Ulnar nerve dysfunction

Science.gov (United States)

Neuropathy - ulnar nerve; Ulnar nerve palsy; Mononeuropathy; Cubital tunnel syndrome ... Damage to one nerve group, such as the ulnar nerve, is called mononeuropathy . Mononeuropathy means there is damage to a single nerve. Both ...

Effects of forefoot bending stiffness of badminton shoes on agility, comfort perception and lower leg kinematics during typical badminton movements.

Science.gov (United States)

Park, Sang-Kyoon; Lam, Wing-Kai; Yoon, Sukhoon; Lee, Ki-Kwang; Ryu, Jiseon

2017-09-01

This study investigated whether an increase in the forefoot bending stiffness of a badminton shoe would positively affect agility, comfort and biomechanical variables during badminton-specific movements. Three shoe conditions with identical shoe upper and sole designs with different bending stiffness (Flexible, Regular and Stiff) were used. Elite male badminton players completed an agility test on a standard badminton court involving consecutive lunges in six directions, a comfort test performed by a pair of participants conducting a game-like practice trial and a biomechanics test involving a random assignment of consecutive right forward lunges. No significant differences were found in agility time and biomechanical variables among the three shoes. The players wearing the shoe with a flexible forefoot outsole demonstrated a decreased perception of comfort in the forefoot cushion compared to regular and stiffer conditions during the comfort test (p badminton-specific tasks. It was concluded that an optimisation of forefoot structure and materials in badminton shoes should consider the individual's perception to maximise footwear comfort in performance.

Effect of web stiffness on the bending behaviour of timber composite I-beams

International Nuclear Information System (INIS)

Racher, P.; Bocquet, J.F.; Bouchair, A.

2007-01-01

The design of timber I-beams with glued OSB web is currently based on simplified analytical model and experimental works. At the ultimate limit state, normal forces in the flanges and shear stresses in the web govern the load-carrying capacity of the beams. Applications in industrial or commercial buildings requires cross-section with greater height. In this paper, the effect of the slenderness of the web is analysed through an experimental program and a finite element model. For beams with finger-jointed flanges and butt-joints between web panels, the effective stiffness and the bending capacity are evaluated considering a web of 12 mm in thickness and height varying from 225 to 495 mm. The experimental values of the effective stiffness were compared to the theoretical evaluation taking into account the shear deformations of the web. For highest heights of the cross-section, the results shown that the ultimate capacity is governed by the plate behaviour of the web, resulting in the failure of the glued joint. On this basis, the internal behaviour is examined using a three-dimensional finite element modelling. The effect of the mains parameters such as the relative stiffness of the components and the gap between web panels is investigated. The stress concentration in the area of the web joint is analysed and a new design criterion is calibrated

Effect of web stiffness on the bending behaviour of timber composite I-beams

Energy Technology Data Exchange (ETDEWEB)

Racher, P. [Civil Engineering Laboratory, CUST, Blaise Pascal University - Campus des Cezeaux, BP 206, 63174 Aubiere Cedex (France)]. E-mail: p.racher@cust.univ-bpclermont.fr; Bocquet, J.F. [LERMAB, ENSTIB, Henri Poincarre University, 88000 Epinal (France); Bouchair, A. [Civil Engineering Laboratory, CUST, Blaise Pascal University - Campus des Cezeaux, BP 206, 63174 Aubiere Cedex (France)

2007-07-01

The design of timber I-beams with glued OSB web is currently based on simplified analytical model and experimental works. At the ultimate limit state, normal forces in the flanges and shear stresses in the web govern the load-carrying capacity of the beams. Applications in industrial or commercial buildings requires cross-section with greater height. In this paper, the effect of the slenderness of the web is analysed through an experimental program and a finite element model. For beams with finger-jointed flanges and butt-joints between web panels, the effective stiffness and the bending capacity are evaluated considering a web of 12 mm in thickness and height varying from 225 to 495 mm. The experimental values of the effective stiffness were compared to the theoretical evaluation taking into account the shear deformations of the web. For highest heights of the cross-section, the results shown that the ultimate capacity is governed by the plate behaviour of the web, resulting in the failure of the glued joint. On this basis, the internal behaviour is examined using a three-dimensional finite element modelling. The effect of the mains parameters such as the relative stiffness of the components and the gap between web panels is investigated. The stress concentration in the area of the web joint is analysed and a new design criterion is calibrated.

Traumatic Distal Ulnar Artery Thrombosis

Directory of Open Access Journals (Sweden)

Ahmet A. Karaarslan

2014-01-01

Full Text Available This paper is about a posttraumatic distal ulnar artery thrombosis case that has occurred after a single blunt trauma. The ulnar artery thrombosis because of chronic trauma is a frequent condition (hypothenar hammer syndrome but an ulnar artery thrombosis because of a single direct blunt trauma is rare. Our patient who has been affected by a single blunt trauma to his hand and developed ulnar artery thrombosis has been treated by resection of the thrombosed ulnar artery segment. This report shows that a single blunt trauma can cause distal ulnar artery thrombosis in the hand and it can be treated merely by thrombosed segment resection in suitable cases.

Artificial muscles with adjustable stiffness

International Nuclear Information System (INIS)

Mutlu, Rahim; Alici, Gursel

2010-01-01

This paper reports on a stiffness enhancement methodology based on using a suitably designed contact surface with which cantilevered-type conducting polymer bending actuators are in contact during operation. The contact surface constrains the bending behaviour of the actuators. Depending on the topology of the contact surface, the resistance of the polymer actuators to deformation, i.e. stiffness, is varied. As opposed to their predecessors, these polymer actuators operate in air. Finite element analysis and modelling are used to quantify the effect of the contact surface on the effective stiffness of a trilayer cantilevered beam, which represents a one-end-free, the-other-end-fixed polypyrrole (PPy) conducting polymer actuator under a uniformly distributed load. After demonstrating the feasibility of the adjustable stiffness concept, experiments were conducted to determine the stiffness of bending-type conducting polymer actuators in contact with a range (20–40 mm in radius) of circular contact surfaces. The numerical and experimental results presented demonstrate that the stiffness of the actuators can be varied using a suitably profiled contact surface. The larger the radius of the contact surface is, the higher is the stiffness of the polymer actuators. The outcomes of this study suggest that, although the stiffness of the artificial muscles considered in this study is constant for a given geometric size, and electrical and chemical operation conditions, it can be changed in a nonlinear fashion to suit the stiffness requirement of a considered application. The stiffness enhancement methodology can be extended to other ionic-type conducting polymer actuators

Development of a stiffness-angle law for simplifying the measurement of human hair stiffness.

Science.gov (United States)

Jung, I K; Park, S C; Lee, Y R; Bin, S A; Hong, Y D; Eun, D; Lee, J H; Roh, Y S; Kim, B M

2018-04-01

This research examines the benefits of caffeine absorption on hair stiffness. To test hair stiffness, we have developed an evaluation method that is not only accurate, but also inexpensive. Our evaluation method for measuring hair stiffness culminated in a model, called the Stiffness-Angle Law, which describes the elastic properties of hair and can be widely applied to the development of hair care products. Small molecules (≤500 g mol -1 ) such as caffeine can be absorbed into hair. A common shampoo containing 4% caffeine was formulated and applied to hair 10 times, after which the hair stiffness was measured. The caffeine absorption of the treated hair was observed using Fourier-transform infrared spectroscopy (FTIR) with a focal plane array (FPA) detector. Our evaluation method for measuring hair stiffness consists of a regular camera and a support for single strands of hair. After attaching the hair to the support, the bending angle of the hair was observed with a camera and measured. Then, the hair strand was weighed. The stiffness of the hair was calculated based on our proposed Stiffness-Angle Law using three variables: angle, weight of hair and the distance the hair was pulled across the support. The caffeine absorption was confirmed by FTIR analysis. The concentration of amide bond in the hair certainly increased due to caffeine absorption. After caffeine was absorbed into the hair, the bending angle and weight of the hair changed. Applying these measured changes to the Stiffness-Angle Law, it was confirmed that the hair stiffness increased by 13.2% due to caffeine absorption. The theoretical results using the Stiffness-Angle Law agree with the visual examinations of hair exposed to caffeine and also the known results of hair stiffness from a previous report. Our evaluation method combined with our proposed Stiffness-Angle Law effectively provides an accurate and inexpensive evaluation technique for measuring bending stiffness of human hair. © 2018

Stiffness requirement of flexible skin for variable trailing-edge camber wing

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

The method for analyzing the deformation of flexible skin under the air loads was developed based on the panel method and finite element method.The deformation of flexible skin under air pressures and effects of the local deformation on the aerodynamic characteristics were discussed.Numerical results show that the flexible skin on the upper surface of trailing-edge will bubble under the air loads and the bubble has a powerful effect on the aerodynamic pressure near the surface of local deforma-tion.Then the stiffness requirements for flexible skin of variable trailing-edge were given by using the Jacobs rule,i.e.,the maximum displacement of skin is not greater than 0.1% of wing chord.Results show that the in-plane stiffness can be reduced by increasing the ratio of bending stiffness to in-plane stiffness.Although the deformation of flexible skin increases with the in-plane stiffness decreasing,it depends on the bending stiffness.When the bending stiffness exceeds critical value,the deformation of flexible skin only depends on the bending stiffness and has nothing to do with the in-plane stiffness.The conclusions can be used for the structural design of flexible skin.

Ulnar nerve damage (image)

Science.gov (United States)

The ulnar nerve originates from the brachial plexus and travels down arm. The nerve is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near the surface of the body where ...

A novel variable stiffness mechanism for dielectric elastomer actuators

Science.gov (United States)

Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang

2017-08-01

In this paper, a novel variable stiffness mechanism is proposed for the design of a variable stiffness dielectric elastomer actuator (VSDEA) which combines a flexible strip with a DEA in a dielectric elastomer minimum energy structure. The DEA induces an analog tuning of the transverse curvature of the strip, thus conveniently providing a voltage-controllable flexural rigidity. The VSDEA tends to be a fully flexible and compact structure with the advantages of simplicity and fast response. Both experimental and theoretical investigations are carried out to reveal the variable stiffness performances of the VSDEA. The effect of the clamped location on the bending stiffness of the VSDEA is analyzed, and then effects of the lengths, the loading points and the applied voltages on the bending stiffness are experimentally investigated. An analytical model is developed to verify the availability of this variable stiffness mechanism, and the theoretical results demonstrate that the bending stiffness of the VSDEA decreases as the applied voltage increases, which agree well with the experimental data. Moreover, the experimental results show that the maximum change of the relative stiffness can reach about 88.80%. It can be useful for the design and optimization of active variable stiffness structures and DEAs for soft robots, vibration control, and morphing applications.

Evaluation of spinal instrumentation rod bending characteristics for in-situ contouring.

Science.gov (United States)

Noshchenko, Andriy; Xianfeng, Yao; Armour, Grant Alan; Baldini, Todd; Patel, Vikas V; Ayers, Reed; Burger, Evalina

2011-07-01

Bending characteristics were studied in rods used for spinal instrumentation at in-situ contouring conditions. Five groups of five 6 mm diameter rods made from: cobalt alloy (VITALLIUM), titanium-aluminum-vanadium alloy (SDI™), β-titanium alloy (TNTZ), cold worked stainless steel (STIFF), and annealed stainless steel (MALLEABLE) were studied. The bending procedure was similar to that typically applied for in-situ contouring in the operating room and included two bending cycles: first--bending to 21-24° under load with further release of loading for 10 min, and second--bending to 34-37° at the previously bent site and release of load for 10 min. Applied load, bending stiffness, and springback effect were studied. Statistical evaluation included ANOVA, correlation and regression analysis. TNTZ and SDI™ rods showed the highest (p under load (p < 0.001). To reach the necessary bend angle after unloading, over bending should be 37-40% of the required angle in TNTZ and SDI™ rods, 27-30% in VITALLIUM and STIFF rods, and around 20% in MALLEABLE rods. Copyright © 2011 Wiley Periodicals, Inc.

Ulnar Collateral Ligament Injuries of the Thumb

Science.gov (United States)

McKeon, Kathleen E.; Gelberman, Richard H.; Calfee, Ryan P.

2013-01-01

Background: The clinical diagnosis of thumb ulnar collateral ligament disruption has been based on joint angulation during valgus stress testing. This report describes a definitive method of distinguishing between complete and partial ulnar collateral ligament injuries by quantifying translation of the proximal phalanx on the metacarpal head during valgus stress testing. Methods: Sixty-two cadaveric thumbs underwent standardized valgus stress testing under fluoroscopy with the ulnar collateral ligament intact, following an isolated release of the proper ulnar collateral ligament, and following a combined release of both the proper and the accessory ulnar collateral ligament (complete ulnar collateral ligament release). Following complete ulnar collateral ligament release, the final thirty-seven thumbs were also analyzed after the application of a valgus force sufficient to cause 45° of valgus angulation at the metacarpophalangeal joint to model more severe soft-tissue injury. Two independent reviewers measured coronal plane joint angulation (in degrees), ulnar joint line gap formation (in millimeters), and radial translation of the proximal phalanx on the metacarpal head (in millimeters) on digital fluoroscopic images that had been randomized. Results: Coronal angulation across the stressed metacarpophalangeal joint progressively increased through the stages of the testing protocol: ulnar collateral ligament intact (average [and standard deviation], 20° ± 8.1°), release of the proper ulnar collateral ligament (average, 23° ± 8.3°), and complete ulnar collateral ligament release (average, 30° ± 8.9°) (p collateral ligament release (5.7 ± 1.5 mm), to that following complete ulnar collateral ligament release (7.2 ± 1.5 mm) (p collateral ligament (1.6 ± 0.8 mm vs. 1.5 ± 0.9 mm in the intact state). There was a significant increase in translation following release of the complete ulnar collateral ligament complex (3.0 ± 0.9 mm; p collateral ligament

Biomechanical properties of orthogonal plate configuration versus parallel plate configuration using the same locking plate system for intra-articular distal humeral fractures under radial or ulnar column axial load.

Science.gov (United States)

Kudo, Toshiya; Hara, Akira; Iwase, Hideaki; Ichihara, Satoshi; Nagao, Masashi; Maruyama, Yuichiro; Kaneko, Kazuo

2016-10-01

Previous reports have questioned whether an orthogonal or parallel configuration is superior for distal humeral articular fractures. In previous clinical and biomechanical studies, implant failure of the posterolateral plate has been reported with orthogonal configurations; however, the reason for screw loosening in the posterolateral plate is unclear. The purpose of this study was to evaluate biomechanical properties and to clarify the causes of posterolateral plate loosening using a humeral fracture model under axial compression on the radial or ulnar column separately. And we changed only the plate set up: parallel or orthogonal. We used artificial bone to create an Association for the Study of Internal Fixation type 13-C2.3 intra-articular fracture model with a 1-cm supracondylar gap. We used an anatomically-preshaped distal humerus locking compression plate system (Synthes GmbH, Solothurn, Switzerland). Although this is originally an orthogonal plate system, we designed a mediolateral parallel configuration to use the contralateral medial plate instead of the posterolateral plate in the system. We calculated the stiffness of the radial and ulnar columns and anterior movement of the condylar fragment in the lateral view. The parallel configuration was superior to the orthogonal configuration regarding the stiffness of the radial column axial compression. There were significant differences between the two configurations regarding anterior movement of the capitellum during axial loading of the radial column. The posterolateral plate tended to bend anteriorly under axial compression compared with the medial or lateral plate. We believe that in the orthogonal configuration axial compression induced more anterior displacement of the capitellum than the trochlea, which eventually induced secondary fragment or screw dislocation on the posterolateral plate, or nonunion at the supracondylar level. In the parallel configuration, anterior movement of the capitellum or

A radiographic study of pediatric ulnar anatomy.

Science.gov (United States)

Cravino, Mattia; Oni, Julius K; Sala, Debra A; Chu, Alice

2014-01-01

The adult ulna has a unique bony architecture that has been described in the literature, but, to the best of our knowledge, the ulnar anatomy in children has not been described. We examined 75 anteroposterior (AP) and 64 lateral radiographs (29 were bilateral) of 50, 0.5- to 11-year-old, healthy children's forearms. On AP radiographs, the total ulnar length, the ulnar proximal angle, the ulnar distal angle, and the distance between each angle from the tip of the triceps insertion; and, on lateral radiographs, the ulnar length and bow deviation were measured. The correlation between age and radiographic measurements, differences based on sex, differences compared with adults' measurements, and interobserver/intraobserver reliability were assessed. Age had a very strong/strong positive correlation with length/distance measurements on both AP and lateral radiographs. Only AP ulnar distal angle was significantly different between sexes (females > males). Compared with the adult ulnar studies, the AP proximal angle in children is significantly smaller and the location of this angle is significantly more distal. Interobserver and intraobserver reliability were very good for length/distance measurements on AP and lateral radiographs. The knowledge of pediatric ulnar anatomy could be helpful in the treatment of forearm deformities due to multiple hereditary exostosis and osteogenesis imperfecta, and in the treatment of ulnar fractures, particularly in Monteggia variants, where restoration of the correct forearm anatomy is essential to obtain good clinical and functional results. Study of diagnostic test, Level II.

The gearing function of running shoe longitudinal bending stiffness.

Science.gov (United States)

Willwacher, Steffen; König, Manuel; Braunstein, Björn; Goldmann, Jan-Peter; Brüggemann, Gert-Peter

2014-07-01

The purpose of the present study was to investigate whether altered longitudinal bending stiffness (LBS) levels of the midsole of a running shoe lead to a systematic change in lower extremity joint lever arms of the ground reaction force (GRF). Joint moments and GRF lever arms in the sagittal plane were determined from 19 male subjects running at 3.5 m/s using inverse dynamics procedures. LBS was manipulated using carbon fiber insoles of 1.9 mm and 3.2 mm thickness. Increasing LBS led to a significant shift of joint lever arms to a more anterior position. Effects were more pronounced at distal joints. Ankle joint moments were not significantly increased in the presence of higher GRF lever arms when averaged over all subjects. Still, two individual strategies (1: increase ankle joint moments while keeping push-off times almost constant, 2: decrease ankle joint moments and increase push-off times) could be identified in response to increased ankle joint lever arms that might reflect individual differences between subjects with respect to strength capacities or anthropometric characteristics. The results of the present study indicate that LBS systematically influences GRF lever arms of lower extremity joints during the push-off phase in running. Further, individual responses to altered LBS levels could be identified that could aid in finding optimum LBS values for a given individual. Copyright © 2014 Elsevier B.V. All rights reserved.

Role of flexural stiffness of leukocyte microvilli in adhesion dynamics

Science.gov (United States)

Wu, Tai-Hsien; Qi, Dewei

2018-03-01

Previous work reported that microvillus deformation has an important influence on dynamics of cell adhesion. However, the existing studies were limited to the extensional deformation of microvilli and did not consider the effects of their bending deformation on cell adhesion. This Rapid Communication investigates the effects of flexural stiffness of microvilli on the rolling process related to adhesion of leukocytes by using a lattice-Boltzmann lattice-spring method (LLM) combined with adhesive dynamics (AD) simulations. The simulation results reveal that the flexural stiffness of microvilli and their bending deformation have a profound effect on rolling velocity and adhesive forces. As the flexural stiffness of the microvilli decreases, their bending angles increase, resulting in an increase in the number of receptor-ligand bonds and adhesive bonding force and a decrease in the rolling velocity of leukocytes. The effects of flexural stiffness on deformation and adhesion represent crucial factors involved in cell adhesion.

Diagnosing ulnar neuropathy at the elbow using magnetic resonance neurography

International Nuclear Information System (INIS)

Keen, Nayela N.; Chin, Cynthia T.; Saloner, David; Steinbach, Lynne S.; Engstrom, John W.

2012-01-01

Early diagnosis of ulnar neuropathy at the elbow is important. Magnetic resonance neurography (MRN) images peripheral nerves. We evaluated the usefulness of elbow MRN in diagnosing ulnar neuropathy at the elbow. The MR neurograms of 21 patients with ulnar neuropathy were reviewed retrospectively. MRN was performed prospectively on 10 normal volunteers. The MR neurograms included axial T1 and axial T2 fat-saturated and/or axial STIR sequences. The sensitivity and specificity of MRN in detecting ulnar neuropathy were determined. The mean ulnar nerve size in the symptomatic and normal groups was 0.12 and 0.06 cm 2 (P 2 , sensitivity was 95% and specificity was 80%. Ulnar nerve size and signal intensity were greater in patients with ulnar neuropathy. MRN is a useful test in evaluating ulnar neuropathy at the elbow. (orig.)

Ulnar nerve sonography in leprosy neuropathy.

Science.gov (United States)

Wang, Zhu; Liu, Da-Yue; Lei, Yang-Yang; Yang, Zheng; Wang, Wei

2016-01-01

A 23-year-old woman presented with a half-year history of right forearm sensory and motor dysfunction. Ultrasound imaging revealed definite thickening of the right ulnar nerve trunk and inner epineurium, along with heterogeneous hypoechogenicity and unclear nerve fiber bundle. Color Doppler exhibited a rich blood supply, which was clearly different from the normal ulnar nerve presentation with a scarce blood supply. The patient subsequently underwent needle aspiration of the right ulnar nerve, and histopathological examination confirmed that granulomatous nodules had formed with a large number of infiltrating lymphocytes and a plurality of epithelioid cells in the fibrous connective tissues, with visible atypical foam cells and proliferous vascularization, consistent with leprosy. Our report will familiarize readers with the characteristic sonographic features of the ulnar nerve in leprosy, particularly because of the decreasing incidence of leprosy in recent years.

Mass and stiffness calibration of nanowires using thermally driven vibration

International Nuclear Information System (INIS)

Kiracofe, D R; Raman, A; Yazdanpanah, M M

2011-01-01

Cantilevered or suspended nanowires show promise for force or mass sensing applications due to their small mass, high force sensitivity and high frequency bandwidth. To use these as quantitative sensors, their bending stiffness or mass must be calibrated experimentally, often using thermally driven vibration. However, this can be difficult because nanowires are slightly asymmetric, which results in two spatially orthogonal bending eigenmodes with closely spaced frequencies. This asymmetry presents problems for traditional stiffness calibration methods, which equate the measured thermal vibration spectrum near a resonance to that of a single eigenmode. Moreover, the principal axes may be arbitrarily rotated with respect to the measurement direction. In this work, the authors propose a method for calibrating the bending stiffness and mass of such nanowires' eigenmodes using a single measurement taken at an arbitrary orientation with respect to the principal axes.

Diagnosing ulnar neuropathy at the elbow using magnetic resonance neurography

Energy Technology Data Exchange (ETDEWEB)

Keen, Nayela N.; Chin, Cynthia T.; Saloner, David; Steinbach, Lynne S. [University of California San Francisco, Dept of Radiology and Biomedical Imaging, San Francisco, CA (United States); Engstrom, John W. [University of California San Francisco, Department of Neurology, San Francisco, CA (United States)

2012-04-15

Early diagnosis of ulnar neuropathy at the elbow is important. Magnetic resonance neurography (MRN) images peripheral nerves. We evaluated the usefulness of elbow MRN in diagnosing ulnar neuropathy at the elbow. The MR neurograms of 21 patients with ulnar neuropathy were reviewed retrospectively. MRN was performed prospectively on 10 normal volunteers. The MR neurograms included axial T1 and axial T2 fat-saturated and/or axial STIR sequences. The sensitivity and specificity of MRN in detecting ulnar neuropathy were determined. The mean ulnar nerve size in the symptomatic and normal groups was 0.12 and 0.06 cm{sup 2} (P < 0.001). The mean relative signal intensity in the symptomatic and normal groups was 2.7 and 1.4 (P < 0.01). When using a size of 0.08 cm{sup 2}, sensitivity was 95% and specificity was 80%. Ulnar nerve size and signal intensity were greater in patients with ulnar neuropathy. MRN is a useful test in evaluating ulnar neuropathy at the elbow. (orig.)

Ulnar nerve injury associated with trampoline injuries.

Science.gov (United States)

Maclin, Melvin M; Novak, Christine B; Mackinnon, Susan E

2004-08-01

This study reports three cases of ulnar neuropathy after trampoline injuries in children. A chart review was performed on children who sustained an ulnar nerve injury from a trampoline accident. In all cases, surgical intervention was required. Injuries included upper-extremity fractures in two cases and an upper-extremity laceration in one case. All cases required surgical exploration with internal neurolysis and ulnar nerve transposition. Nerve grafts were used in two cases and an additional nerve transfer was used in one case. All patients had return of intrinsic hand function and sensation after surgery. Children should be followed for evolution of ulnar nerve neuropathy after upper-extremity injury with consideration for electrical studies and surgical exploration if there is no improvement after 3 months.

Bending stresses in Facetted Glass Shells

DEFF Research Database (Denmark)

Bagger, Anne; Jönsson, Jeppe; Almegaard, Henrik

2008-01-01

A shell structure of glass combines a highly effective structural principle with a material of optimal permeability to light. A facetted shell structure has a piecewise plane geometry, and together the facets form an approximation to a curved surface. A distributed load on a plane-based facetted...... structure will locally cause bending moments in the loaded facets. The bending stresses are dependent on the stiffness of the joints. Approximate solutions are developed to estimate the magnitude of the bending stresses. A FE-model of a facetted glass shell structure is used to validate the expressions...

Anomalies of radial and ulnar arteries

Directory of Open Access Journals (Sweden)

Rajani Singh

Full Text Available Abstract During dissection conducted in an anatomy department of the right upper limb of the cadaver of a 70-year-old male, both origin and course of the radial and ulnar arteries were found to be anomalous. After descending 5.5 cm from the lower border of the teres major, the brachial artery anomalously bifurcated into a radial artery medially and an ulnar artery laterally. In the arm, the ulnar artery lay lateral to the median nerve. It followed a normal course in the forearm. The radial artery was medial to the median nerve in the arm and then, at the level of the medial epicondyle, it crossed from the medial to the lateral side of the forearm, superficial to the flexor muscles. The course of the radial artery was superficial and tortuous throughout the arm and forearm. The variations of radial and ulnar arteries described above were associated with anomalous formation and course of the median nerve in the arm. Knowledge of neurovascular anomalies are important for vascular surgeons and radiologists.

A Comparison of Ulnar Shortening Osteotomy Alone Versus Combined Arthroscopic Triangular Fibrocartilage Complex Debridement and Ulnar Shortening Osteotomy for Ulnar Impaction Syndrome

Science.gov (United States)

Song, Hyun Seok

2011-01-01

Background This study compared the results of patients treated for ulnar impaction syndrome using an ulnar shortening osteotomy (USO) alone with those treated with combined arthroscopic debridement and USO. Methods The results of 27 wrists were reviewed retrospectively. They were divided into three groups: group A (USO alone, 10 cases), group B (combined arthroscopic debridement and USO, 9 cases), and group C (arthroscopic triangular fibrocartilage complex [TFCC] debridement alone, 8 cases). The wrist function was evaluated using the modified Mayo wrist score, disabilities of the arm, shoulder and hand (DASH) score and Chun and Palmer grading system. Results The modified Mayo wrist score in groups A, B, and C was 74.5 ± 8.9, 73.9 ± 11.6, and 61.3 ± 10.2, respectively (p 0.05). Conclusions Both USO alone and combined arthroscopic TFCC debridement with USO improved the wrist function and reduced the level of pain in the patients treated for ulnar impaction syndrome. USO alone may be the preferred method of treatment in patients if the torn flap of TFCC is not unstable. PMID:21909465

Design and optimization of a bend-and-sweep compliant mechanism

International Nuclear Information System (INIS)

Tummala, Y; Frecker, M I; Wissa, A A; Hubbard Jr, J E

2013-01-01

A novel contact aided compliant mechanism called bend-and-sweep compliant mechanism is presented in this paper. This mechanism has nonlinear stiffness properties in two orthogonal directions. An angled compliant joint (ACJ) is the fundamental element of this mechanism. Geometric parameters of ACJs determine the stiffness of the compliant mechanism. This paper presents the design and optimization of bend-and-sweep compliant mechanism. A multi-objective optimization problem was formulated for design optimization of the bend-and-sweep compliant mechanism. The objectives of the optimization problem were to maximize or minimize the bending and sweep displacements, depending on the situation, while minimizing the von Mises stress and mass of each mechanism. This optimization problem was solved using NSGA-II (a genetic algorithm). The results of this optimization for a single ACJ during upstroke and downstroke are presented in this paper. Results of two different loading conditions used during optimization of a single ACJ for upstroke are presented. Finally, optimization results comparing the performance of compliant mechanisms with one and two ACJs are also presented. It can be inferred from these results that the number of ACJs and the design of each ACJ determines the stiffness of the bend-and-sweep compliant mechanism. These mechanisms can be used in various applications. The goal of this research is to improve the performance of ornithopters by passively morphing their wings. In order to achieve a bio-inspired wing gait called continuous vortex gait, the wings of the ornithopter need to bend, and sweep simultaneously. This can be achieved by inserting the bend-and-sweep compliant mechanism into the leading edge wing spar of the ornithopters. (paper)

The effect of short-term isometric training on core/torso stiffness.

Science.gov (United States)

Lee, Benjamin; McGill, Stuart

2017-09-01

"Core" exercise is a basic part of many physical training regimens with goals ranging from rehabilitation of spine and knee injuries to improving athletic performance. Core stiffness has been proposed to perform several functions including reducing pain by minimising joint micro-movements, and enhancing strength and speed performance. This study probes the links between a training approach and immediate but temporary changes in stiffness. Passive and active stiffness was measured on 24 participants; 12 having little to no experience in core training (inexperienced), and the other 12 being athletes experienced to core training methods; before and after a 15 min bout of isometric core exercises. Passive stiffness was assessed on a "frictionless" bending apparatus and active stiffness assessed via a quick release mechanism. Short-term isometric core training increased passive and active stiffness in most directions for both inexperienced and experienced participants, passive left lateral bend among experienced participants being the exception (P core stiffness, in this case following a single session. This may influence performance and injury resilience for a brief period.

Tubular bending and pull-out forces in high-curvature well bores

International Nuclear Information System (INIS)

Dareing, D.W.; Ahlers, C.A.

1991-01-01

This paper is concerned with drag forces developed on tubulars in high-curvature well bores typically found in drainhole and horizontal drilling. The dog-leg severity of these types of boreholes are considerably higher than those typically found in conventional directional drilling. The objective of the study was to determine the significance of bending stiffness on drag forces in the pull-out mode. The method of analysis treats the tubular as a multi-spanned curved beam under tension and solves for radial displacements, slope, shear and bending moment over each span. Calculations show that bending stiffness is a minor factor provided there are no locally severe dog legs superimposed in the high-curvature well bore

Where Is the Ulnar Styloid Process? Identification of the Absolute Location of the Ulnar Styloid Process Based on CT and Verification of Neutral Forearm Rotation on Lateral Radiographs of the Wrist.

Science.gov (United States)

Shin, Seung-Han; Lee, Yong-Suk; Kang, Jin-Woo; Noh, Dong-Young; Jung, Joon-Yong; Chung, Yang-Guk

2018-03-01

The location of the ulnar styloid process can be confusing because the radius and the hand rotate around the ulna. The purpose of this study was to identify the absolute location of the ulnar styloid process, which is independent of forearm pronation or supination, to use it as a reference for neutral forearm rotation on lateral radiographs of the wrist. Computed tomography (CT) images of 23 forearms taken with elbow flexion of 70° to 90° were analyzed. The axial CT images were reconstructed to be perpendicular to the distal ulnar shaft. The absolute location of the ulnar styloid process in this study was defined as the position of the ulnar styloid process on the axial plane of the ulnar head relative to the long axis of the humeral shaft with the elbow set in the position for standard lateral radiographs of the wrist. To identify in which direction the ulnar styloid is located on the axial plane of the ulnar head, the angle between "the line of humeral long axis projected on the axial plane of the ulna" and "the line passing the center of the ulnar head and the center of the ulnar styloid" was measured (ulnar styloid direction angle). To identify how volarly or dorsally the ulnar styloid should appear on the true lateral view of the wrist, the ratio of "the volar-dorsal diameter of the ulnar head" and "the distance between the volar-most aspect of the ulnar head and the center of the ulnar styloid" was calculated (ulnar styloid location ratio). The mean ulnar styloid direction angle was 12° dorsally. The mean ulnar styloid location ratio was 1:0.55. The ulnar styloid is located at nearly the ulnar-most (the opposite side of the humerus with the elbow flexed) and slightly dorsal aspects of the ulnar head on the axial plane. It should appear almost midway (55% dorsally) from the ulnar head on the standard lateral view of the wrist in neutral forearm rotation. These location references could help clinicians determine whether the forearm is in neutral or rotated

The design of and chronic tissue response to a composite nerve electrode with patterned stiffness

Science.gov (United States)

Freeberg, M. J.; Stone, M. A.; Triolo, R. J.; Tyler, D. J.

2017-06-01

between implant and explant (p  >  0.15 for all measures). Axonal density and myelin sheath thickness was not significantly different within the electrode compared to sections greater than 2 cm proximal to implanted cuffs (p  >  0.14 for all measures). Significance. We present the design and verification of a novel nerve cuff electrode, the C-FINE. Laminar manufacturing processes allow C-FINE stiffness to be configured for specific applications. Here, the central region in the configuration tested is stiff to reshape or conform to the target nerve, while edges are highly flexible to bend along its length. The C-FINE occupies less volume than other NCEs, making it suitable for implantation in highly mobile locations near joints. Design constraints during simulated transient swelling were verified in vitro. Maintenance of nerve health in various challenging anatomical locations (sciatic and median/ulnar nerves) was verified in a chronic feline model in vivo.

