joint project proposals.  

...false Joint project proposals. 3405.7 Section...HIGHER EDUCATION CHALLENGE GRANTS PROGRAM Program Description...3405.7 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2014-01-01

401

7 CFR 3406.8 - Joint project proposals.  

Code of Federal Regulations, 2012 CFR

...false Joint project proposals. 3406.8 Section...INSTITUTION CAPACITY BUILDING GRANTS PROGRAM Program Description...3406.8 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2012-01-01

402

7 CFR 3406.8 - Joint project proposals.  

Code of Federal Regulations, 2010 CFR

...false Joint project proposals. 3406.8 Section...INSTITUTION CAPACITY BUILDING GRANTS PROGRAM Program Description...3406.8 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2010-01-01

403

7 CFR 3405.7 - Joint project proposals.  

Code of Federal Regulations, 2013 CFR

...false Joint project proposals. 3405.7 Section...HIGHER EDUCATION CHALLENGE GRANTS PROGRAM Program Description...3405.7 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2013-01-01

404

7 CFR 3406.8 - Joint project proposals.  

Code of Federal Regulations, 2011 CFR

...false Joint project proposals. 3406.8 Section...INSTITUTION CAPACITY BUILDING GRANTS PROGRAM Program Description...3406.8 Joint project proposals. Applicants are encouraged...submit joint project proposals as defined in §...

2011-01-01

405

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Toe joint polymer constrained prosthesis. 888.3720...Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a...

2010-04-01

406

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Toe joint polymer constrained prosthesis. 888.3720...Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a...

2011-04-01

407

21 CFR 888.3780 - Wrist joint polymer constrained prosthesis.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Wrist joint polymer constrained prosthesis. 888.3780...Devices § 888.3780 Wrist joint polymer constrained prosthesis. (a) Identification. A wrist joint polymer constrained prosthesis is a...

2010-04-01

408

21 CFR 872.3940 - Total temporomandibular joint prosthesis.  

Code of Federal Regulations, 2010 CFR

...false Total temporomandibular joint prosthesis. 872.3940 Section 872.3940...3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is intended...

2010-04-01

409

49 CFR 236.59 - Insulated rail joints.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Insulated rail joints. 236.59 Section 236.59 Transportation...Systems Track Circuits § 236.59 Insulated rail joints. Insulated rail joints shall be maintained in condition to...

2010-10-01

410

49 CFR 236.59 - Insulated rail joints.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Insulated rail joints. 236.59 Section 236.59 Transportation...Systems Track Circuits § 236.59 Insulated rail joints. Insulated rail joints shall be maintained in condition to...

2012-10-01

411

49 CFR 234.235 - Insulated rail joints.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Insulated rail joints. 234.235 Section 234.235 Transportation... Maintenance Standards § 234.235 Insulated rail joints. Each insulated rail joint used to separate train detection...

2010-10-01

412

49 CFR 236.59 - Insulated rail joints.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Insulated rail joints. 236.59 Section 236.59 Transportation...Systems Track Circuits § 236.59 Insulated rail joints. Insulated rail joints shall be maintained in condition to...

2011-10-01

413

49 CFR 234.235 - Insulated rail joints.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Insulated rail joints. 234.235 Section 234.235 Transportation... Maintenance Standards § 234.235 Insulated rail joints. Each insulated rail joint used to separate train detection...

2012-10-01

414

49 CFR 234.235 - Insulated rail joints.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Insulated rail joints. 234.235 Section 234.235 Transportation... Maintenance Standards § 234.235 Insulated rail joints. Each insulated rail joint used to separate train detection...

2011-10-01

415

49 CFR 234.235 - Insulated rail joints.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Insulated rail joints. 234.235 Section 234.235 Transportation... Maintenance Standards § 234.235 Insulated rail joints. Each insulated rail joint used to separate train detection...

2013-10-01

416

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Finger joint polymer constrained prosthesis... Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained...

2010-04-01

417

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Finger joint polymer constrained prosthesis... Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained...

2011-04-01

418

ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion—part I: ankle, hip, and spine  

Microsoft Academic Search

The Standardization and Terminology Committee (STC) of the International Society of Biomechanics (ISB) proposes a general reporting standard for joint kinematics based on the Joint Coordinate System (JCS), first proposed by Grood and Suntay for the knee joint in 1983 (J. Biomech. Eng. 105 (1983) 136). There is currently a lack of standard for reporting joint motion in the field

Ge Wu; Sorin Siegler; Paul Allard; Chris Kirtley; Alberto Leardini; Dieter Rosenbaum; Mike Whittle; Darryl D D’Lima; Luca Cristofolini; Hartmut Witte; Oskar Schmid; Ian Stokes

