A depth-of-field limited particle image velocimetry technique applied to oscillatory boundary layer flow over a porous bed

NASA Astrophysics Data System (ADS)

Lara, J. L.; Cowen, E. A.; Sou, I. M.

2002-06-01

Boundary layer flows are ubiquitous in the environment, but their study is often complicated by their thinness, geometric irregularity and boundary porosity. In this paper, we present an approach to making laboratory-based particle image velocimetry (PIV) measurements in these complex flow environments. Clear polycarbonate spheres were used to model a porous and rough bed. The strong curvature of the spheres results in a diffuse volume illuminated region instead of the more traditional finite and thin light sheet illuminated region, resulting in the imaging of both in-focus and significantly out-of-focus particles. Results of a traditional cross-correlation-based PIV-type analysis of these images demonstrate that the mean and turbulent features of an oscillatory boundary layer driven by a free-surface wave over an irregular-shaped porous bed can be robustly measured. Measurements of the mean flow, turbulent intensities, viscous and turbulent stresses are presented and discussed. Velocity spectra have been calculated showing an inertial subrange confirming that the PIV analysis is sufficiently robust to extract turbulence. The presented technique is particularly well suited for the study of highly dynamic free-surface flows that prevent the delivery of the light sheet from above the bed, such as swash flows.

Suction-based grasping tool for removal of regular- and irregular-shaped intraocular foreign bodies.

PubMed

Erlanger, Michael S; Velez-Montoya, Raul; Mackenzie, Douglas; Olson, Jeffrey L

2013-01-01

To describe a suction-based grasping tool for the surgical removal of irregular-shaped and nonferromagnetic intraocular foreign bodies. A surgical tool with suction capabilities, consisting of a stainless steel shaft with a plastic handle and a customizable and interchangeable suction tip, was designed in order to better engage and manipulate irregular-shaped in-traocular foreign bodies of various sizes and physical properties. The maximal suction force and surgical capabilities were assessed in the laboratory and on a cadaveric eye vitrectomy model. The suction force of the water-tight seal between the intraocular foreign body and the suction tip was estimated to be approximately 40 MN. During an open-sky vitrectomy in a porcine model, the device was successful in engaging and firmly securing foreign bodies of different sizes and shapes. The suction-based grasping tool enables removal of irregular-shaped and nonferromagnetic foreign bodies. Copyright 2013, SLACK Incorporated.

Effect of Irregularity in Shape and Boundary of a Macro-Texture Region in Titanium (Postprint)

DTIC Science & Technology

2015-10-15

AFRL-RX-WP-JA-2016-0328 EFFECT OF IRREGULARITY IN SHAPE AND BOUNDARY OF A MACRO-TEXTURE REGION IN TITANIUM (POSTPRINT) James L...2 October 2014 – 15 September 2015 4. TITLE AND SUBTITLE EFFECT OF IRREGULARITY IN SHAPE AND BOUNDARY OF A MACRO-TEXTURE REGION IN TITANIUM ...aerospace grade titanium alloy material are measured to be about the same level as corner trapped shear wave signals. In addition to the abnormally high

Colors and Shapes of the Irregular Planetary Satellites

NASA Astrophysics Data System (ADS)

Graykowski, Ariel; Jewitt, David

2018-04-01

It is widely recognized that the irregular satellites of the giant planets were captured from initially heliocentric orbits. However, the mechanism of capture and the source region from which they were captured both remain unknown. We present an optical color survey of 43 irregular satellites of the outer planets conducted using the LRIS camera on the 10 m telescope at the Keck Observatory in Hawaii. The measured colors are compared to other planetary bodies in search for similarities and differences that may reflect upon the origin of the satellites. We find that ultrared matter (with color index B–R ≥ 1.6), while abundant in the Kuiper Belt and Centaur populations, is depleted from the irregular satellites. We also use repeated determinations of the absolute magnitudes to make a statistical estimate of the average shape of the irregular satellites. The data provide no evidence that the satellites and the main-belt asteroids are differently shaped, consistent with collisions as the major agent shaping both.

Application of machine vision in inspecting stem and shape of fruits

NASA Astrophysics Data System (ADS)

Ying, Yibin; Jing, Hansong; Tao, Yang; Jin, Juanqin; Ibarra, Juan G.; Chen, Zhikuan

2000-12-01

The shape and the condition of stem are important features in classification of Huanghua pears. As the commonly used thinning and erosion-dilation algorithm in judging the presence of the stem is too slow, a new fast algorithm was put forward. Compared with other part of the pear, the stem is obviously thin and long, with the help of various sized templates, the judgment of whether the stem is present was easily made, meanwhile the stem head and the intersection point of stem bottom and pear were labeled. Furthermore, after the slopes of the tangential line of stem head and tangential line of stem bottom were found, the included angle of these two lines was calculated. It was found that the included angle of the broken stem was obviously different from that of the good stem. After the analysis of 53 pictures of pears, the accuracy to judge whether the stem is present is 100% and whether the stem is good reaches 93%. Also, the algorithm is of robustness and can be made invariant to translation and rotation Meanwhile, the method to describe the shape of irregular fruits was studied. Fourier transformation and inverse Fourier transformation pair were adopted to describe the shape of Huanghua pears, and the algorithm for shape identification, which was based on artificial neural network, was developed. The first sixteen harmonic components of the Fourier descriptor were enough to represent the primary shape of pear, and the identification accuracy could reach 90% by applying the Fourier descriptor in combination with artificial neural network.

A comparison of 3 wound measurement techniques: effects of pressure ulcer size and shape.

PubMed

Bilgin, Mehtap; Güneş, Ulkü Yapucu

2013-01-01

The aim of this study was to examine the levels of agreement among 3 techniques used in wound measurement comparing more spherical versus irregularly shaped wounds. The design of this study is evaluative research. Sixty-five consecutive patients with 80 pressure ulcers of various sizes referred from a university hospital in Izmir, Turkey, were evaluated. The 80 pressure ulcers identified on the 65 participants were divided into 2 groups based on pressure ulcer shape and wound surface area. Twenty-four of the 80 ulcers (30%) were characterized as irregularly shaped and greater than 10 cm. Fifty-six were regularly shaped (approximating a circle) and less than 10 cm. Pressure ulcer areas were measured using 3 techniques: measurement with a ruler (wound area was calculated by measuring and multiplying the greatest length by the greatest width perpendicular to the greatest length), wound tracing using graduated acetate paper, and digital planimetry. The level of agreement among the techniques was explored using the intraclass correlation coefficient (ICC). Strong agreement was observed among the techniques when assessing small, more regularly shaped wounds (ICC = 0.95). Modest agreement was achieved when measuring larger, irregularly shaped wounds (ICC = 0.70). Each of these techniques is adequate for measuring surface areas of smaller wounds with an approximately circular shape. Measurement of pressure ulcer area via the ruler method tended to overestimate surface area in larger and more irregularly shaped wounds when compared to acetate and digital planimetry. We recommend digital planimetry or acetate tracing for measurement of larger and more irregularly shaped pressure ulcers in the clinical setting.

3D-shape recognition and size measurement of irregular rough particles using multi-views interferometric out-of-focus imaging.

PubMed

Ouldarbi, L; Talbi, M; Coëtmellec, S; Lebrun, D; Gréhan, G; Perret, G; Brunel, M

2016-11-10

We realize simplified-tomography experiments on irregular rough particles using interferometric out-of-focus imaging. Using two angles of view, we determine the global 3D-shape, the dimensions, and the 3D-orientation of irregular rough particles whose morphologies belong to families such as sticks, plates, and crosses.

Shape functions for velocity interpolation in general hexahedral cells

USGS Publications Warehouse

Naff, R.L.; Russell, T.F.; Wilson, J.D.

2002-01-01

Numerical methods for grids with irregular cells require discrete shape functions to approximate the distribution of quantities across cells. For control-volume mixed finite-element (CVMFE) methods, vector shape functions approximate velocities and vector test functions enforce a discrete form of Darcy's law. In this paper, a new vector shape function is developed for use with irregular, hexahedral cells (trilinear images of cubes). It interpolates velocities and fluxes quadratically, because as shown here, the usual Piola-transformed shape functions, which interpolate linearly, cannot match uniform flow on general hexahedral cells. Truncation-error estimates for the shape function are demonstrated. CVMFE simulations of uniform and non-uniform flow with irregular meshes show first- and second-order convergence of fluxes in the L2 norm in the presence and absence of singularities, respectively.

Smoking-related interstitial fibrosis combined with pulmonary emphysema: computed tomography-pathologic correlative study using lobectomy specimens.

PubMed

Otani, Hideji; Tanaka, Tomonori; Murata, Kiyoshi; Fukuoka, Junya; Nitta, Norihisa; Nagatani, Yukihiro; Sonoda, Akinaga; Takahashi, Masashi

2016-01-01

To evaluate the incidence and pathologic correlation of thin-section computed tomography (TSCT) findings in smoking-related interstitial fibrosis (SRIF) with pulmonary emphysema. Our study included 172 consecutive patients who underwent TSCT and subsequent lobectomy. TSCT findings including clustered cysts with visible walls (CCVW) and ground-glass attenuation with/without reticulation (GGAR) were evaluated and compared in nonsmokers and smokers and among lung locations. TSCT findings, especially CCVW, were also compared with histological findings using lobectomy specimens. The incidence of CCVW and GGAR was significantly higher in smokers than in nonsmokers (34.1% and 40.7%, respectively, vs 2.0% and 12.2%). CCVW and GGAR were frequently found in the lower and peripheral zones. Histologically, CCVW corresponded more often with SRIF with emphysema than usual interstitial pneumonia (UIP, 63.3% vs 30%). CCVW of irregular size and shape were seen in 19 of 20 SRIF with emphysema and in seven of nine UIP-manifested areas with similar round cysts. A less-involved subpleural parenchyma was observed more frequently in SRIF with emphysema. SRIF with emphysema is a more frequent pathological finding than UIP in patients with CCVW on TSCT. The irregular size and shape of CCVW and a less-involved subpleural parenchyma may be a clue suggesting the presence of SRIF with emphysema.

Evaluation of the Gini Coefficient in Spatial Scan Statistics for Detecting Irregularly Shaped Clusters

PubMed Central

Kim, Jiyu; Jung, Inkyung

2017-01-01

Spatial scan statistics with circular or elliptic scanning windows are commonly used for cluster detection in various applications, such as the identification of geographical disease clusters from epidemiological data. It has been pointed out that the method may have difficulty in correctly identifying non-compact, arbitrarily shaped clusters. In this paper, we evaluated the Gini coefficient for detecting irregularly shaped clusters through a simulation study. The Gini coefficient, the use of which in spatial scan statistics was recently proposed, is a criterion measure for optimizing the maximum reported cluster size. Our simulation study results showed that using the Gini coefficient works better than the original spatial scan statistic for identifying irregularly shaped clusters, by reporting an optimized and refined collection of clusters rather than a single larger cluster. We have provided a real data example that seems to support the simulation results. We think that using the Gini coefficient in spatial scan statistics can be helpful for the detection of irregularly shaped clusters. PMID:28129368

The generation and use of numerical shape models for irregular Solar System objects

NASA Technical Reports Server (NTRS)

Simonelli, Damon P.; Thomas, Peter C.; Carcich, Brian T.; Veverka, Joseph

1993-01-01

We describe a procedure that allows the efficient generation of numerical shape models for irregular Solar System objects, where a numerical model is simply a table of evenly spaced body-centered latitudes and longitudes and their associated radii. This modeling technique uses a combination of data from limbs, terminators, and control points, and produces shape models that have some important advantages over analytical shape models. Accurate numerical shape models make it feasible to study irregular objects with a wide range of standard scientific analysis techniques. These applications include the determination of moments of inertia and surface gravity, the mapping of surface locations and structural orientations, photometric measurement and analysis, the reprojection and mosaicking of digital images, and the generation of albedo maps. The capabilities of our modeling procedure are illustrated through the development of an accurate numerical shape model for Phobos and the production of a global, high-resolution, high-pass-filtered digital image mosaic of this Martian moon. Other irregular objects that have been modeled, or are being modeled, include the asteroid Gaspra and the satellites Deimos, Amalthea, Epimetheus, Janus, Hyperion, and Proteus.

Particle morphology influence on mechanical and biocompatibility properties of injection molded Ti alloy powder.

PubMed

Gülsoy, H Özkan; Gülsoy, Nagihan; Calışıcı, Rahmi

2014-01-01

Titanium and Titanium alloys exhibits properties that are excellent for various bio-applications. Metal injection molding is a processing route that offers reduction in costs, with the added advantage of near net-shape components. Different physical properties of Titanium alloy powders, shaped and processed via injection molding can achieve high complexity of part geometry with mechanical and bioactivity properties, similar or superior to wrought material. This study describes that the effect of particle morphology on the microstructural, mechanical and biocompatibility properties of injection molded Ti-6Al-4V (Ti64) alloy powder for biomaterials applications. Ti64 powders irregular and spherical in shape were injection molded with wax based binder. Binder debinding was performed in solvent and thermal method. After debinding the samples were sintered under high vacuum. Metallographic studies were determined to densification and the corresponding microstructural changes. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. The results show that spherical and irregular powder could be sintered to a maximum theoretical density. Maximum tensile strength was obtained for spherical shape powder sintered. The tensile strength of the irregular shape powder sintered at the same temperature was lower due to higher porosity. Finally, mechanical tests show that the irregular shape powder has lower mechanical properties than spherical shape powder. The sintered irregular Ti64 powder exhibited better biocompatibility than sintered spherical Ti64 powder. Results of study showed that sintered spherical and irregular Ti64 powders exhibited high mechanical properties and good biocompatibility properties.

Two new Myxidium species (Myxosporea: Myxidiidae) infecting the gallbladder of African flying fish, Cheilopogon nigricans and Suez fusilier, Caesio suevicus from the Red Sea, Egypt: a morphological and morphometric study.

PubMed

Abdel-Baki, Abdel-Azeem Sh

2009-08-01

Myxidium maamouni sp. n. and Myxidium aydai sp. n. were described from the gallbladder of the African flying fish Cheilopogon nigricans and Suez fusilier Caesio suevicus, respectively. Fishes were collected from the Red Sea at Al-Quseir, Egypt. M. maamouni have irregular to mostly rounded polysporous plasmodia with diameter of 27 microm. Spores were sigmoid or S-shaped and sometimes spindle-shaped in the frontal view with smooth valves. They measured 13.5 x 8.0 x 8.2 microm in size. Their polar capsules were equal pyriform and measured 7.0 x 3.2 microm in size with nine to 12 coils. Spores of M. aydai were spindle-shaped in the frontal view with thin smooth valves. They measured 23.0 x 5.6 x 5.5 microm in size. Their polar capsules were pyriform and measured 7.2 x 3.4 microm in size with eight to nine coils.

Determination of Slake Durability Index (Sdi) Values on Different Shape of Laminated Marl Samples

NASA Astrophysics Data System (ADS)

Ankara, Hüseyin; Çiçek, Fatma; Talha Deniz, İsmail; Uçak, Emre; Yerel Kandemir, Süheyla

2016-10-01

The slake durability index (SDI) test is widely used to determine the disintegration characteristic of the weak and clay-bearing rocks in geo-engineering problems. However, due to the different shapes of sample pieces, such as, irregular shapes displayed mechanical breakages in the slaking process, the SDI test has some limitations that affect the index values. In addition, shape and surface roughness of laminated marl samples have a severe influence on the SDI. In this study, a new sample preparation method called Pasha Method was used to prepare spherical specimens from the laminated marl collected from Seyitomer collar (SLI). Moreover the SDI tests were performed on equal size and weight specimens: three sets with different shapes were used. The three different sets were prepared as the test samples which had sphere shape, parallel to the layers in irregular shape, and vertical to the layers in irregular shape. Index values were determined for the three different sets subjected to the SDI test for 4 cycles. The index values at the end of fourth cycle were found to be 98.43, 98.39 and 97.20 %, respectively. As seen, the index values of the sphere sample set were found to be higher than irregular sample sets.

Earth Observations taken by Expedition 38 Crewmember

NASA Image and Video Library

2014-02-14

ISS038-E-047388 (14 Feb. 2014) --- As the International Space Station passed over the deserts of central Iran, including Kavir, one of the Expedition 38 crew members used a digital camera equipped with a 200mm lens to record this image featuring an unusual pattern of numerous parallel lines and sweeping curves. The lack of soil and vegetation allows the geological structure of the rocks to appear quite clearly. According to geologists, the patterns result from the gentle folding of numerous, thin, light and dark layers of rock. Later erosion by wind and water, say the scientists, cut a flat surface across the folds, not only exposing hundreds of layers but also showing the shapes of the folds. The dark water of a lake (image center) occupies a depression in a more easily eroded, S-shaped layer of rock. The irregular light-toned patch just left of the lake is a sand sheet thin enough to allow the underlying rock layers to be detected. A small river snakes across the bottom of the image. In this desert landscape there are no fields or roads to give a sense of scale. In fact, the image width represents a distance of 65 kilometers.

Uniform irradiation of irregularly shaped cavities for photodynamic therapy.

PubMed

Rem, A I; van Gemert, M J; van der Meulen, F W; Gijsbers, G H; Beek, J F

1997-03-01

It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a cubical box, a sphere, a cylinder and a 'bottle-neck' geometry have been investigated experimentally and the results have been compared with computed light distributions obtained using the 'radiosity method'. A high reflection coefficient of the mould and the best uniform direct irradiance possible on the inside of the mould were found to be important determinants for achieving a uniform light distribution.

Alignment of Irregular Grains by Mechanical Torques

NASA Astrophysics Data System (ADS)

Hoang, Thiem; Cho, Jungyeon; Lazarian, A.

2018-01-01

We study the alignment of irregular dust grains by mechanical torques due to the drift of grains through the ambient gas. We first calculate mechanical alignment torques (MATs) resulting from specular reflection of gas atoms for seven irregular shapes: one shape of mirror symmetry, three highly irregular shapes (HIS), and three weakly irregular shapes (WIS). We find that the grain with mirror symmetry experiences negligible MATs due to its mirror-symmetry geometry. Three HIS can produce strong MATs, which exhibit some generic properties as radiative torques (RATs), while three WIS produce less efficient MATs. We then study grain alignment by MATs for the different angles between the drift velocity and the ambient magnetic field, for paramagnetic and superparamagnetic grains assuming efficient internal relaxation. We find that for HIS grains, MATs can align subsonically drifting grains in the same way as RATs, with low-J and high-J attractors. For supersonic drift, MATs can align grains with low-J and high-J attractors, analogous to RAT alignment by anisotropic radiation. We also show that the joint action of MATs and magnetic torques in grains with iron inclusions can lead to perfect MAT alignment. Our results point out the potential importance of MAT alignment for HIS grains predicted by the analytical model of Lazarian & Hoang, although more theoretical and observational studies are required due to uncertainty in the shape of interstellar grains. We outline astrophysical environments where MAT alignment is potentially important.

Influence of initial stress, irregularity and heterogeneity on Love-type wave propagation in double pre-stressed irregular layers lying over a pre-stressed half-space

NASA Astrophysics Data System (ADS)

Singh, Abhishek Kumar; Das, Amrita; Parween, Zeenat; Chattopadhyay, Amares

2015-10-01

The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half-space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface of uppermost initially stressed heterogeneous layer and intermediate initially stressed isotropic layer. Dispersion equations are obtained in closed form for both cases of irregularities, distinctly. The effect of size and shape of irregularity, horizontal compressive initial stress, horizontal tensile initial stress, heterogeneity of the uppermost layer and width ratio of the layers on phase velocity of Love-type wave are the major highlights of the study. Comparative study has been made to identify the effects of different shapes of irregularity, presence of heterogeneity and initial stresses. Numerical computations have been carried out and depicted by means of graphs for the present study.

A model of Saturn inferred from its measured gravitational field

NASA Astrophysics Data System (ADS)

Kong, Dali; Zhang, Keke; Schubert, Gerald; Anderson, John D.

2018-04-01

We present an interior model of Saturn with an ice-rock core, a metallic region, an outer molecular envelope and a thin transition layer between the metallic and molecular regions. The shape of Saturn’s 1 bar surface is irregular and determined fully self-consistently by the required equilibrium condition. While the ice-rock core is assumed to have a uniform density, three different equations of state are adopted for the metallic, molecular and transition regions. The Saturnian model is constrained by its known mass, its known equatorial and polar radii, and its known zonal gravitational coefficients, J 2n , n = 1, 2, 3. The model produces an ice-rock core with equatorial radius 0.203 R S, where R S is the equatorial radius of Saturn at the 1-bar pressure surface; the core density ρ c = 10388.1 kgm‑3 corresponding to 13.06 Earth masses; and an analytical expression describing the Saturnian irregular shape of the 1-bar pressure level. The model also predicts the values of the higher-order gravitational coefficients, J 8, J 10 and J 12, for the hydrostatic Saturn and suggests that Saturn’s convective dynamo operates in the metallic region approximately defined by 0.2 R S < r e < 0.7 R S, where r e denotes the equatorial radial distance from the Saturnian center of figure.

Smoking-related interstitial fibrosis combined with pulmonary emphysema: computed tomography-pathologic correlative study using lobectomy specimens

PubMed Central

Otani, Hideji; Tanaka, Tomonori; Murata, Kiyoshi; Fukuoka, Junya; Nitta, Norihisa; Nagatani, Yukihiro; Sonoda, Akinaga; Takahashi, Masashi

2016-01-01

Purpose To evaluate the incidence and pathologic correlation of thin-section computed tomography (TSCT) findings in smoking-related interstitial fibrosis (SRIF) with pulmonary emphysema. Patients and methods Our study included 172 consecutive patients who underwent TSCT and subsequent lobectomy. TSCT findings including clustered cysts with visible walls (CCVW) and ground-glass attenuation with/without reticulation (GGAR) were evaluated and compared in nonsmokers and smokers and among lung locations. TSCT findings, especially CCVW, were also compared with histological findings using lobectomy specimens. Results The incidence of CCVW and GGAR was significantly higher in smokers than in nonsmokers (34.1% and 40.7%, respectively, vs 2.0% and 12.2%). CCVW and GGAR were frequently found in the lower and peripheral zones. Histologically, CCVW corresponded more often with SRIF with emphysema than usual interstitial pneumonia (UIP, 63.3% vs 30%). CCVW of irregular size and shape were seen in 19 of 20 SRIF with emphysema and in seven of nine UIP-manifested areas with similar round cysts. A less-involved subpleural parenchyma was observed more frequently in SRIF with emphysema. Conclusion SRIF with emphysema is a more frequent pathological finding than UIP in patients with CCVW on TSCT. The irregular size and shape of CCVW and a less-involved subpleural parenchyma may be a clue suggesting the presence of SRIF with emphysema. PMID:27445472

"To be or not to be in a good shape": diagnostic and clinical value of nuclear shape irregularities in thyroid and breast cancer.

PubMed

Bussolati, Gianni; Maletta, Francesca; Asioli, Sofia; Annaratone, Laura; Sapino, Anna; Marchiò, Caterina

2014-01-01

Variation in both nuclear shape and size ("pleomorphism"), coupled with changes in chromatin amount and distribution, remains the basic criteria for microscopy in a cytologic diagnosis of cancer. The biological determinants of nuclear shape irregularities are not clarified, so, rather than on the genesis of nuclear irregularities, we here focus our attention on a descriptive analysis of nuclear pleomorphism. We keep in mind that evaluation of nuclear shape as currently practiced in routine preparations is improper because it is indirectly based on the distribution of DNA as revealed by the affinity for basic dyes. Therefore, over the last years we have been using as criteria morphological features of nuclei of thyroid and breast carcinomas as determined by immunofluorescence, in situ hybridization, and 3D reconstruction. We have translated this approach to routine diagnostic pathology on tissue sections by employing immunoperoxidase staining for emerin. Direct detection of nuclear envelope irregularities by tagging nuclear membrane proteins such as lamin B and emerin has resulted in a more objective definition of the shape of the nucleus. In this review we discuss in detail methodological issues as well as diagnostic and prognostic implications provided by decoration/staining of the nuclear envelope in both thyroid and breast cancer, thus demonstrating how much it matters "to be in the right shape" when dealing with pathological diagnosis of cancer.

C1 finite elements on non-tensor-product 2d and 3d manifolds

PubMed Central

Nguyen, Thien; Karčiauskas, Kęstutis; Peters, Jörg

2015-01-01

Geometrically continuous (Gk) constructions naturally yield families of finite elements for isogeometric analysis (IGA) that are Ck also for non-tensor-product layout. This paper describes and analyzes one such concrete C1 geometrically generalized IGA element (short: gIGA element) that generalizes bi-quadratic splines to quad meshes with irregularities. The new gIGA element is based on a recently-developed G1 surface construction that recommends itself by its a B-spline-like control net, low (least) polynomial degree, good shape properties and reproduction of quadratics at irregular (extraordinary) points. Remarkably, for Poisson’s equation on the disk using interior vertices of valence 3 and symmetric layout, we observe O(h3) convergence in the L∞ norm for this family of elements. Numerical experiments confirm the elements to be effective for solving the trivariate Poisson equation on the solid cylinder, deformations thereof (a turbine blade), modeling and computing geodesics on smooth free-form surfaces via the heat equation, for solving the biharmonic equation on the disk and for Koiter-type thin-shell analysis. PMID:26594070

C1 finite elements on non-tensor-product 2d and 3d manifolds.

PubMed

Nguyen, Thien; Karčiauskas, Kęstutis; Peters, Jörg

2016-01-01

Geometrically continuous ( G k ) constructions naturally yield families of finite elements for isogeometric analysis (IGA) that are C k also for non-tensor-product layout. This paper describes and analyzes one such concrete C 1 geometrically generalized IGA element (short: gIGA element) that generalizes bi-quadratic splines to quad meshes with irregularities. The new gIGA element is based on a recently-developed G 1 surface construction that recommends itself by its a B-spline-like control net, low (least) polynomial degree, good shape properties and reproduction of quadratics at irregular (extraordinary) points. Remarkably, for Poisson's equation on the disk using interior vertices of valence 3 and symmetric layout, we observe O ( h 3 ) convergence in the L ∞ norm for this family of elements. Numerical experiments confirm the elements to be effective for solving the trivariate Poisson equation on the solid cylinder, deformations thereof (a turbine blade), modeling and computing geodesics on smooth free-form surfaces via the heat equation, for solving the biharmonic equation on the disk and for Koiter-type thin-shell analysis.

Ingestion and Egestion of Microplastics by the Cladoceran Daphnia magna: Effects of Regular and Irregular Shaped Plastic and Sorbed Phenanthrene.

PubMed

Frydkjær, Camilla Krogh; Iversen, Niels; Roslev, Peter

2017-12-01

The presence of microplastics in aquatic ecosystems is of increasing global concern. This study investigated ingestion, egestion and acute effects of polyethylene microplastics in Daphnia magna. Fate of regular shaped microplastic beads (10-106 µm) were compared with irregular shaped microplastic fragments (10-75 µm). Daphnia magna ingested regular and irregular microplastic with uptake between 0.7 and 50 plastic particles/animal/day when exposed to microplastic concentrations of 0.0001-10 g/L. Egestion of irregular fragments was slower than that of microplastic beads. The EC50 for irregular microplastic was 0.065 g/L whereas microplastic beads were less inhibitory. The potential of microplastic to act as vector for hydrophobic pollutants was examined using [ 14 C]phenanthrene as tracer. Polyethylene microplastic sorbed less [ 14 C]phenanthrene compared to natural plankton organisms (bacteria, algae, yeast). As microplastics are much less abundant in most aquatic ecosystems compared to plankton organisms this suggests a limited role as vector for hydrophobic pollutants under current environmental conditions.

78 FR 44917 - Anchorage Regulations; Port of New York

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-25

... Anchorage Ground No. 27(iii) Flynns Knoll, near Sandy Hook, NJ. The irregular shaped area of Anchorage... nautical miles wide). The irregular bowl-shaped area of Anchorage Ground No. 27(iii) Flynns Knoll is about... and property of both the anchored vessels and those operating in the area as well as provide for the...

Using Chebyshev polynomial interpolation to improve the computational efficiency of gravity models near an irregularly-shaped asteroid

NASA Astrophysics Data System (ADS)

Hu, Shou-Cun; Ji, Jiang-Hui

2017-12-01

In asteroid rendezvous missions, the dynamical environment near an asteroid’s surface should be made clear prior to launch of the mission. However, most asteroids have irregular shapes, which lower the efficiency of calculating their gravitational field by adopting the traditional polyhedral method. In this work, we propose a method to partition the space near an asteroid adaptively along three spherical coordinates and use Chebyshev polynomial interpolation to represent the gravitational acceleration in each cell. Moreover, we compare four different interpolation schemes to obtain the best precision with identical initial parameters. An error-adaptive octree division is combined to improve the interpolation precision near the surface. As an example, we take the typical irregularly-shaped near-Earth asteroid 4179 Toutatis to demonstrate the advantage of this method; as a result, we show that the efficiency can be increased by hundreds to thousands of times with our method. Our results indicate that this method can be applicable to other irregularly-shaped asteroids and can greatly improve the evaluation efficiency.

Electron beam-induced radiation damage: the bubbling response in amorphous dried sodium phosphate buffer.

PubMed

Massover, William H

2010-06-01

Irradiation of an amorphous layer of dried sodium phosphate buffer (pH = 7.0) by transmission electron microscopy (100-120 kV) causes rapid formation of numerous small spherical bubbles [10-100 A (= 1-10 nm)] containing an unknown gas. Bubbling is detected even with the first low-dose exposure. In a thin layer (ca. 100-150 A), bubbling typically goes through nucleation, growth, possible fusion, and end-state, after which further changes are not apparent; co-irradiated adjacent areas having a slightly smaller thickness never develop bubbles. In moderately thicker regions (ca. over 200 A), there is no end-state. Instead, a complex sequence of microstructural changes is elicited during continued intermittent high-dose irradiation: nucleation, growth, early simple fusions, a second round of extensive multiple fusions, general reduction of matrix thickness (producing flattening and expansion of larger bubbles, occasional bubble fission, and formation of very large irregularly-shaped bubbles by a third round of compound fusion events), and slow shrinkage of all bubbles. The ongoing lighter appearance of bubble lumens, maintenance of their rounded shape, and extensive changes in size and form indicate that gas content continues throughout their surprisingly long lifetime; the thin dense boundary layer surrounding all bubbles is proposed to be the main mechanism for their long lifetime.

Temperature dependent barrier height and ideality factor of electrodeposited n-CdSe/Cu Schottky barrier diode

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

Mahato, S., E-mail: som.phy.ism@gmail.com; Shiwakoti, N.; Kar, A. K.

2015-06-24

This article reports the measurement of temperature-dependent barrier height and ideality factor of n-CdSe/Cu Schottky barrier diode. The Cadmium Selenide (CdSe) thin films have been deposited by simple electrodeposition technique. The XRD measurements ravels the deposited single phase CdSe films are highly oriented on (002) plane and the average particle size has been calculated to be ~18 nm. From SEM characterization, it is clear that the surface of CdSe thin films are continuous, homogeneous and the film is well adhered to the substrate and consists of fine grains which are irregular in shape and size. Current-Voltage characteristics have been measured atmore » different temperatures in the range (298 K – 353 K). The barrier height and ideality factor are found to be strongly temperature dependent. The inhomogenious barrier height increases and ideality factor decreases with increase in temperature. The expectation value has been calculated and its value is 0.30 eV.« less

Stretchable and Tunable Microtectonic ZnO-Based Sensors and Photonics.

PubMed

Gutruf, Philipp; Zeller, Eike; Walia, Sumeet; Nili, Hussein; Sriram, Sharath; Bhaskaran, Madhu

2015-09-16

The concept of realizing electronic applications on elastically stretchable "skins" that conform to irregularly shaped surfaces is revolutionizing fundamental research into mechanics and materials that can enable high performance stretchable devices. The ability to operate electronic devices under various mechanically stressed states can provide a set of unique functionalities that are beyond the capabilities of conventional rigid electronics. Here, a distinctive microtectonic effect enabled oxygen-deficient, nanopatterned zinc oxide (ZnO) thin films on an elastomeric substrate are introduced to realize large area, stretchable, transparent, and ultraportable sensors. The unique surface structures are exploited to create stretchable gas and ultraviolet light sensors, where the functional oxide itself is stretchable, both of which outperform their rigid counterparts under room temperature conditions. Nanoscale ZnO features are embedded in an elastomeric matrix function as tunable diffraction gratings, capable of sensing displacements with nanometre accuracy. These devices and the microtectonic oxide thin film approach show promise in enabling functional, transparent, and wearable electronics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Newly Designed Upper Lateral Cartilage Flap for Preventing Depression of the Keystone Area in Large-Nose Septorhinoplasty.

PubMed

Sharafi, Maryam; Jalessi, Maryam; Adamson, Peter A

2015-01-01

Because large dorsal reduction may weaken the keystone area, later notching of this area should be prevented while reducing large humps during septorhinoplasty. To determine whether a triangular-shaped flap of upper lateral cartilages (ULCs) that we designed can prevent secondary deformity of the nasal dorsum in the keystone area following large hump reduction. In this retrospective study, medical records as well as preoperative and postoperative photographs of septorhinoplasty cases in which triangular flaps had been used between April 1, 2012, and March 3, 2013, were reviewed. Data analysis was conducted from March 3 to May 10, 2014. Demographic data, amount of hump reduction, and any irregularity of the dorsum in the keystone area mentioned in the medical record or identified in postoperative profile view photographs were assessed. The study was conducted in a research center, and the operations were performed in a private setting. Patients had been scheduled for septorhinoplasty with flap reconstruction if more than 3 mm of dorsal hump reduction was planned and their skin was not thin. Of 41 identified patients, 3 could not be monitored for 1 year; 38 patients were included in the analysis. Open septorhinoplasty had been performed, and more than 3 mm of dorsum had been removed in all patients whose data were analyzed. During stepwise resection of the nasal dorsum, a triangular-shaped remnant of the most cephalomedial part of the ULC was maintained intact on each side over the keystone area. Irregularity of the nasal dorsum over the keystone area in postoperative profile view photographs. More than 3 mm of hump reduction had been made in all 38 patients. No irregularities were observed in the postoperative photographs or had been found on digital examination of the keystone area after at least 12 months of follow-up. Maintaining a remnant of the ULC over the keystone area in the form of a triangular-shaped flap on each side is a simple, reliable, and durable way to prevent notching of the keystone area during lowering of the nasal dorsum in large noses with sufficient skin thickness. 4.

Toxicological effects of irregularly shaped and spherical microplastics in a marine teleost, the sheepshead minnow (Cyprinodon variegatus).

PubMed

Choi, Jin Soo; Jung, Youn-Joo; Hong, Nam-Hui; Hong, Sang Hee; Park, June-Woo

2018-04-01

The increasing global contamination of plastics in marine environments is raising public concerns about the potential hazards of microplastics to environmental and human health. Microplastics formed by the breakdown of larger plastics are typically irregular in shape. The objective of this study was to compare the effects of spherical or irregular shapes of microplastics on changes in organ distribution, swimming behaviors, gene expression, and enzyme activities in sheepshead minnow (Cyprinodon variegatus). Both types of microplastics accumulated in the digestive system, causing intestinal distention. However, when compared to spherical microplastics, irregular microplastics decreased swimming behavior (i.e., total distance travelled and maximum velocity) of sheepshead minnow. Both microplastics generated cellular reactive oxygen species (ROS), while ROS-related molecular changes (i.e., transcriptional and enzymatic characteristics) differed. This study provides toxicological insights into the impacts of environmentally relevant (fragmented) microplastics on fish and improves our understanding of the environmental effects of microplastics in the ecosystem. Copyright © 2018 Elsevier Ltd. All rights reserved.

Galileo encounter with 951 Gaspra: First pictures of an asteroid

USGS Publications Warehouse

Belton, M.J.S.; Veverka, J.; Thomas, P.; Helfenstein, P.; Simonelli, D.; Chapman, C.; Davies, M.E.; Greeley, R.; Greenberg, R.; Head, J.; Murchie, S.; Klaasen, K.; Johnson, T.V.; McEwen, A.; Morrison, D.; Neukum, G.; Fanale, F.; Anger, C.; Carr, M.; Pilcher, C.

1992-01-01

Galileo images of Gaspra reveal it to be an irregularly shaped object (19 by 12 by 11 kilometers) that appears to have been created by a catastrophic collisional disruption of a precursor parent body. The cratering age of the surface is about 200 million years. Subtle albedo and color variations appear to correlate with morphological features: Brighter materials are associated with craters especially along the crests of ridges, have a stronger 1-micrometer absorption, and may represent freshly excavated mafic materials; darker materials exhibiting a significantly weaker 1-micrometer absorption appear concentrated in interridge areas. One explanation of these patterns is that Gaspra is covered with a thin regolith and that some of this material has migrated downslope in some areas.

Fractal morphometry of cell complexity.

PubMed

Losa, Gabriele A

2002-01-01

Irregularity and self-similarity under scale changes are the main attributes of the morphological complexity of both normal and abnormal cells and tissues. In other words, the shape of a self-similar object does not change when the scale of measurement changes, because each part of it looks similar to the original object. However, the size and geometrical parameters of an irregular object do differ when it is examined at increasing resolution, which reveals more details. Significant progress has been made over the past three decades in understanding how irregular shapes and structures in the physical and biological sciences can be analysed. Dominant influences have been the discovery of a new practical geometry of Nature, now known as fractal geometry, and the continuous improvements in computation capabilities. Unlike conventional Euclidean geometry, which was developed to describe regular and ideal geometrical shapes which are practically unknown in nature, fractal geometry can be used to measure the fractal dimension, contour length, surface area and other dimension parameters of almost all irregular and complex biological tissues. We have used selected examples to illustrate the application of the fractal principle to measuring irregular and complex membrane ultrastructures of cells at specific functional and pathological stage.

Electromagnetic properties of material coated surfaces

NASA Technical Reports Server (NTRS)

Beard, L.; Berrie, J.; Burkholder, R.; Dominek, A.; Walton, E.; Wang, N.

1989-01-01

The electromagnetic properties of material coated conducting surfaces were investigated. The coating geometries consist of uniform layers over a planar surface, irregularly shaped formations near edges and randomly positioned, electrically small, irregularly shaped formations over a surface. Techniques to measure the scattered field and constitutive parameters from these geometries were studied. The significance of the scattered field from these geometries warrants further study.

Unconventional maar diatreme and associated intrusions in the soft sediment-hosted Mardoux structure (Gergovie, France)

NASA Astrophysics Data System (ADS)

Valentine, Greg A.; van Wyk de Vries, Benjamin

2014-03-01

A Miocene age volcanic-hypabyssal structure comprising volcaniclastic deposits and mafic intrusions is exposed with vertical relief of ˜110 m on the side of Gergovie Plateau (Auvergne, France). Three main volcaniclastic facies are: (1) Fluidal tuff breccia composed of juvenile basalt and sediment clasts with dominantly fluidal shapes, with several combinations of basalt and sediment within individual clasts. (2) Thickly bedded lapilli tuff composed of varying proportions of fine-grained sediment derived from Oligocene-Miocene lacustrine marls and mudstones and basaltic lapilli, blocks, and bombs. (3) Planar-bedded tuff forming thin beds of fine to coarse ash-size sedimentary material and basalt clasts. Intrusive bodies in the thickly bedded lapilli tuff range from irregularly shaped and anastomosing dikes and sills of meters to tens of meters in length, to a main feeder dike that is up to ˜20 m wide, and that flares into a spoon-shaped sill at ˜100 m in diameter and 10-20 m thick in the eastern part of the structure. Volcaniclastic deposits and structural features suggest that ascending magma entrained soft, saturated sediment host material into the feeder dike and erupted fluidal magma and wet sediment via weak, Strombolian-like explosions. Host sediment and erupted material subsided to replace the extracted sediments, producing the growth subsidence structure that is similar to upper diatreme facies in typical maar diatremes but lacks evidence for explosive disruption of diatreme fill. Irregularly shaped small intrusions extended from the main feeder dike into the diatreme, and many were disaggregated due to shifting and subsidence of diatreme fill and recycled via eruption. The Mardoux structure is an "unconventional" maar diatreme in that it was produced mainly by weak explosive activity rather than by violent phreatomagmatic explosions and is an example of complex coupling between soft sediment and ascending magma.

Kinetic Shapes: Analysis, Verification, and Applications.

PubMed

Handz̆ić, Ismet; Reed, Kyle B

2014-06-01

A circular shape placed on an incline will roll; similarly, an irregularly shaped object, such as the Archimedean spiral, will roll on a flat surface when a force is applied to its axle. This rolling is dependent on the specific shape and the applied force (magnitude and location). In this paper, we derive formulas that define the behavior of irregular 2D and 3D shapes on a flat plane when a weight is applied to the shape's axle. These kinetic shape (KS) formulas also define and predict shapes that exert given ground reaction forces when a known weight is applied at the axle rotation point. Three 2D KS design examples are physically verified statically with good correlation to predicted values. Motion simulations of unrestrained 2D KS yielded expected results in shape dynamics and self-stabilization. We also put forth practical application ideas and research for 2D and 3D KS such as in robotics and gait rehabilitation.

Retrospective case series of the imaging findings of facial nerve hemangioma.

PubMed

Yue, Yunlong; Jin, Yanfang; Yang, Bentao; Yuan, Hui; Li, Jiandong; Wang, Zhenchang

2015-09-01

The aim was to compare high-resolution computed tomography (HRCT) and thin-section magnetic resonance imaging (MRI) findings of facial nerve hemangioma. The HRCT and MRI characteristics of 17 facial nerve hemangiomas diagnosed between 2006 and 2013 were retrospectively analyzed. All patients included in the study suffered from a space-occupying lesion of soft tissues at the geniculate ganglion fossa. Affected nerve was compared for size and shape with the contralateral unaffected nerve. HRCT showed irregular expansion and broadening of the facial nerve canal, damage of the bone wall and destruction of adjacent bone, with "point"-like or "needle"-like calcifications in 14 cases. The average CT value was 320.9 ± 141.8 Hu. Fourteen patients had a widened labyrinthine segment; 6/17 had a tympanic segment widening; 2/17 had a greater superficial petrosal nerve canal involvement, and 2/17 had an affected internal auditory canal (IAC) segment. On MRI, all lesions were significantly enhanced due to high blood supply. Using 2D FSE T2WI, the lesion detection rate was 82.4 % (14/17). 3D fast imaging employing steady-state acquisition (3D FIESTA) revealed the lesions in all patients. HRCT showed that the average number of involved segments in the facial nerve canal was 2.41, while MRI revealed an average of 2.70 segments (P < 0.05). HRCT and MR findings of facial nerve hemangioma were typical, revealing irregular masses growing along the facial nerve canal, with calcifications and rich blood supply. Thin-section enhanced MRI was more accurate in lesion detection and assessment compared with HRCT.

Photopolymerization of complex emulsions with irregular shapes fabricated by multiplex coaxial flow focusing

NASA Astrophysics Data System (ADS)

Wu, Qiang; Yang, Chaoyu; Yang, Jianxin; Huang, Fangsheng; Liu, Guangli; Zhu, Zhiqiang; Si, Ting; Xu, Ronald X.

2018-02-01

We fabricate complex emulsions with irregular shapes in the microscale by a simple but effective multiplex coaxial flow focusing process. A multiphase cone-jet structure is steadily formed, and the compound liquid jet eventually breaks up into Janus microdroplets due to the perturbations propagating along the jet interfaces. The microdroplet shapes can be exclusively controlled by interfacial tensions of adjacent phases. Crescent-moon-shaped microparticles and microcapsules with designated structural characteristics are further produced under ultraviolet light of photopolymerization after removing one hemisphere of the Janus microdroplets. These complex emulsions have potential applications in bioscience, food, functional materials, and controlled drug delivery.

Cartography of irregularly shaped satellites

NASA Technical Reports Server (NTRS)

Batson, R. M.; Edwards, Kathleen

1987-01-01

Irregularly shaped satellites, such as Phobos and Amalthea, do not lend themselves to mapping by conventional methods because mathematical projections of their surfaces fail to convey an accurate visual impression of the landforms, and because large and irregular scale changes make their features difficult to measure on maps. A digital mapping technique has therefore been developed by which maps are compiled from digital topographic and spacecraft image files. The digital file is geometrically transformed as desired for human viewing, either on video screens or on hard copy. Digital files of this kind consist of digital images superimposed on another digital file representing the three-dimensional form of a body.

Preparation of Regular Specimens for Atom Probes

NASA Technical Reports Server (NTRS)

Kuhlman, Kim; Wishard, James

2003-01-01

A method of preparation of specimens of non-electropolishable materials for analysis by atom probes is being developed as a superior alternative to a prior method. In comparison with the prior method, the present method involves less processing time. Also, whereas the prior method yields irregularly shaped and sized specimens, the present developmental method offers the potential to prepare specimens of regular shape and size. The prior method is called the method of sharp shards because it involves crushing the material of interest and selecting microscopic sharp shards of the material for use as specimens. Each selected shard is oriented with its sharp tip facing away from the tip of a stainless-steel pin and is glued to the tip of the pin by use of silver epoxy. Then the shard is milled by use of a focused ion beam (FIB) to make the shard very thin (relative to its length) and to make its tip sharp enough for atom-probe analysis. The method of sharp shards is extremely time-consuming because the selection of shards must be performed with the help of a microscope, the shards must be positioned on the pins by use of micromanipulators, and the irregularity of size and shape necessitates many hours of FIB milling to sharpen each shard. In the present method, a flat slab of the material of interest (e.g., a polished sample of rock or a coated semiconductor wafer) is mounted in the sample holder of a dicing saw of the type conventionally used to cut individual integrated circuits out of the wafers on which they are fabricated in batches. A saw blade appropriate to the material of interest is selected. The depth of cut and the distance between successive parallel cuts is made such that what is left after the cuts is a series of thin, parallel ridges on a solid base. Then the workpiece is rotated 90 and the pattern of cuts is repeated, leaving behind a square array of square posts on the solid base. The posts can be made regular, long, and thin, as required for samples for atom-probe analysis. Because of their small volume and regularity, the amount of FIB-milling time can be much less than that of the method of sharp shards. Individual posts can be broken off for mounting in a manner similar to that of the method of sharp shards. Alternatively, the posts can be left intact on the base and the base can be cut to a small square (e.g., 3 by 3 mm) suitable for mounting in an atom probe of a type capable of accepting multiple-tip specimens. The advantage of multiple-tip specimens is the possibility of analyzing many tips without the time-consuming interchange of specimens.

Case history of an opposed-bore, dual horizontal well in the Austin Chalk formation of south Texas

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

Cooney, M.F.; Rogers, C.T.; Stacey, E.S.

1993-03-01

Petro-Hunt Corp. used a unique horizontal-well design to optimize development of an irregularly shaped lease in the Austin chalk formation in Texas. Two medium-radius horizontal bores were drilled in opposite directions from one vertical hole to maximize horizontal displacement in the lease. Underbalanced drilling techniques were used to prevent formation damage. The well design resulted in a significant cost savings per horizontal foot compared with 24 offset wells that the operator drilled. This paper reviews well planning and drilling and emphasizes techniques used to intersect thin horizontal targets and to initiate the second horizontal bore. Production results and drilling economicsmore » are discussed briefly, and ideas on future dual-horizontal-well applications are presented.« less

Various Silver Nanostructures on Sapphire Using Plasmon Self-Assembly and Dewetting of Thin Films

NASA Astrophysics Data System (ADS)

Kunwar, Sundar; Sui, Mao; Zhang, Quanzhen; Pandey, Puran; Li, Ming-Yu; Lee, Jihoon

2017-04-01

Silver (Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices. The target application and the performance can be inherently tuned by control of configuration, shape, and size of Ag nanostructures. In this work, we demonstrate the systematical fabrication of various configurations of Ag nanostructures on sapphire (0001) by controlling the Ag deposition thickness at different annealing environments in a plasma ion coater. In particular, the evolution of Ag particles (between 2 and 20 nm), irregular nanoclusters (between 30 and 60 nm), and nanocluster networks (between 80 and 200 nm) are found be depended on the thickness of Ag thin film. The results were systematically analyzed and explained based on the solid-state dewetting, surface diffusion, Volmer-Weber growth model, coalescence, and surface energy minimization mechanism. The growth behavior of Ag nanostructures is remarkably differentiated at higher annealing temperature (750 °C) due to the sublimation and temperature-dependent characteristic of dewetting process. In addition, Raman and reflectance spectra analyses reveal that optical properties of Ag nanostructures depend on their morphology.

Self-Sealed Bionic Long Microchannels with Thin Walls and Designable Nanoholes Prepared by Line-Contact Capillary-Force Assembly.

PubMed

Lao, Zhao-Xin; Hu, Yan-Lei; Pan, Deng; Wang, Ren-Yan; Zhang, Chen-Chu; Ni, Jin-Cheng; Xu, Bing; Li, Jia-Wen; Wu, Dong; Chu, Jia-Ru

2017-06-01

Long microchannels with thin walls, small width, and nanoholes or irregular shaped microgaps, which are similar to capillaries or cancerous vessels, are urgently needed to simulate the physiological activities in human body. However, the fabrication of such channels remains challenging. Here, microchannels with designable holes are manufactured by combining laser printing with line-contact capillary-force assembly. Two microwalls are first printed by femtosecond laser direct-writing, and subsequently driven to collapse into a channel by the capillary force that arises in the evaporation of developer. The channel can remain stable in solvent due to the enhanced Van der Waals' force caused by the line-contact of microwalls. Microchannels with controllable nanoholes and almost arbitrary patterns can be fabricated without any bonding or multistep processes. As-prepared microchannels, with wall thicknesses less than 1 µm, widths less than 3 µm, lengths more than 1 mm, are comparable with human capillaries. In addition, the prepared channels also exhibit the ability to steer the flow of liquid without any external pump. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In Situ Study of Strain-Dependent Ion Conductivity of Stretchable Polyethylene Oxide Electrolyte

PubMed Central

Kelly, Taylor; Ghadi, Bahar Moradi; Berg, Sean; Ardebili, Haleh

2016-01-01

There is a strong need in developing stretchable batteries that can accommodate stretchable or irregularly shaped applications including medical implants, wearable devices and stretchable electronics. Stretchable solid polymer electrolytes are ideal candidates for creating fully stretchable lithium ion batteries mainly due to their mechanical and electrochemical stability, thin-film manufacturability and enhanced safety. However, the characteristics of ion conductivity of polymer electrolytes during tensile deformation are not well understood. Here, we investigate the effects of tensile strain on the ion conductivity of thin-film polyethylene oxide (PEO) through an in situ study. The results of this investigation demonstrate that both in-plane and through-plane ion conductivities of PEO undergo steady and linear growths with respect to the tensile strain. The coefficients of strain-dependent ion conductivity enhancement (CSDICE) for in-plane and through-plane conduction were found to be 28.5 and 27.2, respectively. Tensile stress-strain curves and polarization light microscopy (PLM) of the polymer electrolyte film reveal critical insights on the microstructural transformation of stretched PEO and the potential consequences on ionic conductivity. PMID:26831948

Neptune

NASA Image and Video Library

1999-08-08

NASA Voyager 2 obtained these images of satellite 1989N2 and revealed it to be and irregularly shaped, dark object. The satellite appeared to have several craters. The irregular outline suggests that this moon has remained cold and rigid throughout much

Characterizing neural activities evoked by manual acupuncture through spiking irregularity measures

NASA Astrophysics Data System (ADS)

Xue, Ming; Wang, Jiang; Deng, Bin; Wei, Xi-Le; Yu, Hai-Tao; Chen, Ying-Yuan

2013-09-01

The neural system characterizes information in external stimulations by different spiking patterns. In order to examine how neural spiking patterns are related to acupuncture manipulations, experiments are designed in such a way that different types of manual acupuncture (MA) manipulations are taken at the ‘Zusanli’ point of experimental rats, and the induced electrical signals in the spinal dorsal root ganglion are detected and recorded. The interspike interval (ISI) statistical histogram is fitted by the gamma distribution, which has two parameters: one is the time-dependent firing rate and the other is a shape parameter characterizing the spiking irregularities. The shape parameter is the measure of spiking irregularities and can be used to identify the type of MA manipulations. The coefficient of variation is mostly used to measure the spike time irregularity, but it overestimates the irregularity in the case of pronounced firing rate changes. However, experiments show that each acupuncture manipulation will lead to changes in the firing rate. So we combine four relatively rate-independent measures to study the irregularity of spike trains evoked by different types of MA manipulations. Results suggest that the MA manipulations possess unique spiking statistics and characteristics and can be distinguished according to the spiking irregularity measures. These studies have offered new insights into the coding processes and information transfer of acupuncture.

Lumpy Janus

NASA Image and Video Library

2013-07-01

The Cassini spacecraft catches a glimpse of Janus, an irregularly shaped moon. Lacking sufficient gravity to pull itself into a round shape, Janus has had its lumpy primordial shape only slightly modified by impacts since its formation.

The shape of the F-region irregularities which produce satellite scintillations Evidence for axial asymmetry.

NASA Technical Reports Server (NTRS)

Moorcroft, D. R.; Arima, K. S.

1972-01-01

Correlation analysis of three-station observations of satellite amplitude scintillations, recorded at London, Canada during the summer of 1968, have been interpreted to give information on the height, size and shape of the ionospheric irregularities. The irregularities had a mean height of 390 km, and when interpreted in terms of the usual axially-symmetric, field-aligned model, had a mean axial ratio of 6.5, and a mean dimension transverse to the magnetic field of 0.7 km. None of these parameters showed any systematic trend with geomagnetic latitude. The data for one of the passes analyzed were inconsistent with axial symmetry, and when examined in terms of a more general model, 3 of 9 passes showed evidence of irregularities which were elongated both along and transverse to the earth's magnetic field, the elongation transverse to the field tending to lie in a north-south direction.

New aspects of the ionospheric irregularities observed with the Equatorial Atmosphere Radar

NASA Astrophysics Data System (ADS)

Fukao, S.

2003-04-01

Coherent radar observations of 3-m equatorial spread F (ESF) irregularities have been conducted with the Equatorial Atmosphere Radar (EAR) in the West Pacific (0.2oS, 100.32oW; geomagnetic latitude 10.63oS) since November 2002. The EAR has a peak output power of 100~kW and a circular antenna array approximately 110~m in diameter. An active phased-array antenna system enables it to view perpendicular to the geomagnetic field in a fan-shaped altitude-longitude sector which extends over 600~km at the altitude of 500~km. The purpose of this paper is to present some preliminary results obtained with this radar. First, the EAR observed that ESF irregularities with east-west scale sizes of 100-500~km usually appeared after sunset and traversed with a speed of the order of 100 m/s from west to east. They considerably changed their shapes, but the shapes of well-matured irregularities are, in general, quite similar to those inferred from altitude-time sections obtained simultaneously. Second, a tiny structure born within the sector was followed during its growth, and the growth rate was estimated to be 7x10-3/sec, the same order of magnitude as that of the gravitational Rayleigh-Taylor instability. Third, plasma bubbles as tall as 800~km in altitude (their maximum apex altitude is about 1300~km) appeared without being accompanied by any upwelling below which is usually observed at other longitudes. This result indicates that the ESF irregularities are first generated at the equator and rapidly rise upward involving higher latitude regions connected with the same geomagnetic field lines. Finally, an intense ESF irregularity was observed after sunrise, which moved first toward the pole and then disappeared to the west. Its growth rate is similar to the nocturnal irregularity. It will be interesting to investigate these new aspects of the ESF irregularities in this longitude for elucidation of their generation mechanism.

Postoperative corneal shape changes: microincision versus small-incision coaxial cataract surgery.

PubMed

Hayashi, Ken; Yoshida, Motoaki; Hayashi, Hideyuki

2009-02-01

To compare changes in corneal topography and in regular and irregular astigmatism after coaxial clear corneal microincision cataract surgery (MICS) and after coaxial small-incision cataract surgery (SICS). Hayashi Eye Hospital, Fukuoka, Japan. Induced corneal astigmatism was determined using vector analysis. The averaged corneal shape changes and degree of irregular astigmatism were examined using videokeratography preoperatively as well as 2 days and 1, 2, 4, and 8 weeks postoperatively. One hundred twenty eyes of 60 patients scheduled for phacoemulsification were evaluated. Sixty eyes had MICS (2.00 mm), and the 60 contralateral eyes had SICS (2.65 mm). The mean induced corneal astigmatism was significantly less in the MICS group than in the SICS group (P

Gravitational perturbation of irregular bodies modeled with regular polyhedra

NASA Astrophysics Data System (ADS)

Venditti, Flaviane; Prado, Antonio

In this work the study of the dynamics around bodies with non-spherical shapes is considered. The gravitational field of an irregular body, meaning that the mass distribution is asymmetric, generates orbits around this body to perform different from a keplerian orbit. In this case, there is a perturbation on the gravitational field that must be analyzed. To know the gravitational force of an irregular object, first it is necessary to model this body, which is not an easy thing to do, considering that, usually, they are not symmetric figures. To better model the irregular objects, a combination of several geometric figures can be used, like parallelepipeds. This can be applied to asteroids, which are objects with non-spherical shapes. The disturbing force generated by these bodies can then be obtained as the sum of the force on each figure. Here the equation for the potential of a cube is considered (MacMillan, 1930), which makes it possible to have analytical results. The main idea is to build a body with several cubes, and having the gravitational potential of each cube, it is possible to obtain the total perturbation as the sum of the forces acting on each piece. This methodology can be very helpful on space missions to small bodies, because when a spacecraft is in the vicinity of an irregular body, the gravitational perturbation generated by its shape must be considered to compensate this effect.

Traveling in the dark: the legibility of a regular and predictable structure of the environment extends beyond its borders.

PubMed

Yaski, Osnat; Portugali, Juval; Eilam, David

2012-04-01

The physical structure of the surrounding environment shapes the paths of progression, which in turn reflect the structure of the environment and the way that it shapes behavior. A regular and coherent physical structure results in paths that extend over the entire environment. In contrast, irregular structure results in traveling over a confined sector of the area. In this study, rats were tested in a dark arena in which half the area contained eight objects in a regular grid layout, and the other half contained eight objects in an irregular layout. In subsequent trials, a salient landmark was placed first within the irregular half, and then within the grid. We hypothesized that rats would favor travel in the area with regular order, but found that activity in the area with irregular object layout did not differ from activity in the area with grid layout, even when the irregular half included a salient landmark. Thus, the grid impact in one arena half extended to the other half and overshadowed the presumed impact of the salient landmark. This could be explained by mechanisms that control spatial behavior, such as grid cells and odometry. However, when objects were spaced irregularly over the entire arena, the salient landmark became dominant and the paths converged upon it, especially from objects with direct access to the salient landmark. Altogether, three environmental properties: (i) regular and predictable structure; (ii) salience of landmarks; and (iii) accessibility, hierarchically shape the paths of progression in a dark environment. Copyright © 2012 Elsevier B.V. All rights reserved.

Possible stretched exponential parametrization for humidity absorption in polymers.

PubMed

Hacinliyan, A; Skarlatos, Y; Sahin, G; Atak, K; Aybar, O O

2009-04-01

Polymer thin films have irregular transient current characteristics under constant voltage. In hydrophilic and hydrophobic polymers, the irregularity is also known to depend on the humidity absorbed by the polymer sample. Different stretched exponential models are studied and it is shown that the absorption of humidity as a function of time can be adequately modelled by a class of these stretched exponential absorption models.

Penalized likelihood and multi-objective spatial scans for the detection and inference of irregular clusters

PubMed Central

2010-01-01

Background Irregularly shaped spatial clusters are difficult to delineate. A cluster found by an algorithm often spreads through large portions of the map, impacting its geographical meaning. Penalized likelihood methods for Kulldorff's spatial scan statistics have been used to control the excessive freedom of the shape of clusters. Penalty functions based on cluster geometry and non-connectivity have been proposed recently. Another approach involves the use of a multi-objective algorithm to maximize two objectives: the spatial scan statistics and the geometric penalty function. Results & Discussion We present a novel scan statistic algorithm employing a function based on the graph topology to penalize the presence of under-populated disconnection nodes in candidate clusters, the disconnection nodes cohesion function. A disconnection node is defined as a region within a cluster, such that its removal disconnects the cluster. By applying this function, the most geographically meaningful clusters are sifted through the immense set of possible irregularly shaped candidate cluster solutions. To evaluate the statistical significance of solutions for multi-objective scans, a statistical approach based on the concept of attainment function is used. In this paper we compared different penalized likelihoods employing the geometric and non-connectivity regularity functions and the novel disconnection nodes cohesion function. We also build multi-objective scans using those three functions and compare them with the previous penalized likelihood scans. An application is presented using comprehensive state-wide data for Chagas' disease in puerperal women in Minas Gerais state, Brazil. Conclusions We show that, compared to the other single-objective algorithms, multi-objective scans present better performance, regarding power, sensitivity and positive predicted value. The multi-objective non-connectivity scan is faster and better suited for the detection of moderately irregularly shaped clusters. The multi-objective cohesion scan is most effective for the detection of highly irregularly shaped clusters. PMID:21034451

A Model Based Deconvolution Approach for Creating Surface Composition Maps of Irregularly Shaped Bodies from Limited Orbiting Nuclear Spectrometer Measurements

NASA Astrophysics Data System (ADS)

Dallmann, N. A.; Carlsten, B. E.; Stonehill, L. C.

2017-12-01

Orbiting nuclear spectrometers have contributed significantly to our understanding of the composition of solar system bodies. Gamma rays and neutrons are produced within the surfaces of bodies by impacting galactic cosmic rays (GCR) and by intrinsic radionuclide decay. Measuring the flux and energy spectrum of these products at one point in an orbit elucidates the elemental content of the area in view. Deconvolution of measurements from many spatially registered orbit points can produce detailed maps of elemental abundances. In applying these well-established techniques to small and irregularly shaped bodies like Phobos, one encounters unique challenges beyond those of a large spheroid. Polar mapping orbits are not possible for Phobos and quasistatic orbits will realize only modest inclinations unavoidably limiting surface coverage and creating North-South ambiguities in deconvolution. The irregular shape causes self-shadowing both of the body to the spectrometer but also of the body to the incoming GCR. The view angle to the surface normal as well as the distance between the surface and the spectrometer is highly irregular. These characteristics can be synthesized into a complicated and continuously changing measurement system point spread function. We have begun to explore different model-based, statistically rigorous, iterative deconvolution methods to produce elemental abundance maps for a proposed future investigation of Phobos. By incorporating the satellite orbit, the existing high accuracy shape-models of Phobos, and the spectrometer response function, a detailed and accurate system model can be constructed. Many aspects of this model formation are particularly well suited to modern graphics processing techniques and parallel processing. We will present the current status and preliminary visualizations of the Phobos measurement system model. We will also discuss different deconvolution strategies and their relative merit in statistical rigor, stability, achievable resolution, and exploitation of the irregular shape to partially resolve ambiguities. The general applicability of these new approaches to existing data sets from Mars, Mercury, and Lunar investigations will be noted.

Form drag in rivers due to small-scale natural topographic features: 2. Irregular sequences

USGS Publications Warehouse

Kean, J.W.; Smith, J.D.

2006-01-01

The size, shape, and spacing of small-scale topographic features found on the boundaries of natural streams, rivers, and floodplains can be quite variable. Consequently, a procedure for determining the form drag on irregular sequences of different-sized topographic features is essential for calculating near-boundary flows and sediment transport. A method for carrying out such calculations is developed in this paper. This method builds on the work of Kean and Smith (2006), which describes the flow field for the simpler case of a regular sequence of identical topographic features. Both approaches model topographic features as two-dimensional elements with Gaussian-shaped cross sections defined in terms of three parameters. Field measurements of bank topography are used to show that (1) the magnitude of these shape parameters can vary greatly between adjacent topographic features and (2) the variability of these shape parameters follows a lognormal distribution. Simulations using an irregular set of topographic roughness elements show that the drag on an individual element is primarily controlled by the size and shape of the feature immediately upstream and that the spatial average of the boundary shear stress over a large set of randomly ordered elements is relatively insensitive to the sequence of the elements. In addition, a method to transform the topography of irregular surfaces into an equivalently rough surface of regularly spaced, identical topographic elements also is given. The methods described in this paper can be used to improve predictions of flow resistance in rivers as well as quantify bank roughness.

Effective description of domain wall strings

NASA Astrophysics Data System (ADS)

Rodrigues, Davi R.; Abanov, Ar.; Sinova, J.; Everschor-Sitte, K.

2018-04-01

The analysis of domain wall dynamics is often simplified to one-dimensional physics. For domain walls in thin films, more realistic approaches require the description as two-dimensional objects. This includes the study of vortices and curvatures along the domain walls as well as the influence of boundary effects. Here we provide a theory in terms of soft modes that allows us to analytically study the physics of extended domain walls and their stability. By considering irregularly shaped skyrmions as closed domain walls, we analyze their plasticity and compare their dynamics with those of circular skyrmions. Our theory directly provides an analytical description of the excitation modes of magnetic skyrmions, previously accessible only through sophisticated micromagnetic numerical calculations and spectral analysis. These analytical expressions provide the scaling behavior of the different physics on parameters that experiments can test.

Effects of target shape and impact speed on the outcome of catastrophic disruptions

NASA Astrophysics Data System (ADS)

Campo~Bagatin, A.; Durda, D.; Alemañ, R.; Flynn, G.; Strait, M.; Clayton, A.; Patmore, E.