Modeling the dynamic stiffness of cracked reinforced concrete beams under low-amplitude vibration loads

Science.gov (United States)

Xu, Tengfei; Castel, Arnaud

2016-04-01

In this paper, a model, initially developed to calculate the stiffness of cracked reinforced concrete beams under static loading, is used to assess the dynamic stiffness. The model allows calculating the average inertia of cracked beams by taking into account the effect of bending cracks (primary cracks) and steel-concrete bond damage (i.e. interfacial microcracks). Free and forced vibration experiments are used to assess the performance of the model. The respective influence of bending cracks and steel-concrete bond damage on both static and dynamic responses is analyzed. The comparison between experimental and simulated deflections confirms that the effects of both bending cracks and steel-concrete bond loss should be taken into account to assess reinforced concrete stiffness under service static loading. On the contrary, comparison of experimental and calculated dynamic responses reveals that localized steel-concrete bond damages do not influence significantly the dynamic stiffness and the fundamental frequency.

Design of a Variable Stiffness Soft Dexterous Gripper

Science.gov (United States)

Nefti-Meziani, Samia; Davis, Steve

2017-01-01

Abstract This article presents the design of a variable stiffness, soft, three-fingered dexterous gripper. The gripper uses two designs of McKibben muscles. Extensor muscles that increase in length when pressurized are used to form the fingers of the gripper. Contractor muscles that decrease in length when pressurized are then used to apply forces to the fingers through tendons, which cause flexion and extension of the fingers. The two types of muscles are arranged to act antagonistically and this means that by raising the pressure in all of the pneumatic muscles, the stiffness of the system can be increased without a resulting change in finger position. The article presents the design of the gripper, some basic kinematics to describe its function, and then experimental results demonstrating the ability to adjust the bending stiffness of the gripper's fingers. It has been demonstrated that the fingers' bending stiffness can be increased by more than 150%. The article concludes by demonstrating that the fingers can be closed loop position controlled and are able to track step and sinusoidal inputs. PMID:29062630

Ulnar-sided wrist pain. Part I: anatomy and physical examination

International Nuclear Information System (INIS)

Vezeridis, Peter S.; Blazar, Philip; Yoshioka, Hiroshi; Han, Roger

2010-01-01

Ulnar-sided wrist pain is a common complaint, and it presents a diagnostic challenge for hand surgeons and radiologists. The complex anatomy of this region, combined with the small size of structures and subtle imaging findings, compound this problem. A thorough understanding of ulnar-sided wrist anatomy and a systematic clinical examination of this region are essential in arriving at an accurate diagnosis. In part I of this review, ulnar-sided wrist anatomy and clinical examination are discussed for a more comprehensive understanding of ulnar-sided wrist pain. (orig.)

In vivo fluoroscopic kinematography of dynamic radio-ulnar ...

African Journals Online (AJOL)

... canine elbow joint, as part of the physiological kinematic pattern. However, dysplastic elbow joints do not show an increased radio-ulnar translation, and therfore dRUI cannot be considered causative for medial coronoid disease. Keywords: Canine, Elbow dysplasia, Fluoroscopy, Gait analysis, Radio-ulnar incongruence.

Assessment of ulnar variance: a radiological investigation in a Dutch population

Energy Technology Data Exchange (ETDEWEB)

Schuurman, A.H. [Dept. of Plastic, Reconstructive and Hand Surgery, University Medical Centre, Utrecht (Netherlands); Dept. of Plastic Surgery, University Medical Centre, Utrecht (Netherlands); Maas, M.; Dijkstra, P.F. [Dept. of Radiology, Univ. of Amsterdam (Netherlands); Kauer, J.M.G. [Dept. of Anatomy and Embryology, Univ. of Nijmegen (Netherlands)

2001-11-01

Objective: A radiological study was performed to evaluate ulnar variance in 68 Dutch patients using an electronic digitizer compared with Palmer's concentric circle method. Using the digitizer method only, the effect of different wrist positions and grip on ulnar variance was then investigated. Finally the distribution of ulnar variance in the selected patients was investigated also using the digitizer method. Design and patients: All radiographs were performed with the wrist in a standard zero-rotation position (posteroanterior) and in supination (anteroposterior). Palmer's concentric circle method and an electronic digitizer connected to a personal computer were used to measure ulnar variance. The digitizer consists of a Plexiglas plate with an electronically activated grid beneath it. A radiograph is placed on the plate and a cursor activates a point on the grid. Three plots are marked on the radius and one plot on the most distal part of the ulnar head. The digitizer then determines the difference between a radius passing through the radius plots and the ulnar plot. Results and conclusions: Using the concentric circle method we found an ulna plus predominance, but an ulna minus predominance when using the digitizer method. Overall the ulnar variance distribution for Palmer's method was 41.9% ulna plus, 25.7% neutral and 32.4% ulna minus variance, and for the digitizer method was 40.4% ulna plus, 1.5% neutral and 58.1% ulna minus. The percentage ulnar variance greater than 1 mm on standard radiographs increased from 23% to 58% using the digitizer, with maximum grip, clearly demonstrating the (dynamic) effect of grip on ulnar variance. This almost threefold increase was found to be a significant difference. Significant differences were found between ulnar variance when different wrist positions were compared. (orig.)

A comparison of plastic collapse and limit loads for single mitred pipe bends under in-plane bending

International Nuclear Information System (INIS)

Neilson, R.; Wood, J.; Hamilton, R.; Li, H.

2010-01-01

This paper presents a comparison of the plastic collapse loads from experimental in-plane bending tests on three 90 o single un-reinforced mitred pipe bends, with the results from various 3D solid finite element models. The bending load applied reduced the bend angle and in turn, the resulting cross-sectional ovalisation led to a recognised weakening mechanism. In addition, at maximum load there was a reversal in stiffness, characteristic of buckling. This reversal in stiffness was accompanied by significant ovalisation and plasticity at the mitre intersection. Both the weakening mechanism and the post-buckling behaviour are only observable by testing or by including large displacement effects in the plastic finite element solution. A small displacement limit solution with an elastic-perfectly plastic material model overestimated the collapse load by more than 40% and could not reproduce the buckling behaviour. The plastic collapse finite element solution, with large displacements, produced excellent agreement with the experiment. Sufficient experimental detail is presented for these results to be used as a benchmark for analysts in this area. Given the robustness of non-linear solutions in commercial finite element codes and the ready availability of computing resources, it is argued that pressure vessel code developers should now be recommending large displacement analysis as the default position for limit and plastic collapse analyses, rather than expecting engineers to anticipate weakening mechanisms and related non-linear phenomena.

Analysis of ulnar variance as a risk factor for developing scaphoid nonunion.

Science.gov (United States)

Lirola-Palmero, S; Salvà-Coll, G; Terrades-Cladera, F J

2015-01-01

Ulnar variance may be a risk factor of developing scaphoid non-union. A review was made of the posteroanterior wrist radiographs of 95 patients who were diagnosed of scaphoid fracture. All fractures with displacement less than 1mm treated conservatively were included. The ulnar variance was measured in all patients. Ulnar variance was measured in standard posteroanterior wrist radiographs of 95 patients. Eighteen patients (19%) developed scaphoid nonunion, with a mean value of ulnar variance of -1.34 (-/+ 0.85) mm (CI -2.25 - 0.41). Seventy seven patients (81%) healed correctly, and the mean value of ulnar variance was -0.04 (-/+ 1.85) mm (CI -0.46 - 0.38). A significant difference was observed in the distribution of ulnar variance (pvariance less than -1mm, and ulnar variance greater than -1mm. It appears that patients with ulnar variance less than -1mm had an OR 4.58 (CI 1.51 to 13.89) with pvariance less than -1mm have a greater risk of developing scaphoid nonunion, OR 4.58 (CI 1.51 to 13.89) with p<.007. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

Cold intolerance following median and ulnar nerve injuries : prognosis and predictors

NARCIS (Netherlands)

Ruijs, A.C.J; Jaquet, J-B.; van Riel, W. G.; Daanen, H. A M; Hovius, S.E.R.

This study describes the predictors for cold intolerance and the relationship to sensory recovery after median and ulnar nerve injuries. The study population consisted of 107 patients 2 to 10 years after median, ulnar or combined median and ulnar nerve injuries. Patients were asked to fill out the

Cold intolerance following median and ulnar nerve injuries : prognosis and predictors

NARCIS (Netherlands)

Ruijs, A.C.J.; Jaquet, J.B.; Riel, W.G. van; Daanen, H.A.M.; Hovius, S.E.R.

2007-01-01

This study describes the predictors for cold intolerance and the relationship to sensory recovery after median and ulnar nerve injuries. The study population consisted of 107 patients 2 to 10 years after median, ulnar or combined median and ulnar nerve injuries. Patients were asked to fill out the

Relative stiffness of flat conductor cables

Science.gov (United States)

Hankins, J. D.

1976-01-01

The measurement of the bending moment required to obtain a given deflection in short lengths of flat conductor cable (FCC) is presented in this report. Experimental data were taken on 10 different samples of FCC and normalized to express all bending moments (relative stiffness factor) in terms of a cable 5.1 cm (2.0 in.) in width. Data are presented in tabular and graphical form for the covenience of designers who may be interested in finding torques exerted on critical components by short lengths of FCC.

Computer use and ulnar neuropathy: results from a case-referent study

DEFF Research Database (Denmark)

Andersen, JH; Frost, P.; Fuglsang-Frederiksen, A.

2012-01-01

We aimed to evaluate associations between vocational computer use and 1) ulnar neuropathy, and 2) ulnar neuropathy- like symptoms as distinguished by electroneurography. We identified all patients aged 18-65 years, examined at the Department of Neurophysiology on suspicion of ulnar neuropathy, 2001...... was performed by conditional logistic regression.There were a negative association between daily hours of computer use and the two outcomes of interest. Participants who reported their elbow to be in contact with their working table for 2 hours or more during the workday had an elevated risk for ulnar...

Parametric control of structural vibrations and sound radiation by fast time-space variation of distributed stiffness parameters

International Nuclear Information System (INIS)

Krylov, V.I.; Sorokin, S.V.

1998-01-01

The dynamics of a Euler-Bernoulli beam with a time-and-space dependent bending stiffness is studied. The , problem is considered in connection with the application of noise control using smart structures. It is shown that a control for the vibrations of the beam can be achieved by varying the bending stiffness. The technique of direct separation of fast and slow motion coupled with a Green's function method is used to analyze the dynamics of the beam with high-frequency modulation of the stiffness

Different findings in bone scintigraphy between ulnar impaction syndrome and Kienbock's disease

International Nuclear Information System (INIS)

Chung, J.K.; Lee, H.Y.; Lee, M.C.; Baik, G.H.

2002-01-01

Objectives: There is an ethnic variance on the length of the ulnar and radius. In Caucasian the length of the radius is relatively longer than the ulnar, but in Oriental the length of the ulnar is longer. This difference results in the different ethnic prevalence of ulnar impaction syndrome and Kienbock's disease, avascular necrosis of the lunate. It is important to differentiate ulnar impaction syndrome from Kienbock's disease, because they show similar symptoms but need different treatment and different method of operation. Methods: Seventeen patients with the wrist pain were enrolled in this study (mean age: 45+/-13yrs M:F=12:5). Nine patients were diagnosed as Kienbock's disease and Eight patients were diagnosed as ulnar impaction. Three to four hours after injection of 20mCi of Tc-99m MDP, bone scintigraphy images of the both hands were obtained and analyzed visually. Results: In Kienbock's disease, 8 patients showed increased uptake in the lunate with or without other carpal bones. One patient showed photon defect in the lunate. Otherwise in all patients with ulnar impaction syndrome, increased uptakes were found in the lunate, with or without increase uptake in the triquetrum or the distal ulnar, which are related to triangular fibrocartilage complex. Pin hole scintigraphy and pin hole SPECT demonstrated more precise structure of the wrist. Conclusion: We could differentiate ulnar impaction syndrome from Kienbock's disease in bone scan. We should carefully evaluate bone scintigraphic findings in patients with wrist pain

Dynamic ulnar impaction syndrome in tennis players: report of two cases

Directory of Open Access Journals (Sweden)

Edgard de Novaes França Bisneto

Full Text Available ABSTRACT In this report, two tennis players with symptoms of ulnar impaction syndrome are reviewed. Both players have neutral ulnar variance. These cases represent dynamic ulnar impaction syndrome, when the impact between ulna and carpus occurs during conditions of pronated grip. The literature and the treatment of these two cases are discussed.

Mechanical properties of two-way grid shells optimized considering roundness and elastic stiffness

International Nuclear Information System (INIS)

Ogawa, Toshiyuki; Yuta, Nishikawa; Rie, Tateishi; Ohsaki, Makoto

2002-01-01

A single-layer two-way grid shell defined by Bezier surface is optimized by coordinates of the control points as design variables. The purpose of this paper is to find optimal shapes considering roundness and elastic stiffness, and to investigate their mechanical properties. The distance of the center of curvature from the specified point is used for formulating the objective function for generating a round shape. Consider next a problem of minimizing the compliance as mechanical performance measure. The compliance is defined by the external work against the static loads applied to the nodes. The mechanically optimal shape is different from the round shape. Therefore, the multi objective optimization problem is formulated for optimizing the two objectives, which are roundness and the elastic stiffness defined by using the compliance. The constraint method is used for obtaining Pareto optimal solutions between the two objectives. We optimize single-layer two-way grid shells with square and rectangle plans. Mechanical properties of the optimal shapes are investigated by compliance and the distributions of axial force and bending moment. The round shape is significantly dominated by the bending moment and its compliance is large. The bending moment of the mechanically optimal shape is not very large, and the latticed shell has large stiffness through axial deformation. A trade-off shape is round enough, and the influence of the bending moment is smaller than that of the optimal round shape and the elastic stiffness is moderately large

Timoshenko-Wagner-Kappus Torsion Bending Theory and Wind ...

Indian Academy of Sciences (India)

Theory and Wind Tunnel Balance Design. S P Govinda ... The study of torsion and bending has always been a favourite ... Since it was difficult to work quietlyin Petersburg, .... should be stiff and strong to endure shocks and ensure long life.

Median and ulnar neuropathies in university guitarists.

Science.gov (United States)

Kennedy, Rachel H; Hutcherson, Kimberly J; Kain, Jennifer B; Phillips, Alicia L; Halle, John S; Greathouse, David G

2006-02-01

Descriptive study. To determine the presence of median and ulnar neuropathies in both upper extremities of university guitarists. Peripheral nerve entrapment syndromes of the upper extremities are well documented in musicians. Guitarists and plucked-string musicians are at risk for entrapment neuropathies in the upper extremities and are prone to mild neurologic deficits. Twenty-four volunteer male and female guitarists (age range, 18-26 years) were recruited from the Belmont University School of Music and the Vanderbilt University Blair School of Music. Individuals were excluded if they were pregnant or had a history of recent upper extremity or neck injury. Subjects completed a history form, were interviewed, and underwent a physical examination. Nerve conduction status of the median and ulnar nerves of both upper extremities was obtained by performing motor, sensory, and F-wave (central) nerve conduction studies. Descriptive statistics of the nerve conduction study variables were computed using Microsoft Excel. Six subjects had positive findings on provocative testing of the median and ulnar nerves. Otherwise, these guitarists had normal upper extremity neural and musculoskeletal function based on the history and physical examinations. When comparing the subjects' nerve conduction study values with a chart of normal nerve conduction studies values, 2 subjects had prolonged distal motor latencies (DMLs) of the left median nerve of 4.3 and 4.7 milliseconds (normal, DMLs are compatible with median neuropathy at or distal to the wrist. Otherwise, all electrophysiological variables were within normal limits for motor, sensory, and F-wave (central) values. However, comparison studies of median and ulnar motor latencies in the same hand demonstrated prolonged differences of greater than 1.0 milliseconds that affected the median nerve in 2 additional subjects, and identified contralateral limb involvement in a subject with a prolonged distal latency. The other 20

The superficial ulnar artery: development and clinical significance Artéria ulnar superficial: desenvolvimento e relevância clínica

Directory of Open Access Journals (Sweden)

Srinivasulu Reddy

2007-09-01

Full Text Available The principal arteries of the upper limb show a wide range of variation that is of considerable interest to orthopedic surgeons, plastic surgeons, radiologists and anatomists. We present here a case of superficial ulnar artery found during the routine dissection of right upper limb of a 50-year-old male cadaver. The superficial ulnar artery originated from the brachial artery, crossed the median nerve anteriorly and ran lateral to this nerve and the brachial artery. The superficial ulnar artery in the arm gave rise to a narrow muscular branch to the biceps brachii. At the elbow level the artery ran superficial to the bicipital aponeurosis where it was crossed by the median cubital vein. It then ran downward and medially superficial to the forearm flexor muscles, and then downward to enter the hand. At the palm, it formed the superficial and deep palmar arches together with the branches of the radial artery. The presence of a superficial ulnar artery is clinically important when raising forearm flaps in reconstructive surgery. The embryology and clinical significance of the variation are discussed.As principais artérias do membro superior apresentam uma ampla variação, que é relativamente importante a cirurgiões ortopédicos e plásticos, radiologistas e anatomistas.Apresentamosumcaso de artéria ulnar superficial encontrada durante dissecção de rotina de membro superior direito de um cadáver masculino de 50 anos de idade.Aartéria ulnar superficial originava-se da artéria braquial, cruzava o nervo mediano anteriormente e percorria lateralmente esse nervo e a artéria braquial. A artéria ulnar superficial no braço deu origem a um ramo muscular estreito do músculo bíceps braquial. Ao nível do cotovelo, a artéria percorria superficialmente a aponeurose bicipital, onde era cruzada pela veia cubital mediana. Percorria, então, em sentido descendente e medialmente superficial aos músculos flexores do antebraço, e então descendia para

Drilling the near cortex with elongated figure-of-8 holes to reduce the stiffness of a locking compression plate construct.

Science.gov (United States)

Chen, Jerry Yongqiang; Zhou, Zhihong; Ang, Benjamin Fu Hong; Yew, Andy Khye Soon; Chou, Siaw Meng; Chia, Shi-Lu; Koh, Joyce Suang Bee; Howe, Tet Sen

2015-12-01

To compare the stiffness of locking compression plate (LCP) constructs with or without drilling the near cortex with elongated figure-of-8 holes. 24 synthetic bones were sawn to create a 10-mm gap and were fixed with a 9-hole 4.5-mm narrow LCP. In 12 bones, the near cortex of the adjacent holes to the LCP holes was drilled to create elongated figure-of-8 holes before screw insertion. The stiffness of LCP constructs under axial loading or 4-point bending was assessed by (1) dynamic quasi-physiological testing for fatigue strength, (2) quasi-static testing for stiffness, and (3) testing for absolute strength to failure. None of the 24 constructs had subcatastrophic or catastrophic failure after 10 000 cycles of fatigue loading (p=1.000). The axial stiffness reduced by 16% from 613±62 to 517±44 N/mm (p=0.012) in the case group, whereas the bending stiffness was 16±1 Nm2 in both groups (p=1.000). The maximum axial load to catastrophic failure was 1596±84 N for the control group and 1627±48 N for the case group (p=0.486), whereas the maximum bending moment to catastrophic failure was 79±12 and 80±10 Nm, respectively (p=0.919). Drilling the near cortex with elongated figure-of-8 holes reduces the axial stiffness of the LCP construct, without compromising its bending stiffness or strength.

Ulnar nerve entrapment by anconeus epitrochlearis ligament.

LENUS (Irish Health Repository)

Tiong, William H C

2012-01-01

Ulnar nerve entrapment at the elbow is the second most common upper limb entrapment neuropathy other than carpal tunnel syndrome. There have been many causes identified ranging from chronic aging joint changes to inflammatory conditions or systemic disorders. Among them, uncommon anatomical variants accounts for a small number of cases. Here, we report our experience in managing ulnar nerve entrapment caused by a rare vestigial structure, anconeus epitrochlearis ligament, and provide a brief review of the literature of its management.

Stiffness and frictional resistance of a superelastic nickel-titanium orthodontic wire with low-stress hysteresis.

Science.gov (United States)

Liaw, Yu-Cheng; Su, Yu-Yu M; Lai, Yu-Lin; Lee, Shyh-Yuan

2007-05-01

Stress-induced martensite formation with stress hysteresis that changes the elasticity and stiffness of nickel-titanium (Ni-Ti) wire influences the sliding mechanics of archwire-guided tooth movement. This in-vitro study investigated the frictional behavior of an improved superelastic Ni-Ti wire with low-stress hysteresis. Improved superelastic Ni-Ti alloy wires (L & H Titan, Tomy International, Tokyo, Japan) with low-stress hysteresis were examined by using 3-point bending and frictional resistance tests with a universal test machine at a constant temperature of 35 degrees C, and compared with the former conventional austenitic-active superelastic Ni-Ti wires (Sentalloy, Tomy International). Wire stiffness levels were derived from differentiation of the polynomial regression of the unloading curves, and values for kinetic friction were measured at constant bending deflection distances of 0, 2, 3, and 4 mm, respectively. Compared with conventional Sentalloy wires, the L & H Titan wire had a narrower stress hysteresis including a lower loading plateau and a higher unloading plateau. In addition, L & H Titan wires were less stiff than the Sentalloy wires during most unloading stages. Values of friction measured at deflections of 0, 2, and 3 mm were significantly (P Sentalloy wires at all bending deflections (P <.05). Stress-induced martensite formation significantly reduced the stiffness and thus could be beneficial to decrease the binding friction of superelastic Ni-Ti wires during sliding with large bending deflections. Austenitic-active alloy wires with low-stress hysteresis and lower stiffness and friction offer significant potential for further investigation.

A thermo-viscoelastic approach for the characterization and modeling of the bending behavior of thermoplastic composites – Part II

NARCIS (Netherlands)

Ropers, Steffen; Sachs, Ulrich; Kardos, Marton; Osswald, Tim A.

2017-01-01

A proper description of the bending behavior is crucial to obtain accurate forming simulations, especially for continuous fiber-reinforced thermoplastic composites. These materials exhibit a highly temperature and bending-curvature dependent bending stiffness. These dependencies make the property

Association between distal ulnar morphology and extensor carpi ulnaris tendon pathology

International Nuclear Information System (INIS)

Chang, Connie Y.; Huang, Ambrose J.; Bredella, Miriam A.; Kattapuram, Susan V.; Torriani, Martin

2014-01-01

The purpose of this study was to evaluate the association between distal ulnar morphology and extensor carpi ulnaris (ECU) tendon pathology. We retrospectively reviewed 71 adult wrist MRI studies with ECU tendon pathology (tenosynovitis, tendinopathy, or tear), and/or ECU subluxation. Subjects did not have a history of trauma, surgery, infection, or inflammatory arthritis. MRI studies from 46 subjects without ECU tendon pathology or subluxation were used as controls. The following morphological parameters of the distal ulna were measured independently by two readers: ulnar variance relative to radius, ulnar styloid process length, ECU groove depth and length. Subjects and controls were compared using Student's t test. Inter-observer agreement (ICC) was calculated. There was a significant correlation between negative ulnar variance and ECU tendon pathology (reader 1 [R1], P = 0.01; reader 2 [R2], P 0.64 for all parameters. Distal ulnar morphology may be associated with ECU tendon abnormalities. (orig.)

Impact of ancestry and body size on sonographic ulnar nerve dimensions

International Nuclear Information System (INIS)

Childs, Jessie T.; Phillips, Maureen; Thoirs, Kerry A.

2012-01-01

Introduction: The purpose of this study was to investigate the impact that geographic ancestry and body size have on ultrasonographic measurements of the ulnar nerve size measured at the elbow. Materials and methods: We performed anthropometric measurements of body size and ultrasonographic measurements of the ulnar nerve at the elbow on 13 Vietnamese and 24 European participants. Regression analysis was used to determine the effect of body size and geographic ancestry on ulnar nerve size. Results: BMI had the greatest impact on ulnar nerve size. The short axis diameter was least resilient, and the long axis diameter was the most resilient to the effects of body size and geographic ancestry. Discussion: The long axis diameter has an apparent immunity to the influences of overall body size, arm size, or geographic ancestry and has the most potential as a sensitive discriminator between normal nerves and nerves affected by ulnar neuropathy at the elbow.

Clinical and X-ray investigations on congenital radio-ulnar synostosis

International Nuclear Information System (INIS)

Heisel, A.

1982-01-01

Out of 13 patients with cogenital radio-ulnar synostosis, 10 could be subjected to clinical and X-ray examination and chromosome analysis. In all the family histories the radio-ulnar synostosis was an isolated event. In no case was definite heredity of the same malformation confirmed. In most cases the radio-ulnar synostosis was an isolated malformation. 7 patients were of female, 6 of male sex. In 5 cases the synostosis was bi-lateral, in 8 cases it was unilateral without preference of either side of the body. In 2 out of 10 patients subjected to chromosome analysis gonosomal aneuploidy was found. More often than hitherto supposed, radio-ulnar synostosis seems to be associated with lower forms of polysomia of the x-chromosomes. 15 out of 18 synostoses belonged to type II, 3 to type I. The different types represent merely differring degrees of manifestation of the same deformity occurring bilaterally in one person. All patients with radio-ulnar synostosis exhibited a high degree of functional tolerance to the malformation. The development in child age and the educational and professional record were hardly impaired. (orig./MG) [de

Ulnar nerve entrapment in Guyon's canal due to a lipoma.

Science.gov (United States)

Ozdemir, O; Calisaneller, T; Gerilmez, A; Gulsen, S; Altinors, N

2010-09-01

Guyon's canal syndrome is an ulnar nerve entrapment at the wrist or palm that can cause motor, sensory or combined motor and sensory loss due to various factors . In this report, we presented a 66-year-old man admitted to our clinic with a history of intermittent pain in the left palm and numbness in 4th and 5th finger for two years. His neurological examination revealed a sensory impairment in the right fifth finger. Also, physical examination displayed a subcutaneous mobile soft tissue in ulnar side of the wrist. Electromyographic examination confirmed the diagnosis of type-1 Guyon's canal syndrome. Under axillary blockage, a lipoma compressing the ulnar nerve was excised totally and ulnar nerve was decompressed. The symptoms were improved after the surgery and patient was symptom free on 3rd postoperative week.

Variable stiffness corrugated composite structure with shape memory polymer for morphing skin applications

Science.gov (United States)

Gong, Xiaobo; Liu, Liwu; Scarpa, Fabrizio; Leng, Jinsong; Liu, Yanju

2017-03-01

This work presents a variable stiffness corrugated structure based on a shape memory polymer (SMP) composite with corrugated laminates as reinforcement that shows smooth aerodynamic surface, extreme mechanical anisotropy and variable stiffness for potential morphing skin applications. The smart composite corrugated structure shows a low in-plane stiffness to minimize the actuation energy, but also possess high out-of-plane stiffness to transfer the aerodynamic pressure load. The skin provides an external smooth aerodynamic surface because of the one-sided filling with the SMP. Due to variable stiffness of the shape memory polymer the morphing skin exhibits a variable stiffness with a change of temperature, which can help the skin adjust its stiffness according different service environments and also lock the temporary shape without external force. Analytical models related to the transverse and bending stiffness are derived and validated using finite element techniques. The stiffness of the morphing skin is further investigated by performing a parametric analysis against the geometry of the corrugation and various sets of SMP fillers. The theoretical and numerical models show a good agreement and demonstrate the potential of this morphing skin concept for morphing aircraft applications. We also perform a feasibility study of the use of this morphing skin in a variable camber morphing wing baseline. The results show that the morphing skin concept exhibits sufficient bending stiffness to withstand the aerodynamic load at low speed (less than 0.3 Ma), while demonstrating a large transverse stiffness variation (up to 191 times) that helps to create a maximum mechanical efficiency of the structure under varying external conditions.

Ulnar-sided wrist pain. II. Clinical imaging and treatment

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Atsuya; Souza, Felipe [Brigham and Women' s Hospital, Department of Radiology, Boston, MA (United States); Vezeridis, Peter S.; Blazar, Philip [Brigham and Women' s Hospital, Department of Orthopaedic Surgery, Boston, MA (United States); Yoshioka, Hiroshi [Brigham and Women' s Hospital, Department of Radiology, Boston, MA (United States); University of California-Irvine, Department of Radiological Sciences, Irvine, CA (United States); UC Irvine Medical Center, Department of Radiological Sciences, Orange, CA (United States)

2010-09-15

Pain at the ulnar aspect of the wrist is a diagnostic challenge for hand surgeons and radiologists due to the small and complex anatomical structures involved. In this article, imaging modalities including radiography, arthrography, ultrasound (US), computed tomography (CT), CT arthrography, magnetic resonance (MR) imaging, and MR arthrography are compared with regard to differential diagnosis. Clinical imaging findings are reviewed for a more comprehensive understanding of this disorder. Treatments for the common diseases that cause the ulnar-sided wrist pain including extensor carpi ulnaris (ECU) tendonitis, flexor carpi ulnaris (FCU) tendonitis, pisotriquetral arthritis, triangular fibrocartilage complex (TFCC) lesions, ulnar impaction, lunotriquetral (LT) instability, and distal radioulnar joint (DRUJ) instability are reviewed. (orig.)

Functions of fish skin: flexural stiffness and steady swimming of longnose gar, Lepisosteus osseus

Science.gov (United States)

Long; Hale; Mchenry; Westneat

1996-01-01

The functions of fish skin during swimming remain enigmatic. Does skin stiffen the body and alter the propagation of the axial undulatory wave? To address this question, we measured the skin's in situ flexural stiffness and in vivo mechanical role in the longnose gar Lepisosteus osseus. To measure flexural stiffness, dead gar were gripped and bent in a device that measured applied bending moment (N m) and the resulting midline curvature (m-1). From these values, the flexural stiffness of the body (EI in N m2) was calculated before and after sequential alterations of skin structure. Cutting of the dermis between two caudal scale rows significantly reduced the flexural stiffness of the body and increased the neutral zone of curvature, a region of bending without detectable stiffness. Neither bending property was significantly altered by the removal of a caudal scale row. These alterations in skin structure were also made in live gar and the kinematics of steady swimming was measured before and after each treatment. Cutting of the dermis between two caudal scale rows, performed under anesthesia, changed the swimming kinematics of the fish: tailbeat frequency (Hz) and propulsive wave speed (body lengths per second, L s-1) decreased, while the depth (in L) of the trailing edge of the tail increased. The decreases in tailbeat frequency and wave speed are consistent with predictions of the theory of forced, harmonic vibrations; wave speed, if equated with resonance frequency, is proportional to the square root of a structure's stiffness. While it did not significantly reduce the body's flexural stiffness, surgical removal of a caudal scale row resulted in increased tailbeat amplitude and the relative total hydrodynamic power. In an attempt to understand the specific function of the scale row, we propose a model in which a scale row resists medio-lateral force applied by a single myomere, thus functioning to enhance mechanical advantage for bending. Finally, surgical

An experimental investigation on bending stiffness and neutral axis depth variation of over-reinforced high strength concrete beams

International Nuclear Information System (INIS)

Mohammadhassani, Mohammad; Bin Jumaat, Mohd Zamin; Chemrouk, Mohamed; Akbar Maghsoudi, Ali; Jameel, Mohammed; Akib, Shatirah

2011-01-01

Highlights: → Improvement of the assessment of correspond stress for calculation of modules of elasticity → better evaluation of cracked moment of inertia. → Low distinction of neutral axis depth → low bending stiffness variation. → Rate of slope in the line connecting the origin of first crack to yield point of N.A.D-LOAD graph → rate of ductility of beam section. - Abstract: The present work is an attempt to study the neutral axis variation and the evolution of the moment inertia with the loading of over reinforced high strength concrete sections in conjunction with ACI 318-05. In this sense, four high strength concrete beams, having different tension reinforcement quantities expressed as proportions of the balanced steel ratio (0.75ρ b , 0.85ρ b , ρ b , 1.2ρ b ) were tested. Measurements of the deflection and the reinforcement and concrete strains of all specimens were made during the loading process. The load-neutral axis depth variation and the load-section stiffness curves were drawn. The slope of the line connecting the origin of the first crack to the initial yielding of the failure point in the neutral axis depth-load graphs shows the rate of ductility; ductile behaviour in the beam increases as the slope becomes steeper. Based on the results of this study, it is recommended that the modulus of elasticity of concrete E c be reviewed and evaluated at a stress higher than 0.5f ' c for the determination of the cracked moment of inertia.

Quantification of hand function by power grip and pinch strength force measurements in ulnar nerve lesion simulated by ulnar nerve block.

Science.gov (United States)

Wachter, Nikolaus Johannes; Mentzel, Martin; Krischak, Gert D; Gülke, Joachim

2017-06-24

In the assessment of hand and upper limb function, grip strength is of the major importance. The measurement by dynamometers has been established. In this study, the effect of a simulated ulnar nerve lesion on different grip force measurements was evaluated. In 25 healthy volunteers, grip force measurement was done by the JAMAR dynamometer (Fabrication Enterprises Inc, Irvington, NY) for power grip and by a pinch strength dynamometer for tip pinch strength, tripod grip, and key pinch strength. A within-subject research design was used in this prospective study. Each subject served as the control by preinjection measurements of grip and pinch strength. Subsequent measurements after ulnar nerve block were used to examine within-subject change. In power grip, there was a significant reduction of maximum grip force of 26.9% with ulnar nerve block compared with grip force without block (P force could be confirmed. However, the assessment of other dimensions of hand strength as tip pinch, tripod pinch and key pinch had more relevance in demonstrating hand strength changes resulting from an distal ulnar nerve lesion. The measurement of tip pinch, tripod grip and key pinch can improve the follow-up in hand rehabilitation. II. Copyright © 2017 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Stiffness Customization and Patterning for Property Modulation of Silicone-Based Soft Pneumatic Actuators.