2002-01-01

419

Aksa plans polypropylene joint venture  

SciTech Connect

Turkish acrylic fiber maker Aksa (Yalova), part of the Akkok textile conglomerate, is studying construction of a world-scale polypropylene (PP) plant as part of its diversification plans. The company says it is engaged in discussions with three multinations in the PP business' on the possibility of a joint venture. One of the firms is understood to be Amoco. Aksa is looking at three possible locations for the 100,000 m.t.-150,000 m.t./year plant: Yalova, near Istanbul, where its existing plants are located; Zonguldak, on the Black Sea coast; and within one of the existing complexes or a new site belonging to state-owned Petkim. Aksa has not yet discussed that option with Petkim, which recently received approval to build a $2.5-billion petrochemical complex. The Aksa PP plant would cost about $100 million and would use propylene from world markets. The onstream date depends on Aksa's ability to link up with a foreign partner, but it hopes to complete the unit within three years. Turkey has only one PP plant, a 65,000-m.t./year Petkim unit at Aliaga. The domestic market is currently two to three times that amount and is growing. Petkim also plans a 200,000-m.t./year PP plant as part of its new complex.

Alperowicz, N.

1992-12-02

420

Joint Acoustic Propagation Experiment (JAPE)  

NASA Technical Reports Server (NTRS)

The Joint Acoustic Propagation Experiment (JAPE), performed under the auspices of NATO and the Acoustics Working Group, was conducted at White Sands Missile Range, New Mexico, USA, during the period 11-28 Jul. 1991. JAPE consisted of 220 trials using various acoustic sources including speakers, propane cannon, various types of military vehicles, helicopters, a 155mm howitzer, and static high explosives. Of primary importance to the performance of these tests was the intensive characterization of the atmosphere before and during the trials. Because of the wide range of interests on the part of the participants, JAPE was organized in such a manner to provide a broad cross section of test configurations. These included short and long range propagation from fixed and moving vehicles, terrain masking, and vehicle detection. A number of independent trials were also performed by individual participating agencies using the assets available during JAPE. These tests, while not documented in this report, provided substantial and important data to those groups. Perhaps the most significant feature of JAPE is the establishment of a permanent data base which can be used by not only the participants but by others interested in acoustics. A follow-on test was performed by NASA LaRC during the period 19-29 Aug. 1991 at the same location. These trials consisted of 59 overflights of supersonic aircraft in order to establish the relationship between atmospheric turbulence and the received sonic boom energy at the surface.

Carnes, Benny L.; Olsen, Robert O.; Kennedy, Bruce W.

1993-01-01

421

Temporomandibular joint multidisciplinary team clinic.  

PubMed

Patients with dysfunction of the temporomandibular joint (TMJ) commonly present to oral and maxillofacial departments and are increasingly being managed by a subspecialist group of surgeons. We review the outcomes of patients attending a specialist TMJ multidisciplinary team (MDT) clinic. All patients are simultaneously reviewed by a consultant oral and maxillofacial surgeon, consultant in oral medicine, specialist physiotherapist, and maxillofacial prosthetist, and they can also see a consultant liaison psychiatrist. They are referred from primary, secondary, and tertiary care when medical and surgical treatment in the routine TMJ clinic has failed, and are triaged by the attending maxillofacial surgeon. On discharge they are returned to the care of the referring practitioner. We review the outcomes of patients attending this clinic over a 2-year period and show improvements in pain scores and maximal incisal opening, as well as quality of life outcome measures. All units in the UK with an interest in the management of diseases of the TMJ should consider establishing this type of clinic and should use available resources and expertise to maximise outcomes. PMID:25179688

Ahmed, Nabeela; Poate, Tim; Nacher-Garcia, Cristina; Pugh, Nicola; Cowgill, Helen; Page, Lisa; Matthews, N Shaun

2014-11-01

422

Sealed joint structure for electrochemical device  

DOEpatents

Several members make up a joint in a high-temperature electrochemical device, wherein the various members perform different functions. The joint is useful for joining multiple cells (generally tubular modules) of an electrochemical device to produce a multi-cell segment-in-series stack for a solid oxide fuel cell, for instance. The joint includes sections that bond the joining members to each other; one or more seal sections that provide gas-tightness, and sections providing electrical connection and/or electrical insulation between the various joining members. A suitable joint configuration for an electrochemical device has a metal joint housing, a first porous electrode, a second porous electrode, separated from the first porous electrode by a solid electrolyte, and an insulating member disposed between the metal joint housing and the electrolyte and second electrode. One or more brazes structurally and electrically connects the first electrode to the metal joint housing and forms a gas tight seal between the first electrode and the second electrode.