2014-07-01

Because of the propensity of previous laboratory investigations to focus on idealized spherical targets, there is a bit of ambiguity in decoupling the relative importance/influence of low speed or spherical shape in producing the 'onion shell' fragment shape outcomes found in impacts into spherical targets [1,2]. If due primarily to impact speed/energy density as suggested by [3], this could play an important role in main-belt impacts due to the presence of non-spherical targets and non-negligible probability of low-speed (i.e., below about 3-4 km/s, subsonic in rock) impacts [4]. Also, [5] and [6] suggested that the shape of targets may affect the outcome of shattering processes, both in terms of fragment shape and mass distribution. To examine explicitly the effects of target shape in impact outcomes, we chose to conduct impact experiments on both spherical and naturally-occurring irregularly-shaped basalt targets. We impacted a total of six targets (two spheres and four irregular targets). We focused on shots with impact speeds in the ˜4 to 6 km/s range by 3/16th-inch diameter Al-sphere projectiles fired at the NASA AVGR. Following each shot, the debris were recovered (>95 %) and large fragments (>0.20 g) were individually weighed, allowing us to carefully measure the mass-frequency distribution from each impact experiment. The 36 largest fragments of each shot were photographed and their largest axes accurately measured by the program ''ImageJ''. Their shortest axes were measured by means of a digital caliber. High-speed video of each impact was obtained to aid interpretation of the fragmentation mode of the targets. Images clearly show that shell-like fragments can be produced in shattering events not in the target's surface. Instead, those fragments may form around the core, well inside the target structure, independently on the target shape itself. This is a feature not reported to date. In order to understand what the bulk macro-porosity of a non-coherent set of fragments is, we gathered randomly together the fragments with weighed mass mimicking the post-shattering gravitational re-accumulation of fragments into an asteroid rubble-pile. For each set, we wrapped the fragments in a thin plastic film and measured the bulk volume by hanging and plunging the assemblage into distilled water. The volume is calculated straightforward from the density of water at the given temperature. Cumulative mass distributions are derived and exponents 0.75<β <1.2 are found for the relationship N(>m)=A m^{-β} (m is the fragment mass, A is the corresponding constant) in the stationary part of the distribution. The exponent of each distribution and the mass of each largest fragment are found to be related to the corresponding specific energy of each impact as expected [3]. The mass distributions seem to show slightly larger values of β in the case of spherical targets when comparing two sets of close specific energy impacts. However, this feature needs further sets of impact experiments to be properly investigated. As for the shapes of fragments, b/a and c/a ratios were calculated along with the shape metrics Ψ=[ c^2/(ab)]^{1/3}, F=(a-b)/(a-c) for deviation from the spherical shape and relative flatness, respectively [7,8]. The average relationship between a, b, and c axes is 1:0.7:0.4, slightly different (flatter) than reported by former investigations (1:0.7:0.5) carried on in the 70s and 80s [7]. This result is quite stable and no differences are found in average shapes among spherical and irregular targets nor for different specific energy up to a factor of ˜3. This does not mean that fragments look like triaxial ellipsoids, instead they are quite irregular but their average relative sizes are distributed very nicely as described. Finally, the study of the macro-porosities of randomly aggregated fragments shows values in the 45 to 50 % range. This result may be useful in the interpretation of small asteroids' bulk densities and in the calibration of numerical modelling of internal structures.

Light Scattering by Gaussian Particles: A Solution with Finite-Difference Time Domain Technique

NASA Technical Reports Server (NTRS)

Sun, W.; Nousiainen, T.; Fu, Q.; Loeb, N. G.; Videen, G.; Muinonen, K.

2003-01-01

The understanding of single-scattering properties of complex ice crystals has significance in atmospheric radiative transfer and remote-sensing applications. In this work, light scattering by irregularly shaped Gaussian ice crystals is studied with the finite-difference time-domain (FDTD) technique. For given sample particle shapes and size parameters in the resonance region, the scattering phase matrices and asymmetry factors are calculated. It is found that the deformation of the particle surface can significantly smooth the scattering phase functions and slightly reduce the asymmetry factors. The polarization properties of irregular ice crystals are also significantly different from those of spherical cloud particles. These FDTD results could provide a reference for approximate light-scattering models developed for irregular particle shapes and can have potential applications in developing a much simpler practical light scattering model for ice clouds angular-distribution models and for remote sensing of ice clouds and aerosols using polarized light. (copyright) 2003 Elsevier Science Ltd. All rights reserved.

Identifying irregularly shaped crime hot-spots using a multiobjective evolutionary algorithm

NASA Astrophysics Data System (ADS)

Wu, Xiaolan; Grubesic, Tony H.

2010-12-01

Spatial cluster detection techniques are widely used in criminology, geography, epidemiology, and other fields. In particular, spatial scan statistics are popular and efficient techniques for detecting areas of elevated crime or disease events. The majority of spatial scan approaches attempt to delineate geographic zones by evaluating the significance of clusters using likelihood ratio statistics tested with the Poisson distribution. While this can be effective, many scan statistics give preference to circular clusters, diminishing their ability to identify elongated and/or irregular shaped clusters. Although adjusting the shape of the scan window can mitigate some of these problems, both the significance of irregular clusters and their spatial structure must be accounted for in a meaningful way. This paper utilizes a multiobjective evolutionary algorithm to find clusters with maximum significance while quantitatively tracking their geographic structure. Crime data for the city of Cincinnati are utilized to demonstrate the advantages of the new approach and highlight its benefits versus more traditional scan statistics.

Ore microscopy of the Paoli silver-copper deposit, Oklahoma

USGS Publications Warehouse

Thomas, C.A.; Hagni, R.D.; Berendsen, P.

1991-01-01

The Paoli silver-copper deposit is located in south-central Oklahoma, 56 km south-southeast from Norman, Oklahoma. It was mined for high-grade silver-copper near the beginning of this century, and intensive exploratory drilling during the early 1970's delineated unmined portions of the deposit. A collaborative study between the U.S.G.S., the Kansas Geological Survey, and the University of Missouri-Rolla was undertaken to provide new information on the character of red bed copper deposits of the Midcontinent region. The Paoli deposit has been interpreted to occur as a roll-front type of deposit. The silver and copper mineralization occurs within paleochannels in the Permian Wellington Formation. The silver-copper interfaces appear to be controlled by oxidation-reduction interfaces that are marked by grey to red color changes in the host sandstone. Ore microscopic examinations of polished thin sections show that unoxidized ore consists of chalcocite, digenite, chalcopyrite, covellite and pyrite; and oxidized ores are characterized by covellite, bornite, hematite and goethite. In sandstone-hosted ores, chalcocite and digenite replace dolomite and border clastic quartz grains. In siltstone-hosted ores, the copper sulfide grains have varied shapes; most are irregular in shape and 5-25 ??m across, others have euhedral shapes suggestive of pyrite crystal replacements, and some are crudely spherical and are 120-200 ??m across. Chalcopyrite is the predominant copper sulfide at depth. Covellite and malachite replace chalcocite and digenite near the surface. Silver only occurs as native silver; most as irregularly shaped grains 40-80 ??m across, but some as cruciform crystals that are up to 3.5 mm across. The native silver has been deposited after copper sulfides, and locally replaces chalcocite. Surficial nodules of pyrite, malachite and hematite locally are present in outcrops at the oxidation-reduction fronts. Polished sections of the nodules show that malachite forms a cement around quartz sand grains, and brecciated pyrite grains are surrounded by rims of hematite and goethite. Dolomite is the principal sandstone cement. Cathodoluminescence microscopic study of the mineral has shown that it was deposited during seven periods before the copper sulfide mineralization. ?? 1991.

Congenital tri-cavernous hemangiomas of the right buccal region, right accessory parotid gland, and masseter muscle region.

PubMed

Yang, Tao; Gu, Yongchun; Zhang, Li; Hua, Zequan

2014-03-01

We report a rare case of congenital tri-cavernous hemangiomas of the right buccal region, right accessory parotid gland, and masseter muscle region in an adult. The patient, a 25-year-old woman, complained of 3 masses in her right midcheek. Ultrasonographic and computed tomographic findings showed an irregular-shaped mass (multiple calcifications) with a well-defined margin in the masseter muscle region, an ellipse-shaped mass (multiple calcifications) with a well-defined margin in the right buccal region, and a comma-shaped mass (no calcifications) with a well-defined margin separate from the parotid gland in the right accessory parotid gland region. These iconographic findings suggested that the masses were all hemangiomas separately originating from the parotid gland, accessory parotid gland, and masseter muscle. The masses were completely removed through a standard parotid incision without postoperative facial palsy, skin deformity, and difficulty in secreting saliva. Findings from histologic examination of the tumor revealed multiple, thin-walled, and dilated blood vessels, confirming the diagnosis of cavernous hemangiomas. Ultrasonographic and computed tomographic findings were extremely useful in diagnosing the mass/masses as hemangioma before surgery, clarifying relationships between the mass and adjacent structures, and determining the surgical approach to the mass/masses.

Evaluation of phase transformation in ferromagnetic shape memory Fe-Pd alloy by magnetic Barkhausen noise

NASA Astrophysics Data System (ADS)

Furuya, Yasubumi; Tamoto, Shizuka; Kubota, Takeshi; Okazaki, Teiko; Hagood, Nesbitt W.; Spearing, S. Mark

2002-07-01

The possibility to detect the phase transformation with martensites by heating or cooling as well as stress-loading in ferromagnetic shape memory Fe-30at percent Pd alloy thin foil by using magnetic Markhausen noise sensor was studied. MBHN is caused by the irregular interactions between magnetic domain and thermally activated martensite twins during magnetization. In general, the envelope of the MBHN voltage versus time signals in Fe-29at percent Pd ribbon showed two peaks during magnetization, where secondary peak at intermediate state of magnetization process decreased with increasing temperature, while the MBHN envelopes in pure iron did not change with increasing temperature. The variety of MBHN due to the phase transformation was apt to arise at higher frequency part of spectrum during intermediate state of magnetization process and it decreased with disappearance of martensite twins. Besides, MBHN increased monotonically with increasing loading stress and then, it decreased with unloading, however MBHN showed large hysteresis between loading and unloading passes. Based on the experimental results from MBHN measurements for both thermoelastic and stress-induced martensite phase transformations in Fe-30at percent Pd ribbon samples, MBHN method seems a useful technique to non-destructive evaluation of martensite phase transformation of ferromagnetic shape memory alloy.

Shape evolution of a melting nonspherical particle

NASA Astrophysics Data System (ADS)

Kintea, Daniel M.; Hauk, Tobias; Roisman, Ilia V.; Tropea, Cameron

2015-09-01

In this study melting of irregular ice crystals was observed in an acoustic levitator. The evolution of the particle shape is captured using a high-speed video system. Several typical phenomena have been discovered: change of the particle shape, appearance of a capillary flow of the melted liquid on the particle surface leading to liquid collection at the particle midsection (where the interface curvature is smallest), and appearance of sharp cusps at the particle tips. No such phenomena can be observed during melting of spherical particles. An approximate theoretical model is developed which accounts for the main physical phenomena associated with melting of an irregular particle. The agreement between the theoretical predictions for the melting time, for the evolution of the particle shape, and the corresponding experimental data is rather good.

Output calculation of electron therapy at extended SSD using an improved LBR method.

PubMed

Alkhatib, Hassaan A; Gebreamlak, Wondesen T; Tedeschi, David J; Mihailidis, Dimitris; Wright, Ben W; Neglia, William J; Sobash, Philip T; Fontenot, Jonas D

2015-02-01

To calculate the output factor (OPF) of any irregularly shaped electron beam at extended SSD. Circular cutouts were prepared from 2.0 cm diameter to the maximum possible size for 15 × 15 applicator cone. In addition, two irregular cutouts were prepared. For each cutout, percentage depth dose (PDD) at the standard SSD and doses at different SSD values were measured using 6, 9, 12, and 16 MeV electron beam energies on a Varian 2100C LINAC and the distance at which the central axis electron fluence becomes independent of cutout size was determined. The measurements were repeated with an ELEKTA Synergy LINAC using 14 × 14 applicator cone and electron beam energies of 6, 9, 12, and 15 MeV. The PDD measurements were performed using a scanning system and two diodes-one for the signal and the other a stationary reference outside the tank. The doses of the circular cutouts at different SSDs were measured using PTW 0.125 cm(3) Semiflex ion-chamber and EDR2 films. The electron fluence was measured using EDR2 films. For each circular cutout, the lateral buildup ratio (LBR) was calculated from the measured PDD curve using the open applicator cone as the reference field. The effective SSD (SSDeff) of each circular cutout was calculated from the measured doses at different SSD values. Using the LBR value and the radius of the circular cutout, the corresponding lateral spread parameter [σR(z)] was calculated. Taking the cutout size dependence of σR(z) into account, the PDD curves of the irregularly shaped cutouts at the standard SSD were calculated. Using the calculated PDD curve of the irregularly shaped cutout along with the LBR and SSDeff values of the circular cutouts, the output factor of the irregularly shaped cutout at extended SSD was calculated. Finally, both the calculated PDD curves and output factor values were compared with the measured values. The improved LBR method has been generalized to calculate the output factor of electron therapy at extended SSD. The percentage difference between the calculated and the measured output factors of irregularly shaped cutouts in a clinical useful SSD region was within 2%. Similar results were obtained for all available electron energies of both Varian 2100C and ELEKTA Synergy machines.

Female pattern hair loss.

PubMed

Herskovitz, Ingrid; Tosti, Antonella

2013-10-01

Female pattern hair loss (FPHL) also known as female androgenetic alopecia is a common condition afflicting millions of women that can be cosmetically disrupting. Prompt diagnosis and treatment are essential for obtaining optimal outcome. This review addresses the clinical presentation of female pattern hair loss, its differential diagnosis and treatment modalities. A) Diffuse thinning of the crown region with preservation of the frontal hairline (Ludwig's type) B) The "Christmas tree pattern" where the thinning is wider in the frontal scalp giving the alopecic area a triangular shaped figure resembling a christmas tree. C) Thinning associated with bitemporal recession (Hamilton type). Generally, FPHL is not associated with elevated androgens. Less commonly females with FPHL may have other skin or general signs of hyperandrogenism such as hirsutism, acne, irregular menses, infertility, galactorrhea and insulin resistance. The most common endocrinological abnormality associated with FPHL is polycystic ovarian syndrome (PCOS). The most important diseases to consider in the differential diagnosis of FPHL include Chronic Telogen Effluvium (CTE), Permanent Alopecia after Chemotherapy (PAC), Alopecia Areata Incognito (AAI) and Frontal Fibrosing Alopecia (FFA). This review describes criteria for distinguishing these conditions from FPHL. The only approved treatment for FPHL, which is 2% topical Minoxidil, should be applied at the dosage of 1ml twice day for a minimum period of 12 months. This review will discuss off-label alternative modalities of treatment including 5-alfa reductase inhibitors, antiandrogens, estrogens, prostaglandin analogs, lasers, light treatments and hair transplantation.

The LS-STAG immersed boundary method for non-Newtonian flows in irregular geometries: flow of shear-thinning liquids between eccentric rotating cylinders

NASA Astrophysics Data System (ADS)

Botella, Olivier; Ait-Messaoud, Mazigh; Pertat, Adrien; Cheny, Yoann; Rigal, Claire

2015-04-01

This paper presents the extension of a well-established immersed boundary/cut-cell method, the LS-STAG method (Cheny and Botella in J Comput Phys 229:1043-1076, 2010), to non-Newtonian flow computations in 2D irregular geometries. One of the distinguished features of our IB method is to use level-set techniques in the cut-cells near the irregular boundary, where accurate discretization is of paramount importance for stability and accuracy of the computations. For this purpose, we present here an accurate discretization of the velocity gradients and shear rate in the cut-cells that fits elegantly in the framework of the velocity-pressure-stress staggered arrangement and the special quadratures developed previously for viscoelastic flows. After assessing the accuracy of the discretization on a benchmark solution for power-law fluids, the LS-STAG code is applied to the flow of various shear-thinning xanthan solutions in a wide-gap, non-coaxial, Taylor-Couette reactor for which rheological characterization, experimental flow measurements (PIV) and FLUENT simulations have recently been performed in our group. Our numerical investigation will give new insight on the flow patterns (onset, size and position of the recirculation zone) and will firmly correlate them to global flow properties such as shear-thinning index, generalized Reynolds number and torque ratio at the cylinders.

Adaptive Optics System with Deformable Composite Mirror and High Speed, Ultra-Compact Electronics

NASA Astrophysics Data System (ADS)

Chen, Peter C.; Knowles, G. J.; Shea, B. G.

2006-06-01

We report development of a novel adaptive optics system for optical astronomy. Key components are very thin Deformable Mirrors (DM) made of fiber reinforced polymer resins, subminiature PMN-PT actuators, and low power, high bandwidth electronics drive system with compact packaging and minimal wiring. By using specific formulations of fibers, resins, and laminate construction, we are able to fabricate mirror face sheets that are thin (< 2mm), have smooth surfaces and excellent optical shape. The mirrors are not astigmatic and do not develop surface irregularities when cooled. The actuators are small footprint multilayer PMN-PT ceramic devices with large stroke (2- 20 microns), high linearity, low hysteresis, low power, and flat frequency response to >2 KHz. By utilizing QorTek’s proprietary synthetic impendence power supply technology, all the power, control, and signal extraction for many hundreds to 1000s of actuators and sensors can be implemented on a single matrix controller printed circuit board co-mounted with the DM. The matrix controller, in turn requires only a single serial bus interface, thereby obviating the need for massive wiring harnesses. The technology can be scaled up to multi-meter aperture DMs with >100K actuators.

The Effect of Sunlight in Parenchyma Pith Cells Diameter of Manihot esculenta

NASA Astrophysics Data System (ADS)

Susanti, D.; Aziz, D. N.; Astuti, W.; Nuraeni, E.

2017-03-01

Sunlight is one of the factors that effect on the grow of a plant. Manihot esculenta is one of the plants that easily found in Indonesia because its role as staple food. The aim of this research is to know the correlation between sunlight the grow of parenchyma pith cells diameter of Manihot esculenta. Independent variable in this research is sunlight, and dependent variable is the parenchyma pith cells diameter of Manihot esculenta. Data was collected is in qualitative and quantitative form. Qualitative data gotten gained by morphology observation. The parenchyma pith cells of Manihot esculenta that is affected by sunlight in 1310 x 10 Lux, morphologically has hexagon, cell walls thick, solid state, and regular composition. Meanwhile, the parenchyma pith cells that has less sunlight (363 x 10 Lux) has a hexagon shape, thin cell walls thin, soft state, and irregular composition. Qualitative data suported by quantitative data. The size of parenchyma pith cells diameter that is affected by sunlight in 1310 x 10 Lux 96,4 µm. While, the stem parenchyma pith cells diameter empulur that has less sunlight (363 x 10 Lux) is 129,8 µm.

Swiveling Lathe Jaw Concept for Holding Irregular Pieces

NASA Technical Reports Server (NTRS)

David, J.

1966-01-01

Clamp holds irregularly shaped pieces in lathe chuck without damage and eliminates excessive time in selecting optimum mounting. Interchangeable jaws ride in standard jaw slots but swivel so that the jaw face bears evenly against the workpiece regardless of contour. The jaws can be used on both engine and turret lathes.

Clusters in irregular areas and lattices.

PubMed

Wieczorek, William F; Delmerico, Alan M; Rogerson, Peter A; Wong, David W S

2012-01-01

Geographic areas of different sizes and shapes of polygons that represent counts or rate data are often encountered in social, economic, health, and other information. Often political or census boundaries are used to define these areas because the information is available only for those geographies. Therefore, these types of boundaries are frequently used to define neighborhoods in spatial analyses using geographic information systems and related approaches such as multilevel models. When point data can be geocoded, it is possible to examine the impact of polygon shape on spatial statistical properties, such as clustering. We utilized point data (alcohol outlets) to examine the issue of polygon shape and size on visualization and statistical properties. The point data were allocated to regular lattices (hexagons and squares) and census areas for zip-code tabulation areas and tracts. The number of units in the lattices was set to be similar to the number of tract and zip-code areas. A spatial clustering statistic and visualization were used to assess the impact of polygon shape for zip- and tract-sized units. Results showed substantial similarities and notable differences across shape and size. The specific circumstances of a spatial analysis that aggregates points to polygons will determine the size and shape of the areal units to be used. The irregular polygons of census units may reflect underlying characteristics that could be missed by large regular lattices. Future research to examine the potential for using a combination of irregular polygons and regular lattices would be useful.

Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

PubMed Central

Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

2015-01-01

SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698

Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars.

PubMed

Abarca, J; Zaror, C; Monardes, H; Hermosilla, V; Muñoz, C; Cantin, M

2014-06-01

Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3-5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24-0.33 mm in maxillary first molars and between 0.25-0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully.

The effect of interpersonal rejection on attentional biases regarding thin-ideal and non-thin images: The moderating role of body weight- and shape-based self-worth.

PubMed

Rieger, Elizabeth; Dolan, Ashleigh; Thomas, Brittany; Bell, Jason

2017-09-01

Interpersonal dysfunction and weight/shape-based self-worth have been implicated as key constructs for eating disorders, although the relationship between these two concepts is under-researched. This study investigated the moderating role of weight/shape-based self-worth in terms of the impact of interpersonal rejection on attentional bias regarding thin-ideal and non-thin images. Participants were 94 females without an eating disorder, who were exposed to either interpersonal rejection or acceptance (using the Cyberball paradigm), and subsequently assessed in terms of their attentional biases regarding thin-ideal and non-thin images. Results revealed that weight/shape-based self-worth moderated the relationship between interpersonal rejection/acceptance and attentional biases for thin-ideal (but not non-thin) images. Specifically, participants with a greater tendency to base their self-worth on weight/shape demonstrated reduced avoidance of thin-ideal images when rejected relative to those who were accepted. The findings support the role of interpersonal rejection in eliciting attentional disturbances among those with higher body weight/shape-based self-worth. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effect of the Kind of Sands and Additions on the Mechanical Behaviour of S.C.C

NASA Astrophysics Data System (ADS)

Zeghichi, L.; Benghazi, Z.; Baali, L.

The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates. The effect of additions is also treated (blast furnace slag and lime stone) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

Visible light scattering properties of irregularly shaped silica microparticles using laser based laboratory simulations for remote sensing and medical applications

NASA Astrophysics Data System (ADS)

Boruah, Manash J.; Ahmed, Gazi A.

2018-01-01

Laser based experimental light scattering studies of irregularly shaped silica microparticles have been performed at three incident wavelengths 543.5 nm, 594.5 nm and 632.8 nm supported by laboratory based computations and 3D realistic simulations, using an indigenously fabricated light scattering setup. A comparative analysis of the computational and experimentally acquired results is done and a good agreement is found in the forward scattering lobes in all cases for each of the measured scattering parameters. This study also provides an efficient way of detecting and measuring particle size distribution for irregular micro- and nanoparticles and is highly applicable in remote sensing, atmospheric, astrophysical, and medical applications and also for finding potential health hazards in the form of inhalable and respirable small particulate matter.

Lattice Boltzmann simulations of settling behaviors of irregularly shaped particles

NASA Astrophysics Data System (ADS)

Zhang, Pei; Galindo-Torres, S. A.; Tang, Hongwu; Jin, Guangqiu; Scheuermann, A.; Li, Ling

2016-06-01

We investigated the settling dynamics of irregularly shaped particles in a still fluid under a wide range of conditions with Reynolds numbers Re varying between 1 and 2000, sphericity ϕ and circularity c both greater than 0.5, and Corey shape factor (CSF) less than 1. To simulate the particle settling process, a modified lattice Boltzmann model combined with a turbulence module was adopted. This model was first validated using experimental data for particles of spherical and cubic shapes. For irregularly shaped particles, two different types of settling behaviors were observed prior to particles reaching a steady state: accelerating and accelerating-decelerating, which could be distinguished by a critical CSF value of approximately 0.7. The settling dynamics were analyzed with a focus on the projected areas and angular velocities of particles. It was found that a minor change in the starting projected area, an indicator of the initial particle orientation, would not strongly affect the settling velocity for low Re. Periodic oscillations developed for all simulated particles when Re>100 . The amplitude of these oscillations increased with Re. However, the periods were not sensitive to Re. The critical Re that defined the transition between the steady and periodically oscillating behaviors depended on the inertia tensor. In particular, the maximum eigenvalue of the inertia tensor played a major role in signaling this transition in comparison to the intermediate and minimum eigenvalues.

Light scattering Q-space analysis of irregularly shaped particles

NASA Astrophysics Data System (ADS)

Heinson, Yuli W.; Maughan, Justin B.; Heinson, William R.; Chakrabarti, Amitabha; Sorensen, Christopher M.

2016-01-01

We report Q-space analysis of light scattering phase function data for irregularly shaped dust particles and of theoretical model output to describe them. This analysis involves plotting the scattered intensity versus the magnitude of the scattering wave vector q = (4π/λ)sin(θ/2), where λ is the optical wavelength and θ is the scattering angle, on a double-logarithmic plot. In q-space all the particle shapes studied display a scattering pattern which includes a q-independent forward scattering regime; a crossover, Guinier regime when q is near the inverse size; a power law regime; and an enhanced backscattering regime. Power law exponents show a quasi-universal functionality with the internal coupling parameter ρ'. The absolute value of the exponents start from 4 when ρ' < 1, the diffraction limit, and decreases as ρ' increases until a constant 1.75 ± 0.25 when ρ' ≳ 10. The diffraction limit exponent implies that despite their irregular structures, all the particles studied have mass and surface scaling dimensions of Dm = 3 and Ds = 2, respectively. This is different from fractal aggregates that have a power law equal to the fractal dimension Df because Df = Dm = Ds < 3. Spheres have Dm = 3 and Ds = 2 but do not show a single power law nor the same functionality with ρ'. The results presented here imply that Q-space analysis can differentiate between spheres and these two types of irregularly shaped particles. Furthermore, they are applicable to analysis of the contribution of aerosol radiative forcing to climate change and of aerosol remote sensing data.

Test functions for three-dimensional control-volume mixed finite-element methods on irregular grids

USGS Publications Warehouse

Naff, R.L.; Russell, T.F.; Wilson, J.D.; ,; ,; ,; ,; ,

2000-01-01

Numerical methods based on unstructured grids, with irregular cells, usually require discrete shape functions to approximate the distribution of quantities across cells. For control-volume mixed finite-element methods, vector shape functions are used to approximate the distribution of velocities across cells and vector test functions are used to minimize the error associated with the numerical approximation scheme. For a logically cubic mesh, the lowest-order shape functions are chosen in a natural way to conserve intercell fluxes that vary linearly in logical space. Vector test functions, while somewhat restricted by the mapping into the logical reference cube, admit a wider class of possibilities. Ideally, an error minimization procedure to select the test function from an acceptable class of candidates would be the best procedure. Lacking such a procedure, we first investigate the effect of possible test functions on the pressure distribution over the control volume; specifically, we look for test functions that allow for the elimination of intermediate pressures on cell faces. From these results, we select three forms for the test function for use in a control-volume mixed method code and subject them to an error analysis for different forms of grid irregularity; errors are reported in terms of the discrete L2 norm of the velocity error. Of these three forms, one appears to produce optimal results for most forms of grid irregularity.

Numerical study on 3D composite morphing actuators

NASA Astrophysics Data System (ADS)

Oishi, Kazuma; Saito, Makoto; Anandan, Nishita; Kadooka, Kevin; Taya, Minoru

2015-04-01

There are a number of actuators using the deformation of electroactive polymer (EAP), where fewer papers seem to have focused on the performance of 3D morphing actuators based on the analytical approach, due mainly to their complexity. The present paper introduces a numerical analysis approach on the large scale deformation and motion of a 3D half dome shaped actuator composed of thin soft membrane (passive material) and EAP strip actuators (EAP active coupon with electrodes on both surfaces), where the locations of the active EAP strips is a key parameter. Simulia/Abaqus Static and Implicit analysis code, whose main feature is the high precision contact analysis capability among structures, are used focusing on the whole process of the membrane to touch and wrap around the object. The unidirectional properties of the EAP coupon actuator are used as input data set for the material properties for the simulation and the verification of our numerical model, where the verification is made as compared to the existing 2D solution. The numerical results can demonstrate the whole deformation process of the membrane to wrap around not only smooth shaped objects like a sphere or an egg, but also irregularly shaped objects. A parametric study reveals the proper placement of the EAP coupon actuators, with the modification of the dome shape to induce the relevant large scale deformation. The numerical simulation for the 3D soft actuators shown in this paper could be applied to a wider range of soft 3D morphing actuators.

Accurate bulk density determination of irregularly shaped translucent and opaque aerogels

NASA Astrophysics Data System (ADS)

Petkov, M. P.; Jones, S. M.

2016-05-01

We present a volumetric method for accurate determination of bulk density of aerogels, calculated from extrapolated weight of the dry pure solid and volume estimates based on the Archimedes' principle of volume displacement, using packed 100 μm-sized monodispersed glass spheres as a "quasi-fluid" media. Hard particle packing theory is invoked to demonstrate the reproducibility of the apparent density of the quasi-fluid. Accuracy rivaling that of the refractive index method is demonstrated for both translucent and opaque aerogels with different absorptive properties, as well as for aerogels with regular and irregular shapes.

Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications

PubMed Central

Ambrósio, Jr, Renato; Correia, Fernando Faria; Lopes, Bernardo; Salomão, Marcella Q.; Luz, Allan; Dawson, Daniel G.; Elsheikh, Ahmed; Vinciguerra, Riccardo; Vinciguerra, Paolo; Roberts, Cynthia J.

2017-01-01

Background: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. Method: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. Conclusions: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy. PMID:28932334

Sensitivity analysis for axis rotation diagrid structural systems according to brace angle changes

NASA Astrophysics Data System (ADS)

Yang, Jae-Kwang; Li, Long-Yang; Park, Sung-Soo

2017-10-01

General regular shaped diagrid structures can express diverse shapes because braces are installed along the exterior faces of the structures and the structures have no columns. However, since irregular shaped structures have diverse variables, studies to assess behaviors resulting from various variables are continuously required to supplement the imperfections related to such variables. In the present study, materials elastic modulus and yield strength were selected as variables for strength that would be applied to diagrid structural systems in the form of Twisters among the irregular shaped buildings classified by Vollers and that affect the structural design of these structural systems. The purpose of this study is to conduct sensitivity analysis for axial rotation diagrid structural systems according to changes in brace angles in order to identify the design variables that have relatively larger effects and the tendencies of the sensitivity of the structures according to changes in brace angles and axial rotation angles.

Analysis of incidence of keratoconus in relatives of patients who underwent corneal transplant due to advanced keratoconus using the Orbscan II topographic graphs

NASA Astrophysics Data System (ADS)

López Olazagasti, Estela; Hernández y del Callejo, César E.; Ibarra-Galitzia, Jorge; Ramírez-Zavaleta, Gustavo; Tepichín, Eduardo

2011-10-01

Keratoconus is a corneal disease in which the cornea assumes a conical shape due to an irregular alteration of the internal structure of the corneal tissue and sometimes is progressive, especially in young people. Anatomically, the main signs of keratoconus are thinning of the cornea in its central or paracentral region, usually accompanied by an increase in this part of a high irregular astigmatism, with a consequent loss of vision. Its diagnosis requires a thorough study including the family history, a complete ophthalmologic examination and imaging studies. This diagnosis allows classifying the type of keratoconus, which allow determining options of management, with what it is possible to establish a visual prognosis of each eye. One of the indicators that help in the diagnosis of keratoconus is an inherited familiar propensity. The literature reports an incidence of keratoconus of 11%1 in first-degree relatives of patients with keratoconus. Results suggest an ethnic dependence, which implies that the knowledge of the tendency of keratoconus in the Mexican population is important. In this work, we present the preliminary results of the study realized to a group of relatives of patients who underwent corneal transplant by advanced keratoconus using Orbscan II topographic diagnosis, to determine the predisposition to Keratoconus in this group.e

Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors

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

Aghili Yajadda, Mir Massoud

2014-10-21

We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at highmore » voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300 K) at low and high DC bias voltages (0.001 mV–50 V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.« less

Female Pattern Hair Loss

PubMed Central

Herskovitz, Ingrid; Tosti, Antonella

2013-01-01

Context: Female pattern hair loss (FPHL) also known as female androgenetic alopecia is a common condition afflicting millions of women that can be cosmetically disrupting. Prompt diagnosis and treatment are essential for obtaining optimal outcome. This review addresses the clinical presentation of female pattern hair loss, its differential diagnosis and treatment modalities. Evidence Acquisition: A) Diffuse thinning of the crown region with preservation of the frontal hairline (Ludwig’s type) B) The “Christmas tree pattern” where the thinning is wider in the frontal scalp giving the alopecic area a triangular shaped figure resembling a christmas tree. C) Thinning associated with bitemporal recession (Hamilton type). Generally, FPHL is not associated with elevated androgens. Less commonly females with FPHL may have other skin or general signs of hyperandrogenism such as hirsutism, acne, irregular menses, infertility, galactorrhea and insulin resistance. The most common endocrinological abnormality associated with FPHL is polycystic ovarian syndrome (PCOS). Results: The most important diseases to consider in the differential diagnosis of FPHL include Chronic Telogen Effluvium (CTE), Permanent Alopecia after Chemotherapy (PAC), Alopecia Areata Incognito (AAI) and Frontal Fibrosing Alopecia (FFA). This review describes criteria for distinguishing these conditions from FPHL. Conclusions: The only approved treatment for FPHL, which is 2% topical Minoxidil, should be applied at the dosage of 1ml twice day for a minimum period of 12 months. This review will discuss off-label alternative modalities of treatment including 5-alfa reductase inhibitors, antiandrogens, estrogens, prostaglandin analogs, lasers, light treatments and hair transplantation. PMID:24719635

Controllable growth of shaped graphene domains by atmospheric pressure chemical vapour deposition

NASA Astrophysics Data System (ADS)

Fan, Lili; Li, Zhen; Li, Xiao; Wang, Kunlin; Zhong, Minlin; Wei, Jinquan; Wu, Dehai; Zhu, Hongwei

2011-12-01

Graphene domains in different shapes have been grown on copper substrates via atmospheric pressure chemical vapour deposition by controlling the growth process parameters. Under stabilized conditions, graphene domains tend to be six-fold symmetric hexagons under low flow rate methane with some domains in an irregular hexagonal shape. After further varying the growth duration, methane flow rate, and temperature, graphene domains have developed shapes from hexagon to shovel and dendrite. Two connecting modes, through overlap and merging of adjacent graphene domains, are proposed.Graphene domains in different shapes have been grown on copper substrates via atmospheric pressure chemical vapour deposition by controlling the growth process parameters. Under stabilized conditions, graphene domains tend to be six-fold symmetric hexagons under low flow rate methane with some domains in an irregular hexagonal shape. After further varying the growth duration, methane flow rate, and temperature, graphene domains have developed shapes from hexagon to shovel and dendrite. Two connecting modes, through overlap and merging of adjacent graphene domains, are proposed. Electronic supplementary information (ESI) available: Schematics of CVD setups for graphene growth, Raman spectra and SEM images. See DOI: 10.1039/c1nr11480h

Dynamic Reorganization of the Cytoskeleton during Apoptosis: The Two Coffins Hypothesis.

PubMed

Povea-Cabello, Suleva; Oropesa-Ávila, Manuel; de la Cruz-Ojeda, Patricia; Villanueva-Paz, Marina; de la Mata, Mario; Suárez-Rivero, Juan Miguel; Álvarez-Córdoba, Mónica; Villalón-García, Irene; Cotán, David; Ybot-González, Patricia; Sánchez-Alcázar, José A

2017-11-11

During apoptosis, cells undergo characteristic morphological changes in which the cytoskeleton plays an active role. The cytoskeleton rearrangements have been mainly attributed to actinomyosin ring contraction, while microtubule and intermediate filaments are depolymerized at early stages of apoptosis. However, recent results have shown that microtubules are reorganized during the execution phase of apoptosis forming an apoptotic microtubule network (AMN). Evidence suggests that AMN is required to maintain plasma membrane integrity and cell morphology during the execution phase of apoptosis. The new "two coffins" hypothesis proposes that both AMN and apoptotic cells can adopt two morphological patterns, round or irregular, which result from different cytoskeleton kinetic reorganization during the execution phase of apoptosis induced by genotoxic agents. In addition, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocyte responses. These findings suggest that knowing the type of apoptosis may be important to predict how fast apoptotic cells undergo secondary necrosis and the subsequent immune response. From a pathological point of view, round-shaped apoptosis can be seen as a physiological and controlled type of apoptosis, while irregular-shaped apoptosis can be considered as a pathological type of cell death closer to necrosis.

Dynamic Reorganization of the Cytoskeleton during Apoptosis: The Two Coffins Hypothesis

PubMed Central

Povea-Cabello, Suleva; Oropesa-Ávila, Manuel; de la Cruz-Ojeda, Patricia; Villanueva-Paz, Marina; de la Mata, Mario; Álvarez-Córdoba, Mónica; Villalón-García, Irene; Cotán, David; Ybot-González, Patricia

2017-01-01

During apoptosis, cells undergo characteristic morphological changes in which the cytoskeleton plays an active role. The cytoskeleton rearrangements have been mainly attributed to actinomyosin ring contraction, while microtubule and intermediate filaments are depolymerized at early stages of apoptosis. However, recent results have shown that microtubules are reorganized during the execution phase of apoptosis forming an apoptotic microtubule network (AMN). Evidence suggests that AMN is required to maintain plasma membrane integrity and cell morphology during the execution phase of apoptosis. The new “two coffins” hypothesis proposes that both AMN and apoptotic cells can adopt two morphological patterns, round or irregular, which result from different cytoskeleton kinetic reorganization during the execution phase of apoptosis induced by genotoxic agents. In addition, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocyte responses. These findings suggest that knowing the type of apoptosis may be important to predict how fast apoptotic cells undergo secondary necrosis and the subsequent immune response. From a pathological point of view, round-shaped apoptosis can be seen as a physiological and controlled type of apoptosis, while irregular-shaped apoptosis can be considered as a pathological type of cell death closer to necrosis. PMID:29137119

The normal squamocolumnar junction is circumferentially even and minimal irregularities are manifestations of gastroesophageal acid reflux.

PubMed

Guerrero Garcia Hall, Mats; Wenner, Jörgen; Öberg, Stefan

2017-03-01

The macroscopic appearance of the normal squamocolumnar junction (SCJ) is often described as serrated with short projections of columnar mucosa that extend into the esophagus. As studies of the normal SCJ are sparse, the aim of this study was to test the hypothesis that the normal SCJ is even and that irregularities are manifestations of acid reflux. Fifty asymptomatic subjects and 149 patients with symptoms suggestive of gastroesophageal reflux disease underwent endoscopy and 48-h pH monitoring with a pH electrode positioned immediately above the SCJ. The shape of the SCJ was assessed according to the Z-line appearance classification and correlated with clinical characteristics and the degree of esophageal acid exposure in the most distal esophagus. Even SCJs without irregularities were significantly more common in asymptomatic subjects compared with patients (50% versus 10%, p < .001) and were never found in patients with erosive esophagitis. The median degree of distal esophageal acid exposure in individuals with an even SCJ was within normal limits. With increasing degree of irregularity of the SCJ, the frequency and duration of reflux episodes, the degree of distal esophageal acid exposure, and the prevalence of abnormal acid exposure increased progressively and significantly. The shape of the normal SCJ is even and also minimal irregularities are a consequence of acid reflux, likely due to the formation of small areas of metaplastic columnar mucosa.

Automatic estimation of dynamics of ionospheric disturbances with 1–15 minute lifetimes as derived from ISTP SB RAS fast chirp-ionosonde data

NASA Astrophysics Data System (ADS)

Berngardt, Oleg; Bubnova, Tatyana; Podlesnyi, Aleksey

2018-03-01

We propose and test a method of analyzing ionograms of vertical ionospheric sounding, which is based on detecting deviations of the shape of an ionogram from its regular (averaged) shape. We interpret these deviations in terms of reflection from the electron density irregularities at heights corresponding to the effective height. We examine the irregularities thus discovered within the framework of a model of a localized uniformly moving irregularity, and determine their characteristic parameters: effective heights and observed vertical velocities. We analyze selected experimental data for three seasons (spring, winter, autumn) obtained nearby Irkutsk with a fast chirp ionosonde of ISTP SB RAS in 2013-2015. The analysis of six days of observations conducted in these seasons has shown that in the observed vertical drift of the irregularities there are two characteristic distributions: wide velocity distribution with nearly 0 m/s mean and with the standard deviation of ∼250 m/s and narrow distribution with nearly -160 m/s mean. The analysis has demonstrated the effectiveness of the proposed algorithm for the automatic analysis of vertical sounding data with high repetition rate.

Transformation of irregular shaped silver nanostructures into nanoparticles by under water pulsed laser melting

NASA Astrophysics Data System (ADS)

Yadavali, S.; Sandireddy, V. P.; Kalyanaraman, R.

2016-05-01

The ability to easily manufacture nanostructures with a desirable attribute, such as well-defined size and shape, especially from any given initial shapes or sizes of the material, will be helpful towards accelerating the use of nanomaterials in various applications. In this work we report the transformation of discontinuous irregular nanostructures (DIN) of silver metal by rapid heating under a bulk fluid layer. Ag films were changed into DIN by dewetting in air and subsequently heated by nanosecond laser pulses under water. Our findings show that the DIN first ripens into elongated structures and then breaks up into nanoparticles. From the dependence of this behavior on laser fluence we found that under water irradiation reduced the rate of ripening and also decreased the characteristic break-up length scale of the elongated structures. This latter result was qualitatively interpreted as arising from a Rayleigh-Plateau instability modified to yield significantly smaller length scales than the classical process due to pressure gradients arising from the rapid evaporation of water during laser melting. These results demonstrate that it is possible to fabricate a dense collection of monomodally sized Ag nanoparticles with significantly enhanced plasmonic quality starting from the irregular shaped materials. This can be beneficial towards transforming discontinuous Ag films into nanostructures with useful plasmonic properties, that are relevant for biosensing applications.

[MODEL ESTABLISHMENT, MRI AND PATHOLOGICAL FEATURES OF EARLY STEROID-INDUCED AVASCULAR NECROSIS OF FEMORAL HEAD IN RABBIT].

PubMed

Zhang, Liyan; Sun, Xin; Tian, Dan; Xu, Rui; Lei, Hao; Al, Jinhui; Zhao, Bo; Chen, Jiying; Chai, Wei; Ma, Shoucheng; Liu, Weijia; Shen, Siyuan

2015-10-01

To establish an rabbit model of early steroid-induced avascular necrosis of the femoral head (SANFH) and evaluate its validity with MRI and pathological examination. Twenty 6-month-old rabbits (weighing, 2-3 kg) were randomly divided into 2 groups (control group and model group), 10 rabbits in each group. Dexamethasone sodium phosphate solution (10 mg/kg) was injected into bilateral gluteus in model group, and the same amount of saline was injected in control group, every 3 days for 14 times. General observation was done after modelling. Osteonecrosis was verified by pathological observation and MRI findings at 6 weeks. After 6 weeks, rabbits did not show obvious changes in control group; increased hair removal, decreased food intake, and slight limp were observed in model group. The MRI results showed normal shape of the bilateral femoral head and no abnormal signals in control group; irregular shape of the bilateral femoral head and a slice of irregular abnormal signals were observed, and necrosis and cystolization of the subchondral bone and sparse changes of trabecular bone were shown in model group. General observation from coronal section of femoral head showed smooth red cartilage surface in control group; on the contrary, the cartilage surface of the femoral head became dull, thin even visible hemorrhage under articular cartilage and necrosis of the femoral head were observed. The histopathological examination indicated that trabecular bone of the femoral head in control group was massive, thick, and close and osteocytes in the bone lacunae had normal shapes. The osseous trabecular became thinner and broken; karyopyknosis of osteocytes and bone empty lacunae could be obviously seen in model. group. The rates of empty lacunae were 8.0% ± 0.5% in control group and 49.0% ± 0.3% in model group, showing significant difference (t = 21.940, P = 0.000). Establishing a model of early SANFH through injecting short-term, shock, and high dose of dexamethasone, and it can been evaluated effectively with MRI and pathological examination.

Shape and size distribution of chaos areas on Europa

NASA Astrophysics Data System (ADS)

Mikell, T.; Cox, R.

2008-12-01

Chaos terrain is ubiquitous on Europa's surface, but not randomly distributed. The global distribution of chaos areas shows a significant concentration between 30° N and S latitude, decreasing dramatically at higher latitudes. The low-latitude clustering is not an artifact of recognizability, as there is a greater proportion of images with high solar incidence angle (low light) at higher latitudes. Clustering is especially marked in context of the few but vast regional chaos tracts (>15,000 km2) that occupy a substantial proportion of the equatorial region: i.e. the low latitudes have not only greater numbers but much greater areal chaos coverage. Apex-antapex asymmetry is difficult to evaluate because the Galileo longitudinal coverage is so poor; but comparison of the image swaths that follow great circles across the leading and trailing hemispheres respectively shows greater numbers of chaos areas on the leading side. In spite of the equatorial location of a few vast chaos tracts, there is no apparent relationship between chaos area size and latitude. Chaos area outlines vary from smoothly circular to extremely jagged: the irregularity index ranges from 2- 270% (based on the ratio between measured chaos area perimeter and the circumference of a circle of equal area). There is a range of shapes in all size brackets, but smaller chaos areas on average have simpler, more equidimensional shapes, and edge complexity increases for larger chaos areas. Chaos areas of ~10 km equivalent circle diameter (ECD) have outlines that are 4-90% irregular, ones ~50 km ECD are 15-180% and those >100 km ECD are 35-270% irregular. In general, chaos areas with higher irregularity indices also have a higher raft:matrix ratio. These results, while preliminary, are consistent with experimental evidence suggesting an impact origin for some chaos terrain on Europa. In particular, the relationship between shape and size parallels the results of impact experiments into ice over water, in which lower-energy impacts produce small, circular bullet-holes with few or no rafts; and higher-energy impacts generate wide-field fragmentation of the ice, producing large and highly irregular openings with abundant floating crustal blocks.

Dissipation of ionospheric irregularities by wave-particle and collisional interactions

NASA Technical Reports Server (NTRS)

Bernhardt, P. A.; Pongratz, M. B.; Gray, S. P.; Thomsen, M. F.

1982-01-01

The nonlinear dissipation of plasma irregularities aligned parallel to an ambient magnetic field is studied numerically using a model which employs both wave-particle and collisional diffusion. A wave-particle diffusion coefficient derived from a local theory of the universal drift instability is used. This coefficient is effective in regions of nonzero plasma gradients and produces triangular-shaped irregularities with spectra which vary as f to the -4th, where f is the spatial frequency. Collisional diffusion acts rapidly on the vertices of the irregularities to reduce their amplitude. The simultaneous action of the two dissipative processes is more efficient than collisions acting alone. In this model, wave-particle diffusion mimics the forward cascade process of wave-wave coupling.

A database of body-only computer-generated pictures of women for body-image studies: Development and preliminary validation.

PubMed

Moussally, Joanna M; Rochat, Lucien; Posada, Andrés; Van der Linden, Martial

2017-02-01

The body-shape-related stimuli used in most body-image studies have several limitations (e.g., a lack of pilot validation procedures and the use of non-body-shape-related control/neutral stimuli). We therefore developed a database of 61 computer-generated body-only pictures of women, wherein bodies were methodically manipulated in terms of fatness versus thinness. Eighty-two young women assessed the pictures' attractiveness, beauty, harmony (valence ratings), and body shape (assessed on a thinness/fatness axis), providing normative data for valence and body shape ratings. First, stimuli manipulated for fatness versus thinness conveyed comparable emotional intensities regarding the valence and body shape ratings. Second, different subcategories of stimuli were obtained on the basis of variations in body shape and valence judgments. Fat and thin bodies were distributed into several subcategories depending on their valence ratings, and a subcategory containing stimuli that were neutral in terms of valence and body shape was identified. Interestingly, at a descriptive level, the thinness/fatness manipulations of the bodies were in a curvilinear relationship with the valence ratings: Thin bodies were not only judged as positive, but also as negative when their estimated body mass indexes (BMIs) decreased too much. Finally, convergent validity was assessed by exploring the impacts of body-image-related variables (BMI, thin-ideal internalization, and body dissatisfaction) on participants' judgments of the bodies. Valence judgments, but not body shape judgments, were influenced by the participants' levels of thin-ideal internalization and body dissatisfaction. Participants' BMIs did not significantly influence their judgments. Given these findings, this database contains relevant material that can be used in various fields, primarily for studies of body-image disturbance or eating disorders.

Influences of peers' and family members' body shapes on perception of body image and desire for thinness in Japanese female students.

PubMed

Mase, Tomoki; Ohara, Kumiko; Miyawaki, Chiemi; Kouda, Katsuyasu; Nakamura, Harunobu

2015-01-01

The present study investigated the influence of peers' and family members' body shapes on the perception of body image and desire for thinness in Japanese female students. The study included 342 female, Japanese university students between the ages of 18 years and 22 years. They completed an anonymous questionnaire, which included questions related to anthropometry and body perception. Eating behavior was assessed by the Japanese version of the Eating Attitude Test-26. Many students overestimated their body shape (81.2% of underweight students and 74.6% of normal students) and had a desire for thinness (41.0% of underweight students, 88.2% of normal students, and 100% of overweight students). One of the main reasons for the overestimation of their body shape was comparison with others. Participants who were interested in a friend's body shape were almost three times more likely to have a desire for thinness than those who were not interested in a female friend's body shape (odds ratio: 3.06, P=0.014). The results indicate a possibility that a female Japanese student's young female friends' body shapes, influences her desire for thinness or her perception of her own body shape.

Trace fossils and paleoenvironments of lower and middle Austin Chalk (upper Cretaceous), north-central Texas

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

Dawson, W.C.; Reaser, D.F.

Outcrops of lower and middle Austin Chalk in the vicinity of Cedar Hill and Waxahachie, Texas (designated site of the Superconducting Super Collider), are profusely bioturbated. The lower Austin (Coniacian) disconformably overlies the Eagle Ford Shale (Turonian) and consists of about 60 m of medium- to thick-bedded indurated chalk with thin intervening marls. The middle Austin (Santonian) is composed of about 65 m of thick-bedded marl containing thin beds of argillaceous chalk. Both chalk and marl units are moderately to intensely bioturbated. However, ichnofossils are more conspicuous in chalks where multiple episodes of burrowing are recognizable. Early formed burrows (indistinctmore » mottles) represent the initial softground Austin substrate. Later generations of well-preserved burrows record a post-compaction (dewatered) firmground substrate. No hardgrounds have been recognized. The abundance and diversity of ichnofossils in Austin strata are in marked contrast to the paucity of other megafauna, except large inoceramids. Planolites, Teichichnus, Thalassinoides, and Chondrites are the predominant ichnogenera in the lower Austin; these forms are superimposed on a background of nondiagnostic, irregularly shaped mottles. Some strata contain well-preserved J-, S-, T-, U-, Y-, and X-shaped traces having menicus fillings. These subhorizontal, endogenic, full-relief burrows are typically infilled with dark gray (pyritic) chalk. Locally, pyrite or Fe-oxide-filled vertical tubes are preserved. Many traces have been deformed by compaction. The middle Austin contains Planolites, Chondrites, Thalassinoides, Pseudobilobites, and both small- and large-diameter, sinuous, horizontal burrows. These ichnofossils are infilled with chalk or comminuted shells and are more resistant to weathering than the surrounding middle Austin marl. Intensely burrowed horizons occur in association with distinctive Fe-stained chalk beds.« less

"Reinventing" Techniques for the Estimation of the Area of Irregular Plane Figures: From the Eighteenth Century to the Modern Classroom

ERIC Educational Resources Information Center

Papadopoulos, Ioannis

2010-01-01

The issue of the area of irregular shapes is absent from the modern mathematical textbooks in elementary education in Greece. However, there exists a collection of books written for educational purposes by famous Greek scholars dating from the eighteenth century, which propose certain techniques concerning the estimation of the area of such…

49 CFR 393.136 - What are the rules for securing large boulders?

Code of Federal Regulations, 2011 CFR

2011-10-01

... adequately secured. (3) Rock which has been formed or cut to a shape and which provides a stable base for... blocking used to support the boulder. (e) Securement of a non-cubic shaped boulder—with a stable base. In... piece of natural, irregularly shaped rock weighing in excess of 5,000 kg (11,000 lb.) or with a volume...

Scattering of elastic waves from thin shapes in three dimensions using the composite boundary integral equation formulation

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

Liu, Y.; Rizzo, F.J.

1997-08-01

In this paper, the composite boundary integral equation (BIE) formulation is applied to scattering of elastic waves from thin shapes with small but {ital finite} thickness (open cracks or thin voids, thin inclusions, thin-layer interfaces, etc.), which are modeled with {ital two surfaces}. This composite BIE formulation, which is an extension of the Burton and Miller{close_quote}s formulation for acoustic waves, uses a linear combination of the conventional BIE and the hypersingular BIE. For thin shapes, the conventional BIE, as well as the hypersingular BIE, will degenerate (or nearly degenerate) if they are applied {ital individually} on the two surfaces. Themore » composite BIE formulation, however, will not degenerate for such problems, as demonstrated in this paper. Nearly singular and hypersingular integrals, which arise in problems involving thin shapes modeled with two surfaces, are transformed into sums of weakly singular integrals and nonsingular line integrals. Thus, no finer mesh is needed to compute these nearly singular integrals. Numerical examples of elastic waves scattered from penny-shaped cracks with varying openings are presented to demonstrate the effectiveness of the composite BIE formulation. {copyright} {ital 1997 Acoustical Society of America.}« less

Parameters assessment of the inductively-coupled circuit for wireless power transfer

NASA Astrophysics Data System (ADS)

Isaev, Yu N.; Vasileva, O. V.; Budko, A. A.; Lefebvre, S.

2017-02-01

In this paper, a wireless power transfer model through the example of inductively-coupled coils of irregular shape in software package COMSOL Multiphysics is studied. Circuit parameters, such as inductance, coil resistance and self-capacitance were defined through electromagnetic energy by the finite-element method. The study was carried out according to Helmholtz equation. Spatial distribution of current per unit depending on frequency and the coupling coefficient for analysis of resonant frequency and spatial distribution of the vector magnetic potential at different distances between coils were presented. The resulting algorithm allows simulating the wireless power transfer between the inductively coupled coils of irregular shape with the assessment of the optimal parameters.

Hubble Paints a Spattering of Blue

NASA Image and Video Library

2014-09-12

Far beyond the stars in the constellation of Leo (The Lion) is irregular galaxy IC 559. IC 559 is not your everyday galaxy. With its irregular shape and bright blue spattering of stars, it is a fascinating galactic anomaly. It may look like sparse cloud, but it is in fact full of gas and dust which is spawning new stars. Discovered in 1893, IC 559 lacks the symmetrical spiral appearance of some of its galactic peers and not does not conform to a regular shape. It is actually classified as a “type Sm” galaxy — an irregular galaxy with some evidence for a spiral structure. Irregular galaxies make up about a quarter of all known galaxies and do not fall into any of the regular classes of the Hubble sequence. Most of these uniquely shaped galaxies were not always so — IC 559 may have once been a conventional spiral galaxy that was then distorted and twisted by the gravity of a nearby cosmic companion. This image, captured by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3, combines a wide range of wavelengths spanning the ultraviolet, optical, and infrared parts of the spectrum. Image credit: ESA/Hubble, NASA, D. Calzetti (UMass) and the LEGUS Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

HF produced ionospheric electron density irregularities diagnosed by UHF radio star scintillations

NASA Technical Reports Server (NTRS)

Frey, A.; Gordon, W. E.

1982-01-01

Three observations of radio star intensity fluctuations at UHF are reported for HF ionospheric modification experiments carried out at the Arecibo Observatory. Two observations at 430 MHz and one at 1400 MHz suggest that the the thin phase screen theory is a good approximation to the observed power spectra. It is noted, however, that the theory has to be extended to include antenna filtering. This type of filtering is important for UHF radio star scintillations since the antenna usually has a narrow beamwidth. HF power densities of less than 37 microwatts/sq m incident on the ionosphere give rise to electron density irregularities larger than 13% of the ambient density (at 260 km) having scale sizes of approximately 510 m perpendicular to the geomagnetic field. The irregularities are found to form within 20-25 s after the HF power is turned on. The drift velocities of the irregularities can be estimated from the observed power spectra.

Effect of catalyst on deposition of vanadium oxide in plasma ambient

NASA Astrophysics Data System (ADS)

Singh, Megha; Kumar, Prabhat; Saini, Sujit K.; Reddy, G. B.

2018-05-01

In this paper, we have studied effect of catalyst (buffer layer) on structure, morphology, crystallinity, uniformity of nanostructured thin films deposited in nitrogen plasma ambient keeping all other process parameters constant. The process used for deposition is novel known as Plasma Assisted Sublimation Process (PASP). Samples were then studied using SEM, TEM, HRTEM, Raman spectroscopy. By structural analysis it was found out that samples deposited on Ni layer composed chiefly of α-V2O5 but minor amount of other phases were present in the sample. Samples deposited on Al catalyst layer revealed different phase of V2O5, where sample deposited on Ag was composed chiefly of VO2±x phase. Further analysis revealed that morphology of samples is also affected by catalyst. While samples deposited in Al and Ag layer tend to have reasonably defined geometry, sample deposited on Ni layer were irregular in shape and size. All the results well corroborate with each other.

Myopic keratomileusis by excimer laser on a lathe.

PubMed

Ganem, S; Aron-Rosa, D; Gross, M; Rosolen, S

1994-01-01

We designed an excimer laser keratomileusis delivery system to increase the regularity of the refractive cut surface and allow greater precision in the level and shape of the ablated zone. A parallel faced corneal disc was produced by microkeratectomy from six human eyes and surgical keratectomy in 12 beagle corneas. A 193-nanometer excimer laser that was used to project an oval beam onto the corneal disc was rotated on a flat surface to ensure overlapping of the ovally ablated areas between pulses. Electron microscopy of eye bank lenticules demonstrated a circular smooth regularly concave ablation zone. Histological examination of nine clear corneas confirmed thinning of the stroma without fibroblastic reaction and no epithelial hypertrophy. Mean preoperative corneal power of 43.15 +/- 2.18 decreased postoperatively to 33.61 +/- 2.34. The new technique of excimer laser keratomileusis has the advantage of a cut surface smoother and the clear zone is devoid of the stepwise concavity and irregularity seen in diaphragm based photoablation delivery systems.

Fine structure of the tapetum lucidum of the paca Cuniculus paca.

PubMed

Braekevelt, C R

1993-01-01

The tapetum lucidum of the paca or spotted cavy (Cuniculus paca) has been studied by light and electron microscopy. The reflective layer in this species is a tapetum cellulosum situated in the choroid of the superior fundus. Posteriorly, the tapetum is composed of several layers of ovoid to flattened cells while peripherally the tapetum gradually thins down and disappears. Within the tapetal cells most cell organelles are located near the nucleus. The dominant feature of these cells is, however, a large accumulation of electron-dense rodlets which show a variety of sizes, shapes and orientations. These rodlets are the reflective material of the tapetum, and energy dispersive studies indicate that they are rich in sulphur. The diameter and spacing of these irregular rodlets is too varied to be consistent with the principles of constructive interference, and the tapetum in the paca is probably capable of only diffuse reflectance. The retinal epithelium over the tapetum is nonpigmented while in non-tapetal locations it is normally pigmented.

Use of sonic tomography to detect and quantify wood decay in living trees1

PubMed Central

Gilbert, Gregory S.; Ballesteros, Javier O.; Barrios-Rodriguez, Cesar A.; Bonadies, Ernesto F.; Cedeño-Sánchez, Marjorie L.; Fossatti-Caballero, Nohely J.; Trejos-Rodríguez, Mariam M.; Pérez-Suñiga, José Moises; Holub-Young, Katharine S.; Henn, Laura A. W.; Thompson, Jennifer B.; García-López, Cesar G.; Romo, Amanda C.; Johnston, Daniel C.; Barrick, Pablo P.; Jordan, Fulvia A.; Hershcovich, Shiran; Russo, Natalie; Sánchez, Juan David; Fábrega, Juan Pablo; Lumpkin, Raleigh; McWilliams, Hunter A.; Chester, Kathleen N.; Burgos, Alana C.; Wong, E. Beatriz; Diab, Jonathan H.; Renteria, Sonia A.; Harrower, Jennifer T.; Hooton, Douglas A.; Glenn, Travis C.; Faircloth, Brant C.; Hubbell, Stephen P.

2016-01-01

Premise of the study: Field methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes. Methods and Results: Living trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness. Conclusions: Sonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees. PMID:28101433

Curve Appeal: Exploring Individual Differences in Preference for Curved Versus Angular Objects

PubMed Central

Cotter, Katherine N.; Bertamini, Marco; Palumbo, Letizia; Vartanian, Oshin

2017-01-01

A preference for smooth curvature, as opposed to angularity, is a well-established finding for lines, two-dimensional shapes, and complex objects, but little is known about individual differences. We used two-dimensional black-and-white shapes—randomly generated irregular polygons, and arrays of circles and hexagons—and measured many individual differences, including artistic expertise, personality, and cognitive style. As expected, people preferred curved over angular stimuli, and people’s degree of curvature preference correlated across the two sets of shapes. Multilevel models showed varying patterns of interaction between shape and individual differences. For the irregular polygons, people higher in artistic expertise or openness to experience showed a greater preference for curvature. This pattern was not evident for the arrays of circles and hexagons. We discuss the results in relation to the nature of the stimuli, and we conclude that individual differences do play a role in moderating the preference for smooth curvature. PMID:28491269

Selection of stationary phase particle geometry using X-ray computed tomography and computational fluid dynamics simulations.

PubMed

Schmidt, Irma; Minceva, Mirjana; Arlt, Wolfgang

2012-02-17

The X-ray computed tomography (CT) is used to determine local parameters related to the column packing homogeneity and hydrodynamics in columns packed with spherically and irregularly shaped particles of same size. The results showed that the variation of porosity and axial dispersion coefficient along the column axis is insignificant, compared to their radial distribution. The methodology of using the data attained by CT measurements to perform a CFD simulation of a batch separation of model binary mixtures, with different concentration and separation factors is demonstrated. The results of the CFD simulation study show that columns packed with spherically shaped particles provide higher yield in comparison to columns packed with irregularly shaped particles only below a certain value of the separation factor. The presented methodology can be used for selecting a suited packing material for a particular separation task. Copyright © 2012 Elsevier B.V. All rights reserved.

Using Fractal And Morphological Criteria For Automatic Classification Of Lung Diseases

NASA Astrophysics Data System (ADS)

Vehel, Jacques Levy

1989-11-01

Medical Images are difficult to analyze by means of classical image processing tools because they are very complex and irregular. Such shapes are obtained for instance in Nuclear Medecine with the spatial distribution of activity for organs such as lungs, liver, and heart. We have tried to apply two different theories to these signals: - Fractal Geometry deals with the analysis of complex irregular shapes which cannot well be described by the classical Euclidean geometry. - Integral Geometry treats sets globally and allows to introduce robust measures. We have computed three parameters on three kinds of Lung's SPECT images: normal, pulmonary embolism and chronic desease: - The commonly used fractal dimension (FD), that gives a measurement of the irregularity of the 3D shape. - The generalized lacunarity dimension (GLD), defined as the variance of the ratio of the local activity by the mean activity, which is only sensitive to the distribution and the size of gaps in the surface. - The Favard length that gives an approximation of the surface of a 3-D shape. The results show that each slice of the lung, considered as a 3D surface, is fractal and that the fractal dimension is the same for each slice and for the three kind of lungs; as for the lacunarity and Favard length, they are clearly different for normal lungs, pulmonary embolisms and chronic diseases. These results indicate that automatic classification of Lung's SPECT can be achieved, and that a quantitative measurement of the evolution of the disease could be made.

Reproducibility of image quality for moving objects using respiratory-gated computed tomography: a study using a phantom model

PubMed Central

Fukumitsu, Nobuyoshi; Ishida, Masaya; Terunuma, Toshiyuki; Mizumoto, Masashi; Hashimoto, Takayuki; Moritake, Takashi; Okumura, Toshiyuki; Sakae, Takeji; Tsuboi, Koji; Sakurai, Hideyuki

2012-01-01

To investigate the reproducibility of computed tomography (CT) imaging quality in respiratory-gated radiation treatment planning is essential in radiotherapy of movable tumors. Seven series of regular and six series of irregular respiratory motions were performed using a thorax dynamic phantom. For the regular respiratory motions, the respiratory cycle was changed from 2.5 to 4 s and the amplitude was changed from 4 to 10 mm. For the irregular respiratory motions, a cycle of 2.5 to 4 or an amplitude of 4 to 10 mm was added to the base data (i.e. 3.5-s cycle, 6-mm amplitude) every three cycles. Images of the object were acquired six times using respiratory-gated data acquisition. The volume of the object was calculated and the reproducibility of the volume was decided based on the variety. The registered image of the object was added and the reproducibility of the shape was decided based on the degree of overlap of objects. The variety in the volumes and shapes differed significantly as the respiratory cycle changed according to regular respiratory motions. In irregular respiratory motion, shape reproducibility was further inferior, and the percentage of overlap among the six images was 35.26% in the 2.5- and 3.5-s cycle mixed group. Amplitude changes did not produce significant differences in the variety of the volumes and shapes. Respiratory cycle changes reduced the reproducibility of the image quality in respiratory-gated CT. PMID:22966173

Flagellar motility of the pathogenic spirochetes

PubMed Central

Wolgemuth, Charles W.