Science.gov (United States)

Sun, Yi; Yap, Hong Kai; Liang, Xinquan; Guo, Jin; Qi, Peng; Ang, Marcelo H; Yeow, Chen-Hua

2017-09-01

Soft pneumatic actuators (SPAs), as novel types of motion drivers for robotic devices, excel in many applications, such as rehabilitation and biomimicry, which demand compliance and softness. To further expand their scope of utilization, the SPAs should be customizable to meet the distinctive requirements of different applications. This article proposes a novel perspective on the SPA working mechanism based on stiffness distribution and then presents a versatile method called stiffness customization and patterning (SCP) for SPA body stiffness layout as a novel attempt to customize SPAs with distinctive properties. We fabricated a hybrid type of material combining unstretchable material and silicone with customizable aggregated elasticity. The tensile results showed that embedding unstretchable material directly increases the stiffness of the hybrid material sample, and our stress-strain model for SCP is able to adequately predict the elasticity of hybrid samples with specific material ratios. By applying this approach to bending-type SPAs, we are able to mitigate SPA buckling, a main failure mode of SPAs, and improve the SPA tip force by using hybrid material with globally increased stiffness. We also diversify bending modalities with different stiffness configurations in the hybrid material. SCP offers numerous ways to engineer SPAs for more applications.

Out-of-Plane Bending Properties of Out-of-Autoclave Thermosetting Prepregs during Forming Processes

OpenAIRE

Hassan A. Alshahrani; Mehdi H. Hojjati

2016-01-01

In order to predict and model wrinkling which is caused by out of plane deformation due to compressive loading in the plane of the material during composite prepregs forming, it is necessary to quantitatively understand the relative magnitude of the bending stiffness. This study aims to examine the bending properties of out-of-autoclave (OOA) thermosetting prepreg under vertical cantilever test condition. A direct method for characterizing the bending behavior of composite prepregs was develo...

How does ulnar shortening osteotomy influence morphologic changes in the triangular fibrocartilage complex?

Science.gov (United States)

Yamanaka, Yoshiaki; Nakamura, Toshiyasu; Sato, Kazuki; Toyama, Yoshiaki

2014-11-01

Ulnar shortening osteotomy often is indicated for treatment of injuries to the triangular fibrocartilage complex (TFCC). However, the effect of ulnar shortening osteotomy on the changes in shape of the TFCC is unclear. In our study, quantitative evaluations were performed using MRI to clarify the effect of ulnar shortening on triangular fibrocartilage (TFC) thickness attributable to disc regeneration of the TFC and TFC angle attributable to the suspension effect of ulnar shortening on the TFC. The purposes of this study were (1) to compare preoperative and postoperative TFC thickness and TFC angle on MR images to quantitatively evaluate the effect of ulnar shortening osteotomy on disc regeneration and the suspension effect on the TFC; and (2) to assess whether changes in TFC thickness and TFC angle correlated with the Mayo wrist score. Between 1995 and 2008, 256 patients underwent ulnar shortening osteotomy for TFCC injuries. The minimum followup was 24 months (mean, 51 months; range, 24-210 months). A total of 79 patients (31%) with complete followup including preoperative and postoperative MR images and the Mayo wrist score was included in this retrospective study. Evaluation of the postoperative MR images and the Mayo wrist score were performed at the final followup. The remaining 177 patients did not undergo postoperative MRI, or they had a previous fracture, large tears of the disc proper, or were lost to followup. Two orthopaedists, one of whom performed the surgeries, measured the TFC thickness and the TFC angle on coronal MR images before and after surgery for each patient. Correlations of the percent change in the TFC thickness and the magnitude of TFC angle change with age, sex, postoperative MR images, extent of ulnar shortening, preoperative ulnar variance, and postoperative Mayo wrist score were assessed. Stepwise regression analysis showed a correlation between the percent change in TFC thickness and preoperative ulnar variance (R2=0.21; β=-0.33; 95

Comparison of femoropopliteal artery stents under axial and radial compression, axial tension, bending, and torsion deformations.

Science.gov (United States)

Maleckis, Kaspars; Deegan, Paul; Poulson, William; Sievers, Cole; Desyatova, Anastasia; MacTaggart, Jason; Kamenskiy, Alexey

2017-11-01

High failure rates of Peripheral Arterial Disease (PAD) stenting appear to be associated with the inability of certain stent designs to accommodate severe biomechanical environment of the femoropopliteal artery (FPA) that bends, twists, and axially compresses during limb flexion. Twelve Nitinol stents (Absolute Pro, Supera, Lifestent, Innova, Zilver, Smart Control, Smart Flex, EverFlex, Viabahn, Tigris, Misago, and Complete SE) were quasi-statically tested under bench-top axial and radial compression, axial tension, bending, and torsional deformations. Stents were compared in terms of force-strain behavior, stiffness, and geometrical shape under each deformation mode. Tigris was the least stiff stent under axial compression (6.6N/m axial stiffness) and bending (0.1N/m) deformations, while Smart Control was the stiffest (575.3N/m and 105.4N/m, respectively). Under radial compression Complete SE was the stiffest (892.8N/m), while Smart Control had the lowest radial stiffness (211.0N/m). Viabahn and Supera had the lowest and highest torsional stiffness (2.2μNm/° and 959.2μNm/°), respectively. None of the 12 PAD stents demonstrated superior characteristics under all deformation modes and many experienced global buckling and diameter pinching. Though it is yet to be determined which of these deformation modes might have greater clinical impact, results of the current analysis may help guide development of new stents with improved mechanical characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ulnar hammer syndrome: a systematic review of the literature.

Science.gov (United States)

Vartija, Larisa; Cheung, Kevin; Kaur, Manraj; Coroneos, Christopher James; Thoma, Achilleas

2013-11-01

Ulnar hammer syndrome is an uncommon form of arterial insufficiency. Many treatments have been described, and debate continues about the best option. The goal of this systematic review was to determine whether ulnar hammer syndrome has an occupational association, to identify the most reliable diagnostic test, and to determine the best treatment modality. A comprehensive literature search was conducted using the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, and EMBASE. Data from articles meeting inclusion criteria were collected in duplicate. Methodological quality of studies was assessed using the Methodological Index for Nonrandomized Studies scale. Thirty studies were included in the systematic review. No randomized controlled trials were identified. There is low-quality evidence suggestive of an association between exposure to repetitive hand trauma and vibration and ulnar hammer syndrome. Various diagnostic investigations were used, but few were compared, making it difficult to determine the most reliable diagnostic test. Numerous nonoperative and operative treatments were reported. With nonoperative treatment, 12 percent had complete resolution and 70 percent had partial resolution of their symptoms. Of patients treated operatively, 42.5 percent had complete resolution and 42.5 percent had partial resolution of their symptoms. The heterogeneity in study design and outcome measures limits definitive conclusions about occupational association, best diagnostic test, and treatment for ulnar hammer syndrome. However, there is low-quality evidence that suggests that most patients with ulnar hammer syndrome will have partial relief of symptoms with nonoperative treatment, and operative treatment results in complete or partial resolution of symptoms in the majority of cases. Therapeutic, IV.

Magnetically Assisted Bilayer Composites for Soft Bending Actuators

Directory of Open Access Journals (Sweden)

Sung-Hwan Jang

2017-06-01

Full Text Available This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics.

Magnetically Assisted Bilayer Composites for Soft Bending Actuators.

Science.gov (United States)

Jang, Sung-Hwan; Na, Seon-Hong; Park, Yong-Lae

2017-06-12

This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics.

Reconstruction of hand contracture by reverse ulnar perforator flap

Directory of Open Access Journals (Sweden)

Cengiz Eser

2016-04-01

Full Text Available Hand burn scar contractures affect patients in aesthetic and functional aspects. After releasing these scars, the defects should be repaired. The reconstruction methods include primary suturation, Z plasty, skin grafting, local or free flaps, etc. All methods have their own advantages and disadvantages. One of the most useful flaps is the reverse ulnar perforator flap. We performed a two-staged procedure for repairing a post-burn contracture release defect in a 40-year-old male. In the first stage we applied reverse ulnar perforator flap for the hand defect, and ulnar artery and vein repair in the second stage. In conclusion, this two-staged procedure is a non-primary but useful option for hand and finger defects and prevents major vascular structure damage of the forearm. [Hand Microsurg 2016; 5(1.000: 40-43

Prolonged phone-call posture causes changes of ulnar motor nerve conduction across elbow.

Science.gov (United States)

Padua, Luca; Coraci, Daniele; Erra, Carmen; Doneddu, Pietro Emiliano; Granata, Giuseppe; Rossini, Paolo Maria

2016-08-01

Postures and work-hobby activities may play a role in the origin and progression of ulnar neuropathy at the elbow (UNE), whose occurrence appears to be increasing. The time spent on mobile-phone has increased in the last decades leading to an increased time spent with flexed elbow (prolonged-phone-posture, PPP). We aimed to assess the effect of PPP both in patients with symptoms of UNE and in symptom-free subjects. Patients with pure sensory symptoms of UNE and negative neurophysiological tests (MIN-UNE) and symptom-free subjects were enrolled. We evaluated ulnar motor nerve conduction velocity across elbow at baseline and after 6, 9, 12, 15, and 18min of PPP in both groups. Fifty-six symptom-free subjects and fifty-eight patients were enrolled. Globally 186 ulnar nerves from 114 subjects were studied. Conduction velocity of ulnar nerve across the elbow significantly changed over PPP time in patients with MIN-UNE, showing a different evolution between the two groups. PPP causes a modification of ulnar nerve functionality in patients with MIN-UNE. PPP may cause transient stress of ulnar nerve at elbow. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Origami tubes assembled into stiff, yet reconfigurable structures and metamaterials.

Science.gov (United States)

Filipov, Evgueni T; Tachi, Tomohiro; Paulino, Glaucio H

2015-10-06

Thin sheets have long been known to experience an increase in stiffness when they are bent, buckled, or assembled into smaller interlocking structures. We introduce a unique orientation for coupling rigidly foldable origami tubes in a "zipper" fashion that substantially increases the system stiffness and permits only one flexible deformation mode through which the structure can deploy. The flexible deployment of the tubular structures is permitted by localized bending of the origami along prescribed fold lines. All other deformation modes, such as global bending and twisting of the structural system, are substantially stiffer because the tubular assemblages are overconstrained and the thin sheets become engaged in tension and compression. The zipper-coupled tubes yield an unusually large eigenvalue bandgap that represents the unique difference in stiffness between deformation modes. Furthermore, we couple compatible origami tubes into a variety of cellular assemblages that can enhance mechanical characteristics and geometric versatility, leading to a potential design paradigm for structures and metamaterials that can be deployed, stiffened, and tuned. The enhanced mechanical properties, versatility, and adaptivity of these thin sheet systems can provide practical solutions of varying geometric scales in science and engineering.

HIGH ORIGIN OF SUPERFICIAL ULNAR ARTERY- A CASE REPORT

Directory of Open Access Journals (Sweden)

Anjana Jayakumaran Nair

2017-03-01

Full Text Available BACKGROUND High origin and superficially placed ulnar artery is a rare anatomical variant that usually arises either in the axilla or arm and runs a superficial course in the forearm, enters the hand and participates in the formation of superficial palmar arch. During routine dissection of cadavers in our department, we observed a unilateral case of high origin and superficial ulnar artery in a human male cadaver. It originated from the brachial artery in the lower third of arm 4 cm above its bifurcation. From its origin, it passed downwards along the medial aspect of forearm, superficial to the flexors, entered hand superficial to the flexor retinaculum and formed superficial palmar arch. The knowledge of existence of a superficial ulnar artery is important during vascular and reconstructive surgery and also in evaluation of angiographic images. Superficial position makes it more vulnerable to trauma and more accessible to cannulation.

21 CFR 888.3810 - Wrist joint ulnar (hemi-wrist) polymer prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint ulnar (hemi-wrist) polymer prosthesis. 888.3810 Section 888.3810 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-wrist) polymer prosthesis. (a) Identification. A wrist joint ulnar (hemi-wrist) polymer prosthesis...

Damage severity estimation from the global stiffness decrease

International Nuclear Information System (INIS)

Nitescu, C; Gillich, G R; Manescu, T; Korka, Z I; Abdel Wahab, M

2017-01-01

In actual damage detection methods, localization and severity estimation can be treated separately. The severity is commonly estimated using fracture mechanics approach, with the main disadvantage of involving empirically deduced relations. In this paper, a damage severity estimator based on the global stiffness reduction is proposed. This feature is computed from the deflections of the intact and damaged beam, respectively. The damage is always located where the bending moment achieves maxima. If the damage is positioned elsewhere on the beam, its effect becomes lower, because the stress is produced by a diminished bending moment. It is shown that the global stiffness reduction produced by a crack is the same for all beams with a similar cross-section, regardless of the boundary conditions. One mathematical relation indicating the severity and another indicating the effect of removing damage from the beam. Measurements on damaged beams with different boundary conditions and cross-sections are carried out, and the location and severity are found using the proposed relations. These comparisons prove that the proposed approach can be used to accurately compute the severity estimator. (paper)

Association between distal ulnar morphology and extensor carpi ulnaris tendon pathology

Energy Technology Data Exchange (ETDEWEB)

Chang, Connie Y.; Huang, Ambrose J.; Bredella, Miriam A.; Kattapuram, Susan V.; Torriani, Martin [General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts, Boston, MA (United States)

2014-06-15

The purpose of this study was to evaluate the association between distal ulnar morphology and extensor carpi ulnaris (ECU) tendon pathology. We retrospectively reviewed 71 adult wrist MRI studies with ECU tendon pathology (tenosynovitis, tendinopathy, or tear), and/or ECU subluxation. Subjects did not have a history of trauma, surgery, infection, or inflammatory arthritis. MRI studies from 46 subjects without ECU tendon pathology or subluxation were used as controls. The following morphological parameters of the distal ulna were measured independently by two readers: ulnar variance relative to radius, ulnar styloid process length, ECU groove depth and length. Subjects and controls were compared using Student's t test. Inter-observer agreement (ICC) was calculated. There was a significant correlation between negative ulnar variance and ECU tendon pathology (reader 1 [R1], P = 0.01; reader 2 [R2], P < 0.0001; R1 and R2 averaged data, P < 0.0001) and ECU tendon subluxation (P = 0.001; P = 0.0001; P < 0.0001). In subjects with ECU tendon subluxation there was also a trend toward a shorter length (P = 0.3; P <0.0001; P = 0.001) and a shallower ECU groove (P = 0.01; P = 0.03; P = 0.01; R1 and R2 averaged data with Bonferroni correction, P = 0.08). ECU groove depth (P = 0.6; P = 0.8; P = 0.9) and groove length (P = 0.1; P = 0.4; P = 0.7) showed no significant correlation with ECU tendon pathology, and length of the ulnar styloid process showed no significant correlation with ECU tendon pathology (P = 0.2; P = 0.3; P = 0.2) or subluxation (P = 0.4; P = 0.5; P = 0.5). Inter-observer agreement (ICC) was >0.64 for all parameters. Distal ulnar morphology may be associated with ECU tendon abnormalities. (orig.)

Cooling modifies mixed median and ulnar palmar studies in carpal tunnel syndrome.

Science.gov (United States)

Araújo, Rogério Gayer Machado de; Kouyoumdjian, João Aris

2007-09-01

Temperature is an important and common variable that modifies nerve conduction study parameters in practice. Here we compare the effect of cooling on the mixed palmar median to ulnar negative peak-latency difference (PMU) in electrodiagnosis of carpal tunnel syndrome (CTS). Controls were 22 subjects (19 women, mean age 42.1 years, 44 hands). Patients were diagnosed with mild symptomatic CTS (25 women, mean age 46.6 years, 34 hands). PMU was obtained at the usual temperature, >32 degrees C, and after wrist/hand cooling to PMU and mixed ulnar palmar latency in patients versus controls. We concluded that cooling significantly modifies the PMU. We propose that the latencies of compressed nerve overreact to cooling and that this response could be a useful tool for incipient CTS electrodiagnosis. There was a significant latency overreaction of the ulnar nerve to cooling in CTS patients. We hypothesize that subclinical ulnar nerve compression is associated with CTS.

Donor-site morbidity of the radial forearm free flap versus the ulnar forearm free flap.

Science.gov (United States)

Hekner, Dominique D; Abbink, Jan H; van Es, Robert J; Rosenberg, Antoine; Koole, Ronald; Van Cann, Ellen M

2013-08-01

Donor-site morbidity following harvest of the radial forearm free flap was compared with that following harvest of the ulnar forearm free flap. Twenty-eight radial forearm and 27 ulnar forearm flaps were harvested in 55 patients with head and neck defects. Pressure perception was measured with Semmes-Weinstein monofilaments. Cold perception was tested with chloroethyl. Donor-site healing was evaluated. Patients were interviewed about grip and pinch strength and donor-site appearance. In the radial forearm free flap group, pressure perception and cold perception were reduced in the donor hand, whereas in the ulnar group, no differences were observed between the donor and unoperated hands. In the radial forearm group, 15 percent of patients experienced reduced strength in the donor hand, whereas in the ulnar forearm group, none of the patients reported reduced strength in the donor hand. In the radial forearm group, 14 percent had partial or complete loss of the skin graft, whereas in the ulnar forearm group, 4 percent had partial loss of the skin graft. In the radial forearm group, 18 percent of patients were dissatisfied with the appearance of the donor site, and no complaints were reported in the ulnar forearm group. The authors' study shows less donor site-morbidity following harvest of the ulnar forearm free flap than following harvest of the radial forearm free flap. These results emphasize that the ulnar forearm free flap should be considered as an alternative for the radial forearm free flap for reconstruction of soft-tissue defects. Therapeutic, III.

Modal Properties and Stability of Bend-Twist Coupled Wind Turbine Blades

DEFF Research Database (Denmark)

Stäblein, Alexander R.; Hansen, Morten Hartvig; Verelst, David Robert

2017-01-01

a steady-state equilibrium using the aero-servo-elastic tool HAWCStab2 which has been extended by a beam element that allows for fully coupled cross-sectional properties. Bend-twist coupling is introduced in the cross-sectional stiffness matrix by means of coupling coefficients that introduce twist...

Stiffness Coefficients of Mortise and Tenon Joints used on Wooden Window Profiles

Directory of Open Access Journals (Sweden)

Milan Podlena

2016-04-01

Full Text Available Samples of corner joints of wooden rectangular windows, with widths of 78 and 92 mm, were used to determine the stiffness of tenon and mortise joints. Two series of samples were loaded statically in the angular plane of compression and tension, so that the bending moment could be derived. The objective of the experiment was to determine the existing correlations between the stiffness in maximum strength and the stiffness in the elastic area for both types of tests. After strength tests were carried out, the annual ring width of the samples was measured to determine whether this factor affects the stiffness of the joints. The results showed that there was a relatively strong correlation between the stiffness in the elastic area and the maximum load. A two-factor analysis of variance confirmed that the type of load did not affect the stiffness of the joint, but the type of joint (width does significantly affect the stiffness. Therefore, the width of annual rings was positively correlated with the stiffness of the joints.

Mobilização do osso pisiforme no tratamento da neuropraxia do nervo ulnar no canal de Guyon: relato de caso Pisiform bone mobilization for treating ulnar nerve neuropraxia at Guyon's canal: case report

Directory of Open Access Journals (Sweden)

Júlio Guilherme Silva

2009-12-01

Full Text Available As neuropraxias do nervo ulnar são lesões bastante freqüentes que provocam efeitos deletérios, como diminuição de força muscular e parestesias; geralmente ocorrem no nível do epicôndilo medial e do túnel ulnar (canal de Guyon. São escassos os relatos referentes a técnicas de terapia manual para compressões do nervo ulnar no canal de Guyon. Este trabalho relata o uso da técnica de mobilização do pisiforme na compressão do nervo ulnar no canal de Guyon de um homem que sofreu luxação do punho direito aos 8 anos e, aos 25, queixava-se de um deficit para adução do dedo mínimo, que atrapalhava a realização de algumas atividades de vida diária. O paciente foi submetido a uma única sessão de mobilização articular do pisiforme. Após a aplicação da técnica, o sinal positivo do teste foi eliminado, restabelecendo-se a função de adução do 5o dedo. Embora carecendo de maior fundamentação teórica, pode-se afirmar que a técnica usada, de mobilização articular do osso pisiforme, é eficaz para melhora do quadro de paresia por neuropraxia do nervo ulnar no canal de Guyon.A common ulnar nerve neuropraxia is lesion that may result in muscle strength decrease and/or paresthesia; it usually takes place at medial epicondyle level and the ulnar tunnel (Guyon's canal. Studies on manual therapy techniques for ulnar nerve compression in Guyon's canal are scarce. This paper reports the use of a technique of pisiform bone mobilization for relieving ulnar nerve compression in Guyon's canal, in a man who had suffered a luxation of the right wrist at the age of 8 and, at 25, complained of adduction deficit of the fifth finger that interfered in his daily life activities. He was submitted to one session of pisiform mobilization; after the session, the positive test sign was eliminated, thus restoring the fifth finger function. Though lacking further grounding, it may be said that the technique used, of mobilizing the pisiform bone

Use of Guided Acoustic Waves to Assess the Effects of Thermal-Mechanical Cycling on Composite Stiffness

Science.gov (United States)

Seale, Michael D.; Madaras, Eric I.

2000-01-01

The introduction of new, advanced composite materials into aviation systems requires it thorough understanding of the long-term effects of combined thermal and mechanical loading. As part of a study to evaluate the effects of thermal-mechanical cycling, it guided acoustic (Lamb) wave measurement system was used to measure the bending and out-of-plane stiffness coefficients of composite laminates undergoing thermal-mechanical loading. The system uses a pulse/receive technique that excites an antisymmetric Lamb mode and measures the time-of-flight over a wide frequency range. Given the material density and plate thickness, the bending and out-of-plane shear stiffnesses are calculated from a reconstruction of the velocity dispersion curve. A series of 16 and 32-ply composite laminates were subjected to it thermal-mechanical loading profile in load frames equipped with special environmental chambers. The composite systems studied were it graphite fiber reinforced amorphous thermoplastic polyimide and it graphite fiber reinforced bismaleimide thermoset. The samples were exposed to both high and low temperature extremes its well as high and low strain profiles. The bending and out-of-plane stiffnesses for composite sample that have undergone over 6,000 cycles of thermal-mechanical loading are reported. The Lamb wave generated elastic stiffness results have shown decreases of up to 20% at 4,936 loading cycles for the graphite/thermoplastic samples and up to 64% at 4,706 loading cycles for the graphite/thermoset samples.

A comparison of 3-D computed tomography versus 2-D radiography measurements of ulnar variance and ulnolunate distance during forearm rotation.

Science.gov (United States)

Kawanishi, Y; Moritomo, H; Omori, S; Kataoka, T; Murase, T; Sugamoto, K

2014-06-01

Positive ulnar variance is associated with ulnar impaction syndrome and ulnar variance is reported to increase with pronation. However, radiographic measurement can be affected markedly by the incident angle of the X-ray beam. We performed three-dimensional (3-D) computed tomography measurements of ulnar variance and ulnolunate distance during forearm rotation and compared these with plain radiographic measurements in 15 healthy wrists. From supination to pronation, ulnar variance increased in all cases on the radiographs; mean ulnar variance increased significantly and mean ulnolunate distance decreased significantly. However on 3-D imaging, ulna variance decreased in 12 cases on moving into pronation and increased in three cases; neither the mean ulnar variance nor mean ulnolunate distance changed significantly. Our results suggest that the forearm position in which ulnar variance increased varies among individuals. This may explain why some patients with ulnar impaction syndrome complain of wrist pain exacerbated by forearm supination. It also suggests that standard radiographic assessments of ulnar variance are unreliable. © The Author(s) 2013.

Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members’ Joints

Directory of Open Access Journals (Sweden)

Gocál Jozef

2014-12-01

Full Text Available The paper deals with the real behaviour of the riveted steel railway bridge deck members’ connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

Lamb Wave Stiffness Characterization of Composites Undergoing Thermal-Mechanical Aging

Science.gov (United States)

Seale, Michael D.; Madaras, Eric I.

2004-01-01

The introduction of new, advanced composite materials into aviation systems requires a thorough understanding of the long term effects of combined thermal and mechanical loading upon those materials. Analytical methods investigating the effects of intense thermal heating combined with mechanical loading have been investigated. The damage mechanisms and fatigue lives were dependent on test parameters as well as stress levels. Castelli, et al. identified matrix dominated failure modes for out-of-phase cycling and fiber dominated damage modes for in-phase cycling. In recent years, ultrasonic methods have been developed that can measure the mechanical stiffness of composites. To help evaluate the effect of aging, a suitably designed Lamb wave measurement system is being used to obtain bending and out-of-plane stiffness coefficients of composite laminates undergoing thermal-mechanical loading. The system works by exciting an antisymmetric Lamb wave and calculating the velocity at each frequency from the known transducer separation and the measured time-of-flight. The same peak in the waveforms received at various distances is used to measure the time difference between the signals. The velocity measurements are accurate and repeatable to within 1% resulting in reconstructed stiffness values repeatable to within 4%. Given the material density and plate thickness, the bending and out-of-plane shear stiffnesses are calculated from a reconstruction of the dispersion curve. A mechanical scanner is used to move the sensors over the surface to map the time-of-flight, velocity, or stiffnesses of the entire specimen. Access to only one side of the material is required and no immersion or couplants are required because the sensors are dry coupled to the surface of the plate. In this study, the elastic stiffnesses D(sub 11), D(sub 22), A(sub 44), and A(sub 55) as well as time-of-flight measurements for composite samples that have undergone combined thermal and mechanical aging for

Motor branches of the ulnar nerve to the forearm: an anatomical study and guidelines for selective neurectomy.

Science.gov (United States)

Paulos, Renata; Leclercq, Caroline

2015-11-01

Precise knowledge of motor nerve branches is critical to plan selective neurectomies for the treatment of spastic limbs. Our objective is to describe the muscular branching pattern of the ulnar nerve in the forearm and suggest an ideal surgical approach for selective neurectomy of the flexor carpi ulnaris. The ulnar nerve was dissected under loop magnification in 20 upper limbs of fresh frozen cadavers and its branches to the flexor carpi ulnaris muscle (FCU) and to the flexor digitorum profundus muscle (FDP) were quantified. We measured their diameter, length and distance between their origin and the medial epicondyle. The point where the ulnar artery joined the nerve was observed. The position in which the ulnar nerve gave off each branch was noted (ulnar, posterior or radial) and the Martin-Gruber connection, when present, had its origin observed and its diameter measured. The ulnar nerve gave off two to five muscular branches, among which, one to four to the FCU and one or two to the FDP. In all cases, the first branch was to the FCU. It arose on average 1.4 cm distal to the epicondyle, but in four specimens it arose above or at the level of the medial epicondyle (2.0 cm above in one case, 1.5 cm above in two cases, and at the level of the medial epicondyle in one). The first branch to the FDP arose on average 5.0 cm distal to the medial epicondyle. All the branches to FDP but one arose from the radial aspect of the ulnar nerve. A Martin-Gruber connection was present in nine cases. All motor branches arose in the proximal half of the forearm and the ulnar nerve did not give off branches distal to the point where it was joined by the ulnar artery. The number of motor branches of the ulnar nerve to the FCU varies from 2 to 4. An ideal approach for selective neurectomy of the FCU should start 4 cm above the medial epicondyle, and extend distally to 50% of the length of the forearm or just to the point where the ulnar artery joins the nerve.

Bending Characteristics of Foldable Touch Display Panel with a Protection Structure Design

Directory of Open Access Journals (Sweden)

Hsien-Chie Cheng

2015-01-01

Full Text Available The study proposes and demonstrates an enhancement of a touch display panel (TDP through a polymer-based protection structure to achieve higher bendability and reliability. The bending performance of the TDP without or with the protection structure designs is addressed using three-dimensional geometry-nonlinear finite element analysis and mechanical testing. The elastic properties of the components in the TDP structure are derived from nanoindentation and uniaxial tensile/compressive testing. The calculated results are compared with each other and also against the experimental bending fatigue test data. At last, a design guideline and optimal factor setting for enhanced bending performance are sought through parametric FE analysis and Taguchi experimental design, respectively. The optimal design is compared with the original in terms of bending stress. The simulation results show that bending would create significant tensile and compressive bending stresses on the indium tin oxide/dielectric layers, which are the main cause of several commonly observed failures, such as thin film cracking and delamination, in a thin rigid film coating on a thick compliant substrate. It also turns out that a substrate with a lower stiffness has a better mechanical stability against bending stress.

Clinical bending of nickel titanium wires

Directory of Open Access Journals (Sweden)

Stephen Chain

2015-01-01

Full Text Available Since the evolution and the involvement of Nickel Titanium wires in the field of Orthodontics. The treatment plan has evolved with the use of low force Nickel Titanium wires. Because of their high springback, low stiffness, they are the key initial wires in leveling and alignment but have poor formability. Since poor formability limits its ability to create variable arch forms thus; limits the form of treatment. We have devised a method to bend the Nickel Titanium wires to help in our inventory but also customized the wire according to the treatment.

Identification of cation-binding sites on actin that drive polymerization and modulate bending stiffness

Science.gov (United States)

Kang, Hyeran; Bradley, Michael J.; McCullough, Brannon R.; Pierre, Anaëlle; Grintsevich, Elena E.; Reisler, Emil; De La Cruz, Enrique M.

2012-01-01

The assembly of actin monomers into filaments and networks plays vital roles throughout eukaryotic biology, including intracellular transport, cell motility, cell division, determining cellular shape, and providing cells with mechanical strength. The regulation of actin assembly and modulation of filament mechanical properties are critical for proper actin function. It is well established that physiological salt concentrations promote actin assembly and alter the overall bending mechanics of assembled filaments and networks. However, the molecular origins of these salt-dependent effects, particularly if they involve nonspecific ionic strength effects or specific ion-binding interactions, are unknown. Here, we demonstrate that specific cation binding at two discrete sites situated between adjacent subunits along the long-pitch helix drive actin polymerization and determine the filament bending rigidity. We classify the two sites as “polymerization” and “stiffness” sites based on the effects that mutations at the sites have on salt-dependent filament assembly and bending mechanics, respectively. These results establish the existence and location of the cation-binding sites that confer salt dependence to the assembly and mechanics of actin filaments. PMID:23027950

Differentiating C8–T1 Radiculopathy from Ulnar Neuropathy: A Survey of 24 Spine Surgeons

Science.gov (United States)

Stoker, Geoffrey E.; Kim, Han Jo; Riew, K. Daniel

2013-01-01

Study Design Questionnaire. Objective To evaluate the ability of spine surgeons to distinguish C8–T1 radiculopathies from ulnar neuropathy. Methods Twenty-four self-rated “experienced” cervical spine surgeons completed a questionnaire with the following items. (1) If the ulnar nerve is cut at the elbow, which of the following would be numb: ulnar forearm, small and ring fingers; only the ulnar forearm; only the small and ring fingers; or none of the above? (2) Which of the following muscles are weak with C8–T1 radiculopathies but intact with ulnar neuropathy at the elbow: flexor digiti minimi brevis, flexor pollicis brevis, abductor digiti minimi, abductor pollicis brevis, adductor pollicis, opponens digiti minimi, opponens pollicis, medial lumbricals, lateral lumbricals, dorsal interossei, palmar interossei? Results Fifteen of 24 surgeons (63%) correctly answered the first question—that severing the ulnar nerve results in numbness of the fifth and fourth fingers. None correctly identified all four nonulnar, C8–T1-innervated options in the second question without naming additional muscles. Conclusion The ulnar nerve provides sensation to the fourth and fifth fingers and medial border of the hand. The medial antebrachial cutaneous nerve provides sensation to the medial forearm. The ulnar nerve innervates all intrinsic hand muscles, except the abductor and flexor pollicis brevis, opponens pollicis, and lateral two lumbricals, which are innervated by C8 and T1 via the median nerve. By examining these five muscles, one can clinically differentiate cubital tunnel syndrome from C8–T1 radiculopathies. Although all participants considered themselves to be experienced cervical spine surgeons, this study reveals inadequate knowledge regarding the clinical manifestations of C8–T1 radiculopathies and cubital tunnel syndrome. PMID:24494175

Ulnar nerve entrapment in a French horn player.

Science.gov (United States)

Hoppmann, R A

1997-10-01

Nerve entrapment syndromes are frequent among musicians. Because of the demands on the musculoskeletal system and the great agility needed to per-form, musicians often present with vague complaints early in the course of entrapment, which makes the diagnosis a challenge for the clinician. Presented here is such a case of ulnar nerve entrapment at the left elbow of a French horn player. This case points out some of the difficulties in establishing a diagnosis of nerve entrapment in musicians. It also supports the theory that prolonged elbow flexion and repetitive finger movement contribute to the development of ulnar entrapment at the elbow. Although surgery is not required for most of the musculoskeletal problems of musicians, release of an entrapped nerve refractory to conservative therapy may be career-saving for the musician.

A eutectic-alloy-infused soft actuator with sensing, tunable degrees of freedom, and stiffness properties

Science.gov (United States)

Hao, Yufei; Wang, Tianmiao; Xie, Zhexin; Sun, Wenguang; Liu, Zemin; Fang, Xi; Yang, Minxuan; Wen, Li

2018-02-01

This paper presents a soft actuator embedded with two types of eutectic alloys which enable sensing, tunable mechanical degrees of freedom (DOF), and variable stiffness properties. To modulate the stiffness of the actuator, we embedded a low melting point alloy (LMPA) in the bottom portion of the soft actuator. Different sections of the LMPA could be selectively melted by the Ni-Cr wires twined underneath. To acquire the curvature information, EGaIn (eutectic gallium indium) was infused into a microchannel surrounding the chambers of the soft actuator. Systematic experiments were performed to characterize the stiffness, tunable DOF, and sensing the bending curvature. We found that the average bending force and elasticity modulus could be increased about 35 and 4000 times, respectively, with the LMPA in a solid state. The entire LMPA could be melted from a solid to a liquid state within 12 s. In particular, up to six different motion patterns could be achieved under each pneumatic pressure of the soft actuator. Furthermore, the kinematics of the actuator under different motion patterns could be obtained by a mathematical model whose input was provided by the EGaIn sensor. For demonstration purposes, a two-fingered gripper was fabricated to grasp various objects by adjusting the DOF and mechanical stiffness.