Tucker, Michael C; Jacobson, Craig P; De Jonghe, Lutgard C; Visco, Steven J

2013-05-21

423

Welding of Duplex Stainless Steel Composite Plate: Influence on Microstructural Development  

Microsoft Academic Search

In the present study, the duplex stainless steel (DSS) composite plate (SAF2205\\/16MnR) was welded by shielded metal arc welding, and the appropriate joint design and welding procedure were carried out. After welding, the mechanical behaviors and microstructure of welded joint were analyzed by using SEM and TEM. Results show that the tensile strength of welded joint satisfied the requirement, and

Shao-Gang Wang; Gui-Ping Dong; Qi-Hui Ma

2009-01-01

424

Inspection of Fusion Joints in Plastic Pipe  

SciTech Connect

The standard method of joining plastic pipe in the field is the butt fusion process. As in any pipeline application, joint quality greatly affects overall operational safety of the system. Currently no simple, reliable, cost-effective method exists for assessing the quality of fusion joints in the field. Visual examination and pressure testing are current nondestructive approaches, which do not provide any assurance about the long-term pipeline performance. This project developed, demonstrated, and validated an in-situ nondestructive inspection method for butt fusion joints in gas distribution plastic pipelines. The inspection system includes a laser-based image-recognition system that automatically generates and interprets digital images of pipe joints and assigns them a pass/fail rating, which eliminates operator bias in evaluating joint quality. An EWI-patented process, the Weld Zone Inspection Method (WZIM) was developed in which local heat is applied to the joint region to relax the residual stresses formed by the original joining operation, which reveals the surface condition of the joint. In cases where the joint is not formed under optimal conditions, and the intermolecular forces between contacting surfaces are not strong enough, the relaxation of macromolecules in the surface layer causes the material to pull back, revealing a fusion line. If the joint is sound, the bond line image does not develop. To establish initial feasibility of the approach, welds were performed under standard and nonstandard conditions. These welds were subjected to the WZIM and two destructive forms of testing: short-term tensile testing and long-term creep rupture testing. There appears to be a direct correlation between the WZIM and the destructive testing results. Although WZIM appears to be more sensitive than destructive testing can verify, the approach appears valid.

Connie Reichert

2005-09-01

425

INSPECTION OF FUSION JOINTS IN PLASTIC PIPE  

SciTech Connect

The standard method of joining plastic pipe in the field is the butt fusion process. As in any pipeline application, joint quality greatly affects overall operational safety of the system. Currently no simple, reliable, cost effective method of assessing the quality of fusion joints in the field exists. Visual examination and pressure testing are current non-destructive approaches, which do not provide any assurance about the long-term pipeline performance. This project will develop, demonstrate, and validate an in-situ non-destructive inspection method for butt fusion joints in gas distribution plastic pipelines. The inspection system will include a laser based image-recognition system that will automatically generate and interpret digital images of pipe joints and assign them a pass/fail rating, which eliminates operator bias in evaluating joint quality. A Weld Zone Inspection Method (WZIM) is being developed in which local heat is applied to the joint region to relax the residual stresses formed by the original joining operation and reveal the surface condition of the joint. In cases where the joint is not formed under optimal conditions, and the intermolecular forces between contacting surfaces are not strong enough, the relaxation of macromolecules in the surface layer causes the material to pull back, revealing a fusion line. If the joint is sound, the bond line image does not develop. To establish initial feasibility of the approach, welds were performed under standard and nonstandard conditions. These welds were subjected to the WZIM and tensile testing. There appears to be a direct correlation between the WZIM and tensile testing results. Although WZIM appears to be more sensitive than tensile testing can verify, the approach appears valid.

Alex Savitski; Connie Reichert; John Coffey

2005-07-13

426

INSPECTION OF FUSION JOINTS IN PLASTIC PIPE  

SciTech Connect

The standard method of joining plastic pipe in the field is the butt fusion process. As in any pipeline application, joint quality greatly affects overall operational safety of the system. Currently no simple, reliable, cost effective method of assessing the quality of fusion joints in the field exists. Visual examination and pressure testing are current non-destructive approaches, which do not provide any assurance about the long-term pipeline performance. This project will develop, demonstrate, and validate an in-situ non-destructive inspection method for butt fusion joints in gas distribution plastic pipelines. The inspection system will include a laser based image-recognition system that will automatically generate and interpret digital images of pipe joints and assign them a pass/fail rating, which eliminates operator bias in evaluating joint quality. A Weld Zone Inspection Method (WZIM) is being developed in which local heat is applied to the joint region to relax the residual stresses formed by the original joining operation and reveal the surface condition of the joint. In cases where the joint is not formed under optimal conditions, and the intermolecular forces between contacting surfaces are not strong enough, the relaxation of macromolecules in the surface layer causes the material to pull back, revealing a fusion line. If the joint is sound, the bond line image does not develop. To establish initial feasibility of the approach, welds were performed under standard and non-standard conditions. These welds were subjected to the WZIM and tensile testing. There appears to be a direct correlation between the WZIM and tensile testing results. Although WZIM appears to be more sensitive than tensile testing can verify, the approach appears valid.