2016-01-01

Bacterial pathogens are often classified by their toxicity and invasiveness. The invasiveness of a given bacterium is determined by how capable the bacterium is at invading a broad range of tissues in its host. Of mammalian pathogens, some of the most invasive come from a group of bacteria known as the spirochetes, which cause diseases such as syphilis, Lyme disease, relapsing fever and leptospirosis. Most of the spirochetes are characterized by their distinct shapes and unique motility. They are long, thin bacteria that can be shaped like flat-waves, helices, or have more irregular morphologies. Like many other bacteria, the spirochetes use long, helical appendages known as flagella to move; however, the spirochetes enclose their flagella in the periplasm, the narrow space between the inner and outer membranes. Rotation of the flagella in the periplasm causes the entire cell body to rotate and/or undulate. These deformations of the bacterium produce the force that drives the motility of these organisms, and it is this unique motility that likely allows these bacteria to be highly invasive in mammals. This review will describe the current state of knowledge on the motility and biophysics of these organisms and provide evidence on how this knowledge can inform our understanding of spirochetal diseases. PMID:26481969

Different Volumetric Measurement Methods for Pituitary Adenomas and Their Crucial Clinical Significance

PubMed Central

Chuang, Chi-Cheng; Lin, Shinn-Yn; Pai, Ping-Ching; Yan, Jiun-Lin; Toh, Cheng-Hong; Lee, Shih-Tseng; Wei, Kuo-Chen; Liu, Zhuo-Hao; Chen, Chung-Ming; Wang, Yu-Chi; Lee, Cheng-Chi

2017-01-01

Confirming the status of residual tumors is crucial. In stationary or spontaneous regression cases, early treatments are inappropriate. The long-used geometric calculation formula is 1/2 (length × width × height). However, it yields only rough estimates and is particularly unreliable for irregularly shaped masses. In our study, we attempted to propose a more accurate method. Between 2004 and 2014, 94 patients with pituitary tumors were enrolled in this retrospective study. All patients underwent transsphenoidal surgery and received magnetic resonance imaging (MRI). The pre- and postoperative volumes calculated using the traditional formula were termed A1 and A2, and those calculated using the proposed method were termed O1 and O2, respectively. Wilcoxon signed rank test revealed no significant difference between the A1 and O1 groups (P = 0.1810) but a significant difference between the A2 and O2 groups (P < 0.0001). Significant differences were present in the extent of resection (P < 0.0001), high-grade cavernous sinus invasion (P = 0.0312), and irregular shape (P = 0.0116). Volume is crucial in evaluating tumor status and determining treatment. Therefore, a more scientific method is especially useful when lesions are irregularly shaped or when treatment is determined exclusively based on the tumor volume. PMID:28098212

Risk Factors for the Rupture of Intracranial Aneurysms Using Computed Tomography Angiography.

PubMed

Wang, Guang-Xian; Wen, Li; Yang, Liu; Zhang, Qi-Chuang; Yin, Jin-Bo; Duan, Chun-Mei; Zhang, Dong

2018-02-01

To study the clinical and morphologic characteristics associated with risk factors for the rupture of intracranial aneurysms (IAs). A total of 1115 consecutive patients with 1282 IAs were reviewed from August 2011 to February 2016. The patients and IAs were divided into ruptured and unruptured groups. Based on the clinical and morphologic findings, the risk factors for IA rupture were assessed using statistical methods. Age, hypertension, diabetes mellitus, and cerebral atherosclerosis were associated with ruptured IAs. IAs located in the anterior cerebral artery, the anterior communicating artery, the posterior communicating artery, and the internal carotid artery were associated with ruptured IAs. Ruptures were also associated with arterial bifurcations, irregular aneurysm shapes, and all continuous data, except neck width. Binary logistic regression showed that IAs located at bifurcations (odds ratio [OR], 1.804), with irregular shapes (OR, 4.677), with high aspect ratios (ARs) (OR, 5.037) or with small mean diameters (MDs) (OR, 0.495) are more prone to rupture. Receiver operating characteristic analysis showed that the threshold values of the AR and MD were 1 and 3.70 mm, respectively. Morphologic characteristics, such as being located at bifurcations, being irregularly shaped, having a high AR (>1), and having a small MD (<3.70 mm), were better predictors of rupture. Copyright © 2017 Elsevier Inc. All rights reserved.

Influences of peers’ and family members’ body shapes on perception of body image and desire for thinness in Japanese female students

PubMed Central

Mase, Tomoki; Ohara, Kumiko; Miyawaki, Chiemi; Kouda, Katsuyasu; Nakamura, Harunobu

2015-01-01

Purpose The present study investigated the influence of peers’ and family members’ body shapes on the perception of body image and desire for thinness in Japanese female students. Methods The study included 342 female, Japanese university students between the ages of 18 years and 22 years. They completed an anonymous questionnaire, which included questions related to anthropometry and body perception. Eating behavior was assessed by the Japanese version of the Eating Attitude Test-26. Results Many students overestimated their body shape (81.2% of underweight students and 74.6% of normal students) and had a desire for thinness (41.0% of underweight students, 88.2% of normal students, and 100% of overweight students). One of the main reasons for the overestimation of their body shape was comparison with others. Participants who were interested in a friend’s body shape were almost three times more likely to have a desire for thinness than those who were not interested in a female friend’s body shape (odds ratio: 3.06, P=0.014). Conclusion The results indicate a possibility that a female Japanese student’s young female friends’ body shapes, influences her desire for thinness or her perception of her own body shape. PMID:26203283

Microstructure and Shape Memory Behavior of Ti-Nb Shape Memory Alloy Thin Film

NASA Astrophysics Data System (ADS)

Meng, X. L.; Sun, B.; Sun, J. Y.; Gao, Z. Y.; Cai, W.; Zhao, L. C.

2017-09-01

Ti-Nb shape memory alloy (SMA) thin film is a promising candidate applied as microactuator in biomedical field. In this study, the microstructure and shape memory behavior of Ti-Nb SMA thin films in different heat treatment conditions have been investigated. Fine ω phases embedded in the β phase matrix suppress the martensitic transformation of the films. As a result, the as-deposited and most of the annealed films consist of the β and α″ dual phases. The annealed Ti-Nb thin film shows excellent superelasticity effect when deformed above the reverse martensitic transformation temperature, that is 3.5% total recovery strain can be obtained when 4% pre-strain is loaded.

A Coherent Fiber for an Airborne Heterodyne Sensor.

DTIC Science & Technology

1982-04-01

17 4 TlBr /KRS-5 fiber showing irregular core shape . ....... ... 20 5 Enlargement of fiber cross section showing highly irregular core...21 6 TIBr/KRS-5 billet after extrusion ...... ............. 22 7 Side view of TlBr /KRS-5 fiber extruded at high...material. The composite billet is then extruded into fiber. Our composite billets were made of TlBr /KRS-5 and KRS-6/TlCl (clad/core). The extruded

Barium Cloud Test in Peru.

DTIC Science & Technology

1981-11-01

site. The irregularity would be measured by the AFWAL and AFGL equipped aircraft, the Jacamarca radar site, and receivers set at several Peruvian ground...The launch was made from Punta Lobos, Peru, a station of the Peruvian Space Commission (CONIDA). 1I AFWAL-TR-81-1178 SECTION II DESCRIPTION OF TEST...forming a football -shaped irregularity ion cloud (Figure 2). The clouds were then expected to drift eastwardly with the neutral ionospheric winds, crossing

Light Scattering Analysis of Irregularly Shaped Dust Particles: A Study Using 3-Dimensional Reconstructions from Focused Ion-Beam (FIB) Tomography and Q-Space Analysis

NASA Astrophysics Data System (ADS)

Ortiz-Montalvo, D. L.; Conny, J. M.

2017-12-01

We study the scattering properties of irregularly shaped ambient dust particles. The way in which they scatter and absorb light has implications for aerosol optical remote sensing and aerosol radiative forcing applications. However, understanding light scattering and absorption by non-spherical particles can be very challenging. We used focused ion-beam scanning electron microscopy and energy-dispersive x-ray spectroscopy (FIB-SEM-EDS) to reconstruct three-dimensional (3-D) configurations of dust particles collected from urban and Asian sources. The 3-D reconstructions were then used in a discrete dipole approximation method (DDA) to determine their scattering properties for a range of shapes, sizes, and refractive indices. Scattering properties where obtained using actual-shapes of the particles, as well as, (theoretical) equivalently-sized geometrical shapes like spheres, ellipsoids, cubes, rectangular prisms, and tetrahedrons. We use Q-space analysis to interpret the angular distribution of the scattered light obtained for each particle. Q-space analysis has been recently used to distinguish scattering by particles of different shapes, and it involves plotting the scattered intensity versus the scattering wave vector (q or qR) on a log-log scale, where q = 2ksin(θ/2), k = 2π/λ, and R = particle effective radius. Results from a limited number of particles show that when Q-space analysis is applied, common patterns appear that agree with previous Q-space studies done on ice crystals and other irregularly shaped particles. More specifically, we found similar Q-space regimes including a forward scattering regime of constant intensity when qR < 1, followed by the Guinier regime when qR ≈ 1, which is then followed by a complex power law regime with a -3 slope regime, a transition regime, and then a -4 slope regime. Currently, Q-space comparisons between actual- and geometric shapes are underway with the objective of determining which geometric shape best represents the angular distribution and magnitude of the scattered light. Current work also focuses on the effects of the imaginary part of the refractive index on the light scattering of our dust particles.

Effects of Explosions in Underground Magazines

DTIC Science & Technology

1989-10-01

Kayenta sandstone near Grand Junction, CO. Core samples indicated a relatively uniform rock with thin, horizontal, irregularly spaced, clay seams (Swift...Mechanical Properties of a Kayenta Sandstone from the Mixed Company Site," DNA 3683F, July 1975, Physics International Company, San Leandro, CA. 33

Management of irregular astigmatism.

PubMed

Goggin, M; Alpins, N; Schmid, L M

2000-08-01

Using a liberal definition of corneal irregularity, modern videokeratoscopy may define approximately 40% of normal corneas with a toric refractive error as possessing primary irregular astigmatism. The causes of secondary forms of irregular astigmatism include corneal surgery, trauma, dystrophies, and infections. Internal refractive surface and media irregularity or noncorneal astigmatism (ocular residual astigmatism) contribute to irregular astigmatism of the entire refractive path of which crystaline lenticular astigmatism is usually the principal contributing component. Treatment options have increased in recent years, particularly, though not exclusively, through the advent of tailored corneal excimer laser ablations. However, discussion continues concerning the systematic approach necessary to enable treatment to achieve an optimal optical surface for the eye. Discussion also continues as to what constitutes the optimal corneal shape. Some refractive procedures may increase higher order aberrations in the attempt to neutralize refractive astigmatism. The way to further refinement of the commonly performed refractive techniques will ultimately lie in the integrated inclusion of a trio of technologies: topographic analysis of the corneal surface, wavefront analysis of ocular refractive aberrations, and vector planning to enable the appropriate balance in emphasis between these two diagnostic modalities. For the uncommon, irregularly roughened corneas, the ablatable polymer techniques show some promise.

An exterior Poisson solver using fast direct methods and boundary integral equations with applications to nonlinear potential flow

NASA Technical Reports Server (NTRS)

Young, D. P.; Woo, A. C.; Bussoletti, J. E.; Johnson, F. T.

1986-01-01

A general method is developed combining fast direct methods and boundary integral equation methods to solve Poisson's equation on irregular exterior regions. The method requires O(N log N) operations where N is the number of grid points. Error estimates are given that hold for regions with corners and other boundary irregularities. Computational results are given in the context of computational aerodynamics for a two-dimensional lifting airfoil. Solutions of boundary integral equations for lifting and nonlifting aerodynamic configurations using preconditioned conjugate gradient are examined for varying degrees of thinness.

Three-Dimensional Visualization and Imaging of the Entry Tear and Intimal Flap of Aortic Dissection Using CT Virtual Intravascular Endoscopy

PubMed Central

Li, Gang; Ma, Xiangxing; Wang, Qing; Yu, Dexin

2016-01-01

Aims Conventional computed tomography (CT) approaches provides limited visualization of the entire endoluminal changes of aortic dissection (AD), which is essential for its treatment. As an important supplement, three-dimensional CT virtual intravascular endoscopy (VIE) can show relevant details. This study aims to determine the value of VIE in displaying the entry tear and intimal flap of AD. Methods and Results Among 127 consecutive symptomatic patients with suspected AD who underwent CT angiography (CTA), 84 subjects were confirmed to have AD and were included in the study. Conventional CT and VIE images were observed and evaluated. From the 92 entry tears revealed via conventional CT, 88 (95.7%) tears appeared on VIE with round (n = 26), slit-shaped (n = 9), or irregular (n = 53) shapes, whereas the intimal flaps were sheetlike (n = 34), tubular (n = 34), wavelike (n = 13), or irregular (n = 7) in shape. The VIE also showed the spatial relationship between the torn flap and adjacent structures. Among 58 entry tears with multiple-line type flap shown on conventional CT, 41 (70.7%) appeared with an irregular shape on VIE, whereas among 30 tears with single-line type flap, 17 (56.7%) appeared as round or slit-shaped on VIE. These results demonstrated a significant difference (P < 0.05). The poor display of tears on VIE was related to the low CT attenuation values in lumen or in neighboring artifacts (P < 0.01). Conclusion CT VIE presents the complete configurations and details of the intimal tears and flaps of AD better than conventional CT approaches. Accordingly, it should be recommended as a necessary assessment tool for endovascular therapy and as part of strategy planning in pre-surgical patients. PMID:27760170

Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects

NASA Astrophysics Data System (ADS)

Ye, Zhou; Nain, Amrinder S.; Behkam, Bahareh

2016-06-01

Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features.Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features. Electronic supplementary information (ESI) available: SWAN lithography on silicon; comparison of SWAN lithography and state-of-the-art nanopatterning methods; replica molding using SWAN lithography fabricated template; PDMS nanofluidic device, gold nanopattern characterization. See DOI: 10.1039/c6nr03323g

The occultation of Kappa Geminorum by Eros. [stellar occultation observed for asteroid size and shape

NASA Technical Reports Server (NTRS)

Oleary, B.; Marsden, B. G.; Dragon, R.; Hauser, E.; Mcgrath, M.; Backus, P.; Robkoff, H.

1976-01-01

The paper discusses predictions and observations of the occultation of Kappa Gem by (433) Eros on January 24, 1975. Several positive and negative observations made in western New England are described. Local circumstances for the occultation are reconstructed, and the size and shape of Eros are determined analytically as well as graphically. The calculations yield two extremes for the cross section: a circle 23 km in diameter or a somewhat irregular figure 20 km by 6 or 7 km. Arguments based on the expected albedo of the asteroid suggest that the circle should be warped into an ellipse 21 by 13 km or that the irregular figure might be one component of a dumbbell-like profile.

The inter-rater reliability of estimating the size of burns from various burn area chart drawings.

PubMed

Wachtel, T L; Berry, C C; Wachtel, E E; Frank, H A

2000-03-01

The accuracy and variability of burn size calculations using four Lund and Browder charts currently in clinical use and two Rule of Nine's diagrams were evaluated. The study showed that variability in estimation increased with burn size initially, plateaued in large burns and then decreased slightly in extensive burns. The Rule of Nine's technique often overestimates the burn size and is more variable, but can be performed somewhat faster than the Lund and Browder method. More burn experience leads to less variability in burn area chart drawing estimates. Irregularly shaped burns and burns on the trunk and thighs had greater variability than less irregularly shaped burns or burns on more defined anatomical parts of the body.

Tree shadow patterns and illumination measurements with clearcut strips and irregular openings in a true fir forest

Treesearch

Donald T. Gordon

1968-01-01

Daily progression of shadows cast by red and white fir trees in forest stand openings is illustrated by vertical aerial photographs made on the summer solstice at 2-hour intervals from 7 a.m. to 5 p.m. The aerial photos show shade patterns in three irregularly - shaped, natural stand openings and two different widths (3-chains and 5-chains) of clearcut strips....

Dose calculation for electron therapy using an improved LBR method.

PubMed

Gebreamlak, Wondesen T; Tedeschi, David J; Alkhatib, Hassaan A

2013-07-01

To calculate the percentage depth dose (PDD) of any irregularly shaped electron beam using a modified lateral build-up ratio (LBR) method. Percentage depth dose curves were measured using 6, 9, 12, and 15 MeV electron beam energies for applicator cone sizes of 6 × 6, 10 × 10, 14 × 14, and 20 × 20 cm(2). Circular cutouts for each cone were prepared from 2.0 cm diameter to the maximum possible size for each cone. In addition, three irregular cutouts were prepared. The LBR for each circular cutout was calculated from the measured PDD curve using the open field of the 14 × 14 cm(2) cone as the reference field. Using the LBR values and the radius of the circular cutouts, the corresponding lateral spread parameter [σR(z)] of the electron shower was calculated. Unlike the commonly accepted assumption that σR(z) is independent of cutout size, it is shown that its value increases linearly with circular cutout size (R). Using this characteristic of the lateral spread parameter, the PDD curves of irregularly shaped cutouts were calculated. Finally, the calculated PDD curves were compared with measured PDD curves. In this research, it is shown that the lateral spread parameter σR(z) increases with cutout size. For radii of circular cutout sizes up to the equilibrium range of the electron beam, the increase of σR(z) with the cutout size is linear. The percentage difference of the calculated PDD curve from the measured PDD data for irregularly shaped cutouts was under 1.0% in the region between the surface and therapeutic range of the electron beam. Similar results were obtained for four electron beam energies (6, 9, 12, and 15 MeV).

Matrix cracking with irregular fracture fronts as observed in fiber reinforced ceramic composites

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

Hu, K.X.; Yeh, C.P.; Wyatt, K.W.

1998-01-01

As a result of matrix cracking in fiber reinforced composites, fracture planforms assume a wide variation of profiles due to the fact that fiber bridging strongly affects the behavior of local crack fronts. This observation raises the question on the legitimacy of commonly used penny-shaped crack solutions when applied to fiber reinforced composites. Accordingly, investigation of the effects of fracture front profiles on mechanical responses is the thrust of this paper. The authors start with the solution of a penny-shaped crack in a unidirectional, fiber reinforced composite, which demonstrates necessity of considering wavy fracture fronts in fiber reinforced composites. Amore » theoretical framework for fiber reinforced composites with irregular fracture fronts due to matrix cracking is then established via a micromechanics model. The difference between small crack-size matrix cracking and large crack-size matrix cracking is investigated in detail. It is shown that the bridging effect is insignificant when matrix crack size is small and solution of effective property are obtained using Mori-Tanaka`s method by treating cracks and reinforcing fibers as distinct, but interacting phases. When the crack size becomes large, the bridging effects has to be taken into consideration. With bridging tractions obtained in consistency with the micromechanics solution, and corresponding crack energy backed out, the effective properties are obtained through a modification of standard Mori-Tanaka`s treatment of multiphase composites. Analytical solutions show that the generalization of a crack density of a penny-shaped planform is insufficient in describing the effective responses of fiber-reinforced composites with matrix cracking. Approximate solutions that account for the effects of the irregularity of crack planforms are given in closed forms for several irregular crack planforms, including cracks of cross rectangle, polygon and rhombus.« less

Fabrication of a Bioactive, PCL-based "Self-fitting" Shape Memory Polymer Scaffold.

PubMed

Nail, Lindsay N; Zhang, Dawei; Reinhard, Jessica L; Grunlan, Melissa A

2015-10-23

Tissue engineering has been explored as an alternative strategy for the treatment of critical-sized cranio-maxillofacial (CMF) bone defects. Essential to the success of this approach is a scaffold that is able to conformally fit within an irregular defect while also having the requisite biodegradability, pore interconnectivity and bioactivity. By nature of their shape recovery and fixity properties, shape memory polymer (SMP) scaffolds could achieve defect "self-fitting." In this way, following exposure to warm saline (~60 ºC), the SMP scaffold would become malleable, permitting it to be hand-pressed into an irregular defect. Subsequent cooling (~37 ºC) would return the scaffold to its relatively rigid state within the defect. To meet these requirements, this protocol describes the preparation of SMP scaffolds prepared via the photochemical cure of biodegradable polycaprolactone diacrylate (PCL-DA) using a solvent-casting particulate-leaching (SCPL) method. A fused salt template is utilized to achieve pore interconnectivity. To realize bioactivity, a polydopamine coating is applied to the surface of the scaffold pore walls. Characterization of self-fitting and shape memory behaviors, pore interconnectivity and in vitro bioactivity are also described.

On the interpolation of light-scattering responses from irregularly shaped particles

NASA Astrophysics Data System (ADS)

Videen, Gorden; Zubko, Evgenij; Arnold, Jessica A.; MacCall, Benjamin; Weinberger, Alycia J.; Shkuratov, Yuriy; Muñoz, Olga

2018-05-01

Common particle characteristics needed for many applications may include size, eccentricity, porosity and refractive index. Determining such characteristics from scattered light is a primary goal of remote sensing. For other applications, like differentiating a hazardous particle from the natural background, information about higher fidelity particle characteristics may be required, including specific shape or chemical composition. While a complete characterization of a particle system from its scattered light through the inversion process remains unachievable, great strides have been made in providing information in the form of constraints on particle characteristics. Recent advances have been made in quantifying the characteristics of polydispersions of irregularly shaped particles by making comparisons of the light-scattering signals from model simulant particles. We show that when the refractive index is changed, the light-scattering characteristics from polydispersions of such particles behave monotonically over relatively large parameter ranges compared with those of monodisperse distributions of particles having regular shapes, like spheres, spheroids, etc. This allows for their properties to be interpolated, which results in a significant reduction of the computational load when performing inversions.

Automatic tracking of arbitrarily shaped implanted markers in kilovoltage projection images: A feasibility study

PubMed Central

Regmi, Rajesh; Lovelock, D. Michael; Hunt, Margie; Zhang, Pengpeng; Pham, Hai; Xiong, Jianping; Yorke, Ellen D.; Goodman, Karyn A.; Rimner, Andreas; Mostafavi, Hassan; Mageras, Gig S.

2014-01-01

Purpose: Certain types of commonly used fiducial markers take on irregular shapes upon implantation in soft tissue. This poses a challenge for methods that assume a predefined shape of markers when automatically tracking such markers in kilovoltage (kV) radiographs. The authors have developed a method of automatically tracking regularly and irregularly shaped markers using kV projection images and assessed its potential for detecting intrafractional target motion during rotational treatment. Methods: Template-based matching used a normalized cross-correlation with simplex minimization. Templates were created from computed tomography (CT) images for phantom studies and from end-expiration breath-hold planning CT for patient studies. The kV images were processed using a Sobel filter to enhance marker visibility. To correct for changes in intermarker relative positions between simulation and treatment that can introduce errors in automatic matching, marker offsets in three dimensions were manually determined from an approximately orthogonal pair of kV images. Two studies in anthropomorphic phantom were carried out, one using a gold cylindrical marker representing regular shape, another using a Visicoil marker representing irregular shape. Automatic matching of templates to cone beam CT (CBCT) projection images was performed to known marker positions in phantom. In patient data, automatic matching was compared to manual matching as an approximate ground truth. Positional discrepancy between automatic and manual matching of less than 2 mm was assumed as the criterion for successful tracking. Tracking success rates were examined in kV projection images from 22 CBCT scans of four pancreas, six gastroesophageal junction, and one lung cancer patients. Each patient had at least one irregularly shaped radiopaque marker implanted in or near the tumor. In addition, automatic tracking was tested in intrafraction kV images of three lung cancer patients with irregularly shaped markers during 11 volumetric modulated arc treatments. Purpose-built software developed at our institution was used to create marker templates and track the markers embedded in kV images. Results: Phantom studies showed mean ± standard deviation measurement uncertainty of automatic registration to be 0.14 ± 0.07 mm and 0.17 ± 0.08 mm for Visicoil and gold cylindrical markers, respectively. The mean success rate of automatic tracking with CBCT projections (11 frames per second, fps) of pancreas, gastroesophageal junction, and lung cancer patients was 100%, 99.1% (range 98%–100%), and 100%, respectively. With intrafraction images (approx. 0.2 fps) of lung cancer patients, the success rate was 98.2% (range 97%–100%), and 94.3% (range 93%–97%) using templates from 1.25 mm and 2.5 mm slice spacing CT scans, respectively. Correction of intermarker relative position was found to improve the success rate in two out of eight patients analyzed. Conclusions: The proposed method can track arbitrary marker shapes in kV images using templates generated from a breath-hold CT acquired at simulation. The studies indicate its feasibility for tracking tumor motion during rotational treatment. Investigation of the causes of misregistration suggests that its rate of incidence can be reduced with higher frequency of image acquisition, templates made from smaller CT slice spacing, and correction of changes in intermarker relative positions when they occur. PMID:24989384

Automatic tracking of arbitrarily shaped implanted markers in kilovoltage projection images: A feasibility study

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

Regmi, Rajesh; Lovelock, D. Michael; Hunt, Margie

Purpose: Certain types of commonly used fiducial markers take on irregular shapes upon implantation in soft tissue. This poses a challenge for methods that assume a predefined shape of markers when automatically tracking such markers in kilovoltage (kV) radiographs. The authors have developed a method of automatically tracking regularly and irregularly shaped markers using kV projection images and assessed its potential for detecting intrafractional target motion during rotational treatment. Methods: Template-based matching used a normalized cross-correlation with simplex minimization. Templates were created from computed tomography (CT) images for phantom studies and from end-expiration breath-hold planning CT for patient studies. Themore » kV images were processed using a Sobel filter to enhance marker visibility. To correct for changes in intermarker relative positions between simulation and treatment that can introduce errors in automatic matching, marker offsets in three dimensions were manually determined from an approximately orthogonal pair of kV images. Two studies in anthropomorphic phantom were carried out, one using a gold cylindrical marker representing regular shape, another using a Visicoil marker representing irregular shape. Automatic matching of templates to cone beam CT (CBCT) projection images was performed to known marker positions in phantom. In patient data, automatic matching was compared to manual matching as an approximate ground truth. Positional discrepancy between automatic and manual matching of less than 2 mm was assumed as the criterion for successful tracking. Tracking success rates were examined in kV projection images from 22 CBCT scans of four pancreas, six gastroesophageal junction, and one lung cancer patients. Each patient had at least one irregularly shaped radiopaque marker implanted in or near the tumor. In addition, automatic tracking was tested in intrafraction kV images of three lung cancer patients with irregularly shaped markers during 11 volumetric modulated arc treatments. Purpose-built software developed at our institution was used to create marker templates and track the markers embedded in kV images. Results: Phantom studies showed mean ± standard deviation measurement uncertainty of automatic registration to be 0.14 ± 0.07 mm and 0.17 ± 0.08 mm for Visicoil and gold cylindrical markers, respectively. The mean success rate of automatic tracking with CBCT projections (11 frames per second, fps) of pancreas, gastroesophageal junction, and lung cancer patients was 100%, 99.1% (range 98%–100%), and 100%, respectively. With intrafraction images (approx. 0.2 fps) of lung cancer patients, the success rate was 98.2% (range 97%–100%), and 94.3% (range 93%–97%) using templates from 1.25 mm and 2.5 mm slice spacing CT scans, respectively. Correction of intermarker relative position was found to improve the success rate in two out of eight patients analyzed. Conclusions: The proposed method can track arbitrary marker shapes in kV images using templates generated from a breath-hold CT acquired at simulation. The studies indicate its feasibility for tracking tumor motion during rotational treatment. Investigation of the causes of misregistration suggests that its rate of incidence can be reduced with higher frequency of image acquisition, templates made from smaller CT slice spacing, and correction of changes in intermarker relative positions when they occur.« less

Preparation of Cotton-Wool-Like Poly(lactic acid)-Based Composites Consisting of Core-Shell-Type Fibers

PubMed Central

Wang, Jian; Zhou, Pin; Obata, Akiko; Jones, Julian R.; Kasuga, Toshihiro

2015-01-01

In previous works, we reported the fabrication of cotton-wool-like composites consisting of siloxane-doped vaterite and poly(l-lactic acid) (SiVPCs). Various irregularly shaped bone voids can be filled with the composite, which effectively supplies calcium and silicate ions, enhancing the bone formation by stimulating the cells. The composites, however, were brittle and showed an initial burst release of ions. In the present work, to improve the mechanical flexibility and ion release, the composite fiber was coated with a soft, thin layer consisting of poly(d,l-lactic-co-glycolic acid) (PLGA). A coaxial electrospinning technique was used to prepare a cotton-wool-like material comprising “core-shell”-type fibers with a diameter of ~12 µm. The fibers, which consisted of SiVPC coated with a ~2-µm-thick PLGA layer, were mechanically flexible; even under a uniaxial compressive load of 1.5 kPa, the cotton-wool-like material did not exhibit fracture of the fibers and, after removing the load, showed a ~60% recovery. In Tris buffer solution, the initial burst release of calcium and silicate ions from the “core-shell”-type fibers was effectively controlled, and the ions were slowly released after one day. Thus, the mechanical flexibility and ion-release behavior of the composites were drastically improved by the thin PLGA coating. PMID:28793691

Volume Quantification of Acute Infratentorial Hemorrhage with Computed Tomography: Validation of the Formula 1/2ABC and 2/3SH

PubMed Central

Zhang, Yunyun; Yan, Jing; Fu, Yi; Chen, Shengdi

2013-01-01

Objective To compare the accuracy of formula 1/2ABC with 2/3SH on volume estimation for hypertensive infratentorial hematoma. Methods One hundred and forty-seven CT scans diagnosed as hypertensive infratentorial hemorrhage were reviewed. Based on the shape, hematomas were categorized as regular or irregular. Multilobular was defined as a special shape of irregular. Hematoma volume was calculated employing computer-assisted volumetric analysis (CAVA), 1/2ABC and 2/3SH, respectively. Results The correlation coefficients between 1/2ABC (or 2/3SH) and CAVA were greater than 0.900 in all subgroups. There were neither significant differences in absolute values of volume deviation nor percentage deviation between 1/2ABC and 2/3SH for regular hemorrhage (P>0.05). While for cerebellar, brainstem and irregular hemorrhages, the absolute values of volume deviation and percentage deviation by formula 1/2ABC were greater than 2/3SH (P<0.05). 1/2ABC and 2/3SH underestimated hematoma volume each by 10% and 5% for cerebellar hemorrhage, 14% and 9% for brainstem hemorrhage, 19% and 16% for regular hemorrhage, 9% and 3% for irregular hemorrhage, respectively. In addition, for the multilobular hemorrhage, 1/2ABC underestimated the volume by 9% while 2/3SH overestimated it by 2%. Conclusions For regular hemorrhage volume calculation, the accuracy of 2/3SH is similar to 1/2ABC. While for cerebellar, brainstem or irregular hemorrhages (including multilobular), 2/3SH is more accurate than 1/2ABC. PMID:23638025

Identification and characterisation of individual Fractures in 3D fracture-network of shale reservoir rocks from microtomography

NASA Astrophysics Data System (ADS)

Qi, C.; Liu, J.

2017-12-01

Fractures are essential for unconventional hydrocarbon production. However, the observation of fractures in three-dimensional (3D) space is very difficult except using microtomography to obtain 3D fracture structures at micro-scales. Twelve shale samples taken from a specimen are analyzed in this study: six of them were isobarically and five were isothermally processed in experiments of simulating hydrocarbon generation and expulsion and one is unprocessed. The resolutions of microtomographic images are in the range from 5.83 to 9.12 μm. Fractures developed in different complexities: some samples have mostly parallel fractures, some have major parallel fractures plus irregular fractures forming crack-network and some samples have fully intersected fractures of various directions. To identify individual fractures in 3D network is crucial for the characterization of fractures and it needs to separate each fractures or disconnect intersections of fractures. For those samples with fewer intersections, it is not difficult to disconnect intersections manually slice by slice using Avizo®. For those samples with complex intersections, it is impractical to process manually. A patented method and corresponding programs are used to separate, identify and characterize individual fractures. By procedures of filtering, smoothing, thinning, separating and combining, intersected cracks are separated, the segments of a broken elongated cracks are identified as one crack, and the thinned thickness is restored, finally the shape, orientation and dimensions of individual fractures are characterized. Our results show that: 1) relatively large fractures are very thin, showing typical fracture morphology, while small fractures may have various shapes; 2) isothermal processed samples have stronger anisotropy, which implies that the fractures in isothermal series are thinner or flatter than in isobaric series; 3) the fractal dimension exists in the samples and there is good correlation between the fractal dimension and temperature/pressure. This study is a first trial of the characterization of individual cracks in 3D network. It lays a foundation for future research on the prediction of large-scale fractures in tight reservoirs.

Development and Verification of Sputtered Thin-Film Nickel-Titanium (NiTi) Shape Memory Alloy (SMA)

DTIC Science & Technology

2015-08-01

Shape Memory Alloy (SMA) by Cory R Knick and Christopher J Morris Approved for public release; distribution unlimited...Laboratory Development and Verification of Sputtered Thin-Film Nickel-Titanium (NiTi) Shape Memory Alloy (SMA) by Cory R Knick and Christopher

Retrospective Methods Analysis of Semiautomated Intracerebral Hemorrhage Volume Quantification From a Selection of the STICH II Cohort (Early Surgery Versus Initial Conservative Treatment in Patients With Spontaneous Supratentorial Lobar Intracerebral Haematomas).

PubMed

Haley, Mark D; Gregson, Barbara A; Mould, W Andrew; Hanley, Daniel F; Mendelow, Alexander David

2018-02-01

The ABC/2 method for calculating intracerebral hemorrhage (ICH) volume has been well validated. However, the formula, derived from the volume of an ellipse, assumes the shape of ICH is elliptical. We sought to compare the agreement of the ABC/2 formula with other methods through retrospective analysis of a selection of the STICH II cohort (Early Surgery Versus Initial Conservative Treatment in Patients With Spontaneous Supratentorial Lobar Intracerebral Haematomas). From 390 patients, 739 scans were selected from the STICH II image archive based on the availability of a CT scan compatible with OsiriX DICOM viewer. ICH volumes were calculated by the reference standard semiautomatic segmentation in OsiriX software and compared with calculated arithmetic methods (ABC/2, ABC/2.4, ABC/3, and 2/3SC) volumes. Volumes were compared by difference plots for specific groups: randomization ICH (n=374), 3- to 7-day postsurgical ICH (n=206), antithrombotic-associated ICH (n=79), irregular-shape ICH (n=703) and irregular-density ICH (n=650). Density and shape were measured by the Barras ordinal shape and density groups (1-5). The ABC/2.4 method had the closest agreement to the semiautomatic segmentation volume in all groups, except for the 3- to 7-day postsurgical ICH group where the ABC/3 method was superior. Although the ABC/2 formula for calculating elliptical ICH is well validated, it must be used with caution in ICH scans where the elliptical shape of ICH is a false assumption. We validated the adjustment of the ABC/2.4 method in randomization, antithrombotic-associated, heterogeneous-density, and irregular-shape ICH. URL: http://www.isrctn.com/ISRCTN22153967. Unique identifier: ISRCTN22153967. © 2018 American Heart Association, Inc.

DC heating induced shape transformation of Ge structures on ultraclean Si(5 5 12) surfaces.

PubMed

Dash, J K; Rath, A; Juluri, R R; Raman, P Santhana; Müller, K; Rosenauer, A; Satyam, P V

2011-04-06

We report the growth of Ge nanostructures and microstructures on ultraclean, high vicinal angle silicon surfaces and show that self-assembled growth at optimum thickness of the overlayer leads to interesting shape transformations, namely from nanoparticle to trapezoidal structures, at higher thickness values. Thin films of Ge of varying thickness from 3 to 12 ML were grown under ultrahigh vacuum conditions on a Si(5 5 12) substrate while keeping the substrate at a temperature of 600 °C. The substrate heating was achieved by two methods: (i) by heating a filament under the substrate (radiative heating, RH) and (ii) by passing direct current through the samples in three directions (perpendicular, parallel and at 45° to the (110) direction of the substrate). We find irregular, more spherical-like island structures under RH conditions. The shape transformations have been found under DC heating conditions and for Ge deposition more than 8 ML thick. The longer sides of the trapezoid structures are found to be along (110) irrespective of the DC current direction. We also show the absence of such a shape transformation in the case of Ge deposition on Si(111) substrates. Scanning transmission electron microscopy measurements suggested the mixing of Ge and Si. This has been confirmed with a quantitative estimation of the intermixing using Rutherford backscattering spectrometry (RBS) measurements. The role of DC heating in the formation of aligned structures is discussed. Although the RBS simulations show the presence of a possible SiO(x) layer, under the experimental conditions of the present study, the oxide layer would not play a role in determining the formation of the various structures that were reported here.

Universal router concept

NASA Technical Reports Server (NTRS)

Pesch, W. A.

1970-01-01

Portable universal router can cut holes of large diameter and irregular shapes, machine recesses, and drill holes with certain edge-distance limitations. Rectangular and round holes may be cut without a template.

An Impact Ejecta Behavior Model for Small, Irregular Bodies

NASA Technical Reports Server (NTRS)

Richardson, J. E.; Melosh, H. J.; Greenberg, R.

2003-01-01

In recent years, spacecraft observations of asteroids 951 Gaspra, 243 Ida, 253 Mathilde, and 433 Eros have shown the overriding dominance of impact processes with regard to the structure and surface morphology of these small, irregular bodies. In particular, impact ejecta play an important role in regolith formation, ranging from small particles to large blocks, as well as surface feature modification and obscuration. To investigate these processes, a numerical model has been developed based upon the impact ejecta scaling laws provided by Housen, Schmidt, and Holsapple, and modified to more properly simulate the late-stage ejection velocities and ejecta plume shape changes (ejection angle variations) shown in impact cratering experiments. A target strength parameter has also been added to allow the simulation of strength-dominated cratering events in addition to the more familiar gravity-dominated cratering events. The result is a dynamical simulation which models -- via tracer particles -- the ejecta plume behavior, ejecta blanket placement, and impact crater area resulting from a specified impact on an irregularly shaped target body, which is modeled in 3-dimensional polygon fashion. This target body can be placed in a simple rotation state about one of its principal axes, with the impact site and projectile/target parameters selected by the user. The gravitational force from the irregular target body (on each tracer particle) is determined using the polygonized surface (polyhedron) gravity technique developed by Werner.

Impaired capacity of cerebellar patients to perceive and learn two-dimensional shapes based on kinesthetic cues.

PubMed

Shimansky, Y; Saling, M; Wunderlich, D A; Bracha, V; Stelmach, G E; Bloedel, J R

1997-01-01

This study addresses the issue of the role of the cerebellum in the processing of sensory information by determining the capability of cerebellar patients to acquire and use kinesthetic cues received via the active or passive tracing of an irregular shape while blindfolded. Patients with cerebellar lesions and age-matched healthy controls were tested on four tasks: (1) learning to discriminate a reference shape from three others through the repeated tracing of the reference template; (2) reproducing the reference shape from memory by drawing blindfolded; (3) performing the same task with vision; and (4) visually recognizing the reference shape. The cues used to acquire and then to recognize the reference shape were generated under four conditions: (1) "active kinesthesia," in which cues were acquired by the blindfolded subject while actively tracing a reference template; (2) "passive kinesthesia," in which the tracing was performed while the hand was guided passively through the template; (3) "sequential vision," in which the shape was visualized by the serial exposure of small segments of its outline; and (4) "full vision," in which the entire shape was visualized. The sequential vision condition was employed to emulate the sequential way in which kinesthetic information is acquired while tracing the reference shape. The results demonstrate a substantial impairment of cerebellar patients in their capability to perceive two-dimensional irregular shapes based only on kinesthetic cues. There also is evidence that this deficit in part relates to a reduced capacity to integrate temporal sequences of sensory cues into a complete image useful for shape discrimination tasks or for reproducing the shape through drawing. Consequently, the cerebellum has an important role in this type of sensory information processing even when it is not directly associated with the execution of movements.

2009 Insensitive Munitions and Energetic Materials Technology Symposium

DTIC Science & Technology

2009-05-14

Multilayer Structure 1D STIMULI Flat end rod Round end rod Flat cookie -cutter Spherical fragment Simple shaped charge jet Real shaped charge jet Thin plate... cookie -cutter Spherical fragment Simple shaped charge jet Real shaped charge jet Thin plate Constant Temperature Rising Temperature Multilayer...Propellants  Plasticizer mixed into the Propellant - Dough NO SURFACE COATING Formulation Impetus (J/g) Flame Temp (K) Mw (g/mole) A

Low Vision Rehabilitation Intervention for People with Ring Scotomas

ERIC Educational Resources Information Center

Schoessow, Kimberly A.; Gilbert, Leah M.; Jackson, Mary Lou

2010-01-01

Central scotomas--areas of the nonseeing retina within the central 20 degrees of the visual field--are present in approximately 90% of vision rehabilitation patients. They vary in size and shape and can be small or large, symmetrical or asymmetrical, round or irregularly shaped. Most central scotomas border fixation on one side and can be overcome…

Shaping-lathe headrig now commercially available

Treesearch

P. Koch

1975-01-01

On September 12, 1975, twenty-five sawmillers from throughout North America watched as a new headrig produced cants of various shapes and a usable residue of flakes from logs of irregular contour. The demonstration at the Stetson-Ross plant in Seattle, Washington, was the unveiling of the commercial model of a design introduced by the Southern Forest Experiment Station...

Spongy Surface

NASA Image and Video Library

2015-06-02

NASA Cassini imaging scientists processed this view of Saturn moon Hyperion, taken during a close flyby on May 31, 2015. This flyby marks the mission final close approach to Saturn largest irregularly shaped moon.

Residual Cap

NASA Image and Video Library

2006-05-10

This MOC image shows a summertime view of the south polar residual cap of Mars. In this image, mesas composed largely of solid carbon dioxide are separated from one another by irregularly-shaped depressions

An investigation of water production rates by irregularly shaped cometary nuclei.

NASA Astrophysics Data System (ADS)

Gutierrez, P. J.; Ortiz, J. L.; Rodrigo, R.; Lopez-Moreno, J. J.

1999-09-01

A computer code has been developed to derive water production rates for rotating irregularly shaped nuclei with topography (both craters and mountains) as a function of heliocentric distance. The code solves the surface energy balance equation including heat diffusion in the normal direction and taking into account shadowing effects, for any combination of orbital parameters, spin axis orientation, rotation period, and physical properties of the nucleus (geometric albedo, emissivity, thermodynamical properties). Preliminary results are presented for several representative objects. The research described in this abstract is being carried out at the Instituto de Astrofísica de Andalucía and is supported by the Comision Interministerial de Ciencia y Tecnología under contracts ESP96-0623 and ESP97-1773-CO3-01.

Discrete dipole approximation models of chrystalline forsterite: Applications to cometary crystalline silicates

NASA Astrophysics Data System (ADS)

Lindsay, Sean Stephen

The shape, size, and composition of crystalline silicates observed in comet comae and external proto-planetary disks are indicative of the formation and evolution of the dust grains during the processes of planetary formation. In this dissertation, I present the 3 -- 40 mum absorption efficiencies( Qabs) of irregularly shaped forsterite crystals computed with the discrete dipole approximation (DDA) code DDSCAT developed by Draine and Flatau and run on the NASA Advanced Supercomputing facility Pleiades. An investigation of grain shapes ranging from spheroidal to irregular indicate that the strong spectral features from forsterite are sensitive to grain shape and are potentially degenerate with the effects of crystal solid state composition (Mg-content). The 10, 11, 18, 23, and 33.5 mum features are found to be the most crystal shape sensitive and should be avoided in determining Mg-content. The distinct spectral features for the three shape classes are connected with crystal formation environment using a condensation experiment by (Kobatake et al., 2008). The condensation experiment demonstrates that condensed forsterite crystal shapes are dependent on the condensation environmental temperature. I generate DDSCAT target analog shapes to the condensed crystal shapes. These analog shapes are represented by the three shape classes: 1) equant, 2) a, c-columns, and 3) b-shortened platelets. Each of these shape classes exhibit distinct spectral features that can be used to interpret grain shape characteristics from 8 --- 40 mum spectroscopy of astronomical objects containing crystalline silicates. Synthetic spectral energy distributions (SEDs) of the coma of Hale-Bopp at rh = 2.8 AU are generated by thermally modeling the flux contributions of 5 mineral species present in comets. The synthetic SEDs are constrained using a chi2- minimization technique. The mineral species are amorphous carbon, amorphous pyroxene, amorphous olivine, crystalline enstatite, and crystalline forsterite. Using the DDSCAT computed absorption efficiencies for a large variety of forsterite crystal shapes, which are computed for 66 grain sizes between 0.1 -- 5.0 mum, the flux contribution of irregularly shaped forsterite is computed. The forsterite flux contribution is then summed with the amorphous and crystalline enstatite contributions to generate the total synthetic SED. The DDSCAT forsterite grain shape synthetic SEDs reveal that the crystalline silicates in the coma of Hale-Bopp are irregular in shape with two distinct shape characteristics related to specific formation mechanisms: 1) equant grains with sharp ( ≲ 90°) angles between the faces, edges, and vertices that formed as high temperature condensates in the inner 1 -- 3 AU radial region of the Solar System's protoplanetary disk; and 2) c-shortened platelet shapes that likely formed from collisional processing of the crystals. The 8 -- 40 mum silicate spectral features of Hale-Bopp's coma are compared to the silicate spectral features of the comae of 17P/Holmes during 2007 outburst and 9P/Tempel 1 during the Deep Impact experiment to show that the silicate features with crystalline resonances are remarkably similar. The similarity in silicate spectral features suggests that the grain populations in the comae of these comets are similar in shape, size, and compositon. However, Hale-Bopp is a nearly isotropic comet (NIC) that dynamically came from the Oort cloud, and 17P and 9P are ecliptic comets (ECs) that dynamically came from the Scattered Disk. The different dynamical source regions yet similar silicate (amorphous and crystalline) grain populations suggest that ECs and NICs innately have similar grains and that the typically weaker silicate features of ECs are an effect of the surface grains becoming compacted with numerous perihelion passages. Hence, the differences in silicate between ECs and NICs are the result of grain structure and not grain composition. (Abstract shortened by UMI.)

Farewell to Hyperion

NASA Image and Video Library

2015-06-02

NASA Cassini imaging scientists processed this view of Saturn moon Hyperion, taken during a close flyby on May 31, 2015. This flyby marks the mission final close approach to Saturn largest irregularly shaped moon.

7 CFR 51.1317 - Well formed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States... characteristic of the variety. Slight irregularities of shape from type which do not appreciably detract from the...

Dynamics of deformation and pinch-off of a migrating compound droplet in a tube

NASA Astrophysics Data System (ADS)

Borthakur, Manash Pratim; Biswas, Gautam; Bandyopadhyay, Dipankar

2018-04-01

A computational fluid dynamic investigation has been carried out to study the dynamics of a moving compound droplet inside a tube. The motions associated with such a droplet is uncovered by solving the axisymmetric Navier-Stokes equations in which the spatiotemporal evolution of a pair of twin-deformable interfaces has been tracked employing the volume-of-fluid approach. The deformations at the interfaces and their subsequent dynamics are found to be stimulated by the subtle interplay between the capillary and viscous forces. The simulations uncover that when a compound drop composed of concentric inner and outer interfaces migrates inside a tube, initially in the unsteady domain of evolution, the inner drop shifts away from the concentric position to reach a morphology of constant eccentricity at the steady state. The coupled motions of the droplets in the unsteady regime causes a continuous deformation of the inner and outer interfaces to obtain a configuration with a (an) prolate (oblate) shaped outer (inner) interface. The magnitudes of capillary number and viscosity ratio are found to have significant influence on the temporal evolution of the interfacial deformations as well as the eccentricity of the droplets. Further, the simulations uncover that, following the asymmetric deformation of the interfaces, the migrating compound droplet can undergo an uncommon breakup stimulated by a rather irregular pinch-off of the outer shell. The breakup is found to initiate with the thinning of the outer shell followed by the pinch-off. Interestingly, the kinetics of the thinning of outer shell is found to follow two distinct power-law regimes—a swiftly thinning stage at the onset followed by a rate limiting stage before pinch-off, which eventually leads to the uncommon breakup of the migrating compound droplets.

Characterization of sputtering deposited NiTi shape memory thin films using a temperature controllable atomic force microscope

NASA Astrophysics Data System (ADS)

He, Q.; Huang, W. M.; Hong, M. H.; Wu, M. J.; Fu, Y. Q.; Chong, T. C.; Chellet, F.; Du, H. J.

2004-10-01

NiTi shape memory thin films are potentially desirable for micro-electro-mechanical system (MEMS) actuators, because they have a much higher work output per volume and also a significantly improved response speed due to a larger surface-to-volume ratio. A new technique using a temperature controllable atomic force microscope (AFM) is presented in order to find the transformation temperatures of NiTi shape memory thin films of micrometer size, since traditional techniques, such as differential scanning calorimetry (DSC) and the curvature method, have difficulty in dealing with samples of such a scale as this. This technique is based on the surface relief phenomenon in shape memory alloys upon thermal cycling. The reliability of this technique is investigated and compared with the DSC result in terms of the transformation fraction (xgr). It appears that the new technique is nondestructive, in situ and capable of characterizing sputtering deposited very small NiTi shape memory thin films.

Volcanic processes recorded by inclusions in sanidine megacrystals ejected from Quaternary Rockeskyll volcano, Eifel, Germany

NASA Astrophysics Data System (ADS)

Eilhard, Nicole; Schreuer, Jürgen; Stöckhert, Bernhard

2016-04-01

Sanidine megacrystals were ejected by a late stage explosive eruption at the Quaternary Rockeskyll volcanic complex, Eifel volcanic field, Germany. The homogeneous distribution of barium (about 1 % wt BaO equivalent to about 2 mole % celsian component) indicates that the nearly perfect single crystals must have crystallized in the Ostwald-Miers range from a huge reservoir, probably in the roof of a magma chamber. Irregularities during crystal growth caused trapping of hydrous melt inclusions, which are the objective of the present study. The inclusions show a characteristic concentric microstructure, in the following described from the sanidine host towards the inclusion center: (1) Ba is enriched by a factor of 2 to 3 in a ca. 0.01 mm wide rim, compared to the otherwise homogeneous sanidine host; (2) inwards, the continuous rim is overgrown by a thin crust of Ba enriched sanidine with irregular surface; (3) a layer of glass with a composition similar to sanidine; (4) a second, thinner layer of glass slightly reduced in Na2O and K2O, separated from the first glass layer by a sharp interface with approximately spherical shape; (5) a bubble containing a fluid phase, composed of H2O and minor CO2. This record is interpreted as follows: After crystallization of the sanidine megacrystals, a rise in temperature within the magmatic system caused some re-melting of the Ba-rich sanidine around the inclusions. Partitioning of Ba between the small included melt reservoir and the host caused formation of the Ba-rich rim (layer 1) by diffusive exchange. The onset of cooling lead to crystallization of the thin sanidine crust (layer 2). Finally, very rapid decompression and cooling during the subsequent explosive eruption caused sequential phase separation (two stages) in the remaining melt, the denser melt phase (layers 3 and 4) quenched to glass, the complementary low-density volatile-rich phase forming the central bubble. In summary, the microstructure and phase composition of the inclusions in the sanidine megacrystals recorded information on the history of the volcanic system prior to and during explosive eruption.

Sporadic-E Studies by Ionospheric Scintillation Using Ground-Based GPS and Radio Occultation Measurements

NASA Astrophysics Data System (ADS)

Seif, A.; Liu, T. J. Y.; Mannucci, A. J.; Carter, B. A.; Norman, R.

2016-12-01

The Global Navigation Satellite System (GNSS) based radio occultation (RO) technique provides an ideal limb-viewing geometry from space for studying the occurrence of sporadic E (Es). This study focuses on the detection and analysis of Es from RO measurements, to conclusively show the presence of Es's relationship with daytime scintillation. We bring two data sets to bear, using GNSS signal transmissions received on the ground and from space, which provide a unique opportunity to retrieve information about Es. RO signatures of Es and in GHz scintillation are not the same as ground-based signatures of Es. The viewing geometries are approximately orthogonal, which means the irregularity sources are not the same. That is, irregularities responsible for RO scintillations are essentially in a vertical plane, whereas those responsible for ground-based scintillations are essentially in a horizontal plane. Hence, complementary information is available regarding plasma structure in an Es patch. An analysis of combined data sets should prove to be a profitable avenue for research. In this study, we present the occurrence of scintillation using GPS Ionospheric Scintillation and Total Electron Content Monitor (GISTM) systems from two equatorial stations UKM (2.55°N, 101.46°E), and Langkawi (6.19°N, 99.51°E) in Malaysia. To better understand scale size irregularities as well as identify the occurrence of Es, we use COSMIC RO data. Two key findings coming out from our study are 1) According to the characteristics of daytime scintillation analyzed at, UKM and Langkawi stations, scintillation shows no significant TEC depletions and ROTI enhancements. The finding that ROTI does not exceed 0.5 TECU/min during daytime implies that large scale ionospheric irregularities with a scale length of a few kilometers do not exist at these stations. This is a piece of evidence which positively supports that daytime scintillation shows irregularities consistent with thin layer Es and supports the interpretation that a thin layer Es is responsible for producing daytime scintillation 2) The results obtained from GNSS RO measurements provide information on the existence of altitude and intensity of electron density irregularities at ionospheric E region height. This indicates that Es is associated with daytime GHz scintillation.

Organizational Learning and the Marine Corps: The Counterinsurgency Campaign in Iraq (CIWAG Case Study on Irregular Warfare and Armed Groups)

DTIC Science & Technology

2012-01-01

and institutional memory are seen as keys to their success in Anbar. Ten lessons are drawn from this case that relate to the future irregular conflict...organizational culture. Specialists on the topic like Richard Downie find that institutional memory and history, key factors that shape organizational culture...and practiced” they will “form … the organization’s institutional memory .” That memory is then socialized into its members, making the organization

The Haw River Sites: Archaeological Investigations at Two Stratified Sites in the North Carolina Piedmont. Volume II.

DTIC Science & Technology

1982-04-01

area of irregular shape. The area was filled with a mixture of tan alluvial sand and red clay. The irregular outline of the depression would suggest...suggests possible association of skinning racks. In the Navajo case (Binford and Bertram 1977) the use of the ax was greatly facilited by the suspension...llIlllllllllhll IIIIIIIIIIIIIIfllfllf mh•hE h E 1.5 MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDA r I9. A IU ... . ... ... *II l .. .. .... . . I

Evolutionary patterns of bone histology and bone compactness in xenarthran mammal long bones.

PubMed

Straehl, Fiona R; Scheyer, Torsten M; Forasiepi, Analía M; MacPhee, Ross D; Sánchez-Villagra, Marcelo R

2013-01-01

Bone microstructure reflects physiological characteristics and has been shown to contain phylogenetic and ecological signals. Although mammalian long bone histology is receiving increasing attention, systematic examination of the main clades has not yet been performed. Here we describe the long bone microstructure of Xenarthra based on thin sections representing twenty-two species. Additionally, patterns in bone compactness of humeri and femora are investigated. The primary bone tissue of xenarthran long bones is composed of a mixture of woven, parallel-fibered and lamellar bone. The vascular canals have a longitudinal, reticular or radial orientation and are mostly arranged in an irregular manner. Concentric rows of vascular canals and laminar organization of the tissue are only found in anteater bones. The long bones of adult specimens are marked by dense Haversian bone, a feature that has been noted for most groups of mammals. In the long bones of armadillos, secondary osteons have an oblique orientation within the three-dimensional bone tissue, thus resulting in their irregular shape when the bones are sectioned transversely. Secondary remodeling is generally more extensive in large taxa than in small taxa, and this could be caused by increased loading. Lines of arrested growth are assumed to be present in all specimens, but they are restricted to the outermost layer in bones of armadillos and are often masked by secondary remodeling in large taxa. Parameters of bone compactness show a pattern in the femur that separates Cingulata and Pilosa (Folivora and Vermilingua), with cingulates having a lower compactness than pilosans. In addition, cingulates show an allometric relationship between humeral and femoral bone compactness.

Effect of filler properties in composite resins on light transmittance characteristics and color.

PubMed

Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Takahashi, Hideo; Ban, Seiji

2007-01-01

The purpose of this investigation was to examine the effect of filler particle size and shape as well as filler content on light transmittance characteristics and color of experimental composite resins. A mixture of 30 mol% Bis-GMA and 70 mol% TEGDMA was prepared as a base monomer and to which a photoinitiator (camphorquinone) and a co-initiator (N,N-dimethylaminoethyl methacrylate) were added. Four different irregular- and spherical-shaped filler types with an average particle size of 1.9-11.1 microm were added to the mixture in three different filler contents of 20, 30, and 40 vol%. Light transmittance characteristics including light diffusion characteristics of the materials were evaluated. Color values and color differences among filler contents of the materials were also determined. Materials containing smaller and irregular-shaped fillers showed higher light transmittance and diffusion angle distribution with a sharper peak, as compared with those containing larger and spherical-shape fillers. It was also found that there was a significant correlation between the specific surface area of fillers and the color difference of the materials containing the fillers. Our results indicated that the shape of filler particles, as well as particle size and filler content, significantly affected the light transmittance characteristics--including light diffusion characteristics--and color of composite resins.

Estimating pore and cement volumes in thin section

USGS Publications Warehouse

Halley, R.B.

1978-01-01

Point count estimates of pore, grain and cement volumes from thin sections are inaccurate, often by more than 100 percent, even though they may be surprisingly precise (reproducibility + or - 3 percent). Errors are produced by: 1) inclusion of submicroscopic pore space within solid volume and 2) edge effects caused by grain curvature within a 30-micron thick thin section. Submicroscopic porosity may be measured by various physical tests or may be visually estimated from scanning electron micrographs. Edge error takes the form of an envelope around grains and increases with decreasing grain size and sorting, increasing grain irregularity and tighter grain packing. Cements are greatly involved in edge error because of their position at grain peripheries and their generally small grain size. Edge error is minimized by methods which reduce the thickness of the sample viewed during point counting. Methods which effectively reduce thickness include use of ultra-thin thin sections or acetate peels, point counting in reflected light, or carefully focusing and counting on the upper surface of the thin section.

Extended Multiscale Image Segmentation for Castellated Wall Management

NASA Astrophysics Data System (ADS)

Sakamoto, M.; Tsuguchi, M.; Chhatkuli, S.; Satoh, T.

2018-05-01

Castellated walls are positioned as tangible cultural heritage, which require regular maintenance to preserve their original state. For the demolition and repair work of the castellated wall, it is necessary to identify the individual stones constituting the wall. However, conventional approaches using laser scanning or integrated circuits (IC) tags were very time-consuming and cumbersome. Therefore, we herein propose an efficient approach for castellated wall management based on an extended multiscale image segmentation technique. In this approach, individual stone polygons are extracted from the castellated wall image and are associated with a stone management database. First, to improve the performance of the extraction of individual stone polygons having a convex shape, we developed a new shape criterion named convex hull fitness in the image segmentation process and confirmed its effectiveness. Next, we discussed the stone management database and its beneficial utilization in the repair work of castellated walls. Subsequently, we proposed irregular-shape indexes that are helpful for evaluating the stone shape and the stability of the stone arrangement state in castellated walls. Finally, we demonstrated an application of the proposed method for a typical castellated wall in Japan. Consequently, we confirmed that the stone polygons can be extracted with an acceptable level. Further, the condition of the shapes and the layout of the stones could be visually judged with the proposed irregular-shape indexes.

Canuleia Crater

NASA Image and Video Library

2012-04-24

This image from NASA Dawn spacecraft of asteroid Vesta shows Canuleia crater, a large, irregularly shaped crater. Other interesting features of Canuleia include the diffuse bright material that is both inside and outside of its rim.

Capturing Nix and Hydra

NASA Image and Video Library

2015-07-21

NASA New Horizons spacecraft captured these images of Pluto moon Nix which shows a reddish spot that has attracted the interest of the mission scientists left, and the small, irregularly shaped moon Hydra right.

Developing Mathematical Knowledge and Skills through the Awareness Approach of Teaching and Learning

ERIC Educational Resources Information Center

Cherif, Abour H.; Gialamas, Stefanos; Stamati, Angeliki

2017-01-01

Every object we think of or encounter, whether a natural or human-made, has a regular or irregular shape. In its own intrinsic conceptual design, it has elements of mathematics, science, engineering, and arts, etc., which are part of the object's geometric shape, form and structure. Geometry is not only an important part of mathematics, but it is…

A flexibly shaped space-time scan statistic for disease outbreak detection and monitoring.

PubMed

Takahashi, Kunihiko; Kulldorff, Martin; Tango, Toshiro; Yih, Katherine

2008-04-11

Early detection of disease outbreaks enables public health officials to implement disease control and prevention measures at the earliest possible time. A time periodic geographical disease surveillance system based on a cylindrical space-time scan statistic has been used extensively for disease surveillance along with the SaTScan software. In the purely spatial setting, many different methods have been proposed to detect spatial disease clusters. In particular, some spatial scan statistics are aimed at detecting irregularly shaped clusters which may not be detected by the circular spatial scan statistic. Based on the flexible purely spatial scan statistic, we propose a flexibly shaped space-time scan statistic for early detection of disease outbreaks. The performance of the proposed space-time scan statistic is compared with that of the cylindrical scan statistic using benchmark data. In order to compare their performances, we have developed a space-time power distribution by extending the purely spatial bivariate power distribution. Daily syndromic surveillance data in Massachusetts, USA, are used to illustrate the proposed test statistic. The flexible space-time scan statistic is well suited for detecting and monitoring disease outbreaks in irregularly shaped areas.

Analysis and characterization of high-resolution and high-aspect-ratio imaging fiber bundles.

PubMed

Motamedi, Nojan; Karbasi, Salman; Ford, Joseph E; Lomakin, Vitaliy

2015-11-10

High-contrast imaging fiber bundles (FBs) are characterized and modeled for wide-angle and high-resolution imaging applications. Scanning electron microscope images of FB cross sections are taken to measure physical parameters and verify the variations of irregular fibers due to the fabrication process. Modal analysis tools are developed that include irregularities in the fiber core shapes and provide results in agreement with experimental measurements. The modeling demonstrates that the irregular fibers significantly outperform a perfectly regular "ideal" array. Using this method, FBs are designed that can provide high contrast with core pitches of only a few wavelengths of the guided light. Structural modifications of the commercially available FB can reduce the core pitch by 60% for higher resolution image relay.

Shape dependent phoretic propulsion of slender active particles

NASA Astrophysics Data System (ADS)

Ibrahim, Y.; Golestanian, R.; Liverpool, T. B.

2018-03-01

We theoretically study the self-propulsion of a thin (slender) colloid driven by asymmetric chemical reactions on its surface at vanishing Reynolds number. Using the method of matched asymptotic expansions, we obtain the colloid self-propulsion velocity as a function of its shape and surface physicochemical properties. The mechanics of self-phoresis for rod-like swimmers has a richer spectrum of behaviors than spherical swimmers due to the presence of two small length scales, the slenderness of the rod and the width of the slip layer. This leads to subtleties in taking the limit of vanishing slenderness. As a result, even for very thin rods, the distribution of curvature along the surface of the swimmer, namely, its shape, plays a surprising role in determining the efficiency of propulsion. We find that thin cylindrical self-phoretic swimmers with blunt ends move faster than thin prolate spheroid shaped swimmers with the same aspect ratio.

Multilayer composites and manufacture of same

DOEpatents

Holesinger, Terry G.; Jia, Quanxi

2006-02-07

The present invention is directed towards a process of depositing multilayer thin films, disk-shaped targets for deposition of multilayer thin films by a pulsed laser or pulsed electron beam deposition process, where the disk-shaped targets include at least two segments with differing compositions, and a multilayer thin film structure having alternating layers of a first composition and a second composition, a pair of the alternating layers defining a bi-layer wherein the thin film structure includes at least 20 bi-layers per micron of thin film such that an individual bi-layer has a thickness of less than about 100 nanometers.

Age-dependent change in the morphology of nucleoli and methylation of genes of the Nucleolar Organizer Region in Japanese quail Coturnix japonica) model (Temminck and Schlegel, 1849) (Galliformes: Aves).

PubMed

Andraszek, Katarzyna; Gryzińska, Magdalena; Wójcik, Ewa; Knaga, Sebastian; Smalec, Elżbieta

2014-01-01

Nucleoli are the product of the activity of nucleolar organizer regions (NOR) in certain chromosomes. Their main functions are the formation of ribosomal subunits from ribosomal protein molecules and the transcription of genes encoding rRNA. The aim of the study was to determine the shape of nucleoli and analyse methylation in the gene RN28S in the spermatocytes of male Japanese quail (Coturnixjaponica) in two age groups. Nucleoli were analysed in cells of the first meiotic prophase. Their number and shape were determined and they were classified as regular, irregular or defragmented. In the cells of the young birds no defragmented nucleoli were observed, with regular and irregular nucleoli accounting for 97% and 3%, respectively. In the cells of older birds no regular nucleoli were observed, while irregular and defragmented nucleoli accounted for 37% and 67%, respectively. MSP (methylation-specific PCR) showed that the gene RN28S is methylated in both 15-week-old and 52-week-old quails. In recent years an association has been established between nucleolus morphology and cellular ageing processes.

Chemical vapor deposited silica coatings for solar mirror protection

NASA Technical Reports Server (NTRS)

Gulino, Daniel A.; Dever, Therese M.; Banholzer, William F.

1988-01-01

A variety of techniques is available to apply protective coatings to oxidation susceptible spacecraft components, and each has associated advantages and disadvantages. Film applications by means of chemical vapor deposition (CVD) has the advantage of being able to be applied conformally to objects of irregular shape. For this reason, a study was made of the oxygen plasma durability of thin film (less than 5000 A) silicon dioxide coatings applied by CVD. In these experiments, such coatings were applied to silver mirrors, which are strongly subject to oxidation, and which are proposed for use on the space station solar dynamic power system. Results indicate that such coatings can provide adequate protection without affecting the reflectance of the mirror. Scanning electron micrographs indicated that oxidation of the silver layer did occur at stress crack locations, but this did not affect the measured solar reflectances. Oxidation of the silver did not proceed beyond the immediate location of the crack. Such stress cracks did not occur in thinner silica flims, and hence such films would be desirable for this application.

Chemical vapor deposited silica coatings for solar mirror protection

NASA Technical Reports Server (NTRS)

Gulino, Daniel A.; Dever, Therese M.; Banholzer, William F.

1988-01-01

A variety of techniques is available to apply protective coatings to oxidation susceptible spacecraft components, and each has associated advantages and disadvantages. Film applications by means of chemical vapor deposition (CVD) has the advantage of being able to be applied conformally to objects of irregular shape. For this reason, a study was made of the oxygen plasma durability of thin film (less than 5000 A) silicon dioxide coatings applied by CVD. In these experiments, such coatings were applied to silver mirrors, which are strongly subject to oxidation, and which are proposed for use on the space station solar dynamic power system. Results indicate that such coatings can provide adequate protection without affecting the reflectance of the mirror. Scanning electron micrographs indicated that oxidation of the silver layer did occur at stress crack locations, but this did not affect the measured solar reflectances. Oxidation of the silver did not proceed beyond the immediate location of the crack. Such stress cracks did not occur in thinner silica films, and hence such films would be desirable for this application.