Complete dislocation of the ulnar nerve at the elbow: a protective effect against neuropathy?

Science.gov (United States)

Leis, A Arturo; Smith, Benn E; Kosiorek, Heidi E; Omejec, Gregor; Podnar, Simon

2017-08-01

Recurrent complete ulnar nerve dislocation has been perceived as a risk factor for development of ulnar neuropathy at the elbow (UNE). However, the role of dislocation in the pathogenesis of UNE remains uncertain. We studied 133 patients with complete ulnar nerve dislocation to determine whether this condition is a risk factor for UNE. In all, the nerve was palpated as it rolled over the medial epicondyle during elbow flexion. Of 56 elbows with unilateral dislocation, UNE localized contralaterally in 17 elbows (30.4%) and ipsilaterally in 10 elbows (17.9%). Of 154 elbows with bilateral dislocation, 26 had UNE (16.9%). Complete dislocation decreased the odds of having UNE by 44% (odds ratio = 0.475; P =  0.028), and was associated with less severe UNE (P = 0.045). UNE occurs less frequently and is less severe on the side of complete dislocation. Complete dislocation may have a protective effect on the ulnar nerve. Muscle Nerve 56: 242-246, 2017. © 2016 Wiley Periodicals, Inc.

A study on operative findings and pathogenic factors in ulnar neuropathy at the elbow.

Science.gov (United States)

Kojima, T; Kurihara, K; Nagano, T

1979-01-01

A study was made of operative findings obtained in 44 cases of ulnar nerve neuropathy at the elbow in an attempt to help elucidate the pathogenetic factors for the condition. Distinction must be made between Lig. epitrochleo-anconeum or a ligament-like thickening at the same site and the tendinous arch of M. flexor carpi ulnaris. These 2 sites constitute the entrapment points for the condition. A thick tendinous arch, Lig. epitrochleo-anconeum of M. anconeus epitrochlearis deters the ulnar nerve from being mobile, thereby contributing to the development of neuropathy with trauma acting as a precipitating factor. Dislocation of the ulnar nerve cannot be considered a factor of major etiologic significance. An important part is played by the tendinous arch in the pathogenesis of neuropathy, regardless of whether it is in association with ganglion, osteochondromatosis or osteoarthritis. In surgery for ulnar neuropathy decompression of the nerve is of primary necessity. Division of the tendinous arch is mandatory. Medial epicondylectomy may be added as required.

Ulnar nerve entrapment complicating radial head excision

Directory of Open Access Journals (Sweden)

Kevin Parfait Bienvenu Bouhelo-Pam

Full Text Available Introduction: Several mechanisms are involved in ischemia or mechanical compression of ulnar nerve at the elbow. Presentation of case: We hereby present the case of a road accident victim, who received a radial head excision for an isolated fracture of the radial head and complicated by onset of cubital tunnel syndrome. This outcome could be the consequence of an iatrogenic valgus of the elbow due to excision of the radial head. Hitherto the surgical treatment of choice it is gradually been abandoned due to development of radial head implant arthroplasty. However, this management option is still being performed in some rural centers with low resources. Discussion: The radial head plays an important role in the stability of the elbow and his iatrogenic deformity can be complicated by cubital tunnel syndrome. Conclusion: An ulnar nerve release was performed with favorable outcome. Keywords: Cubital tunnel syndrome, Peripheral nerve palsy, Radial head excision, Elbow valgus

The potential complications of open carpal tunnel release surgery to the ulnar neurovascular bundle and its branches: A cadaveric study.

Science.gov (United States)

Boughton, O; Adds, P J; Jayasinghe, J A P

2010-07-01

This study investigated the ulnar artery and the ulnar nerve and its branches in the palm to assess how frequently they may be at risk of damage during open carpal tunnel release surgery. Twenty-one formalin-embalmed cadaveric hands were dissected, and the proximity of the ulnar neurovascular bundle to two different lines of incision, the 3rd and 4th interdigital web space axis and the ring finger axis, was assessed and compared. It was found that an incision in the latter (ring finger) axis put the ulnar artery at risk in 12 of 21 specimens, whereas an incision in the former axis (3rd/4th interdigital web space) put the ulnar artery at risk in only two specimens. In 15 hands at least one structure (the ulnar artery or a branch of the ulnar nerve) was at risk in the ring finger axis compared to only seven hands in the axis of the 3rd/4th interdigital web space. We conclude that the ulnar artery and branches of the ulnar nerve are at increased risk of damage with an incision in the axis of the ring finger. The importance of using a blunt dissection technique under direct vision during surgery to identify and preserve these structures and median nerve branches is emphasized. (c) 2010 Wiley-Liss, Inc.

Clinical effects of internal fixation for ulnar styloid fractures associated with distal radius fractures: A matched case-control study.

Science.gov (United States)

Sawada, Hideyoshi; Shinohara, Takaaki; Natsume, Tadahiro; Hirata, Hitoshi

2016-11-01

Ulnar styloid fractures are often associated with distal radius fractures. However, controversy exists regarding whether to treat ulnar styloid fractures. This study aimed to evaluate clinical effects of internal fixation for ulnar styloid fractures after distal radius fractures were treated with the volar locking plate system. We used prospectively collected data of distal radius fractures. 111 patients were enrolled in this study. A matched case-control study design was used. We selected patients who underwent fixation for ulnar styloid fractures (case group). Three control patients for each patient of the case group were matched on the basis of age, sex, and fracture type of distal radius fractures from among patients who did not undergo fixation for ulnar styloid fractures (control group). The case group included 16 patients (7 men, 9 women; mean age: 52.6 years; classification of ulnar styloid fractures: center, 3; base, 11; and proximal, 2). The control group included 48 patients (15 men, 33 women; mean age: 61.1 years; classification of ulnar styloid fractures: center, 10; base, 31; and proximal, 7). For radiographic examination, the volar tilt angle, radial inclination angle, and ulnar variance length were measured, and the union of ulnar styloid fractures was judged. For clinical examination, the range of motions, grip strength, Hand20 score, and Numeric Rating Scale score were evaluated. There was little correction loss for each radiological parameter of fracture reduction, and these parameters were not significantly different between the groups. The bone-healing rate of ulnar styloid fractures was significantly higher in the case group than in the control group, but the clinical results were not significantly different. We revealed that there was no need to fix ulnar styloid fractures when distal radius fractures were treated via open reduction and internal fixation with a volar locking plate system. Copyright © 2016 The Japanese Orthopaedic Association

Perforator anatomy of the ulnar forearm fasciocutaneous flap.

Science.gov (United States)

Mathy, Jon A; Moaveni, Zachary; Tan, Swee T

2012-08-01

The ulnar forearm fasciocutaneous flap (UFFF) is a favourable alternative to the radial forearm flap when thin and pliable tissue is required. The precise anatomy of the cutaneous perforators of UFFF has not been previously reported. The position of cutaneous perforators>0.5 mm was recorded while raising 52 consecutive free UFFFs in 51 patients at our Centre. Three (6%) UFFFs in two patients demonstrated direct cutaneous supply through a superficial ulnar artery, a known anatomic variance. There was no cutaneous perforator>0.5 mm in one flap. Among the remaining 48 dissections, an average of 3 (range, 1-6) cutaneous perforators were identified. Ninety-four percent of these forearms demonstrated at least one perforator>0.5 mm within 3 cm, and all had at least one perforator within 6 cm of the midpoint of the forearm. Proximal perforators were more likely to be musculo-cutaneous through the edge of flexor carpi ulnaris or flexor digitorum superficialis, while mid- to distal perforators were septo-cutaneous. UFFF skin paddle designed to overlie an area within 3 cm of the midpoint between the medial epicondyle and the pisiform is most likely to include at least one cutaneous perforator from the ulnar artery, without a need for intra-operative skin island adjustment. This novel anatomic finding and other practical generalisations are discussed to facilitate successful elevation of UFFF. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Elastic Modulus of Foamcrete in Compression and Bending at Elevated Temperatures

Directory of Open Access Journals (Sweden)

Md Azree Othuman Mydin

2012-09-01

Full Text Available This paper will presents the experimental results that have been performed to examine and characterize the mechanical properties of foamcrete at elevated temperatures. Foamcrete of 650 and 1000 kg/m 3 density were cast and tested under compression and bending. The tests were done at room temperature, 100, 200, 300, 400, 500, and 600°C. The results of this study consistently demonstrated that the loss in stiffness for cement based material like foamcrete at elevated temperatures occurs predominantly after about 95°C, regardless of density. This indicates that the primary mechanism causing stiffness degradation is microcracking, which occurs as water expands and evaporates from the porous body. As expected, reducing the density of LFC reduces its strength and stiffness. However, for LFC of different densities, the normalised strength-temperature and stiffnesstemperature relationships are very similar.

TOPOGRAFÍA INTRANEURAL DE LA RAMA PROFUNDA DEL NERVIO ULNAR EN EL ANTEBRAZO DISTAL: ESTUDIO CADAVÉRICO. Intraneural topography of the deep branch of the ulnar nerve in the distal forearm: cadaveric study.

Directory of Open Access Journals (Sweden)

Joaquín García Pisón

2016-07-01

Full Text Available Objetivo: estudiar la topografía intraneural de la rama profunda del nervio ulnar (RPNU en el antebrazo distal en vistas a su identificación mediante disección intraneural mínima durante la transferencia del nervio del pronador cuadrado (NPC a la RPNU. Materiales y métodos: En 15 antebrazos cadavéricos se fijó el paquete vasculonervioso ulnar a los planos musculares profundos cada un centímetro tomando como referencia el hueso pisiforme. Se disecó en sentido proximal la RPNU bajo microscopio quirúrgico (Olympus OME, 4-20x y se registró su posición intraneural en base a una división en cuadrantes. Se midió la distancia desde el origen de la rama cutánea dorsal (RCD del nervio ulnar al pisiforme y se registró su relación intraneural con la RPNU. Resultados: La RPNU se individualizó hasta 69mm (41-94 proximal al hueso pisiforme, ubicándose en el cuadrante posteromedial del nervio ulnar en el 78% (67-87, el 93% (92-93 y el 100% de los casos entre los 0-2, 3-6 y 7-9 centímetros, respectivamente. La distancia pisiforme-RCD fue de 63mm (52-83. En 11 miembros la disección de la RPNU se extendió proximalmente al origen de la RCD, ubicándose siempre entre esta última y la rama superficial del nervio ulnar. Conclusiones: La topografía intraneural de la RPNU en el sitio óptimo para su sección en vistas a su anastomosis con el NPC es predecible en la mayoría de los casos, lo que confirma la viabilidad de su identificación precisa mediante disección intraneural mínima.  Objective: to assess the intraneural anatomy of the deep branch of the ulnar nerve (DBUN in the distal forearm in reference to its identification by means of minimal intraneural dissection during pronator quadratus nerve to DBUN transfers. Materials and methods: In 15 cadaveric forearms the ulnar neurovascular bundle was identified and attached to the subjacent muscles every one centimeter. Pisiform bone was used as reference. Intraneural proximal dissection of

Osteosynthesis for symptomatic ulnar styloid nonunion

International Nuclear Information System (INIS)

Kajiwara, Ryoji; Kimori, Kenji; Kawagoe, Hiroyuki; Tsuge, Kenya; Ikuta, Yosikazu

2008-01-01

We reviewed cases of osteosynthesis for symptomatic ulnar styloid nonunion. Since 1998, 13 cases of ulnar styloid nonunion have been treated by osteosynthesis. The patients were 10 men and 3 women, with a mean age of 27 years (range 11-65). The nonunion site was located in the middle in one case, in the base in 8 cases, and in the epiphyseal region in 4 cases. Osteosynthesis was performed with tension band wiring in all cases, and cancellous bone graft was performed in 12 of 13 cases. Distal radioulnar joint (DRUJ) instability was found by radiograph or CT in four cases; in two of these, osteosynthesis alone did not improve DRUJ instability and additional DRUJ stabilization was performed. One patient whose treatment failed to correct nonunion did not seek further treatment. In another case, an additional surgery was performed 1 week after the initial surgery to correct displacement of the fragment. The mean follow-up period was 15 months (range 8-45 months). According to Hauck's criteria, final pain was evaluated as excellent in nine cases, good in three cases, including the case resulting in nonunion, and fair in one case. (author)

Radial and ulnar bursae of the wrist: cadaveric investigation of regional anatomy with ultrasonographic-guided tenography and MR imaging

International Nuclear Information System (INIS)

Aguiar, R.O.C.; Gasparetto, E.L.; Marchiori, E.; Escuissato, D.L.; Trudell, D.J.; Haghighi, P.; Resnik, D.

2006-01-01

To demonstrate the anatomy of the radial and ulnar bursae of the wrist using MR and US images. Ultrasonographic-guided tenography of the tendon sheath of flexor pollicis longus (FPL) and the common tendon sheath of the flexor digitorum of the fifth digit (FD5) of ten cadaveric hands was performed, followed by magnetic resonance imaging and gross anatomic correlation. Patterns of communication were observed between these tendon sheaths and the radial and ulnar bursae of the wrist. The tendon sheath of the FPL communicated with the radial bursa in 100% (10/10) of cases, and the tendon sheath of the FD5 communicated with the ulnar bursa in 80% (8/10). Communication of the radial and ulnar bursae was evident in 100% (10/10), and presented an ''hourglass'' configuration in the longitudinal plane. The ulnar and radial bursae often communicate. The radial bursa communicates with the FPL tendon sheath, and the ulnar bursa may communicate with the FD5 tendon sheath

The study of stiffness modulus values for AC-WC pavement

Science.gov (United States)

Lubis, AS; Muis, Z. A.; Iskandar, T. D.

2018-02-01

One of the parameters of the asphalt mixture in order for the strength and durability to be achieved as required is the stress-and-strain showing the stiffness of a material. Stiffness modulus is a very necessary factor that will affect the performance of asphalt pavements. If the stiffness modulus value decreases there will be a cause of aging asphalt pavement crack easily when receiving a heavy load. The high stiffness modulus asphalt concrete causes more stiff and resistant to bending. The stiffness modulus value of an asphalt mixture material can be obtained from the theoretical (indirect methods) and laboratory test results (direct methods). For the indirect methods used Brown & Brunton method, and Shell Bitumen method; while for the direct methods used the UMATTA tool. This study aims to determine stiffness modulus values for AC-WC pavement. The tests were conducted in laboratory that used 3 methods, i.e. Brown & Brunton Method, Shell Bitumen Method and Marshall Test as a substitute tool for the UMATTA tool. Hotmix asphalt made from type AC-WC with pen 60/70 using a mixture of optimum bitumen content was 5.84% with a standard temperature variation was 60°C and several variations of temperature that were 30, 40, 50, 70 and 80°C. The stiffness modulus value results obtained from Brown & Brunton Method, Shell Bitumen Method and Marshall Test which were 1374,93 Mpa, 235,45 Mpa dan 254,96 Mpa. The stiffness modulus value decreases with increasing temperature of the concrete asphalt. The stiffness modulus value from the Bitumen Shell method and the Marshall Test has a relatively similar value.The stiffness modulus value from the Brown & Brunton method is greater than the Bitumen Shell method and the Marshall Test, but can not measure the stiffness modulus value at temperature above 80°C.

Morphology and morphometry of the ulnar head of the pronator teres muscle in relation to median nerve compression at the proximal forearm.

Science.gov (United States)

Gurses, I A; Altinel, L; Gayretli, O; Akgul, T; Uzun, I; Dikici, F

2016-12-01

The pronator syndrome is a rare compression neuropathy of the median nerve. Ulnar head of the pronator teres muscle may cause compression at proximal forearm. Detailed morphologic and morphometric studies on the anatomy of the ulnar head of pronator teres is scarce. We dissected 112 forearms of fresh cadavers. We evaluated the morphology and morphometry of the ulnar head of pronator teres muscle. The average ulnar head width was 16.3±8.2mm. The median nerve passed anterior to the ulnar head at a distance of 50.4±10.7mm from the interepicondylar line. We classified the morphology of the ulnar head into 5 types. In type 1, the ulnar head was fibromuscular in 60 forearms (53.6%). In type 2, it was muscular in 23 forearms (20.5%). In type 3, it was just a fibrotic band in 18 forearms (16.1%). In type 4, it was absent in 9 forearms (8%). In type 5, the ulnar head had two arches in 2 forearms (1.8%). In 80 forearms (71.5%: types 1, 3, and 5), the ulnar head was either fibromuscular or a fibrotic band. Although the pronator syndrome is a rare compression syndrome, the ulnar head of pronator teres is reported as the major cause of entrapment in the majority of the cases. The location of the compression of the median nerve in relation to the ulnar head of pronator teres muscle and the morphology of the ulnar head is important for open or minimally-invasive surgical treatment. Sectional study. Basic science study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Evaluation on Bending Properties of Biomaterial GUM Metal Meshed Plates for Bone Graft Applications

Science.gov (United States)

Suzuki, Hiromichi; He, Jianmei

2017-11-01

There are three bone graft methods for bone defects caused by diseases such as cancer and accident injuries: Autogenous bone grafts, Allografts and Artificial bone grafts. In this study, meshed GUM Metal plates with lower elasticity, high strength and high biocompatibility are introduced to solve the over stiffness & weight problems of ready-used metal implants. Basic mesh shapes are designed and applied to GUM Metal plates using 3D CAD modeling tools. Bending properties of prototype meshed GUM Metal plates are evaluated experimentally and analytically. Meshed plate specimens with 180°, 120° and 60° axis-symmetrical types were fabricated for 3-point bending tests. The pseudo bending elastic moduli of meshed plate specimens obtained from 3-point bending test are ranged from 4.22 GPa to 16.07 GPa, within the elasticity range of natural cortical bones from 2.0 GPa to 30.0 GPa. Analytical approach method is validated by comparison with experimental and analytical results for evaluation on bending property of meshed plates.

Effect of crosslink torsional stiffness on elastic behavior of semiflexible polymer networks

Science.gov (United States)

Hatami-Marbini, H.

2018-02-01

Networks of semiflexible filaments are building blocks of different biological and structural materials such as cytoskeleton and extracellular matrix. The mechanical response of these systems when subjected to an applied strain at zero temperature is often investigated numerically using networks composed of filaments, which are either rigidly welded or pinned together at their crosslinks. In the latter, filaments during deformation are free to rotate about their crosslinks while the relative angles between filaments remain constant in the former. The behavior of crosslinks in actual semiflexible networks is different than these idealized models and there exists only partial constraint on torques at crosslinks. The present work develops a numerical model in which two intersecting filaments are connected to each other by torsional springs with arbitrary stiffness. We show that fiber networks composed of rigid and freely rotating crosslinks are the limiting case of the present model. Furthermore, we characterize the effects of stiffness of crosslinks on effective Young's modulus of semiflexible networks as a function of filament flexibility and crosslink density. The effective Young's modulus is determined as a function of the mechanical properties of crosslinks and is found to vanish for networks composed of very weak torsional springs. Independent of the stiffness of crosslinks, it is found that the effective Young's modulus is a function of fiber flexibility and crosslink density. In low density networks, filaments primarily bend and the effective Young's modulus is much lower than the affine estimate. With increasing filament bending stiffness and/or crosslink density, the mechanical behavior of the networks becomes more affine and the stretching of filaments depicts itself as the dominant mode of deformation. The torsional stiffness of the crosslinks significantly affects the effective Young's modulus of the semiflexible random fiber networks.

Use of locking compression plates in ulnar fractures of 18 horses.

Science.gov (United States)

Jacobs, Carrie C; Levine, David G; Richardson, Dean W

2017-02-01

To describe the outcome, clinical findings, and complications associated with the use of the locking compression plate (LCP) for various types of ulnar fractures in horses. Retrospective case series. Client owned horses (n = 18). Medical records, radiographs, and follow-up for horses having an ulnar fracture repaired using at least 1 LCP were reviewed. Fifteen of 18 horses had fractures of the ulna only, and 3 horses had fractures of the ulna and proximal radius. All 18 horses were discharged from the hospital. Complications occurred in 5 horses; incisional infection (n = 4, 22%), implant-associated infection (n = 2, 11%), and colic (n = 1, 6%). Follow-up was available for all horses at a range of 13-120 months and 15 horses (83%) were sound for their intended purpose and 3 horses (17%) were euthanatized. One horse was euthanatized for complications associated with original injury and surgery. The LCP is a viable method of internal fixation for various types of ulnar fractures, with most horses in this series returning to soundness. © 2017 The American College of Veterinary Surgeons.

Ganglion Cyst Associated with Triangular Fibrocartilage Complex Tear That Caused Ulnar Nerve Compression

Directory of Open Access Journals (Sweden)

Ugur Anil Bingol, MD

2015-03-01

Full Text Available Summary: Ganglions are the most frequently seen soft-tissue tumors in the hand. Nerve compression due to ganglion cysts at the wrist is rare. We report 2 ganglion cysts arising from triangular fibrocartilage complex, one of which caused ulnar nerve compression proximal to the Guyonʼs canal, leading to ulnar neuropathy. Ganglion cysts seem unimportant, and many surgeons refrain from performing a general hand examination.

The "hierarchical" Scratch Collapse Test for identifying multilevel ulnar nerve compression.

Science.gov (United States)

Davidge, Kristen M; Gontre, Gil; Tang, David; Boyd, Kirsty U; Yee, Andrew; Damiano, Marci S; Mackinnon, Susan E

2015-09-01

The Scratch Collapse Test (SCT) is used to assist in the clinical evaluation of patients with ulnar nerve compression. The purpose of this study is to introduce the hierarchical SCT as a physical examination tool for identifying multilevel nerve compression in patients with cubital tunnel syndrome. A prospective cohort study (2010-2011) was conducted of patients referred with primary cubital tunnel syndrome. Five ulnar nerve compression sites were evaluated with the SCT. Each site generating a positive SCT was sequentially "frozen out" with a topical anesthetic to allow determination of both primary and secondary ulnar nerve entrapment points. The order or "hierarchy" of compression sites was recorded. Twenty-five patients (mean age 49.6 ± 12.3 years; 64 % female) were eligible for inclusion. The primary entrapment point was identified as Osborne's band in 80 % and the cubital tunnel retinaculum in 20 % of patients. Secondary entrapment points were also identified in the following order in all patients: (1) volar antebrachial fascia, (2) Guyon's canal, and (3) arcade of Struthers. The SCT is useful in localizing the site of primary compression of the ulnar nerve in patients with cubital tunnel syndrome. It is also sensitive enough to detect secondary compression points when primary sites are sequentially frozen out with a topical anesthetic, termed the hierarchical SCT. The findings of the hierarchical SCT are in keeping with the double crush hypothesis described by Upton and McComas in 1973 and the hypothesis of multilevel nerve compression proposed by Mackinnon and Novak in 1994.

Perforator anatomy of the radial forearm free flap versus the ulnar forearm free flap for head and neck reconstruction.

Science.gov (United States)

Hekner, D D; Roeling, T A P; Van Cann, E M

2016-08-01

The aim of this study was to investigate the vascular anatomy of the distal forearm in order to optimize the choice between the radial forearm free flap and the ulnar forearm free flap and to select the best site to harvest the flap. The radial and ulnar arteries of seven fresh cadavers were injected with epoxy resin (Araldite) and the perforating arteries were dissected. The number of clinically relevant perforators from the radial and ulnar arteries was not significantly different in the distal forearm. Most perforators were located in the proximal half of the distal one third, making this part probably the safest location for flap harvest. Close to the wrist, i.e. most distally, there were more perforators on the ulnar side than on the radial side. The ulnar artery stained 77% of the skin surface area of the forearm, showing the ulnar forearm free flap to be more suitable than the radial forearm free flap for the restoration of large defects. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Ulnar nerve lesion at the wrist and sport: A report of 8 cases compared with 45 non-sport cases.

Science.gov (United States)

Seror, P

2015-04-01

Reporting clinical and electrodiagnostic characteristics of sport-related ulnar neuropathies at the wrist. Eight sport-related and 45 non-sport-related cases from 53 ulnar neuropathies at the wrist cases over 14 years. Sport-related ulnar neuropathies at the wrist cases were due to cycling (5 cases), kayaking (2 cases), and big-game fishing (1 case). No patient had sensory complaints in ulnar digits, and all had motor impairment. Conduction across the wrist with recording on the first dorsal interosseous muscle was impaired in all cases, with conduction block in 5. Two cyclists showed bilateral ulnar neuropathies at the wrist. All cases recovered within 2 to 6 months with sport discontinuation. Distal lesions of the deep motor branch were more frequent in sport- than non-sport-related cases. The 8 sport-related ulnar neuropathies at the wrist cases involved the deep motor branch. Conduction study to the first dorsal interosseous muscle across the wrist is the key to electrodiagnostics. Bilateral cases in cyclists does not require wrist imaging. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections.

Science.gov (United States)

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-06-18

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness.

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections

Directory of Open Access Journals (Sweden)

Francesco Morelli

2017-06-01

Full Text Available Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness.

Stabilization of the ulnar stump using modified Breen method after the Sauve-Kapandji procedure in rheumatoid wrist

International Nuclear Information System (INIS)

Tanino, Yoshihiko; Yabe, Yutaka; Yamauchi, Kenji; Ikegami, Hiroyasu; Ichikawa, Tooru

2006-01-01

We report on the utility of the modified Breen method in addition to the Sauve-Kapandji operation for the treatment of instability and pain in the proximal ulnar stump in rheumatoid arthrities (RA) wrist. We treated a total of 15 hands in 12 patients with disturbances due to instability and pain at the proximal ulnar stump. The average follow-up period was 47 months. We evaluated the range of motion, grip strength, radioulnar distance, and the radioulnar distance at the stump using CT during pronation, supination, and neutral positions of the forearm in 11 of the 15 operated hands. We observed that none of the patients showed any signs of pain at the proximal ulnar stump and no scallop sign was observed. In all the cases, the line connecting the center of the radial head to the proximal ulnar stump served as the axis of rotation for the forearm; this was confirmed by the CT images. We concluded that our operative method resulted in stabilization of the proximal ulnar stump and recovery of powerful grip without pain during forearm rotation. (author)

Skin-Inspired Hierarchical Polymer Architectures with Gradient Stiffness for Spacer-Free, Ultrathin, and Highly Sensitive Triboelectric Sensors.

Science.gov (United States)

Ha, Minjeong; Lim, Seongdong; Cho, Soowon; Lee, Youngoh; Na, Sangyun; Baig, Chunggi; Ko, Hyunhyub

2018-04-24

The gradient stiffness between stiff epidermis and soft dermis with interlocked microridge structures in human skin induces effective stress transmission to underlying mechanoreceptors for enhanced tactile sensing. Inspired by skin structure and function, we fabricate hierarchical nanoporous and interlocked microridge structured polymers with gradient stiffness for spacer-free, ultrathin, and highly sensitive triboelectric sensors (TESs). The skin-inspired hierarchical polymers with gradient elastic modulus enhance the compressibility and contact areal differences due to effective transmission of the external stress from stiff to soft layers, resulting in highly sensitive TESs capable of detecting human vital signs and voice. In addition, the microridges in the interlocked polymers provide an effective variation of gap distance between interlocked layers without using the bulk spacer and thus facilitate the ultrathin and flexible design of TESs that could be worn on the body and detect a variety of pressing, bending, and twisting motions even in humid and underwater environments. Our TESs exhibit the highest power density (46.7 μW/cm 2 ), pressure (0.55 V/kPa), and bending (∼0.1 V/°) sensitivities ever reported on flexible TESs. The proposed design of hierarchical polymer architectures for the flexible and wearable TESs can find numerous applications in next-generation wearable electronics.

Analysis of pipe mitred bends using beam models - by finite element method

International Nuclear Information System (INIS)

Salles, A.C.S.L. de.

1984-01-01

The formulation of a recently proposed displacement based straight pipe element for the analysis of pipe mitred bends is summarized in this work. The element kinematics includes axial, bending, torsional and ovalisation displacements, all varying cubically along the axis of the element. Interaction effects between angle adjoined straight pipe section are modeled including the appropriate additional strain terms in the stiffness matrix formulation and by using a penalty procedure to enforce continuity of pipe skin flexural rotations at the common helical edge. The element model capabilities are ilustrated in some sample analysis and the results are compared with other available experimental, analytical or more complex numerical models. (Author) [pt

Extension of elastic stiffness formula for leaf type holddown spring assembly

Energy Technology Data Exchange (ETDEWEB)

Song, Kee Nam; Kang, Heung Seok; Yoon, Kyung Ho; Kim, Hyung Kyu [Korea Atomic Energy Research Institute, Taejon (Korea)

1998-09-01

Based on the Euler beam theory and the strain energy method, an elastic stiffness formula of the holddown spring assembly consisting of several leaves was previously derived. The formula was known to be useful to estimate the elastic stiffness of the holddown spring assembly only with the geometric data and the material properties of the leaf. Recently, it was reported that the elastic stiffness from the formula deviated much from the test results as the number of leaves was increased. In this study, in order to resolve such an increasing deviation as the increasing number of leaves, the formula has been extended to be able to consider normal forces and friction forces acting on interfaces between the leaves. The elastic stiffness analysis on specimens of leaf type holddown springs has been carried out using the extended formula and the analysis results are compared with the test results. As a result of comparisons, it is found that the extended formula is able to evaluate the elastic stiffness of the holddown spring assembly within an error range of 10%, irrespective of the number of leaves. In addition, it is found that the effect of shear forces and axial forces on the elastic stiffness of the holddown spring assembly is only below 0.2% of the elastic stiffness, and therefore the greatest portion of the elastic stiffness of the holddown spring assembly is attributed to the bending moment. (author). 13 refs., 10 figs., 12 tabs.

Classification of ulnar triangular fibrocartilage complex tears. A treatment algorithm for Palmer type IB tears.

Science.gov (United States)

Atzei, A; Luchetti, R; Garagnani, L

2017-05-01

The classical definition of 'Palmer Type IB' triangular fibrocartilage complex tear, includes a spectrum of clinical conditions. This review highlights the clinical and arthroscopic criteria that enable us to categorize five classes on a treatment-oriented classification system of triangular fibrocartilage complex peripheral tears. Class 1 lesions represent isolated tears of the distal triangular fibrocartilage complex without distal radio-ulnar joint instability and are amenable to arthroscopic suture. Class 2 tears include rupture of both the distal triangular fibrocartilage complex and proximal attachments of the triangular fibrocartilage complex to the fovea. Class 3 tears constitute isolated ruptures of the proximal attachment of the triangular fibrocartilage complex to the fovea; they are not visible at radio-carpal arthroscopy. Both Class 2 and Class 3 tears are diagnosed with a positive hook test and are typically associated with distal radio-ulnar joint instability. If required, treatment is through reattachment of the distal radio-ulnar ligament insertions to the fovea. Class 4 lesions are irreparable tears due to the size of the defect or to poor tissue quality and, if required, treatment is through distal radio-ulnar ligament reconstruction with tendon graft. Class 5 tears are associated with distal radio-ulnar joint arthritis and can only be treated with salvage procedures. This subdivision of type IB triangular fibrocartilage complex tear provides more insights in the pathomechanics and treatment strategies. II.

Effect of long-term isometric training on core/torso stiffness.

Science.gov (United States)

Lee, Benjamin C Y; McGill, Stuart M

2015-06-01

Although core stiffness enhances athletic performance traits, controversy exists regarding the effectiveness of isometric vs. dynamic core training methods. This study aimed to determine whether long-term changes in stiffness can be trained, and if so, what is the most effective method. Twenty-four healthy male subjects (23 ± 3 years; 1.8 ± 0.06 m; 77.5 ± 10.8 kg) were recruited for passive and active stiffness measurements before and after a 6-week core training intervention. Twelve subjects (22 ± 2 years; 1.8 ± 0.08 m; 78.3 ± 12.3 kg) were considered naive to physical and core exercise. The other 12 subjects (24 ± 3 years; 1.8 ± 0.05 m; 76.8 ± 9.7 kg) were Muay Thai athletes (savvy). A repeated-measures design compared core training methods (isometric vs. dynamic, with a control group) and subject training experience (naive vs. savvy) before and after a 6-week training period. Passive stiffness was assessed on a "frictionless" bending apparatus and active stiffness assessed through a quick release mechanism. Passive stiffness increased after the isometric training protocol. Dynamic training produced a smaller effect, and as expected, there was no change in the control group. Active stiffness did not change in any group. Comparisons between subject and training groups did not reveal any interactions. Thus, an isometric training approach was superior in terms of enhancing core stiffness. This is important since increased core stiffness enhances load bearing ability, arrests painful vertebral micromovements, and enhances ballistic distal limb movement. This may explain the efficacy reported for back and knee injury reduction.

Finite element based nonlinear normalization of human lumbar intervertebral disc stiffness to account for its morphology.