Alex Savitski; Connie Reichert; John Coffey

2004-10-29

427

INSPECTION OF FUSION JOINTS IN PLASTIC PIPE  

SciTech Connect

The standard method of joining plastic pipe in the field is the butt fusion process. As in any pipeline application, joint quality greatly affects overall operational safety of the system. Currently no simple, reliable, cost effective method of assessing the quality of fusion joints in the field exists. Visual examination and pressure testing are current non-destructive approaches, which do not provide any assurance about the long-term pipeline performance. This project will develop, demonstrate, and validate an in-situ non-destructive inspection method for butt fusion joints in gas distribution plastic pipelines. The inspection system will include a laser based image-recognition system that will automatically generate and interpret digital images of pipe joints and assign them a pass/fail rating, which eliminates operator bias in evaluating joint quality. A Weld Zone Inspection Method (WZIM) is being developed in which local heat is applied to the joint region to relax the residual stresses formed by the original joining operation and reveal the surface condition of the joint. In cases where the joint is not formed under optimal conditions, and the intermolecular forces between contacting surfaces are not strong enough, the relaxation of macromolecules in the surface layer causes the material to pull back, revealing a fusion line. If the joint is sound, the bond line image does not develop. To establish initial feasibility of the approach, welds were performed under standard and non-standard conditions. These welds were subjected to the WZIM and tensile testing. There appears to be a direct correlation between the WZIM and tensile testing results. Although WZIM appears to be more sensitive than tensile testing can verify, the approach appears valid.

Alex Savitski; Connie Reichert; John Coffey

2004-07-13

428

Radiology of disorders of the sacroiliac joints  

SciTech Connect

Many disorders can lead to radiological abnormalities of the sacroiliac joints. Some present a characteristic appearance, while others may be diagnosed by analyzing both the appearance and the distribution of findings. Computed tomography provides excellent visualization of the sacroiliac joints and can be helpful in the evaluation of articular disorders as well as pelvic trauma and neoplasms. Radionuclide scanning of bone can also be used to evaluate the sacroiliac joints, particularly if the two sides are compared with the assistance of computer-generated activity counts. This article describes the radiological features of these various disorders that often allow an exact diagnosis to be made.

Resnik, C.S.; Resnick, D.

1985-05-17

429

The locked metacarpophalangeal joint: diagnosis and treatment.  

PubMed

The locked metacarpophalangeal joint of a finger is an unusual condition frequently confused with a "trigger finger." The causes can be classified into degenerative and spontaneous groups. Ten cases are presented. The cause of locking of one patient in the degenerative group was gouty arthritis, a cause not previously reported in the literature. Although surgery is usually necessary, joint mobility was restored in 30% of the cases by distending the joint capsule with an intraarticular injection of a local anesthetic followed by gentle manipulation. In addition to routine x-ray films, arthrotomography was found to be a useful diagnostic technique in determining the cause of locking. PMID:3958458

Posner, M A; Langa, V; Green, S M

1986-03-01

430

Impact of tool wear on joint strength in friction stir spot welding of DP 980 steel  

SciTech Connect

Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Recently a new tool alloy has been developed, using a blend of PCBN and tungsten rhenium (W-Re) in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re, and one with 70% PCBN and 30% W-Re. The sheet material used for all wear testing was 1.4 mm DP 980. Lap shear testing was used to show the relationship between tool wear and joint strength. The Q70 tool provided the best combination of wear resistance and joint strength.

Miles, Michael; Ridges, Chris; Hovanski, Yuri; Peterson, Jeremy; Santella, M. L.; Steel, Russel

2011-09-14

431

Composite Materials  

NASA Technical Reports Server (NTRS)

Langley Research Center researchers invented an advanced polymer, a chemical compound formed by uniting many small molecules to create a complex molecule with different chemical properties. The material is a thermoplastic polyimide that resists solvents. Other polymers of this generic type are soluble in solvents, thus cannot be used where solvents are present. High Technology Services (HTS), Inc. licensed technology and is engaged in development and manufacture of high performance plastics, resins and composite materials. Techimer Materials Division is using technology for composite matrix resins that offer heat resistance and protection from radiation, electrical and chemical degradation. Applications of new polymer include molding resins, adhesives and matrix resins for fiber reinforced composites.

1988-01-01

432

JEC Composites  

NSDL National Science Digital Library

JEC, "a service provider whose vocation is the international promotion of composite materials around the world, and as both an information transmitter and receiver" offers the JEC Composites website. From here, you can learn about what's new in the composites industry across the world and read about recent technological advances in various sectors such as aeronautics, automotive, and construction. For example, have you heard about the material used to make stab-resistant jackets in Japan? Or the material that was used to construct the bike Lance Armstrong used to win the Tour de France? Those in the industry can also get updates on business news, trends, and upcoming conferences.