Thruster residues on returned Mir solar panel

NASA Astrophysics Data System (ADS)

Harvey, Gale A.

2000-09-01

A solar panel with more than ten years space exposure was returned to Earth in January 1998. Several types of residues were deposited or transported onto the solar cell coverglasses during the space exposure. Self-contamination of SiOx films from the silicone potting compound was a major contamination of the coverglasses. A second type of contamination was thick, detergent-like residues of the order of a millimeter diameter on many, but not most of the coverglasses. A third, prevalent type of contamination was very thin irregular shaped films or patterns of a millimeter size which are readily visible in brilliant colors when the coverglasses are viewed with a 50x brightfield microscope. These prolific, overlapping, and almost ubiquitous patterns strongly suggest wetting on the surface. The probably cause of most of the wetted patterns on the returned Mir solar cell coverglasses is trace hydrazine nitrate in condensed water droplets produced as reaction products from Mir's and the Orbiters' hypergolic thrusters. This paper presents some of the wetted patterns, information regarding hypergolic reaction products, and type of thrusters associated with Mir operations.

Cemento-ossifying fibroma in a patient with end-stage renal disease.

PubMed

Gopinath, Divya; Beena, V T; Sugirtharaj, G; Vidhyadharan, K; Salmanul Faris, K; Kumar, Sajai J

2013-01-01

The presence of chronic renal disease (CRD) is a predisposing factor for the occurrence of soft and hard tissue lesions in the oral cavity. The cemento-ossifying fibroma (COF) is an uncommon benign fibroosseous lesion composed of fibrocellular component and calcified materials like cementum and woven bone. A 37-year-old female patient undergoing chronic haemodialysis reported to our institution with a complaint of slow growing, nontender swelling of mandible of 6-month duration. Computed tomography disclosed an ill-defined lesion showing thinning and expansion of buccal as well as lingual cortical plate with flecks of radiopacity in centre. Incision biopsy revealed histological characteristics consistent with cemento-ossifying fibroma. The lesion was excised under local anesthesia. The histopathological examination revealed irregularly shaped bone and cementum-like hard tissue calcifications contained within hypercellular fibrous tissue stroma, leading to a confirmation of the diagnosis of cemento-ossifying fibroma. This paper aims to provide light to the fact that the soft and hard tissues of the oral region may become susceptible to the development of pathological growths in case of some particular systemic conditions.

Cemento-Ossifying Fibroma in a Patient with End-Stage Renal Disease

PubMed Central

Gopinath, Divya; Beena, V. T.; Sugirtharaj, G.; Vidhyadharan, K.; Salmanul Faris, K.; Kumar, Sajai J.

2013-01-01

The presence of chronic renal disease (CRD) is a predisposing factor for the occurrence of soft and hard tissue lesions in the oral cavity. The cemento-ossifying fibroma (COF) is an uncommon benign fibroosseous lesion composed of fibrocellular component and calcified materials like cementum and woven bone. A 37-year-old female patient undergoing chronic haemodialysis reported to our institution with a complaint of slow growing, nontender swelling of mandible of 6-month duration. Computed tomography disclosed an ill-defined lesion showing thinning and expansion of buccal as well as lingual cortical plate with flecks of radiopacity in centre. Incision biopsy revealed histological characteristics consistent with cemento-ossifying fibroma. The lesion was excised under local anesthesia. The histopathological examination revealed irregularly shaped bone and cementum-like hard tissue calcifications contained within hypercellular fibrous tissue stroma, leading to a confirmation of the diagnosis of cemento-ossifying fibroma. This paper aims to provide light to the fact that the soft and hard tissues of the oral region may become susceptible to the development of pathological growths in case of some particular systemic conditions. PMID:23819070

Microstructure evolution of Al-doped zinc oxide films prepared by in-line reactive mid-frequency magnetron sputtering

NASA Astrophysics Data System (ADS)

Hong, R. J.; Jiang, X.

2006-07-01

Aluminium-doped zinc oxide (ZnO:Al or AZO) thin films were deposited on glass substrates by reactive mid-frequency (MF) magnetron sputtering from Zn/Al metallic targets. Strong (002) preferred orientation was detected by X-ray diffraction (XRD). It was observed by plan-view transmission electron microscopy (TEM) that an AZO film deposited at low substrate temperature was composed of irregular large grains; but the film prepared at high temperature was composed of moderate sized grains with a regular shape. A secondary phase of ZnO2 was also observed for the film deposited at low substrate temperature. The cross-sectional TEM study of the AZO film showed that prior to the well-aligned columnar growth an initial interfacial zone with nano crystallites were formed. The nano crystallites formed initially with a large tilt angle normal to the substrate surface and during the growth of the transition zone, the tilt angle decreased until it vanished. The evolution of the film structure is discussed in terms of evolutionary selection model and the dynamic deposition process.

Reynolds number effects on the aerodynamic characteristics of irregular planform wings at Mach number 0.3. [in the Ames 12 ft pressure wind tunnel

NASA Technical Reports Server (NTRS)

Kruse, R. L.; Lovette, G. H.; Spencer, B., Jr.

1977-01-01

The subsonic aerodynamic characteristics of a series of irregular planform wings were studied in wind tunnel tests conducted at M = 0.3 over a range of Reynolds numbers from 1.6 million to 26 million/m. The five basic wing planforms varied from a trapezoidal to a delta shape. Leading edge extensions, added to the basic shape, varied in approximately 5 deg increments from the wing leading edge sweep-back angle to a maximum 80 deg. Most of the tests were conducted using an NACA 0008 airfoil section with grit boundary layer trips. Tests were also conducted using an NACA 0012 airfoil section and an 8% thick wedge. In addition, the effect of free transition (no grit) was investigated. A body was used on all models.

Adaptive striping watershed segmentation method for processing microscopic images of overlapping irregular-shaped and multicentre particles.

PubMed

Xiao, X; Bai, B; Xu, N; Wu, K

2015-04-01

Oversegmentation is a major drawback of the morphological watershed algorithm. Here, we study and reveal that the oversegmentation is not only because of the irregular shapes of the particle images, which people are familiar with, but also because of some particles, such as ellipses, with more than one centre. A new parameter, the striping level, is introduced and the criterion for striping parameter is built to help find the right markers prior to segmentation. An adaptive striping watershed algorithm is established by applying a procedure, called the marker searching algorithm, to find the markers, which can effectively suppress the oversegmentation. The effectiveness of the proposed method is validated by analysing some typical particle images including the images of gold nanorod ensembles. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

A new approach of sensorial evaluation of cooked cereal foods: fractal analysis of rheological data

NASA Astrophysics Data System (ADS)

Scher, J.; Hardy, J.

2002-11-01

An analytical method based on a fractal geometry concept was developed through the relationship between structure-texture of solid-like crackers, flat bread and Bretzels. An universal testing machine was used to determine indentation tests. The graphs were irregularly shaped so that usual interpretation was made not possible. Nevertheless, the irregular shape, or “roughness" displays auto-similarity properties which can be interpreted in terms of apparent fractal dimension texture (D_T). A trained panel able to quantify the “hardness", “porous structure" and “crispness" descriptors carried out sensorial characterisation of products. High correlation between sensorial hardness and resistance to indentation, on one hand, and between crispness and D_T on the other hand was found. Modelling mathematics methods for complex systems allow useful contribution to Food Science.

High-resolution investigation of longitudinal modes of a GaN-based blue laser diode

NASA Astrophysics Data System (ADS)

Al-Basheer, Watheq; Aljalal, Abdulaziz; Gasmi, Khaled; Adigun, Taofeek O.

2017-05-01

Typical emission spectra of GaN-based blue laser diodes are known to have irregular shapes. Hence, well-resolved study of their spectra may help in understanding the origin of their spectral shapes irregularity. In this paper, the spectra of a commercial GaN-based blue laser diode are studied as a function of injection current and temperature using a spectrometer with highresolution of 0.003-nm over the spectral region 440 - 450 nm. The obtained laser spectra are used to track the longitudinal modes evolution as a function of operating currents and temperatures as well as to precisely map single mode operation. In addition, yielded laser spectra will be utilized to evaluate few parameters related to the laser diode, such as mode spacing, optical gain, slope efficiency and threshold current at certain temperature.

Clinical, morphological, and hemodynamic independent characteristic factors for rupture of posterior communicating artery aneurysms.

PubMed

Zhang, Ying; Jing, Linkai; Liu, Jian; Li, Chuanhui; Fan, Jixing; Wang, Shengzhang; Li, Haiyun; Yang, Xinjian

2016-08-01

To identify clinical, morphological, and hemodynamic independent characteristic factors that discriminate posterior communicating artery (PCoA) aneurysm rupture status. 173 patients with single PCoA aneurysms (108 ruptured, 65 unruptured) between January 2012 and June 2014 were retrospectively collected. Patient-specific models based on their three-dimensional digital subtraction angiography images were constructed and analyzed by a computational fluid dynamic method. All variables were analyzed by univariate analysis and multivariate logistic regression analysis. Two clinical factors (younger age and atherosclerosis), three morphological factors (higher aspect ratio, bifurcation type, and irregular shape), and six hemodynamic factors (lower mean and minimum wall shear stress, higher oscillatory shear index, a greater portion of area under low wall shear stress, unstable and complex flow pattern) were significantly associated with PCoA aneurysm rupture. Independent factors characterizing the rupture status were identified as age (OR 0.956, p=0.015), irregular shape (OR 6.709, p<0.001), and minimum wall shear stress (OR 0.001, p=0.038). We combined clinical, morphological, and hemodynamic characteristics analysis and found the three strongest independent factors for PCoA aneurysm rupture were younger age, irregular shape, and low minimum wall shear stress. This may be useful for guiding risk assessments and subsequent treatment decisions for PCoA aneurysms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Volume determination of irregularly-shaped quasi-spherical nanoparticles.

PubMed

Attota, Ravi Kiran; Liu, Eileen Cherry

2016-11-01

Nanoparticles (NPs) are widely used in diverse application areas, such as medicine, engineering, and cosmetics. The size (or volume) of NPs is one of the most important parameters for their successful application. It is relatively straightforward to determine the volume of regular NPs such as spheres and cubes from a one-dimensional or two-dimensional measurement. However, due to the three-dimensional nature of NPs, it is challenging to determine the proper physical size of many types of regularly and irregularly-shaped quasi-spherical NPs at high-throughput using a single tool. Here, we present a relatively simple method that determines a better volume estimate of NPs by combining measurements from their top-down projection areas and peak heights using two tools. The proposed method is significantly faster and more economical than the electron tomography method. We demonstrate the improved accuracy of the combined method over scanning electron microscopy (SEM) or atomic force microscopy (AFM) alone by using modeling, simulations, and measurements. This study also exposes the existence of inherent measurement biases for both SEM and AFM, which usually produce larger measured diameters with SEM than with AFM. However, in some cases SEM measured diameters appear to have less error compared to AFM measured diameters, especially for widely used IS-NPs such as of gold, and silver. The method provides a much needed, proper high-throughput volumetric measurement method useful for many applications. Graphical Abstract The combined method for volume determination of irregularly-shaped quasi-spherical nanoparticles.

SU-F-BRCD-03: Dose Calculation of Electron Therapy Using Improved Lateral Buildup Ratio Method.

PubMed

Gebreamlak, W; Tedeschi, D; Alkhatib, H

2012-06-01

To calculate the percentage depth dose of any irregular shape electron beam using modified lateral build-up-ratio method. Percentage depth dose (PDD) curves were measured using 6, 9, 12, and 15MeV electron beam energies for applicator cone sizes of 6×6, 10×10, 14×14, and 14×14cm 2 . Circular cutouts for each cone were prepared from 2.0cm diameter to the maximum possible size for each cone. In addition, three irregular cutouts were prepared. The scanning was done using a water tank and two diodes - one for the signal and the other a stationary reference outside the tank. The water surface was determined by scanning the signal diode slowly from water to air and by noting the sharp change of the percentage depth dose curve at the water/air interface. The lateral build-up-ratio (LBR) for each circular cutout was calculated from the measured PDD curve using the open field of the 14×14 cm 2 cone as the reference field. Using the LBR values and the radius of the circular cutouts, the corresponding lateral spread parameter (sigma) of the electron shower was calculated. Unlike the commonly accepted assumption that sigma is independent of cutout size, it is shown that the sigma value increases linearly with circular cutout size. Using this characteristic of sigma, the PDD curves of irregularly shaped cutouts were calculated. Finally, the calculated PDD curves were compared with measured PDD curves. In this research, it is shown that sigma increases with cutout size. For radius of circular cutout sizes up to the equilibrium range of the electron beam, the increase of sigma with the cutout size is linear. The percentage difference of the calculated PDD from the measured PDD for irregularly shaped cutouts was under 1.0%. Similar Result was obtained for four electron beam energies (6, 9, 12, and 15MeV). © 2012 American Association of Physicists in Medicine.

An ultrastructural analysis of the epithelial-fiber interface (EFI) in primate lenses.

PubMed

Kuszak, J R; Novak, L A; Brown, H G

1995-11-01

The purpose of this study was to conduct a comprehensive ultrastructural analysis of the epithelial-fiber interface (EFI) in normal adult primate (Macaque nemestrina and fascicularis; 6-9 years old, n = 10) lenses. Scanning electron microscopy (SEM) was used to initially characterize the gross size, shape and three-dimensional organization of central zone (cz) epithelial cells and the anterior ends of elongating fibers beneath these cells. This fiducial information was essential to properly orient lens pieces in freeze fracture specimen carriers for the production of replicas with unambiguously identifiable EFI. Transmission electron microscopy (TEM) of replicas and thin-sectioned material were used to ultrastructurally analyse the cz EFI. TEM thin-sectioned material was also used to ultrastructurally analyse the pregerminative (pgz), germinative (gz) and transitional zone (tz) EFI. Correlative SEM and TEM of cz EFI components revealed that the apical membrane of both epithelial and elongating fiber cells were irregularly polygonal in shape, and aligned in parallel as smooth, concave-convex surfaces. However, whereas epithelial cell apical surfaces had minimal size variation, elongating fibers were larger and considerably variable in size. Quantitative analysis of > 10000 micron2 cz elongating fiber apical surfaces failed to detect any gap junctions defined in freeze fracture replicas as complementary aggregates of transmembrane proteins (connexons) conjoined across a narrowed extracellular space. However, a comparable frequency of vesicular events was noted in this region as quantified previously in adult and embryonic chick lens. Correlative TEM analysis > 1500 linear micrometers of thin-sectioned EFI from this region confirmed the presence of epithelial-epithelial gap junctions, elongating fiber-elongating fiber gap junctions, and an extreme paucity of epithelial-elongating fiber gap junctions. In contrast, TEM analysis of > 1000 linear micrometers of thin-sectioned pgz, gz and tz EFI, confirmed the presence of epithelial-epithelial gap junctions, elongating fiber-elongating fiber gap junctions, numerous epithelial-elongating fiber adherens junctions and a few epithelial-elongating fiber gap junctions. Thus, the results of this and previous quantitative morphological and physiological studies (electronic and dye coupling) demonstrate that there is limited coupling between cz epithelial cells and underlying elongating fibers. Furthermore, the absence of gap junctional plaques in cz EFI freeze-fracture replicas and either pentalaminar or septalaminar profiles in correlative thin-sections, suggests that this limited coupling could be mediated via isolated gap junction channels. However, the results of this and previous quantitative studies further show that a greater degree of coupling exists across the pgz, gz and tz regions of the EFI and that this coupling is likely to be mediated by gap junction plaques. Finally, this and other studies continue to demonstrate that transcytotic processes play a role in lens physiology at the EFI.

Two-phase nc-TiN/a-(C,CN{sub x}) nanocomposite films: A HRTEM and MC simulation study

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

Guo, J.; Lu, Y. H.; Hu, X. J.

2013-06-18

The grain growth in two-phase nanocomposite Ti-C{sub x}-N{sub y} thin films grown by reactive close-field unbalanced magnetron sputtering in an Ar-N{sub 2} gas mixture with microstructures comprising of nanocrystalline (nc-) Ti(N,C) phase surrounded by amorphous (a-) (C,CN{sub x}) phase was investigated by a combination of high-resolution transmission electron microscopy (HRTEM) and Monte Carlo (MC) simulations. The HRTEM results revealed that amorphous-free solid solution Ti(C,N) thin films exhibited polycrystallites with different sizes, orientations and irregular shapes. The grain size varied in the range between several nanometers and several decade nanometers. Further increase of C content (up to {approx}19 at.% C) mademore » the amorphous phase wet nanocrystallites, which strongly hindered the growth of nanocrystallites. As a result, more regular Ti(C,N) nanocrystallites with an average size of {approx}5 nm were found to be separated by {approx}0.5-nm amorphous phases. When C content was further increased (up to {approx}48 at.% in this study), thicker amorphous matrices were produced and followed by the formation of smaller sized grains with lognormal distribution. Our MC analysis indicated that with increasing amorphous volume fraction (i.e. increasing C content), the transformation from nc/nc grain boundary (GB)-curvature-driven growth to a/nc GB-curvature-driven growth is directly responsible for the observed grain growth from great inhomogeneity to homogeneity process.« less

Refractive errors and corrections for OCT images in an inflated lung phantom

PubMed Central

Golabchi, Ali; Faust, J.; Golabchi, F. N.; Brooks, D. H.; Gouldstone, A.; DiMarzio, C. A.

2012-01-01

Visualization and correct assessment of alveolar volume via intact lung imaging is important to study and assess respiratory mechanics. Optical Coherence Tomography (OCT), a real-time imaging technique based on near-infrared interferometry, can image several layers of distal alveoli in intact, ex vivo lung tissue. However optical effects associated with heterogeneity of lung tissue, including the refraction caused by air-tissue interfaces along alveoli and duct walls, and changes in speed of light as it travels through the tissue, result in inaccurate measurement of alveolar volume. Experimentally such errors have been difficult to analyze because of lack of ’ground truth,’ as the lung has a unique microstructure of liquid-coated thin walls surrounding relatively large airspaces, which is difficult to model with cellular foams. In addition, both lung and foams contain airspaces of highly irregular shape, further complicating quantitative measurement of optical artifacts and correction. To address this we have adapted the Bragg-Nye bubble raft, a crystalline two-dimensional arrangement of elements similar in geometry to alveoli (up to several hundred μm in diameter with thin walls) as an inflated lung phantom in order to understand, analyze and correct these errors. By applying exact optical ray tracing on OCT images of the bubble raft, the errors are predicted and corrected. The results are validated by imaging the bubble raft with OCT from one edge and with a charged coupled device (CCD) camera in transillumination from top, providing ground truth for the OCT. PMID:22567599

Electroerosion micro- and nanopowders for the production of hard alloys

NASA Astrophysics Data System (ADS)

Latypov, R. A.; Ageeva, E. V.; Kruglyakov, O. V.; Latypova, G. R.

2016-06-01

The shape and the surface morphology of the powder particles fabricated by the electroerosion dispersion of tungsten-containing wastes in illuminating oil are studied. The hard alloy fabricated from these powder particles is analyzed by electron-probe microanalysis. The powder synthesized by the electroerosion dispersion of the wastes of sintered hard alloys is found to consist of particles of a spherical or elliptical shape, an irregular shape (conglomerates), and a fragment shape. It is shown that W, Ti, and Co are the main elements in the hard alloy fabricated from the powder synthesized by electroerosion dispersion in illuminating oil.

Method for producing ceramic particles and agglomerates

DOEpatents

Phillips, Jonathan; Gleiman, Seth S.; Chen, Chun-Ku

2001-01-01

A method for generating spherical and irregularly shaped dense particles of ceramic oxides having a controlled particle size and particle size distribution. An aerosol containing precursor particles of oxide ceramics is directed into a plasma. As the particles flow through the hot zone of the plasma, they melt, collide, and join to form larger particles. If these larger particles remain in the hot zone, they continue melting and acquire a spherical shape that is retained after they exit the hot zone, cool down, and solidify. If they exit the hot zone before melting completely, their irregular shape persists and agglomerates are produced. The size and size distribution of the dense product particles can be controlled by adjusting several parameters, the most important in the case of powder precursors appears to be the density of powder in the aerosol stream that enters the plasma hot zone. This suggests that particle collision rate is responsible for determining ultimate size of the resulting sphere or agglomerate. Other parameters, particularly the gas flow rates and the microwave power, are also adjusted to control the particle size distribution.

A scattering database of marine particles and its application in optical analysis

NASA Astrophysics Data System (ADS)

Xu, G.; Yang, P.; Kattawar, G.; Zhang, X.

2016-12-01

In modeling the scattering properties of marine particles (e.g. phytoplankton), the laboratory studies imply a need to properly account for the influence of particle morphology, in addition to size and composition. In this study, a marine particle scattering database is constructed using a collection of distorted hexahedral shapes. Specifically, the scattering properties of each size bin and refractive index are obtained by the ensemble average associated with distorted hexahedra with randomly tilted facets and selected aspect ratios (from elongated to flattened). The randomness degree in shape-generation process defines the geometric irregularity of the particles in the group. The geometric irregularity and particle aspect ratios constitute a set of "shape factors" to be accounted for (e.g. in best-fit analysis). To cover most of the marine particle size range, we combine the Invariant Imbedding T-matrix (II-TM) method and the Physical-Geometric Optics Hybrid (PGOH) method in the calculations. The simulated optical properties are shown and compared with those obtained from Lorenz-Mie Theory. Using the scattering database, we present a preliminary optical analysis of laboratory-measured optical properties of marine particles.

Morphology and phase identification of synthesized precipitated calcium carbonate from acetylene gas industry waste

NASA Astrophysics Data System (ADS)

Sabri, Siti Noorzidah Mohd; Othman, Rohaya; Othman, Anuar

2017-12-01

Precipitated calcium carbonate (PCC) is also known as synthetic calcium carbonate. In this paper, PCC was synthesized from carbide lime, which is the by-product from acetylene gas industry. The method used to produce PCC from carbide lime waste was ionic sucrose precipitation technique. The experiments were performed by varying the stirring rate. In this technique, carbide lime was first dissolved in ionic sucrose solution and then chilled at 10 °C for 24 hours before carbon dioxide gasses was introduced into the solution. The carbonation and precipitation process was took place and PCC was formed. The PCC was further filtered to obtain the solid PCC. The sample was then further characterised by using FESEM and XRD to determine the morphology and to identify the phase that exists in the synthesized compound respectively. The XRD and FESEM results clearly shown that the PCC obtained has mixed phases of calcite and vaterite, with mixtures of spherical and irregular shape morphologies formed. The irregular shapes corresponded to vaterite formation, meanwhile spherical shapes corresponded to calcite formation.

Particle shape accounts for instrumental discrepancy in ice core dust size distributions

NASA Astrophysics Data System (ADS)

Folden Simonsen, Marius; Cremonesi, Llorenç; Baccolo, Giovanni; Bosch, Samuel; Delmonte, Barbara; Erhardt, Tobias; Kjær, Helle Astrid; Potenza, Marco; Svensson, Anders; Vallelonga, Paul

2018-05-01

The Klotz Abakus laser sensor and the Coulter counter are both used for measuring the size distribution of insoluble mineral dust particles in ice cores. While the Coulter counter measures particle volume accurately, the equivalent Abakus instrument measurement deviates substantially from the Coulter counter. We show that the difference between the Abakus and the Coulter counter measurements is mainly caused by the irregular shape of dust particles in ice core samples. The irregular shape means that a new calibration routine based on standard spheres is necessary for obtaining fully comparable data. This new calibration routine gives an increased accuracy to Abakus measurements, which may improve future ice core record intercomparisons. We derived an analytical model for extracting the aspect ratio of dust particles from the difference between Abakus and Coulter counter data. For verification, we measured the aspect ratio of the same samples directly using a single-particle extinction and scattering instrument. The results demonstrate that the model is accurate enough to discern between samples of aspect ratio 0.3 and 0.4 using only the comparison of Abakus and Coulter counter data.

Prenatal diagnosis of periventricular nodular heterotopia in borderline ventriculomegaly using sonography and magnetic resonance imaging.

PubMed

Sahinoglu, Zeki; Yapicier, Ozlem; Ozcan, Nahit

2016-10-01

Periventricular nodular heterotopia (PNH) is usually missed on prenatal sonographic examinations, even on targeted scans. Irregular ventricular walls on axial view and irregular square-shaped lateral ventricles on coronal view are suggestive of PNH in the early third trimester. To achieve an early prenatal diagnosis, it is important to keep in mind the possible coexistence of PNH with brain malformations such as ventriculomegaly, posterior fossa anomalies, or agenesis of corpus callosum. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:510-513, 2016. © 2016 Wiley Periodicals, Inc.

The Particle Shape of WC Governing the Fracture Mechanism of Particle Reinforced Iron Matrix Composites.

PubMed

Li, Zulai; Wang, Pengfei; Shan, Quan; Jiang, Yehua; Wei, He; Tan, Jun

2018-06-11

In this work, tungsten carbide particles (WC p , spherical and irregular particles)-reinforced iron matrix composites were manufactured utilizing a liquid sintering technique. The mechanical properties and the fracture mechanism of WC p /iron matrix composites were investigated theoretically and experimentally. The crack schematic diagram and fracture simulation diagram of WC p /iron matrix composites were summarized, indicating that the micro-crack was initiated both from the interface for spherical and irregular WC p /iron matrix composites. However, irregular WC p had a tendency to form spherical WC p . The micro-cracks then expanded to a wide macro-crack at the interface, leading to a final failure of the composites. In comparison with the spherical WC p , the irregular WC p were prone to break due to the stress concentration resulting in being prone to generating brittle cracking. The study on the fracture mechanisms of WC p /iron matrix composites might provide a theoretical guidance for the design and engineering application of particle reinforced composites.

The peculiar shapes of Saturn's small inner moons as evidence of mergers of similar-sized moonlets

NASA Astrophysics Data System (ADS)

Leleu, A.; Jutzi, M.; Rubin, M.

2018-05-01

The Cassini spacecraft revealed the spectacular, highly irregular shapes of the small inner moons of Saturn1, ranging from the unique 'ravioli-like' forms of Pan and Atlas2,3 to the highly elongated structure of Prometheus. Closest to Saturn, these bodies provide important clues regarding the formation process of small moons in close orbits around their host planet4, but their range of irregular shapes has not been explained yet. Here, we show that the spectrum of shapes among Saturn's small moons is a natural outcome of merging collisions among similar-sized moonlets possessing physical properties and orbits that are consistent with those of the current moons. A significant fraction of such merging collisions take place either at the first encounter or after 1-2 hit-and-run events, with impact velocities in the range of 1-5 times the mutual escape velocity. Close to head-on mergers result in flattened objects with large equatorial ridges, as observed on Atlas and Pan. With slightly more oblique impact angles, collisions lead to elongated, Prometheus-like shapes. These results suggest that the current forms of the small moons provide direct evidence of the processes at the final stages of their formation, involving pairwise encounters of moonlets of comparable size4-6. Finally, we show that this mechanism may also explain the formation of Iapetus' equatorial ridge7, as well as its oblate shape8.

Weight information labels on media models reduce body dissatisfaction in adolescent girls.

PubMed

Veldhuis, Jolanda; Konijn, Elly A; Seidell, Jacob C

2012-06-01

To examine how weight information labels on variously sized media models affect (pre)adolescent girls' body perceptions and how they compare themselves with media models. We used a three (body shape: extremely thin vs. thin vs. normal weight) × three (information label: 6-kg underweight vs. 3-kg underweight vs. normal weight) experimental design in three age-groups (9-10 years, 12-13 years, and 15-16 years; n = 184). The girls completed questionnaires after exposure to media models. Weight information labels affected girls' body dissatisfaction, social comparison with media figures, and objectified body consciousness. Respondents exposed to an extremely thin body shape labeled to be of "normal weight" were most dissatisfied with their own bodies and showed highest levels of objectified body consciousness and comparison with media figures. An extremely thin body shape combined with a corresponding label (i.e., 6-kg underweight), however, induced less body dissatisfaction and less comparison with the media model. Age differences were also found to affect body perceptions: adolescent girls showed more negative body perceptions than preadolescents. Weight information labels may counteract the generally media-induced thin-body ideal. That is, when the weight labels appropriately informed the respondents about the actual thinness of the media model's body shape, girls were less affected. Weight information labels also instigated a normalization effect when a "normal-weight" label was attached to underweight-sized media models. Presenting underweight as a normal body shape, clearly increased body dissatisfaction in girls. Results also suggest age between preadolescence and adolescence as a critical criterion in responding to media models' body shape. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Method for Ultrasonic Imaging and Device for Performing the Method

NASA Technical Reports Server (NTRS)

Madaras, Eric I. (Inventor)

1997-01-01

A method for ultrasonic imaging of interior structures and flaws in a test specimen with a smooth or irregular contact surfaces, in which an ultrasonic transducer is coupled acoustically to the contact surface via a plurality of ultrasonic wave guides with equal delay times. The wave guides are thin and bendable, so they adapt to variations in the distance between the transducer and different parts of the contact surface by bending more or less. All parts of the irregular contact surface accordingly receive sound waves that are in phase, even when the contact surface is irregular, so a coherent sound wave is infused in the test specimen. The wave guides can be arranged in the form of an ultrasonic brush, with a flat head for coupling to a flat transducer, and free bristles that can be pressed against the test specimen. By bevelling the bristle ends at a suitable angle, shear mode waves can be infused into the test specimen from a longitudinal mode transducer.

Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

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

Sevastianov, L. A., E-mail: sevast@sci.pfu.edu.ru; Egorov, A. A.; Sevastyanov, A. L.

2013-02-15

Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell's equations is made to obey 'inclined' boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of 'entanglement'more » of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lueneburg lens.« less

Atmospheric Condensational Properties of Ultrafine Chain and Fractal Aerosol Particles

NASA Technical Reports Server (NTRS)

Marlow, William H.

1997-01-01

The purpose for the research sponsored by this grant was to lay the foundations for qualitative understanding and quantitative description of the equilibrium vapor pressure of water vapor over the irregularly shaped, carbonaceous particles that are present in the atmosphere. This work apparently was the first systematic treatment of the subject. Research was conducted in two complementary components: 1. Calculations were performed of the equilibrium vapor pressure of water over particles comprised of aggregates of spheres in the 50-200 nm radius range. The purposes of this work were two-fold. First, since no systematic treatment of this subject had previously been conducted, its availability would be directly useful for quantitative treatment for a limited range of atmospheric aerosols. Second, it would provide qualitative indications of the effects of highly irregular particle shape on equilibrium vapor pressure of aggregates comprised of smaller spheres.

The nature of Trojan asteroid 624 Hektor

NASA Technical Reports Server (NTRS)

Hartmann, W. K.; Cruikshank, D. P.

1978-01-01

Near-simultaneous visual and thermal IR (20-micron) photometry of the Trojan asteroid 624 Hektor is reported which was performed when the asteroid was observed nearly along its rotation axis. The results confirm and refine the low albedo and large size of this asteroid and confirm the general rotational-pole position and aspect angle predicted by Dunlap and Gehrels (1969). Hektor is found to be a truly extraordinary object in that it is larger and far more irregular in shape than other measured Trojans and far more irregular than other belt asteroids of comparable size. It is proposed that Hektor could be a partially coalesced pair of Trojan asteroids which collided with energy too low to cause complete fragmentation, thus forming a dumbbell-shaped object. A possible scenario is outlined according to which the two pre-Hektor objects were neighboring relatively large primitive spheroidal planetesimals trapped in Jupiter's Lagrangian cloud. Observational and theoretical tests of this model are suggested.

Lexical Semantics and Irregular Inflection

PubMed Central

Huang, Yi Ting; Pinker, Steven

2010-01-01

Whether a word has an irregular inflection does not depend on its sound alone: compare lie-lay (recline) and lie-lied (prevaricate). Theories of morphology, particularly connectionist and symbolic models, disagree on which nonphonological factors are responsible. We test four possibilities: (1) Lexical effects, in which two lemmas differ in whether they specify an irregular form; (2) Semantic effects, in which the semantic features of a word become associated with regular or irregular forms; (3) Morphological structure effects, in which a word with a headless structure (e.g., a verb derived from a noun) blocks access to a stored irregular form; (4) Compositionality effects, in which the stored combination of an irregular word’s meaning (e.g., the verb’s inherent aspect) with the meaning of the inflection (e.g., pastness) doesn’t readily transfer to new senses with different combinations of such meanings. In four experiments, speakers were presented with existing and novel verbs and asked to rate their past-tense forms, semantic similarities, grammatical structure, and aspectual similarities. We found (1) an interaction between semantic and phonological similarity, coinciding with reported strategies of analogizing to known verbs and implicating lexical effects; (2) weak and inconsistent effects of semantic similarity; (3) robust effects of morphological structure, and (4) robust effects of aspectual compositionality. Results are consistent with theories of language that invoke lexical entries and morphological structure, and which differentiate the mode of storage of regular and irregular verbs. They also suggest how psycholinguistic processes have shaped vocabulary structure over history. PMID:21151703

Thermal phonon transport in Si thin film with dog-leg shaped asymmetric nanostructures

NASA Astrophysics Data System (ADS)

Kage, Yuta; Hagino, Harutoshi; Yanagisawa, Ryoto; Maire, Jeremie; Miyazaki, Koji; Nomura, Masahiro

2016-08-01

Thermal phonon transport in single-crystalline Si thin films with dog-leg shaped nanostructures was investigated. Thermal conductivities for the forward and backward directions were measured and compared at 5 and 295 K by micro thermoreflectance. The Si thin film with dog-leg shaped nanostructures showed lower thermal conductivities than those of nanowires and two-dimensional phononic crystals with circular holes at the same surface-to-volume ratio. However, asymmetric thermal conductivity was not observed at small temperature gradient condition in spite of the highly asymmetric shape though the size of the pattern is within thermal phonon mean free path range. We conclude that strong temperature dependent thermal conductivity is required to observe the asymmetric thermal phonon conduction in monolithic materials with asymmetric nanostructures.

Eliminating the influence of source spectrum of white light scanning interferometry through time-delay estimation algorithm

NASA Astrophysics Data System (ADS)

Zhou, Yunfei; Cai, Hongzhi; Zhong, Liyun; Qiu, Xiang; Tian, Jindong; Lu, Xiaoxu

2017-05-01

In white light scanning interferometry (WLSI), the accuracy of profile measurement achieved with the conventional zero optical path difference (ZOPD) position locating method is closely related with the shape of interference signal envelope (ISE), which is mainly decided by the spectral distribution of illumination source. For a broadband light with Gaussian spectral distribution, the corresponding shape of ISE reveals a symmetric distribution, so the accurate ZOPD position can be achieved easily. However, if the spectral distribution of source is irregular, the shape of ISE will become asymmetric or complex multi-peak distribution, WLSI cannot work well through using ZOPD position locating method. Aiming at this problem, we propose time-delay estimation (TDE) based WLSI method, in which the surface profile information is achieved by using the relative displacement of interference signal between different pixels instead of the conventional ZOPD position locating method. Due to all spectral information of interference signal (envelope and phase) are utilized, in addition to revealing the advantage of high accuracy, the proposed method can achieve profile measurement with high accuracy in the case that the shape of ISE is irregular while ZOPD position locating method cannot work. That is to say, the proposed method can effectively eliminate the influence of source spectrum.

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis

PubMed Central

Ichikawa, Kei; Tanaka, Yoshiki; Kato, Yukihito; Horai, Rie; Tamaoki, Akeno; Ichikawa, Kazuo

2017-01-01

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces. PMID:28210504

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis.

PubMed

Takagi, Mari; Kojima, Takashi; Ichikawa, Kei; Tanaka, Yoshiki; Kato, Yukihito; Horai, Rie; Tamaoki, Akeno; Ichikawa, Kazuo

2017-01-01

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces.

Study of shale reservoir nanometer-sized pores in Member 1 of Shahejie Formation in JX area, Liaozhong sag

NASA Astrophysics Data System (ADS)

Cheng, Yong; Zhang, Yu; Wen, Yiming

2018-02-01

The microscopic pore structure is the key of the shale reservoir study; however, traditional Scanning Electron Microscopy (SEM) methods cannot identify the irregular morphology caused by mechanical polishing. In this work, Scanning Electron Microscopy combined argon ion polishing technology was taken to study the characteristics of shale reservoir pores of Member 1 of Shahejie Formation (E3s1) located in JX1-1 area of Liaozhong Sag. The results show that pores between clay platelets, intraplatelet pores within clay aggregates and organic-matter pores are very rich in the area and with good pore connectivity, so these types of pores are of great significance for oil-gas exporation. Pores between clay platelets are formed by directional or semi-directional contact between edge and surface, edge and edge or surface and surface of laminated clay minerals, whose shapes are linear, mesh, and irregular with the size of 500 nm to 5 μm. The intraplatelet pores within clay aggregates are formed in the process of the transformation and compaction of clay minerals, whose shapes are usually linear with the width of 30 to 500 nm and the length of 2 to 50 μm. The organic-matter pores are from the process of the conversion from organic matters to the hydrocarbon under thermal evolution, whose shapes are gneissic, irregular, pitted and elliptical with the size of 100 nm to 2 μm. This study is of certain guiding significance to selecting target zones, evaluating resource potential and exploring & developing of shale gas in this region.

Cubic spline anchored grid pattern algorithm for high-resolution detection of subsurface cavities by the IR-CAT method

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

Kassab, A.J.; Pollard, J.E.

An algorithm is presented for the high-resolution detection of irregular-shaped subsurface cavities within irregular-shaped bodies by the IR-CAT method. The theoretical basis of the algorithm is rooted in the solution of an inverse geometric steady-state heat conduction problem. A Cauchy boundary condition is prescribed at the exposed surface, and the inverse geometric heat conduction problem is formulated by specifying the thermal condition at the inner cavities walls, whose unknown geometries are to be detected. The location of the inner cavities is initially estimated, and the domain boundaries are discretized. Linear boundary elements are used in conjunction with cubic splines formore » high resolution of the cavity walls. An anchored grid pattern (AGP) is established to constrain the cubic spline knots that control the inner cavity geometry to evolve along the AGP at each iterative step. A residual is defined measuring the difference between imposed and computed boundary conditions. A Newton-Raphson method with a Broyden update is used to automate the detection of inner cavity walls. During the iterative procedure, the movement of the inner cavity walls is restricted to physically realistic intermediate solutions. Numerical simulation demonstrates the superior resolution of the cubic spline AGP algorithm over the linear spline-based AGP in the detection of an irregular-shaped cavity. Numerical simulation is also used to test the sensitivity of the linear and cubic spline AGP algorithms by simulating bias and random error in measured surface temperature. The proposed AGP algorithm is shown to satisfactorily detect cavities with these simulated data.« less

Two coffins and a funeral: early or late caspase activation determines two types of apoptosis induced by DNA damaging agents.

PubMed

Oropesa-Ávila, Manuel; de la Cruz-Ojeda, Patricia; Porcuna, Jesús; Villanueva-Paz, Marina; Fernández-Vega, Alejandro; de la Mata, Mario; de Lavera, Isabel; Rivero, Juan Miguel Suarez; Luzón-Hidalgo, Raquel; Álvarez-Córdoba, Mónica; Cotán, David; Zaderenko, Ana Paula; Cordero, Mario D; Sánchez-Alcázar, José A

2017-03-01

Cell cytoskeleton makes profound changes during apoptosis including the organization of an Apoptotic Microtubule Network (AMN). AMN forms a cortical structure which plays an important role in preserving plasma membrane integrity during apoptosis. Here, we examined the cytoskeleton rearrangements during apoptosis induced by camptothecin (CPT), a topoisomerase I inhibitor, in human H460 and porcine LLCPK-1α cells. Using fixed and living cell imaging, we showed that CPT induced two dose- and cell cycle-dependent types of apoptosis characterized by different cytoskeleton reorganizations, time-dependent caspase activation and final apoptotic cell morphology. In the one referred as "slow" (~h) or round-shaped, apoptosis was characterized by a slow contraction of the actinomyosin ring and late caspase activation. In "slow" apoptosis the γ-tubulin complexes were not disorganized and microtubules were not depolymerized at early stages. In contrast, "fast" (~min) or irregular-shaped apoptosis was characterized by early caspase activation followed by full contraction of the actinomyosin ring. In fast apoptosis γ-tubulin complexes were disorganized and microtubules were initially depolymerized. However, after actinomyosin contraction, microtubules were reformed adopting a cortical but irregular disposition near plasma membrane. In addition to distinctive cytoskeleton reorganization kinetics, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocytes response. Our results suggest that the knowledge and modulation of the type of apoptosis promoted by genotoxic agents may be important for deciding a better therapeutic option and predicting the immune response in cancer treatment.

Formation of functionalized nanoclusters by solvent evaporation and their effect on the physicochemical properties of dental composite resins.

PubMed

Rodríguez, Henry A; Giraldo, Luis F; Casanova, Herley

2015-07-01

The aim of this work was to study the effect of silica nanoclusters (SiNC), obtained by a solvent evaporation method and functionalized by 3-methacryloxypropyltrimethoxysilane (MPS) and MPS+octyltrimethoxysilane (OTMS) (50/50wt/wt), on the rheological, mechanical and sorption properties of urethane dimethylacrylate (UDMA)/triethylenglycol dimethacrylate (TEGDMA) (80/20wt/wt) resins blend. Silica nanoparticles (SiNP) were silanized with MPS or MPS+OTMS (50/50wt/wt) and incorporated in an UDMA-isopropanol mix to produce functionalized silica nanoclusters after evaporating the isopropanol. The effect of functionalized SiNC on resins rheological properties was determined by large and small deformation tests. Mechanical, thermal, sorption and solubility properties were evaluated for composite materials. The UDMA/TEGDMA (80/20wt/wt) resins blend with added SiNC (ca. 350nm) and functionalized with MPS showed a Newtonian flow behavior associated to their spheroidal shape, whereas the resins blend with nanoclusters silanized with MPS+OTMS (50/50wt/wt) (ca. 400nm) showed a shear-thinning behavior due to nanoclusters irregular shape. Composite materials prepared with bare silica nanoclusters showed lower compressive strength than functionalized silica nanoclusters. MPS functionalized nanoclusters showed better mechanical properties but higher water sorption than functionalized nanoclusters with both silane coupling agents, MPS and OTMS. The solvent evaporation method applied to functionalized nanoparticles showed to be an alternative way to the sinterization method for producing nanoclusters, which improved some dental composite mechanical properties and reduced water sorption. The shape of functionalized silica nanoclusters showed to have influence on the rheological properties of SiNC resin suspensions and the mechanical and sorption properties of light cured composites. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Evolutionary Patterns of Bone Histology and Bone Compactness in Xenarthran Mammal Long Bones

PubMed Central

Straehl, Fiona R.; Scheyer, Torsten M.; Forasiepi, Analía M.; MacPhee, Ross D.; Sánchez-Villagra, Marcelo R.

2013-01-01

Bone microstructure reflects physiological characteristics and has been shown to contain phylogenetic and ecological signals. Although mammalian long bone histology is receiving increasing attention, systematic examination of the main clades has not yet been performed. Here we describe the long bone microstructure of Xenarthra based on thin sections representing twenty-two species. Additionally, patterns in bone compactness of humeri and femora are investigated. The primary bone tissue of xenarthran long bones is composed of a mixture of woven, parallel-fibered and lamellar bone. The vascular canals have a longitudinal, reticular or radial orientation and are mostly arranged in an irregular manner. Concentric rows of vascular canals and laminar organization of the tissue are only found in anteater bones. The long bones of adult specimens are marked by dense Haversian bone, a feature that has been noted for most groups of mammals. In the long bones of armadillos, secondary osteons have an oblique orientation within the three-dimensional bone tissue, thus resulting in their irregular shape when the bones are sectioned transversely. Secondary remodeling is generally more extensive in large taxa than in small taxa, and this could be caused by increased loading. Lines of arrested growth are assumed to be present in all specimens, but they are restricted to the outermost layer in bones of armadillos and are often masked by secondary remodeling in large taxa. Parameters of bone compactness show a pattern in the femur that separates Cingulata and Pilosa (Folivora and Vermilingua), with cingulates having a lower compactness than pilosans. In addition, cingulates show an allometric relationship between humeral and femoral bone compactness. PMID:23874932

Study on the Unsteady Creep of Composite Beams with an Irregular Laminar Fibrous Structure Made from Nonlinear Hereditary Materials

NASA Astrophysics Data System (ADS)

Yankovskii, A. P.

2017-09-01

The creep of homogenous and hybrid composite beams of an irregular laminar fibrous structure is investigated. The beams consist of thin walls and flanges (load-carrying layers). The walls may be reinforced longitudinally or crosswise in the plane, and the load-carrying layers are reinforced in the longitudinal direction. The mechanical behavior of phase materials is described by the Rabotnov nonlinear hereditary theory of creep taking into account their possible different resistance to tension and compression. On the basis of hypotheses of the Timoshenko theory, with using the method of time steps, a problem is formulated for the inelastic bending deformation of such beams with account of the weakened resistance of their walls to the transverse shear. It is shown that, at discrete instants of time, the mechanical behavior of such structures can formally be described by the governing relations for composite beams made of nonlinear elastic anisotropic materials with a known initial stress state. The method of successive iterations, similar to the method of variable parameters of elasticity, is used to linearize the boundary-value problem at each instant of time. The bending deformation is investigated for homogeneous and reinforced cantilever and simply supported beams in creep under the action of a uniformly distributed transverse load. The cross sections of the beams considered are I-shaped. It is found that the use of the classical theory for such beams leads to the prediction of indefensibly underestimated flexibility, especially in long-term loading. It is shown that, in beams with reinforced load-carrying layers, the creep mainly develops due to the shear strains of walls. It is found that, in short- and long-term loadings of composite beams, the reinforcement structures rational by the criterion of minimum flexibility are different.

Carbide coated fibers in graphite-aluminum composites

NASA Technical Reports Server (NTRS)

Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

1975-01-01

Thin, uniform coats of titanium carbide, deposited on graphite fibers by chemical vapor deposition with thicknesses up to approximately 0.1 microns were shown to improve fiber strength significantly. For greater thicknesses, strength was degraded. The coats promote wetting of the fibers and infiltration of the fiber yarns with aluminum alloys, and act as protective barriers to inhibit reaction between the fibers and the alloys. Chemical vapor deposition was used to produce silicon carbide coats on graphite fibers. In general, the coats were nonuniform and were characterized by numerous surface irregularities. Despite these irregularities, infiltration of these fibers with aluminum alloys was good. Small graphite-aluminum composite samples were produced by vacuum hot-pressing of aluminum-infiltrated graphite yarn at temperatures above the metal liquidus.

Light beam shaping and homogenization (LSBH) by irregular microlens structure for medical applications

NASA Astrophysics Data System (ADS)

Semchishen, Vladimir A.; Mrochen, Michael; Seminogov, Vladimir N.; Panchenko, Vladislav Y.; Seiler, Theo

1998-04-01

Purpose: The increasing interest in a homogeneous Gaussian light beam profile for applications in ophthalmology e.g. photorefractive keratectomy (PRK) requests simple optical systems with low energy losses. Therefore, we developed the Light Shaping Beam Homogenizer (LSBH) working from UV up to mid-IR. Method: The irregular microlenses structure on a quartz surface was fabricated by using photolithography, chemical etching and chemical polishing processes. This created a three dimensional structure on the quartz substrate characterized in case of a Gaussian beam by random law distribution of individual irregularities tilts. The LSBH was realized for the 193 nm and the 2.94 micrometer wavelengths. Simulation results obtained by 3-D analysis for an arbitrary incident light beam were compared to experimental results. Results: The correlation to a numerical Gaussian fit is better than 94% with high uniformity for an incident beam with an intensity modulation of nearly 100%. In the far field the cross section of the beam shows always rotation symmetry. Transmittance and damage threshold of the LSBH are only dependent on the substrate characteristics. Conclusions: considering our experimental and simulation results it is possible to control the angular distribution of the beam intensity after LSBH with higher efficiency compared to diffraction or holographic optical elements.

Can we apply the MRI BI-RADS lexicon morphology descriptors on contrast-enhanced spectral mammography?

PubMed

Kamal, Rasha M; Helal, Maha H; Mansour, Sahar M; Haggag, Marwa A; Nada, Omniya M; Farahat, Iman G; Alieldin, Nelly H

2016-07-12

To assess the feasibility of using the MRI breast imaging reporting and data system (BI-RADS) lexicon morphology descriptors to characterize enhancing breast lesions identified on contrast-enhanced spectral mammography (CESM). The study is a retrospective analysis of the morphology descriptors of 261 enhancing breast lesions identified on CESM in 239 patients. We presented the morphological categorization of the included lesions into focus, mass and non-mass. Further classifications included (1) the multiplicity for "focus" category, (2) the shape, margin and internal enhancement for "mass" category and (3) the distribution and internal enhancement for "non-mass" category. Each morphology descriptor was evaluated individually (irrespective of all other descriptors) by calculating its sensitivity, specificity, positive-predictive value (PPV) and negative-predictive value (NPV) and likelihood ratios (LRs). The study included 68/261 (26.1%) benign lesions and 193/261 (73.9%) malignant lesions. Intensely enhancing foci, whether single (7/12, 58.3%) or multiple (2/12, 16.7%), were malignant. Descriptors of "irregular"-shape (PPV: 92.4%) and "non-circumscribed" margin (odds ratio: 55.2, LR positive: 4.77; p-value: <0.001) were more compatible with malignancy. Internal mass enhancement patterns showed a very low specificity (58.0%) and NPV (40.0%). Non-mass enhancement (NME) was detected in 81/261 lesions. Asymmetrical NME in 81% (n = 52/81) lesions was malignant lesions and internal enhancement patterns indicative of malignancy were the heterogeneous and clumped ones. We can apply the MRI morphology descriptors to characterize lesions on CESM, but with few expectations. In many situations, irregular-shaped, non-circumscribed masses and NME with focal, ductal or segmental distribution and heterogeneous or clumped enhancement are the most suggestive descriptors of malignant pathologies. (1) The MRI BI-RADS lexicon morphology descriptors can be applied in the characterization of enhancing lesions on CESM with a few exceptions. (2) Multiple bilateral intensely enhancing foci should not be included under the normal background parenchymal enhancement unless they are proved to be benign by biopsy. (3) Mass lesion features that indicated malignancy were irregular-shaped, spiculated and irregular margins and heterogeneous internal enhancement patterns. The rim enhancement pattern should not be considered as a descriptor of malignant lesions unless CESM is coupled with an ultrasound examination.

Effect of Substrate Roughness on Adhesion and Structural Properties of Ti-Ni Shape Memory Alloy Thin Film.

PubMed

Kim, Donghwan; Lee, Hyunsuk; Bae, Joohyeon; Jeong, Hyomin; Choi, Byeongkeun; Nam, Taehyun; Noh, Jungpil

2018-09-01

Ti-Ni shape memory alloy (SMA) thin films are very attractive material for industrial and medical applications such as micro-actuator, micro-sensors, and stents for blood vessels. An important property besides shape memory effect in the application of SMA thin films is the adhesion between the film and the substrate. When using thin films as micro-actuators or micro-sensors in MEMS, the film must be strongly adhered to the substrate. On the other hand, when using SMA thin films in medical devices such as stents, the deposited alloy thin film must be easily separable from the substrate for efficient processing. In this study, we investigated the effect of substrate roughness on the adhesion of Ti-Ni SMA thin films, as well as the structural properties and phase-transformation behavior of the fabricated films. Ti-Ni SMA thin films were deposited onto etched glass substrates with magnetron sputtering. Radio frequency plasma was used for etching the substrate. The adhesion properties were investigated through progressive scratch test. Structural properties of the films were determined via Feld emission scanning electron microscopy, X-ray diffraction measurements (XRD) and Energy-dispersive X-ray spectroscopy analysis. Phase transformation behaviors were observed with differential scanning calorimetry and low temperature-XRD. Ti-Ni SMA thin film deposited onto rough substrate provides higher adhesive strength than smooth substrate. However the roughness of the substrate has no influence on the growth and crystallization of the Ti-Ni SMA thin films.

Biocorrosion investigation of two shape memory nickel based alloys: Ni-Mn-Ga and thin film NiTi.

PubMed

Stepan, L L; Levi, D S; Gans, E; Mohanchandra, K P; Ujihara, M; Carman, G P

2007-09-01

Thin film nitinol and single crystal Ni-Mn-Ga represent two new shape memory materials with potential to be used as percutaneously placed implant devices. However, the biocompatibility of these materials has not been adequately assessed. Immersion tests were conducted on both thin film nitinol and single crystal Ni-Mn-Ga in Hank's balanced salt solution at 37 degrees C and pH 7.4. After 12 h, large pits were found on the Ni-Mn-Ga samples while thin film nitinol displayed no signs of corrosion. Further electrochemical tests on thin film nitinol samples revealed breakdown potentials superior to a mechanically polished nitinol disc. These results suggest that passivation or electropolishing of thin film nitinol maybe unnecessary to promote corrosion resistance.

Stand development 18 years after gap creation in a uniform Douglas-fir plantation

Treesearch

Robert O. Curtis; Constance A. Harrington; Leslie C. Brodie

2017-01-01

This report gives early results, 18 years after treatment and 30 years after planting, from a trial of early thinning and gap creation intended to increase biodiversity in a very uniform extensive Douglas-fir plantation. Gap creation has introduced canopy irregularity and a substantial hemlock component into what was originally a very uniform pure Douglas-fir...

Impaired color naming of food and body shape words: weight phobia or distinct affective state?

PubMed

Green, M W; Elliman, N A; Rogers, P J; Welch, D A

1997-01-01

The current study investigated whether a concern with body shape and weight represents a distinct affective state, or whether it is better conceptualized as a highly specific form of anxiety. The color-naming performance of women with a high Drive for Thinness score was examined under three experimental conditions: when a photograph of chocolate was present, when actual chocolate was present, and a control condition. High Drive for Thinness subjects demonstrated relatively impaired color naming of body shape words in the picture condition, but not in the food or control conditions. Although there was a significant impairment in the color naming of food words, this was unaffected by condition or degree of Drive for Thinness. The results are interpreted as supporting an analogy between weight/body shape concerns and subclinical phobic anxiety.

IMAGING DIAGNOSIS-ULTRASONOGRAPHIC APPEARANCE OF SKELETAL MUSCLE METASTASES IN A DOG WITH HEMANGIOSARCOMA.

PubMed

Fabbi, Martina; Di Palma, Stefano; Manfredi, Sabrina; Gnudi, Giacomo; Miduri, Francesca; Daga, Eleonora; Melis, Gabriele Costantino; Bianchi, Ezio; Voccia, Simone; Volta, Antonella

2017-11-01

A 13-year-old spayed female German shepherd dog was presented for acute onset of lethargy, anorexia, and disseminated erythematous skin lesions. Thoracic radiographs and abdominal ultrasonographic findings were consistent with metastatic hemangiosarcoma. Multiple, ill-defined, irregularly shaped hypoechoic nodules were also detected within the thoracic and abdominal wall. Hemangiosarcoma metastases to the skeletal muscle were confirmed based on histopathological examination. Multivisceral involvement was also confirmed by necropsy. Metastatic neoplasia should be considered as a differential diagnosis for dogs with ill-defined, irregular, hypoechoic, intramuscular nodules. © 2016 American College of Veterinary Radiology.

An emerging disease in blueberry

USDA-ARS?s Scientific Manuscript database

A new disorder was observed on southern highbush blueberry (Vaccinium corymbosum interspecific hybrids) in several southeastern states. Symptoms included irregularly shaped circular spots or blotches with green centers on the top and bottom of leaves. The disease was reported initially in the state ...

Origin of three-dimensional shapes of chondrules. I. Hydrodynamics simulations of rotating droplet exposed to high-velocity rarefied gas flow

NASA Astrophysics Data System (ADS)

Miura, Hitoshi; Nakamoto, Taishi; Doi, Masao

2008-09-01

The origin of three-dimensional shapes of chondrules is an important information to identify their formation mechanism in the early solar nebula. The measurement of their shapes by using X-ray computed topography suggested that they are usually close to perfect spheres, however, some of them have rugby-ball-like (prolate) shapes [Tsuchiyama, A., Shigeyoshi, R., Kawabata, T., Nakano, T., Uesugi, K., Shirono, S., 2003. Lunar Planet. Sci. 34, 1271-1272]. We considered that the prolate shapes reflect the deformations of chondrule precursor dust particles when they are heated and melted in the high velocity gas flow. In order to reveal the origin of chondrule shapes, we carried out the three-dimensional hydrodynamics simulations of a rotating molten chondrule exposed to the gas flow in the framework of the shock-wave heating model for chondrule formation. We adopted the gas ram pressure acting on the chondrule surface of p=10 dyncm in a typical shock wave. Considering that the chondrule precursor dust particle has an irregular shape before melting, the ram pressure causes a net torque to rotate the particle. The estimated angular velocity is ω=140 rads for the precursor radius of r=1 mm, though it has a different value depending on the irregularity of the shape. In addition, the rotation axis is likely to be perpendicular to the direction of the gas flow. Our calculations showed that the rotating molten chondrule elongates along the rotation axis, in contrast, shrinks perpendicularly to it. It is a prolate shape. The reason why the molten chondrule is deformed to a prolate shape was clearly discussed. Our study gives a complementary constraint for chondrule formation mechanisms, comparing with conventional chemical analyses and dynamic crystallization experiments that have mainly constrained the thermal evolutions of chondrules.

Quantitative morphometric analysis of hepatocellular carcinoma: development of a programmed algorithm and preliminary application.

PubMed

Yap, Felix Y; Bui, James T; Knuttinen, M Grace; Walzer, Natasha M; Cotler, Scott J; Owens, Charles A; Berkes, Jamie L; Gaba, Ron C

2013-01-01

The quantitative relationship between tumor morphology and malignant potential has not been explored in liver tumors. We designed a computer algorithm to analyze shape features of hepatocellular carcinoma (HCC) and tested feasibility of morphologic analysis. Cross-sectional images from 118 patients diagnosed with HCC between 2007 and 2010 were extracted at the widest index tumor diameter. The tumor margins were outlined, and point coordinates were input into a MATLAB (MathWorks Inc., Natick, Massachusetts, USA) algorithm. Twelve shape descriptors were calculated per tumor: the compactness, the mean radial distance (MRD), the RD standard deviation (RDSD), the RD area ratio (RDAR), the zero crossings, entropy, the mean Feret diameter (MFD), the Feret ratio, the convex hull area (CHA) and perimeter (CHP) ratios, the elliptic compactness (EC), and the elliptic irregularity (EI). The parameters were correlated with the levels of alpha-fetoprotein (AFP) as an indicator of tumor aggressiveness. The quantitative morphometric analysis was technically successful in all cases. The mean parameters were as follows: compactness 0.88±0.086, MRD 0.83±0.056, RDSD 0.087±0.037, RDAR 0.045±0.023, zero crossings 6±2.2, entropy 1.43±0.16, MFD 4.40±3.14 cm, Feret ratio 0.78±0.089, CHA 0.98±0.027, CHP 0.98±0.030, EC 0.95±0.043, and EI 0.95±0.023. MFD and RDAR provided the widest value range for the best shape discrimination. The larger tumors were less compact, more concave, and less ellipsoid than the smaller tumors (P < 0.0001). AFP-producing tumors displayed greater morphologic irregularity based on several parameters, including compactness, MRD, RDSD, RDAR, entropy, and EI (P < 0.05 for all). Computerized HCC image analysis using shape descriptors is technically feasible. Aggressively growing tumors have wider diameters and more irregular margins. Future studies will determine further clinical applications for this morphologic analysis.

Thin Cu film resistivity using four probe techniques: Effect of film thickness and geometrical shapes

NASA Astrophysics Data System (ADS)

Choudhary, Sumita; Narula, Rahul; Gangopadhyay, Subhashis

2018-05-01

Precise measurement of electrical sheet resistance and resistivity of metallic thin Cu films may play a significant role in temperature sensing by means of resistivity changes which can further act as a safety measure of various electronic devices during their operation. Four point probes resistivity measurement is a useful approach as it successfully excludes the contact resistance between the probes and film surface of the sample. Although, the resistivity of bulk samples at a particular temperature mostly depends on its materialistic property, however, it may significantly differ in the case of thin films, where the shape and thickness of the sample can significantly influence on it. Depending on the ratio of the film thickness to probe spacing, samples are usually classified in two segments such as (i) thick films or (ii) thin films. Accordingly, the geometric correction factors G can be related to the sample resistivity r, which has been calculated here for thin Cu films of thickness up to few 100 nm. In this study, various rectangular shapes of thin Cu films have been used to determine the shape induced geometric correction factors G. An expressions for G have been obtained as a function of film thickness t versus the probe spacing s. Using these expressions, the correction factors have been plotted separately for each cases as a function of (a) film thickness for fixed linear probe spacing and (b) probe distance from the edge of the film surface for particular thickness. Finally, we compare the experimental results of thin Cu films of various rectangular geometries with the theoretical reported results.

Advanced light-trapping effect of thin-film solar cell with dual photonic crystals

NASA Astrophysics Data System (ADS)

Zhang, Anjun; Guo, Zhongyi; Tao, Yifei; Wang, Wei; Mao, Xiaoqin; Fan, Guanghua; Zhou, Keya; Qu, Shiliang

2015-05-01

A thin-film solar cell with dual photonic crystals has been proposed, which shows an advanced light-trapping effect and superior performance in ultimate conversion efficiency (UCE). The shapes of nanocones have been optimized and discussed in detail by self-definition. The optimized shape of nanocone arrays (NCs) is a parabolic shape with a nearly linearly graded refractive index (GRI) profile from the air to Si, and the corresponding UCE is 30.3% for the NCs with a period of 300 nm and a thickness of only 2 μm. The top NCs and bottom NCs of the thin film have been simulated respectively to investigate their optimized shapes, and their separate contributions to the light harvest have also been discussed fully. The height of the top NCs and bottom NCs will also influence the performances of the thin-film solar cell greatly, and the result indicates that the unconformal NCs have better light-trapping ability with an optimal UCE of 32.3% than the conformal NCs with an optimal UCE of 30.3%.

Nonflat equilibrium liquid shapes on flat surfaces.

PubMed

Starov, Victor M

2004-01-15

The hydrostatic pressure in thin liquid layers differs from the pressure in the ambient air. This difference is caused by the actions of surface forces and capillary pressure. The manifestation of the surface force action is the disjoining pressure, which has a very special S-shaped form in the case of partial wetting (aqueous thin films and thin films of aqueous electrolyte and surfactant solutions, both free films and films on solid substrates). In thin flat liquid films the disjoining pressure acts alone and determines their thickness. However, if the film surface is curved then both the disjoining and the capillary pressures act simultaneously. In the case of partial wetting their simultaneous action results in the existence of nonflat equilibrium liquid shapes. It is shown that in the case of S-shaped disjoining pressure isotherm microdrops, microdepressions, and equilibrium periodic films exist on flat solid substrates. Criteria are found for both the existence and the stability of these nonflat equilibrium liquid shapes. It is shown that a transition from thick films to thinner films can go via intermediate nonflat states, microdepressions and periodic films, which both can be more stable than flat films within some range of hydrostatic pressure. Experimental investigations of shapes of the predicted nonflat layers can open new possibilities of determination of disjoining pressure in the range of thickness in which flat films are unstable.

High Performance Piezoelectric Thin Films for Shape Control in Large Inflatable Structures

NASA Technical Reports Server (NTRS)

Neurgaonkar, R. R.; Nelson, J. G.

1999-01-01

The objective of this research and development program was to develop PbZr(1-x)Ti(x)O3 (PZT) and Pb(1-x)Ba(x)Nb2O6 (PBN) materials with large piezoelectric response which are suitable for shape control in large inflatable structures. Two approaches were to be considered: (1) direct deposition of PZT and PBN films on flexible plastic or thin metal foil substrates, and (2) deposition on Si followed by fabrication of hybrid structures on mylar or kapton. Testing in shape control concepts was carried out at JPL and based on their results, the required modifications were made in the final film compositions and deposition techniques. The program objective was to identify and then optimize piezoelectric materials for NASA shape control applications. This involved the bulk piezoelectric and photovoltaic responses and the compatibility of the thin films with appropriate substrate structures. Within the PZT system, Rockwell has achieved the highest reported piezoelectric coefficient (d(sub 33) greater than 100 pC/N) of any ceramic composition. We used this experience in piezoelectric technology to establish compositions that can effectively address the issues of this program. The performance of piezoelectric thin films depends directly on d(sub ij) and Epsilon. The challenge was to find PZT compositions that maintained high d(sub ij) and Epsilon, while also exhibiting a large photovoltaic effect and integrate thin films of this composition into the system structure necessary to meet shape control applications. During the course of this program, several PZT and PLZT compositions were identified that meet these requirements. Two such compositions were successfully used in electrical and optical actuation studies of thin film structures.

High Performance Piezoelectric Thin Films for Shape Control in Large Inflatable Structures

NASA Technical Reports Server (NTRS)

Neurgaonkar, R. R.; Nelson, J. G.

1999-01-01

The objective of this research and development program was to develop PbZr(1-x)Ti(x)O3 (PZT) and Pb(1-x)Ba(x)Nb2O6 (PBN) materials with large piezoelectric response which are suitable for shape control in large inflatable structures. Two approaches were to be considered: (1) direct deposition of PZT and PBN films on flexible plastic or thin metal foil substrates, and (2) deposition on Si followed by fabrication of hybrid structures on mylar or kapton. Testing in shape control concepts was carried out at JPL and based on their results, the required modifications were made in the final film compositions and deposition techniques. The program objective was to identify and then optimize piezoelectric materials for NASA shape control applications. This involved the bulk piezoelectric and photovoltaic responses and the compatibility of the thin films with appropriate substrate structures. Within the PZT system, Rockwell has achieved the highest reported piezoelectric coefficient (d(sub 33) greater than 100 pC/N) of any ceramic composition. We used this experience in piezoelectric technology to establish compositions that can effectively address the issues of this program. The performance of piezoelectric thin films depends directly on d(sub ij) and epsilin. The challenge was to find PZT compositions that maintained high d(sub ij) and epsilon, while also exhibiting a large photovoltaic effect and integrate thin films of this composition into the system structure necessary to meet shape control applications. During the course of this program, several PZT and PLZT compositions were identified that meet these requirements. Two such compositions were successfully used in electrical and optical actuation studies of thin film structures.