Science.gov (United States)

Maquer, Ghislain; Laurent, Marc; Brandejsky, Vaclav; Pretterklieber, Michael L; Zysset, Philippe K

2014-06-01

Disc degeneration, usually associated with low back pain and changes of intervertebral stiffness, represents a major health issue. As the intervertebral disc (IVD) morphology influences its stiffness, the link between mechanical properties and degenerative grade is partially lost without an efficient normalization of the stiffness with respect to the morphology. Moreover, although the behavior of soft tissues is highly nonlinear, only linear normalization protocols have been defined so far for the disc stiffness. Thus, the aim of this work is to propose a nonlinear normalization based on finite elements (FE) simulations and evaluate its impact on the stiffness of human anatomical specimens of lumbar IVD. First, a parameter study involving simulations of biomechanical tests (compression, flexion/extension, bilateral torsion and bending) on 20 FE models of IVDs with various dimensions was carried out to evaluate the effect of the disc's geometry on its compliance and establish stiffness/morphology relations necessary to the nonlinear normalization. The computed stiffness was then normalized by height (H), cross-sectional area (CSA), polar moment of inertia (J) or moments of inertia (Ixx, Iyy) to quantify the effect of both linear and nonlinear normalizations. In the second part of the study, T1-weighted MRI images were acquired to determine H, CSA, J, Ixx and Iyy of 14 human lumbar IVDs. Based on the measured morphology and pre-established relation with stiffness, linear and nonlinear normalization routines were then applied to the compliance of the specimens for each quasi-static biomechanical test. The variability of the stiffness prior to and after normalization was assessed via coefficient of variation (CV). The FE study confirmed that larger and thinner IVDs were stiffer while the normalization strongly attenuated the effect of the disc geometry on its stiffness. Yet, notwithstanding the results of the FE study, the experimental stiffness showed consistently

Rigidez do papelão ondulado: comparação entre resultados experimentais e os obtidos por cálculo analítico Bending stiffness evaluation of cardboard: comparison between experimental and analytically results

Directory of Open Access Journals (Sweden)

Paulo G. Magalhães

2006-04-01

transverse direction. The papers liner and medium resistance to the traction, used to calculate the bending stiffness, was determined in a universal machine test. To obtaining of the bending stiffens the four points test was accomplished. Expressive variations among the methods from which the modulus of elasticity is obtained were observed and that influence the bending stiffness of the structure. The stiffness values obtained experimentally were always greater than the values obtained from analytical method. This difference can be attributed to two factors, the production processes that assurance a larger rigidity than the components separately and the addition of the adhesive layer that is not taken in consideration in the analytic calculations.

Palm to Finger Ulnar Sensory Nerve Conduction.

Science.gov (United States)

Davidowich, Eduardo; Nascimento, Osvaldo J M; Orsini, Marco; Pupe, Camila; Pessoa, Bruno; Bittar, Caroline; Pires, Karina Lebeis; Bruno, Carlos; Coutinho, Bruno Mattos; de Souza, Olivia Gameiro; Ribeiro, Pedro; Velasques, Bruna; Bittencourt, Juliana; Teixeira, Silmar; Bastos, Victor Hugo

2015-12-29

Ulnar neuropathy at the wrist (UNW) is rare, and always challenging to localize. To increase the sensitivity and specificity of the diagnosis of UNW many authors advocate the stimulation of the ulnar nerve (UN) in the segment of the wrist and palm. The focus of this paper is to present a modified and simplified technique of sensory nerve conduction (SNC) of the UN in the wrist and palm segments and demonstrate the validity of this technique in the study of five cases of type III UNW. The SNC of UN was performed antidromically with fifth finger ring recording electrodes. The UN was stimulated 14 cm proximal to the active electrode (the standard way) and 7 cm proximal to the active electrode. The normal data from amplitude and conduction velocity (CV) ratios between the palm to finger and wrist to finger segments were obtained. Normal amplitude ratio was 1.4 to 0.76. Normal CV ratio was 0.8 to 1.23.We found evidences of abnormal SNAP amplitude ratio or substantial slowing of UN sensory fibers across the wrist in 5 of the 5 patients with electrophysiological-definite type III UNW.

Palm to finger ulnar sensory nerve conduction

Directory of Open Access Journals (Sweden)

Eduardo Davidowich

2015-12-01

Full Text Available Ulnar neuropathy at the wrist (UNW is rare, and always challenging to localize. To increase the sensitivity and specificity of the diagnosis of UNW many authors advocate the stimulation of the ulnar nerve (UN in the segment of the wrist and palm. The focus of this paper is to present a modified and simplified technique of sensory nerve conduction (SNC of the UN in the wrist and palm segments and demonstrate the validity of this technique in the study of five cases of type III UNW. The SNC of UN was performed antidromically with fifth finger ring recording electrodes. The UN was stimulated 14 cm proximal to the active electrode (the standard way and 7 cm proximal to the active electrode. The normal data from amplitude and conduction velocity (CV ratios between the palm to finger and wrist to finger segments were obtained. Normal amplitude ratio was 1.4 to 0.76. Normal CV ratio was 0.8 to 1.23.We found evidences of abnormal SNAP amplitude ratio or substantial slowing of UN sensory fibers across the wrist in 5 of the 5 patients with electrophysiological-definite type III UNW.

Paralisia do nervo ulnar na lepra sem alterações cutâneas: biópsia do ramo superficial do nervo ulnar na mão

Directory of Open Access Journals (Sweden)

FREITAS MARCOS R. G. DE

1998-01-01

Full Text Available A lepra constitui causa frequente de acometimento de nervos periféricos, em nosso meio. O sistema nervoso periférico é acometido por vezes sem que haja alterações cutâneas: é a chamada forma neurítica pura. Nessa variante, o nervo mais afetado é o ulnar. Nos casos de acometimento isolado de nervos periféricos somente a feitura de biópsia de nervo conduzirá ao diagnóstico. Assim, resolvemos realizar biópsia do ramo sensitivo superficial do nervo ulnar na mão em 17 pacientes com paresia ou paralisia desse nervo e espessamento do mesmo na altura do cotovelo. Os principais achados foram: redução do número de fibras mielínicas em 14 casos, infiltrado inflamatório em 13, fibrose em 12, desmielinização e remielinização em 9, presença de granuloma em 6 e visualização do Mycobacterium leprae em 5. Concluímos que a biópsia do ramo sensitivo superficial do nervo ulnar na mão é um bom meio diagnóstico de lepra em pacientes com acometimento desse nervo

Dynamic investigation of DNA bending and wrapping by type II topoisomerases

Science.gov (United States)

Shao, Qing; Finzi, Laura; Dunlap, David

2009-11-01

Type II topoisomerases catalyze DNA decatenation and unwinding which is crucial for cell division, and therefore type II topoisomerases are some of the main targets of anti-cancer drugs. A recent crystal structure shows that, during the catalytic cycle, a yeast type II topoimerase can bend a 10 base pair DNA segment by up to 150 degrees. Bacterial gyrase, another type II topoisomerase, can wrap DNA into a tight 180 degree turn. Bending a stiff polymer like DNA requires considerable energy and could represent the rate limiting step in the catalytic (topological) cycle. Using modified deoxyribonucleotides in PCR reactions, stiffer DNA fragments have been produced and used as substrates for topoisomerase II-mediated relaxation of plectonemes introduced in single molecules using magnetic tweezers. The wrapping ability of gyrase decreases for diamino-purine-substituted DNA in which every base pair has three hydrogen-bonds. The overall rate of relaxation of plectonemes by recombinant human topoisomerase II alpha also decreases. These results reveal the dynamic properties of DNA bending and wrapping by type II topisomerases and suggest that A:T base pair melting is a rate determining step for bending and wrapping.

Median and ulnar neuropathies in U.S. Army Medical Command Band members.

Science.gov (United States)

Shaffer, Scott W; Koreerat, Nicholas R; Gordon, Lindsay B; Santillo, Douglas R; Moore, Josef H; Greathouse, David G

2013-12-01

Musicians have been reported as having a high prevalence of upper-extremity musculoskeletal disorders, including carpal tunnel syndrome. The purpose of this study was to determine the presence of median and ulnar neuropathies in U.S. Army Medical Command (MEDCOM) Band members at Fort Sam Houston, Texas. Thirty-five MEDCOM Band members (30 males, 5 females) volunteered to participate. There were 33 right-handed musicians, and the mean length of time in the MEDCOM Band was 12.2 yrs (range, 1-30 yrs). Subjects completed a history form, were interviewed, and underwent a physical examination of the cervical spine and bilateral upper extremities. Nerve conduction studies of the bilateral median and ulnar nerves were performed. Electrophysiological variables served as the reference standard for median and ulnar neuropathy and included distal sensory latencies, distal motor latencies, amplitudes, conduction velocities, and comparison study latencies. Ten of the 35 subjects (29%) presented with abnormal electrophysiologic values suggestive of an upper extremity mononeuropathy. Nine of the subjects had abnormal median nerve electrophysiologic values at or distal to the wrist; 2 had bilateral abnormal values. One had an abnormal ulnar nerve electrophysiologic assessment at the elbow. Nine of these 10 subjects had clinical examination findings consistent with the electrophysiological findings. The prevalence of mononeuropathies in this sample of band members is similar to that found in previous research involving civilian musicians (20-36%) and far exceeds that reported in the general population. Prospective research investigating screening, examination items, and injury prevention measures in musicians appears to be warranted.

Bending Response of Cross-Ply Laminated Composite Plates with Diagonally Perturbed Localized Interfacial Degeneration

Directory of Open Access Journals (Sweden)

Chee Zhou Kam

2013-01-01

Full Text Available A laminated composite plate element with an interface description is developed using the finite element approach to investigate the bending performance of two-layer cross-ply laminated composite plates in presence of a diagonally perturbed localized interfacial degeneration between laminae. The stiffness of the laminate is expressed through the assembly of the stiffnesses of lamina sub-elements and interface element, the latter of which is formulated adopting the well-defined virtually zero-thickness concept. To account for the extent of both shear and axial weak bonding, a degeneration ratio is introduced in the interface formulation. The model has the advantage of simulating a localized weak bonding at arbitrary locations, with various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. Numerical results show that the bending behavior of laminate is significantly affected by the aforementioned parameters, the greatest effect of which is experienced by those with a localized total interface degeneration, representing the case of local delamination.

Contribution to assessing the stiffness reduction of structural elements in the global stability analysis of precast concrete multi-storey buildings

Directory of Open Access Journals (Sweden)

M. C. Marin

Full Text Available This study deals with the reduction of the stiffness in precast concrete structural elements of multi-storey buildings to analyze global stability. Having reviewed the technical literature, this paper present indications of stiffness reduction in different codes, standards, and recommendations and compare these to the values found in the present study. The structural model analyzed in this study was constructed with finite elements using ANSYS® software. Physical Non-Linearity (PNL was considered in relation to the diagrams M x N x 1/r, and Geometric Non-Linearity (GNL was calculated following the Newton-Raphson method. Using a typical precast concrete structure with multiple floors and a semi-rigid beam-to-column connection, expressions for a stiffness reduction coefficient are presented. The main conclusions of the study are as follows: the reduction coefficients obtained from the diagram M x N x 1/r differ from standards that use a simplified consideration of PNL; the stiffness reduction coefficient for columns in the arrangements analyzed were approximately 0.5 to 0.6; and the variation of values found for stiffness reduction coefficient in concrete beams, which were subjected to the effects of creep with linear coefficients from 0 to 3, ranged from 0.45 to 0.2 for positive bending moments and 0.3 to 0.2 for negative bending moments.

Regional variation in the mechanical properties of the vertebral column during lateral bending in Morone saxatilis.

Science.gov (United States)

Nowroozi, B N; Brainerd, E L

2012-10-07

Unlike mammalian, disc-shaped intervertebral joints (IVJs), the IVJs in fishes are biconid structures, filled with fluid and thought to act as hydrostatic hinge joints during swimming. However, it remains unclear which IVJ structures are dominant in mechanical resistance to forces in fishes, and whether variation in these tissues might impact the function of the vertebral column along its length. Here, we measured the dynamic mechanical behaviour of IVJs from striped bass, Morone saxatilis. During lateral bending, angular stiffness was significantly lower in the caudal and cervical regions, relative to the abdominal region. The neutral zone, defined as the range of motion (ROM) at bending moments less than 0.001 Nm, was longer in the caudal relative to the abdominal IVJs. Hysteresis was 30-40% in all regions, suggesting that IVJs may play a role in energy dissipation during swimming. Cutting the vertical septum had no statistically significant effect, but cutting the encapsulating tissues caused a sharp decline in angular stiffness and a substantial increase in ROM and hysteresis. We conclude that stiffness decreases and ROM increases from cranial to caudal in striped bass, and that the encapsulating tissues play a prominent role in mechanical variation along the length of the vertebral column.

The distally-based island ulnar artery perforator flap for wrist defects

Directory of Open Access Journals (Sweden)

Karki Durga

2007-01-01

Full Text Available Background: Reconstruction of soft tissue defects around the wrist with exposed tendons, joints, nerves and bone represents a challenge to plastic surgeons, and such defects necessitate flap coverage to preserve hand functions and to protect its vital structures. We evaluated the use of a distally-based island ulnar artery perforator flap in patients with volar soft tissue defects around the wrist. Materials and Methods: Between June 2004 and June 2006, seven patients of soft tissue defects on the volar aspect of the wrist underwent distally-based island ulnar artery perforator flap. Out of seven patients, five were male and two patients were female. This flap was used in the reconstruction of the post road traffic accident defects in four patients and post electric burn defects in three patients. Flap was raised on one or two perforators and was rotated to 180°. Results: All flaps survived completely. Donor sites were closed primarily without donor site morbidity. Conclusion: The distally-based island Ulnar artery perforator flap is convenient, reliable, easy to manage and is a single-stage technique for reconstructing soft tissue defects of the volar aspect of the wrist. Early use of this flap allows preservation of vital structures, decreases morbidity and allows for early rehabilitation.

Intra-articular Entrapment of Medial Epicondyle Fracture Fragment in Elbow Joint Dislocation Causing Ulnar Neuropraxia: A Case Report

Directory of Open Access Journals (Sweden)

Syed J

2017-03-01

Full Text Available Traumatic elbow dislocations in children are rare but most of them are complex dislocations, and in such dislocations, medial humerus epicondyle fractureis the most common associated injury. Fracture incarceration in the elbow joint occurs in 5-18% of medial humerus epicondyle fractures but ulnar neuropraxia is very rare. Open reduction internal fixation is indicated in medial humerus epicondyle fracture with fracture incarceration, ulnar neuropraxia, marked instability or open fracture. Operative treatment options include fragment excision and sutures, closed or open reduction and Kirschner wire fixation, open reduction and suture fixation, open reduction and smooth pin fixation, and open reduction and screw fixation. However, ulnar nerve transposition is debatable as good outcome had been reported with and without nerve transposition. We report a case of a 13-year old boy, who presented with right elbow dislocation and intra-articular entrapment of medial humerus epicondyle fracture fragment, complicated with sensory ulnar neuropraxia, following a fall onto his right outstretched hand in a motor vehicle accident. The elbow joint was reduced using close manipulative reduction but the fracture fragment remained entrapped post-reduction. The patient then underwent open reduction and screw fixation of the medial humerus epicondyle fracture without ulnar nerve transposition. He had good functional outcome six weeks after surgical intervention, with complete recovery of ulnar neuropraxia six months later. Currently, he is doing well at school and is active with his sporting activity.

Relationship between the Ulnar Nerve and the Branches of the Radial Nerve to the Medial Head of the Triceps Brachii Muscle.

Science.gov (United States)

Sh, Cho; Ih, Chung; Uy, Lee

2018-05-17

One branch of the radial nerve to the medial head of the triceps brachii muscle (MHN) has been described as accompanying or joining the ulnar nerve. Mostly two MHN branches have been reported, with some reports of one; however, the topographical anatomy is not well documented. We dissected 52 upper limbs from adult cadavers and found one, two, and three MHN branches in 9.6%, 80.8%, and 9.6% of cases, respectively. The MHN accompanying the ulnar nerve was always the superior MHN. The relationship between the ulnar nerve and the MHN was classified into four types according to whether the MHN was enveloped along with the ulnar nerve in the connective tissue sheath and whether it was in contact with the ulnar nerve. It contacted the ulnar nerve in 75.0% of cases and accompanied it over a mean distance of 73.6 mm (range 36-116 mm). In all cases in which the connective tissue sheath enveloped the branch of the MHN and the ulnar nerve, removing the sheath confirmed that the MHN branch originated from the radial nerve. The detailed findings and anatomical measurements of the MHN in this study will help in identifying its branches during surgical procedures. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Fitness as a determinant of arterial stiffness in healthy adult men: a cross-sectional study.

Science.gov (United States)

Chung, Jinwook; Kim, Milyang; Jin, Youngsoo; Kim, Yonghwan; Hong, Jeeyoung

2018-01-01

Fitness is known to influence arterial stiffness. This study aimed to assess differences in cardiorespiratory endurance, muscular strength, and flexibility according to arterial stiffness, based on sex and age. We enrolled 1590 healthy adults (men: 1242, women: 348) who were free of metabolic syndrome. We measured cardiorespiratory endurance in an exercise stress test on a treadmill, muscular strength by a grip test, and flexibility by upper body forward-bends from a standing position. The brachial-ankle pulse wave velocity test was performed to measure arterial stiffness before the fitness test. Cluster analysis was performed to divide the patients into groups with low (Cluster 1) and high (Cluster 2) arterial stiffness. According to the k-cluster analysis results, Cluster 1 included 624 men and 180 women, and Cluster 2 included 618 men and 168 women. Men in the middle-aged group with low arterial stiffness demonstrated higher cardiorespiratory endurance, muscular strength, and flexibility than those with high arterial stiffness. Similarly, among men in the old-aged group, the cardiorespiratory endurance and muscular strength, but not flexibility, differed significantly according to arterial stiffness. Women in both clusters showed similar cardiorespiratory endurance, muscular strength, and flexibility regardless of their arterial stiffness. Among healthy adults, arterial stiffness was inversely associated with fitness in men but not in women. Therefore, fitness seems to be a determinant for arterial stiffness in men. Additionally, regular exercise should be recommended for middle-aged men to prevent arterial stiffness.

[Preliminary investigation of treatment of ulnar nerve defect by end-to-side neurorrhaphy].

Science.gov (United States)

Luo, Y; Wang, T; Fang, H

1997-11-01

In the repair of the defect of peripheral nerve, it was necessary to find an operative method with excellent therapeutic effect but simple technique. Based on the experimental study, one case of old injury of the ulnar nerve was treated by end-to-side neurorraphy with the intact median nerve. In this case the nerve defect was over 3 cm and unable to be sutured directly. The patient was followed up for fourteen months after the operation. The recovery of the sensation and the myodynamia was evaluated. The results showed that: the sensation and the motor function innervated by ulnar nerve were recovered. The function of the hand was almost recovered to be normal. It was proved that the end-to-side neurorraphy between the distal stump with the intact median nerve to repair the defect of the ulnar nerve was a new operative procedure for nerve repair. Clinically it had good effect with little operative difficulty. This would give a bright prospect to repair of peripheral nerve defect in the future.

MR neurography of ulnar nerve entrapment at the cubital tunnel: a diffusion tensor imaging study

International Nuclear Information System (INIS)

Breitenseher, Julia B.; Berzaczy, Dominik; Nemec, Stefan F.; Weber, Michael; Prayer, Daniela; Kasprian, Gregor; Kranz, Gottfried; Sycha, Thomas; Hold, Alina

2015-01-01

MR neurography, diffusion tensor imaging (DTI) and tractography at 3 Tesla were evaluated for the assessment of patients with ulnar neuropathy at the elbow (UNE). Axial T2-weighted and single-shot DTI sequences (16 gradient encoding directions) were acquired, covering the cubital tunnel of 46 patients with clinically and electrodiagnostically confirmed UNE and 20 healthy controls. Cross-sectional area (CSA) was measured at the retrocondylar sulcus and FA and ADC values on each section along the ulnar nerve. Three-dimensional nerve tractography and T2-weighted neurography results were independently assessed by two raters. Patients showed a significant reduction of ulnar nerve FA values at the retrocondylar sulcus (p = 0.002) and the deep flexor fascia (p = 0.005). At tractography, a complete or partial discontinuity of the ulnar nerve was found in 26/40 (65 %) of patients. Assessment of T2 neurography was most sensitive in detecting UNE (sensitivity, 91 %; specificity, 79 %), followed by tractography (88 %/69 %). CSA and FA measurements were less effective in detecting UNE. T2-weighted neurography remains the most sensitive MR technique in the imaging evaluation of clinically manifest UNE. DTI-based neurography at 3 Tesla supports the MR imaging assessment of UNE patients by adding quantitative and 3D imaging data. (orig.)

MR neurography of ulnar nerve entrapment at the cubital tunnel: a diffusion tensor imaging study

Energy Technology Data Exchange (ETDEWEB)

Breitenseher, Julia B.; Berzaczy, Dominik; Nemec, Stefan F.; Weber, Michael; Prayer, Daniela; Kasprian, Gregor [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Kranz, Gottfried; Sycha, Thomas [Medical University of Vienna, Department of Neurology, Vienna (Austria); Hold, Alina [Medical University of Vienna, Department of Plastic and Reconstructive Surgery, Vienna (Austria)

2015-07-15

MR neurography, diffusion tensor imaging (DTI) and tractography at 3 Tesla were evaluated for the assessment of patients with ulnar neuropathy at the elbow (UNE). Axial T2-weighted and single-shot DTI sequences (16 gradient encoding directions) were acquired, covering the cubital tunnel of 46 patients with clinically and electrodiagnostically confirmed UNE and 20 healthy controls. Cross-sectional area (CSA) was measured at the retrocondylar sulcus and FA and ADC values on each section along the ulnar nerve. Three-dimensional nerve tractography and T2-weighted neurography results were independently assessed by two raters. Patients showed a significant reduction of ulnar nerve FA values at the retrocondylar sulcus (p = 0.002) and the deep flexor fascia (p = 0.005). At tractography, a complete or partial discontinuity of the ulnar nerve was found in 26/40 (65 %) of patients. Assessment of T2 neurography was most sensitive in detecting UNE (sensitivity, 91 %; specificity, 79 %), followed by tractography (88 %/69 %). CSA and FA measurements were less effective in detecting UNE. T2-weighted neurography remains the most sensitive MR technique in the imaging evaluation of clinically manifest UNE. DTI-based neurography at 3 Tesla supports the MR imaging assessment of UNE patients by adding quantitative and 3D imaging data. (orig.)

Dextran as a fast resorbable and mechanically stiff coating for flexible neural probes

Science.gov (United States)

Kil, D.; Brancato, L.; Puers, R.

2017-11-01

In this paper we report on the use of dextran as a temporary, fast dissolving stiff coating for flexible neural probes. Although polymer-based neural implants offer several advantages, compared to their rigid silicon counterparts, they pose significant challenges during implantation. Due to their extreme flexibility, they have the tendency to buckle under the axial load applied during insertion. The structural stiffness of the implants can be temporarily increased by applying a bioresorbable dextran coating which eases the penetration of neural tissue. For this application three types of dextran with different molecular weights are analysed. The dissolution rate of the coatings is reported as well as the increased bending stiffness resulting from the dextran coating of Parylene C neural probes. Based on these findings the dissolution rate can be linked to parameters such as molecular weight, coating thickness and the surface area exposed to the dissolution medium. The mechanical characterization yields information on how the structural stiffness of neural probes can be tuned by varying the dextran’s molecular weight and coating thickness.

Ulnar neuropathy and medial elbow pain in women's fastpitch softball pitchers: a report of 6 cases.

Science.gov (United States)

Smith, Adam M; Butler, Thomas H; Dolan, Michael S

2017-12-01

Elite-level women's fastpitch softball players place substantial biomechanical strains on the elbow that can result in medial elbow pain and ulnar neuropathic symptoms. There is scant literature reporting the expected outcomes of the treatment of these injuries. This study examined the results of treatment in a series of these patients. We identified 6 female softball pitchers (4 high school and 2 collegiate) with medial elbow pain and ulnar neuropathic symptoms. Trials of conservative care failed in all 6, and they underwent surgical treatment with subcutaneous ulnar nerve transposition. These patients were subsequently monitored postoperatively to determine outcome. All 6 female pitchers had early resolution of elbow pain and neuropathic symptoms after surgical treatment. Long-term follow-up demonstrated that 1 patient quit playing softball because of other injuries but no longer reported elbow pain or paresthesias. One player was able to return to pitching at the high school level but had recurrent forearm pain and neuritis 1 year later while playing a different sport and subsequently stopped playing competitive sports. Four patients continued to play at the collegiate level without further symptoms. Medial elbow pain in women's softball pitchers caused by ulnar neuropathy can be treated effectively with subcutaneous ulnar nerve transposition if nonsurgical options fail. Further study is necessary to examine the role of overuse, proper training techniques, and whether pitching limits may be necessary to avoid these injuries. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Intermuscular aponeuroses between the flexor muscles of the forearm and their relationships with the ulnar nerve.

Science.gov (United States)

Won, Hyung-Sun; Liu, Hong-Fu; Kim, Jun-Ho; Kwak, Dai-Soon; Chung, In-Hyuk; Kim, In-Beom

2016-12-01

The aim of this study was to clarify the morphological characteristics of the intermuscular aponeurosis between the flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS; IMAS), and that between the FCU and flexor digitorum profundus (FDP; IMAP), and their topographic relationships with the ulnar nerve. Fifty limbs of 38 adult cadavers were studied. The IMAS extended along the deep surface of the FCU adjoining the FDS, having the appearance of a ladder, giving off "steps" that decreased in width from superficial to deep around the middle of the forearm. Its proximal part divided into two bands connected by a thin membrane, and was attached to the medial epicondyle and the tubercle (the most medial prominent part of the coronoid process of the ulna), respectively. The IMAP extended deep between the FCU and FDP from the antebrachial fascia, and its distal end was located on the posterior border of the FCU. The IMAP became broader toward its proximal part, and its proximal end was attached anterior and posterior to the tubercle and the olecranon, respectively. The ulnar nerve passed posterior to the medial epicondyle and then medial to the tubercle, and was crossed by the deep border of the IMAS at 58.3 ± 14.1 mm below the medial epicondyle. The deep border of the IMAS and aberrant tendinous structure passing across the ulnar nerve, or the parts of the IMAS and IMAP passing posterior to the ulnar nerve are potential causes of ulnar nerve compression.

Giant-Cell Tumor of the Distal Ulna Treated by Wide Resection and Ulnar Support Reconstruction: A Case Report

Directory of Open Access Journals (Sweden)

Akio Minami

2010-01-01

Full Text Available Giant-cell tumor of bone occurred in the distal end of the ulna is extremely uncommon. A 23-year-old male had a giant-cell tumor occurred in the distal end of the ulna. After wide resection of the distal segment of the ulna including giant-cell tumor, ulnar components of the wrist joint were reconstructed with modified Sauvé-Kapandji procedure using the iliac bone graft, preserving the triangular fibrocartilage complex and ulnar collateral ligament in order to maintain ulnar support of the wrist, and the proximal stump of the resected ulna was stabilized by tenodesis using the extensor carpi ulnaris tendon. One year after operation, the patient's wrist was pain-free and had a full range of motion. Postoperative X-rays showed no abnormal findings including recurrence of the giant-cell tumor and ulnar translation of the entire carpus. The stability of the proximal stump of the distal ulna was also maintained.

Effect of screw position on single cycle to failure in bending and torsion of a locking plate-rod construct in a synthetic feline femoral gap model.

Science.gov (United States)

Niederhäuser, Simone K; Tepic, Slobodan; Weber, Urs T

2015-05-01

To evaluate the effect of screw position on strength and stiffness of a combination locking plate-rod construct in a synthetic feline femoral gap model. 30 synthetic long-bone models derived from beechwood and balsa wood. 3 constructs (2 locking plate-rod constructs and 1 locking plate construct; 10 specimens/construct) were tested in a diaphyseal bridge plating configuration by use of 4-point bending and torsion. Variables included screw position (near the fracture gap and far from the fracture gap) and application of an intramedullary pin. Constructs were tested to failure in each loading mode to determine strength and stiffness. Failure was defined as plastic deformation of the plate or breakage of the bone model or plate. Strength, yield angle, and stiffness were compared by use of a Wilcoxon test. Placement of screws near the fracture gap did not increase bending or torsional stiffness in the locking plate-rod constructs, assuming the plate was placed on the tension side of the bone. Addition of an intramedullary pin resulted in a significant increase in bending strength of the construct. Screw positioning did not have a significant effect on any torsion variables. Results of this study suggested that, in the investigated plate-rod construct, screw insertion adjacent to the fracture lacked mechanical advantages over screw insertion at the plate ends. For surgeons attempting to minimize soft tissue dissection, the decision to make additional incisions for screw placement should be considered with even more caution.

Sleeve bridging of the rhesus monkey ulnar nerve with muscular branches of the pronator teres: multiple amplification of axonal regeneration

Directory of Open Access Journals (Sweden)

Yu-hui Kou

2015-01-01

Full Text Available Multiple-bud regeneration, i.e., multiple amplification, has been shown to exist in peripheral nerve regeneration. Multiple buds grow towards the distal nerve stump during proximal nerve fiber regeneration. Our previous studies have verified the limit and validity of multiple amplification of peripheral nerve regeneration using small gap sleeve bridging of small donor nerves to repair large receptor nerves in rodents. The present study sought to observe multiple amplification of myelinated nerve fiber regeneration in the primate peripheral nerve. Rhesus monkey models of distal ulnar nerve defects were established and repaired using muscular branches of the right forearm pronator teres. Proximal muscular branches of the pronator teres were sutured into the distal ulnar nerve using the small gap sleeve bridging method. At 6 months after suture, two-finger flexion and mild wrist flexion were restored in the ulnar-sided injured limbs of rhesus monkey. Neurophysiological examination showed that motor nerve conduction velocity reached 22.63 ± 6.34 m/s on the affected side of rhesus monkey. Osmium tetroxide staining demonstrated that the number of myelinated nerve fibers was 1,657 ± 652 in the branches of pronator teres of donor, and 2,661 ± 843 in the repaired ulnar nerve. The rate of multiple amplification of regenerating myelinated nerve fibers was 1.61. These data showed that when muscular branches of the pronator teres were used to repair ulnar nerve in primates, effective regeneration was observed in regenerating nerve fibers, and functions of the injured ulnar nerve were restored to a certain extent. Moreover, multiple amplification was subsequently detected in ulnar nerve axons.

Sleeve bridging of the rhesus monkey ulnar nerve with muscular branches of the pronator teres: multiple amplification of axonal regeneration.

Science.gov (United States)

Kou, Yu-Hui; Zhang, Pei-Xun; Wang, Yan-Hua; Chen, Bo; Han, Na; Xue, Feng; Zhang, Hong-Bo; Yin, Xiao-Feng; Jiang, Bao-Guo

2015-01-01

Multiple-bud regeneration, i.e., multiple amplification, has been shown to exist in peripheral nerve regeneration. Multiple buds grow towards the distal nerve stump during proximal nerve fiber regeneration. Our previous studies have verified the limit and validity of multiple amplification of peripheral nerve regeneration using small gap sleeve bridging of small donor nerves to repair large receptor nerves in rodents. The present study sought to observe multiple amplification of myelinated nerve fiber regeneration in the primate peripheral nerve. Rhesus monkey models of distal ulnar nerve defects were established and repaired using muscular branches of the right forearm pronator teres. Proximal muscular branches of the pronator teres were sutured into the distal ulnar nerve using the small gap sleeve bridging method. At 6 months after suture, two-finger flexion and mild wrist flexion were restored in the ulnar-sided injured limbs of rhesus monkey. Neurophysiological examination showed that motor nerve conduction velocity reached 22.63 ± 6.34 m/s on the affected side of rhesus monkey. Osmium tetroxide staining demonstrated that the number of myelinated nerve fibers was 1,657 ± 652 in the branches of pronator teres of donor, and 2,661 ± 843 in the repaired ulnar nerve. The rate of multiple amplification of regenerating myelinated nerve fibers was 1.61. These data showed that when muscular branches of the pronator teres were used to repair ulnar nerve in primates, effective regeneration was observed in regenerating nerve fibers, and functions of the injured ulnar nerve were restored to a certain extent. Moreover, multiple amplification was subsequently detected in ulnar nerve axons.

Reliability, reference values and predictor variables of the ulnar sensory nerve in disease free adults.

Science.gov (United States)

Ruediger, T M; Allison, S C; Moore, J M; Wainner, R S

2014-09-01

The purposes of this descriptive and exploratory study were to examine electrophysiological measures of ulnar sensory nerve function in disease free adults to determine reliability, determine reference values computed with appropriate statistical methods, and examine predictive ability of anthropometric variables. Antidromic sensory nerve conduction studies of the ulnar nerve using surface electrodes were performed on 100 volunteers. Reference values were computed from optimally transformed data. Reliability was computed from 30 subjects. Multiple linear regression models were constructed from four predictor variables. Reliability was greater than 0.85 for all paired measures. Responses were elicited in all subjects; reference values for sensory nerve action potential (SNAP) amplitude from above elbow stimulation are 3.3 μV and decrement across-elbow less than 46%. No single predictor variable accounted for more than 15% of the variance in the response. Electrophysiologic measures of the ulnar sensory nerve are reliable. Absent SNAP responses are inconsistent with disease free individuals. Reference values recommended in this report are based on appropriate transformations of non-normally distributed data. No strong statistical model of prediction could be derived from the limited set of predictor variables. Reliability analyses combined with relatively low level of measurement error suggest that ulnar sensory reference values may be used with confidence. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Sonography of injury of the ulnar collateral ligament of the elbow - initial experience

International Nuclear Information System (INIS)

Miller, Theodore T.; Adler, Ronald S.; Friedman, Lawrence

2004-01-01

The purpose of this study is to describe the sonographic appearance of injuries of the ulnar collateral ligament (UCL) of the elbow. Eight non-professional male baseball pitchers, ages 13-35 years, with medial elbow pain and clinical suspicion of ulnar collateral ligament injury, were referred for imaging. All eight underwent sonography of the affected and contralateral asymptomatic elbow, and six also underwent MR imaging. Neither valgus stress nor power Doppler was used during the sonographic examinations. Time from onset of symptoms to imaging was 1.5 weeks to 6 months. Three patients had surgical confirmation of their injuries, with time from imaging to surgery of 2 days to 9 months. In four patients, the UCL was ruptured, manifest sonographically in three cases as discontinuity of the normally hyperechoic ligament with anechoic fluid in the gap and in one case as non-visualization of the ligament with heterogeneous echogenicity in the expected location of the ligament. Two adolescent patients had avulsions of the UCL from the medial epicondyle, with sonographic demonstration of the avulsed echogenic bony fragment in both cases. One patient had a mild sprain, manifest as mild thickening and decreased echogenicity of the ligament sonographically compared with the contralateral normal elbow, with mild surrounding hypoechoic edema. The eighth patient had a small partial tear of the deep surface of the distal aspect of the ligament, visualized as a hypoechoic focus between the deep surface of the ligament and its ulnar attachment. Tears of the ulnar collateral ligament are manifested sonographically as non-visualization of the ligament or alteration of the normal morphology. (orig.)