433

Joint Measurability of Generalized Measurements Implies Classicality  

NASA Astrophysics Data System (ADS)

The fact that not all measurements can be carried out simultaneously is a peculiar feature of quantum mechanics and is responsible for many key phenomena in the theory, such as complementarity or uncertainty relations. For the special case of projective measurements, quantum behavior can be characterized by the commutator but for generalized measurements it is not easy to decide whether two measurements can still be understood in classical terms or whether the already show quantum features. We prove that a set of generalized measurements which does not satisfy the notion of joint measurability is nonclassical, as it can be used for the task of quantum steering. This shows that the notion of joint measurability is, among several definitions, the proper one to characterize quantum behavior. Moreover, the equivalence allows one to derive novel steering inequalities from known results on joint measurability and new criteria for joint measurability from known results on the steerability of states.

Uola, Roope; Moroder, Tobias; Gühne, Otfried

2014-10-01

434

29 CFR 570.115 - Joint applicability.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF LABOR REGULATIONS CHILD LABOR REGULATIONS, ORDERS AND STATEMENTS...Statements of Interpretation of the Child Labor Provisions of the Fair Labor Standards... Joint applicability. The child labor coverage provisions...

2010-07-01

435

21 CFR 26.73 - Joint Committee.  

Code of Federal Regulations, 2012 CFR

...to the application of that agreement not otherwise resolved in the respective Joint Sectoral Committees; (4) Providing a forum for discussion of issues that may arise concerning the implementation of that agreement; (5) Considering ways to...

2012-04-01

436

Instability of the distal radioulnar joint.  

PubMed

The distal radioulnar joint is a complex structure necessary for forearm motion and force transmission across the wrist. Anatomic and biomechanical advances have revealed broad contributions to distal radioulnar joint stability and refined our understanding of the forces acting across it. Instability often co-occurs with other modes of pathology, such as arthrosis or malunion; and appropriate diagnosis and treatment require a comprehensive understanding of all contributing factors. Distal radioulnar joint instability can be broadly categorized as primary, post-traumatic or post-surgical. Treatment strategies include percutaneous, arthroscopic, soft-tissue, osteotomy and arthroplasty techniques. The purpose of this article is to review distal radioulnar joint instability and its management. PMID:24619248

Zimmerman, R M; Jupiter, J B

2014-09-01

437

Dysautonomia in the joint hypermobility syndrome  

Microsoft Academic Search

PurposeExtraarticular manifestations of the joint hypermobility syndrome may include the peripheral nervous system. The purpose of this study was to investigate autonomic function in patients with this syndrome.

Yael Gazit; A. Menahem Nahir; Rodney Grahame; Giris Jacob

2003-01-01

438

Mouse models of osteoarthritis and joint injury  

E-print Network

Nearly 21 million Americans are affected by osteoarthritis, a complex disease characterized by degenerative lesions to the articular cartilage and subchondral bone in the joints. The complexity of the disease makes the use ...

Avedillo, Jose Enrique

2012-01-01

439

Joint measurability of generalized measurements implies classicality.  

PubMed

The fact that not all measurements can be carried out simultaneously is a peculiar feature of quantum mechanics and is responsible for many key phenomena in the theory, such as complementarity or uncertainty relations. For the special case of projective measurements, quantum behavior can be characterized by the commutator but for generalized measurements it is not easy to decide whether two measurements can still be understood in classical terms or whether the already show quantum features. We prove that a set of generalized measurements which does not satisfy the notion of joint measurability is nonclassical, as it can be used for the task of quantum steering. This shows that the notion of joint measurability is, among several definitions, the proper one to characterize quantum behavior. Moreover, the equivalence allows one to derive novel steering inequalities from known results on joint measurability and new criteria for joint measurability from known results on the steerability of states. PMID:25361239

Uola, Roope; Moroder, Tobias; Gühne, Otfried

2014-10-17

440

TEXAS JOINT CENTER FOR AIR QUALITY  

EPA Science Inventory

Status of Subawards   Five of the six subaward projects are complete.  Final reporting from the Texas A&M Galveston project was prevented due to Hurricane Ike in August 2008.  Joint Center staff visited project sites i...

441

Viscoelastic Analysis of Adhesively Bonded Joints.  

National Technical Information Service (NTIS)

An adhesively bonded lap joint is analyzed by assuming that the adherends are elastic and the adhesive is linearly viscoelastic. After formulating the general problem a specific example for two identical adherends bonded through a three parameter viscoela...

F. Delale, F. Erdogan

1980-01-01

442

Joint Refugee Information Clearing Office (JRICO).  

National Technical Information Service (NTIS)

This report provides an historical record of the establishment, procedures, functions, and observations of the Joint Refugee Information Clearing Office (JRICO). Its role was to expedite the Indochinese refugee sponsorship process for members of the Unite...