Body satisfaction and pressure to be thin in younger and older Muslim and non-Muslim women: the role of Western and non-Western dress preferences.

PubMed

Dunkel, Trisha M; Davidson, Denise; Qurashi, Shaji

2010-01-01

Younger and older Muslim and non-Muslim women living in the United States completed questionnaires about body satisfaction and their internalization of Western standards of beauty (thin-ideal). Younger Muslim women wearing non-Western clothing and a head veil were significantly less likely to express drive for thinness or pressure to attain a thin-ideal standard of beauty than women wearing Western dress or younger women wearing non-Western dress without a head veil. Older women, while expressing greater discrepancy between their ideal body shape and their current body shape, and less satisfaction with their bodies than younger women, reported less drive for thinness and less pressure to attain the Western thin-ideal standard of beauty than younger women. These results are discussed in terms of how factors such as age and religion may serve as protective factors against a strong or unhealthy drive for thinness or thin-ideal standard. Copyright 2009 Elsevier Ltd. All rights reserved.

Effect of Particle Morphology on the Reactivity of Explosively Dispersed Titanium Particles

NASA Astrophysics Data System (ADS)

Frost, David L.; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2009-12-01

The effect of particle morphology on the reaction of titanium (Ti) particles explosively dispersed during the detonation of either cylindrical or spherical charges has been investigated experimentally. The explosive charges consisted of packed beds of Ti particles saturated with nitromethane. The reaction behaviour of irregularly-shaped Ti particles in three size ranges is compared with tests with spherical Ti particles. The particle reaction is strongly dependent on particle morphology, e.g., 95 μm spherical Ti particles failed to ignite (in cylinders up to 49 mm in dia), whereas similarly sized irregular Ti particles readily ignited. For irregular particles, the uniformity of ignition on the particle cloud surface was almost independent of particle size, but depended on charge diameter. As the charge diameter was reduced, ignition in the conically expanding particle cloud occurred only at isolated spots or bands. For spherical charges, whereas large irregular Ti particles ignited promptly and uniformly throughout the particle cloud, the smallest particles dispersed nonuniformly and ignition occurred at isolated locations after a delay. Hence the charge geometry, as well as particle morphology, influences the reaction behaviour of the particles.

Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

PubMed Central

Zuluaga-Ramírez, Pablo; Frövel, Malte; Belenguer, Tomás; Salazar, Félix

2015-01-01

This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. PMID:28793655

Characterization of dust from blast furnace cast house de-dusting.

PubMed

Lanzerstorfer, Christof

2017-10-01

During casting of liquid iron and slag, a considerable amount of dust is emitted into the cast house of a blast furnace (BF). Usually, this dust is extracted via exhaust hoods and subsequently separated from the ventilation air. In most BFs the cast house dust is recycled. In this study a sample of cast house dust was split by air classification into five size fractions, which were then analysed. Micrographs showed that the dominating particle type in all size fractions is that of single spherical-shaped particles. However, some irregular-shaped particles were also found and in the finest size fraction also some agglomerates were present. Almost spherical particles consisted of Fe and O, while highly irregular-shaped particles consisted of C. The most abundant element was Fe, followed by Ca and C. These elements were distributed relatively uniformly in the size fractions. As, Cd, Cu, K, Pb, S, Sb and Zn were enriched significantly in the fine size fractions. Thus, air classification would be an effective method for improved recycling. By separating a small fraction of fines (about 10-20%), a reduction of the mass of Zn in the coarse dust recycled in the range of 40-55% would be possible.

Baseline-dependent sampling and windowing for radio interferometry: data compression, field-of-interest shaping, and outer field suppression

NASA Astrophysics Data System (ADS)

Atemkeng, M.; Smirnov, O.; Tasse, C.; Foster, G.; Keimpema, A.; Paragi, Z.; Jonas, J.

2018-07-01

Traditional radio interferometric correlators produce regular-gridded samples of the true uv-distribution by averaging the signal over constant, discrete time-frequency intervals. This regular sampling and averaging then translate to be irregular-gridded samples in the uv-space, and results in a baseline-length-dependent loss of amplitude and phase coherence, which is dependent on the distance from the image phase centre. The effect is often referred to as `decorrelation' in the uv-space, which is equivalent in the source domain to `smearing'. This work discusses and implements a regular-gridded sampling scheme in the uv-space (baseline-dependent sampling) and windowing that allow for data compression, field-of-interest shaping, and source suppression. The baseline-dependent sampling requires irregular-gridded sampling in the time-frequency space, i.e. the time-frequency interval becomes baseline dependent. Analytic models and simulations are used to show that decorrelation remains constant across all the baselines when applying baseline-dependent sampling and windowing. Simulations using MeerKAT telescope and the European Very Long Baseline Interferometry Network show that both data compression, field-of-interest shaping, and outer field-of-interest suppression are achieved.

Holcophloeus caldarai (Coleoptera: Curculionidae: Holcorhinini) a new weevil species from Morocco.

PubMed

Borovec, Roman; KoŠŤÁl, Michael; BÁborskÁ, Zuzana

2018-04-05

Holcophloeus caldarai sp. n. is described as a fifth species of the genus from central Morocco. The new species differs from all other species of the genus and, generally the entire tribe, by unique irregularly star-shaped appressed scales.

Skin aging: in vivo microscopic assessment of epidermal and dermal changes by means of confocal microscopy.

PubMed

Longo, Caterina; Casari, Alice; Beretti, Francesca; Cesinaro, Anna Maria; Pellacani, Giovanni

2013-03-01

Skin aging is thought to be a complex biological process that is traditionally classified as intrinsic and extrinsic aging. Several clinical score and instrumental devices have been applied to obtain a precise assessment of skin aging. Among them, confocal microscopy has emerged as a new technique capable of assessing cytoarchitectural changes with a nearly histopathologic resolution. We sought to determine the microscopic skin changes occurring on the face in different age groups by means of confocal microscopy. The skin of the cheek in 63 volunteers belonging to distinct age groups was analyzed by confocal microscopy. In 4 cases, routine histopathology was performed on site-matched surplus areas from routine excisions for obtaining a better comparison with confocal findings. Young skin was characterized by regular polygonal keratinocytes and thin reticulated collagen fibers. With aging, more irregularly shaped keratinocytes and areas with unevenly distributed pigmentation and increased compactness of collagen fibers were observed. In the elderly, thinning of the epidermis, marked keratinocyte alterations, and huddles of collagen and curled fibers, corresponding to elastosis, were present. A side-by-side correlation between confocal descriptors and histopathologic aspects has been provided in a few cases. Reticular dermal changes cannot be assessed because of the limited depth laser penetration. Confocal microscopy was successfully applied to identify in vivo skin changes occurring in aged skin at both the epidermal and dermal levels at histopathologic resolution. This offers the possibility to test cosmetic product efficacy and to identify early signs of sun damage. Copyright © 2011 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Thin-skinned deformation of sedimentary rocks in Valles Marineris, Mars

USGS Publications Warehouse

Metz, Joannah; Grotzinger, John P.; Okubo, Chris; Milliken, Ralph

2010-01-01

Deformation of sedimentary rocks is widespread within Valles Marineris, characterized by both plastic and brittle deformation identified in Candor, Melas, and Ius Chasmata. We identified four deformation styles using HiRISE and CTX images: kilometer-scale convolute folds, detached slabs, folded strata, and pull-apart structures. Convolute folds are detached rounded slabs of material with alternating dark- and light-toned strata and a fold wavelength of about 1 km. The detached slabs are isolated rounded blocks of material, but they exhibit only highly localized evidence of stratification. Folded strata are composed of continuously folded layers that are not detached. Pull-apart structures are composed of stratified rock that has broken off into small irregularly shaped pieces showing evidence of brittle deformation. Some areas exhibit multiple styles of deformation and grade from one type of deformation into another. The deformed rocks are observed over thousands of kilometers, are limited to discrete stratigraphic intervals, and occur over a wide range in elevations. All deformation styles appear to be of likely thin-skinned origin. CRISM reflectance spectra show that some of the deformed sediments contain a component of monohydrated and polyhydrated sulfates. Several mechanisms could be responsible for the deformation of sedimentary rocks in Valles Marineris, such as subaerial or subaqueous gravitational slumping or sliding and soft sediment deformation, where the latter could include impact-induced or seismically induced liquefaction. These mechanisms are evaluated based on their expected pattern, scale, and areal extent of deformation. Deformation produced from slow subaerial or subaqueous landsliding and liquefaction is consistent with the deformation observed in Valles Marineris.

A morphological analysis of the transition between the embryonic primitive intestine and yolk sac in bovine embryos and fetuses.

PubMed

Mançanares, Celina A F; Leiser, Rudolf; Favaron, Phelipe O; Carvalho, Ana F; Oliveira, Vanessa C De; Santos, José M Dos; Ambrósio, Carlos E; Miglino, Maria A

2013-07-01

The yolk sac (YS) is the main source of embryonic nutrition during the period when the placenta has not yet formed. It is also responsible for hematopoiesis because the blood cells develop from it as part of the primitive embryonic circulation. The objective of this study was to characterize the transitional area between the YS and primitive gut using the techniques of light microscopy, transmission electron microscopy, and immunohistochemistry to detect populations of pluripotent cells by labeling with Oct4 antibody. In all investigated embryos, serial sections were made to permit the identification of this small, restricted area. We identified the YS connection with the primitive intestine and found that it is composed of many blood islands, which correspond to the vessels covered by vitelline and mesenchymal cells. We identified large numbers of hemangioblasts inside the vessels. The mesenchymal layer was thin and composed of elongated cells, and the vitelline endodermal membrane was composed of large, mono- or binucleated cells. The epithelium of the primitive intestine comprised stratified columnar cells and undifferentiated mesenchymal cells. The transitional area between the YS and the primitive intestine was very thin and composed of cells with irregular shapes, which formed a delicate lumen containing hemangioblasts. In the mesenchyme of the transitional area, there were a considerable number of small vessels containing hemangioblasts. Using Oct4 as a primary antibody, we identified positive cells in the metanephros, primordial gonad, and hepatic parenchyma as well as in YS cells, suggesting that these regions contain populations of pluripotent cells. Copyright © 2013 Wiley Periodicals, Inc.

Microstructure study of ZnO thin films on Si substrate grown by MOCVD

NASA Astrophysics Data System (ADS)

Huang, Jingyun; Ye, Zhizhen; Lu, Huanming; Wang, Lei; Zhao, Binghui; Li, Xianhang

2007-08-01

The microstructure of zinc oxide thin films on silicon substrates grown by metalorganic chemical vapour deposition (MOCVD) was characterized. The cross-sectional bright-field transmission electron microscopy (TEM) image showed that small ZnO columnar grains were embedded into large columnar grains, and the selected-area electron diffraction pattern showed that the ZnO/Si thin films were nearly c-axis oriented. The deviation angle along the ZnO (0 0 0 1) direction with respect to the growth direction of Si (1 0 0) was no more than 5°. The [0 0 0 1]-tilt grain boundaries in ZnO/Si thin films were investigated symmetrically by plan-view high resolution TEM. The boundaries can be classified into three types: low-angle boundaries described as an irregular array of edge dislocations, boundaries of near 30° angle with (1\\,0\\,\\bar{1}\\,0) facet structures and large-angle boundaries with symmetric structure which could be explained by a low Σ coincident site lattice structure mode. The research was useful to us for finding optimized growth conditions to improve ZnO/Si thin film quality.

Tree branch-shaped cupric oxide for highly effective photoelectrochemical water reduction

NASA Astrophysics Data System (ADS)

Jang, Youn Jeong; Jang, Ji-Wook; Choi, Sun Hee; Kim, Jae Young; Kim, Ju Hun; Youn, Duck Hyun; Kim, Won Yong; Han, Suenghoon; Sung Lee, Jae

2015-04-01

Highly efficient tree branch-shaped CuO photocathodes are fabricated using the hybrid microwave annealing process with a silicon susceptor within 10 minutes. The unique hierarchical, one-dimensional structure provides more facile charge transport, larger surface areas, and increased crystallinity and crystal ordering with less defects compared to irregular-shaped CuO prepared by conventional thermal annealing. As a result, the photocathode fabricated with the tree branch-shaped CuO produces an unprecedently high photocurrent density of -4.4 mA cm-2 at 0 VRHE under AM 1.5 G simulated sunlight compared to -1.44 mA cm-2 observed for a photocathode fabricated by thermal annealing. It is also confirmed that stoichiometric hydrogen and oxygen are produced from photoelectrochemical water splitting on the tree branch-shaped CuO photocathode and a platinum anode.Highly efficient tree branch-shaped CuO photocathodes are fabricated using the hybrid microwave annealing process with a silicon susceptor within 10 minutes. The unique hierarchical, one-dimensional structure provides more facile charge transport, larger surface areas, and increased crystallinity and crystal ordering with less defects compared to irregular-shaped CuO prepared by conventional thermal annealing. As a result, the photocathode fabricated with the tree branch-shaped CuO produces an unprecedently high photocurrent density of -4.4 mA cm-2 at 0 VRHE under AM 1.5 G simulated sunlight compared to -1.44 mA cm-2 observed for a photocathode fabricated by thermal annealing. It is also confirmed that stoichiometric hydrogen and oxygen are produced from photoelectrochemical water splitting on the tree branch-shaped CuO photocathode and a platinum anode. Electronic supplementary information (ESI) available: The detailed schematic diagram for the HMA process, XRD results, the temperature profile during HMA, derivative XANES results, TEM images, J-V curves, lists of previously reported copper oxide photocathode, and parameters extracted from EIS. See DOI: 10.1039/c5nr00208g

Wound stability and surgically induced corneal astigmatism after transconjunctival single-plane sclerocorneal incision cataract surgery.

PubMed

Hayashi, Ken; Ogawa, Soichiro; Yoshida, Motoaki; Yoshimura, Koichi

2017-01-01

To compare intraocular pressure (IOP) immediately after cataract surgery, and surgically induced corneal astigmatism (SIA) and corneal shape changes between eyes with transconjunctival single-plane sclerocorneal incisions (TSSIs) and eyes with clear corneal incisions (CCIs). Bilateral eyes of 64 patients undergoing phacoemulsification were randomized to undergo 2.4-mm temporal TSSI or CCI. IOP was measured preoperatively, and in the immediate postoperative periods. SIA was determined using vector analysis, and corneal shape changes and irregular astigmatism were evaluated using a videokeratography preoperatively, and in the early postoperative periods. Wound hydration was performed in 23 eyes (35.9 %) of the TSSI group and in 60 (93.8 %) of the CCI group (P < 0.0001). Mean IOP was significantly higher in the TSSI group than in the CCI group at 30, 60, and 120 min postoperatively (P ≤ 0.0179). SIA tended to be smaller in the TSSI group than the CCI group, but the difference was not significant. The higher order irregular astigmatism was smaller in the TSSI group than in the CCI group at 2 days (P = 0.0312). The videokeratography revealed a wound-related flattening postoperatively in both groups; this change disappeared within 4 weeks in the TSSI group, whereas it persisted until 12 weeks in the CCI group. IOP was significantly higher immediately after TSSI than after CCI and required less wound hydration, suggesting better stability with TSSI. Higher order irregular astigmatism and wound-related corneal flattening were smaller after TSSI than after CCI in the early periods, suggesting that fewer corneal shape changes with TSSI.

Validation of 3D documentation of palatal soft tissue shape, color, and irregularity with intraoral scanning.

PubMed

Deferm, Julie T; Schreurs, Ruud; Baan, Frank; Bruggink, Robin; Merkx, Matthijs A W; Xi, Tong; Bergé, Stefaan J; Maal, Thomas J J

2018-04-01

The purpose of this study was to assess the feasibility of 3D intraoral scanning for documentation of palatal soft tissue by evaluating the accuracy of shape, color, and curvature. Intraoral scans of ten participants' upper dentition and palate were acquired with the TRIOS® 3D intraoral scanner by two observers. Conventional impressions were taken and digitized as a gold standard. The resulting surface models were aligned using an Iterative Closest Point approach. The absolute distance measurements between the intraoral models and the digitized impression were used to quantify the trueness and precision of intraoral scanning. The mean color of the palatal soft tissue was extracted in HSV (hue, saturation, value) format to establish the color precision. Finally, the mean curvature of the surface models was calculated and used for surface irregularity. Mean average distance error between the conventional impression models and the intraoral models was 0.02 ± 0.07 mm (p = 0.30). Mean interobserver color difference was - 0.08 ± 1.49° (p = 0.864), 0.28 ± 0.78% (p = 0.286), and 0.30 ± 1.14% (p = 0.426) for respectively hue, saturation, and value. The interobserver differences for overall and maximum surface irregularity were 0.01 ± 0.03 and 0.00 ± 0.05 mm. This study supports the hypothesis that the intraoral scan can perform a 3D documentation of palatal soft tissue in terms of shape, color, and curvature. An intraoral scanner can be an objective tool, adjunctive to the clinical examination of the palatal tissue.

Pulmonary tumor measurements from x-ray computed tomography in one, two, and three dimensions.

PubMed

Villemaire, Lauren; Owrangi, Amir M; Etemad-Rezai, Roya; Wilson, Laura; O'Riordan, Elaine; Keller, Harry; Driscoll, Brandon; Bauman, Glenn; Fenster, Aaron; Parraga, Grace

2011-11-01

We evaluated the accuracy and reproducibility of three-dimensional (3D) measurements of lung phantoms and patient tumors from x-ray computed tomography (CT) and compared these to one-dimensional (1D) and two-dimensional (2D) measurements. CT images of three spherical and three irregularly shaped tumor phantoms were evaluated by three observers who performed five repeated measurements. Additionally, three observers manually segmented 29 patient lung tumors five times each. Follow-up imaging was performed for 23 tumors and response criteria were compared. For a single subject, imaging was performed on nine occasions over 2 years to evaluate multidimensional tumor response. To evaluate measurement accuracy, we compared imaging measurements to ground truth using analysis of variance. For estimates of precision, intraobserver and interobserver coefficients of variation and intraclass correlations (ICC) were used. Linear regression and Pearson correlations were used to evaluate agreement and tumor response was descriptively compared. For spherical shaped phantoms, all measurements were highly accurate, but for irregularly shaped phantoms, only 3D measurements were in high agreement with ground truth measurements. All phantom and patient measurements showed high intra- and interobserver reproducibility (ICC >0.900). Over a 2-year period for a single patient, there was disagreement between tumor response classifications based on 3D measurements and those generated using 1D and 2D measurements. Tumor volume measurements were highly reproducible and accurate for irregular, spherical phantoms and patient tumors with nonuniform dimensions. Response classifications obtained from multidimensional measurements suggest that 3D measurements provide higher sensitivity to tumor response. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

Tactile Imaging of an Imbedded Palpable Structure for Breast Cancer Screening

PubMed Central

2015-01-01

Apart from texture, the human finger can sense palpation. The detection of an imbedded structure is a fine balance between the relative stiffness of the matrix, the object, and the device. If the device is too soft, its high responsiveness will limit the depth to which the imbedded structure can be detected. The sensation of palpation is an effective procedure for a physician to examine irregularities. In a clinical breast examination (CBE), by pressing over 1 cm2 area, at a contact pressure in the 70–90 kPa range, the physician feels cancerous lumps that are 8- to 18-fold stiffer than surrounding tissue. Early detection of a lump in the 5–10 mm range leads to an excellent prognosis. We describe a thin-film tactile device that emulates human touch to quantify CBE by imaging the size and shape of 5–10 mm objects at 20 mm depth in a breast model using ∼80 kPa pressure. The linear response of the device allows quantification where the greyscale corresponds to the relative local stiffness. The (background) signal from <2.5-fold stiffer objects at a size below 2 mm is minimal. PMID:25148477

Atomisation and droplet formation mechanisms in a model two-phase mixing layer

NASA Astrophysics Data System (ADS)

Zaleski, Stephane; Ling, Yue; Fuster, Daniel; Tryggvason, Gretar

2017-11-01

We study atomization in a turbulent two-phase mixing layer inspired by the Grenoble air-water experiments. A planar gas jet of large velocity is emitted on top of a planar liquid jet of smaller velocity. The density ratio and momentum ratios are both set at 20 in the numerical simulation in order to ease the simulation. We use a Volume-Of-Fluid method with good parallelisation properties, implemented in our code http://parissimulator.sf.net. Our simulations show two distinct droplet formation mechanisms, one in which thin liquid sheets are punctured to form rapidly expanding holes and the other in which ligaments of irregular shape form and breakup in a manner similar but not identical to jets in Rayleigh-Plateau-Savart instabilities. Observed distributions of particle sizes are extracted for a sequence of ever more refined grids, the largest grid containing approximately eight billion points. Although their accuracy is limited at small sizes by the grid resolution and at large size by statistical effects, the distributions overlap in the central region. The observed distributions are much closer to log normal distributions than to gamma distributions as is also the case for experiments.

Splash control of drop impacts with geometric targets.

PubMed

Juarez, Gabriel; Gastopoulos, Thomai; Zhang, Yibin; Siegel, Michael L; Arratia, Paulo E

2012-02-01

Drop impacts on solid and liquid surfaces exhibit complex dynamics due to the competition of inertial, viscous, and capillary forces. After impact, a liquid lamella develops and expands radially, and under certain conditions, the outer rim breaks up into an irregular arrangement of filaments and secondary droplets. We show experimentally that the lamella expansion and subsequent breakup of the outer rim can be controlled by length scales that are of comparable dimension to the impacting drop diameter. Under identical impact parameters (i.e., fluid properties and impact velocity) we observe unique splashing dynamics by varying the target cross-sectional geometry. These behaviors include (i) geometrically shaped lamellae and (ii) a transition in splashing stability, from regular to irregular splashing. We propose that regular splashes are controlled by the azimuthal perturbations imposed by the target cross-sectional geometry and that irregular splashes are governed by the fastest-growing unstable Plateau-Rayleigh mode.

Differentiation of nonneoplastic and neoplastic gallbladder polyps 1 cm or bigger with multi-detector row computed tomography.

PubMed

Park, Ko Woon; Kim, Seong Hyun; Choi, Seong Ho; Lee, Won Jae

2010-01-01

To evaluate useful computed tomographic features to differentiate nonneoplastic and neoplastic gallbladder polyps 1 cm or bigger. Thirty-one patients with 32 nonneoplastic polyps and 67 patients with 73 neoplastic polyps 1 cm or bigger underwent unenhanced and dual-phase (arterial and portal venous phases) multi-detector row computed tomography. Gallbladder polyps were diagnosed by cholecystectomy. Computed tomographic features including size (1.5 cm), surface (smooth or irregular), shape (pedunculated or sessile), accompanying wall thickening, basal indentation, perception on unenhanced images, and enhancement pattern between 2 groups were compared using univariate and multivariate analyses. On univariate analysis, age 55 years or older (P = 0.0019), size bigger than 1.5 cm (P < 0.0001), irregular surface (P = 0.0033), sessile shape (P = 0.0016), accompanying wall thickening (P = 0.0056), basal indentation (P = 0.0236), and perception on unenhanced images (P < 0.0001) were significantly more frequent in neoplastic polyps as compared with nonneoplastic polyps. On multivariate analysis, size bigger than 1.5 cm (P = 0.0260), sessile shape (P = 0.0397), and perception on unenhanced images (P < 0.0001) were statistically significant. Size bigger than 1.5 cm, sessile shape, and perception on unenhanced images are the main factors that differentiate neoplastic from nonneoplastic gallbladder polyps 1 cm or bigger.

Steady state temperature distribution in dermal regions of an irregular tapered shaped human limb with variable eccentricity.

PubMed

Agrawal, M; Pardasani, K R; Adlakha, N

2014-08-01

The investigators in the past have developed some models of temperature distribution in the human limb assuming it as a regular circular or elliptical tapered cylinder. But in reality the limb is not of regular tapered cylindrical shape. The radius and eccentricity are not same throughout the limb. In view of above a model of temperature distribution in the irregular tapered elliptical shaped human limb is proposed for a three dimensional steady state case in this paper. The limb is assumed to be composed of multiple cylindrical substructures with variable radius and eccentricity. The mathematical model incorporates the effect of blood mass flow rate, metabolic activity and thermal conductivity. The outer surface is exposed to the environment and appropriate boundary conditions have been framed. The finite element method has been employed to obtain the solution. The temperature profiles have been computed in the dermal layers of a human limb and used to study the effect of shape, microstructure and biophysical parameters on temperature distribution in human limbs. The proposed model is one of the most realistic model as compared to conventional models as this can be effectively employed to every regular and nonregular structures of the body with variable radius and eccentricity to study the thermal behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Neural adaptation to thin and fat bodies in the fusiform body area and middle occipital gyrus: an fMRI adaptation study.

PubMed

Hummel, Dennis; Rudolf, Anne K; Brandi, Marie-Luise; Untch, Karl-Heinz; Grabhorn, Ralph; Hampel, Harald; Mohr, Harald M

2013-12-01

Visual perception can be strongly biased due to exposure to specific stimuli in the environment, often causing neural adaptation and visual aftereffects. In this study, we investigated whether adaptation to certain body shapes biases the perception of the own body shape. Furthermore, we aimed to evoke neural adaptation to certain body shapes. Participants completed a behavioral experiment (n = 14) to rate manipulated pictures of their own bodies after adaptation to demonstratively thin or fat pictures of their own bodies. The same stimuli were used in a second experiment (n = 16) using functional magnetic resonance imaging (fMRI) adaptation. In the behavioral experiment, after adapting to a thin picture of the own body participants also judged a thinner than actual body picture to be the most realistic and vice versa, resembling a typical aftereffect. The fusiform body area (FBA) and the right middle occipital gyrus (rMOG) show neural adaptation to specific body shapes while the extrastriate body area (EBA) bilaterally does not. The rMOG cluster is highly selective for bodies and perhaps body parts. The findings of the behavioral experiment support the existence of a perceptual body shape aftereffect, resulting from a specific adaptation to thin and fat pictures of one's own body. The fMRI results imply that body shape adaptation occurs in the FBA and the rMOG. The role of the EBA in body shape processing remains unclear. The results are also discussed in the light of clinical body image disturbances. Copyright © 2012 Wiley Periodicals, Inc.

Do Mouthwashes Really Kill Bacteria?

ERIC Educational Resources Information Center

Corner, Thomas R.

1984-01-01

Errors in determining the effectiveness of mouthwashes, disinfectants, and other household products as antibacterial agents may result from using broth cultures and/or irregularly shaped bits of filter paper. Presents procedures for a better technique and, for advanced students, two additional procedures for introducing quantitative analysis into…

Dark and Bright Material in a Crater Wall

NASA Image and Video Library

2012-03-28

This image from NASA Dawn spacecraft shows part of a large crater that has an irregularly shaped, fresh rim and is distinctive because it has many outcrops of dark and bright material originating from its rim and from the interior slope of the crater.

A sampling strategy to estimate the area and perimeter of irregularly shaped planar regions

Treesearch

Timothy G. Gregoire; Harry T. Valentine

1995-01-01

The length of a randomly oriented ray emanating from an interior point of a planar region can be used to unbiasedly estimate the region's area and perimeter. Estimators and corresponding variance estimators under various selection strategies are presented.

Portable Horizontal-Drilling And Positioning Device

NASA Technical Reports Server (NTRS)

Smigocki, Edmund; Johnson, Clarence

1988-01-01

Portable horizontal-drilling and positioning device, constructed mainly of off-the-shelf components, accurately drills horizontal small holes in irregularly shaped objects. Holes precisely placed and drilled in objects that cannot be moved to shop area. New device provides three axes of movement while maintaining horizontal drilling.

Image-guided spatial localization of heterogeneous compartments for magnetic resonance

PubMed Central

An, Li; Shen, Jun

2015-01-01

Purpose: Image-guided localization SPectral Localization Achieved by Sensitivity Heterogeneity (SPLASH) allows rapid measurement of signals from irregularly shaped anatomical compartments without using phase encoding gradients. Here, the authors propose a novel method to address the issue of heterogeneous signal distribution within the localized compartments. Methods: Each compartment was subdivided into multiple subcompartments and their spectra were solved by Tikhonov regularization to enforce smoothness within each compartment. The spectrum of a given compartment was generated by combining the spectra of the components of that compartment. The proposed method was first tested using Monte Carlo simulations and then applied to reconstructing in vivo spectra from irregularly shaped ischemic stroke and normal tissue compartments. Results: Monte Carlo simulations demonstrate that the proposed regularized SPLASH method significantly reduces localization and metabolite quantification errors. In vivo results show that the intracompartment regularization results in ∼40% reduction of error in metabolite quantification. Conclusions: The proposed method significantly reduces localization errors and metabolite quantification errors caused by intracompartment heterogeneous signal distribution. PMID:26328977

Radiofrequency-sputtered coatings for lubrication system components and other complex surfaces

NASA Technical Reports Server (NTRS)

Spalvins, T.

1972-01-01

Irregularly shaped surfaces, such as lubrication system components (ball bearings, seals, gears, etc.), can be coated on all surfaces, including irregular shapes, when radiofrequency sputtering is used. When the specimen is properly located with respect to the sputtering target, the sputtered material covers the entire surface of the object irrespective of its geometrical configuration. An adherent, dense film is formed. The film thickness varies from 20 to 50 percent on, for example, a hearing cage or race depending on its geometry. When sputtered solid film lubricants such as molybdenum disulfide are used, a film thickness only of the order of 10 to the minus 7th power m (thousands of angstroms) is required at the contacting areas. It is only essential to determine the required film thickness at the critical areas in need of lubrication. The sections outside the areas to be lubricated fall within the thickness deviation range of 20 to 50 percent, which still constitutes a negligible change respect to tolerance requirements.

Optimal design approach for heating irregular-shaped objects in three-dimensional radiant furnaces using a hybrid genetic algorithm-artificial neural network method

NASA Astrophysics Data System (ADS)

Darvishvand, Leila; Kamkari, Babak; Kowsary, Farshad

2018-03-01

In this article, a new hybrid method based on the combination of the genetic algorithm (GA) and artificial neural network (ANN) is developed to optimize the design of three-dimensional (3-D) radiant furnaces. A 3-D irregular shape design body (DB) heated inside a 3-D radiant furnace is considered as a case study. The uniform thermal conditions on the DB surfaces are obtained by minimizing an objective function. An ANN is developed to predict the objective function value which is trained through the data produced by applying the Monte Carlo method. The trained ANN is used in conjunction with the GA to find the optimal design variables. The results show that the computational time using the GA-ANN approach is significantly less than that of the conventional method. It is concluded that the integration of the ANN with GA is an efficient technique for optimization of the radiant furnaces.

Resonant frequencies of irregularly shaped microstrip antennas using method of moments

NASA Technical Reports Server (NTRS)

Deshpande, Manohar D.; Shively, David G.; Cockrell, C. R.

1993-01-01

This paper describes an application of the method of moments to determine resonant frequencies of irregularly shaped microstrip patches embedded in a grounded dielectric slab. For analysis, the microstrip patch is assumed to be excited by a linearly polarized plane wave that is normal to the patch. The surface-current density that is induced on the patch because of the incident field is expressed in terms of subdomain functions by dividing the patch into identical rectangular subdomains. The amplitudes of the subdomain functions, as a function of frequency, are determined using the electric-field integral equation (EFIE) approach in conjunction with the method of moments. The resonant frequencies of the patch are then obtained by selecting the frequency at which the amplitude of the surface-current density is real. The resonant frequencies of the equilateral triangular and other nonrectangular patches are computed using the present technique, and these frequencies are compared with measurements and other independent calculations.

Nonlinear radiated MHD flow of nanoliquids due to a rotating disk with irregular heat source and heat flux condition

NASA Astrophysics Data System (ADS)

Mahanthesh, B.; Gireesha, B. J.; Shehzad, S. A.; Rauf, A.; Kumar, P. B. Sampath

2018-05-01

This research is made to visualize the nonlinear radiated flow of hydromagnetic nano-fluid induced due to rotation of the disk. The considered nano-fluid is a mixture of water and Ti6Al4V or AA7072 nano-particles. The various shapes of nanoparticles like lamina, column, sphere, tetrahedron and hexahedron are chosen in the analysis. The irregular heat source and nonlinear radiative terms are accounted in the law of energy. We used the heat flux condition instead of constant surface temperature condition. Heat flux condition is more relativistic and according to physical nature of the problem. The problem is made dimensionless with the help of suitable similarity constraints. The Runge-Kutta-Fehlberg scheme is adopted to find the numerical solutions of governing nonlinear ordinary differential systems. The solutions are plotted by considering the various values of emerging physical constraints. The effects of various shapes of nanoparticles are drawn and discussed.

Nanoscale Mechanical Properties of Nanoindented Ni48.8Mn27.2Ga24 Ferromagnetic Shape Memory Thin Film

PubMed Central

Fu, Xiaofei; Li, Xianli; Lv, Jingwei; Wang, Famei; Wang, Liying

2017-01-01

The structure and nanoscale mechanical properties of Ni48.8Mn27.2Ga24 thin film fabricated by DC magnetron sputtering are investigated systematically. The thin film has the austenite state at room temperature with the L21 Hesuler structure. During nanoindentation, stress-induced martensitic transformation occurs on the nanoscale for the film annealed at 823 K for 1 hour and the shape recovery ratio is up to 85.3%. The associated mechanism is discussed. PMID:29109812

The Characterization of Thin Film Nickel Titanium Shape Memory Alloys

NASA Astrophysics Data System (ADS)

Harris Odum, Nicole Latrice

Shape memory alloys (SMA) are able to recover their original shape through the appropriate heat or stress exposure after enduring mechanical deformation at a low temperature. Numerous alloy systems have been discovered which produce this unique feature like TiNb, AgCd, NiAl, NiTi, and CuZnAl. Since their discovery, bulk scale SMAs have undergone extensive material property investigations and are employed in real world applications. However, its thin film counterparts have been modestly investigated and applied. Researchers have introduced numerous theoretical microelectromechanical system (MEMS) devices; yet, the research community's overall unfamiliarity with the thin film properties has delayed growth in this area. In addition, it has been difficult to outline efficient thin film processing techniques. In this dissertation, NiTi thin film processing and characterization techniques will be outlined and discussed. NiTi thin films---1 mum thick---were produced using sputter deposition techniques. Substrate bound thin films were deposited to analysis the surface using Scanning Electron Microscopy; the film composition was obtained using Energy Dispersive Spectroscopy; the phases were identified using X-ray diffraction; and the transformation temperatures acquired using resistivity testing. Microfabrication processing and sputter deposition were employed to develop tensile membranes for membrane deflection experimentation to gain insight on the mechanical properties of the thin films. The incorporation of these findings will aid in the movement of SMA microactuation devices from theory to fruition and greatly benefit industries such as medicinal and aeronautical.

A simple homogeneous model for regular and irregular metallic wire media samples

NASA Astrophysics Data System (ADS)

Kosulnikov, S. Y.; Mirmoosa, M. S.; Simovski, C. R.

2018-02-01

To simplify the solution of electromagnetic problems with wire media samples, it is reasonable to treat them as the samples of a homogeneous material without spatial dispersion. The account of spatial dispersion implies additional boundary conditions and makes the solution of boundary problems difficult especially if the sample is not an infinitely extended layer. Moreover, for a novel type of wire media - arrays of randomly tilted wires - a spatially dispersive model has not been developed. Here, we introduce a simplistic heuristic model of wire media samples shaped as bricks. Our model covers WM of both regularly and irregularly stretched wires.

The shape and motion of gas bubbles in a liquid flowing through a thin annulus

NASA Astrophysics Data System (ADS)

Lei, Qinghua; Xie, Zhihua; Pavlidis, Dimitrios; Salinas, Pablo; Veltin, Jeremy; Muggeridge, Ann; Pain, Christopher C.; Matar, Omar K.; Jackson, Matthew; Arland, Kristine; Gyllensten, Atle

2017-11-01

We study the shape and motion of gas bubbles in a liquid flowing through a horizontal or slightly-inclined thin annulus. Experimental data show that in the horizontal annulus, bubbles develop a unique ``tadpole'' shape with an elliptical cap and a highly-stretched tail, due to the confinement between the closely-spaced channel walls. As the annulus is inclined, the bubble tail tends to decrease in length, while the geometry of the cap remains almost invariant. To model the bubble evolution, the thin annulus is conceptualised as a ``Hele-Shaw'' cell in a curvilinear space. The three-dimensional flow within the cell is represented by a gap-averaged, two-dimensional model constrained by the same dimensionless quantities. The complex bubble dynamics are solved using a mixed control-volume finite-element method combined with interface-capturing and mesh adaptation techniques. A close match to the experimental data is achieved, both qualitatively and quantitatively, by the numerical simulations. The mechanism for the elliptical cap formation is interpreted based on an analogous irrotational flow field around a circular cylinder. The shape regimes of bubbles flowing through the thin annulus are further explored based on the simulation results. Funding from STATOIL gratefully acknowledged.

Geoboard and Balance Activities for the Gifted Child.

ERIC Educational Resources Information Center

Bondy, Kay W.

1979-01-01

The author describes mathematics activities for gifted children which make use of the geoboard and balance. The problem, solutions, and theoretical backing are provided for determining areas of squares, areas of irregular shapes, the weight of popped and unpopped popcorn, kernels, and liquid mass and density. (SBH)

An emerging disease in blueberry caused by a novel RNA virus

USDA-ARS?s Scientific Manuscript database

A new disorder was observed on southern highbush blueberry (Vaccinium corymbosum interspecific hybrids) in several southeastern states. Symptoms included irregularly shaped circular spots or blotches with green centers on the top and bottom of leaves. The disease was reported initially in the state ...

Blueberry necrotic ring blotch, a new blueberry disease caused by a virus

USDA-ARS?s Scientific Manuscript database

Novel symptoms have been observed on southern highbush blueberries (Vaccinium corymbosum interspecific hybrids) in several southeastern states. Affected plants show irregularly shaped circular spots or blotches with green centers on the top and bottoms of leaves. Diagnostic tests failed to isolate a...

Near-equilibrium dumb-bell-shaped figures for cohesionless small bodies

NASA Astrophysics Data System (ADS)

Descamps, Pascal

2016-02-01

In a previous paper (Descamps, P. [2015]. Icarus 245, 64-79), we developed a specific method aimed to retrieve the main physical characteristics (shape, density, surface scattering properties) of highly elongated bodies from their rotational lightcurves through the use of dumb-bell-shaped equilibrium figures. The present work is a test of this method. For that purpose we introduce near-equilibrium dumb-bell-shaped figures which are base dumb-bell equilibrium shapes modulated by lognormal statistics. Such synthetic irregular models are used to generate lightcurves from which our method is successfully applied. Shape statistical parameters of such near-equilibrium dumb-bell-shaped objects are in good agreement with those calculated for example for the Asteroid (216) Kleopatra from its dog-bone radar model. It may suggest that such bilobed and elongated asteroids can be approached by equilibrium figures perturbed be the interplay with a substantial internal friction modeled by a Gaussian random sphere.

Photoelectrochemical etching of epitaxial InGaN thin films: Self-limited kinetics and nanostructuring

DOE PAGES

Xiao, Xiaoyin; Fischer, Arthur J.; Coltrin, Michael E.; ...

2014-10-22

We report here the characteristics of photoelectrochemical (PEC) etching of epitaxial InGaN semiconductor thin films using narrowband lasers with linewidth less than ~1 nm. In the initial stages of PEC etching, when the thin film is flat, characteristic voltammogram shapes are observed. At low photo-excitation rates, voltammograms are S-shaped, indicating the onset of a voltage-independent rate-limiting process associated with electron-hole-pair creation and/or annihilation. At high photo-excitation rates, voltammograms are superlinear in shape, indicating, for the voltage ranges studied here, a voltage-dependent rate-limiting process associated with surface electrochemical oxidation. As PEC etching proceeds, the thin film becomes rough at the nanoscale,more » and ultimately evolves into an ensemble of nanoparticles. As a result, this change in InGaN film volume and morphology leads to a characteristic dependence of PEC etch rate on time: an incubation time, followed by a rise, then a peak, then a slow decay.« less

Passive Nosetip Technology (PANT) Program. Volume 14. An Experimental Study to Evaluate the Irregular Nosetip Shape Regime - Data Report

DTIC Science & Technology

1974-04-01

described in Section 2.3. 2.1 MODEL FABRICATION AND MOUNTING Camphor and camphor with distributed glass particles were the materials for the low...temperature ablator shape-change models tested in Series I. The models were fabricated by molding the camphor at room temperature and high pressure (20,000 psi...distributed glass particles were produced by thoroughly mixing glass beads, having diameters of 7.5 t 1.5 mils, with the camphor gran- ules prior to

Programmable, reversible and repeatable wrinkling of shape memory polymer thin films on elastomeric substrates for smart adhesion.

PubMed

Wang, Yu; Xiao, Jianliang

2017-08-09

Programmable, reversible and repeatable wrinkling of shape memory polymer (SMP) thin films on elastomeric polydimethylsiloxane (PDMS) substrates is realized, by utilizing the heat responsive shape memory effect of SMPs. The dependencies of wrinkle wavelength and amplitude on program strain and SMP film thickness are shown to agree with the established nonlinear buckling theory. The wrinkling is reversible, as the wrinkled SMP thin film can be recovered to the flat state by heating up the bilayer system. The programming cycle between wrinkle and flat is repeatable, and different program strains can be used in different programming cycles to induce different surface morphologies. Enabled by the programmable, reversible and repeatable SMP film wrinkling on PDMS, smart, programmable surface adhesion with large tuning range is demonstrated.

Percolation in three-dimensional fracture networks for arbitrary size and shape distributions

NASA Astrophysics Data System (ADS)

Thovert, J.-F.; Mourzenko, V. V.; Adler, P. M.

2017-04-01

The percolation threshold of fracture networks is investigated by extensive direct numerical simulations. The fractures are randomly located and oriented in three-dimensional space. A very wide range of regular, irregular, and random fracture shapes is considered, in monodisperse or polydisperse networks containing fractures with different shapes and/or sizes. The results are rationalized in terms of a dimensionless density. A simple model involving a new shape factor is proposed, which accounts very efficiently for the influence of the fracture shape. It applies with very good accuracy in monodisperse or moderately polydisperse networks, and provides a good first estimation in other situations. A polydispersity index is shown to control the need for a correction, and the corrective term is modelled for the investigated size distributions.

Striation patterns in serrated blade stabs to cartilage.

PubMed

Pounder, Derrick J; Reeder, Francesca D

2011-05-20

Stab wounds were made in porcine cartilage with 13 serrated knives, amongst which 4 were drop-point and 9 straight-spine; 9 coarsely serrated, 3 finely serrated and 1 with mixed pattern serrations. The walls of the stab tracks were cast with dental impression material, and the casts photographed together with the knife blades for comparison. All 13 serrated blades produced an "irregularly regular" pattern of striations on cartilage in all stabbings. Unusual and distinctive blade serration patterns produced equally distinctive wound striation patterns. A reference collection of striation patterns and corresponding blades might prove useful for striation pattern analysis. Drop-point blades produced similar striations to straight-spine blades except that the striations were not parallel but rather fan-shaped, converging towards the wound exit. The fan-shaped striation pattern characteristic of drop-point blades is explained by the initial lateral movement of the blade through the cartilage imposed by the presence of the drop point shape. It appears that the greater the overall angle of the drop point, the shorter the blade length over which the drop point occurs, and the closer the first serration is to the knife tip, the more obvious is the fan-shaped pattern. We anticipate that micro-irregularities producing individualising characteristics in non-serrated drop point blades, provided they were located at the tip opposite the drop point, should also show a fan-shaped pattern indicative of a drop point blade. The examination of the walls of stab wounds to cartilage represents an under-utilised source of forensic information to assist in knife identification. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

More irregular eye shape in low myopia than in emmetropia.

PubMed

Tabernero, Juan; Schaeffel, Frank

2009-09-01

To improve the description of the peripheral eye shape in myopia and emmetropia by using a new method for continuous measurement of the peripheral refractive state. A scanning photorefractor was designed to record refractive errors in the vertical pupil meridian across the horizontal visual field (up to +/-45 degrees ). The setup consists of a hot mirror that continuously projects the infrared light from a photoretinoscope under different angles of eccentricity into the eye. The movement of the mirror is controlled by using two stepping motors. Refraction in a group of 17 emmetropic subjects and 11 myopic subjects (mean, -4.3 D; SD, 1.7) was measured without spectacle correction. For the analysis of eye shape, the refractive error versus the eccentricity angles was fitted with different polynomials (from second to tenth order). The new setup presents some important advantages over previous techniques: The subject does not have to change gaze during the measurements, and a continuous profile is obtained rather than discrete points. There was a significant difference in the fitting errors between the subjects with myopia and those with emmetropia. Tenth-order polynomials were required in myopic subjects to achieve a quality of fit similar to that in emmetropic subjects fitted with only sixth-order polynomials. Apparently, the peripheral shape of the myopic eye is more "bumpy." A new setup is presented for obtaining continuous peripheral refraction profiles. It was found that the peripheral retinal shape is more irregular even in only moderately myopic eyes, perhaps because the sclera lost some rigidity even at the early stage of myopia.

Evaluation of chondromalacia of the patellofemoral compartment with axial magnetic resonance imaging.

PubMed

Brown, T R; Quinn, S F

1993-01-01

Axial magnetic resonance (MR) imaging of the patellofemoral compartment was performed in 75 patients with arthroscopic correlation. Proton density and T2(2500/20/80) weighted images were obtained in all patients. Chondromalacia in stages I and II could not be reliably identified with MR imaging. For the evaluation of stage III and IV chondromalacia, the accuracy of MR was 89%. Focal or diffuse areas of increased or decreased signal alterations of the hyaline cartilage without a contour deformity or cartilaginous thinning do not correlate reliably with arthroscopic staging of chondromalacia. A normal signal intensity is no assurance that softening of the cartilage is not present. The most reliable indicators of chondromalacia are focal contour irregularities of the hyaline cartilage and/or thinning of the hyaline cartilage associated with high signal intensity changes within frank defects or contour irregularities with T2-weighted images. The poor MR-arthroscopic correlation in earlier stages of chondromalacia may be due in part to the subjective basis of the arthroscopic diagnosis. In conclusion, stage I and II chondromalacia of the patellofemoral compartment cannot be reliably evaluated with MR imaging. Stage III and IV chondromalacia is reliably evaluated with MR using the combination of proton density and T2-weighted images.

Rationally Controlled Synthesis of CdSexTe1-x Alloy Nanocrystals and Their Application in Efficient Graded Bandgap Solar Cells.

PubMed

Wen, Shiya; Li, Miaozi; Yang, Junyu; Mei, Xianglin; Wu, Bin; Liu, Xiaolin; Heng, Jingxuan; Qin, Donghuan; Hou, Lintao; Xu, Wei; Wang, Dan

2017-11-08

CdSe x Te 1-x semiconductor nanocrystals (NCs), being rod-shaped/irregular dot-shaped in morphology, have been fabricated via a simple hot-injection method. The NCs composition is well controlled through varying molar ratios of Se to Te precursors. Through changing the composition of the CdSe x Te 1-x NCs, the spectral absorption of the NC thin film between 570-800 nm is proved to be tunable. It is shown that the bandgap of homogeneously alloyed CdSe x Te 1-x active thin film is nonlinearly correlated with the different compositions, which is perceived as optical bowing. The solar cell devices based on CdSe x Te 1-x NCs with the structure of ITO/ZnO/CdSe/CdSe x Te 1-x /MoO x /Au and the graded bandgap ITO/ZnO/CdSe( w / o )/CdSe x Te 1-x /CdTe/MoO x /Au are systematically evaluated. It was found that the performance of solar cells degrades almost linearly with the increase of alloy NC film thickness with respect to ITO/ZnO/CdSe/CdSe 0.2 Te 0.8 /MoO x /Au. From another perspective, in terms of the graded bandgap structure of ITO/ZnO/CdSe/CdSe x Te 1-x /CdTe/MoO x /Au, the performance is improved in contrast with its single-junction analogues. The graded bandgap structure is proved to be efficient when absorbing spectrum and the solar cells fabricated under the structure of ITO/ZnO/CdSe 0.8 Te 0.2 /CdSe 0.2 Te 0.8 /CdTe/MoO x /Au indicate power conversion efficiency (PCE) of 6.37%, a value among the highest for solution-processed inversely-structured CdSe x Te 1-x NC solar cells. As the NC solar cells are solution-processed under environmental conditions, they are promising for fabricating solar cells at low cost, roll by roll and in large area.

Rationally Controlled Synthesis of CdSexTe1−x Alloy Nanocrystals and Their Application in Efficient Graded Bandgap Solar Cells

PubMed Central

Wen, Shiya; Li, Miaozi; Yang, Junyu; Mei, Xianglin; Wu, Bin; Liu, Xiaolin; Heng, Jingxuan; Hou, Lintao; Xu, Wei; Wang, Dan

2017-01-01

CdSexTe1−x semiconductor nanocrystals (NCs), being rod-shaped/irregular dot-shaped in morphology, have been fabricated via a simple hot-injection method. The NCs composition is well controlled through varying molar ratios of Se to Te precursors. Through changing the composition of the CdSexTe1−x NCs, the spectral absorption of the NC thin film between 570–800 nm is proved to be tunable. It is shown that the bandgap of homogeneously alloyed CdSexTe1−x active thin film is nonlinearly correlated with the different compositions, which is perceived as optical bowing. The solar cell devices based on CdSexTe1−x NCs with the structure of ITO/ZnO/CdSe/CdSexTe1−x/MoOx/Au and the graded bandgap ITO/ZnO/CdSe(w/o)/CdSexTe1−x/CdTe/MoOx/Au are systematically evaluated. It was found that the performance of solar cells degrades almost linearly with the increase of alloy NC film thickness with respect to ITO/ZnO/CdSe/CdSe0.2Te0.8/MoOx/Au. From another perspective, in terms of the graded bandgap structure of ITO/ZnO/CdSe/CdSexTe1−x/CdTe/MoOx/Au, the performance is improved in contrast with its single-junction analogues. The graded bandgap structure is proved to be efficient when absorbing spectrum and the solar cells fabricated under the structure of ITO/ZnO/CdSe0.8Te0.2/CdSe0.2Te0.8/CdTe/MoOx/Au indicate power conversion efficiency (PCE) of 6.37%, a value among the highest for solution-processed inversely-structured CdSexTe1−x NC solar cells. As the NC solar cells are solution-processed under environmental conditions, they are promising for fabricating solar cells at low cost, roll by roll and in large area. PMID:29117132

[The relations of corneal, lenticular and total astigmatism].

PubMed

Liang, D; Guan, Z; Lin, J

1995-06-01

To determine the relations of corneal, lenticular and total astigmatism and the changes of the astigmatism with age. Out-patients with refractive errors were refracted with retinoscope after using cycloplegic drops and measured the radii of anterior corneal curvature. One hundred and ninety-four cases (382 eyes) with refractive errors were studied. Of the eyes 67.9% had regular corneal astigmatism, 68.1% irregular lenticular astigmatism and 60.7% regular total astigmatism, 88.5% of the corneal astigmatism has the same quality as the total astigmatism. The total astigmatism in 46% of the eyes included the summation of corneal and lenticular astigmatism, but in 41.3% of the eyes irregular lenticular astigmatism corrected the regular corneal astigmatism. The astigmatism of cornea, lens and total astigmatism changed from regular to irregular with the increase of age. The linear correlation analysis showed a positive correlation between the power of horizontal corneal refraction and age, and a negative corrlation between the power of vertical corneal refraction and age. The shape of cornea was the major cause of total astigmatism. The influence of lens on the total astigmatism was different. The reasons for the change of the total astigmatism from regular to irregular with the increase of age were the changes of the power of corneal refraction, particularly the increase of the power of horizontal corneal refraction and lenticular irregular astigmatism.

Deformation of the Tonga Slab: Evidence for Interaction with a Small-scale Secondary Plume in the Transition Zone

NASA Astrophysics Data System (ADS)

Billen, M. I.; Bikoba, J. Z.; Tarlow, S.

2015-12-01

Magali I. Billen and John Z. BikobaThe Tonga Slab is the most seismically active subduction zone providing a uniquely detailed picture of the internal deformation of the slab, with apparent warping and folding, from the surface through the transition zone. Here, we investigate the dynamical origin of a irregular feature in the seismicity within the transition zone located at 21-28oS, using 3D visualization and analysis of the seismicity and compression/tension (P/T) axis from the moment tensor solutions to characterize the geometry of, and the orientation of forces acting on, the slab. This irregular feature can be described as narrow region of upward deflection of the slab, with a gap in seismicity beyond (down-dip of) the deflected region, and flanked by two narrow V-shaped gaps in seismicity suggestive of tearing of the slab. The P/T axis show a dominate down-dip orientation of the P axis above the deflection point, which rotate to a nearly vertical orientation within the central region of the deflected slab. The adjacent attached regions (down-dip of the two flanking slab gaps) also have rotated and more heterogeneous P/T axis orientations. In contrast, the adjacent section of the slab to the north of 21oS has continuous seismicity throughout the transition zone, with a roughly uniform planar shape, and generally down-dip orientation of the P axis. We explore three possible hypothesis for the observed deformation including: 1) deflection due to a buoyant metastable olivine wedge, 2) a buckling feature in the slab as previously proposed by Myhill (GJI., 2013), and interaction with a small-scale, secondary plume upwelling below the slab. If the newly-observed gaps in seismicity indicate physical gaps or significant thinning of the slab, then these observations are not consistent with the buckling hypothesis. The lack of significant along-strike variation in slab age or subduction rate also suggests that a localized region of metastable olivine is unlikely. Therefore, we test the third hypothesis using a simple 3D geodynamical model of a planar dipping slab overlying a localized buoyant upwelling (radius < 150 km). We present comparisons of the observations to the model predictions for the subsequent deformation of the slab and orientations of principal stress axis within the slab.

Preference for attractiveness and thinness in a partner: influence of internalization of the thin ideal and shape/weight dissatisfaction in heterosexual women, heterosexual men, lesbians, and gay men.

PubMed

Legenbauer, Tanja; Vocks, Silja; Schäfer, Corinna; Schütt-Strömel, Sabine; Hiller, Wolfgang; Wagner, Christof; Vögele, Claus

2009-06-01

This study assesses whether characteristics of one's own body image influences preferences of attractiveness in a partner. The role of gender and sexual orientation is also considered. Heterosexual women (n=67), lesbian women (n=73), heterosexual men (n=61) and gay men (n=82) participated in an internet survey assessing attitudes towards the body and preferences of attractiveness in a partner. Men in particular were found to prefer attractive partners, regardless of sexual orientation. Weight/shape dissatisfaction was found to be a negative predictor for heterosexual men and women. For gay men, preferences were better explained by internalization and weight/shape dissatisfaction. No such associations were found in the lesbian group. Levels of weight/shape dissatisfaction and internalization of socio-cultural slenderness ideals influence expectations of thinness and attractiveness in a partner with this effect being modified by gender and sexual orientation.

Cloaking of arbitrarily shaped objects with homogeneous coatings

NASA Astrophysics Data System (ADS)

Forestiere, Carlo; Dal Negro, Luca; Miano, Giovanni

2014-05-01

We present a theory for the cloaking of arbitrarily shaped objects and demonstrate electromagnetic scattering cancellation through designed homogeneous coatings. First, in the small-particle limit, we expand the dipole moment of a coated object in terms of its resonant modes. By zeroing the numerator of the resulting rational function, we accurately predict the permittivity values of the coating layer that abates the total scattered power. Then, we extend the applicability of the method beyond the small-particle limit, deriving the radiation corrections of the scattering-cancellation permittivity within a perturbation approach. Our method permits the design of invisibility cloaks for irregularly shaped devices such as complex sensors and detectors.

Effect of Particle Morphology on the Reactivity of Explosively Dispersed Titanium Particles

NASA Astrophysics Data System (ADS)

Frost, David; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2009-06-01

The effect of particle morphology on the reaction of titanium (Ti) particles explosively dispersed during the detonation of either cylindrical or spherical charges has been investigated experimentally. The explosive charges consisted of packed beds of Ti particles saturated with nitromethane. The reaction behavior of irregularly-shaped Ti particles in three size ranges is compared with tests with spherical Ti particles. The particle reaction is strongly dependent on particle morphology, e.g., 95 μm spherical Ti particles failed to ignite (in cylinders up to 49 mm in dia), whereas similarly sized irregular Ti particles readily ignited. For irregular particles, the uniformity of ignition on the particle cloud surface was almost independent of particle size, but depended on charge diameter. As the charge diameter was reduced, ignition in the conically expanding particle cloud occurred only at isolated spots or bands. For spherical charges, although large irregular Ti particles ignited promptly and uniformly throughout the particle cloud, the smallest particles dispersed nonuniformly and ignition occurred at isolated locations. In general, particle ignition is a competition between particle heating (which is influenced by particle morphology, size, number density and the local thermodynamic history) and expansion cooling of the products.

Reflow dynamics of thin patterned viscous films

NASA Astrophysics Data System (ADS)

Leveder, T.; Landis, S.; Davoust, L.

2008-01-01

This letter presents a study of viscous smoothening dynamics of a nanopatterned thin film. Ultrathin film manufacturing processes appearing to be a key point of nanotechnology engineering and numerous studies have been recently led in order to exhibit driving parameters of this transient surface motion, focusing on time scale accuracy method. Based on nanomechanical analysis, this letter shows that controlled shape measurements provided much more detailed information about reflow mechanism. Control of reflow process of any complex surface shape, or measurement of material parameter as thin film viscosity, free surface energy, or even Hamaker constant are therefore possible.

Mathematics without... Irregular Polygons

ERIC Educational Resources Information Center

McLeay, Heather

2007-01-01

In this article, the author reflects on her session at the 2006 conference, including the learning styles and strategies she observed. In her session, they explored some of the more unusual aspects of convex polyhedra (with regular faces), including the notions of "valence" and "species". Although the session was about shape and space, there was…

Hybrid Warfare: How to Shape Special Operations Forces

DTIC Science & Technology

2016-06-10

irregular tactics, information operations, and deliberate terrorism as they waged war against Russia in the territory of Chechnya and o deep in Russian...Russia initially had to withdraw its forces from Chechnya , but later led by a former KGB operative, Vladimir Putin, were able to defeat the Chechen rebels

33 CFR 330.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... part 325). (See 33 CFR 322.2(f) and 323.2(h) for the definition of a general permit.) (c) Authorization... several different headwaters or isolated waters, the cumulative total of all filled areas should be the... individual arms of a large, irregularly-shaped wetland or lake, etc., are not separate waterbodies. (j...

33 CFR 330.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... part 325). (See 33 CFR 322.2(f) and 323.2(h) for the definition of a general permit.) (c) Authorization... several different headwaters or isolated waters, the cumulative total of all filled areas should be the... individual arms of a large, irregularly-shaped wetland or lake, etc., are not separate waterbodies. (j...

International Summer Institute in Surface Science (4th), (ISISS 1979).

DTIC Science & Technology

1980-07-09

Gold crystallites growing on KC1 substrates were found, under certain conditions during the coalescence stage, to form large, irregularly shaped, very...structure up to the interface. The next part gives results issued from structural models for the crystal-melt interface of monoatomic solids. The main

76 FR 11464 - Sunshine Act Meeting; Open Commission Meeting; Thursday, March 3, 2011

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-02

... functional equivalent of Tribal Lands and to Tribal Lands that are small or irregularly shaped; and to adjust... Nations on their lands. 2 Wireless Title: Improving Communications Services Telecommunications. for Native Nations by Promoting Greater Utilization of Spectrum Over Tribal Lands. Summary: The Commission will...

The Effect of Particles Shape and Size on Feedstock Flowibility and Chemical content of As-sintered NiTi Alloys

NASA Astrophysics Data System (ADS)

Kadir, R. A. Abdul; Razali, R.; Mohamad Nor, N. H.; Subuki, I.; Ismail, M. H.

2018-05-01

This paper presents a comparative study of two different titanium powders in fabrication of NiTi alloys by metal injection moulding (MIM) route. Two batches of powder mixture consisted of Ni-Ti and Ni-TiH2 with atomic ratio (at%) of 50-50 were prepared. TiH2 powder was used as a substitution for pure Ti powder owing to its relatively cheaper cost and has been claimed favourable in producing less impurity uptake in sintering process. The binder system used for both mixtures comprised of composite binder of palm stearin (PS) and polyethylene (PE) at weigth ratio (wt%) of 60-40. The flow behaviour of the mixtures was analysed using a capillary rheometer at different shear rates and temperatures. The results showed that owing to irregular shape of TiH2 compared to Ti powder, the viscosity of the feedstock was significantly higher, thus required greater temperature in order to improve the mouldability of the feedstock. Nevertheless, both feedstocks exhibited pseudoplastic, a shear thinning behavior with shear rate and temperature, desirable properties for injection moulding process. Samples prepared with Ni-Ti feedstock were sintered in a high vacuum furnace, while Ni-TiH2 feedstock was sintered in a tube furnace under a flowing of Argon gas. The results showed that the impurity contents (Carbon and Oxygen) for both feedstocks were almost comparable, suggesting NiTi alloy samples prepared with TiH2 powder is an attractive route for manufacturing of NiTi alloys.

Cellular organization of pre-mRNA splicing factors in several tissues. Changes in the uterus by hormone action.

PubMed

George-Téllez, R; Segura-Valdez, M L; González-Santos, L; Jiménez-García, L F

2002-05-01

In the mammalian cell nucleus, splicing factors are distributed in nuclear domains known as speckles or splicing factor compartments (SFCs). In cultured cells, these domains are dynamic and reflect transcriptional and splicing activities. We used immunofluorescence and confocal microscopy to monitor whether splicing factors in differentiated cells display similar features. Speckled patterns are observed in rat hepatocytes, beta-cells, bronchial and intestine epithelia and also in three cell types of the uterus. Moreover, the number, distribution and sizes of the speckles vary among them. In addition, we studied variations in the circular form (shape) of speckles in uterine cells that are transcriptionally modified by a hormone action. During proestrus of the estral cycle, speckles are irregular in shape while in diestrus I they are circular. Experimentally, in castrated rats luminal epithelial cells show a pattern where speckles are dramatically rounded, but they recover their irregular shape rapidly after an injection of estradiol. The same results were observed in muscle and gland epithelial cells of the uterus. We concluded that different speckled patterns are present in various cells types in differentiated tissues and that these patterns change in the uterus depending upon the presence or absence of hormones such as estradiol.

A flexible spatial scan statistic with a restricted likelihood ratio for detecting disease clusters.

PubMed

Tango, Toshiro; Takahashi, Kunihiko

2012-12-30

Spatial scan statistics are widely used tools for detection of disease clusters. Especially, the circular spatial scan statistic proposed by Kulldorff (1997) has been utilized in a wide variety of epidemiological studies and disease surveillance. However, as it cannot detect noncircular, irregularly shaped clusters, many authors have proposed different spatial scan statistics, including the elliptic version of Kulldorff's scan statistic. The flexible spatial scan statistic proposed by Tango and Takahashi (2005) has also been used for detecting irregularly shaped clusters. However, this method sets a feasible limitation of a maximum of 30 nearest neighbors for searching candidate clusters because of heavy computational load. In this paper, we show a flexible spatial scan statistic implemented with a restricted likelihood ratio proposed by Tango (2008) to (1) eliminate the limitation of 30 nearest neighbors and (2) to have surprisingly much less computational time than the original flexible spatial scan statistic. As a side effect, it is shown to be able to detect clusters with any shape reasonably well as the relative risk of the cluster becomes large via Monte Carlo simulation. We illustrate the proposed spatial scan statistic with data on mortality from cerebrovascular disease in the Tokyo Metropolitan area, Japan. Copyright © 2012 John Wiley & Sons, Ltd.

Effects of early activator treatment in patients with class II malocclusion evaluated by thin-plate spline analysis.

PubMed

Lux, C J; Rübel, J; Starke, J; Conradt, C; Stellzig, P A; Komposch, P G

2001-04-01

The aim of the present longitudinal cephalometric study was to evaluate the dentofacial shape changes induced by activator treatment between 9.5 and 11.5 years in male Class II patients. For a rigorous morphometric analysis, a thin-plate spline analysis was performed to assess and visualize dental and skeletal craniofacial changes. Twenty male patients with a skeletal Class II malrelationship and increased overjet who had been treated at the University of Heidelberg with a modified Andresen-Häupl-type activator were compared with a control group of 15 untreated male subjects of the Belfast Growth Study. The shape changes for each group were visualized on thin-plate splines with one spline comprising all 13 landmarks to show all the craniofacial shape changes, including skeletal and dento-alveolar reactions, and a second spline based on 7 landmarks to visualize only the skeletal changes. In the activator group, the grid deformation of the total spline pointed to a strong activator-induced reduction of the overjet that was caused both by a tipping of the incisors and by a moderation of sagittal discrepancies, particularly a slight advancement of the mandible. In contrast with this, in the control group, only slight localized shape changes could be detected. Both in the 7- and 13-landmark configurations, the shape changes between the groups differed significantly at P < .001. In the present study, the morphometric approach of thin-plate spline analysis turned out to be a useful morphometric supplement to conventional cephalometrics because the complex patterns of shape change could be suggestively visualized.

Contact resistance reduction of ZnO thin film transistors (TFTs) with saw-shaped electrode.

PubMed

Park, Woojin; Shaikh, Sohail F; Min, Jung-Wook; Lee, Sang Kyung; Lee, Byoung Hun; Hussain, Muhammad M

2018-08-10

We report on a saw-shaped electrode architecture ZnO thin film transistor (TFT), which effectively increases the channel width. The contact line of the saw-shaped electrode is almost twice as long at the contact metal/ZnO channel junction. We experimentally observed an enhancement in the output drive current by 50% and a reduction in the contact resistance by over 50%, when compared to a typically shaped electrode ZnO TFT consuming the same chip area. This performance enhancement is attributed to the extension of the channel width. This technique can contribute to device performance enhancement, and in particular reduce the contact resistance, which is a serious challenge.