Severe Ulnar Nerve Injury After Bee Venom Acupuncture at a Traditional Korean Medicine Clinic: A Case Report.

Science.gov (United States)

Park, Joon Sang; Park, Yoon Ghil; Jang, Chul Hoon; Cho, Yoo Na; Park, Jung Hyun

2017-06-01

This case report describes a severe nerve injury to the right ulnar nerve, caused by bee venom acupuncture. A 52-year-old right-handed man received bee venom acupuncture on the medial side of his right elbow and forearm, at a Traditional Korean Medicine (TKM) clinic. Immediately after acupuncture, the patient experienced pain and swelling on the right elbow. There was further development of weakness of the right little finger, and sensory changes on the ulnar dermatome of the right hand. The patient visited our clinic 7 days after acupuncture. Electrodiagnostic studies 2 weeks after the acupuncture showed ulnar nerve damage. The patient underwent steroid pulse and rehabilitation treatments. However, his condition did not improve completely, even 4 months after acupuncture.

Morphing wing structure with controllable twist based on adaptive bending-twist coupling

Science.gov (United States)

Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo

2013-06-01

A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.

Breathing, bubbling, and bending: DNA flexibility from multimicrosecond simulations

Science.gov (United States)

Zeida, Ari; Machado, Matías Rodrigo; Dans, Pablo Daniel; Pantano, Sergio

2012-08-01

Bending of the seemingly stiff DNA double helix is a fundamental physical process for any living organism. Specialized proteins recognize DNA inducing and stabilizing sharp curvatures of the double helix. However, experimental evidence suggests a high protein-independent flexibility of DNA. On the basis of coarse-grained simulations, we propose that DNA experiences thermally induced kinks associated with the spontaneous formation of internal bubbles. Comparison of the protein-induced DNA curvature calculated from the Protein Data Bank with that sampled by our simulations suggests that thermally induced distortions can account for ˜80% of the DNA curvature present in experimentally solved structures.

Breathing, bubbling, and bending: DNA flexibility from multimicrosecond simulations.

Science.gov (United States)

Zeida, Ari; Machado, Matías Rodrigo; Dans, Pablo Daniel; Pantano, Sergio

2012-08-01

Bending of the seemingly stiff DNA double helix is a fundamental physical process for any living organism. Specialized proteins recognize DNA inducing and stabilizing sharp curvatures of the double helix. However, experimental evidence suggests a high protein-independent flexibility of DNA. On the basis of coarse-grained simulations, we propose that DNA experiences thermally induced kinks associated with the spontaneous formation of internal bubbles. Comparison of the protein-induced DNA curvature calculated from the Protein Data Bank with that sampled by our simulations suggests that thermally induced distortions can account for ~80% of the DNA curvature present in experimentally solved structures.

Handlebar palsy--a compression syndrome of the deep terminal (motor) branch of the ulnar nerve in biking.

Science.gov (United States)

Capitani, Daniel; Beer, Serafin

2002-10-01

We describe 3 patients who developed a severe palsy of the intrinsic ulnar supplied hand muscles after bicycle riding. Clinically and electrophysiologically all showed an isolated lesion of the deep terminal motor branch of the ulnar nerve leaving the hypothenar muscle and the distal sensory branch intact. This type of lesion at the canal of Guyon is quite unusual, caused in the majority of cases by chronic external pressure over the ulnar palm. In earlier reports describing this lesion in bicycle riders, most patients experienced this lesion after a long distance ride. Due to the change of riding position and shape of handlebars (horn handle) in recent years, however, even a single bicycle ride may be sufficient to cause a lesion of this ulnar branch. Especially in downhill riding, a large part of the body weight is supported by the hand on the corner of the handlebar leading to a high load at Guyon's canal. As no sensory fibres are affected, the patients are not aware of the ongoing nerve compression until a severe lesion develops. Individual adaptation of the handlebar and riding position seems to be crucial for prevention of this type of nerve lesion.

An analytical study on the static vertical stiffness of wire rope isolators

Energy Technology Data Exchange (ETDEWEB)

Balaji, P. S.; Rahman, M. E.; Ho, Lau Hieng [Curtin University Sarawak, Miri (Malaysia); Moussa, Leblouba [University of Sharjah, Sharjah (United Arab Emirates)

2016-01-15

The vibrations caused by earthquake ground motions or the operations of heavy machineries can affect the functionality of equipment and cause damages to the hosting structures and surrounding equipment. A Wire rope isolator (WRI), which is a type of passive isolator known to be effective in isolating shocks and vibrations, can be used for vibration isolation of lightweight structures and equipment. The primary advantage of the WRI is that it can provide isolation in all three planes and in any orientation. The load-supporting capability of the WRI is identified from the static stiffness in the loading direction. Static stiffness mainly depends on the geometrical and material properties of the WRI. This study develops an analytical model for the static stiffness in the vertical direction by using Castigliano's second theorem. The model is validated by using the experimental results obtained from a series of monotonic loading tests. The flexural rigidity of the wire ropes required in the model is obtained from the transverse bending test. Then, the analytical model is used to conduct a parametric analysis on the effects of wire rope diameter, width, height, and number of turns (loops) on vertical stiffness. The wire rope diameter influences stiffness more than the other geometric parameters. The developed model can be accurately used for the evaluation and design of WRIs.

Stiffness Matters: Part II - The Effects of Plate Stiffness on Load-Sharing and the Progression of Fusion Following ACDF In Vivo.

Science.gov (United States)

Peterson, Joshua M; Chlebek, Carolyn; Clough, Ashley M; Wells, Alexandra K; Batzinger, Kathleen E; Houston, John M; Kradinova, Katerina; Glennon, Joseph C; DiRisio, Darryl J; Ledet, Eric H

2018-03-19

Real time in vivo measurement of forces in the cervical spine of goats following anterior cervical discectomy and fusion (ACDF). To measure interbody forces in the cervical spine during the time course of fusion following ACDF with plates of different stiffnesses. Following ACDF, the biomechanics of the arthrodesis is largely dictated by the plate. The properties of the plate prescribe the extent of load-sharing through the disc space versus the extent of stress-shielding. Load-sharing promotes interbody bone formation and stress-shielding can inhibit maturation of bone. However, these principles have never been validated in vivo. Measuring in vivo biomechanics of the cervical spine is critical to understanding the complex relationships between implant design, interbody loading, load-sharing, and the progression of fusion. Anterior cervical plates of distinct bending stiffnesses were placed surgically following ACDF in goats. A validated custom force-sensing interbody implant was placed in the disc space to measure load-sharing in the spine. Interbody loads were measured in vivo in real time during the course of fusion for each plate. Interbody forces during flexion/extension were highly dynamic. In animals that received high stiffness plates, maximum forces were in extension whereas in animals that received lower stiffness plates, maximum forces were in flexion. As fusion progressed, interbody load magnitude decreased. The magnitude of interbody forces in the cervical spine is dynamic and correlates to activity and posture of the head and neck. The magnitude and consistency of forces in the interbody space correlates to plate stiffness with more compliant plates resulting in more consistent load-sharing. The magnitude of interbody forces decreases as fusion matures suggesting that smart interbody implants may be used as a diagnostic tool to indicate the progression of interbody fusion. N/A.

High-resolution MRI of the ulnar and radial collateral ligaments of the wrist.

Science.gov (United States)

Nozaki, Taiki; Wu, Wei Der; Kaneko, Yasuhito; Rafijah, Gregory; Yang, Lily; Hitt, Dave; Yoshioka, Hiroshi

2017-12-01

Background Accurate diagnosis of injuries to the collateral ligaments of the wrist is technically challenging on MRI. Purpose To investigate usefulness of high-resolution two-dimensional (2D) and isotropic three-dimensional (3D) magnetic resonance imaging (MRI) for identifying and classifying the morphology of the ulnar and radial collateral ligaments (UCL and RCL) of the wrist. Material and Methods Thirty-seven participants were evaluated using 3T coronal 2D and isotropic 3D images by two radiologists independently. The UCL was classified into four types: 1a, narrow attachment to the tip of the ulnar styloid (Tip); 1b, broad attachment to the Tip; 2a, narrow attachment to the medial base of the ulnar styloid (Base); and 2b, broad attachment to the Base. The RCL was also classified into four types: 1a, separate radioscaphoid and scaphotrapezial ligaments (RS + ST) with narrow scaphoid attachment; 1b, RS + ST with broad scaphoid attachment; 2a, continuous radio-scapho-trapezial ligaments (RST) with narrow scaphoid attachment; and 2b, RST with broad scaphoid attachment. The inter-observer reliability of these classifications was calculated. Results Type 1a was the most common of both collateral ligaments. Of UCL classifications, 31.4% were revised after additional review of multiplanar reconstruction (MPR) images from isotropic data. The inter-observer reliability of UCL classification was substantial (k = 0.62) without MPR, and almost perfect (k = 0.84) with MPR. The inter-observer reliability of RCL classification was almost perfect (k = 0.89). Anatomic delineation between the two sequences was not statistically different. Conclusion The UCL and RCL were each identified on high-resolution 2D and isotropic 3D MRI equally well. MPR allows accurate identification of the UCL attachment to the ulnar styloid.

The effect of distal ulnar implant stem material and length on bone strains.

Science.gov (United States)

Austman, Rebecca L; Beaton, Brendon J B; Quenneville, Cheryl E; King, Graham J W; Gordon, Karen D; Dunning, Cynthia E

2007-01-01

Implant design parameters can greatly affect load transfer from the implant stem to the bone. We have investigated the effect of length or material of distal ulnar implant stems on the surrounding bone strains. Eight cadaveric ulnas were instrumented with 12 strain gauges and secured in a customized jig. Strain data were collected while loads (5-30 N) were applied to the medial surface of the native ulnar head. The native ulnar head was removed, and a stainless steel implant with an 8-cm-long finely threaded stem was cemented into the canal. After the cement had cured, the 8-cm stem was removed, leaving a threaded cement mantle in the canal that could accept shorter threaded stems of interest. The loading protocol was then repeated for stainless steel stems that were 7, 5, and 3 cm in length, as well as for a 5-cm-long titanium alloy (TiAl(6)V(4)) stem. Other stainless steel stem lengths between 3 and 7 cm were tested at intervals of 0.5 cm, with only a 20 N load applied. No stem length tested matched the native strains at all gauge locations. No significant differences were found between any stem length and the native bone at the 5th and 6th strain gauge positions. Strains were consistently closer to the native bone strains with the titanium stem than the stainless steel stem for each gauge pair that was positioned on the bone overlying the stem. The 3-cm stem results were closer to the native strains than the 7-cm stem for all loads at gauges locations that were on top of the stem. The results from this study suggest that the optimal stem characteristics for distal ulnar implants from a load transfer point of view are possessed by shorter (approximately 3 to 4 cm) titanium stems.

KIN SP: A boundary element method based code for single pile kinematic bending in layered soil

Directory of Open Access Journals (Sweden)

Stefano Stacul

2018-02-01

Full Text Available In high seismicity areas, it is important to consider kinematic effects to properly design pile foundations. Kinematic effects are due to the interaction between pile and soil deformations induced by seismic waves. One of the effect is the arise of significant strains in weak soils that induce bending moments on piles. These moments can be significant in presence of a high stiffness contrast in a soil deposit. The single pile kinematic interaction problem is generally solved with beam on dynamic Winkler foundation approaches (BDWF or using continuous models. In this work, a new boundary element method (BEM based computer code (KIN SP is presented where the kinematic analysis is preceded by a free-field response analysis. The analysis results of this method, in terms of bending moments at the pile-head and at the interface of a two-layered soil, are influenced by many factors including the soil–pile interface discretization. A parametric study is presented with the aim to suggest the minimum number of boundary elements to guarantee the accuracy of a BEM solution, for typical pile–soil relative stiffness values as a function of the pile diameter, the location of the interface of a two-layered soil and of the stiffness contrast. KIN SP results have been compared with simplified solutions in literature and with those obtained using a quasi-three-dimensional (3D finite element code.

Perforator anatomy of the radial forearm free flap versus the ulnar forearm free flap for head and neck reconstruction

NARCIS (Netherlands)

Hekner, D.D.; Roeling, TAP; van Cann, EM

The aim of this study was to investigate the vascular anatomy of the distal forearm in order to optimize the choice between the radial forearm free flap and the ulnar forearm free flap and to select the best site to harvest the flap. The radial and ulnar arteries of seven fresh cadavers were

Evaluating the Ergonomic Benefit of a Wrist Brace on Wrist Posture, Muscle Activity, Rotational Stiffness, and Peak Shovel-Ground Impact Force During a Simulated Tree-Planting Task.

Science.gov (United States)

Sheahan, Peter J; Cashaback, Joshua G A; Fischer, Steven L

2017-09-01

Background Tree planters are at a high risk for wrist injury due to awkward postures and high wrist loads experienced during each planting cycle, specifically at shovel-ground impact. Wrist joint stiffness provides a measure that integrates postural and loading information. Objective The purpose of this study was to evaluate wrist joint stiffness requirements at the instant of shovel-ground impact during tree planting and determine if a wrist brace could alter muscular contributions to wrist joint stiffness. Method Planters simulated tree planting with and without wearing a brace on their planting arm. Surface electromyography (sEMG) from six forearm muscles and wrist kinematics were collected and used to calculate muscular contributions to joint rotational stiffness about the wrist. Results Wrist joint stiffness increased with brace use, an unanticipated and negative consequence of wearing a brace. As a potential benefit, planters achieved a more neutrally oriented wrist angle about the flexion/extension axis, although a less neutral wrist angle about the ulnar/radial axis was observed. Muscle activity did not change between conditions. Conclusion The joint stiffness analysis, combining kinematic and sEMG information in a biologically relevant manner, revealed clear limitations with the interface between the brace grip and shovel handle that jeopardized the prophylactic benefits of the current brace design. This limitation was not as evident when considering kinematics and sEMG data independently. Application A neuromechanical model (joint rotational stiffness) enhanced our ability to evaluate the brace design relative to kinematic and sEMG parameter-based metrics alone.

Effect of chain stiffness on the structure of single-chain polymer nanoparticles

Science.gov (United States)

Moreno, Angel J.; Bacova, Petra; Lo Verso, Federica; Arbe, Arantxa; Colmenero, Juan; Pomposo, José A.

2018-01-01

Polymeric single-chain nanoparticles (SCNPs) are soft nano-objects synthesized by purely intramolecular cross-linking of single polymer chains. By means of computer simulations, we investigate the conformational properties of SCNPs as a function of the bending stiffness of their linear polymer precursors. We investigate a broad range of characteristic ratios from the fully flexible case to those typical of bulky synthetic polymers. Increasing stiffness hinders bonding of groups separated by short contour distances and increases looping over longer distances, leading to more compact nanoparticles with a structure of highly interconnected loops. This feature is reflected in a crossover in the scaling behaviour of several structural observables. The scaling exponents change from those characteristic for Gaussian chains or rings in θ-solvents in the fully flexible limit, to values resembling fractal or ‘crumpled’ globular behaviour for very stiff SCNPs. We characterize domains in the SCNPs. These are weakly deformable regions that can be seen as disordered analogues of domains in disordered proteins. Increasing stiffness leads to bigger and less deformable domains. Surprisingly, the scaling behaviour of the domains is in all cases similar to that of Gaussian chains or rings, irrespective of the stiffness and degree of cross-linking. It is the spatial arrangement of the domains which determines the global structure of the SCNP (sparse Gaussian-like object or crumpled globule). Since intramolecular stiffness can be varied through the specific chemistry of the precursor or by introducing bulky side groups in its backbone, our results propose a new strategy to tune the global structure of SCNPs.

A Non-linear Model for Predicting Tip Position of a Pliable Robot Arm Segment Using Bending Sensor Data

Directory of Open Access Journals (Sweden)

Elizabeth I. SKLAR

2016-04-01

Full Text Available Using pliable materials for the construction of robot bodies presents new and interesting challenges for the robotics community. Within the EU project entitled STIFFness controllable Flexible & Learnable manipulator for surgical Operations (STIFF-FLOP, a bendable, segmented robot arm has been developed. The exterior of the arm is composed of a soft material (silicone, encasing an internal structure that contains air-chamber actuators and a variety of sensors for monitoring applied force, position and shape of the arm as it bends. Due to the physical characteristics of the arm, a proper model of robot kinematics and dynamics is difficult to infer from the sensor data. Here we propose a non-linear approach to predicting the robot arm posture, by training a feed-forward neural network with a structured series of pressures values applied to the arm's actuators. The model is developed across a set of seven different experiments. Because the STIFF-FLOP arm is intended for use in surgical procedures, traditional methods for position estimation (based on visual information or electromagnetic tracking will not be possible to implement. Thus the ability to estimate pose based on data from a custom fiber-optic bending sensor and accompanying model is a valuable contribution. Results are presented which demonstrate the utility of our non-linear modelling approach across a range of data collection procedures.

Fretting fatigue behavior of high-strength steel monostrands under bending load

DEFF Research Database (Denmark)

Winkler, Jan; Georgakis, Christos T.; Fischer, Gregor

2015-01-01

In this paper, the fretting fatigue behavior of pretensioned high-strength steel monostrands is investigated. To measure the local deformations on the strands, a novel method based on the digital image correlation (DIC) technique was used to quantify the relative movement between individual wires...... along the length of the monostrand. Information about the monostrand bending stiffness and the extent of relative displacement between core and outer wires of a monostrand undergoing flexural deformations is provided. From the series of dynamic fatigue tests, a fretting fatigue spectrum is derived...

Relationship between Static Stiffness and Modal Stiffness of Structures

Directory of Open Access Journals (Sweden)

Tianjian Ji Tianjian Ji

2010-02-01

Full Text Available This paper derives the relationship between the static stiffness and modal stiffness of a structure. The static stiffness and modal stiffness are two important concepts in both structural statics and dynamics. Although both stiffnesses indicate the capacity of the structure to resist deformation, they are obtained using different methods. The former is calculated by solving the equations of equilibrium and the latter can be obtained by solving an eigenvalue problem. A mathematical relationship between the two stiffnesses was derived based on the definitions of two stiffnesses. This relationship was applicable to a linear system and the derivation of relationships does not reveal any other limitations. Verification of the relationship was given by using several examples. The relationship between the two stiffnesses demonstrated that the modal stiffness of the fundamental mode was always larger than the static stiffness of a structure if the critical point and the maximum mode value are at the same node, i.e. for simply supported beam and seven storeys building are 1.5% and 15% respectively. The relationship could be applied into real structures, where the greater the number of modes being considered, the smaller the difference between the modal stiffness and the static stiffness of a structure.

Reversed Palmaris Longus Muscle Causing Volar Forearm Pain and Ulnar Nerve Paresthesia.

Science.gov (United States)

Bhashyam, Abhiram R; Harper, Carl M; Iorio, Matthew L

2017-04-01

A case of volar forearm pain associated with ulnar nerve paresthesia caused by a reversed palmaris longus muscle is described. The patient, an otherwise healthy 46-year-old male laborer, presented after a previous unsuccessful forearm fasciotomy for complaints of exercise exacerbated pain affecting the volar forearm associated with paresthesia in the ulnar nerve distribution. A second decompressive fasciotomy was performed revealing an anomalous "reversed" palmaris longus, with the muscle belly located distally. Resection of the anomalous muscle was performed with full relief of pain and sensory symptoms. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Ulnar Artery Compression: A Feasible and Effective Approach to Prevent the Radial Artery Occlusion after Coronary Intervention

Directory of Open Access Journals (Sweden)

Jun Tian

2015-01-01

Full Text Available Background: Radial artery (RA occlusion (RAO is not rare in patients undergoing coronary intervention by transradial approach (TRCI. Predictors of and prevention from RAO have not been systematically studied. This study aimed to analyze the risk factors of the weakness of RA pulsation (RAP and its predictive value for RAO after TRCI, and simultaneously to describe a feasible and effective approach to maintain RA patency. Methods: Between June 2006 and March 2010, all patients who underwent TRCI were classified according to the weakness of RAP after removing compression bandage with confirmation by Doppler ultrasound for the first 30 consecutive patients. Among a total of 2658 patients studied, 187 (7% patients having a weaker RAP were prospectively monitored. At 1 h after bandage removal, the ulnar artery in puncture side of all patients was blocked with manual compression to favor brachial and collateral artery blood flow through the RA until a good RAP was restored. The primary analysis was the occurrence of RAO. Results: Doppler ultrasound demonstrated the significant reduction of both systolic velocity (61.24 ± 3.95 cm/s vs. 72.31 ± 3.57 cm/s and diastolic velocity (1.83 ± 0.32 cm/s vs. 17.77 ± 3.97 cm/s in RA at access side as compared to the contralateral RA (all P < 0.001, but these velocities in ipsilateral ulnar artery (81.2 ± 2.16 cm/s and 13.1 ± 2.86 cm/s, respectively increased profoundly. The average time of ulnar artery compression was 4.1 ± 1.2 h (ranged 2.5-6.5 h. There were two patients experienced persistent RAO with a success rate of 98.9% and RAO in 0.075% of patients after ulnar artery compression was applied. The pulsation of the ulnar artery after compression was removed had not been influenced by the compression. Conclusions: After intervention using TRCI approach, the presence of a weaker RAP is an indicator of imminent RAO. The continuing compression of ipsilateral ulnar artery is an effective approach to

Longitudinal relaxation of initially straight flexible and stiff polymers

Science.gov (United States)

Dimitrakopoulos, Panagiotis; Dissanayake, Inuka

2004-11-01

The present talk considers the relaxation of a single flexible or stiff polymer chain from an initial straight configuration in a viscous solvent. This problem commonly arises when strong flows are turned off in both industrial and biological applications. The problem is also motivated by recent experiments with single biopolymer molecules relaxing after being fully extended by applied forces as well as by the recent development of micro-devices involving stretched tethered biopolymers. Our results are applicable to a wide array of synthetic polymers such as polyacrylamides, Kevlar and polyesters as well as biopolymers such as DNA, actin filaments, microtubules and MTV. In this talk we discuss the mechanism of the polymer relaxation as was revealed through Brownian Dynamics simulations covering a broad range of time scales and chain stiffness. After the short-time free diffusion, the chain's longitudinal reduction at early intermediate times is shown to constitute a universal behavior for any chain stiffness caused by a quasi-steady relaxation of tensions associated with the deforming action of the Brownian forces. Stiff chains are shown to exhibit a late intermediate-time longitudinal reduction associated with a relaxation of tensions affected by the deforming Brownian and the restoring bending forces. The longitudinal and transverse relaxations are shown to obey different laws, i.e. the chain relaxation is anisotropic at all times. In the talk, we show how from the knowledge of the relaxation mechanism, we can predict and explain the polymer properties including the polymer stress and the solution birefringence. In addition, a generalized stress-optic law is derived valid for any time and chain stiffness. All polymer properties which depend on the polymer length are shown to exhibit two intermediate-time behaviors with the early one to constitute a universal behavior for any chain stiffness. This work was supported in part by the Minta Martin Research Fund. The

Analysis of the Papal Benediction Sign: The ulnar neuropathy of St. Peter.

Science.gov (United States)

Futterman, Bennett

2015-09-01

The origin of the Papal Benediction Sign has been a source of controversy for many generations of medical students. The question has been whether the Papal Benediction Sign posture is the result of an injury to the median nerve or to the ulnar nerve. The increasingly popular use of online "chat rooms" and the vast quantities of information available on the internet has led to an increasing level of confusion. Looking in major anatomy texts, anatomy and board review books as well as numerous internet sites the answer remains unresolved. Through the analysis of functional anatomy of the hand, cultural and religious practices of the early centuries of the Common Era and church art a clear answer emerges. It will become apparent that this hand posture results from an ulnar neuropathy. Copyright © 2015 Wiley Periodicals, Inc.

Pure neuritic leprosy presenting as ulnar nerve neuropathy: a case report of electrodiagnostic, radiographic, and histopathological findings.

Science.gov (United States)

Payne, Russell; Baccon, Jennifer; Dossett, John; Scollard, David; Byler, Debra; Patel, Akshal; Harbaugh, Kimberly

2015-11-01

Hansen's disease, or leprosy, is a chronic infectious disease with many manifestations. Though still a major health concern and leading cause of peripheral neuropathy in the developing world, it is rare in the United States, with only about 150 cases reported each year. Nevertheless, it is imperative that neurosurgeons consider it in the differential diagnosis of neuropathy. The causative organism is Mycobacterium leprae, which infects and damages Schwann cells in the peripheral nervous system, leading first to sensory and then to motor deficits. A rare presentation of Hansen's disease is pure neuritic leprosy. It is characterized by nerve involvement without the characteristic cutaneous stigmata. The authors of this report describe a case of pure neuritic leprosy presenting as ulnar nerve neuropathy with corresponding radiographic, electrodiagnostic, and histopathological data. This 11-year-old, otherwise healthy male presented with progressive right-hand weakness and numbness with no cutaneous abnormalities. Physical examination and electrodiagnostic testing revealed findings consistent with a severe ulnar neuropathy at the elbow. Magnetic resonance imaging revealed diffuse thickening and enhancement of the ulnar nerve and narrowing at the cubital tunnel. The patient underwent ulnar nerve decompression with biopsy. Pathology revealed acid-fast organisms within the nerve, which was pathognomonic for Hansen's disease. He was started on antibiotic therapy, and on follow-up he had improved strength and sensation in the ulnar nerve distribution. Pure neuritic leprosy, though rare in the United States, should be considered in the differential diagnosis of those presenting with peripheral neuropathy and a history of travel to leprosy-endemic areas. The long incubation period of M. leprae, the ability of leprosy to mimic other conditions, and the low sensitivity of serological tests make clinical, electrodiagnostic, and radiographic evaluation necessary for diagnosis

Association of Gastrocnemius Muscle Stiffness With Passive Ankle Joint Stiffness and Sex-Related Difference in the Joint Stiffness.

Science.gov (United States)

Chino, Kintaro; Takashi, Hideyuki

2017-11-15

Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, we assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggest that muscle stiffness of the MG would not be a prominent factor to determine passive ankle joint stiffness and the sex-related difference in the joint stiffness.

Effect of fascicle composition on ulnar to musculocutaneous nerve transfer (Oberlin transfer) in neonatal brachial plexus palsy.

Science.gov (United States)

Smith, Brandon W; Chulski, Nicholas J; Little, Ann A; Chang, Kate W C; Yang, Lynda J S

2018-06-01

OBJECTIVE Neonatal brachial plexus palsy (NBPP) continues to be a problematic occurrence impacting approximately 1.5 per 1000 live births in the United States, with 10%-40% of these infants experiencing permanent disability. These children lose elbow flexion, and one surgical option for recovering it is the Oberlin transfer. Published data support the use of the ulnar nerve fascicle that innervates the flexor carpi ulnaris as the donor nerve in adults, but no analogous published data exist for infants. This study investigated the association of ulnar nerve fascicle choice with functional elbow flexion outcome in NBPP. METHODS The authors conducted a retrospective study of 13 cases in which infants underwent ulnar to musculocutaneous nerve transfer for NBPP at a single institution. They collected data on patient demographics, clinical characteristics, active range of motion (AROM), and intraoperative neuromonitoring (IONM) (using 4 ulnar nerve index muscles). Standard statistical analysis compared pre- and postoperative motor function improvement between specific fascicle transfer (1-2 muscles for either wrist flexion or hand intrinsics) and nonspecific fascicle transfer (> 2 muscles for wrist flexion and hand intrinsics) groups. RESULTS The patients' average age at initial clinic visit was 2.9 months, and their average age at surgical intervention was 7.4 months. All NBPPs were unilateral; the majority of patients were female (61%), were Caucasian (69%), had right-sided NBPP (61%), and had Narakas grade I or II injuries (54%). IONM recordings for the fascicular dissection revealed a donor fascicle with nonspecific innervation in 6 (46%) infants and specific innervation in the remaining 7 (54%) patients. At 6-month follow-up, the AROM improvement in elbow flexion in adduction was 38° in the specific fascicle transfer group versus 36° in the nonspecific fascicle transfer group, with no statistically significant difference (p = 0.93). CONCLUSIONS Both specific and

Compressive and bending behavior of sandwich panels with Octet truss core fabricated from wires

International Nuclear Information System (INIS)

Lim, Ji Hyun; Nah, Seong Jun; Kang, Ki Ju; Koo, Man Hoe

2005-01-01

Ultra light metal structures have been studied for several years because of their superior specific stiffness, strength and potential of multi functions. Many studies have been focused on how to manufacture ultra light metal structures and optimize them. In this study, we introduced a new idea to make sandwich panels having Octet truss cores. Wires bent in a shape of triangular wave were assembled to construct an Octet truss core and it was bonded with two face sheets to be a sandwich panel. The bending and compressive strength and stiffness were estimated through elementary mechanics for the sandwich specimens with two kinds of face sheets and the results were compared with the ones measured by experiments. Some aspects of assembling and mechanical behavior were discussed compared with Kagome core fabricated from wire, which had been introduced in the authors' previous work

Comparison between open and arthroscopic-assisted foveal triangular fibrocartilage complex repair for post-traumatic distal radio-ulnar joint instability.

Science.gov (United States)

Luchetti, R; Atzei, A; Cozzolino, R; Fairplay, T; Badur, N

2014-10-01

The aim of this study was to assess the objective and subjective functional outcomes after foveal reattachment of proximal or complete ulnar-sided triangular fibrocartilage complex lesions by two surgical procedures: an open technique or an arthroscopically assisted repair. The study was done prospectively on 49 wrists affected by post-traumatic distal radio-ulnar joint instability. Twenty-four patients were treated with the open technique (Group 1) and 25 by the arthroscopically assisted technique (Group 2). Magnetic resonance imaging demonstrated a clear foveal detachment of the triangular fibrocartilage complex in 67% of the cases. Arthroscopy showed a positive ulnar-sided detachment of the triangular fibrocartilage complex (positive hook test) in all cases. Distal radio-ulnar joint stability was obtained in all but five patients at a mean follow-up of 6 months. Both groups had improvement of all parameters with significant differences in wrist pain scores, Mayo wrist score, Disability of the Arm, Shoulder and Hand questionnaire and Patient-Rated Wrist/Hand Evaluation questionnaire scores. There were no significant post-operative differences between the two groups in the outcome parameters except for the Disability of the Arm Shoulder and Hand questionnaire score, which was significantly better in Group 2 (p < 0.001). © The Author(s) 2013.

Dynamic bending of bionic flexible body driven by pneumatic artificial muscles(PAMs) for spinning gait of quadruped robot

Science.gov (United States)

Lei, Jingtao; Yu, Huangying; Wang, Tianmiao

2016-01-01

The body of quadruped robot is generally developed with the rigid structure. The mobility of quadruped robot depends on the mechanical properties of the body mechanism. It is difficult for quadruped robot with rigid structure to achieve better mobility walking or running in the unstructured environment. A kind of bionic flexible body mechanism for quadruped robot is proposed, which is composed of one bionic spine and four pneumatic artificial muscles(PAMs). This kind of body imitates the four-legged creatures' kinematical structure and physical properties, which has the characteristic of changeable stiffness, lightweight, flexible and better bionics. The kinematics of body bending is derived, and the coordinated movement between the flexible body and legs is analyzed. The relationship between the body bending angle and the PAM length is obtained. The dynamics of the body bending is derived by the floating coordinate method and Lagrangian method, and the driving force of PAM is determined. The experiment of body bending is conducted, and the dynamic bending characteristic of bionic flexible body is evaluated. Experimental results show that the bending angle of the bionic flexible body can reach 18°. An innovation body mechanism for quadruped robot is proposed, which has the characteristic of flexibility and achieve bending by changing gas pressure of PAMs. The coordinated movement of the body and legs can achieve spinning gait in order to improve the mobility of quadruped robot.

Ulnar artery: The Ulysses ultimate resort for coronary procedures

Directory of Open Access Journals (Sweden)

George Hahalis, MD, PhD

2016-07-01

Full Text Available Despite the increasing worldwide adoption of the transradial access site, the ulnar artery (UA only very infrequently serves as a primary option for coronary procedures. In contrast to the uncertainty surrounding previous reports regarding the feasibility and safety, recent data from larger registries and randomized trials provide more conclusive evidence that the transulnar route may be safely selected as an alternative arterial access approach. However, a default transulnar strategy appears time-consuming and is associated with higher crossover rates compared with the radial artery (RA. Once arterial access is obtained, the likelihood of a successful coronary procedure is high and similar between the two forearm arteries. The UA has similar flow-mediating vasodilating properties with and seems at least as vulnerable as the RA with regard to incident occlusion, with UA occlusion (UAO rates being probably higher than previously anticipated. A learning curve effect may not be apparent for crossover rates among experienced radialists, but increasing experience is associated with reduction in the fluoroscopy time, contrast volume and frequency of large hematoma formation. The UA may represents an important alternative access site for coronary procedures, and experienced radial operators should obtain additional skills to perform the transulnar approach. Nevertheless, in view of this method's lower feasibility compared to the RA, an initial ulnar access strategy should be reserved for carefully selected patients to ensure satisfactory cannulation rates.

Radiologic examination and measurement of the wrist and distal radio-ulnar joint

International Nuclear Information System (INIS)

Toernvall, A.H.; Ekenstam, F. af; Hagert, C.G.; Irstam, L.; Sahlgrenska Sjukhuset, Goeteborg; Uppsala Univ.