R. A. Silano

1976-01-01

443

Aging changes in the bones - muscles - joints  

MedlinePLUS

... older women. Bones break more easily, and compression fractures of the vertebrae can cause pain and reduce mobility. Muscle weakness contributes to fatigue, weakness, and reduced activity tolerance. Joint problems are ...

444

Doctrine Logistic Support of Joint Operations.  

National Technical Information Service (NTIS)

To meet our Nations global responsibilities, our ability to move and sustain combat forces virtually anywhere in the world must be maintained. This requires efficiently integrating the unique logistic capabilities of all our Services. Joint doctrine is th...

1995-01-01

445

Sensory response following knee joint damage in rabbits  

PubMed Central

Background Altered sensory information arising from damaged knee joint structures has been hypothesized as a contributing factor to persistent muscle dysfunction following injury. Methods Composite femoral nerve sensory signal was measured in 24 rabbits randomly allocated (8 per group) to receive surgical anterior cruciate ligament (ACL) transection with or without autograft reconstruction or nothing (control). Two-weeks after the intervention composite afferent signals were recorded from the femoral nerve. Side-to-side ratios (surgical side vs contralateral healthy side) for peak femoral nerve afferent composite signal were used for comparison. Results Femoral nerve afferent signal ratios were significantly higher in the ACL-R (2.21?±?0.74) group when compared to the ACL-T (1.28?±?0.61, P?=?0.02) group and Control group (1.31?±?0.78, P?=?0.03). Conclusion The magnitude of sensory information recorded on the femoral nerve is increased following ACL injury and reconstruction surgery, but not after an isolated ACL injury in rabbits. PMID:24766654

2014-01-01

446

Seawater Composition  

NSDL National Science Digital Library

This reference discusses the composition and chemistry of seawater, and how they affect organisms in the sea. Topics include salinity, temperature, density, dissolved gases, dissolved nutrients, and pH.

447

[The artificial joint failure types and analysis].  

PubMed

This paper focused on the joint prosthesis failure event, through survey and investigation in different kinds of case studies, generalized and analyzed the failure reason of joint prosthesis. The failure reason been categorized according to the failure occurring time: short-term, medium-term and long-term, and for each category, the characteristics and root causes are discussed, and the corresponding countermeasures put forward. PMID:22571142

Zhou, Hai; Wang, Liao; Yao, Tianping; Wang, Chengtao

2012-01-01

448

Periprosthetic Joint Infections: Clinical and Bench Research  

PubMed Central

Prosthetic joint infection is a devastating complication with high morbidity and substantial cost. The incidence is low but probably underestimated. Despite a significant basic and clinical research in this field, many questions concerning the definition of prosthetic infection as well the diagnosis and the management of these infections remained unanswered. We review the current literature about the new diagnostic methods, the management and the prevention of prosthetic joint infections. PMID:24288493

Legout, Laurence; Senneville, Eric

2013-01-01

449

Joint Institute for Advancement of Flight Sciences  

NASA Technical Reports Server (NTRS)

Experiments were designed, implemented, and evaluated in the thermal and fluid sciences at the NASA Langley Research Center. This research was conducted cooperatively with NASA employees using, where necessary, equipment and facilities provided by the U.S. Government. The research fell within the scope of the University Agreement between the NASA Langley Research Center and The George Washington University for Joint Research and Education Projects dated June 7, 8, 1994, which continues the Joint Institute for the Advancement of Flight Sciences (JIAFS).

Cutler, Andrew D.

1999-01-01

450

Feature selection for automatic solder joint inspection  

E-print Network

FEATURE SELECTION FOR AUTOMATIC SOLDER JOINT INSPECTION A Thesis CHENG-CHENG LEE Submitted to the Graduate College of Texas AiVM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1987 Major... Subject: Mechanical Engineering FEATURE SELECTION FOR AUTOMATIC SOLDER JOINT INSPECTION A Thesis by CHENG-CHENG LEE Approved as to style and content by: Morris Driels (Chairman of Committee) Norman Gris ld (Member) i(?? Oren Xlasor'i (kfembef...

Lee, Cheng-Cheng

2012-06-07

451

Investigations of copper to stainless steel joints  

Microsoft Academic Search

Tensile and fracture behaviour of two copper alloys i.e. CuAl25 IG0 and CuCrZr and their joints with 316L(N) IG stainless steel produced by hot isostatic pressing (HIP) have been determined in unirradiated and neutron irradiated conditions. The experimental results and the numerical calculations indicate that tensile properties and fracture toughness values of the Cu\\/SS HIP joint specimens are reduced with

S Tähtinen; A Laukkanen; B. N Singh

2001-01-01

452

Optimal joint preventive maintenance and production policies  

Microsoft Academic Search

We study joint preventive maintenance (PM) and production policies for an unreliable production-inventory system in which maintenance\\/repair times are non-negligible and stochastic. A joint policy decides (a) whether or not to perform PM and (b) if PM is not performed, then how much to produce. We consider a discrete-time system, formulating the problem as a Markov decision process (MDP) model.