Evaporation From Soil Containers With Irregular Shapes

NASA Astrophysics Data System (ADS)

Assouline, Shmuel; Narkis, Kfir

2017-11-01

Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

Inorganic-organic shape memory polymers and foams for bone defect repairs

NASA Astrophysics Data System (ADS)

Zhang, Dawei

The ultimate goal of this research was to develop a "self-fitting" shape memory polymer (SMP) scaffold for the repair of craniomaxillofacial (CMF) bone defects. CMF defects may be caused by trauma, tumor removal or congenital abnormalities and represent a major class of bone defects. Their repair with autografts is limited by availability, donor site morbidity and complex surgical procedures. In addition, shaping and positioning of these rigid grafts into irregular defects is difficult. Herein, we have developed SMP scaffolds which soften at T > ˜56 °C, allowing them to conformally fit into a bone defect. Upon cooling to body temperature, the scaffold becomes rigid and mechanically locks in place. This research was comprised of four major studies. In the first study, photocrosslinkable acrylated (AcO) SMP macromers containing a poly(epsilon-caprolactone) (PCL) segment and polydimethylsiloxane (PDMS) segments were synthesized with the general formula: AcO-PCL40-block-PDMS m-block-PCL40-OAc. By varying the PDMS segment length (m), solid SMPs with highly tunable mechanical properties and excellent shape memory abilities were prepared. In the second study, porous SMP scaffolds were fabricated based on AcO-PCL 40-block-PDMS37-block-PCL 40-OAc via a revised solvent casting particulate leaching (SCPL) method. By tailoring scaffold parameters including salt fusion, macromer concentration and salt size, scaffold properties (e.g. pore features, compressive modulus and shape memory behavior) were tuned. In the third study, porous SMP scaffolds were produced from macromers with variable PDMS segment lengths (m = 0 -- 130) via an optimized SCPL method. The impact on pore features, thermal, mechanical, and shape memory properties as well as degradation rates were investigated. In the final study, a bioactive polydopamine coating was applied onto pore surfaces of the SMP scaffold prepared from PCL diacrylate. The thin coating did not affect intrinsic bulk properties of the scaffold. However, the coating significantly increased its bioactivity, giving rise to the formation of "bone-bonding" hydroxyapatite (HAp) when exposed to simulated body fluid (SBF). It was also shown that the coating largely enhanced the scaffold's capacities to support osteoblasts adhesion, proliferation and osteogenesis. Thus, the polydopamine coating should enhance the performance of the "self-fitting" SMP scaffolds for the repair of bone defects.

Dewetting of polymer thin films on modified curved surfaces: preparation of polymer nanoparticles with asymmetric shapes by anodic aluminum oxide templates.

PubMed

Liu, Chih-Ting; Tsai, Chia-Chan; Chu, Chien-Wei; Chi, Mu-Huan; Chung, Pei-Yun; Chen, Jiun-Tai

2018-04-18

We study the dewetting behaviors of poly(methyl methacrylate) (PMMA) thin films coated in the cylindrical nanopores of anodic aluminum oxide (AAO) templates by thermal annealing. Self-assembled monolayers (SAMs) of n-octadecyltrichlorosilane (ODTS) are introduced to modify the pore surfaces of the AAO templates to induce the dewetting process. By using scanning electron microscopy (SEM), the dewetting-induced morphology transformation from the PMMA thin films to PMMA nanoparticles with asymmetric shapes can be observed. The sizes of the PMMA nanoparticles can be controlled by the original PMMA solution concentrations. The dewetting phenomena on the modified nanopores are explained by taking into account the excess intermolecular interaction free energy (ΔG). This work opens a new possibility for creating polymer nanoparticles with asymmetric shapes in confined geometries.

Comparing the role of shape and texture on staging hepatic fibrosis from medical imaging

NASA Astrophysics Data System (ADS)

Zhang, Xuejun; Louie, Ryan; Liu, Brent J.; Gao, Xin; Tan, Xiaomin; Qu, Xianghe; Long, Liling

2016-03-01

The purpose of this study is to investigate the role of shape and texture in the classification of hepatic fibrosis by selecting the optimal parameters for a better Computer-aided diagnosis (CAD) system. 10 surface shape features are extracted from a standardized profile of liver; while15 texture features calculated from gray level co-occurrence matrix (GLCM) are extracted within an ROI in liver. Each combination of these input subsets is checked by using support vector machine (SVM) with leave-one-case-out method to differentiate fibrosis into two groups: normal or abnormal. The accurate rate value of all 10/15 types number of features is 66.83% by texture, while 85.74% by shape features, respectively. The irregularity of liver shape can demonstrate fibrotic grade efficiently and texture feature of CT image is not recommended to use with shape feature for interpretation of cirrhosis.

Rod-shaped cavitation bubble structure in ultrasonic field.

PubMed

Bai, Lixin; Wu, Pengfei; Liu, Huiyu; Yan, Jiuchun; Su, Chang; Li, Chao

2018-06-01

Rod-shaped cavitation bubble structure in thin liquid layers in ultrasonic field is investigated experimentally. It is found that cavitation structure successively experiences several stages with the change of the thickness of the thin liquid layer. Rod-shaped structure is a stable structure of the boundary between the cavitation cloud region and the non-cavitation liquid region, which can be formed in two different ways. Cavitation bubbles in a thin liquid layer have a distribution in the thickness direction. The rod-shaped structures tend to crosslink with each other to form stable Y-branch structures. The angle of the Y-branch structure is Gauss distribution with mathematical expectation μ = 119.93. A special rod-shaped cavitation structure with source is also investigated in detail. Due to the pressure gradient in the normal direction, the primary Bjerknes force causes the bubbles in the rod-shaped structure on both sides to converge to the axis. The secondary Bjerknes forces between the bubbles also make the cluster converge, so the large bubbles which are attached to the radiating surface tend to align themselves along the central line. According to the formula deduced in this paper, the variation of curvature of curved rod-shaped structure is qualitatively analyzed. The Y-branch structure of cavitation cloud and Plateau boundary of soap bubbles are compared. Copyright © 2018 Elsevier B.V. All rights reserved.

The fluid dynamics of the chocolate fountain

NASA Astrophysics Data System (ADS)

Townsend, Adam K.; Wilson, Helen J.

2016-01-01

We consider the fluid dynamics of the chocolate fountain. Molten chocolate is a mildly shear-thinning non-Newtonian fluid. Dividing the flow into three main domains—the pumped flow up the centre, the film flow over each dome, and the freely falling curtain flow between the domes—we generate a wide-ranging study of Newtonian and non-Newtonian fluid mechanics. The central pumped flow is a benchmark to elucidate the effects of shear-thinning. The dome flow can be modelled as a thin-film flow with the leading-order effects being a simple balance of gravity and viscosity. Finally, the curtain flow is analytically intractable but is related to the existing theory of water bells (both inviscid and viscous). In pipe flow, Newtonian fluids exhibit a parabolic velocity profile; shear-thinning makes the profile more blunted. In thin-film flow over the dome, gravitational and viscous effects balance and the dome shape is not important beyond the local slope. We find that the chocolate thins and slows down as it travels down the dome. Finally, in the curtain flow, we predict the shape of the falling sheet for an inviscid fluid, and compare this with the literature to predict the shape for a viscous fluid, having shown that viscous forces are too great to ignore. We also find that the primary effect driving the shape of the curtain (which falls inwards towards the axis of the fountain) is surface tension. We find that the three domains provide excellent introductions to non-Newtonian mechanics, the important mathematical technique of scaling, and how to manipulate existing data to make our own predictions. We also find that the topic generates interest among the public in our engagement work.

Arsenate adsorption on three types of granular schwertmannite.

PubMed

Dou, Xiaomin; Mohan, Dinesh; Pittman, Charles U

2013-06-01

Schwertmannite was synthesized on a 2 m(3)-scale and fabricated to irregular, cylindrical and spherical shape granules using drum granulation, extrusion and spray coating, respectively. The granules were systematically evaluated for As(V) removal from drinking water in terms of both performance and safety. The irregular and cylindrical shape granules (IS and CS) had larger schwertmannite loadings, higher porosity, more abundant pore structure and larger micropore volumes than those with a spherical shape (SS). As(V) adsorption kinetics on IS, CS and SS schwertmannite granules followed a pseudo-second order rate equation and two-stages of intraparticle diffusion. The rate parameters were in an order of IS > CS > SS granules. The faster uptake kinetics of the IS granules was due to their largest pore volume and interparticle porosity. Furthermore, adsorption capacities of 34, 21 and 5 mg/g, for IS, CS and SS granular schwertmannite samples were achieved at an initial As(V) concentration of 20 mg/L and adsorbent dose of 0.5 g/L. IS and CS samples performed much better over a wide pH range versus SS samples. Except for humic acid, PO4(3-) and SiO4(4-) did not inhibit As(V) adsorption on IS and CS granular specimens. SS samples worked poorly even in the absence or presence of co-existing anions. Regeneration was achieved using 0.1 M NaOH. The recycled IS and CS granular specimens can be used for 4 different cycles with no or nominal loss of adsorption capacity. Column experiments were also conducted. The IS, CS and SS granular specimens treated 8100, 4200 and 120 bed volumes (BVs) of contaminated water. No heavy metals leached from the packed granular adsorbent and appeared in the column effluent. Furthermore, the toxicity characteristic leaching procedure (TCLP) showed that the spent IS and CS granules were inert and could safely be disposed of in landfills. In short, irregular-shaped granules (IS) fabricated by drum granulation is a good candidate for arsenic removal from drinking water with a high future application potential. Copyright © 2013 Elsevier Ltd. All rights reserved.

The study on spatial distribution features of radiological plume discharged from Nuclear Power Plant based on C4ISRE

NASA Astrophysics Data System (ADS)

Ma, Yunfeng; Shen, Yue; Feng, Bairun; Yang, Fan; Li, Qiangqiang; Du, Boying; Bian, Yushan; Hu, Qiongqong; Wang, Qi; Hu, Xiaomin; Yin, Hang

2018-02-01

When the nuclear emergency accident occurs, it is very important to estimate three-dimensional space feature of the radioactive plume discharged from the source term for the emergency organization, as well as for better understanding of atmospheric dispersion processes. So, taking the Hongyanhe Nuclear Power Plant for example, the study for three-dimensional space feature of the radioactive plume is accomplished by applying atmospheric transport model (coupling of WRF-HYSPLIT) driven by FNL meteorological data of NCEP (04/01/2014-04/02/2014) based on the C4ISRE (Command, Control, Communications, Computer, Intelligence, Surveillance, Reconnaissance, Environmental Impact Assessment).The results show that the whole shape of three-dimensional plume was about irregular cloth influenced by wind; In the spatial domain (height > 16000m),the distribution of radiological plume, which looked more like horseshoe-shaped, presented irregular polygons of which the total length was 2258.7km, where covered the area of 39151km2; In the airspace from 4000m to 16000m, the plume, covered the area of 116269 km2, showed a triangle and the perimeter of that was 2280.4km; The shape of the plume was more like irregular quadrilateral, its perimeter was 2941.8km and coverage area of the plume was 131534km2;The overall distribution of the wind field showed a rectangular shape; Within the area along the horizontal direction 400m from origin to east and under height (lower than 2000m),the closer the distance coordinate (0,0), the denser the plume particles; Within the area of horizontal distance(500m-1000m) and height (4000m- 16000m), the particle density were relatively sparse and the spread extent of the plume particles from west to East was relatively large and the plume particles were mainly in the suspended state without obvious dry sedimentation; Within the area of horizontal distance (800m-1100m) and height (>16000m), there were relatively gentle horizontal diffusion of plume particles with upward drift of particles In local area.

Laser shape setting of superelastic nitinol wires: Functional properties and microstructure

NASA Astrophysics Data System (ADS)

Tuissi, Ausonio; Coduri, Mauro; Biffi, Carlo Alberto

Shape setting is one of the most important steps in the production route of Nitinol Shape Memory Alloys (SMAs), as it can fix the functional properties, such as the shape memory effect and the superelasticity (SE). The conventional method for making the shape setting is performed at 400-500∘C in furnaces. In this work, a laser beam was adopted for performing straight shape setting on commercially available austenitic Nitinol thin wires. The laser beam, at different power levels, was moved along the wire length for inducing the functional performances. Calorimetric, pseudo-elastic and microstructural features of the laser annealed wires were studied through differential scanning calorimetry, tensile testing and high energy X-ray diffraction, respectively. It can be stated that the laser technology can induce SE in thin Nitinol wires: the wire performances can be modulated in function of the laser power and improved functional properties can be obtained.

Method for hot pressing irregularly shaped refractory articles

DOEpatents

Steinkamp, William E.; Ballard, Ambrose H.

1982-01-01

The present invention is directed to a method for hot pressing irregularly haped refractory articles with these articles of varying thickness being provided with high uniform density and dimensional accuracy. Two partially pressed compacts of the refractory material are placed in a die cavity between displaceable die punches having compact-contacting surfaces of the desired article configuration. A floating, rotatable block is disposed between the compacts. The displacement of the die punches towards one another causes the block to rotate about an axis normal to the direction of movement of the die punches to uniformly distribute the pressure loading upon the compacts for maintaining substantially equal volume displacement of the powder material during the hot pressing operation.

A Simple Device for Lens-to-Sample Distance Adjustment in Laser-Induced Breakdown Spectroscopy (LIBS).

PubMed

Cortez, Juliana; Farias Filho, Benedito B; Fontes, Laiane M; Pasquini, Celio; Raimundo, Ivo M; Pimentel, Maria Fernanda; de Souza Lins Borba, Flávia

2017-04-01

A simple device based on two commercial laser pointers is described to assist in the analysis of samples that present uneven surfaces and/or irregular shapes using laser-induced breakdown spectroscopy (LIBS). The device allows for easy positioning of the sample surface at a reproducible distance from the focusing lens that conveys the laser pulse to generate the micro-plasma in a LIBS system, with reproducibility better than ±0.2 mm. In this way, fluctuations in the fluence (J cm -2 ) are minimized and the LIBS analytical signals can be obtained with a better precision even when samples with irregular surfaces are probed.

Postnatal airway growth in cystic fibrosis piglets.

PubMed

Adam, Ryan J; Abou Alaiwa, Mahmoud H; Bouzek, Drake C; Cook, Daniel P; Gansemer, Nicholas D; Taft, Peter J; Powers, Linda S; Stroik, Mallory R; Hoegger, Mark J; McMenimen, James D; Hoffman, Eric A; Zabner, Joseph; Welsh, Michael J; Meyerholz, David K; Stoltz, David A

2017-09-01

Mutations in the gene encoding the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) anion channel cause CF. The leading cause of death in the CF population is lung disease. Increasing evidence suggests that in utero airway development is CFTR-dependent and that developmental abnormalities may contribute to CF lung disease. However, relatively little is known about postnatal CF airway growth, largely because such studies are limited in humans. Therefore, we examined airway growth and lung volume in a porcine model of CF. We hypothesized that CF pigs would have abnormal postnatal airway growth. To test this hypothesis, we performed CT-based airway and lung volume measurements in 3-wk-old non-CF and CF pigs. We found that 3-wk-old CF pigs had tracheas of reduced caliber and irregular shape. Their bronchial lumens were reduced in size proximally but not distally, were irregularly shaped, and had reduced distensibility. Our data suggest that lack of CFTR results in aberrant postnatal airway growth and development, which could contribute to CF lung disease pathogenesis. NEW & NOTEWORTHY This CT scan-based study of airway morphometry in the cystic fibrosis (CF) postnatal period is unique, as analogous studies in humans are greatly limited for ethical and technical reasons. Findings such as reduced airway lumen area and irregular caliber suggest that airway growth and development are CF transmembrane conductance regulator-dependent and that airway growth defects may contribute to CF lung disease pathogenesis. Copyright © 2017 the American Physiological Society.

Patchwork Coating of Fragmented Ultra-Thin Films and Their Biomedical Applications in Burn Therapy and Antithrombotic Coating

PubMed Central

Okamura, Yosuke; Nagase, Yu; Takeoka, Shinji

2015-01-01

We have proposed free-standing centimeter-sized ultra-thin films (nanosheets) for biomedical applications. Such nanosheets exhibit unique properties such as transparency, flexibility, and good adhesiveness. However, they are only easily adhered to broad and flat surfaces due to their dimensions. To this end, we recently proposed an innovative nanomaterial: the nanosheets fragmented into submillimeter-size pieces. Intriguingly, such fragmented nanosheets could be adhered to uneven and irregular surfaces in addition to flat surfaces in a spread-out “patchwork” manner. We herein review the fabrication procedure and characterization of fragmented nanosheets composed of biodegradable polyesters and thermostable bio-friendly polymers, and their biomedical applications in burn therapy and antithrombotic coating using a “patchwork coating”. PMID:28793663

Patchwork Coating of Fragmented Ultra-Thin Films and Their Biomedical Applications in Burn Therapy and Antithrombotic Coating.

PubMed

Okamura, Yosuke; Nagase, Yu; Takeoka, Shinji

2015-11-11

We have proposed free-standing centimeter-sized ultra-thin films (nanosheets) for biomedical applications. Such nanosheets exhibit unique properties such as transparency, flexibility, and good adhesiveness. However, they are only easily adhered to broad and flat surfaces due to their dimensions. To this end, we recently proposed an innovative nanomaterial: the nanosheets fragmented into submillimeter-size pieces. Intriguingly, such fragmented nanosheets could be adhered to uneven and irregular surfaces in addition to flat surfaces in a spread-out "patchwork" manner. We herein review the fabrication procedure and characterization of fragmented nanosheets composed of biodegradable polyesters and thermostable bio-friendly polymers, and their biomedical applications in burn therapy and antithrombotic coating using a "patchwork coating".

Modeling and performance improvement of the constant power regulator systems in variable displacement axial piston pump.

PubMed

Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

2013-01-01

An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software.

Neural substrates of sublexical processing for spelling.

PubMed

DeMarco, Andrew T; Wilson, Stephen M; Rising, Kindle; Rapcsak, Steven Z; Beeson, Pélagie M

2017-01-01

We used fMRI to examine the neural substrates of sublexical phoneme-grapheme conversion during spelling in a group of healthy young adults. Participants performed a writing-to-dictation task involving irregular words (e.g., choir), plausible nonwords (e.g., kroid), and a control task of drawing familiar geometric shapes (e.g., squares). Written production of both irregular words and nonwords engaged a left-hemisphere perisylvian network associated with reading/spelling and phonological processing skills. Effects of lexicality, manifested by increased activation during nonword relative to irregular word spelling, were noted in anterior perisylvian regions (posterior inferior frontal gyrus/operculum/precentral gyrus/insula), and in left ventral occipito-temporal cortex. In addition to enhanced neural responses within domain-specific components of the language network, the increased cognitive demands associated with spelling nonwords engaged domain-general frontoparietal cortical networks involved in selective attention and executive control. These results elucidate the neural substrates of sublexical processing during written language production and complement lesion-deficit correlation studies of phonological agraphia. Copyright © 2016 Elsevier Inc. All rights reserved.

Neural Substrates of Sublexical Processing for Spelling

PubMed Central

Wilson, Stephen M.; Rising, Kindle; Rapcsak, Steven Z.; Beeson, Pélagie M.

2016-01-01

We used fMRI to examine the neural substrates of sublexical phoneme-grapheme conversion during spelling in a group of healthy young adults. Participants performed a writing-to-dictation task involving irregular words (e.g., choir), plausible nonwords (e.g., kroid), and a control task of drawing familiar geometric shapes (e.g., squares). Written production of both irregular words and nonwords engaged a left-hemisphere perisylvian network associated with reading/spelling and phonological processing skills. Effects of lexicality, manifested by increased activation during nonword relative to irregular word spelling, were noted in anterior perisylvian regions (posterior inferior frontal gyrus/operculum/precentral gyrus/insula), and in left ventral occipito-temporal cortex. In addition to enhanced neural responses within domain-specific components of the language network, the increased cognitive demands associated with spelling nonwords engaged domain-general frontoparietal cortical networks involved in selective attention and executive control. These results elucidate the neural substrates of sublexical processing during written language production and complement lesion-deficit correlation studies of phonological agraphia. PMID:27838547

Atmospheric deposition process for enhanced hybrid organic-inorganic multilayer barrier thin films for surface protection

NASA Astrophysics Data System (ADS)

Rehman, Mohammad Mutee ur; Kim, Kwang Tae; Na, Kyoung Hoan; Choi, Kyung Hyun

2017-11-01

In this study, organic polymer poly-vinyl acetate (PVA) and inorganic aluminum oxide (Al2O3) have been used together to fabricate a hybrid barrier thin film for the protection of PET substrate. The organic thin films of PVA were developed through roll to roll electrohydrodynamic atomization (R2R-EHDA) whereas the inorganic thin films of Al2O3 were grown by roll to roll spatial atmospheric atomic layer deposition (R2R-SAALD) for mass production. The use of these two technologies together to develop a multilayer hybrid organic-inorganic barrier thin films under atmospheric conditions is reported for the first time. These multilayer hybrid barrier thin films are fabricated on flexible PET substrate. Each layer of Al2O3 and PVA in barrier thin film exhibited excellent morphological, chemical and optical properties. Extremely uniform and atomically thin films of Al2O3 with average arithmetic roughness (Ra) of 1.64 nm and 1.94 nm respectively concealed the non-uniformity and irregularities in PVA thin films with Ra of 2.9 nm and 3.6 nm respectively. The optical transmittance of each layer was ∼ 80-90% while the water vapor transmission rate (WVTR) of hybrid barrier was in the range of ∼ 2.3 × 10-2 g m-2 day-1 with a total film thickness of ∼ 200 nm. Development of such hybrid barrier thin films with mass production and low cost will allow various flexible electronic devices to operate in atmospheric conditions without degradation of their properties.

Recent Greenland Thinning from Operation IceBridge ATM and LVIS Data

NASA Astrophysics Data System (ADS)

Sutterley, T. C.; Velicogna, I.

2015-12-01

We investigate regional thinning rates in Greenland using two Operation IceBridge lidar instruments, the Airborne Topographic Mapper (ATM) and the Land, Vegetation and Ice Sensor (LVIS). IceBridge and Pre-IceBridge ATM data are available from 1993 to present and IceBridge and Pre-Icebridge LVIS data are available from 2007 to present. We compare different techniques for combining the two datasets: overlapping footprints, triangulated irregular network meshing and radial basis functions. We validate the combination for periods with near term overlap of the two instruments. By combining the two lidar datasets, we are able to investigate intra-annual, annual, interannual surface elevation change. We investigate both the high melt season of 2012 and the low melt season of 2013. In addition, the major 2015 IceBridge Arctic campaign provides new crucial data for determining seasonal ice sheet thinning rates. We compare our LVIS/ATM results with surface mass balance outputs from two regional climate models: the Regional Atmospheric Climate Model (RACMO) and the Modèle Atmosphérique Régional (MAR). We also investigate the thinning rates of major outlet glaciers.

Scanning electron microscopy of the trabecular meshwork: understanding the pathogenesis of primary angle closure glaucoma.

PubMed

Sihota, Ramanjit; Goyal, Amita; Kaur, Jasbir; Gupta, Viney; Nag, Tapas C

2012-01-01

To study ultrastructural changes of the trabecular meshwork in acute and chronic primary angle closure glaucoma (PACG) and primary open angle glaucoma (POAG) eyes by scanning electron microscopy. Twenty-one trabecular meshwork surgical specimens from consecutive glaucomatous eyes after a trabeculectomy and five postmortem corneoscleral specimens were fixed immediately in Karnovsky solution. The tissues were washed in 0.1 M phosphate buffer saline, post-fixed in 1% osmium tetraoxide, dehydrated in acetone series (30-100%), dried and mounted. Normal trabecular tissue showed well-defined, thin, cylindrical uveal trabecular beams with many large spaces, overlying flatter corneoscleral beams and numerous smaller spaces. In acute PACG eyes, the trabecular meshwork showed grossly swollen, irregular trabecular endothelial cells with intercellular and occasional basal separation with few spaces. Numerous activated macrophages, leucocytes and amorphous debris were present. Chronic PACG eyes had a few, thickened posterior uveal trabecular beams visible. A homogenous deposit covered the anterior uveal trabeculae and spaces. Converging, fan-shaped trabecular beam configuration corresponded to gonioscopic areas of peripheral anterior synechiae. In POAG eyes, anterior uveal trabecular beams were thin and strap-like, while those posteriorly were wide, with a homogenous deposit covering and bridging intertrabecular spaces, especially posteriorly. Underlying corneoscleral trabecular layers and spaces were visualized in some areas. In acute PACG a marked edema of the endothelium probably contributes for the acute and marked intraocular pressure (IOP) elevation. Chronically raised IOP in chronic PACG and POAG probably results, at least in part, from decreased aqueous outflow secondary to widening and fusion of adjacent trabecular beams, together with the homogenous deposit enmeshing trabecular beams and spaces.

Fracture resistance of dental nickel-titanium rotary instruments with novel surface treatment: Thin film metallic glass coating.

PubMed

Chi, Chih-Wen; Deng, Yu-Lun; Lee, Jyh-Wei; Lin, Chun-Pin

2017-05-01

Dental nickel-titanium (NiTi) rotary instruments are widely used in endodontic therapy because they are efficient with a higher success rate. However, an unpredictable fracture of instruments may happen due to the surface characteristics of imperfection (or irregularity). This study assessed whether a novel surface treatment could increase fatigue fracture resistance of dental NiTi rotary instruments. A 200- or 500-nm thick Ti-zirconium-boron (Ti-Zr-B) thin film metallic glass was deposited on ProTaper Universal F2 files using a physical vapor deposition process. The characteristics of coating were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. In cyclic fatigue tests, the files were performed in a simulated root canal (radius=5 mm, angulation=60°) under a rotating speed of 300rpm. The fatigue fractured cross sections of the files were analyzed with their fractographic performances through scanning electron microscopy images. The amorphous structure of the Ti-Zr-B coating was confirmed by transmission electron microscopy and X-ray diffractometry. The surface of treated files presented smooth morphologies without grinding irregularity. For the 200- and 500-nm surface treatment groups, the coated files exhibited higher resistance of cyclic fatigue than untreated files. In fractographic analysis, treated files showed significantly larger crack-initiation zone; however, no significant differences in the areas of fatigue propagation and catastrophic fracture were found compared to untreated files. The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure. Copyright © 2016. Published by Elsevier B.V.

THE FINE STRUCTURE OF MEISSNER's TOUCH CORPUSCLES OF HUMAN FINGERS

PubMed Central

Cauna, Nikolajs; Ross, Leonard L.

1960-01-01

Thin slices of the finger pads of six individuals were fixed in buffered 1 per cent osmic acid, embedded in deaerated, nitrogenated methacrylate, and cut into thin sections for electron microscopic study. Before embedding, the slices were trimmed so as to include several digital tactile corpuscles. Some thin sections were stained in 10 per cent aqueous phosphotungstic acid solution. The principal part of Meissner's corpuscle is made up of flattened laminar cells stretching across the corpuscle in irregular layers. The perinuclear cytoplasm of these cells contains numerous small mitochondria, a sparse granular endoplasmic reticulum, and a large number of small vesicles. Nerve fibers enter the side or base of the corpuscle, lose their myelin sheaths, and follow a meandering course between the laminar cell plates. The nerve endings enter into a close appositional relationship with the flattened portions of the laminar cells. In some areas the apposed axolemma and cell membranes are slightly thickened with small vesicles located along the cell membrane or on both surfaces. These regions are interpreted as synapses. The most prominent feature of the nerve endings is an extraordinary accumulation of small mitochondria which vary in size and internal density. The nerve endings also contain vacuoles, groups of dense concentric membranes, and small dense vesicles of irregular distribution. The laminar cells are separated from one another by a dense intercellular substance of uniform thickness which also envelops the entire corpuscle. This material contains randomly oriented collagen fibers and fine fibrils bound together by a dense material at nodal points recurring at regular intervals of approximately 120 mµ. These findings are discussed in relation to the problems of the function of Meissner's corpuscle, neural material loss and replacement, and the presence of synapses. PMID:13691669

Effect of Resonator Axis Skew on Normal Incidence Impedance

NASA Technical Reports Server (NTRS)

Parrott, Tony L.; Jones, Michael G.; Homeijer, Brian

2003-01-01

High by-pass turbofan engines have fewer fan blades and lower rotation speeds than their predecessors. Consequently, the noise suppression at the low frequency end of the noise spectra has become an increasing concern. This has led to a renewed emphasis on improving noise suppression efficiency of passive, duct liner treatments at the lower frequencies. For a variety of reasons, passive liners are comprised of locally-reacting, resonant absorbers. One reason for this design choice is to satisfy operational and economic requirements. The simplest liner design consists of a single layer of honeycomb core sandwiched between a porous facesheet and an impervious backing plate. These resonant absorbing structures are integrated into the nacelle wall and are very ef- ficient over a limited bandwidth centered on their resonance frequency. Increased noise suppression bandwidth and greater suppression at lower frequencies is typically achieved for conventional liners by increasing the liner depth and incorporating thin porous septa into the honeycomb core. However, constraints on liner depth in modern high by-pass engine nacelles severely limit the suppression bandwidth extension to lower frequencies. Also, current honeycomb core liners may not be suitable for irregular geometric volumes heretofore not considered. It is of interest, therefore, to find ways to circumvent liner depth restrictions and resonator cavity shape constraints. One way to increase effective liner depth is to skew the honeycomb core axis relative to the porous facesheet surface. Other possibilities are to alter resonator cavity shape, e.g. high aspect ratio, narrow channels that possibly include right angle bends, 180. channel fold-backs, and splayed channel walls to conform to irregular geometric constraints. These possibilities constitute the practical motivation for expanding impedance modeling capability to include unconventional resonator orientations and shapes. The work reported in this paper is in the nature of a progress report and is limited to examining the implications of resonator axis skew on the composite normal incidence impedance of an array of resonator channels. Specifically, experimental results are compared with a modified impedance prediction model for highaspect- ratio, rectangular, resonator channels with varying amounts of skew relative to the incident particle velocity. It is shown that for resonator channel widths of 1 to 2 mm, aspect ratios of 25 to 50, and skew angles of zero to sixty degrees, the surface impedance of test models can be predicted with good accuracy. Predicted resistances and reactances are particularly well correlated through the first resonance and first anti-resonance for all six test models investigated. Beyond the first anti-resonance, the impedance prediction model loses the ability to predict details of resistance and reactance but still predicts the mean trends very well.

Some implications of populus intensive culture on nongame birds

Treesearch

Richard L. Verch

1983-01-01

Intensive culture of Populus will affect nongame bird habitat. Conversion of old fields to Populus plantations will destroy habitat favorable to certain species and produce habitat that will attract different species. Effects of this conversion can be lessened by planting plantations with irregular shapes and by leaving patches (.4 hectares) of...

Shallow subsurface drip irrigation (S3DI) for small irregular-shaped fields in the southeast

USDA-ARS?s Scientific Manuscript database

Field tests were conducted using S3DI on cotton (Gossypium hirsutum, L.), corn (Zea mays, L.), and peanut (Arachis hypogeae, L.) rotations to investigate yield potential and economic sustainability of this irrigation system. Drip tubing was installed in alternate row middles, strip tillage was used ...

"Rosetta" Mission's "7 Hours of Terror" and "Philae's" Descent

ERIC Educational Resources Information Center

Blanco, Philip

2015-01-01

In November 2014 the "Rosetta" mission to Comet 67P/Churyumov-Gerasimenko made the headlines when its "Philae" lander completed a successful unpowered descent onto the surface of the comet nucleus after "7 hours of terror" for the mission scientists. 67P's irregular shape and rotation made this task even more…

7 CFR 51.1219 - Well formed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Well formed. 51.1219 Section 51.1219 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Peaches Definitions § 51.1219 Well formed. “Well formed” means that the shape of the peach may be slightly irregular but not to the extent that its...

7 CFR 51.1219 - Well formed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Well formed. 51.1219 Section 51.1219 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Peaches Definitions § 51.1219 Well formed. “Well formed” means that the shape of the peach may be slightly irregular but not to the extent that its...

76 FR 52865 - Special Local Regulations for Marine Events; Patuxent River, Solomons, MD

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-24

... of Transportation, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington... event consists of offshore power boats racing in a counter-clockwise direction on an irregularly-shaped... Private Property This rule will not cause a taking of private property or otherwise have taking...

Special mandrel permits uniform welding of out-of-round tubing

NASA Technical Reports Server (NTRS)

Dor, M. E.; Fueg, L. B.; Whiffen, E. L.

1966-01-01

Clamp holds irregularly shaped pieces in lathe chuck without damage and eliminates excessive time in selecting optimum mounting. Interchangeable jaws ride in standard jaw slots but swivel so that the jaw face bears evenly against the workpiece regardless of contour. The jaws can be used on both engine and turret lathes.

Cotton NDVI response to applied N at different soil EC levels

USDA-ARS?s Scientific Manuscript database

Many fields in the southeastern Coastal Plain are highly variable in soil physical properties and are irregular in shape. These two conditions may make it difficult to determine the ‘best’ area in the field to place nitrogen (N) -rich strips for normalized difference vegetative index (NDVI) -based s...

Development and evaluation of spherical molecularly imprinted polymer beads.

PubMed

Kempe, Henrik; Kempe, Maria

2006-06-01

The majority of studies on molecularly imprinted polymers has until now been carried out on irregularly shaped particles prepared by grinding of polymer monoliths. The preparation procedures are time- and labor-consuming and produce particles of wide size distributions. To answer the need for fast and straightforward routes to spherical molecularly imprinted polymer beads, we have developed a method comprising the formation of droplets of pre-polymerization solution directly in mineral oil by vigorous mixing followed by transformation of the droplets into solid spherical beads by photoinduced free-radical polymerization. No detergents or stabilizers were required for the droplet formation. Factors influencing the bead synthesis have been investigated and are detailed here. The beads were evaluated in parallel with corresponding irregularly shaped particles prepared from polymer monoliths. Conditions for the synthesis of propranolol-imprinted poly(methacrylic acid-co-trimethylolpropane trimethacrylate) beads in the size range of 1-100 microm in almost quantitative yield are described. The beads were applied as the recognition element in a 96-well plate format radioligand assay of propranolol in human serum.

Filler features and their effects on wear and degree of conversion of particulate dental resin composites.

PubMed

Turssi, C P; Ferracane, J L; Vogel, K

2005-08-01

Based on the incomplete understanding on how filler features influence the wear resistance and monomer conversion of resin composites, this study sought to evaluate whether materials containing different shapes and combinations of size of filler particles would perform similarly in terms of three-body abrasion and degree of conversion. Twelve experimental monomodal, bimodal or trimodal composites containing either spherical or irregular shaped fillers ranging from 100 to 1500 nm were examined. Wear testings were conducted in the OHSU wear machine (n = 6) and quantified after 10(5) cycles using a profilometer. Degree of conversion (DC) was measured by FTIR spectrometry at the surface of the composites (n = 6). Data sets were analyzed using one-way Anova and Tukey's test at a significance level of 0.05. Filler size and geometry was found to have a significant effect on wear resistance and DC of composites. At specific sizes and combinations, the presence of small filler particles, either spherical or irregular, may aid in enhancing the wear resistance of composites, without compromising the percentage of reacted carbon double bonds.

Trajectory Design Employing Convex Optimization for Landing on Irregularly Shaped Asteroids

NASA Technical Reports Server (NTRS)

Pinson, Robin M.; Lu, Ping

2016-01-01

Mission proposals that land spacecraft on asteroids are becoming increasingly popular. However, in order to have a successful mission the spacecraft must reliably and softly land at the intended landing site with pinpoint precision. The problem under investigation is how to design a propellant optimal powered descent trajectory that can be quickly computed onboard the spacecraft, without interaction from the ground control. The propellant optimal control problem in this work is to determine the optimal finite thrust vector to land the spacecraft at a specified location, in the presence of a highly nonlinear gravity field, subject to various mission and operational constraints. The proposed solution uses convex optimization, a gravity model with higher fidelity than Newtonian, and an iterative solution process for a fixed final time problem. In addition, a second optimization method is wrapped around the convex optimization problem to determine the optimal flight time that yields the lowest propellant usage over all flight times. Gravity models designed for irregularly shaped asteroids are investigated. Success of the algorithm is demonstrated by designing powered descent trajectories for the elongated binary asteroid Castalia.

Cognitive Distortions Associated with Imagination of the Thin Ideal: Validation of the Thought-Shape Fusion Body Questionnaire (TSF-B)

PubMed Central

Wyssen, Andrea; Debbeler, Luka J.; Meyer, Andrea H.; Coelho, Jennifer S.; Humbel, Nadine; Schuck, Kathrin; Lennertz, Julia; Messerli-Bürgy, Nadine; Biedert, Esther; Trier, Stephan N.; Isenschmid, Bettina; Milos, Gabriella; Whinyates, Katherina; Schneider, Silvia; Munsch, Simone

2017-01-01

Thought-shape fusion (TSF) describes the experience of body-related cognitive distortions associated with eating disorder (ED) pathology. In the laboratory TSF has been activated by thoughts about fattening/forbidden foods and thin ideals. This study aims at validating a questionnaire to assess the trait susceptibility to TSF (i.e., body-related cognitive distortions) associated with the imagination of thin ideals, and developing an adapted version of the original TSF trait questionnaire, the Thought-Shape Fusion Body Questionnaire (TSF-B). Healthy control women (HC, n = 317) and women diagnosed with subthreshold and clinical EDs (n = 243) completed an online-questionnaire. The factor structure of the TSF-B questionnaire was examined using exploratory (EFA) and subsequent confirmatory factor analysis (CFA). EFA pointed to a two-factor solution, confirmed by CFA. Subscale 1 was named Imagination of thin ideals, containing five items referring to the imagination of female thin ideals. Subscale 2 was named Striving for own thin ideal, with seven items about pursuing/abandoning attempts to reach one’s own thin ideal. The total scale and both subscales showed good convergent validity, excellent reliability, and good ability to discriminate between individuals with subthreshold/clinical EDs and HCs. Results indicate that cognitive distortions are also related to the imagination of thin ideals, and are associated with ED pathology. With two subscales, the TSF-B trait questionnaire appropriately measures this construct. Future studies should clarify whether TSF-B is predictive for the development and course of EDs. Assessing cognitive distortions with the TSF-B questionnaire could improve understanding of EDs and stimulate the development of cognitively oriented interventions. Clinical Trial Registration Number: DRKS-ID: DRKS00005709. PMID:29312059

Tearing as a test for mechanical characterization of thin adhesive films

NASA Astrophysics Data System (ADS)

Hamm, Eugenio; Reis, Pedro; Leblanc, Michael; Roman, Benoit; Cerda, Enrique

2008-05-01

Thin adhesive films have become increasingly important in applications involving packaging, coating or for advertising. Once a film is adhered to a substrate, flaps can be detached by tearing and peeling, but they narrow and collapse in pointy shapes. Similar geometries are observed when peeling ultrathin films grown or deposited on a solid substrate, or skinning the natural protective cover of a ripe fruit. Here, we show that the detached flaps have perfect triangular shapes with a well-defined vertex angle; this is a signature of the conversion of bending energy into surface energy of fracture and adhesion. In particular, this triangular shape of the tear encodes the mechanical parameters related to these three forms of energy and could form the basis of a quantitative assay for the mechanical characterization of thin adhesive films, nanofilms deposited on substrates or fruit skin.

Tearing as a test for mechanical characterization of thin adhesive films.

PubMed

Hamm, Eugenio; Reis, Pedro; LeBlanc, Michael; Roman, Benoit; Cerda, Enrique

2008-05-01

Thin adhesive films have become increasingly important in applications involving packaging, coating or for advertising. Once a film is adhered to a substrate, flaps can be detached by tearing and peeling, but they narrow and collapse in pointy shapes. Similar geometries are observed when peeling ultrathin films grown or deposited on a solid substrate, or skinning the natural protective cover of a ripe fruit. Here, we show that the detached flaps have perfect triangular shapes with a well-defined vertex angle; this is a signature of the conversion of bending energy into surface energy of fracture and adhesion. In particular, this triangular shape of the tear encodes the mechanical parameters related to these three forms of energy and could form the basis of a quantitative assay for the mechanical characterization of thin adhesive films, nanofilms deposited on substrates or fruit skin.

Multicolor Layer-by-Layer films using weak polyelectrolyte assisted synthesis of silver nanoparticles

NASA Astrophysics Data System (ADS)

Rivero, Pedro Jose; Goicoechea, Javier; Urrutia, Aitor; Matias, Ignacio Raul; Arregui, Francisco Javier

2013-10-01

In the present study, we show that silver nanoparticles (AgNPs) with different shape, aggregation state and color (violet, green, orange) have been successfully incorporated into polyelectrolyte multilayer thin films using the layer-by-layer (LbL) assembly. In order to obtain colored thin films based on AgNPs is necessary to maintain the aggregation state of the nanoparticles, a non-trivial aspect in which this work is focused on. The use of Poly(acrylic acid, sodium salt) (PAA) as a protective agent of the AgNPs is the key element to preserve the aggregation state and makes possible the presence of similar aggregates (shape and size) within the LbLcolored films. This approach based on electrostatic interactions of the polymeric chains and the immobilization of AgNPs with different shape and size into the thin films opens up a new interesting perspective to fabricate multicolornanocomposites based on AgNPs.

Templated Solid-State Dewetting of Thin Silicon Films.

PubMed

Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Delobbe, Anne; Ronda, Antoine; Berbezier, Isabelle; Abbarchi, Marco

2016-11-01

Thin film dewetting can be efficiently exploited for the implementation of functionalized surfaces over very large scales. Although the formation of sub-micrometer sized crystals via solid-state dewetting represents a viable method for the fabrication of quantum dots and optical meta-surfaces, there are several limitations related to the intrinsic features of dewetting in a crystalline medium. Disordered spatial organization, size, and shape fluctuations are relevant issues not properly addressed so far. This study reports on the deterministic nucleation and precise positioning of Si- and SiGe-based nanocrystals by templated solid-state dewetting of thin silicon films. The dewetting dynamics is guided by pattern size and shape taking full control over number, size, shape, and relative position of the particles (islands dimensions and relative distances are in the hundreds nm range and fluctuate ≈11% for the volumes and ≈5% for the positioning). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multicolor Layer-by-Layer films using weak polyelectrolyte assisted synthesis of silver nanoparticles

PubMed Central

2013-01-01

In the present study, we show that silver nanoparticles (AgNPs) with different shape, aggregation state and color (violet, green, orange) have been successfully incorporated into polyelectrolyte multilayer thin films using the layer-by-layer (LbL) assembly. In order to obtain colored thin films based on AgNPs is necessary to maintain the aggregation state of the nanoparticles, a non-trivial aspect in which this work is focused on. The use of Poly(acrylic acid, sodium salt) (PAA) as a protective agent of the AgNPs is the key element to preserve the aggregation state and makes possible the presence of similar aggregates (shape and size) within the LbLcolored films. This approach based on electrostatic interactions of the polymeric chains and the immobilization of AgNPs with different shape and size into the thin films opens up a new interesting perspective to fabricate multicolornanocomposites based on AgNPs. PMID:24148227

Thin sheets achieve optimal wrapping of liquids

NASA Astrophysics Data System (ADS)

Paulsen, Joseph; Démery, Vincent; Davidovitch, Benny; Santangelo, Christian; Russell, Thomas; Menon, Narayanan

2015-03-01

A liquid drop can wrap itself in a sheet using capillary forces [Py et al., PRL 98, 2007]. However, the efficiency of ``capillary origami'' at covering the surface of a drop is hampered by the mechanical cost of bending the sheet. Thinner sheets deform more readily by forming small-scale wrinkles and stress-focussing patterns, but it is unclear how coverage efficiency competes with mechanical cost as thickness is decreased, and what wrapping shapes will emerge. We place a thin (~ 100 nm) polymer film on a drop whose volume is gradually decreased so that the sheet covers an increasing fraction of its surface. The sheet exhibits a complex sequence of axisymmetric and polygonal partially- and fully- wrapped shapes. Remarkably, the progression appears independent of mechanical properties. The gross shape, which neglects small-scale features, is correctly predicted by a simple geometric approach wherein the exposed area is minimized. Thus, simply using a thin enough sheet results in maximal coverage.

Shape, Density, and Geology of the Nucleus of Comet 103P/Hartley 2

NASA Technical Reports Server (NTRS)

Thomas, P.C.; A'hearn, Michael F.; Veverka, Joseph; Belton, Michael J. S.; Kissel, Jochen; Belton, Michael J. S.; Klaasen, Kenneth P.; McFadden, Lucy A.; Melosh, H. Jay; Schultz, Peter H.;

Method and apparatus for detecting irregularities on or in the wall of a vessel

DOEpatents

Bowling, Michael Keith

2000-09-12

A method of detecting irregularities on or in the wall of a vessel by detecting localized spatial temperature differentials on the wall surface, comprising scanning the vessel surface with a thermal imaging camera and recording the position of the or each region for which the thermal image from the camera is indicative of such a temperature differential across the region. The spatial temperature differential may be formed by bacterial growth on the vessel surface; alternatively, it may be the result of defects in the vessel wall such as thin regions or pin holes or cracks. The detection of leaks through the vessel wall may be enhanced by applying a pressure differential or a temperature differential across the vessel wall; the testing for leaks may be performed with the vessel full or empty, and from the inside or the outside.

Confined disclinations: exterior versus material constraints in developable thin elastic sheets.

PubMed

Efrati, Efi; Pocivavsek, Luka; Meza, Ruben; Lee, Ka Yee C; Witten, Thomas A

2015-02-01

We examine the shape change of a thin disk with an inserted wedge of material when it is pushed against a plane, using analytical, numerical, and experimental methods. Such sheets occur in packaging, surgery, and nanotechnology. We approximate the sheet as having vanishing strain, so that it takes a conical form in which straight generators converge to a disclination singularity. Then, its shape is that which minimizes elastic bending energy alone. Real sheets are expected to approach this limiting shape as their thickness approaches zero. The planar constraint forces a sector of the sheet to buckle into the third dimension. We find that the unbuckled sector is precisely semicircular, independent of the angle δ of the inserted wedge. We generalize the analysis to include conical as well as planar constraints and thereby establish a law of corresponding states for shallow cones of slope ε and thin wedges. In this regime, the single parameter δ/ε^{2} determines the shape. We discuss the singular limit in which the cone becomes a plane, and the unexpected slow convergence to the semicircular buckling observed in real sheets.

Confined disclinations: Exterior versus material constraints in developable thin elastic sheets

NASA Astrophysics Data System (ADS)

Efrati, Efi; Pocivavsek, Luka; Meza, Ruben; Lee, Ka Yee C.; Witten, Thomas A.

2015-02-01

We examine the shape change of a thin disk with an inserted wedge of material when it is pushed against a plane, using analytical, numerical, and experimental methods. Such sheets occur in packaging, surgery, and nanotechnology. We approximate the sheet as having vanishing strain, so that it takes a conical form in which straight generators converge to a disclination singularity. Then, its shape is that which minimizes elastic bending energy alone. Real sheets are expected to approach this limiting shape as their thickness approaches zero. The planar constraint forces a sector of the sheet to buckle into the third dimension. We find that the unbuckled sector is precisely semicircular, independent of the angle δ of the inserted wedge. We generalize the analysis to include conical as well as planar constraints and thereby establish a law of corresponding states for shallow cones of slope ɛ and thin wedges. In this regime, the single parameter δ /ɛ2 determines the shape. We discuss the singular limit in which the cone becomes a plane, and the unexpected slow convergence to the semicircular buckling observed in real sheets.

A new spinner magnetometer using high sensitivity magneto-impedance sensor

NASA Astrophysics Data System (ADS)

Kodama, Kazuto

2016-04-01

A sensitive spinner magnetometer was developed using a pair of high-resolution Magneto-Impedance sensors. The MI sensor generally utilizes the MI effect of amorphous wire whose impedance changes by the application of a small magnetic field. Various kinds of MI sensors are currently used in many electric devices, for example, a magnetic compass chip built-in smart phones and car navigations. The MI sensor employed in this study is a pico-Tesla MI sensor, an especially sensitive MI sensor originally manufactured for industrial use to detect contamination of small magnetic particles in industrial materials such as fabrics. To detect weak magnetic signals from natural samples and avoid DC drift, a gradiometer system was employed that consists of a pair of the MI sensors and the electronics with analog filter and pre-amplification circuit. This MI gradiometer system was equipped to a commercial spinner magnetometer (SMD-88, Natsuhara Giken, Osaka) with the spinning rate of 5 Hz. It is demonstrated that this new spinner magnetometer is capable of measuring weak magnetic samples of 10-6 mAm2, with the highest resolution being 10-8 mAm2, approximately two orders of magnitude better than the previous one using a ring-core flux-gate sensor. One of the advantages of the MI spinner magnetometer is that it can be easily modified to accommodate samples of any shape and size. Moreover the slow-rotating speed (5 Hz) allows to measure samples for archeomagnetic studies that are usually irregular and fragile. Because the irregularity of shape increases errors in measuring the dipole component of the total magnetization, it is necessary to increase the distance between the sample and sensor, resulting in poorer sensitivity. The high-sensitivity MI sensor enables to measure the NRM of such irregular-shaped samples from an appropriate distance to the sample, with no significant loss of sensitivity.

Liver anatomy, histochemistry, and ultrastructure of Eupemphix nattereri (Anura: Leiuperidae) during the breeding season.

PubMed

Franco-Belussi, Lilian; Santos, Lia Raquel de Souza; Zieri, Rodrigo; Vicentini, Carlos Alberto; Taboga, Sebastião Roberto; de Oliveira, Classius

2012-12-01

The arrangement of the hepatic tissue is directly related to physiological characteristics of animals, such as ectothermy, diet, and reproductive status. Here, we describe the anatomy, histology, and ultrastructure of the liver in adult males of Eupemphix nattereri during the breeding season. The liver is an organ with an irregular shape, red in color, and occupies a large portion of the body cavity. Anatomically, it is divided into three lobes: right, mid, and left. Further subdivision into lobules is not observed. A thin capsule of connective tissue covers externally the organ, which is responsible for its support and protection. The hepatic parenchyma is formed by two layers of polyhedralshaped hepatocytes arranged in a double cordon. These cordons are filled with hepatic sinusoids that greatly vary in size and are closely associated with hepatocytes. There are also bile canaliculi and immune cells between hepatic cordons-the melanomacrophages. These canaliculi are covered with short microvilli, which protrude into the lumen. Melanomacrophages have several cytoplasmic substances, such as melanin, lipofuscin, and hemosiderin, which form due to liver metabolism and contribute to the typical coloration of the organ. A large amount of mitochondria and other organelles, such as a well-developed Golgi apparatus, smooth endoplasmic reticulum, and abundant glycogen are found in the cytoplasm of hepatocytes.

Optical Forging of Graphene into Three-Dimensional Shapes.

PubMed

Johansson, Andreas; Myllyperkiö, Pasi; Koskinen, Pekka; Aumanen, Jukka; Koivistoinen, Juha; Tsai, Hung-Chieh; Chen, Chia-Hao; Chang, Lo-Yueh; Hiltunen, Vesa-Matti; Manninen, Jyrki J; Woon, Wei Yen; Pettersson, Mika

2017-10-11

Atomically thin materials, such as graphene, are the ultimate building blocks for nanoscale devices. But although their synthesis and handling today are routine, all efforts thus far have been restricted to flat natural geometries, since the means to control their three-dimensional (3D) morphology has remained elusive. Here we show that, just as a blacksmith uses a hammer to forge a metal sheet into 3D shapes, a pulsed laser beam can forge a graphene sheet into controlled 3D shapes in the nanoscale. The forging mechanism is based on laser-induced local expansion of graphene, as confirmed by computer simulations using thin sheet elasticity theory.

An analytical method to calculate equivalent fields to irregular symmetric and asymmetric photon fields.

PubMed

Tahmasebi Birgani, Mohamad J; Chegeni, Nahid; Zabihzadeh, Mansoor; Hamzian, Nima

2014-01-01

Equivalent field is frequently used for central axis depth-dose calculations of rectangular- and irregular-shaped photon beams. As most of the proposed models to calculate the equivalent square field are dosimetry based, a simple physical-based method to calculate the equivalent square field size was used as the basis of this study. The table of the sides of the equivalent square or rectangular fields was constructed and then compared with the well-known tables by BJR and Venselaar, et al. with the average relative error percentage of 2.5 ± 2.5% and 1.5 ± 1.5%, respectively. To evaluate the accuracy of this method, the percentage depth doses (PDDs) were measured for some special irregular symmetric and asymmetric treatment fields and their equivalent squares for Siemens Primus Plus linear accelerator for both energies, 6 and 18MV. The mean relative differences of PDDs measurement for these fields and their equivalent square was approximately 1% or less. As a result, this method can be employed to calculate equivalent field not only for rectangular fields but also for any irregular symmetric or asymmetric field. © 2013 American Association of Medical Dosimetrists Published by American Association of Medical Dosimetrists All rights reserved.

Thin-Film Nanocapacitor and Its Characterization

ERIC Educational Resources Information Center

Hunter, David N.; Pickering, Shawn L.; Jia, Dongdong

2007-01-01

An undergraduate thin-film nanotechnology laboratory was designed. Nanocapacitors were fabricated on silicon substrates by sputter deposition. A mask was designed to form the shape of the capacitor and its electrodes. Thin metal layers of Au with a 80 nm thickness were deposited and used as two infinitely large parallel plates for a capacitor.…

Manufacture of Regularly Shaped Sol-Gel Pellets

NASA Technical Reports Server (NTRS)

Leventis, Nicholas; Johnston, James C.; Kinder, James D.

2006-01-01

An extrusion batch process for manufacturing regularly shaped sol-gel pellets has been devised as an improved alternative to a spray process that yields irregularly shaped pellets. The aspect ratio of regularly shaped pellets can be controlled more easily, while regularly shaped pellets pack more efficiently. In the extrusion process, a wet gel is pushed out of a mold and chopped repetitively into short, cylindrical pieces as it emerges from the mold. The pieces are collected and can be either (1) dried at ambient pressure to xerogel, (2) solvent exchanged and dried under ambient pressure to ambigels, or (3) supercritically dried to aerogel. Advantageously, the extruded pellets can be dropped directly in a cross-linking bath, where they develop a conformal polymer coating around the skeletal framework of the wet gel via reaction with the cross linker. These pellets can be dried to mechanically robust X-Aerogel.

Analysis of the shapes of hemocytes of Callista brevisiphonata in vitro (Bivalvia, Veneridae).

PubMed

Karetin, Yu A; Pushchin, I I

2015-08-01

Fractal formalism in conjunction with linear methods of image analysis is suitable for the comparative analysis of such "irregular" shapes (from the point of view of classical Euclidean geometry) as flattened amoeboid cells of invertebrates in vitro. Cell morphology of in vitro spreading hemocytes from the bivalve mollusc Callista brevisiphonata was analyzed using correlation, factor and cluster analysis. Four significantly different cell types were identified on the basis of 36 linear and nonlinear parameters. The analysis confirmed the adequacy of the selected methodology for numerical description of the shape and the adequacy of classification of nonlinear shapes of spread hemocytes belonging to the same species. Investigation has practical significance for the description of the morphology of cultured cells, since cell shape is a result of summation of a number of extracellular and intracellular factors. © 2015 International Society for Advancement of Cytometry.

Barium ferrite thin-film recording media

NASA Astrophysics Data System (ADS)

Sui, Xiaoyu; Scherge, Matthias; Kryder, Mark H.; Snyder, John E.; Harris, Vincent G.; Koon, Norman C.

1996-03-01

Both longitudinal and perpendicular barium ferrite thin films are being pursued as overcoatless magnetic recording media. In this paper, prior research on thin-film Ba ferrite is reviewed and the most recent results are presented. Self-textured high-coercivity longitudinal Ba ferrite thin films have been achieved using conventional rf diode sputtering. Microstructural studies show that c-axis in-plane oriented grains have a characteristic acicular shape, while c-axis perpendicularly oriented grains have a platelet shape. Extended X-ray absorption fine structure (EXAFS) measurements indicate that the crystal orientations are predetermined by the structural anisotropy in the as-sputtered 'amorphous' state. Recording tests on 1500 Oe coercivity longitudinal Ba ferrite disks show performance comparable with that of a 1900 Oe Co alloy disk. To further improve the recording performance, both grain size and aspect ratio need to be reduced. Initial tribological tests indicate high hardness of Ba ferrite thin films. However, surface roughness needs to be reduced. For future ultrahigh-density contact recording, it is believed that perpendicular recording may be used. A thin Pt underlayer has been found to be capable of producing Ba ferrite thin films with excellent c-axis perpendicular orientation.

Study of various synthesis techniques of nanomaterials

NASA Astrophysics Data System (ADS)

Patil, Madhuri; Sharma, Deepika; Dive, Avinash; Mahajan, Sandeep; Sharma, Ramphal

2018-05-01

Development of synthesis techniques of realizing nano-materials over a range of sizes, shapes, and chemical compositions is an important aspect of nanotechnology. The remarkable size dependent physical & chemical properties of particles have fascinated and inspired research activity in this direction. This paper describes some aspects on synthesis and characterization of particles of metals, metal alloys, and oxides, either in the form of thin films or bulk shapes. A brief discussion on processing of thin-films is also described.

Nucleoli in human early erythroblasts (K2, K1, K1/2 cells).

PubMed

Smetana, K; Jirásková, I; Klamová, H

2005-01-01

Human early erythroid precursors classified according to the nuclear size were studied to provide information on nucleoli in these cells using simple cytochemical procedures for demonstration of RNA and proteins of silver-stained nucleolar organizers. K2 cells with nuclear diameter larger than 13 microm and K1 cells with nuclear diameter larger than 9 microm corresponding to proerythroblasts and macroblasts (large basophilic erythroblasts) mostly possessed large irregularly shaped nucleoli with multiple fibrillar centres representing "active nucleoli". K1/2 cells with nuclear diameter smaller than 9 microm corresponding to small basophilic erythroblasts were usually characterized by the presence of micronucleoli representing "inactive nucleolar types". On the other hand, a few K1/2 cells contained large nucleoli with multiple fibrillar centres similar to those present in K2 cells and thus appeared as "microproerythroblasts". The nucleolar asynchrony expressed by the presence of large irregularly shaped nucleoli with multiple nucleoli (active nucleoli) and ring-shaped nucleoli (resting nucleoli) in one and the same nucleus of K2 or K1 cells was not exceptional and might reflect a larger resistance of these cells to negative factors influencing the erythropoiesis. The intranucleolar translocation of silver-stained nucleolus organized regions was noted in K2 cells and might indicate the premature aging of these cells without further differentiation. More studies, however, are required in this direction.

A Novel Method of Aircraft Detection Based on High-Resolution Panchromatic Optical Remote Sensing Images.

PubMed

Wang, Wensheng; Nie, Ting; Fu, Tianjiao; Ren, Jianyue; Jin, Longxu

2017-05-06

In target detection of optical remote sensing images, two main obstacles for aircraft target detection are how to extract the candidates in complex gray-scale-multi background and how to confirm the targets in case the target shapes are deformed, irregular or asymmetric, such as that caused by natural conditions (low signal-to-noise ratio, illumination condition or swaying photographing) and occlusion by surrounding objects (boarding bridge, equipment). To solve these issues, an improved active contours algorithm, namely region-scalable fitting energy based threshold (TRSF), and a corner-convex hull based segmentation algorithm (CCHS) are proposed in this paper. Firstly, the maximal variance between-cluster algorithm (Otsu's algorithm) and region-scalable fitting energy (RSF) algorithm are combined to solve the difficulty of targets extraction in complex and gray-scale-multi backgrounds. Secondly, based on inherent shapes and prominent corners, aircrafts are divided into five fragments by utilizing convex hulls and Harris corner points. Furthermore, a series of new structure features, which describe the proportion of targets part in the fragment to the whole fragment and the proportion of fragment to the whole hull, are identified to judge whether the targets are true or not. Experimental results show that TRSF algorithm could improve extraction accuracy in complex background, and that it is faster than some traditional active contours algorithms. The CCHS is effective to suppress the detection difficulties caused by the irregular shape.

Automated Segmentation of Nuclei in Breast Cancer Histopathology Images.

PubMed

Paramanandam, Maqlin; O'Byrne, Michael; Ghosh, Bidisha; Mammen, Joy John; Manipadam, Marie Therese; Thamburaj, Robinson; Pakrashi, Vikram

2016-01-01

The process of Nuclei detection in high-grade breast cancer images is quite challenging in the case of image processing techniques due to certain heterogeneous characteristics of cancer nuclei such as enlarged and irregularly shaped nuclei, highly coarse chromatin marginalized to the nuclei periphery and visible nucleoli. Recent reviews state that existing techniques show appreciable segmentation accuracy on breast histopathology images whose nuclei are dispersed and regular in texture and shape; however, typical cancer nuclei are often clustered and have irregular texture and shape properties. This paper proposes a novel segmentation algorithm for detecting individual nuclei from Hematoxylin and Eosin (H&E) stained breast histopathology images. This detection framework estimates a nuclei saliency map using tensor voting followed by boundary extraction of the nuclei on the saliency map using a Loopy Back Propagation (LBP) algorithm on a Markov Random Field (MRF). The method was tested on both whole-slide images and frames of breast cancer histopathology images. Experimental results demonstrate high segmentation performance with efficient precision, recall and dice-coefficient rates, upon testing high-grade breast cancer images containing several thousand nuclei. In addition to the optimal performance on the highly complex images presented in this paper, this method also gave appreciable results in comparison with two recently published methods-Wienert et al. (2012) and Veta et al. (2013), which were tested using their own datasets.

Automated Segmentation of Nuclei in Breast Cancer Histopathology Images

PubMed Central

Paramanandam, Maqlin; O’Byrne, Michael; Ghosh, Bidisha; Mammen, Joy John; Manipadam, Marie Therese; Thamburaj, Robinson; Pakrashi, Vikram

2016-01-01

The process of Nuclei detection in high-grade breast cancer images is quite challenging in the case of image processing techniques due to certain heterogeneous characteristics of cancer nuclei such as enlarged and irregularly shaped nuclei, highly coarse chromatin marginalized to the nuclei periphery and visible nucleoli. Recent reviews state that existing techniques show appreciable segmentation accuracy on breast histopathology images whose nuclei are dispersed and regular in texture and shape; however, typical cancer nuclei are often clustered and have irregular texture and shape properties. This paper proposes a novel segmentation algorithm for detecting individual nuclei from Hematoxylin and Eosin (H&E) stained breast histopathology images. This detection framework estimates a nuclei saliency map using tensor voting followed by boundary extraction of the nuclei on the saliency map using a Loopy Back Propagation (LBP) algorithm on a Markov Random Field (MRF). The method was tested on both whole-slide images and frames of breast cancer histopathology images. Experimental results demonstrate high segmentation performance with efficient precision, recall and dice-coefficient rates, upon testing high-grade breast cancer images containing several thousand nuclei. In addition to the optimal performance on the highly complex images presented in this paper, this method also gave appreciable results in comparison with two recently published methods—Wienert et al. (2012) and Veta et al. (2013), which were tested using their own datasets. PMID:27649496

Equilibrium shapes and surface selection of nanostructures in 6H-SiC

DOE PAGES

Kondo, Sosuke; Parish, Chad M.; Koyanagi, Takaaki; ...

2017-04-03

Here, the equilibrium shape of 6H-SiC nanostructures and their surfaces were studied by analyzing nano-void (~10 nm) shapes, which were introduced in monocrystalline 6H-SiC by high-temperature neutron irradiation, using transmission electron microscopy. The nano-voids were determined to be irregular icosahedrons truncated with six {1¯100}, twelve {1¯103}, one smaller top-basal, and one larger bottom-basal planes, which suggests that {1¯100} and {1¯103} are the next stable surface class after the basal planes. The relatively frequent absence of the {1¯100} surface in the nano-voids indicated that the (1¯103¯) surface type is energetically rather stable. These non-basal surfaces were found not to be atomicallymore » flat due to the creation of nanofacets with half unit-cell height in the c-axis. The {1¯100} and {1¯103} surfaces were classified as two and four face types according to their possible nanofacets and surface termination, respectively. We also discuss the surface energy difference between the (1¯103¯) and (1¯103) face types in relation to the energy balance within the equilibrium, but irregular, polyhedron, in which the (1¯103) surface had double the surface energy of the (1¯103¯) surface (~3900 erg/cm 2).« less

Computed Tomography Angiography Evaluation of Risk Factors for Unstable Intracranial Aneurysms.

PubMed

Wang, Guang-Xian; Gong, Ming-Fu; Wen, Li; Liu, Lan-Lan; Yin, Jin-Bo; Duan, Chun-Mei; Zhang, Dong

2018-03-19

To evaluate risk factors for instability in intracranial aneurysms (IAs) using computed tomography angiography (CTA). A total of 614 consecutive patients diagnosed with 661 IAs between August 2011 and February 2016 were reviewed. Patients and IAs were divided into stable and unstable groups. Along with clinical characteristics, IA characteristics were evaluated by CTA. Multiple logistic regression analysis was used to identify the independent risk factors associated with unstable IAs. Receiver operating characteristic (ROC) curve analysis was performed on the final model, and optimal thresholds were obtained. Patient age (odds ratio [OR], 0.946), cerebral atherosclerosis (CA; OR, 0.525), and IAs located at the middle cerebral artery (OR, 0.473) or internal carotid artery (OR, 0.512) were negatively correlated with instability, whereas IAs with irregular shape (OR, 2.157), deep depth (OR, 1.557), or large flow angle (FA; OR, 1.015) were more likely to be unstable. ROC analysis revealed threshold values of age, depth, and FA of 59.5 years, 4.25 mm, and 87.8°, respectively. The stability of IAs is significantly affected by several factors, including patient age and the presence of CA. IA shape and location also have an impact on the stability of IAs. Growth into an irregular shape, with a deep depth, and a large FA are risk factors for a change in IAs from stable to unstable. Copyright © 2018 Elsevier Inc. All rights reserved.