1986-01-01

Following fractures of the distal radius, a relatively high incidence of complications is caused by malalignment in the distal radio-ulnar (DRU) joint; recent anatomic and clinical investigations have shown a congruity of that joint to be of significant importance for restoring the function of the wrist. The radius forms a moderately arched bone, which moves around the ulna in pronation and supination. Biomechanically, the ulna may be regarded as the pillar around which the radius moves. In an anatomic investigation of 5 arm specimens, we have shown that the maximum cartilage contact in the DRU joint between the ulna head and the distal radius occurs in the neutral rotation position. A proposed routine examination method of the wrist and forearm includes a true antero-posterior and a lateral projection of the radius and the ulna, performed with the forearm and wrist in a neutral rotation, a neutral wrist deviation and with the elbow angled 90 degrees. Such an examination implies a standardized and reproducible method. In a radioanatomic investigation, a series of 50 healthy wrists and forearms were examined. A simple measuring technique is presented, applicable to the DRU joint and wrist favouring the ulna as the bone through which a reproducible long axis of the forearm/wrist may be drawn. It is suggested that the length of the radius should be judged relative to the ulna. Ulnar head inclination and radio-ulnar angle are new concepts, being major characteristics of the DRU joint. These angles of the right and left wrist were equal and no difference was found between the sexes. Minor alterations of the distal radius may be revealed when estimating these angles. (orig.)

Multi-stability and variable stiffness of cellular solids designed based on origami patterns

Science.gov (United States)

Sengupta, Sattam; Li, Suyi

2017-04-01

The application of origami-inspired designs to engineered structures and materials has been a subject of much research efforts. These structures and materials, whose mechanical properties are directly related to the geometry of folding, are capable of achieving a host of unique adaptive functions. In this study, we investigate a three-dimensional multistability and variable stiffness function of a cellular solid based on the Miura-Ori folding pattern. The unit cell of such a solid, consisting of two stacked Miura-Ori sheets, can be elastically bistable due to the nonlinear relationship between rigid-folding deformation and crease material bending. Such a bistability possesses an unorthodox property: the critical, unstable configuration lies on the same side of two stable ones, so that two different force-deformation curves co-exist within the same range of deformation. By exploiting such unique stability properties, we can achieve a programmable stiffness change between the two elastically stable states, and the stiffness differences can be prescribed by tailoring the crease patterns of the cell. This paper presents a comprehensive parametric study revealing the correlations between such variable stiffness and various design parameters. The unique properties stemming from the bistability and design of such a unit cell can be advanced further by assembling them into a solid which can be capable of shape morphing and programmable mechanical properties.

Pisotriquetral joint disorders: an under-recognized cause of ulnar side wrist pain

Energy Technology Data Exchange (ETDEWEB)

Moraux, A. [Hopital Roger Salengro, Service d' Imagerie Musculo-Squelettique, Centre de Consultation de l' Appareil Locomoteur, CHRU Lille (France); Imagerie Medicale Jacquemars Gielee, Lille (France); Lefebvre, G.; Pansini, V.; Aucourt, J.; Vandenbussche, L.; Cotten, A. [Hopital Roger Salengro, Service d' Imagerie Musculo-Squelettique, Centre de Consultation de l' Appareil Locomoteur, CHRU Lille (France); Demondion, X. [Hopital Roger Salengro, Service d' Imagerie Musculo-Squelettique, Centre de Consultation de l' Appareil Locomoteur, CHRU Lille (France); Pole Recherche Faculte de Medecine de Lille, Laboratoire d' Anatomie, Lille (France)

2014-06-15

Pisotriquetral joint disorders are often under-recognized in routine clinical practice. They nevertheless represent a significant cause of ulnar side wrist pain. The aim of this article is to present the main disorders of this joint and discuss the different imaging modalities that can be useful for its assessment. (orig.)

Luxation of the elbow complicated by proximal radio-ulnar translocation

International Nuclear Information System (INIS)

Ekloef, O.; Nybonde, T.; Karlsson, G.; St. Goeran's Children's Hospital, Stockholm

1990-01-01

Luxation of the elbow complicated by proximal radio-ulnar translocation is a rare entity. The clue to diagosis is the reversed position of the bones of the proxomal forearm. In the a.p. projection the radial head articulates with the trochlea and the ulna with the capitellum. This unexpected anatomic relationship is easily overlooked. Delayed reduction may result in permanent impairment of elbow motility. Our experience with three recent cases is presented. (orig.)

Luxation of the elbow complicated by proximal radio-ulnar translocation

Energy Technology Data Exchange (ETDEWEB)

Ekloef, O.; Nybonde, T.; Karlsson, G. (St. Goeran' s Children' s Hospital, Stockholm (Sweden). Dept. of Radiology St. Goeran' s Children' s Hospital, Stockholm (Sweden). Dept. of Surgery)

1990-03-01

Luxation of the elbow complicated by proximal radio-ulnar translocation is a rare entity. The clue to diagosis is the reversed position of the bones of the proxomal forearm. In the a.p. projection the radial head articulates with the trochlea and the ulna with the capitellum. This unexpected anatomic relationship is easily overlooked. Delayed reduction may result in permanent impairment of elbow motility. Our experience with three recent cases is presented. (orig.).

Completed Ulnar Shaft Stress Fracture in a Fast-Pitch Softball Pitcher.

Science.gov (United States)

Wiltfong, Roger E; Carruthers, Katherine H; Popp, James E

2017-03-01

Stress fractures of the upper extremity have been previously described in the literature, yet reports of isolated injury to the ulna diaphysis or olecranon are rare. The authors describe a case involving an 18-year-old fast-pitch softball pitcher. She presented with a long history of elbow and forearm pain, which was exacerbated during a long weekend of pitching. Her initial physician diagnosed her as having forearm tendinitis. She was treated with nonsurgical means including rest, anti-inflammatory medications, therapy, and kinesiology taping. She resumed pitching when allowed and subsequently had an acute event immediately ceasing pitching. She presented to an urgent care clinic that evening and was diagnosed as having a complete ulnar shaft fracture subsequently needing surgical management. This case illustrates the need for a high degree of suspicion for ulnar stress fractures in fast-pitch soft-ball pitchers with an insidious onset of unilateral forearm pain. Through early identification and intervention, physicians may be able to reduce the risk of injury progression and possibly eliminate the need for surgical management. [Orthopedics. 2017; 40(2):e360-e362.]. Copyright 2016, SLACK Incorporated.

Coupling between the Output Force and Stiffness in Different Variable Stiffness Actuators

Directory of Open Access Journals (Sweden)

Amir Jafari

2014-08-01

Full Text Available The fundamental objective in developing variable stiffness actuators is to enable the actuator to deliberately tune its stiffness. This is done through controlling the energy flow extracted from internal power units, i.e., the motors of a variable stiffness actuator (VSA. However, the stiffness may also be unintentionally affected by the external environment, over which, there is no control. This paper analysis the correlation between the external loads, applied to different variable stiffness actuators, and their resultant output stiffness. Different types of variable stiffness actuators have been studied considering springs with different types of nonlinearity. The results provide some insights into how to design the actuator mechanism and nonlinearity of the springs in order to increase the decoupling between the load and stiffness in these actuators. This would significantly widen the application range of a variable stiffness actuator.

Ulnar artery: The Ulysses ultimate resort for coronary procedures.

Science.gov (United States)

Hahalis, George; Deftereos, Spyridon; Bertrand, Olivier F

2016-08-20

Despite the increasing worldwide adoption of the transradial access site, the ulnar artery (UA) only very infrequently serves as a primary option for coronary procedures. In contrast to the uncertainty surrounding previous reports regarding the feasibility and safety, recent data from larger registries and randomized trials provide more conclusive evidence that the transulnar route may be safely selected as an alternative arterial access approach. However, a default transulnar strategy appears time-consuming and is associated with higher crossover rates compared with the radial artery (RA). Once arterial access is obtained, the likelihood of a successful coronary procedure is high and similar between the two forearm arteries. The UA has similar flow-mediating vasodilating properties with and seems at least as vulnerable as the RA with regard to incident occlusion, with UA occlusion (UAO) rates being probably higher than previously anticipated. A learning curve effect may not be apparent for crossover rates among experienced radialists, but increasing experience is associated with reduction in the fluoroscopy time, contrast volume and frequency of large hematoma formation. The UA may represents an important alternative access site for coronary procedures, and experienced radial operators should obtain additional skills to perform the transulnar approach. Nevertheless, in view of this method's lower feasibility compared to the RA, an initial ulnar access strategy should be reserved for carefully selected patients to ensure satisfactory cannulation rates. Copyright © 2016 Hellenic Cardiological Society. Published by Elsevier B.V. All rights reserved.

Finite Element Analysis for Bending Process of U-Bending Specimens

Energy Technology Data Exchange (ETDEWEB)

Park, Won Dong; Bahn, Chi Bum [Pusan National University, Busan (Korea, Republic of)

2015-10-15

ASTM G30 suggests that the applied strain can be calculated by dividing thickness by a bend radius. It should be noted, however, that the formula is reliable under an assumption that the ratio of thickness to bend radius is less than 0.2. Typically, to increase the applied stress/strain, the ratio of thickness to bend radius becomes larger than 0.2. This suggests that the estimated strain values by ASTM G30 are not reliable to predict the actual residual strain state of the highly deformed U-bend specimen. For this reason, finite element analysis (FEA) for the bending process of Ubend specimens was conducted by using a commercial finite element analysis software ABAQUS. ver.6.14- 2;2014. From the results of FEA, PWSCC initiation time and U-bend specimen size can be determined exactly. Since local stress and strain have a significant effect on the initiation of PWSCC, it was inappropriate to apply results of ASTM G30 to the PWSCC test directly. According to results of finite element analysis (FEA), elastic relaxation can cause inaccuracy in intended final residual stress. To modify this inaccuracy, additional process reducing the spring back is required. However this additional process also may cause uncertainty of stress/strain state. Therefore, the U-bending specimen size which is not creating uncertainty should be optimized and selected. With the bending radius of 8.3 mm, the thickness of 3 mm and the roller distance of 32.6 mm, calculated maximum stress and strain were 670 MPa and 0.21, respectively.

In-plane and out-of-plane bending tests on carbon steel pipe bends

International Nuclear Information System (INIS)

Brouard, D.; Tremblais, A.; Vrillon, B.

1979-01-01

The objectives of these tests were to obtain experimental results on bends behaviour in elastic and plastic regime by in plane and out of plane bending. Results were used to improve the computer model, for large distorsion of bends, to be used in a simplified beam type computer code for piping calculations. Tests were made on type ANSI B 169 DN 5 bends in ASTM A 106 Grade B carbon steel. These tests made it possible to measure, for identical bends, in elastic regime, the flexibility factors and, in plastic regime, the total evolution in opening, in closing and out of plane. Flexibility factors of 180 0 bend without flanges are approximately the same in opening and in closing. The end effect due to flanges is not very significant, but it is important for 90 0 bends. In plastic regime, collapse loads or collapse moments of bends depends also of both the end effects and the angle bend. The end effects and the angle bend are more sensitive in opening than in closing. The interest of these tests is to procure some precise evolution curves of identical bends well characterized in geometry and metal strength, deflected in large distorsions. (orig./HP)

Sonographic measurements of the ulnar nerve at the elbow with different degrees of elbow flexion.

Science.gov (United States)

Patel, Prutha; Norbury, John W; Fang, Xiangming

2014-05-01

To determine whether there were differences in the cross-sectional area (CSA) and the flattening ratio of the normative ulnar nerve as it passes between the medial epicondyle and the olecranon at 30° of elbow flexion versus 90° of elbow flexion. Bilateral upper extremities of normal healthy adult volunteers were evaluated with ultrasound. The CSA and the flattening ratio of the ulnar nerve at the elbow as it passes between the medial epicondyle and the olecranon were measured, with the elbow flexed at 30° and at 90°, by 2 operators with varying ultrasound scanning experience by using ellipse and direct tracing methods. The results from the 2 different angles of elbow flexion were compared for each individual operator. Finally, intraclass correlations for absolute agreement and consistency between the 2 raters were calculated. An outpatient clinic room at a regional rehabilitation center. Twenty-five normal healthy adult volunteers. The mean CSA and the mean flattening ratio of the ulnar nerve at 30° of elbow flexion and at 90° of elbow flexion. First, for the ellipse method, the mean CSA of the ulnar nerve at 90° (9.93 mm(2)) was slightly larger than at 30° (9.77 mm(2)) for rater 1. However, for rater 2, the mean CSA of the ulnar nerve at 90° (6.80 mm(2)) was slightly smaller than at 30° (7.08 mm(2)). This was found to be statistically insignificant when using a matched pairs t test and the Wilcoxon signed-rank test, with a significance level of .05. Similarly, the difference between the right side and the left side was not statistically significant. The intraclass correlations for absolute agreement between the 2 raters were not very high due to different measurement locations, but the intraclass correlations for consistency were high. Second, for the direct tracing method, the mean CSA at 90° (7.26 mm(2)) was slightly lower than at 30° (7.48 mm(2)). This was found to be statistically nonsignificant when using the matched pairs t test and the

Fortalecimento dos músculos da mão em pacientes submetidos a neurorrafia do ulnar com videogame/Strengthening of hand muscles in patients submitted to neurorrhaphy of ulnar nerve through the videogame

Directory of Open Access Journals (Sweden)

Bruno Goto Kimura

2017-09-01

Full Text Available O objetivo deste trabalho foi verificar se o fortalecimento muscular com o uso do videogame E-link promove aumento da força para os músculos da mão em pacientes com lesão de nervo ulnar. Resultados: Comparando a média das forças de preensão e pinças antes e após o fortalecimento, houve um aumento de força para todos os movimentos. Na força de preensão palmar houve em média um aumento de 50%, na pinça polpa-lateral houve na média um aumento de 24%, na pinça polpa-trípode a média foi de 8% de ganho de força e na pinça polpa-polpa a média foi de 10% de aumento na força. Discussão: A realidade virtual tem sido utilizada atualmente para modificar as terapias tradicionais com o intuito de aumentar a motivação no tratamento, como forma de entretenimento para o paciente, aumentando assim o seu desempenho na realização dos exercícios. Conclusão: Este estudo demonstrou houve ganho de força de preensão e das pinças, após o programa de fortalecimento com o uso do videogame para os músculos intrínsecos e extrínsecos da mão de pacientes após neurorrafia do nervo ulnar. AbstractThe objective of this study was to verify if muscle strengthening using the E-link videogame promotes increased strength for the hand muscles in patients with ulnar nerve injury. Results: Comparing the average grip and pinch strength before and after strengthening, there was an increase in strength for all movements. In the palmar grip strength there was an increase of 50%, in key pinch there was an increase of 24%, in tripod pinch the average was 8% and tip-to-tip pinch the increase was 10% in strength. Discussion: Virtual reality has been use most frequently to modify traditional therapies in order to improve treatment motivation as a form of entertainment for the patient, thus increasing their performance in performing the exercises. Conclusion: This study demonstrated an increase in grip and pinch strength. After the program of strengthening

Ulnar nerve paralysis after forearm bone fracture

Directory of Open Access Journals (Sweden)

Carlos Roberto Schwartsmann

2016-08-01

Full Text Available ABSTRACT Paralysis or nerve injury associated with fractures of forearm bones fracture is rare and is more common in exposed fractures with large soft-tissue injuries. Ulnar nerve paralysis is a rare condition associated with closed fractures of the forearm. In most cases, the cause of paralysis is nerve contusion, which evolves with neuropraxia. However, nerve lacerations and entrapment at the fracture site always need to be borne in mind. This becomes more important when neuropraxia appears or worsens after reduction of a closed fracture of the forearm has been completed. The importance of diagnosing this injury and differentiating its features lies in the fact that, depending on the type of lesion, different types of management will be chosen.

A Study on U-bending Technology using Rotary Draw Bending

Energy Technology Data Exchange (ETDEWEB)

Kwak, Ok-gyu; Kim, Won-seok [BHI Co., Gyunsang-Namdo (Korea, Republic of); Ku, Tae-wan [Pusan National Univ., Busan (Korea, Republic of)

2014-10-15

In the steam generator, heat transfer phenomenon for producing the steam between the primary system of the nuclear reactor and the secondary one occurs around the heat transfer tube. That is, the primary coolant with high temperature(320 .deg.. C) and high pressure(157Kgf/cm2) derived from the reactor flows in the heat transfer tube, and the secondary one runs out that tube. Therefore, it is able to mention that the heat transfer tube itself is a boundary of the heat transfer phenomenon. The heat transfer tube bundle of each steam generator used for the PWR and the PHWR(Pressurized Heavy Water Reactor) is generally composed of about 8,000-13,000 U-tubes. And these tubes are the core component as the structural and heat transfer material in the steam generator, which is in charge of cooling about 70% of the cooling surface of the primary system. For achieving the U-bending process with the thin walled tube, generally, a mandrel could be inserted in the tube according to the bending radius. But when the bending radius is small, the tube U-bending process could be also performed without the mandrel. In this study, numerical and experimental investigations on the U-bending process for producing the heat transfer tubes by using the straight and long tubes were carried out with the consideration of the elastic recovery after the U-bending. In the numerical approach, finite element analysis scheme was adopted with a commercial code, ABAQUS Implicit/Explicit. As the precedent study, the related experiment was also performed to verify the predicted results on the ovality and the minimum wall thickness of the U-bending heat transfer tube. Furthermore, its bending process was also conducted to analyze the deformation behavior for the Alloy 690 tube. In this study, the U-bending process was considered to simulate and manufactured the heat transfer tube used for the steam generator. To investigate the deformation behavior of the U-bending process, and a series of the

Analysis of elastic stiffness for the leaf type holddown spring assembly with uniformly tapered thickness considering the point of taper runout

Energy Technology Data Exchange (ETDEWEB)

Song, Ki Nam [Korea Atomic Energy Research Institute, Daeduk (Korea, Republic of)

1996-04-01

In the case that the point of taper runout is outside the bent region of spring base, a formula to evaluate the elastic stiffness of the leaf type holddown spring (HDS) assembly with uniformly tapered thickness from t{sub 0} to t{sub 1} (t{sub 0}>t{sub 1}) has been analytically derived by applying the engineering beam theory and Casiliano`s theorem based on strain energy. It has found that taper runouts for the 14x14 and 17x17 type KOFA HDS were up to 2.2 mm and effects on their elastic stiffnesses were about 3.70%, and that the elastic stiffness of the HDS was mainly caused by bending moment. And in addition, for the HDS designed/manufactured from Westinghouse, elastic stiffnesses from the derived formula were in good agreement with those from the Westinghouse`s empirical formula. Therefore, the derived formula could be applicable to evaluating the elastic stiffness of any HDS with tapered thickness only with the informations of the geometric data and material properties of leaf springs regardness of the manufacturing companies. 11 tabs., 4 figs., 25 refs. (Author) .new.

Cooling modifies mixed median and ulnar palmar studies in carpal tunnel syndrome Influência do resfriamento nos parâmetros de condução nervosa mista do mediano e ulnar na síndrome do túnel do carpo

Directory of Open Access Journals (Sweden)

Rogério Gayer Machado de Araújo

2007-09-01

Full Text Available Temperature is an important and common variable that modifies nerve conduction study parameters in practice. Here we compare the effect of cooling on the mixed palmar median to ulnar negative peak-latency difference (PMU in electrodiagnosis of carpal tunnel syndrome (CTS. Controls were 22 subjects (19 women, mean age 42.1 years, 44 hands. Patients were diagnosed with mild symptomatic CTS (25 women, mean age 46.6 years, 34 hands. PMU was obtained at the usual temperature, >32°C, and after wrist/hand cooling to Temperatura é uma variável comum e importante que modifica os parâmetros de condução nervosa na prática eletrodiagnóstica. Neste trabalho nós estudamos o efeito do esfriamento na diferença de latências palmares entre o nervo mediano e ulnar (PMU, segmento palma-pulso, utilizada rotineiramente para o eletrodiagnóstico da síndrome do túnel do carpo (STC. Foram estudados 22 controles (19 mulheres, média de idade 42,1 anos, 44 mãos e 25 pacientes (25 mulheres, média de idade 46,6 anos, 34 mãos com diagnóstico de STC leve. PMU foi obtida em temperatura usual (>32°C, e após resfriamento de mão/pulso em água com gelo (<27°C. Após o resfriamento houve aumento significativo na PMU e na latência mista palmar do nervo ulnar nos pacientes quando comparados aos controles. Nós concluímos que o resfriamento modifica significativamente a PMU e propomos que as latências obtidas em nervos submetidos à compressão reagem de maneira mais acentuada ao frio e isso poderia ser uma arma útil para o eletrodiagnóstico da STC incipiente. Da mesma forma, houve reação mais acentuada ao frio no estudo da latência mista palmar do nervo ulnar nos pacientes mas não nos controles, que poderia levantar a hipótese de compressão subclínica do nervo ulnar.

Multi-layered controllable stiffness beams for morphing: energy, actuation force, and material strain considerations

International Nuclear Information System (INIS)

Murray, Gabriel; Gandhi, Farhan

2010-01-01

Morphing aerospace structures could benefit from the ability of structural elements to transition from a stiff load-bearing state to a relatively compliant state that can undergo large deformation at low actuation cost. The present paper focuses on multi-layered beams with controllable flexural stiffness—comprising polymer layers affixed to the surfaces of a base beam and cover layers, in turn, affixed to the surfaces of the polymer layers. Heating the polymer through the glass transition reduces its shear modulus, decouples the cover layers from the base beam and reduces the overall flexural stiffness. Although the stiffness and actuation force required to bend the beam reduce, the energy required to heat the polymer layer must also be considered. Results show that for beams with low slenderness ratios, relatively thick polymer layers, and cover layers whose extensional stiffness is high, the decoupling of the cover layers through softening of the polymer layers can result in flexural stiffness reductions of over 95%. The energy savings are also highest for these configurations, and will increase as the deformation of the beam increases. The decoupling of the cover layers from the base beam through the softening of the polymer reduces the axial strains in the cover layers significantly; otherwise material failure would prevent large deformation. Results show that when the polymer layer is stiff, the cover layers are the dominant contributors to the total energy in the beam, and the energy in the polymer layers is predominantly axial strain energy. When the polymer layers are softened the energy in the cover layers is a small contributor to the total energy which is dominated by energy in the base beam and shear strain energy in the polymer layer

Transfixation pinning and casting of radial-ulnar fractures in calves: A review of three cases.

Science.gov (United States)

St-Jean, G; Debowes, R M

1992-04-01

We reviewed the medical records of three calves with radial-ulnar fractures which were reduced and stabilized by transfixation pinning and casting. Multiple Steinmann pins were placed transversely through proximal and distal fracture fragments and the pin ends were incorporated in fiberglass cast material after fracture reduction. Cast material was placed from proximal to distal radius and served as an external frame to maintain pin position and fracture reduction.At the time of injury, the calves ranged in age from one day to two months and weighed from 37-102 kg. Two fractures were comminuted and one was transverse. All fractures were closed. After surgery, all calves could walk within 24 hours. Radiographic and clinical evidence of fracture healing was present five to seven weeks (mean 6) after surgery. At that time, the pins and cast material were removed. Return to normal function was rapid and judged to be excellent at follow-up evaluation five to nine months later.Advantages of transfixation pinning and casting in management of radial-ulnar fractures include flexibility in pin positioning, adequate maintenance of reduction, early return to weight-bearing status, preservation of joint mobility, and ease of ambulation. The inability to adjust fixation and alignment after cast application is a disadvantage of this technique compared with other external fixators. We concluded that transfixation pinning is a useful means of stabilizing radial-ulnar fractures in pediatric bovine patients.

OroSTIFF: Face-referenced measurement of perioral stiffness in health and disease.

Science.gov (United States)

Chu, Shin-Ying; Barlow, Steven M; Kieweg, Douglas; Lee, Jaehoon

2010-05-28

A new device and automated measurement technology known as OroSTIFF is described to characterize non-participatory perioral stiffness in healthy adults for eventual application to patients with orofacial movement disorders associated with neuromotor disease, traumatic injury, or congenital clefts of the upper lip. Previous studies of perioral biomechanics required head stabilization for extended periods of time during measurement, which precluded sampling patients with involuntary body/head movements (dyskinesias), or pediatric subjects. The OroSTIFF device is face-referenced and avoids the complications associated with head-restraint. Supporting data of non-participatory perioral tissue stiffness using OroSTIFF are included from 10 male and 10 female healthy subjects. The OroSTIFF device incorporates a pneumatic glass air cylinder actuator instrumented for pressure, and an integrated subminiature displacement sensor to encode lip aperture. Perioral electromyograms were simultaneously sampled to confirm passive muscle state for the superior and inferior divisions of the orbicularis oris muscles. Perioral stiffness, derived as a quotient from resultant force (DeltaF) and interangle span (DeltaX), was modeled with multilevel regression techniques. Real-time calculation of the perioral stiffness function demonstrated a significant quadratic relation between imposed interangle stretch and resultant force. This stiffness growth function also differed significantly between males and females. This study demonstrates the OroSTIFF 'proof-of-concept' for cost-effective non-invasive stimulus generation and derivation of perioral stiffness in a group of healthy unrestrained adults, and a case study to illustrate the dose-dependent effects of Levodopa on perioral stiffness in an individual with advanced Parkinson's disease who exhibited marked dyskinesia and rigidity. Copyright 2010 Elsevier Ltd. All rights reserved.

OSTEOID OSTEOMA OF THE HAMATE AS A CAUSE OF COMPRESSION NEUROPATHY OF THE ULNAR NERVE IN GUYON CANAL (CASE REPORT

Directory of Open Access Journals (Sweden)

O. M. Semenkin

2017-01-01

Full Text Available Osteoid  osteoma of the wrist bones is rare and its diagnostics is complicated. A clinical case of the surgical treatment of the patient with osteoid osteoma is presented. The clinical manifestations included  pain, extensors  tenosynovitis and neuropathy of the ulnar nerve in guyon’s canal. The diagnosis was confirmed by computer tomography, ultrasonography and electromyography. Partial resection of the hamate including pathology area, and mobilization of the ulnar nerve in the wrist enabled authors  to obtain a good functional outcome.

Modelling of stiffness and damping change in reinforced concrete structures under seismic actions

International Nuclear Information System (INIS)

Koenig, G.; Oetes, A.

1985-01-01

Restoring force and energy dissipation properties of ductile reinforced concrete structures during seismic excitation are investigated. Interpreting the results of earthquake simulation experiments with large scale reinforced concrete structural members mainly subjected to cyclic bending the various types of the force-deflection response and energy dissipation capability will be identified. Two alternative concepts are suggested for modelling: A rigorous model which considers the numerous deformation and dissipation mechanisms using a step by step algorithm for analysis and a simplified practical model which employs a modified spectrum analysis technique and a simple updating procedure for changing stiffness and damping properties of the members. (orig.)

Adjustable Tooling for Bending Brake

Science.gov (United States)

Ellis, J. M.

1986-01-01

Deep metal boxes and other parts easily fabricated. Adjustable tooling jig for bending brake accommodates spacing blocks and either standard male press-brake die or bar die. Holds spacer blocks, press-brake die, bar window die, or combination of three. Typical bending operations include bending of cut metal sheet into box and bending of metal strip into bracket with multiple inward 90 degree bends. By increasing free space available for bending sheet-metal parts jig makes it easier to fabricate such items as deep metal boxes or brackets with right-angle bends.

A Numerical Study of the Spring-Back Phenomenon in Bending with a Rebar Bending Machine

Directory of Open Access Journals (Sweden)

Chang Hwan Choi

2014-10-01

Full Text Available Recently, the rebar bending methodology started to change from field processing to utilizing rebar bending machines at plant sites prior to transport to the construction locations. Computerized control of rebar plant bending machines provides more accurate and faster bending of rebars than the low quality inefficient field processing alternative. The bending process involves plastic deformation of rebars, where bending stress beyond the yield point of the material is applied. When the bending stress is removed, spring back is caused by the elastic restoring stress. Therefore, an accurate numerical analysis of the spring-back process is required to reduce the bending process errors. The most sensitive factors affecting the spring-back process are the bending radius, the bending angle, the diameter of the rebar, the friction coefficient, and the yielding strength of material. In this paper, we suggest a numerical modeling method using these factors. The finite element modeling of the dynamic mechanical behavior of the material during bending is performed using a commercial dynamic analysis program “DAFUL.” We use the least squares approach to derive the spring-back deflection as a function of the rebar bending parameters.

Effect of relative pile’s stiffness on lateral pile response under loading of large eccentricity

DEFF Research Database (Denmark)

Zania, Varvara; Hededal, Ole; Klinkvort, R.T.

2015-01-01

The wide application of monopiles as foundations for offshore wind turbines has raised the issue of the suitability of the p –y curves proposed by API for lateral pile loading, since the latter were developed after full-scale tests on flexible and slender piles. This study investigates the role...... of the relative pile’s stiffness, when it is subjected to lateral load of large eccentricity. Employing centrifuge experiments, a hollow steel pile well instrumented with strain gauge pairs has been subjected to lateral load. The bending moment distribution of the model pile embedded in uniform, dense, dry sand...... was obtained under two different stress levels and two different embedment depths. Hence, the p – y curves were obtained providing an insight into the effect of the relative pile’s stiffness on the soil – pile interaction, while the effect of the installation process could also be evaluated....

Clarification of Eponymous Anatomical Terminology: Structures Named After Dr Geoffrey V. Osborne That Compress the Ulnar Nerve at the Elbow.

Science.gov (United States)

Wali, Arvin R; Gabel, Brandon; Mitwalli, Madhawi; Tubbs, R Shane; Brown, Justin M

2017-05-01

In 1957, Dr Geoffrey Osborne described a structure between the medial epicondyle and the olecranon that placed excessive pressure on the ulnar nerve. Three terms associated with such structures have emerged: Osborne's band, Osborne's ligament, and Osborne's fascia. As anatomical language moves away from eponymous terminology for descriptive, consistent nomenclature, we find discrepancies in the use of anatomic terms. This review clarifies the definitions of the above 3 terms. We conducted an extensive electronic search via PubMed and Google Scholar to identify key anatomical and surgical texts that describe ulnar nerve compression at the elbow. We searched the following terms separately and in combination: "Osborne's band," "Osborne's ligament," and "Osborne's fascia." A total of 36 papers were included from 1957 to 2016. Osborne's band, Osborne's ligament, and Osborne's fascia were found to inconsistently describe the etiology of ulnar neuritis, referring either to the connective tissue between the 2 heads of the flexor carpi ulnaris muscle as described by Dr Osborne or to the anatomically distinct fibrous tissue between the olecranon process of the ulna and the medial epicondyle of the humerus. The use of eponymous terms to describe ulnar pathology of the elbow remains common, and although these terms allude to the rich history of surgical anatomy, these nonspecific descriptions lead to inconsistencies. As Osborne's band, Osborne's ligament, and Osborne's fascia are not used consistently across the literature, this research demonstrates the need for improved terminology to provide reliable interpretation of these terms among surgeons.

POSSIBLE ENTRAPMENT OF THE ULNAR ARTERY BY THE THIRD HEAD OF PRONATOR TERES MUSCLE. EL POSIBLE ATRAPAMIENTO DE LA ARTERIA ULNAR POR EL TERCER FASCÍCULO DEL MÚSCULO PRONADOR TERES

Directory of Open Access Journals (Sweden)

Satheesha Nayak B

2012-11-01

Full Text Available Knowledge of variations at and in the surroundings of cubital fossa is useful for the orthopedic surgeons, plastic surgeons and medical practitioners in general. During routine dissection, we observed arterial and muscular variations in and around the cubital fossa. The brachial artery terminated 2 inches above the base of the cubital fossa. The radial and ulnar arteries entered the cubital fossa by passing in front of the tendons of brachialis and biceps brachii respectively. The ulnar artery was surrounded by the third head of pronator teres which took its origin from the fascia covering the distal part of the brachialis muscle. This muscle joined pronator teres tendon distally and was supplied by a branch of median nerve. This muscle could alter the blood flow in the ulnar artery and may cause difficulties in recording the blood pressure.El conocimiento de las variaciones en los alrededores de la fosa cubital es útil para cirujanos ortopédicos, cirujanos plásticos y médicos en general. Observamos las variaciones arteriales y musculares en y alrededor de la fosa cubital. La arteria braquial terminó 2 pulgadas por encima de la base de la fosa cubital. Las arterias radiales y cubitales entraron en la fosa cubital pasando delante de los tendones de los músculos braquial y bíceps braquial respectivamente. La arteria cubital estaba rodeada por el tercer fascículo del pronador teres, que tuvo su origen en la fascia cubriendo la parte distal del músculo braquial. Este músculo se unió a tendón de pronador teres distalmente y fue suministrado por una rama del nervio mediano. Este músculo podría alterar el flujo sanguíneo en la arteria cubital y puede causar dificultades para el registro de la presión sanguínea.

Elastic metamaterial beam with remotely tunable stiffness

Energy Technology Data Exchange (ETDEWEB)

Qian, Wei [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Yu, Zhengyue [School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Xiaole [School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Lai, Yun [College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Yellen, Benjamin B., E-mail: yellen@duke.edu [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mechanical Engineering and Materials Science, Duke University, P.O. Box 90300, Hudson Hall, Durham, North Carolina 27708 (United States)

2016-02-07

We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ∼30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

Elastic metamaterial beam with remotely tunable stiffness

Science.gov (United States)

Qian, Wei; Yu, Zhengyue; Wang, Xiaole; Lai, Yun; Yellen, Benjamin B.

2016-02-01

We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ˜30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

A cold mass support system based on the use of oriented fiberglass epoxy rods in bending

International Nuclear Information System (INIS)

Green, Michael A.; Corradi, Carol A.; LaMantia, Roberto F.; Zbasnik, Jon P.