Xiaodong Yao; Xiaolan Xie; Michael C. Fu; Steven I. Marcus

2005-01-01

453

Joint Coupling for Human Shoulder Complex  

Microsoft Academic Search

In this paper, we present an inverse kinamtics method to determining human shoulder joint motion coupling relationship based\\u000a on experimental data in the literature. The joint coupling relationship is available in the literature, but it is an Euler–angle-based\\u000a relationship. This work focuses on transferring Euler-angle-based coupling equations into a relationship based on the Denavit-Hartenberg\\u000a (DH) method. We use analytical inverse

Jingzhou Yang; Xuemei Feng; Joo H. Kim; Yujiang Xiang; Sudhakar Rajulu

2009-01-01

454

Low-Friction Joint for Robot Fingers  

NASA Technical Reports Server (NTRS)

Mechanical linkage allows adjacent parts to move relative to each other with low friction and with no chatter, slipping, or backlash. Low-friction joint of two surfaces in rolling contact, held in alinement by taut flexible bands. No sliding friction or "stick-slip" motion: Only rolling-contact and bending friction within bands. Proposed linkage intended for finger joints in mechanical hands for robots and manipulators.

Ruoff, C. F.

1985-01-01

455

Superplastic creep of eutectic tinlead solder joints  

Microsoft Academic Search

This paper presents experimental evidence that as-solidified eutectic Pb-Sn solder joints can exhibit superplastic behavior\\u000a in shear creep loading. Stepped load creep tests of as-solidified joints show a change in the stress exponent from a high\\u000a value typical of con-ventional creep at high stress and strain rate to a superplastic value near 2 at lower stress and strain\\u000a rates. In

Z. Mei; D. Grivas; M. C. Shine; J. W. Morris

1990-01-01

456

Is the benign joint hypermobility syndrome benign?  

Microsoft Academic Search

Summary Over a period of two years, joint hypermobility was identified in 95 female and 19 male patients who attended rheumatology and rehabilitation units in Ismailia city. Pauciarticular pains referring to large and medium-sized joints was their most frequent complaint. Clinical diagnosis of carpal and\\/or tarsal tunnel syndromes was made in 45.6% of patients, and various forms of soft tissue

Hassan A. El-Shahaly; Assem K. El-Sherif

1991-01-01

457

CHARACTERIZATION OF DAMPING IN BOLTED LAP JOINTS  

SciTech Connect

The dynamic response of a jointed beam was measured in laboratory experiments. The data were analyzed and the system was mathematically modeled to establish plausible representations of joint damping behavior. Damping is examined in an approximate, local linear framework using log decrement and half power bandwidth approaches. in addition, damping is modeled in a nonlinear framework using a hybrid surface irregularities model that employs a bristles-construct. Experimental and analytical results are presented.

C. MALONEY; D. PEAIRS; ET AL

2000-08-01

458

Minimal formulation of joint motion for biomechanisms  

PubMed Central

Biomechanical systems share many properties with mechanically engineered systems, and researchers have successfully employed mechanical engineering simulation software to investigate the mechanical behavior of diverse biological mechanisms, ranging from biomolecules to human joints. Unlike their man-made counterparts, however, biomechanisms rarely exhibit the simple, uncoupled, pure-axial motion that is engineered into mechanical joints such as sliders, pins, and ball-and-socket joints. Current mechanical modeling software based on internal-coordinate multibody dynamics can formulate engineered joints directly in minimal coordinates, but requires additional coordinates restricted by constraints to model more complex motions. This approach can be inefficient, inaccurate, and difficult for biomechanists to customize. Since complex motion is the rule rather than the exception in biomechanisms, the benefits of minimal coordinate modeling are not fully realized in biomedical research. Here we introduce a practical implementation for empirically-defined internal-coordinate joints, which we call “mobilizers.” A mobilizer encapsulates the observations, measurement frame, and modeling requirements into a hinge specification of the permissible-motion manifold for a minimal set of internal coordinates. Mobilizers support nonlinear mappings that are mathematically equivalent to constraint manifolds but have the advantages of fewer coordinates, no constraints, and exact representation of the biomechanical motion-space—the benefits long enjoyed for internal-coordinate models of mechanical joints. Hinge matrices within the mobilizer are easily specified by user-supplied functions, and provide a direct means of mapping permissible motion derived from empirical data. We present computational results showing substantial performance and accuracy gains for mobilizers versus equivalent joints implemented with constraints. Examples of mobilizers for joints from human biomechanics and molecular dynamics are given. All methods and examples were implemented in Simbody™—an open source multibody-dynamics solver available at https://Simtk.org. PMID:21170173

Seth, Ajay; Sherman, Michael; Eastman, Peter; Delp, Scott

2010-01-01

459

Paediatric musculoskeletal US beyond the hip joint  

Microsoft Academic Search

US is a technique particularly suited to the investigation of musculoskeletal disorders in children and adolescents. This\\u000a review paper describes a range of clinical settings beyond the hip joint where US has a significant role to play, including\\u000a sports injuries, infectious diseases, inflammatory and degenerative conditions, congenital and developmental disorders, acute\\u000a trauma of bone and joints, and peripheral nerve injuries.