The Irregular Moons of Saturn

NASA Astrophysics Data System (ADS)

Denk, Tilmann; Mottola, Stefano; Tosi, Federico; Bottke, William; Hamilton, Douglas P.

2017-10-01

The 38 irregular moons of Saturn, all but Phoebe discovered between 2000 and 2007, outnumber the planet's classical satellites. Observations from the ground and from near-Earth space have revealed orbits, sizes, and colors and have hinted at the existence of dynamical families, indicative of collisional evolution and common progenitors. More recently, remote observations of many irregular satellites with the Cassini spacecraft produced lightcurves that helped determine rotational periods, coarse shape models, potential hemispheric color heterogeneities, and other basic properties.From Cassini, a total of 25 Saturnian irregulars have been observed with the ISS camera. Their rotational periods range from 5.45 h to 76.13 h. The absence of fast rotators is evident. Among main-belt asteroids of the same size range (~4 to ~45 km), one third of the objects have faster rotations, indicating that many irregulars should be low-density objects.While the origin of the irregulars is still debated, capture of comets via three-body interactions during giant planets encounters does the best job thus far at reproducing the observed prograde/retrograde orbits. Data from the ground, near-Earth spacecraft, and Cassini as well as modeling results suggest the population visible today has experienced substantial collisional evolution. It may be that only Phoebe has survived relatively intact. The small particle debris drifts toward Saturn by P-R drag, with most of it swept up by Titan. Only remnants of this process are visible today.Our current knowledge on the Saturnian irregulars will be summarized in a chapter [1] in the book "Enceladus and the Icy Moons of Saturn" [2]. The talk will give an overview on the chapter's content, which covers the following topics: Orbital "architecture" (a,e,i), sizes and colors, Cassini observations and results, Phoebe, origin, an outlook.[1] Denk, T., Mottola, S., Tosi, F., Bottke, W.F., Hamilton, D.P. (2018): The Irregular Satellites of Saturn. In: Enceladus and the Icy Moons of Saturn (Schenk, P. et al., eds.), Space Science Series, The University of Arizona Press. In press.[2] See http://www.uapress.arizona.edu/Books/bid2726.htm

An exploration of the influence of thinness expectancies and eating pathology on compensatory exercise.

PubMed

Garner, Ashton; Davis-Becker, Kendra; Fischer, Sarah

2014-08-01

Compensatory exercise (exercise performed in an effort to control weight/shape or in response to caloric intake) and thinness expectancies (beliefs that thinness will improve the overall quality of life) are strongly linked to the development, maintenance, severity, and outcome of eating disorders. There is little literature, however, examining the relationship between compensatory exercise and thinness expectancies. The goal of the current study was to examine whether thinness expectancies contribute significant variance in the endorsement of excessive exercise over and above binge eating, restraint, and shape and weight concerns. A total of 677 undergraduate women (mean age=18.73) completed self-report measures of thinness expectancies and eating disorder symptoms (TREI and EDE-Q). There was a significant association between thinness expectancies and frequency of compensatory exercise behavior. Restraint and subjective binge episodes accounted for significant variance in compensatory exercise. Frequency of objective binge episodes did not, nor did endorsement of thinness expectancies. These findings suggest a potential profile of individuals engaging in compensatory exercise as individuals who actively restrict their diets, feel as if they have binged when they violate those restrictions, and feel the need to excessively exercise to compensate for the subjective binges. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

DOEpatents

Ardary, Z.L.; Benton, S.T.

1987-07-08

The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

DOEpatents

Ardary, Zane L.; Benton, Samuel T.

1988-01-01

The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

DOEpatents

Ardary, Z.L.; Benton, S.T.

1988-11-22

The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Identification and Characterization of Pseudocercospora pyricola Causing Leaf Spots on Aronia melanocarpa.

PubMed

Park, Sung-Hee; Choi, In-Young; Seo, Kyoung-Won; Kim, Jin-Ho; Galea, Victor; Shin, Hyeon-Dong

2017-03-01

Leaf spot disease on black chokeberry ( Aronia melanocarpa ) was observed at several locations in Korea during 2014-2015. Leaf spots were distinct, scattered over the leaf surface and along the leaf border, subcircular to irregular and brown surrounded by a distinct dark color, and were expanded and coalesced into irregularly shaped lesions. Severely infected leaves became dry and fell off eventually. The causative agent was identified as Pseudocercospora pyricola . Morphological observations and phylogenetic analyses of multiple genes, including internal transcribed spacer, translation elongation factor 1-alpha, actin, and the large subunit ribosomal DNA were conducted. The pathogenicity test was conducted twice yielding similar results, fulfilling Koch's postulates. To our knowledge, this is the first report on P. pyricola infection of A. melanocarpa globally.

Method of casting silicon into thin sheets

DOEpatents

Sanjurjo, Angel; Rowcliffe, David J.; Bartlett, Robert W.

1982-10-26

Silicon (Si) is cast into thin shapes within a flat-bottomed graphite crucible by providing a melt of molten Si along with a relatively small amount of a molten salt, preferably NaF. The Si in the resulting melt forms a spherical pool which sinks into and is wetted by the molten salt. Under these conditions the Si will not react with any graphite to form SiC. The melt in the crucible is pressed to the desired thinness with a graphite tool at which point the tool is held until the mass in the crucible has been cooled to temperatures below the Si melting point, at which point the Si shape can be removed.

Experimental and LES investigation of premixed methane/air flame propagating in a tube with a thin obstacle

NASA Astrophysics Data System (ADS)

Chen, Peng; Guo, Shilong; Li, Yanchao; Zhang, Yutao

2017-03-01

In this paper, an experimental and numerical investigation of premixed methane/air flame dynamics in a closed combustion vessel with a thin obstacle is described. In the experiment, high-speed video photography and a pressure transducer are used to study the flame shape changes and pressure dynamics. In the numerical simulation, four sub-grid scale viscosity models and three sub-grid scale combustion models are evaluated for their individual prediction compared with the experimental data. High-speed photographs show that the flame propagation process can be divided into five stages: spherical flame, finger-shaped flame, jet flame, mushroom-shaped flame and bidirectional propagation flame. Compared with the other sub-grid scale viscosity models and sub-grid scale combustion models, the dynamic Smagorinsky-Lilly model and the power-law flame wrinkling model are better able to predict the flame behaviour, respectively. Thus, coupling the dynamic Smagorinsky-Lilly model and the power-law flame wrinkling model, the numerical results demonstrate that flame shape change is a purely hydrodynamic phenomenon, and the mushroom-shaped flame and bidirectional propagation flame are the result of flame-vortex interaction. In addition, the transition from "corrugated flamelets" to "thin reaction zones" is observed in the simulation.

Influence of edging practices on cutting yields of Alaska birch lumber

Treesearch

David L. Nicholls; J.W. Funck; C.C. Brunner; J.E. Reeb

2009-01-01

Birch lumber is often characterized by a high degree of knots, bark pockets, heartwood, and other features which force sawmill owners to decide whether to edge and trim boards to produce standard grade lumber vs. proprietary grade character-marked lumber. In addition, the edging strategies used with irregularly shaped flitches can greatly influence cut-stock recovery....

Saturn: Origin and composition of its inner moons and rings

NASA Technical Reports Server (NTRS)

Prentice, A. J. R.

1980-01-01

The contraction of the primitive protosaturnian cloud, using ideas of supersonic turbulent convection was modeled. The model suggested that each of Saturn's inner moons, excepting Rhea, condensed above the ice-point of water and consists primarily of hydrous magnesium silicates. The satellite mean densities steadily increase towards the planet and the rocky moons are irregular in shape.

Finding the Center of Volume of the Forearm

ERIC Educational Resources Information Center

Klein, Stacy S.; Roselli, Robert J.

2008-01-01

A typical first-year physics course teaches students about the center of mass using both regular and irregularly shaped objects. Students often suspend an object in each of two dimensions from a string with the intersection determining the center of mass of the object. While these methods can be effective, they are not particularly exciting or…

Water content measurement in forest soils and decayed wood using time domain reflectometry

Treesearch

Andrew Gray; Thomas Spies

1995-01-01

The use of time domain reflectometry to measure moisture content in forest soils and woody debris was evaluated. Calibrations were developed on undisturbed soil cores from four forest stands and on point samples from decayed logs. An algorithm for interpreting irregularly shaped traces generated by the reflectometer was also developed. Two different calibration...

77 FR 47279 - Special Local Regulations for Marine Events, Patuxent River; Solomons, MD

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

... Management Facility in Room W12-140 on the ground floor of the Department of Transportation West Building... on an irregularly-shaped course located between the Governor Thomas Johnson Memorial (SR-4) Bridge..., we do discuss the effects of this rule elsewhere in this preamble. 8. Taking of Private Property This...

Bacteria form tellurium nanocrystals

USGS Publications Warehouse

Oremland, R.S.

2007-01-01

A team of researchers have found two bacterial species that produce tellurium oxyanions as respiratory electron acceptors for growth, leaving elemental tellurium in the form of nanoparticles. The crystals from the two organisms exhibit distinctively different structures. Bacillus selenitireducens initially forms nanorods that cluster together to form rosettes. Sulfurospirillum barnesii forms irregularly-shaped nanospheres that coalesce into larger composite aggregates.

Design of a shape adaptive airfoil actuated by a Shape Memory Alloy strip for airplane tail

NASA Astrophysics Data System (ADS)

Shirzadeh, R.; Raissi Charmacani, K.; Tabesh, M.

2011-04-01

Of the factors that mainly affect the efficiency of the wing during a special flow regime, the shape of its airfoil cross section is the most significant. Airfoils are generally designed for a specific flight condition and, therefore, are not fully optimized in all flight conditions. It is very desirable to have an airfoil with the ability to change its shape based on the current regime. Shape memory alloy (SMA) actuators activate in response to changes in the temperature and can recover their original configuration after being deformed. This study presents the development of a method to control the shape of an airfoil using SMA actuators. To predict the thermomechanical behaviors of an SMA thin strip, 3D incremental formulation of the SMA constitutive model is implemented in FEA software package ABAQUS. The interactions between the airfoil structure and SMA thin strip actuator are investigated. Also, the aerodynamic performance of a standard airfoil with a plain flap is compared with an adaptive airfoil.

A new method for 3D thinning of hybrid shaped porous media using artificial intelligence. Application to trabecular bone.

PubMed

Jennane, Rachid; Aufort, Gabriel; Benhamou, Claude Laurent; Ceylan, Murat; Ozbay, Yüksel; Ucan, Osman Nuri

2012-04-01

Curve and surface thinning are widely-used skeletonization techniques for modeling objects in three dimensions. In the case of disordered porous media analysis, however, neither is really efficient since the internal geometry of the object is usually composed of both rod and plate shapes. This paper presents an alternative to compute a hybrid shape-dependent skeleton and its application to porous media. The resulting skeleton combines 2D surfaces and 1D curves to represent respectively the plate-shaped and rod-shaped parts of the object. For this purpose, a new technique based on neural networks is proposed: cascade combinations of complex wavelet transform (CWT) and complex-valued artificial neural network (CVANN). The ability of the skeleton to characterize hybrid shaped porous media is demonstrated on a trabecular bone sample. Results show that the proposed method achieves high accuracy rates about 99.78%-99.97%. Especially, CWT (2nd level)-CVANN structure converges to optimum results as high accuracy rate-minimum time consumption.

Quantitative analysis of morphological changes in yeast colonies growing on solid medium: the eccentricity and Fourier indices.

PubMed

Gil de Prado, Elena; Rivas, Eva-María; de Silóniz, María-Isabel; Diezma, Belén; Barreiro, Pilar; Peinado, José M

2014-11-01

The colony shape of four yeast species growing on agar medium was measured for 116 days by image analysis. Initially, all the colonies are circular, with regular edges. The loss of circularity can be quantitatively estimated by the eccentricity index, Ei , calculated as the ratio between their orthogonal vertical and horizontal diameters. Ei can increase from 1 (complete circularity) to a maximum of 1.17-1.30, depending on the species. One colony inhibits its neighbour only when it has reached a threshold area. Then, Ei of the inhibited colony increases proportionally to the area of the inhibitory colony. The initial distance between colonies affects those threshold values but not the proportionality, Ei /area; this inhibition affects the shape but not the total surface of the colony. The appearance of irregularities in the edges is associated, in all the species, not with age but with nutrient exhaustion. The edge irregularity can be quantified by the Fourier index, Fi , calculated by the minimum number of Fourier coefficients that are needed to describe the colony contour with 99% fitness. An ad hoc function has been developed in Matlab v. 7.0 to automate the computation of the Fourier coefficients. In young colonies, Fi has a value between 2 (circumference) and 3 (ellipse). These values are maintained in mature colonies of Debaryomyces, but can reach values up to 14 in Saccharomyces. All the species studied showed the inhibition of growth in facing colony edges, but only three species showed edge irregularities associated with substrate exhaustion. Copyright © 2014 John Wiley & Sons, Ltd.

Morphology, ultrastructure, and chemical compounds of the osmeterium of Heraclides thoas (Lepidoptera: Papilionidae).

PubMed

Martínez, Luis Carlos; Plata-Rueda, Angelica; da Silva Neves, Guilherme; Cossolin, Jamile Fernanda; Dos Santos, Marcelo Henrique; Zanuncio, José Cola; Serrão, José Eduardo

2018-05-11

The osmeterium, found in papilionoid larvae, is an eversible organ with an exocrine gland that produces substances in response to the mechanical disturbances caused by natural enemies. The anatomy, histology and ultrastructure of the osmeterium, and the chemical composition of its secretion in Heraclides thoas (Lepidoptera: Papilionidae) were studied. Heraclides thoas larvae have a Y-shaped osmeterium in the thorax. The surface of the osmeterium has a rough cuticle lining cells with papillae and irregular folds, whereas the cells that limited the gland pores are irregular, folded, and devoid of papillae. Two types of cells are found: (i) cuticular epidermal cells on the surface of the tubular arms of the osmeterium and (ii) secretory cells of the ellipsoid gland within the region of the glandular pore. Cuticular epidermal cells show a thick cuticle, with several layers divided into epicuticle and lamellar endocuticle. Secretory cells are polygonal, with extensive folds in the basal plasma membrane that formed extracellular channels. The cytoplasm has mitochondria, ribosomes, and numerous vacuoles, whereas the nucleus is irregular in shape with decondensed chromatin. The chemical composition of the osmeterial secretion comprised (Z)-α-bisabolene (25.4%), α-bisabol (20.6%), β-bisabolene (13.1%), (E)-α-bisabolene 8%), β-pinene (9.91%), longipinene epoxide (8.92%), (Z)-β-farnesene (6.96%), β-caryophyllene (2.05%), farnesol (1.86%), linalyl propionate (1.86%), and 1-octyn-4-ol (1.07%). The morphological features suggest that the cuticular epidermal cells play a major role in the maintenance and protection of the osmeterium, whereas secretory cells are responsible for production of osmeterial secretions.

Multiphonon Raman scattering and photoluminescence studies of CdS nanocrystals grown by thermal evaporation

NASA Astrophysics Data System (ADS)

Farid, Sidra; Stroscio, Michael A.; Dutta, Mitra

2018-03-01

Thermal evaporation growth technique is presented as a route to grow cost effective high quality CdS thin films. We have successfully grown high quality CdS thin films on ITO coated glass substrates by thermal evaporation technique and analyzed the effects of annealing and excitation dependent input of CdS thin film using Raman and photoluminescence spectroscopy. LO phonon modes have been analyzed quantitatively considering the contributions due to anneal induced effects on film quality using phonon spatial correlation model, line shape and defect state analysis. Asymmetry in the Raman line shape towards the low frequency side is related to the phonon confinement effects and is modeled by spatial correlation model. Calculations of width (FWHM), integrated intensity, and line shape for the longitudinal (LO) optical phonon modes indicate improved crystalline quality for the annealed films as compared to the as grown films. With increase in laser power, intensity ratio of 2-LO to 1-LO optical phonon modes is found to increase while multiple overtones upto fourth order are observed. Power dependent photoluminescence data indicates direct band-to-band transition in CdS thin films.

The cytoskeletal system of nucleated erythrocytes. I. Composition and function of major elements

PubMed Central

1982-01-01

We have studied the dogfish erythrocyte cytoskeletal system, which consists of a marginal band of microtubules (MB) and trans-marginal band material (TBM). The TBM appeared in whole mounts as a rough irregular network and in thin sections as a surface-delimiting layer completely enclosing nucleus and MB. In cells incubated at 0 degrees C for 30 min or more, the MB disappeared but the TBM remained. MB reassembly occurred with rewarming, and was inhibited by colchicine. Flattened elliptical erythrocyte morphology was retained even when MBs were absent. Total solubilization of MB and TBM at low pH, or dissolution of whole anucleate cytoskeletons, yielded components comigrating with actin, spectrin, and tubulin standards during gel electrophoresis. Mass-isolated MBs, exhibiting ribbonlike construction apparently maintained by cross-bridges, contained four polypeptides in the tubulin region of the gel. Only these four bands were noticeably increased in the soluble phase obtained from cells with 0 degrees C- disassembled MBs. The best isolated MB preparations contained tubulin but no components comigrating with high molecular weight microtubule- associated proteins, spectrin, or actin. Actin and spectrin therefore appear to be major TBM constituents, with tubulin localized in the MB. The results are interpreted in terms of an actin- and spectrin- containing subsurface cytoskeletal layer (TBM), related to that of mammalian erythrocytes, which maintains cell shape in the absence of MBs. Observations on abnormal pointed erythrocytes containing similarly pointed MBs indicate further that the MB can deform the TBM from within so as to alter cell shape. MBs may function in this manner during normal cellular morphogenesis and during blood flow in vivo. PMID:6889600

Thinning effects on tree mortality and snag recruitment in western Oregon

Treesearch

Erich Kyle Dodson; Klaus J. Puettmann; Adrian Ares

2013-01-01

Tree mortality shapes forest structural development and the resulting dead wood provides habitat for many species. However, the eff ects of thinning on mortality and large snag recruitment have been variable and remain poorly understood. We examined thinning eff ects on tree mortality at eleven Density Management Study (DMS) sites in western Oregon. Th inning reduced...

Thinning method and intensity influence long-term mortality trends in a red pine forest

Treesearch

Matthew D. Powers; Brian J. Palik; John B. Bradford; Shawn Fraver; Christopher R. Webster

2010-01-01

Tree mortality shapes forest development, but rising mortality can represent lost production or an adverse response to changing environmental conditions. Thinning represents a strategy for reducing mortality rates, but different thinning techniques and intensities could have varying impacts depending on how they alter stand structure. We analyzed trends in stand...

Thermal runaway and microwave heating in thin cylindrical domains

NASA Astrophysics Data System (ADS)

Ward, Michael J.

2002-04-01

The behaviour of the solution to two nonlinear heating problems in a thin cylinder of revolution of variable cross-sectional area is analysed using asymptotic and numerical methods. The first problem is to calculate the fold point, corresponding to the onset of thermal runaway, for a steady-state nonlinear elliptic equation that arises in combustion theory. In the limit of thin cylindrical domains, it is shown that the onset of thermal runaway can be delayed when a circular cylindrical domain is perturbed into a dumbell shape. Numerical values for the fold point for different domain shapes are obtained asymptotically and numerically. The second problem that is analysed is a nonlinear parabolic equation modelling the microwave heating of a ceramic cylinder by a known electric field. The basic model in a thin circular cylindrical domain was analysed in Booty & Kriegsmann (Meth. Appl. Anal. 4 (1994) p. 403). Their analysis is extended to treat thin cylindrical domains of variable cross-section. It is shown that the steady-state and dynamic behaviours of localized regions of high temperature, called hot-spots, depend on a competition between the maxima of the electric field and the maximum deformation of the circular cylinder. For a dumbell-shaped region it is shown that two disconnected hot-spot regions can occur. Depending on the parameters in the model, these regions, ultimately, either merge as time increases or else remain as disconnected regions for all time.

Solar granulation and statistical crystallography: A modeling approach using size-shape relations

NASA Technical Reports Server (NTRS)

Noever, D. A.

1994-01-01

The irregular polygonal pattern of solar granulation is analyzed for size-shape relations using statistical crystallography. In contrast to previous work which has assumed perfectly hexagonal patterns for granulation, more realistic accounting of cell (granule) shapes reveals a broader basis for quantitative analysis. Several features emerge as noteworthy: (1) a linear correlation between number of cell-sides and neighboring shapes (called Aboav-Weaire's law); (2) a linear correlation between both average cell area and perimeter and the number of cell-sides (called Lewis's law and a perimeter law, respectively) and (3) a linear correlation between cell area and squared perimeter (called convolution index). This statistical picture of granulation is consistent with a finding of no correlation in cell shapes beyond nearest neighbors. A comparative calculation between existing model predictions taken from luminosity data and the present analysis shows substantial agreements for cell-size distributions. A model for understanding grain lifetimes is proposed which links convective times to cell shape using crystallographic results.

Fingered bola body, bola with same, and methods of use

NASA Technical Reports Server (NTRS)

Dzenitis, John M. (Inventor); Billica, Linda W. (Inventor)

1994-01-01

The present invention discloses bola bodies, bolas, and a snaring method which makes use such devices. A bola body, according to the present invention, is nonspherical or irregular in shape rather than a smooth sphere or ovoid body. One or more fingers extends from the bola body. These fingers may be relatively straight or they may have crooked or bent portions to enhance entanglement with a bola line or lines or with each other. Two or more of such fingers may be used and may be regularly or irregularly spaced apart on a bola body. A bola with such bodies includes lines which are connected to the other bodies. In one particular embodiment of a bola body, according to the present invention, the body has an irregular shape with a bottom rectangular portion and a top pyramid portion forming a nose. A plurality of fingers is extended from the pyramidal top portion with one finger extended up and away from each of four corners of the top portion. Such a bola body tends to be initially oriented with its nose and fingers against an object being snared since the body is pulled nose first when a bola line is secured at the tip of the pyramidal portion of the bola body. With such a bola, an unwrapping bola body can slip around a target member so that two of the rod-shaped fingers catch a bola line and guide it into an area or crook between the fingers and a side of the top pyramidal portion of the bola body. Tension on the bola line maintains the line in the crook and tends to press the fingers against the unwrapped target member to stabilize the wrapping of the line about the target member. With such a bola, it is difficult for two or more lines unwrapping in different directions to move past one another without being forced together by line tension. Also, the fingers of such bola bodies may hook and hold each other. The fingers may also hook or entangle some object on or portion of the target member. A probable known target member has known dimensions and shapes so that the bola may be sized and configured to reliably snare such a known target. The bolas can be optimally sized, fashioned, and configured to contact and hold a probable target of known size, dimension, and shape.

Cell-substrate impedance fluctuations of single amoeboid cells encode cell-shape and adhesion dynamics

NASA Astrophysics Data System (ADS)

Leonhardt, Helmar; Gerhardt, Matthias; Höppner, Nadine; Krüger, Kirsten; Tarantola, Marco; Beta, Carsten

2016-01-01

We show systematic electrical impedance measurements of single motile cells on microelectrodes. Wild-type cells and mutant strains were studied that differ in their cell-substrate adhesion strength. We recorded the projected cell area by time-lapse microscopy and observed irregular oscillations of the cell shape. These oscillations were correlated with long-term variations in the impedance signal. Superposed to these long-term trends, we observed fluctuations in the impedance signal. Their magnitude clearly correlated with the adhesion strength, suggesting that strongly adherent cells display more dynamic cell-substrate interactions.

Simple ectopic kidney in three dogs.

PubMed

Choi, Jiyoung; Lee, Heechun; Lee, Youngwon; Choi, Hojung

2012-10-01

Simple ectopic kidney was diagnosed in three dogs by means of radiography and ultrasonography. A 2-year-old castrated male Schnauzer, a 13-year-old female Schnauzer and a 9-year-old male Jindo were referred with vomiting, hematuria and ocular discharge, respectively. In all three dogs, oval-shaped masses with soft tissue density were observed in the mid to caudal abdomen bilaterally or unilaterally, and kidney silhouettes were not identified at the proper anatomic places on abdominal radiographs. Ultrasonography confirmed the masses were malpositioned kidney. The ectopic kidneys had relatively small size, irregular shape and short ureter but showed normal function on excretory urography.

Influence of substrate micropatterning on biofilm growth

NASA Astrophysics Data System (ADS)

Koehler, Stephan; Li, Yiwei; Liu, Bi-Feng Liu; Weitz, David

2015-11-01

We culture triple reporter Bacillus Subtilis biofilm on micropatterned agar substrates. We track the biofilm development in terms of size, thickness, shape, and phenotype expression. For a tiling composed of elevated rectangles, we observe the biofilm develops an oval shape or triangular shape depending on the rectangle's aspect ratio and orientation. The motile cells are primarily located in the valleys between the rectangles and the matrix producing cells are mostly located on the rectangles. Wrinkles form at the edges of the elevated surfaces, and upon merging form channels centered on the elevated surface. After a few days, the spore-forming cells appear at the periphery. Since biofilms in nature grow on irregular surfaces, our work may provide insight into the complex patterns observed.

Nodal domains of a non-separable problem—the right-angled isosceles triangle

NASA Astrophysics Data System (ADS)

Aronovitch, Amit; Band, Ram; Fajman, David; Gnutzmann, Sven

2012-03-01

We study the nodal set of eigenfunctions of the Laplace operator on the right-angled isosceles triangle. A local analysis of the nodal pattern provides an algorithm for computing the number νn of nodal domains for any eigenfunction. In addition, an exact recursive formula for the number of nodal domains is found to reproduce all existing data. Eventually, we use the recursion formula to analyse a large sequence of nodal counts statistically. Our analysis shows that the distribution of nodal counts for this triangular shape has a much richer structure than the known cases of regular separable shapes or completely irregular shapes. Furthermore, we demonstrate that the nodal count sequence contains information about the periodic orbits of the corresponding classical ray dynamics.

Modified Withdrawal Slot Increases Silicon Production

NASA Technical Reports Server (NTRS)

Piotrowsky, P. A.; Duncan, C. S.

1988-01-01

New shape reduces ribbon breakage and resulting idle time. Shape for slot through which single-crystal silicon ribbon pulled from melt increases productivity. Reduces tendency of emerging ribbon to grow thin and break.

Directed dewetting of amorphous silicon film by a donut-shaped laser pulse.

PubMed

Yoo, Jae-Hyuck; In, Jung Bin; Zheng, Cheng; Sakellari, Ioanna; Raman, Rajesh N; Matthews, Manyalibo J; Elhadj, Selim; Grigoropoulos, Costas P

2015-04-24

Irradiation of a thin film with a beam-shaped laser is proposed to achieve site-selectively controlled dewetting of the film into nanoscale structures. As a proof of concept, the laser-directed dewetting of an amorphous silicon thin film on a glass substrate is demonstrated using a donut-shaped laser beam. Upon irradiation of a single laser pulse, the silicon film melts and dewets on the substrate surface. The irradiation with the donut beam induces an unconventional lateral temperature profile in the film, leading to thermocapillary-induced transport of the molten silicon to the center of the beam spot. Upon solidification, the ultrathin amorphous silicon film is transformed to a crystalline silicon nanodome of increased height. This morphological change enables further dimensional reduction of the nanodome as well as removal of the surrounding film material by isotropic silicon etching. These results suggest that laser-based dewetting of thin films can be an effective way for scalable manufacturing of patterned nanostructures.

Body shape perception and dieting in preadolescent British Asian girls: links with eating disorders.

PubMed

Hill, A J; Bhatti, R

1995-03-01

Body shape dissatisfaction and dieting have previously been reported in 9-year-old Caucasian girls. As British adolescents of Asian origin appear at least as vulnerable to eating disorders, the present study investigated these issues in preadolescent British Asian girls. Fifty-five Asian and 42 Caucasian 9-year-olds completed assessments of dietary restraint, body esteem, body satisfaction, and body figure preferences. The study revealed a high priority for thinness in both the Asian and Caucasian girls. Their desire for thinness was present even though the Asian girls had a significantly lower body weight than their Caucasian peers. Both groups of high restraint girls expressed body shape discontent and lower body esteem. In addition, an association was found in the Asian sample between reported dieting and the cultural orientation of their family. These results demonstrate the wide appeal of thinness, which in combination with intercultural and intrafamilial conflict, may strongly influence eating and contribute to the development of eating disorders.

Two- and three-dimensional folding of thin film single-crystalline silicon for photovoltaic power applications

PubMed Central

Guo, Xiaoying; Li, Huan; Yeop Ahn, Bok; Duoss, Eric B.; Hsia, K. Jimmy; Lewis, Jennifer A.; Nuzzo, Ralph G.

2009-01-01

Fabrication of 3D electronic structures in the micrometer-to-millimeter range is extremely challenging due to the inherently 2D nature of most conventional wafer-based fabrication methods. Self-assembly, and the related method of self-folding of planar patterned membranes, provide a promising means to solve this problem. Here, we investigate self-assembly processes driven by wetting interactions to shape the contour of a functional, nonplanar photovoltaic (PV) device. A mechanics model based on the theory of thin plates is developed to identify the critical conditions for self-folding of different 2D geometrical shapes. This strategy is demonstrated for specifically designed millimeter-scale silicon objects, which are self-assembled into spherical, and other 3D shapes and integrated into fully functional light-trapping PV devices. The resulting 3D devices offer a promising way to efficiently harvest solar energy in thin cells using concentrator microarrays that function without active light tracking systems. PMID:19934059

Influence of Thin-Film Adhesives in Pullout Tests Between Nickel-Titanium Shape Memory Alloy and Carbon Fiber-Reinforced Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Quade, Derek J.; Jana, Sadhan; McCorkle, Linda S.

2018-01-01

Strips of nickel-titanium (NiTi) shape memory alloy (SMA) and carbon fiber-reinforced polymer matrix composite (PMC) were bonded together using multiple thin film adhesives and their mechanical strengths were evaluated under pullout test configuration. Tensile and lap shear tests were conducted to confirm the deformation of SMAs at room temperature and to evaluate the adhesive strength between the NiTi strips and the PMC. Optical and scanning electron microscopy techniques were used to examine the interfacial bonding after failure. Simple equations on composite tensile elongation were used to fit the experimental data on tensile properties. ABAQUS models were generated to show the effects of enhanced bond strength and the distribution of stress in SMA and PMC. The results revealed that the addition of thin film adhesives increased the average adhesive strength between SMA and PMC while halting the room temperature shape memory effect within the pullout specimen.

Two- and three-dimensional folding of thin film single-crystalline silicon for photovoltaic power applications.

PubMed

Guo, Xiaoying; Li, Huan; Ahn, Bok Yeop; Duoss, Eric B; Hsia, K Jimmy; Lewis, Jennifer A; Nuzzo, Ralph G

2009-12-01

Fabrication of 3D electronic structures in the micrometer-to-millimeter range is extremely challenging due to the inherently 2D nature of most conventional wafer-based fabrication methods. Self-assembly, and the related method of self-folding of planar patterned membranes, provide a promising means to solve this problem. Here, we investigate self-assembly processes driven by wetting interactions to shape the contour of a functional, nonplanar photovoltaic (PV) device. A mechanics model based on the theory of thin plates is developed to identify the critical conditions for self-folding of different 2D geometrical shapes. This strategy is demonstrated for specifically designed millimeter-scale silicon objects, which are self-assembled into spherical, and other 3D shapes and integrated into fully functional light-trapping PV devices. The resulting 3D devices offer a promising way to efficiently harvest solar energy in thin cells using concentrator microarrays that function without active light tracking systems.

Modeling and Performance Improvement of the Constant Power Regulator Systems in Variable Displacement Axial Piston Pump

PubMed Central

Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

2013-01-01

An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software. PMID:24282389

Textural defect detect using a revised ant colony clustering algorithm

NASA Astrophysics Data System (ADS)

Zou, Chao; Xiao, Li; Wang, Bingwen

2007-11-01

We propose a totally novel method based on a revised ant colony clustering algorithm (ACCA) to explore the topic of textural defect detection. In this algorithm, our efforts are mainly made on the definition of local irregularity measurement and the implementation of the revised ACCA. The local irregular measurement defined evaluates the local textural inconsistency of each pixel against their mini-environment. In our revised ACCA, the behaviors of each ant are divided into two steps: release pheromone and act. The quantity of pheromone released is proportional to the irregularity measurement; the actions of the ants to act next are chosen independently of each other in a stochastic way according to some evaluated heuristic knowledge. The independency of ants implies the inherent parallel computation architecture of this algorithm. We apply the proposed method in some typical textural images with defects. From the series of pheromone distribution map (PDM), it can be clearly seen that the pheromone distribution approaches the textual defects gradually. By some post-processing, the final distribution of pheromone can demonstrate the shape and area of the defects well.

Fat, friendless and unhealthy: 9-year old children's perception of body shape stereotypes.

PubMed

Hill, A J; Silver, E K

1995-06-01

Society has a very negative view of overweight, leading to prejudice and discrimination. In an examination of the scope of these views, 9-year old children's attributions of the social functioning and health of thin and overweight body shapes were investigated. One hundred and eighty eight girls and boys completed a series of ratings of four silhouette figures depicting a thin and heavy boy and girl. The children's own body shape preference, dietary restraint, height and weight were also measured. The ratings of the four silhouette variations were dominated by the size of the figure being judged. The overweight body shape was associated with poor social functioning, impaired academic success, and low perceived health, healthy eating and fitness. Gender and the raters own body weight had only limited impact on these stereotypical judgements. Children's judgements of themselves on the same attributes showed a greater perceived relevance of weight for girls and a confusion of healthy eating with dieting. Pre-adolescent children's perception of thinness and overweight echo the prejudices against overweight voiced by society. Health promotion at all ages will require a more considered presentation of the health implications of overweight.

The onset of spiral structure in the universe

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

Elmegreen, Debra Meloy; Elmegreen, Bruce G.

2014-01-20

The onset of spiral structure in galaxies appears to occur between redshifts 1.4 and 1.8 when disks have developed a cool stellar component, rotation dominates over turbulent motions in the gas, and massive clumps become less frequent. During the transition from clumpy to spiral disks, two unusual types of spirals are found in the Hubble Ultra Deep Field that are massive, clumpy, and irregular like their predecessor clumpy disks, yet spiral-like or sheared like their descendants. One type is 'woolly' with massive clumpy arms all over the disk and is brighter than other disk galaxies at the same redshift, whilemore » another type has irregular multiple arms with high pitch angles, star formation knots, and no inner symmetry like today's multiple-arm galaxies. The common types of spirals seen locally are also present in a redshift range around z ∼ 1, namely grand design with two symmetric arms, multiple arm with symmetry in the inner parts and several long, thin arms in the outer parts, and flocculent, with short, irregular, and patchy arms that are mostly from star formation. Normal multiple-arm galaxies are found only closer than z ∼ 0.6 in the Ultra Deep Field. Grand design galaxies extend furthest to z ∼ 1.8, presumably because interactions can drive a two-arm spiral in a disk that would otherwise have a more irregular structure. The difference between these types is understandable in terms of the usual stability parameters for gas and stars, and the ratio of the velocity dispersion to rotation speed.« less

Handle-shaped Prominence

NASA Image and Video Library

2001-02-17

NASA Extreme Ultraviolet Imaging Telescope aboard ESA’s SOHO spacecraft took this image of a huge, handle-shaped prominence in 1999. Prominences are huge clouds of relatively cool dense plasma suspended in the Sun hot, thin corona.

Geometrical shape design of nanophotonic surfaces for thin film solar cells.

PubMed

Nam, W I; Yoo, Y J; Song, Y M

2016-07-11

We present the effect of geometrical parameters, particularly shape, on optical absorption enhancement for thin film solar cells based on crystalline silicon (c-Si) and gallium arsenide (GaAs) using a rigorous coupled wave analysis (RCWA) method. It is discovered that the "sweet spot" that maximizes efficiency of solar cells exists for the design of nanophotonic surfaces. For the case of ultrathin, rod array is practical due to the effective optical resonances resulted from the optimum geometry whereas parabola array is viable for relatively thicker cells owing to the effective graded index profile. A specific value of thickness, which is the median value of other two devices tailored by rod and paraboloid, is optimized by truncated shape structure. It is therefore worth scanning the optimum shape of nanostructures in a given thickness in order to achieve high performance.

My Experience with Ti-Ni-Based and Ti-Based Shape Memory Alloys

NASA Astrophysics Data System (ADS)

Miyazaki, Shuichi

2017-12-01

The present author has been studying shape memory alloys including Cu-Al-Ni, Ti-Ni-based, and Ni-free Ti-based alloys since 1979. This paper reviews the present author's research results for the latter two materials since 1981. The topics on the Ti-Ni-based alloys include the achievement of superelasticity in Ti-Ni alloys through understanding of the role of microstructures consisting of dislocations and precipitates, followed by the contribution to the development of application market of shape memory effect and superelasticity, characterization of the R-phase and monoclinic martensitic transformations, clarification of the basic characteristics of fatigue properties, development of sputter-deposited shape memory thin films and fabrication of prototypes of microactuators utilizing thin films, development of high temperature shape memory alloys, and so on. The topics of Ni-free Ti-based shape memory alloys include the characterization of the orthorhombic phase martensitic transformation and related shape memory effect and superelasticity, the effects of texture, omega phase and adding elements on the martensitic transformation and shape memory properties, clarification of the unique effects of oxygen addition to induce non-linear large elasticity, Invar effect and heating-induced martensitic transformation, and so on.

Can we apply the MRI BI-RADS lexicon morphology descriptors on contrast-enhanced spectral mammography?

PubMed Central

Kamal, Rasha M; Helal, Maha H; Haggag, Marwa A; Nada, Omniya M; Farahat, Iman G; Alieldin, Nelly H

2016-01-01

Objective: To assess the feasibility of using the MRI breast imaging reporting and data system (BI-RADS) lexicon morphology descriptors to characterize enhancing breast lesions identified on contrast-enhanced spectral mammography (CESM). Methods: The study is a retrospective analysis of the morphology descriptors of 261 enhancing breast lesions identified on CESM in 239 patients. We presented the morphological categorization of the included lesions into focus, mass and non-mass. Further classifications included (1) the multiplicity for “focus” category, (2) the shape, margin and internal enhancement for “mass” category and (3) the distribution and internal enhancement for “non-mass” category. Each morphology descriptor was evaluated individually (irrespective of all other descriptors) by calculating its sensitivity, specificity, positive-predictive value (PPV) and negative-predictive value (NPV) and likelihood ratios (LRs). Results: The study included 68/261 (26.1%) benign lesions and 193/261 (73.9%) malignant lesions. Intensely enhancing foci, whether single (7/12, 58.3%) or multiple (2/12, 16.7%), were malignant. Descriptors of “irregular”-shape (PPV: 92.4%) and “non-circumscribed” margin (odds ratio: 55.2, LR positive: 4.77; p-value: <0.001) were more compatible with malignancy. Internal mass enhancement patterns showed a very low specificity (58.0%) and NPV (40.0%). Non-mass enhancement (NME) was detected in 81/261 lesions. Asymmetrical NME in 81% (n = 52/81) lesions was malignant lesions and internal enhancement patterns indicative of malignancy were the heterogeneous and clumped ones. Conclusion: We can apply the MRI morphology descriptors to characterize lesions on CESM, but with few expectations. In many situations, irregular-shaped, non-circumscribed masses and NME with focal, ductal or segmental distribution and heterogeneous or clumped enhancement are the most suggestive descriptors of malignant pathologies. Advances in knowledge: (1) The MRI BI-RADS lexicon morphology descriptors can be applied in the characterization of enhancing lesions on CESM with a few exceptions. (2) Multiple bilateral intensely enhancing foci should not be included under the normal background parenchymal enhancement unless they are proved to be benign by biopsy. (3) Mass lesion features that indicated malignancy were irregular-shaped, spiculated and irregular margins and heterogeneous internal enhancement patterns. The rim enhancement pattern should not be considered as a descriptor of malignant lesions unless CESM is coupled with an ultrasound examination. PMID:27327403

Greenstone belts: Their components and structure

NASA Technical Reports Server (NTRS)

Vearncombe, J. R.; Barton, J. M., Jr.; Vanreenen, D. D.; Phillips, G. N.; Wilson, A. H.

1986-01-01

Greenstone sucessions are defined as the nongranitoid component of granitoid-greenstone terrain and are linear to irregular in shape and where linear are termed belts. The chemical composition of greenstones is described. Also discussed are the continental environments of greenstone successions. The effects of contact with granitoids, geophysical properties, recumbent folds and late formation structures upon greenstones are examined. Large stratigraphy thicknesses are explained.

The gravitational potential of a homogeneous polyhedron or don't cut corners

NASA Technical Reports Server (NTRS)

Werner, Robert A.

1994-01-01

A polyhedron can model irregularly shaped objects such as asteroids, comet nuclei, and small planetary satellites. With minor effort, such a model can incorporate important surface features such as large craters. Here we develop closed-form expressions for the exterior gravitational potential and acceleration components due to a constant-density polyhedron. An equipotential surface of Phobos is illustrated.

Affirming Irregular Spaces in a School-Wide Curriculum Initiative: A Place for the Animals

ERIC Educational Resources Information Center

Lynch, Julianne; Herbert, Sandra

2015-01-01

School-wide curriculum initiatives are complex fields of activity, held together by a cast of heterogeneous actors who put diverse discourses to work in their everyday efforts to shape their work. This paper draws upon qualitative data collected across an 18-month period in a regional Australian primary school that, since the beginning of 2012,…

Structure, photoluminescence and thermoluminescence study of a composite ZnTa2O6/ZnGa2O4 compound doped with Pr3+

NASA Astrophysics Data System (ADS)

Noto, L. L.; Shaat, S. K. K.; Poelman, D.; Dhlamini, M. S.; Mothudi, B. M.; Swart, H. C.

2016-05-01

The study of persistent luminescence is interesting for applications related to biological imaging, self-lit roads and security signs. Composite Pr-doped samples were prepared in one pot by solid chemical reaction at 1200 °C for 4 h. The X-ray diffraction patterns of the samples showed mixed phases which correspond to ZnGa2O4 and ZnTa2O6 phases. Interestingly, the secondary electron microscopy images showed that the surface morphology is composed of particles with different shapes: irregular, rhombus and rod shapes. The X-ray maps obtained using field emission scanning electron microscopy, confirmed that the irregular particles correspond to ZnTa2O6, and the rods correspond to ZnGa2O4. Red emission was observed from 1D2 → 3H4, 3P0 → 3H6, 3P0 → 3F2 and 1D2 → 3H5 transitions of Pr3+. The lifetime of the persistent luminescence was measured, and the corresponding trapping centres were investigated using thermoluminescence spectroscopy.

Agglomerates, smoke oxide particles, and carbon inclusions in condensed combustion products of an aluminized GAP-based propellant

NASA Astrophysics Data System (ADS)

Ao, Wen; Liu, Peijin; Yang, Wenjing

2016-12-01

In solid propellants, aluminum is widely used to improve the performance, however the condensed combustion products especially the large agglomerates generated from aluminum combustion significantly affect the combustion and internal flow inside the solid rocket motor. To clarify the properties of the condensed combustion products of aluminized propellants, a constant-pressure quench vessel was adopted to collect the combustion products. The morphology and chemical compositions of the collected products, were then studied by using scanning electron microscopy coupled with energy dispersive (SEM-EDS) method. Various structures have been observed in the condensed combustion products. Apart from the typical agglomerates or smoke oxide particles observed before, new structures including the smoke oxide clusters, irregular agglomerates and carbon-inclusions are discovered and investigated. Smoke oxide particles have the highest amount in the products. The highly dispersed oxide particle is spherical with very smooth surface and is on the order of 1-2 μm, but due to the high temperature and long residence time, these small particles will aggregate into smoke oxide clusters which are much larger than the initial particles. Three types of spherical agglomerates have been found. As the ambient gas temperature is much higher than the boiling point of Al2O3, the condensation layer inside which the aluminum drop is burning would evaporate quickly, which result in the fact that few "hollow agglomerates" has been found compared to "cap agglomerates" and "solid agglomerates". Irregular agglomerates usually larger than spherical agglomerates. The formation of irregular agglomerates likely happens by three stages: deformation of spherical aluminum drops; combination of particles with various shape; finally production of irregular agglomerates. EDS results show the ratio of O to Al on the surface of agglomerates is lower in comparison to smoke oxide particles. C and O account for most element compositions for all the carbon inclusions. The rough, spherical, strip shape and flake shape carbon-inclusions are believed to be derived from the degradation products of the binder or oxidizer, while the fiber silk is possibly the combustion product of fiber inside the heat insulation layer of the propellants. Images of products at different pressures reveal high pressure reduces the degree of agglomeration. The chemical compositions, size range and content of all the observed structures are given in this paper. Results of our study are expected to provide better insight in the working process of solid rocket motor.

Identification and Characterization of Pseudocercospora pyricola Causing Leaf Spots on Aronia melanocarpa

PubMed Central

Park, Sung-Hee; Choi, In-Young; Seo, Kyoung-Won; Kim, Jin-Ho; Galea, Victor

2017-01-01

Leaf spot disease on black chokeberry (Aronia melanocarpa) was observed at several locations in Korea during 2014–2015. Leaf spots were distinct, scattered over the leaf surface and along the leaf border, subcircular to irregular and brown surrounded by a distinct dark color, and were expanded and coalesced into irregularly shaped lesions. Severely infected leaves became dry and fell off eventually. The causative agent was identified as Pseudocercospora pyricola. Morphological observations and phylogenetic analyses of multiple genes, including internal transcribed spacer, translation elongation factor 1-alpha, actin, and the large subunit ribosomal DNA were conducted. The pathogenicity test was conducted twice yielding similar results, fulfilling Koch's postulates. To our knowledge, this is the first report on P. pyricola infection of A. melanocarpa globally. PMID:28435353

Micro pulling down growth of very thin shape memory alloys single crystals

NASA Astrophysics Data System (ADS)

López-Ferreño, I.; Juan, J. San; Breczewski, T.; López, G. A.; Nó, M. L.

Shape memory alloys (SMAs) have attracted much attention in the last decades due to their thermo-mechanical properties such as superelasticity and shape memory effect. Among the different families of SMAs, Cu-Al-Ni alloys exhibit these properties in a wide range of temperatures including the temperature range of 100-200∘C, where there is a technological demand of these functional materials, and exhibit excellent behavior at small scale making them more competitive for applications in Micro Electro-Mechanical Systems (MEMS). However, polycrystalline alloys of Cu-based SMAs are very brittle so that they show their best thermo-mechanical properties in single-crystal state. Nowadays, conventional Bridgman and Czochralski methods are being applied to elaborate single-crystal rods up to a minimum diameter of 1mm, but no works have been reported for smaller diameters. With the aim of synthesizing very thin single-crystals, the Micro-Pulling Down (μ-PD) technique has been applied, for which the capillarity and surface tension between crucible and the melt play a critical role. The μ-PD method has been successfully applied to elaborate several cylindrical shape thin single-crystals down to 200μm in diameter. Finally, the martensitic transformation, which is responsible for the shape memory properties of these alloys, has been characterized for different single-crystals. The experimental results evidence the good quality of the grown single-crystals.

A novel method of the image processing on irregular triangular meshes

NASA Astrophysics Data System (ADS)

Vishnyakov, Sergey; Pekhterev, Vitaliy; Sokolova, Elizaveta

2018-04-01

The paper describes a novel method of the image processing based on irregular triangular meshes implementation. The triangular mesh is adaptive to the image content, least mean square linear approximation is proposed for the basic interpolation within the triangle. It is proposed to use triangular numbers to simplify using of the local (barycentric) coordinates for the further analysis - triangular element of the initial irregular mesh is to be represented through the set of the four equilateral triangles. This allows to use fast and simple pixels indexing in local coordinates, e.g. "for" or "while" loops for access to the pixels. Moreover, representation proposed allows to use discrete cosine transform of the simple "rectangular" symmetric form without additional pixels reordering (as it is used for shape-adaptive DCT forms). Furthermore, this approach leads to the simple form of the wavelet transform on triangular mesh. The results of the method application are presented. It is shown that advantage of the method proposed is a combination of the flexibility of the image-adaptive irregular meshes with the simple form of the pixel indexing in local triangular coordinates and the using of the common forms of the discrete transforms for triangular meshes. Method described is proposed for the image compression, pattern recognition, image quality improvement, image search and indexing. It also may be used as a part of video coding (intra-frame or inter-frame coding, motion detection).

Validation of a Novel Technique and Evaluation of the Surface Free Energy of Food

PubMed Central

Senturk Parreidt, Tugce; Schmid, Markus; Hauser, Carolin

2017-01-01

Characterizing the physical properties of a surface is largely dependent on determining the contact angle exhibited by a liquid. Contact angles on the surfaces of rough and irregularly-shaped food samples are difficult to measure using a contact angle meter (goniometer). As a consequence, values for the surface energy and its components can be mismeasured. The aim of this work was to use a novel contact angle measurement method, namely the snake-based ImageJ program, to accurately measure the contact angles of rough and irregular shapes, such as food samples, and so enable more accurate calculation of the surface energy of food materials. In order to validate the novel technique, the contact angles of three different test liquids on four different smooth polymer films were measured using both the ImageJ software with the DropSnake plugin and the widely used contact angle meter. The distributions of the values obtained by the two methods were different. Therefore, the contact angles, surface energies, and polar and dispersive components of plastic films obtained using the ImageJ program and the Drop Shape Analyzer (DSA) were interpreted with the help of simple linear regression analysis. As case studies, the superficial characteristics of strawberry and endive salad epicarp were measured with the ImageJ program and the results were interpreted with the Drop Shape Analyzer equivalent according to our regression models. The data indicated that the ImageJ program can be successfully used for contact angle determination of rough and strongly hydrophobic surfaces, such as strawberry epicarp. However, for the special geometry of droplets on slightly hydrophobic surfaces, such as salad leaves, the program code interpolation part can be altered. PMID:28425932

An efficient algorithm for global periodic orbits generation near irregular-shaped asteroids

NASA Astrophysics Data System (ADS)

Shang, Haibin; Wu, Xiaoyu; Ren, Yuan; Shan, Jinjun

2017-07-01

Periodic orbits (POs) play an important role in understanding dynamical behaviors around natural celestial bodies. In this study, an efficient algorithm was presented to generate the global POs around irregular-shaped uniformly rotating asteroids. The algorithm was performed in three steps, namely global search, local refinement, and model continuation. First, a mascon model with a low number of particles and optimized mass distribution was constructed to remodel the exterior gravitational potential of the asteroid. Using this model, a multi-start differential evolution enhanced with a deflection strategy with strong global exploration and bypassing abilities was adopted. This algorithm can be regarded as a search engine to find multiple globally optimal regions in which potential POs were located. This was followed by applying a differential correction to locally refine global search solutions and generate the accurate POs in the mascon model in which an analytical Jacobian matrix was derived to improve convergence. Finally, the concept of numerical model continuation was introduced and used to convert the POs from the mascon model into a high-fidelity polyhedron model by sequentially correcting the initial states. The efficiency of the proposed algorithm was substantiated by computing the global POs around an elongated shoe-shaped asteroid 433 Eros. Various global POs with different topological structures in the configuration space were successfully located. Specifically, the proposed algorithm was generic and could be conveniently extended to explore periodic motions in other gravitational systems.

Morphologically controlled synthesis of ferric oxide nano/micro particles and their catalytic application in dry and wet media: a new approach.

PubMed

Janjua, Muhammad Ramzan Saeed Ashraf; Jamil, Saba; Jahan, Nazish; Khan, Shanza Rauf; Mirza, Saima

2017-05-31

Morphologically controlled synthesis of ferric oxide nano/micro particles has been carried out by using solvothermal route. Structural characterization displays that the predominant morphologies are porous hollow spheres, microspheres, micro rectangular platelets, octahedral and irregular shaped particles. It is also observed that solvent has significant effect on morphology such as shape and size of the particles. All the morphologies obtained by using different solvents are nearly uniform with narrow size distribution range. The values of full width at half maxima (FWHM) of all the products were calculated to compare their size distribution. The FWHM value varies with size of the particles for example small size particles show polydispersity whereas large size particles have shown monodispersity. The size of particles increases with decrease in polarity of the solvent whereas their shape changes from spherical to rectangular/irregular with decrease in polarity of the solvent. The catalytic activities of all the products were investigated for both dry and wet processes such as thermal decomposition of ammonium per chlorate (AP) and reduction of 4-nitrophenol in aqueous media. The results indicate that each product has a tendency to act as a catalyst. The porous hollow spheres decrease the thermal decomposition temperature of AP by 140 °C and octahedral Fe 3 O 4 particles decrease the decomposition temperature by 30 °C. The value of apparent rate constant (k app ) of reduction of 4-NP has also been calculated.

A Novel Method of Aircraft Detection Based on High-Resolution Panchromatic Optical Remote Sensing Images

PubMed Central

Wang, Wensheng; Nie, Ting; Fu, Tianjiao; Ren, Jianyue; Jin, Longxu

2017-01-01

In target detection of optical remote sensing images, two main obstacles for aircraft target detection are how to extract the candidates in complex gray-scale-multi background and how to confirm the targets in case the target shapes are deformed, irregular or asymmetric, such as that caused by natural conditions (low signal-to-noise ratio, illumination condition or swaying photographing) and occlusion by surrounding objects (boarding bridge, equipment). To solve these issues, an improved active contours algorithm, namely region-scalable fitting energy based threshold (TRSF), and a corner-convex hull based segmentation algorithm (CCHS) are proposed in this paper. Firstly, the maximal variance between-cluster algorithm (Otsu’s algorithm) and region-scalable fitting energy (RSF) algorithm are combined to solve the difficulty of targets extraction in complex and gray-scale-multi backgrounds. Secondly, based on inherent shapes and prominent corners, aircrafts are divided into five fragments by utilizing convex hulls and Harris corner points. Furthermore, a series of new structure features, which describe the proportion of targets part in the fragment to the whole fragment and the proportion of fragment to the whole hull, are identified to judge whether the targets are true or not. Experimental results show that TRSF algorithm could improve extraction accuracy in complex background, and that it is faster than some traditional active contours algorithms. The CCHS is effective to suppress the detection difficulties caused by the irregular shape. PMID:28481260

Ultrastructure of identified fast excitatory, slow excitatory and inhibitory neuromuscular junctions in the locust.

PubMed

Titmus, M J

1981-06-01

The specialized jumping muscle of the locust, the metathoracic extensor tibiae (ETi), is innervated by four physiologically different motoneurons, including FETi, a phasic excitor, SETi, a tonic excitor, and CI, a tonic common inhibitor. FETi neuromuscular junctions were examined in three phasic ETi bundles innervated by FETi. FETi terminals were characterized by patchy contacts on to granular sarcoplasm. The ETi accessory extensor, innervated by both SETi and CI, contains two morphologically different types of axon ending. When this muscle was soaked in horseradish peroxidase, stimulation of SETi led to selective uptake in vesicles in terminals similar to those of FETi axons but containing smaller vesicles, while stimulation by CI caused increased uptake into terminals with more extensive contact directly on to fibrillar sarcoplasm. As has been observed in excitatory and inhibitory synapses in some crustacean and vertebrate nervous systems, the synaptic vesicles in the locust excitatory endings are round and electron-lucent while those in the inhibitory endings are more irregular in shape. The tonic neuromuscular junctions, SETi and CI, are more densely packed with vesicles, larger in cross-sectional area and appear to be of more complex shape than the smaller, vesicle-sparse, phasic FETi terminals. Following long duration stimulation at 10 Hz, the tonic neuromuscular junctions showed little morphological change. FETi endings, which fatigue within minutes at the same stimulation frequency, showed a 20% decrease in synaptic vesicle density and an increase in irregularly shaped membrane inclusions.

Multiple Coulomb scattering in thin silicon

NASA Astrophysics Data System (ADS)

Berger, N.; Buniatyan, A.; Eckert, P.; Förster, F.; Gredig, R.; Kovalenko, O.; Kiehn, M.; Philipp, R.; Schöning, A.; Wiedner, D.

2014-07-01

We present a measurement of multiple Coulomb scattering of 1 to 6 GeV/c electrons in thin (50-140 μm) silicon targets. The data were obtained with the EUDET telescope Aconite at DESY and are compared to parametrisations as used in the Geant4 software package. We find good agreement between data and simulation in the scattering distribution width but large deviations in the shape of the distribution. In order to achieve a better description of the shape, a new scattering model based on a Student's t distribution is developed and compared to the data.

Fabrication of silicon-based shape memory alloy micro-actuators

NASA Technical Reports Server (NTRS)

Johnson, A. David; Busch, John D.; Ray, Curtis A.; Sloan, Charles L.

1992-01-01

Thin film shape memory alloy has been integrated with silicon in a new actuation mechanism for microelectromechanical systems. This paper compares nickel-titanium film with other actuators, describes recent results of chemical milling processes developed to fabricate shape memory alloy microactuators in silicon, and describes simple actuation mechanisms which have been fabricated and tested.

Mammographic mass classification based on possibility theory

NASA Astrophysics Data System (ADS)

Hmida, Marwa; Hamrouni, Kamel; Solaiman, Basel; Boussetta, Sana

2017-03-01

Shape and margin features are very important for differentiating between benign and malignant masses in mammographic images. In fact, benign masses are usually round and oval and have smooth contours. However, malignant tumors have generally irregular shape and appear lobulated or speculated in margins. This knowledge suffers from imprecision and ambiguity. Therefore, this paper deals with the problem of mass classification by using shape and margin features while taking into account the uncertainty linked to the degree of truth of the available information and the imprecision related to its content. Thus, in this work, we proposed a novel mass classification approach which provides a possibility based representation of the extracted shape features and builds a possibility knowledge basis in order to evaluate the possibility degree of malignancy and benignity for each mass. For experimentation, the MIAS database was used and the classification results show the great performance of our approach in spite of using simple features.

Phase-field modeling of two-dimensional crystal growth with anisotropic diffusion.

PubMed

Meca, Esteban; Shenoy, Vivek B; Lowengrub, John

2013-11-01

In the present article, we introduce a phase-field model for thin-film growth with anisotropic step energy, attachment kinetics, and diffusion, with second-order (thin-interface) corrections. We are mainly interested in the limit in which kinetic anisotropy dominates, and hence we study how the expected shape of a crystallite, which in the long-time limit is the kinetic Wulff shape, is modified by anisotropic diffusion. We present results that prove that anisotropic diffusion plays an important, counterintuitive role in the evolving crystal shape, and we add second-order corrections to the model that provide a significant increase in accuracy for small supersaturations. We also study the effect of different crystal symmetries and discuss the influence of the deposition rate.

Method of forming a thin unbacked metal foil

DOEpatents

Duchane, David V.; Barthell, Barry L.

1984-01-01

In a method of forming a thin (<2 .mu.m) unbacked metal foil having a desired curviplanar shape, a soluble polymeric film, preferably comprising polyvinyl alcohol, is formed on a supporting structure having a shape that defines the desired shape of the foil product. A layer of metal foil is deposited onto one side of the soluble film, preferably by vacuum vapor deposition. The metallized film is then immersed in a suitable solvent to dissolve the film and thereby leave the metal foil as an unbacked metal foil element mounted on the supporting structure. Aluminum foils less than 0.2 .mu.m (2,000 .ANG.) thick and having an areal density of less than 54 .mu.g/cm.sup.2 have been obtained.

Thin film bismuth iron oxides useful for piezoelectric devices

DOEpatents

Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

2016-05-31

The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

Fabrication de couches minces a memoire de forme et effets de l'irradiation ionique

NASA Astrophysics Data System (ADS)

Goldberg, Florent

1998-09-01

Nickel and titanium when combined in the right stoichiometric proportion (1:1) can form alloys showing the shape memory effect. Within the scope of this thesis, thin films of such alloys have been successfully produced by sputtering. Precise control of composition is crucial in order to obtain the shape memory effect. A combination of analytical tools which can accurately determine the behavior of such materials is also required (calorimetric analysis, crystallography, composition analysis, etc.). Rutherford backscattering spectrometry has been used for quantitative composition analysis. Thereafter irradiation of films with light ions (He+) of few MeV was shown to allow lowering of the characteristic premartensitic transformation temperatures while preserving the shape memory effect. Those results open the door to a new field of research, particularly for ion irradiation and its potential use as a tool to modify the thermomechanical behavior of shape memory thin film actuators.

Radio Aurora Explorer : Mission overview and the science objectives

NASA Astrophysics Data System (ADS)

Bahcivan, H.; Cutler, J.; Buonocore, J.; Bennett, M.

2009-12-01

Radio Aurora Explorer (RAX) is the first CubeSat mission funded by the NSF Small Satellite Program as a collaborative research of SRI International and the University of Michigan. The mission is a ground-to-space bi-static radar experiment enabling exploration of small-scale turbulent ionospheric structures in the high latitudes not accessible from the ground or space alone. The primary science objective is to understand the microphysics of plasma instabilities that lead to meter-scale plasma turbulence in the form of field-aligned irregularities of electron density between the altitudes of 80 and 400 km. The best-known radar target for the mission is the Farley-Buneman (two-stream) instability occurring in the ionospheric E region when the convection electric field exceeds a threshold of ~20 mV/m. Other targets include spiky structures associated with electrostatic ion cyclotron waves, Post-Rosenbluth, lower, and upper hybrid waves. The science objectives are (1) to determine the altitude distribution of high-latitude ionospheric irregularities as a function of the convection electric field magnitude and direction, (2) to identify the plasma waves responsible for the scattering, and (3) to determine to what extent the irregularities are field-aligned? The mission will measure for the first time the 3-D k-spectrum of the irregularities, in particular measuring their magnetic field alignment. The irregularities will be irradiated by an incoherent scatter radar (PFISR for the first experiments) and the scattered radiation will form a hallow cone-shaped radio aurora into space as illustrated in the figure below. The satellite radar receiver will the scattered signals as the satellite passes through the radio aurora. Irregularity locations will be determined using the time delay between ISR transmissions and satellite receptions. Experiments throughout the lifetime of the mission will determine irregularity intensities as a function altitude, magnetic aspect angle, and as a function of plasma parameters such as convection electric field, plasma density, and temperatures, which are measured effectively simultaneously by the ISR. In this regard, the mission is a well-controlled plasma experiment in a wall-less laboratory.

3D tomography of midlatitude sporadic-E in Japan from GNSS-TEC data

NASA Astrophysics Data System (ADS)

Muafiry, Ihsan Naufal; Heki, Kosuke; Maeda, Jun

2018-03-01

We studied ionospheric irregularities caused by midlatitude sporadic-E ( Es) in Japan using ionospheric total electron content (TEC) data from a dense GNSS array, GEONET, with a 3D (three-dimensional) tomography technique. Es is a thin layer of unusually high ionization that appears at altitudes of 100 km. Here, we studied five cases of Es irregularities in 2010 and 2012, also reported in previous studies, over the Kanto and Kyushu Districts. We used slant TEC residuals as the input and estimated the number of electron density anomalies of more than 2000 small blocks with dimensions of 20-30 km covering a horizontal region of 300 × 500 km. We applied a continuity constraint to stabilize the solution and performed several different resolution tests with synthetic data to assess the accuracy of the results. The tomography results showed that positive electron density anomalies occurred at the E region height, and the morphology and dynamics were consistent with those reported by earlier studies.

Modeling of DNA-Mediated Self-Assembly from Anisotropic Nanoparticles: A Molecular Dynamics Study

NASA Astrophysics Data System (ADS)

Millan, Jaime; Girard, Martin; Brodin, Jeffrey; O'Brien, Matt; Mirkin, Chad; Olvera de La Cruz, Monica

The programmable selectivity of DNA recognition constitutes an elegant scheme to self-assemble a rich variety of superlattices from versatile nanoscale building blocks, where the natural interactions between building blocks are traded by complementary DNA hybridization interactions. Recently, we introduced and validated a scale-accurate coarse-grained model for a molecular dynamics approach that captures the dynamic nature of DNA hybridization events and reproduces the experimentally-observed crystallization behavior of various mixtures of spherical DNA-modified nanoparticles. Here, we have extended this model to robustly reproduce the assembly of nanoparticles with the anisotropic shapes observed experimentally. In particular, we are interested in two different particle types: (i) regular shapes, namely the cubic and octahedral polyhedra shapes commonly observed in gold nanoparticles, and (ii) irregular shapes akin to those exhibited by enzymes. Anisotropy in shape can provide an analog to the atomic orbitals exhibited by conventional atomic crystals. We present results for the assembly of enzymes or anisotropic nanoparticles and the co-assembly of enzymes and nanoparticles.

Path integration guided with a quality map for shape reconstruction in the fringe reflection technique

NASA Astrophysics Data System (ADS)

Jing, Xiaoli; Cheng, Haobo; Wen, Yongfu

2018-04-01

A new local integration algorithm called quality map path integration (QMPI) is reported for shape reconstruction in the fringe reflection technique. A quality map is proposed to evaluate the quality of gradient data locally, and functions as a guideline for the integrated path. The presented method can be employed in wavefront estimation from its slopes over the general shaped surface with slope noise equivalent to that in practical measurements. Moreover, QMPI is much better at handling the slope data with local noise, which may be caused by the irregular shapes of the surface under test. The performance of QMPI is discussed by simulations and experiment. It is shown that QMPI not only improves the accuracy of local integration, but can also be easily implemented with no iteration compared to Southwell zonal reconstruction (SZR). From an engineering point-of-view, the proposed method may also provide an efficient and stable approach for different shapes with high-precise demand.