Carlo Martinoli; Maura Valle; Clara Malattia; Maria Beatrice Damasio; Alberto Tagliafico

2011-01-01

460

Influences of tendon stiffness, joint stiffness, and electromyographic activity on jump performances using single joint  

Microsoft Academic Search

The present study aimed to examine the influences of tendon stiffness, joint stiffness, and electromyographic activity on\\u000a jump performances consisting of a single-joint movement. Twenty-four men performed three kinds of unilateral maximal jump\\u000a using only the ankle joint (squat jump: SJ; countermovement jump: CMJ; drop jump: DJ) on the sledge apparatus. The relative\\u000a differences in the jump height of CMJ

Keitaro Kubo; Masanori Morimoto; Teruaki Komuro; Naoya Tsunoda; Hiroaki Kanehisa; Tetsuo Fukunaga

2007-01-01

461

Lower limb joint kinetics and ankle joint stiffness in the sprint start push-off  

Microsoft Academic Search

Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain lower limb net joint moments and mechanical powers, and ankle stiffness

Laura Charalambous; Gareth Irwin; Ian N. Bezodis; David Kerwin

2011-01-01

462

Lower limb joint kinetics and ankle joint stiffness in the sprint start push-off  

Microsoft Academic Search

Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain lower limb net joint moments and mechanical powers, and ankle stiffness

Laura Charalambous; Gareth Irwin; Ian N. Bezodis; David Kerwin

2012-01-01

463

Composite Flowers  

NSDL National Science Digital Library

This site, part of Jim Conrad's Backyard Nature Plant web page, discusses this very large family of plants, which includes the sunflower, dandelion, and chrysanthemum. Here you will find information about the composite family's flower structure and the three kinds of composite flowers: ray only, disk only, and ray and disk. There is also a section on how to analyze disk and ray flower structures.

Conrad, Jim

2007-12-17

464

Nonlinear transient analysis of joint dominated structures  

NASA Technical Reports Server (NTRS)

A residual force technique is presented that can perform the transient analyses of large, flexible, and joint dominated structures. The technique permits substantial size reduction in the number of degrees of freedom describing the nonlinear structural models and can account for such nonlinear joint phenomena as free-play and hysteresis. In general, joints can have arbitrary force-state map representations but these are used in the form of residual force maps. One essential feature of the technique is to replace the arbitrary force-state maps describing the nonlinear joints with residual force maps describing the truss links. The main advantage of this replacement is that the incrementally small relative displacements and velocities across a joint are not monitored directly thereby avoiding numerical difficulties. Instead, very small and 'soft' residual forces are defined giving a numerically attractive form for the equations of motion and thereby permitting numerically stable integration algorithms. The technique was successfully applied to the transient analyses of a large 58 bay, 60 meter truss having nonlinear joints. A method to perform link testing is also presented.

Chapman, J. M.; Shaw, F. H.; Russell, W. C.

1987-01-01

465

Subtalar joint stress imaging with tomosynthesis.  

PubMed

The purpose of this study was to perform stress imaging of hindfoot inversion and eversion using tomosynthesis and to assess the subtalar joint range of motion (ROM) of healthy subjects. The subjects were 15 healthy volunteers with a mean age of 29.1 years. Coronal tomosynthesis stress imaging of the subtalar joint was performed in a total of 30 left and right ankles. A Telos stress device was used for the stress load, and the load was 150 N for both inversion and eversion. Tomographic images in which the posterior talocalcaneal joint could be confirmed on the neutral position images were used in measurements. The angle of the intersection formed by a line through the lateral articular facet of the posterior talocalcaneal joint and a line through the surface of the trochlea of the talus was measured. The mean change in the angle of the calcaneus with respect to the talus was 10.3 ± 4.8° with inversion stress and 5.0 ± 3.8° with eversion stress from the neutral position. The result was a clearer depiction of the subtalar joint, and inversion and eversion ROM of the subtalar joint was shown to be about 15° in healthy subjects. Levels of Evidence: Diagnostic, Level IV. PMID:24686905

Teramoto, Atsushi; Watanabe, Kota; Takashima, Hiroyuki; Yamashita, Toshihiko

2014-06-01

466