Improvement of diagnostic efficiency in distinguishing the benign and malignant thyroid nodules via conventional ultrasound combined with ultrasound contrast and elastography

PubMed Central

Liu, Mei-Juan; Men, Yan-Ming; Zhang, Yong-Lin; Zhang, Yu-Xi; Liu, Hao

2017-01-01

We aimed to evaluate the diagnostic values of conventional ultrasound (US), ultrasound contrast (UC) and ultrasound elastography (UE) in distinguishing the benign and malignant thyroid nodules. A total of 100 patients with thyroid nodules receiving operative treatment were selected; they underwent the conventional US, UE and UC examinations before operation, respectively. The nodules received pathological examination after operation to distinguish benign from malignant lesions. The sensitivity, specificity and diagnostic accordance rate of each diagnostic method was evaluated by receiver operating characteristic (ROC) curve, and the area under the curve (AUC) of ROC was calculated. The manifestations of malignant thyroid nodules in conventional US examination were mostly the hypoecho, heterogeneous echo, irregular shape, unclear boundary, aspect ratio <1, microcalcification and irregular peripheral echo halo, and there were statistically significant differences compared with the benign nodules (P<0.05). UE showed that the differences between benign and malignant nodules in 2, 3 and 4 points were statistically significant (P<0.05). The manifestations of malignant nodules in UC were mostly the irregular shape, obscure boundary, no obvious enhancement, heterogeneous enhancement and visible perfusion defects, and there were statistically significant differences compared with the benign nodules (P<0.05). ROC curve showed that both sensitivity and specificity of UE and UC were superior to those of conventional US. AUC was the largest (AUC = 0.908) and the diagnostic value was the highest in the conventional US combined with UE and UC. Conventional US combined with elastography and UC can significantly improve the sensitivity, specificity and accuracy of diagnosis of benign and malignant thyroid nodules. PMID:28693244

Improvement of diagnostic efficiency in distinguishing the benign and malignant thyroid nodules via conventional ultrasound combined with ultrasound contrast and elastography.

PubMed

Liu, Mei-Juan; Men, Yan-Ming; Zhang, Yong-Lin; Zhang, Yu-Xi; Liu, Hao

2017-07-01

We aimed to evaluate the diagnostic values of conventional ultrasound (US), ultrasound contrast (UC) and ultrasound elastography (UE) in distinguishing the benign and malignant thyroid nodules. A total of 100 patients with thyroid nodules receiving operative treatment were selected; they underwent the conventional US, UE and UC examinations before operation, respectively. The nodules received pathological examination after operation to distinguish benign from malignant lesions. The sensitivity, specificity and diagnostic accordance rate of each diagnostic method was evaluated by receiver operating characteristic (ROC) curve, and the area under the curve (AUC) of ROC was calculated. The manifestations of malignant thyroid nodules in conventional US examination were mostly the hypoecho, heterogeneous echo, irregular shape, unclear boundary, aspect ratio <1, microcalcification and irregular peripheral echo halo, and there were statistically significant differences compared with the benign nodules (P<0.05). UE showed that the differences between benign and malignant nodules in 2, 3 and 4 points were statistically significant (P<0.05). The manifestations of malignant nodules in UC were mostly the irregular shape, obscure boundary, no obvious enhancement, heterogeneous enhancement and visible perfusion defects, and there were statistically significant differences compared with the benign nodules (P<0.05). ROC curve showed that both sensitivity and specificity of UE and UC were superior to those of conventional US. AUC was the largest (AUC = 0.908) and the diagnostic value was the highest in the conventional US combined with UE and UC. Conventional US combined with elastography and UC can significantly improve the sensitivity, specificity and accuracy of diagnosis of benign and malignant thyroid nodules.

Multiple patterns of diblock copolymer confined in irregular geometries with soft surface

NASA Astrophysics Data System (ADS)

Li, Ying; Sun, Min-Na; Zhang, Jin-Jun; Pan, Jun-Xing; Guo, Yu-Qi; Wang, Bao-Feng; Wu, Hai-Shun

2015-12-01

The different confinement shapes can induce the formation of various interesting and novel morphologies, which might inspire potential applications of materials. In this paper, we study the directed self-assembly of diblock copolymer confined in irregular geometries with a soft surface by using self-consistent field theory. Two types of confinement geometries are considered, namely, one is the concave pore with one groove and the other is the concave pore with two grooves. We obtain more novel and different structures which could not be produced in other two-dimensional (2D) confinements. Comparing these new structures with those obtained in regular square confinement, we find that the range of ordered lamellae is enlarged and the range of disordered structure is narrowed down under the concave pore confinement. We also compare the different structures obtained under the two types of confinement geometries, the results show that the effect of confinement would increase, which might induce the diblock copolymer to form novel structures. We construct the phase diagram as a function of the fraction of B block and the ratio of h/L of the groove. The simulation reveals that the wetting effect of brushes and the shape of confinement geometries play important roles in determining the morphologies of the system. Our results improve the applications in the directed self-assembly of diblock copolymer for fabricating the irregular structures. Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20121404110004), the Research Foundation for Excellent Talents of Shanxi Provincial Department of Human Resources and Social Security, China, and the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province, China.

Femoral head shape differences during development may identify hips at risk of degeneration.

PubMed

Vanden Berg-Foels, Wendy S; Schwager, Steven J; Todhunter, Rory J; Reeves, Anthony P

2011-12-01

Developmental dysplasia of the hip (DDH) is a common cause of elevated contact stress and early onset osteoarthritis (OA). We hypothesized that adaptation to focal loading during postnatal development would result in signature changes to the shape of the femoral head secondary center of ossification (SCO). SCO shape was evaluated in a canine model of DDH at ages 14 and 32 weeks. The evolving 3D morphology of the SCO was captured using serial quantitative computed tomography. A discrete medial representation shape model was fit to each SCO and served as the basis for quantitative thickness and bending measurements. Shape measurements were tested for associations with hip subluxation and degeneration. At 32 weeks, the SCO was thinner (flatter) in the perifoveal region, the site of focal loading; a greater bend to the SCO was present lateral to the site of thinning; SCO thinning and bending were associated with less femoral head coverage and with a higher probability of degeneration. Shape changes were not detected at 14 weeks. Measurement and visualization of SCO shape changes due to altered loading may provide a basis for identifying hips at risk of early onset OA and a tool for surgical planning of hip restructuring.

Universal inverse design of surfaces with thin nematic elastomer sheets.

PubMed

Aharoni, Hillel; Xia, Yu; Zhang, Xinyue; Kamien, Randall D; Yang, Shu

2018-06-21

Programmable shape-shifting materials can take different physical forms to achieve multifunctionality in a dynamic and controllable manner. Although morphing a shape from 2D to 3D via programmed inhomogeneous local deformations has been demonstrated in various ways, the inverse problem-finding how to program a sheet in order for it to take an arbitrary desired 3D shape-is much harder yet critical to realize specific functions. Here, we address this inverse problem in thin liquid crystal elastomer (LCE) sheets, where the shape is preprogrammed by precise and local control of the molecular orientation of the liquid crystal monomers. We show how blueprints for arbitrary surface geometries can be generated using approximate numerical methods and how local extrinsic curvatures can be generated to assist in properly converting these geometries into shapes. Backed by faithfully alignable and rapidly lockable LCE chemistry, we precisely embed our designs in LCE sheets using advanced top-down microfabrication techniques. We thus successfully produce flat sheets that, upon thermal activation, take an arbitrary desired shape, such as a face. The general design principles presented here for creating an arbitrary 3D shape will allow for exploration of unmet needs in flexible electronics, metamaterials, aerospace and medical devices, and more.

PBP deletion mutants of Escherichia coli exhibit irregular distribution of MreB at the deformed zones.

PubMed

Vijayan, Saptha; Mallick, Sathi; Dutta, Mouparna; Narayani, M; Ghosh, Anindya S

2014-02-01

MreB is a cytoskeletal protein, which is responsible for maintaining proper cellular morphology and is essential for cell survival. Likewise, penicillin-binding protein 5 (PBP5) helps in maintaining cell shape, though non-essential for survival. The contradicting feature of these two proteins paves the way for this study, wherein we attempt to draw a relation on the nature of distribution of MreB in PBP deletion mutants. The study revealed that the uniform MreB helices/patches were destabilized/disturbed at the zone of deformities of the PBP mutants, whereas the helical patterns were retained at the regions maintaining a rod shape. We interpret that MreB remains functional irrespective of its distribution being misguided by the aberrant shapes of PBP mutants.

Deterministic diffusion in flower-shaped billiards.

PubMed

Harayama, Takahisa; Klages, Rainer; Gaspard, Pierre

2002-08-01

We propose a flower-shaped billiard in order to study the irregular parameter dependence of chaotic normal diffusion. Our model is an open system consisting of periodically distributed obstacles in the shape of a flower, and it is strongly chaotic for almost all parameter values. We compute the parameter dependent diffusion coefficient of this model from computer simulations and analyze its functional form using different schemes, all generalizing the simple random walk approximation of Machta and Zwanzig. The improved methods we use are based either on heuristic higher-order corrections to the simple random walk model, on lattice gas simulation methods, or they start from a suitable Green-Kubo formula for diffusion. We show that dynamical correlations, or memory effects, are of crucial importance in reproducing the precise parameter dependence of the diffusion coefficent.

Shape Effect Analysis of Aluminum Projectile Impact on Whipple Shields

NASA Technical Reports Server (NTRS)

Carrasquilla, Maria J.; Miller, Joshua E.

2017-01-01

The informed design with respect to hypervelocity collisions involving micrometeoroid and orbital debris (MMOD) is influential to the success of space missions. For an orbit comparable to that of the International Space Station, velocities for MMOD can range from 1 to 15 km/s, with an average velocity around 10 km/cu s. The high energy released during collisions at these speeds can result in damage to a spacecraft, or worst-case, loss of the spacecraft, thus outlining the importance of methods to predict the likelihood and extent of damage due to an impact. Through experimental testing and numerical simulations, substantial work has been conducted to better understand the effects of hypervelocity impacts (HVI) on spacecraft systems and shields; however, much of the work has been focused on spherical impacting particles. To improve environment models for the analysis of MMOD, a large-scale satellite break-up test was performed at the Arnold Engineering and Development Complex to better understand the varied impactor geometries that could be generated from a large impact. As a part of the post-experiment analysis, an undertaking to characterize the irregular fragments generated is currently being performed by the University of Florida under the management of NASA's Orbital Debris Program Office at Johnson Space Center (JSC). DebriSat was a representative, modern LEO satellite that was catastrophically broken up in a HVI test. The test chamber was lined with a soft-catch system of foam panels that captured the fragments after impact. Initial predictions put the number of fragments larger than 2mm generated from the HVI at roughly 85,000. The number of fragments thus far extracted from the foam panels has exceeded 100,000, with that number continuously increasing. The shapes of the fragments vary dependent upon the material. Carbon-fiber reinforced polymer pieces, for instance, are abundantly found as thin, flat slivers. The characterization of these fragments with respect to their mass, size, and material composition needs to be summarized in a form that can be used in MMOD analysis. The mechanism that brings these fragment traits into MMOD analysis is through ballistic limit equations (BLE) that have been developed largely for a few types of materials1. As a BLE provides the failure threshold for a shield or spacecraft component based on parameters such as the projectile impact velocity and size, and the target's materials, thickness, and configuration, it is used to design protective shields for spacecraft such as Whipple shields (WS) to an acceptable risk level. The majority of experiments and simulations to test shields and validate BLEs have, heretofore, largely used spheres as the impactor, not properly reflecting the irregular shapes of MMOD. This shortfall has motivated a numerical impact analysis study of HVI involving non-spherical geometries to identify key parameters that environment models should provide.

Manipulating femtosecond laser interactions in bulk glass and thin-film with spatial light modulation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Alimohammadian, Ehsan; Ho, Stephen; Ertorer, Erden; Gherghe, Sebastian; Li, Jianzhao; Herman, Peter R.

2017-03-01

Spatial Light Modulators (SLM) are emerging as a power tool for laser beam shaping whereby digitally addressed phase shifts can impose computer-generated hologram patterns on incoming laser light. SLM provide several additional advantages with ultrashort-pulsed lasers in controlling the shape of both surface and internal interactions with materials. Inside transparent materials, nonlinear optical effects can confine strong absorption only to the focal volume, extend dissipation over long filament tracks, or reach below diffraction-limited spot sizes. Hence, SLM beam shaping has been widely adopted for laser material processing applications that include parallel structuring, filamentation, fiber Bragg grating formation and optical aberration correction. This paper reports on a range of SLM applications we have studied in femtosecond processing of transparent glasses and thin films. Laser phase-fronts were tailored by the SLM to compensate for spherical surface aberration, and to further address the nonlinear interactions that interplay between Kerr-lens self-focusing and plasma defocusing effects over shallow and deep focusing inside the glass. Limits of strong and weak focusing were examined around the respective formation of low-loss optical waveguides and long uniform filament tracks. Further, we have employed the SLM for beam patterning inside thin film, exploring the limits of phase noise, resolution and fringe contrast during interferometric intra-film structuring. Femtosecond laser pulses of 200 fs pulse duration and 515 nm wavelength were shaped by a phase-only LCOS-SLM (Hamamatsu X10468-04). By imposing radial phase profiles, axicon, grating and beam splitting gratings, volume shape control of filament diameter, length, and uniformity as well as simultaneous formation of multiple filaments has been demonstrated. Similarly, competing effects of spherical surface aberration, self-focusing, and plasma de-focusing were studied and delineated to enable formation of low-loss optical waveguides over shallow and deep focusing conditions. Lastly, SLM beam shaping has been successfully extended to interferometric processing inside thin transparent film, enabling the arbitrary formation of uniform or non-uniform, symmetric or asymmetric patterns of flexible shape on nano-scale dimensions without phase-noise degradation by the SLM patterning. We present quantized structuring of thin films by a single laser pulse, demonstrating λ/2nfilm layer ejection control, blister formation, nano-cavities, and film colouring. Closed intra-film nanochannels with high aspect ratio (20:1) have been formed inside 3.5 um thick silica, opening new prospects for sub-cellular studies and lab-in-film concepts that integrate on CMOS silicon technologies.

Spectroscopic ellipsometry analysis of a thin film composite membrane consisting of polysulfone on a porous α-alumina support.

PubMed

Ogieglo, Wojciech; Wormeester, Herbert; Wessling, Matthias; Benes, Nieck E

2012-02-01

Exposure of a thin polymer film to a fluid can affect properties of the film such as the density and thickness. In particular in membrane technology, these changes can have important implications for membrane performance. Spectroscopic ellipsometry is a convenient technique for in situ studies of thin films, because of its noninvasive character and very high precision. The applicability of spectroscopic ellipsometry is usually limited to samples with well-defined interfacial regions, whereas in typical composite membranes, often substantial and irregular intrusion of the thin film into the pores of a support exists. In this work, we provide a detailed characterization of a polished porous alumina membrane support, using variable-angle spectroscopic ellipsometry in combination with atomic force microscopy and mercury porosimetry. Two Spectroscopic ellipsometry optical models are presented that can adequately describe the surface roughness of the support. These models consider the surface roughness as a distinct layer in which the porosity gradually increases toward the outer ambient interface. The first model considers the porosity profile to be linear; the second model assumes an exponential profile. It is shown that the models can be extended to account for a composite membrane geometry, by deposition of a thin polysulfone film onto the support. The developed method facilitates practicability for in situ spectroscopic ellipsometry studies of nonequilibrium systems, i.e., membranes under actual permeation conditions.

Variscan deformation along the Teisseyre-Tornquist Zone in SE Poland: Thick-skinned structural inheritance or thin-skinned thrusting?

NASA Astrophysics Data System (ADS)

Krzywiec, P.; Gągała, Ł.; Mazur, S.; Słonka, Ł.; Kufrasa, M.; Malinowski, M.; Pietsch, K.; Golonka, J.

2017-10-01

Recently acquired seismic reflection data provide better insight in the structural style of extensive sedimentary series overlying the SW slope of the East European Craton (EEC) in Poland. The two main seismic datasets - the POLCRUST-01 profile and PolandSPAN survey - yielded contrasting thick - and thin-skinned structural models for the same structural units in SE Poland. We reattempt an interpretation of the POLCRUST-01 profile using techniques of cross-section balancing and restoration aided by 2D forward seismic modelling. An outcome is the thin-skinned structural model is. This solution relies on a continuous top of the EEC crystalline basement well represented in the seismic data as well as on fragmentary, yet conclusive seismic geometries in shallow depth intervals proving the Ediacaran-Palaeozoic series to be thrust and folded. A Variscan (late Carboniferous) compressional regime is consequently invoked to explain thin-skinned structuring of the pre-Permian sedimentary pile and > 20 km of calculated shortening. We demonstrate an ambiguous nature of the top-basement irregularities previously used as indicators of basement-rooted vertical faulting. The tilt and abrupt increase of the top-basement taper under the thin-skinned belt are attributed to pre-Ordovician tectonic processes operating along the SW margin of the EEC. Post-rift subsidence and/or flexural loading giving rise to a broken foreland plate are invoked.

SATSIN System Manual.

DTIC Science & Technology

1995-01-01

This report outlines the design, functions and operation of the HAARP Diagnostic Satellite Scintillation (SATSIN) system that will be used to...be located so that the propagation path from satellite radio beacons passes through the heated volume created by HAARP . The signal, altered in phase...characteristics of the scintillation. From this information, the strength, shape and motion of the in situ irregularities generated by HAARP can be implied. The

Internal Tidal Hydrodynamics and Ambient Characteristics of the Adriatic (ITHACA)

DTIC Science & Technology

2006-12-31

document atmospheric conditions along the line extending from the coast to the open sea. 2.1. Measuring sites Position of meteorological measuring sites...idealized case, they are perpendicular to the straight shoreline. However, along the eastern Adriatic irregularly shaped coast there is a number of...Cvitan, 2003; Belusic et al., 2004; Belusic and Klaic, 2004, 2006), southwestward, downslope windstorm , which frequently blows over the Adriatic

Pulsed source ion implantation apparatus and method

DOEpatents

Leung, Ka-Ngo

1996-01-01

A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted.

Method of casting aerogels

DOEpatents

Poco, John F.

1993-01-01

The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

Callicarpa americana L.

Treesearch

K.F Connor

2004-01-01

American beautyberry is a shrub that can reach 2.4 to 2.7 m in height but is typically shorter, averaging 0.9 to 1.8 m. The irregular, spreading bush has an open growth habit and grows as a single plant or in colonies. Bark is brown and raised lenticels are found on older stems. The opposite, short-petioled, simple, deciduous leaves are ovate to elliptic in shape. They...

The Long War Concept: Using the Security Cooperation Marine Air Ground Task Force to Address Irregular Threats through Shaping and Deterrence

DTIC Science & Technology

2008-01-01

8217 relationships and alliances and/or deter potenrlal advetsaries. • PlltlSE 1: Deter the Enem ~’, This phase focuses on deterring specific opponents by...destruction of the enem ~’ in ol’der to break the opponent’s will for organized resistance. StabIllty operations WIll also be conducted as needed to

Further evidence that rats rely on local rather than global spatial information to locate a hidden goal: reply to Cheng and Gallistel (2005).

PubMed

McGregor, Anthony; Jones, Peter M; Good, Mark A; Pearce, John M

2006-07-01

Naive male Hooded Lister rats (Rattus norvegicus) were required to find a submerged platform in a right-angled corner between a long and a short wall of a pool in the shape of an irregular pentagon. Tests in a rectangular pool revealed a preference for the corners that corresponded with the correct corner in the pentagon. These findings indicate that rats identified the correct corner in the pentagon by local cues. They contradict the suggestion that rats navigate by moving in a particular direction relative to the principal axis of the shape of their environment.

A variable resolution right TIN approach for gridded oceanographic data

NASA Astrophysics Data System (ADS)

Marks, David; Elmore, Paul; Blain, Cheryl Ann; Bourgeois, Brian; Petry, Frederick; Ferrini, Vicki

2017-12-01

Many oceanographic applications require multi resolution representation of gridded data such as for bathymetric data. Although triangular irregular networks (TINs) allow for variable resolution, they do not provide a gridded structure. Right TINs (RTINs) are compatible with a gridded structure. We explored the use of two approaches for RTINs termed top-down and bottom-up implementations. We illustrate why the latter is most appropriate for gridded data and describe for this technique how the data can be thinned. While both the top-down and bottom-up approaches accurately preserve the surface morphology of any given region, the top-down method of vertex placement can fail to match the actual vertex locations of the underlying grid in many instances, resulting in obscured topology/bathymetry. Finally we describe the use of the bottom-up approach and data thinning in two applications. The first is to provide thinned, variable resolution bathymetry data for tests of storm surge and inundation modeling, in particular hurricane Katrina. Secondly we consider the use of the approach for an application to an oceanographic data grid of 3-D ocean temperature.

Thin-plate spline quadrature of geodetic integrals

NASA Technical Reports Server (NTRS)

Vangysen, Herman

1989-01-01

Thin-plate spline functions (known for their flexibility and fidelity in representing experimental data) are especially well-suited for the numerical integration of geodetic integrals in the area where the integration is most sensitive to the data, i.e., in the immediate vicinity of the evaluation point. Spline quadrature rules are derived for the contribution of a circular innermost zone to Stoke's formula, to the formulae of Vening Meinesz, and to the recursively evaluated operator L(n) in the analytical continuation solution of Molodensky's problem. These rules are exact for interpolating thin-plate splines. In cases where the integration data are distributed irregularly, a system of linear equations needs to be solved for the quadrature coefficients. Formulae are given for the terms appearing in these equations. In case the data are regularly distributed, the coefficients may be determined once-and-for-all. Examples are given of some fixed-point rules. With such rules successive evaluation, within a circular disk, of the terms in Molodensky's series becomes relatively easy. The spline quadrature technique presented complements other techniques such as ring integration for intermediate integration zones.

Health and Beauty Magazine Reading and Body Shape Concerns among a Group of College Women.

ERIC Educational Resources Information Center

Thomsen, Steven R.

2002-01-01

Examines three potential factors that might mediate the relationship between reading women's magazines and body shape and size concern. Finds that health and fitness magazine reading by college-aged women was linked directly to body shape concerns, indirectly through beliefs about men's thinness expectations. Explains that beauty and fashion…

Female and Male Perceptions of Ideal Body Shapes: Distorted Views among Caucasian College Students.

ERIC Educational Resources Information Center

Cohn, Lawrence D.; Adler, Nancy E.

1992-01-01

Using body silhouettes, 87 college women and 118 college men indicated their own body shapes and shapes they and same-sex and other-sex peers find most attractive. Focus was on whether women overestimate desirability of thin figures among female peers. Males and females misjudged same-sex peers' preferences compared with ideals. (SLD)

Earth Observations by the Expedition 19 crew

NASA Image and Video Library

2009-04-09

ISS019-E-005989 (9 April 2009) --- Red River floods in North Dakota and Minnesota are featured in this image photographed by an Expedition 19 crewmember on the International Space Station. The Red River, which flows north between North Dakota and Minnesota, flooded for a second time on the day this image was taken (9 April 2009). Two weeks earlier the river had crested at very high levels. The new floodwaters in the Red River, and especially in the less well-drained meandering tributaries east of the river, appear as black shapes against a snowy agricultural landscape defined by rectangular fields. The largest irregular black patches are the flooded low parts of fields along a canalized western tributary of the Red River (right). The city-block patterns of Wahpeton ND and Breckenridge MN, opposite one another on the banks of the Red River, stand out as dark gray patches against the snow at image top left. The main runway of the Henry Stern Airport lies angled northwest directly south of Wahpeton, and its 1.3 kilometers runway length gives scale to the view. Access roads to the agricultural fields tend to follow an orthogonal pattern, while larger roads leading to the cities cut across this pattern (lower left, near Wahpeton). A subtle pattern of drainage ditches and plow lines appear as thin parallel lines throughout fields in the scene.

Physical conditions for trapping air by a microtrichia-covered insect cuticle during temporary submersion

NASA Astrophysics Data System (ADS)

Neumann, Dietrich; Woermann, Dietrich

2009-08-01

The intertidal midge Clunio, which reproduces on exposed rocky seashores, becomes enclosed in an irregularly shaped air bubble during short submersion by incoming waves. This water-repellent property of Clunio’s cuticle is caused by a complete cover of hydrophobic microtrichia offering an effective surf tolerance. These microtrichia not only trap a thin air layer above the cuticle but also maintain a larger air bubble between the insect’s ventral side and legs. The effectiveness of the water repellence was quantitatively characterised on the basis of a known model (Crisp and Thorpe, Discuss Faraday Soc 3:210-220, 1948). The parameters of the model are the contact angle θ (>90°) at the contact line of air/water/microtrichia and the distance between individual microtrichia and their radius. When the microtrichia are 1.1 μm apart and have a radius of 0.1 μm and an estimated contact angle θ of 140°, the air layer is stable against hydrostatic pressures of up to 3 m water column. As shown by a modified version of the model, considerably larger air bubbles can be trapped by the microtrichia cover of the legs up to distances of 0.5 mm from the body. The widely spaced (about 8 μm apart) and longer setae of Clunio are not involved in the formation of air layers and air bubble.

Psoriasis or not? Review of 51 clinically confirmed cases reveals an expanded histopathologic spectrum of psoriasis.

PubMed

Chau, Thinh; Parsi, Kory K; Ogawa, Toru; Kiuru, Maija; Konia, Thomas; Li, Chin-Shang; Fung, Maxwell A

2017-12-01

Psoriasis is usually diagnosed clinically, so only non-classic or refractory cases tend to be biopsied. Diagnostic uncertainty persists when dermatopathologists encounter features regarded as non-classic for psoriasis. Define and document classic and non-classic histologic features in skin biopsies from patients with clinically confirmed psoriasis. Minimal clinical diagnostic criteria were informally validated and applied to a consecutive series of biopsies histologically consistent with psoriasis. Clinical confirmation required 2 of the following criteria: (1) classic morphology, (2) classic distribution, (3) nail pitting, and (4) family history, with #1 and/or #2 as 1 criterion in every case RESULTS: Fifty-one biopsies from 46 patients were examined. Classic features of psoriasis included hypogranulosis (96%), club-shaped rete ridges (96%), dermal papilla capillary ectasia (90%), Munro microabscess (78%), suprapapillary plate thinning (63%), spongiform pustules (53%), and regular acanthosis (14%). Non-classic features included irregular acanthosis (84%), junctional vacuolar alteration (76%), spongiosis (76%), dermal neutrophils (69%), necrotic keratinocytes (67%), hypergranulosis (65%), neutrophilic spongiosis (61%), dermal eosinophils (49%), compact orthokeratosis (37%), papillary dermal fibrosis (35%), lichenoid infiltrate (25%), plasma cells (16%), and eosinophilic spongiosis (8%). Psoriasis exhibits a broader histopathologic spectrum. The presence of some non-classic features does not necessarily exclude the possibility of psoriasis. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Earth Observations taken by the Expedition 18 Crew

NASA Image and Video Library

2008-12-03

ISS018-E-010206 (3 Dec. 2008) --- Mount Nemrut in Turkey is featured in this image photographed by an Expedition 18 crewmember on the International Space Station. This detailed view centers on the summit caldera of Mount Nemrut (Nemrut Dagi in Turkish), a stratovolcano located in the eastern Anatolia region of Turkey along the shoreline of Lake Van. Winter snow blankets the 2,948 meter elevation summit of the mountain, highlighting the brown caldera rim (a caldera is a large, usually circular or elliptical, collapse feature caused by the rapid emptying of an underlying magma chamber). The snow also highlights the irregular shape and wrinkled surfaces of several lava flows present in the eastern portion of the caldera. Lava flows associated with Mt. Nemrut range in composition from thin, fluid basalt to thick, glassy obsidian. A coldwater caldera lake occupies the western half of the summit. The geologic record at Mt. Nemrut indicates numerous prehistoric explosive eruptions during the Holocene Epoch ?which, according to scientists, began approximately 10,000 years ago and extends to the present day ? with eruption of lava last observed during 1441. The last well-documented explosive eruption occurred during 1650. Volcanism at Mt. Nemrut is the result of tectonic activity associated with the collision of the Arabian and Eurasian Plates; this collision is ongoing, and the presence of a warm water lake in the caldera suggests that the volcano is merely quiescent at present.

Interference effects in the sum frequency generation spectra of thin organic films. II: Applications to different thin-film systems.

PubMed

Tong, Yujin; Zhao, Yanbao; Li, Na; Ma, Yunsheng; Osawa, Masatoshi; Davies, Paul B; Ye, Shen

2010-07-21

In this paper, the results of the modeling calculations carried out for predicting the interference effects expected in the sum frequency generation (SFG) spectra of a specific thin-layer system, described in the accompanying paper, are tested by comparing them with the experimental spectra obtained for a real thin-layer film comprising an organic monolayer/variable thickness dielectric layer/gold substrate. In this system, two contributions to the SFG spectra arise, a resonant contribution from the organic film and a nonresonant contribution from the gold substrate. The modeling calculations are in excellent agreement with the experimental spectra over a wide range of thicknesses and for different polarization combinations. The introduction of another resonant monolayer adjacent to the gold substrate and with the molecules having a reverse orientation has a significant affect on the spectral shapes which is predicted. If a dielectric substrate such as CaF(2) is used instead of a gold substrate, only the spectral intensities vary with the film thickness but not the spectral shapes. The counterpropagating beam geometry will change both the thickness dependent spectral shapes and the intensity of different vibrational modes in comparison with a copropagating geometry. The influences of these experimental factors, i.e., the molecular orientational structure in the thin film, the nature of the substrate, and the selected incident beam geometry, on the experimental SFG spectra are quantitatively predicted by the calculations. The thickness effects on the signals from a SFG active monolayer contained in a thin liquid-layer cell of the type frequently used for in situ electrochemical measurements is also discussed. The modeling calculation is also valid for application to other thin-film systems comprising more than two resonant SFG active interfaces by appropriate choice of optical geometries and relevant optical properties.

Tailoring plasmonic properties of metal nanoparticle-embedded dielectric thin films: the sandwich method of preparation

NASA Astrophysics Data System (ADS)

Laha, Ranjit; Malar, P.; Osipowicz, Thomas; Kasiviswanathan, S.

2017-09-01

Tailoring of plasmonic properties of metal nanoparticle-embedded dielectric thin films are very crucial for many thin film-based applications. We, herein, investigate the various ways of tuning the plasmonic positions of gold nanoparticles (AuNPs)-embedded indium oxide thin films (Au:IO) through a sequence-specific sandwich method. The sandwich method is a four-step process involving deposition of In2O3 film by magnetron sputtering in first and fourth steps, thermal evaporation of Au on to In2O3 film in second and annealing of Au/In2O3 film in the third step. The Au:IO films were characterized by x-ray diffraction, spectrophotometry and transmission electron microscopy. The size and shape of the embedded nanoparticles were found from Rutherford back-scattering spectrometry. Based on dynamic Maxwell Garnett theory, the observed plasmon resonance position was ascribed to the oblate shape of AuNPs formed in sandwich method. Finally, through experimental data, it was shown that the plasmon resonance position of Au:IO thin films can be tuned by 125 nm. The method shown here can be used to tune the plasmon resonance position over the entire range of visible region for the thin films made from other combinations of metal-dielectric pair.

Effects of magnetic-storm phases on F-layer irregularities from auroral to equatorial latitudes. Quarterly report, 1 Jan-31 Mar 92

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

Aarons, J.; Mendillo, M.

Determining the morphology of F layer irregularities as a function of longitude in the equatorial region is vital for understanding the physics of the development of these irregularities. We aim to lay the observational basis which then can be used to test theoretical models. Theoretical models have been developed, notably the papers by R.T. Tsunoda (Rev. Geophys. 26, 719, 1988) and by T. Maruyama and N. Matuura (J. Geophys. Res. 89, 10903, 1984). The question is whether the models are consistent with the morphology as we see it. According to our criteria, the data used should be confined to observationsmore » taken near the magnetic equator during quiet magnetic periods and at times within a few hours after sunset. Anomaly region data should be omitted for studying the generation mechanism. The questions to be answered by proposed mechanisms are: (1) why do the equinox months have high levels of occurrence over all longitudes; (2) why are there relatively high levels of occurrence in the Central Pacific Sector in the July-August period and in the 0-75 deg West Sector in the November-December period; and (3) why are there very low levels of occurrence in November and December in the Central Pacific Sector and in July and August in the 0-75 deg West Sector. Satellite in-situ data, scintillation and spread F observations will be reviewed. The limitation of each data set will be outlined particularly as relevant to the bias produced by the existence of thin versus extended layers of irregularities. A cartoon as to the occurrence pattern, as we see it, as a function of longitude will be shown.« less

Non-ellipsoidal inclusions as geological strain markers and competence indicators

NASA Astrophysics Data System (ADS)

Treagus, S. H.; Hudleston, P. J.; Lan, L.

1996-09-01

Geological objects that do not deform homogeneously with their matrix can be considered as inclusions with viscosity contrast. Such inclusions are generally treated as initially spherical or ellipsoidal. Theory shows that ellipsoidal inclusions deform homogeneously, so they maintain an ellipsoidal shape, regardless of the viscosity difference. However, non-ellipsoidal inclusions deform inhomogeneously, so will become irregular in shape. Geological objects such as porphyroblasts, porphyroclasts and sedimentary clasts are likely to be of this kind, with initially rectilinear, prismatic or superelliptical section shapes. We present two-dimensional finite-element models of deformed square inclusions, in pure shear (parallel or diagonal to the square), as a preliminary investigation of the deformation of non-ellipsoidal inclusions with viscosity contrast. Competent inclusions develop marked barrel shapes with horn-like corners, as described for natural ductile boudins, or slightly wavy rhombs. Incompetent inclusions develop 'dumb-bell' or bone shapes, with a surprising degree of bulging of the shortened edges, or rhomb to sheath shapes. The results lead to speculation for inclusions in the circle to square shape range, and for asymmetric orientations. Anticipated shapes range from asymmetric barrels, lemons or flags for competent inclusions, to ribbon or fish shapes for incompetent inclusions. We conclude that shapes of inclusions and clasts provide an important new type of strain marker and competence criterion.

In vivo imaging of coin-shaped lesions in cytomegalovirus corneal endotheliitis by anterior segment optical coherence tomography.

PubMed

Yokogawa, Hideaki; Kobayashi, Akira; Yamazaki, Natsuko; Sugiyama, Kazuhisa

2014-12-01

The aim of this study was to investigate in vivo corneal changes of coin-shaped lesions in cytomegalovirus corneal endotheliitis using anterior segment optical coherence tomography (AS-OCT). Two eyes of 2 patients (69- and 71-year-old men), with polymerase chain reaction-proven CMV corneal endotheliitis presenting coin-shaped lesions, were included in this study. AS-OCT examination was performed on the initial visit and at follow-up visits by paying special attention to the coin-shaped lesions. Selected AS-OCT images of the cornea were evaluated qualitatively for changes in the shape and degree of light reflection. In both cases, coin-shaped lesions were observed at the corneal endothelial surface as clusters of fine precipitates using slit-lamp biomicroscopy. Using AS-OCT, high-resolution images of the putative coin-shaped lesions were successfully obtained in both patients as an irregularly thickened highly reflective endothelial cell layer. After anti-CMV treatment, the coin-shaped lesions were resolved as assessed by slit-lamp biomicroscopy and AS-OCT in both patients. High-resolution AS-OCT provides novel and detailed visual information of coin-shaped lesions in patients with CMV corneal endotheliitis. Visualization of coin-shaped lesions by AS-OCT may be a useful adjunct to the diagnosis and follow-up of CMV corneal endotheliitis.

A two-dimensional composite grid numerical model based on the reduced system for oceanography

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

Xie, Y.F.; Browning, G.L.; Chesshire, G.

The proper mathematical limit of a hyperbolic system with multiple time scales, the reduced system, is a system that contains no high-frequency motions and is well posed if suitable boundary conditions are chosen for the initial-boundary value problem. The composite grid method, a robust and efficient grid-generation technique that smoothly and accurately treats general irregular boundaries, is used to approximate the two-dimensional version of the reduced system for oceanography on irregular ocean basins. A change-of-variable technique that substantially increases the accuracy of the model and a method for efficiently solving the elliptic equation for the geopotential are discussed. Numerical resultsmore » are presented for circular and kidney-shaped basins by using a set of analytic solutions constructed in this paper.« less

Full two-dimensional transient solutions of electrothermal aircraft blade deicing

NASA Technical Reports Server (NTRS)

Masiulaniec, K. C.; Keith, T. G., Jr.; Dewitt, K. J.; Leffel, K. L.

1985-01-01

Two finite difference methods are presented for the analysis of transient, two-dimensional responses of an electrothermal de-icer pad of an aircraft wing or blade with attached variable ice layer thickness. Both models employ a Crank-Nicholson iterative scheme, and use an enthalpy formulation to handle the phase change in the ice layer. The first technique makes use of a 'staircase' approach, fitting the irregular ice boundary with square computational cells. The second technique uses a body fitted coordinate transform, and maps the exact shape of the irregular boundary into a rectangular body, with uniformally square computational cells. The numerical solution takes place in the transformed plane. Initial results accounting for variable ice layer thickness are presented. Details of planned de-icing tests at NASA-Lewis, which will provide empirical verification for the above two methods, are also presented.

Quantification of the spatial strain distribution of scoliosis using a thin-plate spline method.

PubMed

Kiriyama, Yoshimori; Watanabe, Kota; Matsumoto, Morio; Toyama, Yoshiaki; Nagura, Takeo

2014-01-03

The objective of this study was to quantify the three-dimensional spatial strain distribution of a scoliotic spine by nonhomogeneous transformation without using a statistically averaged reference spine. The shape of the scoliotic spine was determined from computed tomography images from a female patient with adolescent idiopathic scoliosis. The shape of the scoliotic spine was enclosed in a rectangular grid, and symmetrized using a thin-plate spline method according to the node positions of the grid. The node positions of the grid were determined by numerical optimization to satisfy symmetry. The obtained symmetric spinal shape was enclosed within a new rectangular grid and distorted back to the original scoliotic shape using a thin-plate spline method. The distorted grid was compared to the rectangular grid that surrounded the symmetrical spine. Cobb's angle was reduced from 35° in the scoliotic spine to 7° in the symmetrized spine, and the scoliotic shape was almost fully symmetrized. The scoliotic spine showed a complex Green-Lagrange strain distribution in three dimensions. The vertical and transverse compressive/tensile strains in the frontal plane were consistent with the major scoliotic deformation. The compressive, tensile and shear strains on the convex side of the apical vertebra were opposite to those on the concave side. These results indicate that the proposed method can be used to quantify the three-dimensional spatial strain distribution of a scoliotic spine, and may be useful in quantifying the deformity of scoliosis. © 2013 Elsevier Ltd. All rights reserved.

Role for Macrophage Metalloelastase in Glomerular Basement Membrane Damage Associated with Alport Syndrome

PubMed Central

Rao, Velidi H.; Meehan, Daniel T.; Delimont, Duane; Nakajima, Motowo; Wada, Takashi; Ann Gratton, Michael; Cosgrove, Dominic

2006-01-01

Alport syndrome is a glomerular basement membrane (GBM) disease caused by mutations in type IV collagen genes. A unique irregular thickening and thinning of the GBM characterizes the progressive glomerular pathology. The metabolic imbalances responsible for these GBM irregularities are not known. Here we show that macrophage metalloelastase (MMP-12) expression is >40-fold induced in glomeruli from Alport mice and is markedly induced in glomeruli of both humans and dogs with Alport syndrome. Treatment of Alport mice with MMI270 (CGS27023A), a broad spectrum MMP inhibitor that blocks MMP-12 activity, results in largely restored GBM ultrastructure and function. Treatment with BAY-129566, a broad spectrum MMP inhibitor that does not inhibit MMP-12, had no effect. We show that inhibition of CC chemokine receptor 2 (CCR2) receptor signaling with propagermanium blocks induction of MMP-12 mRNA and prevents GBM damage. CCR2 receptor is expressed in glomerular podocytes of Alport mice, suggesting MCP-1 activation of CCR2 on podocytes may underlie induction of MMP-12. These data indicate that the irregular GBM that characterizes Alport syndrome may be mediated, in part, by focal degradation of the GBM due to MMP dysregulation, in particular, MMP-12. Thus, MMP-12/CCR2 inhibitors may provide a novel and effective therapeutic strategy for Alport glomerular disease. PMID:16816359

Cancer-associated retinopathy with unusual retinal whitening.

PubMed

Lee, Joan J; Vrabec, Tamara R; Baldassano, Vincent F

2015-01-01

To describe the clinical characteristics and results of ocular and systemic testing in an atypical case of cancer-associated retinopathy. This study is a retrospective case report of a female patient. Rapidly progressive visual loss, vitritis, white, ring- and coin-shaped retinal lesions, and panretinal optical coherence tomography thinning preceded the diagnosis of poorly differentiated cervical carcinoma with neuroendocrine features consistent with small-cell carcinoma. Cancer-associated retinopathy can present with ring- and coin-shaped retinal lesions, vitritis, and panretinal thinning. The presence of intraocular inflammation and retinal and choroidal vasculopathy may herald more rapid visual demise.

Vision system and three-dimensional modeling techniques for quantification of the morphology of irregular particles

NASA Astrophysics Data System (ADS)

Smith, Lyndon N.; Smith, Melvyn L.

2000-10-01

Particulate materials undergo processing in many industries, and therefore there are significant commercial motivators for attaining improvements in the flow and packing behavior of powders. This can be achieved by modeling the effects of particle size, friction, and most importantly, particle shape or morphology. The method presented here for simulating powders employs a random number generator to construct a model of a random particle by combining a sphere with a number of smaller spheres. The resulting 3D model particle has a nodular type of morphology, which is similar to that exhibited by the atomized powders that are used in the bulk of powder metallurgy (PM) manufacture. The irregularity of the model particles is dependent upon vision system data gathered from microscopic analysis of real powder particles. A methodology is proposed whereby randomly generated model particles of various sized and irregularities can be combined in a random packing simulation. The proposed Monte Carlo technique would allow incorporation of the effects of gravity, wall friction, and inter-particle friction. The improvements in simulation realism that this method is expected to provide would prove useful for controlling powder production, and for predicting die fill behavior during the production of PM parts.

Novel edge treatment method for improving the transmission reconstruction quality in Tomographic Gamma Scanning.

PubMed

Han, Miaomiao; Guo, Zhirong; Liu, Haifeng; Li, Qinghua

2018-05-01

Tomographic Gamma Scanning (TGS) is a method used for the nondestructive assay of radioactive wastes. In TGS, the actual irregular edge voxels are regarded as regular cubic voxels in the traditional treatment method. In this study, in order to improve the performance of TGS, a novel edge treatment method is proposed that considers the actual shapes of these voxels. The two different edge voxel treatment methods were compared by computing the pixel-level relative errors and normalized mean square errors (NMSEs) between the reconstructed transmission images and the ideal images. Both methods were coupled with two different interative algorithms comprising Algebraic Reconstruction Technique (ART) with a non-negativity constraint and Maximum Likelihood Expectation Maximization (MLEM). The results demonstrated that the traditional method for edge voxel treatment can introduce significant error and that the real irregular edge voxel treatment method can improve the performance of TGS by obtaining better transmission reconstruction images. With the real irregular edge voxel treatment method, MLEM algorithm and ART algorithm can be comparable when assaying homogenous matrices, but MLEM algorithm is superior to ART algorithm when assaying heterogeneous matrices. Copyright © 2018 Elsevier Ltd. All rights reserved.

High-field magnets using high-critical-temperature superconducting thin films

DOEpatents

Mitlitsky, F.; Hoard, R.W.

1994-05-10

High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla are disclosed. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field. 4 figures.

High-field magnets using high-critical-temperature superconducting thin films

DOEpatents

Mitlitsky, Fred; Hoard, Ronald W.

1994-01-01

High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field.

Meshless Solution of the Problem on the Static Behavior of Thin and Thick Laminated Composite Beams

NASA Astrophysics Data System (ADS)

Xiang, S.; Kang, G. W.

2018-03-01

For the first time, the static behavior of laminated composite beams is analyzed using the meshless collocation method based on a thin-plate-spline radial basis function. In the approximation of a partial differential equation by using a radial basis function, the shape parameter has an important role in ensuring the numerical accuracy. The choice of a shape parameter in the thin plate spline radial basis function is easier than in other radial basis functions. The governing differential equations are derived based on Reddy's third-order shear deformation theory. Numerical results are obtained for symmetric cross-ply laminated composite beams with simple-simple and cantilever boundary conditions under a uniform load. The results found are compared with available published ones and demonstrate the accuracy of the present method.

Systematic description of the effect of particle shape on the strength properties of granular media

NASA Astrophysics Data System (ADS)

Azéma, Emilien; Estrada, Nicolas; Preechawuttipong, Itthichai; Delenne, Jean-Yves; Radjai, Farhang

2017-06-01

In this paper, we explore numerically the effect of particle shape on the mechanical behavior of sheared granular packings. In the framework of the Contact Dynamic (CD)Method, we model angular shape as irregular polyhedral particles, non-convex shape as regular aggregates of four overlapping spheres, elongated shape as rounded cap rectangles and platy shape as square-plates. Binary granular mixture consisting of disks and elongated particles are also considered. For each above situations, the number of face of polyhedral particles, the overlap of spheres, the aspect ratio of elongated and platy particles, are systematically varied from spheres to very angular, non-convex, elongated and platy shapes. The level of homogeneity of binary mixture varies from homogenous packing to fully segregated packings. Our numerical results suggest that the effects of shape parameters are nonlinear and counterintuitive. We show that the shear strength increases as shape deviate from spherical shape. But, for angular shapes it first increases up to a maximum value and then saturates to a constant value as the particles become more angular. For mixture of two shapes, the strength increases with respect of the increase of the proportion of elongated particles, but surprisingly it is independent with the level of homogeneity of the mixture. A detailed analysis of the contact network topology, evidence that various contact types contribute differently to stress transmission at the micro-scale.

Physiological identification of morphologically distinct afferent classes innervating the cristae ampullares of the squirrel monkey

NASA Technical Reports Server (NTRS)

Lysakowski, A.; Minor, L. B.; Fernandez, C.; Goldberg, J. M.

1995-01-01

1. Semicircular-canal afferents in the squirrel monkey were characterized by their resting discharge, discharge regularity, sensitivity to galvanic currents delivered to the ear (beta *), the gain (g2Hz), and phase lead (phi 2Hz) of their response to 2-Hz sinusoidal head rotations, and their antidromic conduction velocity. Discharge regularity was measured by a normalized coefficient of variation (CV*); the higher the CV*, the more irregular the discharge. g2Hz and phi 2Hz were expressed relative to angular head velocity. 2. These physiological measures were used in an attempt to discern the discharge properties of the three morphological classes of afferents innervating the crista. Presumed bouton (B) fibers were identified as slowly conducting afferents. Presumed calyx (C) fibers were recognized by their irregular discharge and low rotational gains. The remaining fibers were considered to be dimorphic (D) units. Single letters (B, C, and D) are used to emphasize that the classification is based on circumstantial evidence and may be wrong for individual fibers. Of the 125 identified fibers, 13 (10%) were B units, 36 (29%) were C units, and 76 (61%) were D units. 3. B units were regularly discharging D units ranged from regularly to irregularly discharging. C units were the most irregularly discharging afferents encountered. The mean resting discharge for the entire sample was 74 spikes/s. Resting rates were similar for regularly discharging B and D units and higher than those for irregularly discharging C and D units. 4. Except for their lower conduction velocities, the discharge properties of B units are indistinguishable from those of regularly discharging D units. Many of the discharge properties of B and D units vary with discharge regularity. There is a strong, positive relation when beta *, g2Hz, or phi 2Hz is plotted against CV*. For beta * or phi 2Hz, C units conform to the relation for B and D units. In contrast, values of g2Hz for C units are three to four times lower than predicted from the relation for the other two classes. 5. Internal (axon) diameters (dp) of peripheral vestibular-nerve fibers were estimated from central antidromic conduction velocities. Thick fibers (dp > or = 49 microns) were irregularly discharging, mostly C units. Medium-sized fibers (dp = 1.5-4 microns) included regular, intermediate, and irregular D units, as well as C units. Thin fibers (dp < or = 1.5 microns) were defined as B units.(ABSTRACT TRUNCATED AT 400 WORDS).

Seamless growth of a supramolecular carpet

PubMed Central

Kim, Ju-Hyung; Ribierre, Jean-Charles; Yang, Yu Seok; Adachi, Chihaya; Kawai, Maki; Jung, Jaehoon; Fukushima, Takanori; Kim, Yousoo

2016-01-01

Organic/metal interfaces play crucial roles in the formation of intermolecular networks on metal surfaces and the performance of organic devices. Although their purity and uniformity have profound effects on the operation of organic devices, the formation of organic thin films with high interfacial uniformity on metal surfaces has suffered from the intrinsic limitation of molecular ordering imposed by irregular surface structures. Here we demonstrate a supramolecular carpet with widely uniform interfacial structure and high adaptability on a metal surface via a one-step process. The high uniformity is achieved with well-balanced interfacial interactions and site-specific molecular rearrangements, even on a pre-annealed amorphous gold surface. Co-existing electronic structures show selective availability corresponding to the energy region and the local position of the system. These findings provide not only a deeper insight into organic thin films with high structural integrity, but also a new way to tailor interfacial geometric and electronic structures. PMID:26839053

Thin-phase screen estimates of TID effects on midlatitude transionospheric radio paths

NASA Astrophysics Data System (ADS)

Reilly, Michael H.

1993-11-01

The thin-phase screen model for ionospheric irregularity perturbations to transionospheric radio propagation is redefined. It is argued that the phase screen normal should be along the line of sight (LOS) between a receiver on the ground and a space transmitter, rather than in the zenith direction at the point of intersection with the LOS, which is traditional. The model is applied to a calculation of TID strength thresholds for the occurrence of multipath and scintillation. The results are in sharp disagreement with the traditional model, which predicts thresholds lower by an order of magnitude in typical cases. Midlatitude observations of TID strengths are reviewed, and it is found that multipath thresholds can be exceeded under one or more favorable circumstances, which include frequencies below about 100 MHz, low elevation angles, winter, night, atmospheric gravity wave velocity near the magnetic field direction and away from parallel with the LOS, and low solar activity.

Self-assembled morphologies of an amphiphilic Y-shaped weak polyelectrolyte in a thin film.

PubMed

Mu, Dan; Li, Jian-Quan; Feng, Sheng-Yu

2017-11-29

Different from the self-assembly of neutral polymers, polyelectrolytes self-assemble into smaller aggregates with a more loosely assembled structure, which results from the repulsive forces acting between similar electrical compositions with the introduction of ions. The Y-shaped weak polyelectrolytes self-assemble into a core-shell type cylindrical structure with a hexagonal arrangement in a thin film, whose thickness is smaller than the gyration radius of the polymer chain. The corresponding formation mechanism consists of enrichment of the same components, adjustment of the shape of the aggregate, and the subsequent separation into individual aggregates. With the increase in the thickness of the thin film until it exceeds the gyration radius of the polymer chain, combined with the greater freedom of movement along the direction of thin film thickness, the self-assembled structure changes into a micellar structure. Under confinement, the repulsive force to the polymeric components is weakened by the repulsive forces among polyelectrolyte components with like charges, and this helps in generating aggregates with more uniform size and density distribution. In particular, when the repulsive force between the walls and the core forming components is greater than that between the walls and the shell forming components, such asymmetric confinement produces a crossed-cylindrical structure with nearly perpendicular arrangement of two cylinder arrays. Similarly, a novel three-crossed cylinder morphology is self-assembled upon removal of confinement.

On the relationship between gingival biotypes and supracrestal gingival height, crown form and papilla height.

PubMed

Fischer, Kai R; Grill, Eva; Jockel-Schneider, Yvonne; Bechtold, Markus; Schlagenhauf, Ulrich; Fickl, Stefan

2014-08-01

To determine the association between gingival biotypes and supracrestal gingival height (primary aim) and its relation to crown shape and papilla height (secondary aim). Eighty adult subjects were evaluated in this study. Based on the transparency of a periodontal probe through the buccal gingival margin, 38 subjects comprised the thin biotype group and 42 subjects comprised the thick biotype group, respectively. Three different parameters were clinically assessed: supracrestal gingival height (SGH) by bone sounding, crown width/crown length ratio and papilla height. No statistical difference (P > 0.05) was detected neither for the correlation between different biotypes (thick/thin) and SGH nor for the association of biotypes and crown width/crown length ratio. Papilla height was only significantly increased (P ≤ 0.05) in the area of teeth no. 21/22 for the thin periodontal biotype. Intra-examiner deviation was found to be very low for all clinical parameters (percentile agreement > 95%). Within the limits of this study, we found that in young Caucasians (i) soft tissue dimensions seem to be similar between biotypes (ii) and the traditional hypothesis that a thick gingiva merges with broad-short crown shape and flat papillae and a thin gingiva with a narrow-long crown shape and high scalloping, may be questionable. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Flying mirror model for interaction of a super-intense laser pulse with a thin plasma layer: Transparency and shaping of linearly polarized laser pulses

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

Kulagin, Victor V.; Cherepenin, Vladimir A.; Hur, Min Sup

2007-11-15

A self-consistent one-dimensional (1D) flying mirror model is developed for description of an interaction of an ultra-intense laser pulse with a thin plasma layer (foil). In this model, electrons of the foil can have large longitudinal displacements and relativistic longitudinal momenta. An approximate analytical solution for a transmitted field is derived. Transmittance of the foil shows not only a nonlinear dependence on the amplitude of the incident laser pulse, but also time dependence and shape dependence in the high-transparency regime. The results are compared with particle-in-cell (PIC) simulations and a good agreement is ascertained. Shaping of incident laser pulses usingmore » the flying mirror model is also considered. It can be used either for removing a prepulse or for reducing the length of a short laser pulse. The parameters of the system for effective shaping are specified. Predictions of the flying mirror model for shaping are compared with the 1D PIC simulations, showing good agreement.« less

Reciprocal-space mapping of epitaxic thin films with crystallite size and shape polydispersity.

PubMed

Boulle, A; Conchon, F; Guinebretière, R

2006-01-01

A development is presented that allows the simulation of reciprocal-space maps (RSMs) of epitaxic thin films exhibiting fluctuations in the size and shape of the crystalline domains over which diffraction is coherent (crystallites). Three different crystallite shapes are studied, namely parallelepipeds, trigonal prisms and hexagonal prisms. For each shape, two cases are considered. Firstly, the overall size is allowed to vary but with a fixed thickness/width ratio. Secondly, the thickness and width are allowed to vary independently. The calculations are performed assuming three different size probability density functions: the normal distribution, the lognormal distribution and a general histogram distribution. In all cases considered, the computation of the RSM only requires a two-dimensional Fourier integral and the integrand has a simple analytical expression, i.e. there is no significant increase in computing times by taking size and shape fluctuations into account. The approach presented is compatible with most lattice disorder models (dislocations, inclusions, mosaicity, ...) and allows a straightforward account of the instrumental resolution. The applicability of the model is illustrated with the case of an yttria-stabilized zirconia film grown on sapphire.

Chincup treatment modifies the mandibular shape in children with prognathism.

PubMed

Alarcón, José Antonio; Bastir, Markus; Rosas, Antonio; Molero, Julia

2011-07-01

Although chincups are the preferred treatment for growing children with mandibular prognathism, the mechanism by which chincups improve this condition remains unclear. The aim of this study was to use geometric morphometrics to evaluate changes in the shape of the mandible of prognathic children treated with a chincup. Geometric morphometrics were used to evaluate the short-term mandibular shape changes in 50 prognathic children treated with chincups compared with 40 untreated matched controls. Twenty-one 2-dimensional mandibular landmarks from cephalograms taken before and after 36 months of treatment or observation were analyzed by Procrustes superimposition and thin plate spline. Permutation tests of the treated patients showed highly significant differences in the mandibular shapes before and after treatment, and compared with the control group after the observation period. The thin plate spline grid deformations indicated more rectangular mandibular configuration, forward condyle orientation, condyle neck compression, gonial area compression, and symphysis narrowing. Early chincup treatment widely modifies the mandibular shape of prognathic children to improve Class III malocclusion. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Damage localization by statistical evaluation of signal-processed mode shapes

NASA Astrophysics Data System (ADS)

Ulriksen, M. D.; Damkilde, L.

2015-07-01

Due to their inherent, ability to provide structural information on a local level, mode shapes and t.lieir derivatives are utilized extensively for structural damage identification. Typically, more or less advanced mathematical methods are implemented to identify damage-induced discontinuities in the spatial mode shape signals, hereby potentially facilitating damage detection and/or localization. However, by being based on distinguishing damage-induced discontinuities from other signal irregularities, an intrinsic deficiency in these methods is the high sensitivity towards measurement, noise. The present, article introduces a damage localization method which, compared to the conventional mode shape-based methods, has greatly enhanced robustness towards measurement, noise. The method is based on signal processing of spatial mode shapes by means of continuous wavelet, transformation (CWT) and subsequent, application of a generalized discrete Teager-Kaiser energy operator (GDTKEO) to identify damage-induced mode shape discontinuities. In order to evaluate whether the identified discontinuities are in fact, damage-induced, outlier analysis of principal components of the signal-processed mode shapes is conducted on the basis of T2-statistics. The proposed method is demonstrated in the context, of analytical work with a free-vibrating Euler-Bernoulli beam under noisy conditions.

Identification of facial shape by applying golden ratio to the facial measurements: an interracial study in malaysian population.

PubMed

Packiriswamy, Vasanthakumar; Kumar, Pramod; Rao, Mohandas

2012-12-01

The "golden ratio" is considered as a universal facial aesthetical standard. Researcher's opinion that deviation from golden ratio can result in development of facial abnormalities. This study was designed to study the facial morphology and to identify individuals with normal, short, and long face. We studied 300 Malaysian nationality subjects aged 18-28 years of Chinese, Indian, and Malay extraction. The parameters measured were physiognomical facial height and width of face, and physiognomical facial index was calculated. Face shape was classified based on golden ratio. Independent t test was done to test the difference between sexes and among the races. The mean values of the measurements and index showed significant sexual and interracial differences. Out of 300 subjects, the face shape was normal in 60 subjects, short in 224 subjects, and long in 16 subjects. As anticipated, the measurements showed variations according to gender and race. Only 60 subjects had a regular face shape, and remaining 240 subjects had irregular face shape (short and long). Since the short and long shape individuals may be at risk of developing various disorders, the knowledge of facial shapes in the given population is important for early diagnostic and treatment procedures.

Sealing Penetrating Eye Injuries Using Photoactivated Bonding

DTIC Science & Technology

2012-09-01

membrane over a penetrating corneal injury with photochemical tissue bonding ( PTB )(Task 1), we had proposed to directly bond, with PTB , the edges of...wounds with irregular shapes which mimic traumatic wounds. We had previously demonstrated that PTB effectively sealed linear incisional wounds in...developed for sealing eyelid lacerations with PTB was submitted in Year 2 and was published in Year 3 in Lasers in Surgery and Medicine. It is listed in

Implementation Plan for Flexible Automation in U.S. Shipyards

DTIC Science & Technology

1985-01-01

process steps, cramped work sites, interrupted geometries , irregular or novel shapes, and other factors that affect automatability. We also try to...held by 2 hands in awkward places. Interrupt geometry of plates and beams. Cannot predict outcome. Creates need to measure and recut. Automation, if...of standard. enough over time I every job. I Rearrange work.Redefine work units. Too many interruptions Time, space, geometry only a little work gets

Coupling Inductor Based Hybrid Millimeter-Wave Switch

NASA Technical Reports Server (NTRS)

Gu, Qun (Inventor); Drouin, Brian J. (Inventor); Tang, Adrian J. (Inventor); Shu, Ran (Inventor)

2017-01-01

A switch comprising a plurality of inductors and a plurality of shunt transistors is described. Each inductor can be electrically coupled between adjacent shunt transistors to form a distributed switch structure. At least two inductors in the plurality of inductors can be inductively coupled with each other. The plurality of inductors can correspond to portions of a coupling inductor, wherein the coupling inductor can have an irregular octagonal shape.

Pulsed source ion implantation apparatus and method

DOEpatents

Leung, K.N.

1996-09-24

A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted. 16 figs.

Digital micromirror device as programmable rough particle in interferometric particle imaging.

PubMed

Fromager, M; Aït Ameur, K; Brunel, M

2017-04-20

The 2D autocorrelation of the projection of an irregular rough particle can be estimated using the analysis of its interferometric out-of-focus image. We report the development of an experimental setup that creates speckle-like patterns generated by "programmable" rough particles of desired-shape. It should become an important tool for the development of new setups, configurations, and algorithms in interferometric particle imaging.

Method of casting aerogels

DOEpatents

Poco, J.F.

1993-09-07

The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.

General George Crooks Development as a Practitioner of Irregular Warfare During the Indian Wars

DTIC Science & Technology

2017-06-09

dogged determination, this cemented Crook’s understanding of the Indian problem, which would help shape the burgeoning American west...General Frederick Steele took command of the Department of the Columbia in early 1866 and shortly thereafter established Boise as its own district...regaining control of the area would be difficult, General Steele requested and received reinforcements. He received three additional companies of

Graphical Acoustic Liner Design and Analysis Tool

NASA Technical Reports Server (NTRS)

Howerton, Brian M. (Inventor); Jones, Michael G. (Inventor)

2016-01-01

An interactive liner design and impedance modeling tool comprises software utilized to design acoustic liners for use in constrained spaces, both regularly and irregularly shaped. A graphical user interface allows the acoustic channel geometry to be drawn in a liner volume while the surface impedance calculations are updated and displayed in real-time. A one-dimensional transmission line model may be used as the basis for the impedance calculations.

Use of a spread sheet to calculate the current-density distribution produced in human and rat models by low-frequency electric fields.

PubMed

Hart, F X

1990-01-01

The current-density distribution produced inside irregularly shaped, homogeneous human and rat models by low-frequency electric fields is obtained by a two-stage finite-difference procedure. In the first stage the model is assumed to be equipotential. Laplace's equation is solved by iteration in the external region to obtain the capacitive-current densities at the model's surface elements. These values then provide the boundary conditions for the second-stage relaxation solution, which yields the internal current-density distribution. Calculations were performed with the Excel spread-sheet program on a Macintosh-II microcomputer. A spread sheet is a two-dimensional array of cells. Each cell of the sheet can represent a square element of space. Equations relating the values of the cells can represent the relationships between the potentials in the corresponding spatial elements. Extension to three dimensions is readily made. Good agreement was obtained with current densities measured on human models with both, one, or no legs grounded and on rat models in four different grounding configurations. The results also compared well with predictions of more sophisticated numerical analyses. Spread sheets can provide an inexpensive and relatively simple means to perform good, approximate dosimetric calculations on irregularly shaped objects.

A hydrodynamic model of an outer hair cell

NASA Technical Reports Server (NTRS)

Jacobson, B. O.

1982-01-01

On the model it is possible to measure the force and the force direction for each individual hair as a function of the flow direction and velocity. Measurements were made at the man flow velocity .01 m/s, which is equivalent to a flow velocity in the real ear of about 1 micrometer/s. The kinematic viscosity of the liquid used in the model was 10,000 times higher than the viscosity of perilymph to attain hydrodynamic equality. Two different geometries for the sterocilia pattern were tested. First the force distribution for a W-shaped sterocilia pattern was recorded. This is the sterocilia pattern found in all real ears. It is found that the forces acting on the hairs are very regular and perpendicular to the legs of the W when the flow is directed from the outside of the W. When the flow is reversed, the forces are not reversed, but are much more irregular. This can eventually explain the half wave rectification of the nerve signals. As a second experiment, the force distribution for a V-shaped sterocilia pattern was recorded. Here the forces were irregular both when the flow was directed into the V and when it was directed against the edge of the V.

Clinical implementation of stereotaxic brain implant optimization

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

Rosenow, U.F.; Wojcicka, J.B.

1991-03-01

This optimization method for stereotaxic brain implants is based on seed/strand configurations of the basic type developed for the National Cancer Institute (NCI) atlas of regular brain implants. Irregular target volume shapes are determined from delineation in a stack of contrast enhanced computed tomography scans. The neurosurgeon may then select up to ten directions, or entry points, of surgical approach of which the program finds the optimal one under the criterion of smallest target volume diameter. Target volume cross sections are then reconstructed in 5-mm-spaced planes perpendicular to the implantation direction defined by the entry point and the target volumemore » center. This information is used to define a closed line in an implant cross section along which peripheral seed strands are positioned and which has now an irregular shape. Optimization points are defined opposite peripheral seeds on the target volume surface to which the treatment dose rate is prescribed. Three different optimization algorithms are available: linear least-squares programming, quadratic programming with constraints, and a simplex method. The optimization routine is implemented into a commercial treatment planning system. It generates coordinate and source strength information of the optimized seed configurations for further dose rate distribution calculation with the treatment planning system, and also the coordinate settings for the stereotaxic Brown-Roberts-Wells (BRW) implantation device.« less

Effects of the phosphatase inhibitors, okadaic acid, ATPgammaS, and calyculin A on the dividing sand dollar egg.

PubMed

Hamaguchi, Yukihisa; Kuriyama, Ryoko

2002-06-01

The effects of the phosphatase inhibitors, okadaic acid (OA), adenosine 5'-O-(3-thiotriphosphate) (ATPgammaS), and calyculin A (CL-A) on anaphase chromosome movement, cytokinesis, and cytoskeletal structures at cell division were examined by being microinjected into mitotic sand dollar eggs. When OA was injected, chromosome movement was inhibited and, moreover, chromosomes were ejected from the polar regions of the mitotic apparatus. By immunofluorescence, microtubules were observed to be severed in the OA-injected eggs, causing the smooth cell surface to be changed to an irregular surface. When ATPgammaS and CL-A were injected, the effect on cell shape was remarkable: In dividing eggs, furrowing stopped within several seconds after injection, small blebs appeared on the cell surface and became large, spherical or dumbbell cell shapes then changed to irregular forms, and subsequently cytoplasmic flow occurred. Microfilament detection revealed that actin accumulation in the cortex, which was not limited to the furrow cortex, occurred shortly after injection. Cortical accumulation of actin is thought to induce force generation and random cortical contraction, and accordingly to result in bleb extrusion from the cortex. Consequently, the phosphatase inhibitors inhibited the transition from mitosis to interphase by mediating cortical accumulation of actin filaments and/or fragmentation of microtubules.