2002-01-01

This report describes a cold mass support system that uses oriented fiberglass epoxy (other low heat leak oriented fiber material can also be used) rods. In the direction of the rods, where forces are carried in tension or compression, the support system is very stiff. In the other directions, the rods are subjected to bending stresses. When the support rods are put in bending the cold mass support is quite compliant. This type of support system can be used in situation where space for a cold mass support system is limited and where compliance can be tolerated in at least one direction. Break test data for 15.9-mm and 19.1-mm diameter oriented fiberglass rods is presented in this report. The cold mass supports for the DFBX distribution boxes are presented as an example of this type of cold mass support system

ULNAR NEURITIS ASSOCIATED WITH GUN STOCK DEFORMITY FOLLOWING SUPRACONDYLAR FRACTURE OF HUMERUS

Directory of Open Access Journals (Sweden)

Sunita Morhan

2014-04-01

Full Text Available Background: This case report describes a patient who was referred to physiotherapist from a hand surgeon. Among the fractures around the elbow joint, radial head fracture and fracture of distal end of radius are common among adults. The occurrence of Supracondylar fractures are more commonly seen in children when compared to adults. One of the complications of this fracture is malunion resulting in Gun stock deformity. The main Purpose of this case report is to explore, 1. The complication associated with gunstock deformity 2. Chances of iatrogenic nerve injury after manipulation under anesthesia. 3.Long term supervised rehabilitation approach. Case Description: A 40 years old male patient referred to our Physiotherapy department by a hand surgeon. After the initial evaluation, findings revealed limitation in right elbow movement and tingling and numbness sensation in little and half of ring fingers in his right side. This patient underwent ulnar nerve transposition surgery followed by rehabilitation. His physiotherapy session includes electrotherapeutic agents for pain relief, passive mobilization of elbow and strengthening program for his flexors and extensors of elbow for a period of one year. Outcome: The outcome of the long term rehabilitation approach for a patient with ulnar neuropathy secondary to gunstock deformity after ulnar nerve transposition surgery is good. The patients tingling and numbness decreased and the range of elbow movement improved significantly. Discussion: Most common complications of fracture of distal end of humerus include malunion,ischemic contracture and nerve injuries. The relative incidence of iatrogenic nerve injuries associatedwith this fracture has been reported as being 2%-6%. Nerve injuries after Supracondylar humeral fractures occur primarily due to tenting or entrapment of the nerve on the sharp proximal humeral fragment, while iatrogenic injuries occur either during closed manipulation or percutaneous

Analytic description of the frictionally engaged in-plane bending process incremental swivel bending (ISB)

Science.gov (United States)

Frohn, Peter; Engel, Bernd; Groth, Sebastian

2018-05-01

Kinematic forming processes shape geometries by the process parameters to achieve a more universal process utilizations regarding geometric configurations. The kinematic forming process Incremental Swivel Bending (ISB) bends sheet metal strips or profiles in plane. The sequence for bending an arc increment is composed of the steps clamping, bending, force release and feed. The bending moment is frictionally engaged by two clamping units in a laterally adjustable bending pivot. A minimum clamping force hindering the material from slipping through the clamping units is a crucial criterion to achieve a well-defined incremental arc. Therefore, an analytic description of a singular bent increment is developed in this paper. The bending moment is calculated by the uniaxial stress distribution over the profiles' width depending on the bending pivot's position. By a Coulomb' based friction model, necessary clamping force is described in dependence of friction, offset, dimensions of the clamping tools and strip thickness as well as material parameters. Boundaries for the uniaxial stress calculation are given in dependence of friction, tools' dimensions and strip thickness. The results indicate that changing the bending pivot to an eccentric position significantly affects the process' bending moment and, hence, clamping force, which is given in dependence of yield stress and hardening exponent. FE simulations validate the model with satisfactory accordance.

Radiologic examination and measurement of the wrist and distal radio-ulnar joint. New aspects

Energy Technology Data Exchange (ETDEWEB)

Toernvall, A.H.; Ekenstam, F. af; Hagert, C.G.; Irstam, L.

Following fractures of the distal radius, a relatively high incidence of complications is caused by malalignment in the distal radio-ulnar (DRU) joint; recent anatomic and clinical investigations have shown a congruity of that joint to be of significant importance for restoring the function of the wrist. The radius forms a moderately arched bone, which moves around the ulna in pronation and supination. Biomechanically, the ulna may be regarded as the pillar around which the radius moves. In an anatomic investigation of 5 arm specimens, we have shown that the maximum cartilage contact in the DRU joint between the ulna head and the distal radius occurs in the neutral rotation position. A proposed routine examination method of the wrist and forearm includes a true antero-posterior and a lateral projection of the radius and the ulna, performed with the forearm and wrist in a neutral rotation, a neutral wrist deviation and with the elbow angled 90 degrees. Such an examination implies a standardized and reproducible method. In a radioanatomic investigation, a series of 50 healthy wrists and forearms were examined. A simple measuring technique is presented, applicable to the DRU joint and wrist favouring the ulna as the bone through which a reproducible long axis of the forearm/wrist may be drawn. It is suggested that the length of the radius should be judged relative to the ulna. Ulnar head inclination and radio-ulnar angle are new concepts, being major characteristics of the DRU joint. These angles of the right and left wrist were equal and no difference was found between the sexes. Minor alterations of the distal radius may be revealed when estimating these angles.

Closed-form plastic collapse loads of pipe bends under combined pressure and in-plane bending

International Nuclear Information System (INIS)

Oh, Chang Sik; Kim, Yun Jae

2006-01-01

Based on three-dimensional (3-D) FE limit analyses, this paper provides plastic limit, collapse and instability load solutions for pipe bends under combined pressure and in-plane bending. The plastic limit loads are determined from FE limit analyses based on elastic-perfectly plastic materials using the small geometry change option, and the FE limit analyses using the large geometry change option provide plastic collapse loads (using the twice-elastic-slope method) and instability loads. For the bending mode, both closing bending and opening bending are considered, and a wide range of parameters related to the bend geometry is considered. Based on the FE results, closed-form approximations of plastic limit and collapse load solutions for pipe bends under combined pressure and bending are proposed

POSSIBLE ENTRAPMENT OF THE ULNAR ARTERY BY THE THIRD HEAD OF PRONATOR TERES MUSCLE. El posible atrapamiento de la arteria ulnar por el tercer fascículo del músculo pronador teres

Directory of Open Access Journals (Sweden)

Naveen Kumar

2016-03-01

Full Text Available El conocimiento de las variaciones en los alrededores de la fosa cubital es útil para cirujanos ortopédicos, cirujanos plásticos y médicos en general. Observamos las variaciones arteriales y musculares en y alrededor de la fosa cubital. La arteria braquial terminó 2 pulgadas por encima de la base de la fosa cubital. Las arterias radiales y cubitales entraron en la fosa cubital  pasando delante de los tendones de los músculos braquial y bíceps braquial respectivamente. La arteria cubital estaba rodeada por el tercer fascículo del pronador teres, que tuvo su origen en la fascia cubriendo la parte distal del músculo braquial. Este músculo se unió a tendón de pronador teres distalmente y fue suministrado por una rama del nervio mediano. Este músculo podría alterar el flujo sanguíneo en la arteria cubital y puede causar dificultades para el registro de la presión sanguínea. Knowledge of variations at and in the surroundings of cubital fossa is useful for the orthopedic surgeons, plastic surgeons and medical practitioners in general. During routine dissection, we observed arterial and muscular variations in and around the cubital fossa. The brachial artery terminated 2 inches above the base of the cubital fossa. The radial and ulnar arteries entered the cubital fossa by passing in front of the tendons of brachialis and biceps brachii respectively. The ulnar artery was surrounded by the third head of pronator teres which took its origin from the fascia covering the distal part of the brachialis muscle. This muscle joined pronator teres tendon distally and was supplied by a branch of median nerve. This muscle could alter the blood flow in the ulnar artery and may cause difficulties in recording the blood pressure.

Elasticity Theory Solution of the Problem on Plane Bending of a Narrow Layered Cantilever Beam by Loads at Its Free End

Science.gov (United States)

Goryk, A. V.; Koval'chuk, S. B.

2018-05-01

An exact elasticity theory solution for the problem on plane bending of a narrow layered composite cantilever beam by tangential and normal loads distributed on its free end is presented. Components of the stress-strain state are found for the whole layers package by directly integrating differential equations of the plane elasticity theory problem by using an analytic representation of piecewise constant functions of the mechanical characteristics of layer materials. The continuous solution obtained is realized for a four-layer beam with account of kinematic boundary conditions simulating the rigid fixation of its one end. The solution obtained allows one to predict the strength and stiffness of composite cantilever beams and to construct applied analytical solutions for various problems on the elastic bending of layered beams.

Plastic loads of pipe bends under combined pressure and out-of-plane bending

International Nuclear Information System (INIS)

Lee, Kuk Hee; Kim, Yun Jae; Park, Chi Yong; Lee, Sung Ho; Kim, Tae Ryong

2007-01-01

Based on three-Dimensional (3-D) FE limit analyses, this paper provides plastic limit and TES(Twice- Elastic-Slope) loads for pipe bends under combined pressure and out-of-plane bending. The plastic limit loads are determined from FE limit analyses based on elastic.perfectly-plastic materials using the small geometry change option, and the FE limit analyses using the large geometry change option provide TES plastic loads. A wide range of parameters related to the bend geometry is considered. Based on the FE results, closed-form approximations of plastic limit and TES plastic load solutions for pipe bends under out-of-plane bending are proposed

Competition between Bending and Internal Pressure Governs the Mechanics of Fluid Nanovesicles.

Science.gov (United States)

Vorselen, Daan; MacKintosh, Fred C; Roos, Wouter H; Wuite, Gijs J L

2017-03-28

Nanovesicles (∼100 nm) are ubiquitous in cell biology and an important vector for drug delivery. Mechanical properties of vesicles are known to influence cellular uptake, but the mechanism by which deformation dynamics affect internalization is poorly understood. This is partly due to the fact that experimental studies of the mechanics of such vesicles remain challenging, particularly at the nanometer scale where appropriate theoretical models have also been lacking. Here, we probe the mechanical properties of nanoscale liposomes using atomic force microscopy (AFM) indentation. The mechanical response of the nanovesicles shows initial linear behavior and subsequent flattening corresponding to inward tether formation. We derive a quantitative model, including the competing effects of internal pressure and membrane bending, that corresponds well to these experimental observations. Our results are consistent with a bending modulus of the lipid bilayer of ∼14k b T. Surprisingly, we find that vesicle stiffness is pressure dominated for adherent vesicles under physiological conditions. Our experimental method and quantitative theory represents a robust approach to study the mechanics of nanoscale vesicles, which are abundant in biology, as well as being of interest for the rational design of liposomal vectors for drug delivery.

Estimates of plastic loads for pipe bends under combined in-plane and out-of-plane bending moment

International Nuclear Information System (INIS)

Kim, Nak Hyun; Oh, Chang Sik; Kim, Yun Jae

2008-01-01

This paper provides a method to estimate plastic loads (defined by twice-elastic-slope) for pipe bends under combined in-plane and out-of-plane bending moment, based on detailed 3-D FE limit analyses using elastic-perfectly plastic materials. Because closing bending moment is always lower than opening bending moment, the combination of in-plane closing bending and out-of-plane bending moment becomes the most significant case. Due to conservatism of each bending moments, the resultant moment provided by ASME B and PV code is unduly conservative. However, the concept of the resultant moment is still valid. In this paper, FE results show that the accurate solutions of bending moments provide better estimates of plastic loads of pipe bend under combined in-plane bending and out-of-plane bending moment

Lamb wave characterization of the effects of long-term thermal-mechanical aging on composite stiffness

Science.gov (United States)

Seale, M. D.; Madaras, E. I.

1999-01-01

Lamb waves offer a promising method of evaluating damage in composite materials. The Lamb wave velocity is directly related to the material parameters, so an effective tool exists to monitor damage in composites by measuring the velocity of these waves. The Lamb Wave Imager (LWI) uses a pulse/receive technique that excites an antisymmetric Lamb mode and measures the time-of-flight over a wide frequency range. Given the material density and plate thickness, the bending and out-of-plane shear stiffnesses are calculated from a reconstruction of the dispersion curve. In this study, the time-of-flight as well as the elastic stiffnesses D11, D22, A44, and A55 for composite samples which have undergone combined thermal and mechanical aging are obtained. The samples examined include a baseline specimen with 0 cycles, specimens which have been aged 2350 and 3530 cycles at high strain levels, and one specimen aged 3530 cycles at low strain levels.

Rupture of the ulnar collateral ligament of the thumb ? a review

OpenAIRE

Mahajan, Mandhkani; Rhemrev, Steven J

2013-01-01

Skier?s thumb is a partial or complete rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. It is an often-encountered injury and can lead to chronic pain and instability when diagnosed incorrectly. Knowledge of the anatomy and accurate physical examination are essential in the evaluation of a patient with skier?s thumb. This article provides a review of the relevant anatomy, the correct method of physical examination and the options for additional imaging a...

Surface orientation effects on bending properties of surgical mesh are independent of tensile properties.

Science.gov (United States)

Simon, David D; Andrews, Sharon M; Robinson-Zeigler, Rebecca; Valdes, Thelma; Woods, Terry O

2018-02-01

Current mechanical testing of surgical mesh focuses primarily on tensile properties even though implanted devices are not subjected to pure tensile loads. Our objective was to determine the flexural (bending) properties of surgical mesh and determine if they correlate with mesh tensile properties. The flexural rigidity values of 11 different surgical mesh designs were determined along three textile directions (machine, cross-machine, and 45° to machine; n = 5 for each) using ASTM D1388-14 while tracking surface orientation. Tensile testing was also performed on the same specimens using ASTM D882-12. Linear regressions were performed to compare mesh flexural rigidity to mesh thickness, areal mass density, filament diameter, ultimate tensile strength, and maximum extension. Of 33 mesh specimen groups, 30 had significant differences in flexural rigidity values when comparing surface orientations (top and bottom). Flexural rigidity and mesh tensile properties also varied with textile direction (machine and cross-machine). There was no strong correlation between the flexural and tensile properties, with mesh thickness having the best overall correlation with flexural rigidity. Currently, surface orientation is not indicated on marketed surgical mesh, and a single mesh may behave differently depending on the direction of loading. The lack of correlation between flexural stiffness and tensile properties indicates the need to examine mesh bending stiffness to provide a more comprehensive understanding of surgical mesh mechanical behaviors. Further investigation is needed to determine if these flexural properties result in the surgical mesh behaving mechanically different depending on implantation direction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 854-862, 2018. © 2017 Wiley Periodicals, Inc.

Treatment of humeroulnar subluxation with a dynamic proximal ulnar osteotomy: a review of 13 cases

International Nuclear Information System (INIS)

Gilson, S.D.; Piermattei, D.L.; Schwarz, P.D.

1989-01-01

Humeroulnar subluxation was treated surgically in 13 dogs with 18 affected elbows using a proximal osteotomy of the ulna that allowed the ulna to elongate dynamically. Distal humeroulnar subluxation was secondary to premature closure of the distal ulnar physis in 16 elbows. One distal subluxation was secondary to a radioulnar synostosis, and one proximal subluxation developed after premature closure of the distal radial physis. The mean follow-up time was 22 months. Twenty-eight percent of the elbows were judged to have excellent results, 22% good results, 50% fair results, and none was judged to have a poor outcome. The presenting lameness grade and the severity of preoperative and postoperative humeroulnar subluxation had significant correlations with the prognosis. Associated orthopedic abnormalities and complications of concurrent surgical procedures affected the outcome in several dogs. Overall, the dynamic proximal ulnar osteotomy was a simple and effective technique for the treatment of uncomplicated humeroulnar subluxation

Influence of Hamstring Tightness in Pelvic, Lumbar and Trunk Range of Motion in Low Back Pain and Asymptomatic Volunteers during Forward Bending

OpenAIRE

Jandre Reis, Felipe Jose; Macedo, Adriana Ribeiro

2015-01-01

Study Design Cross-sectional study. Purpose To verify the association of hamstring tightness and range of motion in anterior pelvic tilt (PT), lumbar motion (LM), and trunk flexion (TF) during forward bending. Overview of Literature Increased hamstring stiffness could be a possible contributing factor to low back injuries. Clinical observations have suggested that hamstring tightness influences lumbar pelvic rhythm. Movement restrictions or postural asymmetry likely lead to compensatory movem...

Limit cycles and stiffness control with variable stiffness actuators

NARCIS (Netherlands)

Carloni, Raffaella; Marconi, L.

2012-01-01

Variable stiffness actuators realize highly dynamic systems, whose inherent mechanical compliance can be properly exploited to obtain a robust and energy-efficient behavior. The paper presents a control strategy for variable stiffness actuators with the primarily goal of tracking a limit cycle

Analysis of the strength and stiffness of timber beams reinforced with carbon fiber and glass fiber

Directory of Open Access Journals (Sweden)

Juliano Fiorelli

2003-06-01

Full Text Available An experimental analysis of pinewood beams (Pinus caribea var hondurensis reinforced with glass and/or carbon fibers is discussed. The theoretical model employed to calculate the beam's bending strength takes into account the timber's ultimate limit states of tensile strength and failure by compression, considering a model of fragile elastic tension and plastic elastic compression. The validity of the theoretical model is confirmed by a comparison of the theoretical and experimental results, while the efficiency of the fiber reinforcement is corroborated by the increased strength and stiffness of the reinforced timber beams.

Recent developments in bend-insensitive and ultra-bend-insensitive fibers

Science.gov (United States)

Boivin, David; de Montmorillon, Louis-Anne; Provost, Lionel; Montaigne, Nelly; Gooijer, Frans; Aldea, Eugen; Jensma, Jaap; Sillard, Pierre

2010-02-01

Designed to overcome the limitations in case of extreme bending conditions, Bend- and Ultra-Bend-Insensitive Fibers (BIFs and UBIFs) appear as ideal solutions for use in FTTH networks and in components, pigtails or patch-cords for ever demanding applications such as military or sensing. Recently, however, questions have been raised concerning the Multi-Path-Interference (MPI) levels in these fibers. Indeed, they are potentially subject to interferences between the fundamental mode and the higher-order mode that is also bend resistant. This MPI is generated because of discrete discontinuities such as staples, bends and splices/connections that occur on distance scales that become comparable to the laser coherent length. In this paper, we will demonstrate the high MPI tolerance of all-solid single-trench-assisted BIFs and UBIFs. We will present the first comprehensive study combining theoretical and experimental points of view to quantify the impact of fusion splices on coherent MPI. To be complete, results for mechanical splices will also be reported. Finally, we will show how the single-trench- assisted concept combined with the versatile PCVD process allows to tightly control the distributions of fibers characteristics. Such controls are needed to massively produce BIFs and to meet the more stringent specifications of the UBIFs.

Occipital bending in schizophrenia.

Science.gov (United States)

Maller, Jerome J; Anderson, Rodney J; Thomson, Richard H; Daskalakis, Zafiris J; Rosenfeld, Jeffrey V; Fitzgerald, Paul B

2017-01-01

To investigate the prevalence of occipital bending (an occipital lobe crossing or twisting across the midline) in subjects with schizophrenia and matched healthy controls. Occipital bending prevalence was investigated in 37 patients with schizophrenia and 44 healthy controls. Ratings showed that prevalence was nearly three times higher among schizophrenia patients (13/37 [35.1%]) than in control subjects (6/44 [13.6%]). Furthermore, those with schizophrenia had greater normalized gray matter volume but less white matter volume and had larger brain-to-cranial ratio. The results suggest that occipital bending is more prevalent among schizophrenia patients than healthy subjects and that schizophrenia patients have different gray matter-white matter proportions. Although the cause and clinical ramifications of occipital bending are unclear, the results infer that occipital bending may be a marker of psychiatric illness.

Development of vehicle model test-bending of a simple structural surfaces model for automotive vehicle sedan

Science.gov (United States)

Nor, M. K. Mohd; Noordin, A.; Ruzali, M. F. S.; Hussen, M. H.; Mustapa@Othman, N.

2017-04-01

Simple Structural Surfaces (SSS) method is offered as a means of organizing the process for rationalizing the basic vehicle body structure load paths. The application of this simplified approach is highly beneficial in the development of modern passenger car structure design. In Malaysia, the SSS topic has been widely adopted and seems compulsory in various automotive programs related to automotive vehicle structures in many higher education institutions. However, there is no real physical model of SSS available to gain considerable insight and understanding into the function of each major subassembly in the whole vehicle structures. Based on this motivation, a real physical SSS of sedan model and the corresponding model vehicle tests of bending is proposed in this work. The proposed approach is relatively easy to understand as compared to Finite Element Method (FEM). The results prove that the proposed vehicle model test is useful to physically demonstrate the importance of providing continuous load path using the necessary structural components within the vehicle structures. It is clearly observed that the global bending stiffness reduce significantly when more panels are removed from the complete SSS model. The analysis shows the front parcel shelf is an important subassembly to sustain bending load.

MRI shows thickening and altered diffusion in the median and ulnar nerves in multifocal motor neuropathy

DEFF Research Database (Denmark)

Haakma, Wieke; Jongbloed, Bas A.; Froeling, Martijn

2017-01-01

Objectives To study disease mechanisms in multifocal motor neuropathy (MMN) with magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) of the median and ulnar nerves. Methods We enrolled ten MMN patients, ten patients with amyotrophic lateral sclerosis (ALS) and ten healthy controls...

Explicit formulation of an anisotropic Allman/DKT 3-node thin triangular flat shell elements

Science.gov (United States)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular, flat shell element in global coordinates is presented. An Allman triangle is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending triangle. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, membrane and bending strain-displacement matrices.

Posttraumatic stiff elbow

Directory of Open Access Journals (Sweden)

Ravi Mittal

2017-01-01

Full Text Available Posttraumatic stiff elbow is a frequent and disabling complication and poses serious challenges for its management. In this review forty studies were included to know about the magnitude of the problem, causes, pathology, prevention, and treatment of posttraumatic stiff elbow. These studies show that simple measures such as internal fixation, immobilization in extension, and early motion of elbow joint are the most important steps that can prevent elbow stiffness. It also supports conservative treatment in selected cases. There are no clear guidelines about the choice between the numerous procedures described in literature. However, this review article disproves two major beliefs-heterotopic ossification is a bad prognostic feature, and passive mobilization of elbow causes elbow stiffness.

Neurotization of the biceps muscle by end-to-side neurorraphy between ulnar and musculocutaneous nerves. A series of five cases.

Science.gov (United States)

Franciosi, L F; Modestti, C; Mueller, S F

1998-01-01

Three patients with avulsed C5, C6, and C7 roots and two patients with avulsed C5 and C6 roots after trauma of the brachial plexus, were treated by neurotization of the biceps using nerve fibers derived from the ulnar nerve and obtained by end-to-side neurorraphy between the ulnar and musculocutaneous nerves. The age of patients ranged from 19 to 45. The interval between the accident and surgery was 2 to 13 months. Return of biceps contraction was observed 4 to 6 months after surgery. Four patients recovered grade 4 elbow flexion. One 45-year-old patient did not obtain any biceps contraction after 9 months.

A dissipated energy comparison to evaluate fatigue resistance using 2-point bending

Directory of Open Access Journals (Sweden)

Cinzia Maggiore

2014-02-01

Full Text Available Fatigue is the main failure mode in pavement engineering. Typically, micro-cracks originate at the bottom of asphalt concrete layer due to horizontal tensile strains. Micro-cracks start to propagate towards the upper layers under repeated loading which can lead to pavement failure. Different methods are usually used to describe fatigue behavior in asphalt materials such as: phenomenological approach, fracture mechanics approach and dissipated energy approach. This paper presents a comparison of fatigue resistances calculated for different dissipated energy models using 2-point bending (2PB at IFSTTAR in Nantes. 2PB tests have been undertaken under different loading and environmental conditions in order to evaluate the properties of the mixtures (stiffness, dissipated energy, fatigue life and healing effect.

A quantitative method for evaluating inferior glenohumeral joint stiffness using ultrasonography.

Science.gov (United States)

Tsai, Wen-Wei; Lee, Ming-Yih; Yeh, Wen-Lin; Cheng, Shih-Chung; Soon, Kok-Soon; Lei, Kin Fong; Lin, Wen-Yen

2013-02-01

and pain in the inferior GHJ at the loading point due to friction between the wide belt and skin. Furthermore, subjects wearing a humerus brace with a belt, which creates the effect of lifting the humerus toward the acromion, had greater GHJ stiffness compared to subjects wearing a shoulder brace without a belt to lift the humerus under the proposed testing conditions. This study provides experimental evidence that shoulder braces may reduce GHJ laxity under an external load, implying that the use of a humeral brace can prevent subluxation in post-stroke patients. The resulting optimal testing conditions for measuring the laxity and stiffness of the GHJ is to constrain the unloaded shoulder and bend the loaded arm at the elbow with loading on the upper arm using a pulley system. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

INDEX FINGER POSITION AND FORCE OF THE HUMAN FIRST DORSAL INTEROSSEUS AND ITS ULNAR NERVE ANTAGONIST

NARCIS (Netherlands)

ZIJDEWIND, Inge; KERNELL, D

In normal subjects, maximum voluntary contraction (MVC) and electrical ulnar nerve stimulation (UNS; 30-Hz bursts of 0.33 s) were systematically compared with regard to the forces generated in different directions (abduction/adduction and flexion) and at different degrees of index finger abduction.

Lipomatous macrodystrophy of the ulnar nerve: Role of magnetic resonance in the diagnosis

International Nuclear Information System (INIS)

Capelastegui, A.; Astigarraga, E.; Galan, V.

1996-01-01

Lipomatous macrodystrophy is a rare cause of macrodactyly that can be included among the bening adipose tissue tumors of the peripheral nerves. We present a case involving ulnar nerve, which is an unusual location since most of the reported cases correspond to median nerve. the magnetic resonance (MR) images are analyzed, and their role in the characterization and definition of the extension of these lesions is assessed. 4 refs

Radiocephalic Fistula Complicated by Distal Ischemia: Treatment by Ulnar Artery Dilatation

International Nuclear Information System (INIS)

Raynaud, Alain; Novelli, Luigi; Rovani, Xavier; Carreres, Thierry; Bourquelot, Pierre; Hermelin, Alain; Angel, C.; Beyssen, B.

2010-01-01

Hand ischemic steal syndrome due to a forearm arteriovenous fistula is a rare occurrence. However, its frequency is increasing with the rise in numbers of elderly and diabetic patients. This complication, which is more common for proximal than for distal accesses, can be very severe and may cause loss of hand function, damage to fingers, and even amputation of fingers or the hand. Its treatment is difficult and often leads to access loss. We report here a case of severe hand ischemia related to a radiocephalic fistula successfully treated by ulnar artery dilatation.

Validity of F-wave minimal latency of median and ulnar nerves for diagnosis and severity assessment of carpal tunnel syndrome in type II diabetes mellitus

International Nuclear Information System (INIS)

Hussain, A.; Habib, S.S.; Omar, S.A.; Drees, M.A.

2011-01-01

Type II diabetes mellitus is a common problem and is sometimes associated with Carpal Tunnel Syndrome (CTS) due to compression of median nerve at wrist. Electrophysiological tests are frequently used for its diagnosis. In this work, F-wave minimal latency (FWML) difference between median and ulnar nerve and F-ratio is used to facilitate the diagnosis and severity of CTS in type II diabetes mellitus (T2DM). Methods: Thirty control cases were selected who were physically fit for normal electrophysiological values. Thirty-two patients with a long history of type II diabetes mellitus were studied for electro-diagnostic tests. All patients had clinical evidence of CTS. Among all diabetics about 20 cases had poor glycaemic control (HbA1c>7.5). F-wave minimal latency (FWML) were measured in median and ulnar nerves and F-ratio of median nerve were also noted. The mean values in different groups were compared using t-test and p greater or equal to 0.05 was considered significant. Results: In control group, the ulnar FWML was either equal or slightly longer that the median FWML value. In CTS group with type II diabetes mellitus the FWML value of median nerve were significantly longer than FWML of the ulnar nerve. Moreover, in uncontrolled diabetic patients the FWML values was very much longer than controlled group. Similarly the F-ratio of median nerve was significantly low. Conclusion: In addition to the specific criteria for CTS diagnosis, the parameters like FWML difference in median and ulnar nerve with reduced F-ratio of median nerve can be useful in establishing the diagnosis and severity of CTS in type II diabetes mellitus. (author)

Arterial stiffness and cognitive impairment.

Science.gov (United States)

Li, Xiaoxuan; Lyu, Peiyuan; Ren, Yanyan; An, Jin; Dong, Yanhong

2017-09-15

Arterial stiffness is one of the earliest indicators of changes in vascular wall structure and function and may be assessed using various indicators, such as pulse-wave velocity (PWV), the cardio-ankle vascular index (CAVI), the ankle-brachial index (ABI), pulse pressure (PP), the augmentation index (AI), flow-mediated dilation (FMD), carotid intima media thickness (IMT) and arterial stiffness index-β. Arterial stiffness is generally considered an independent predictor of cardiovascular and cerebrovascular diseases. To date, a significant number of studies have focused on the relationship between arterial stiffness and cognitive impairment. To investigate the relationships between specific arterial stiffness parameters and cognitive impairment, elucidate the pathophysiological mechanisms underlying the relationship between arterial stiffness and cognitive impairment and determine how to interfere with arterial stiffness to prevent cognitive impairment, we searched PUBMED for studies regarding the relationship between arterial stiffness and cognitive impairment that were published from 2000 to 2017. We used the following key words in our search: "arterial stiffness and cognitive impairment" and "arterial stiffness and cognitive impairment mechanism". Studies involving human subjects older than 30years were included in the review, while irrelevant studies (i.e., studies involving subjects with comorbid kidney disease, diabetes and cardiac disease) were excluded from the review. We determined that arterial stiffness severity was positively correlated with cognitive impairment. Of the markers used to assess arterial stiffness, a higher PWV, CAVI, AI, IMT and index-β and a lower ABI and FMD were related to cognitive impairment. However, the relationship between PP and cognitive impairment remained controversial. The potential mechanisms linking arterial stiffness and cognitive impairment may be associated with arterial pulsatility, as greater arterial pulsatility

Bending the law: tidal bending and its effects on ice viscosity and flow

Science.gov (United States)

Rosier, S.; Gudmundsson, G. H.

2017-12-01

Many ice shelves are subject to strong ocean tides and, in order to accommodate this vertical motion, the ice must bend within the grounding zone. This tidal bending generates large stresses within the ice, changing its effective viscosity. For a confined ice shelf, this is particularly relevant because the tidal bending stresses occur along the sidewalls, which play an important role in the overall flow regime of the ice shelf. Hence, tidal bending stresses will affect both the mean and time-varying components of ice shelf flow. GPS measurements reveal strong variations in horizontal ice shelf velocities at a variety of tidal frequencies. We show, using full-Stokes viscoelastic modelling, that inclusion of tidal bending within the model accounts for much of the observed tidal modulation of horizontal ice shelf flow. Furthermore, our model shows that in the absence of a vertical tidal forcing, the mean flow of the ice shelf is reduced considerably.

Hypothenar hammer syndrome: long-term follow-up after ulnar artery reconstruction with the lateral circumflex femoral artery.

Science.gov (United States)

de Niet, A; Van Uchelen, J H

2017-06-01

In symptomatic patients with hypothenar hammer syndrome, the occluded part of the ulnar artery can be reconstructed with an autologous graft. Venous grafts are used frequently, but they are known for their low patency rate. Arterial grafts show better patency rates than venous grafts in coronary bypass surgery. We performed 11 ulnar artery reconstructions with the descending branch of the lateral circumflex femoral artery and compared these with previously performed venous reconstructions. All patients with an arterial graft reconstruction had a patent graft at a mean follow-up of 63 months. In addition, nine out of 11 patients reported improvement in their symptoms. The patency rate of venous reconstructions in hypothenar hammer syndrome is significantly lower. Arterial grafting for hypothenar hammer syndrome has superior patency compared with venous grafting; we recommend it as the surgical treatment of choice for symptomatic hypothenar hammer syndrome. 4.

A New Kind of Bend Sensor

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

A new kind of bend sensor is introduced.It can be used to detect the bend angle of an object or inclination between two objects.It has characteristics of small size, lightweight, high reliability, fine flexibility and plasticity.When this bend sensor is used with a proper converting circuit, it can implement dynamic measuring the bend angle of an object conveniently.The application of the bend sensor in dataglove is also described.

Estimating Gear Teeth Stiffness

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard

2013-01-01

The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffness’s of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact length is constant....

Effect of therapeutic ultrasound intensity on subcutaneous tissue temperature and ulnar nerve conduction velocity.

Science.gov (United States)

Kramer, J F

1985-02-01

Twenty subjects completed 5 min. periods of sonation, at each of six US intensities, over the ulnar nerve in the proximal forearm. All posttreatment NCV's differed significantly from the respective pretreatment velocities. The immediate posttreatment NCV associated with placebo US was significantly (p less than 0.01) less than that observed immediately pretreatment (2.81 m/s), while the five clinical US intensities produced significantly increased immediate posttreatment velocities: 0.5 w/cm2 (2.23 m/s) at (p less than 0.05), and 1.0 w/cm2 (2.78 m/s), 1.5 w/cm2 (3.15 m/s), 2.0 w/cm2 (4.47 m/s) and 2.5 w/cm2 (2.97 m/s) at (p less than 0.01). The posttreatment velocities associated with the five clinical intensities were all significantly greater (p less than 0.01) than that associated with placebo US. Subcutaneous tissue temperatures were directly related to the intensity of US. Not until US intensity had reached 1.5 w/cm2 did the heating effect of US negate the cooling effect of the US transmission gel, to produce significantly increased subcutaneous tissue temperatures after 5 min. sonation. The decreased ulnar motor NCV's associated with placebo US are attributed to the cooling effect of the US transmission gel. The increased ulnar motor NCV's associated with the clinical intensities of US are attributed to the deep heating effect of US. The breakdown of this linear relationship at 2.5 w/cm2 intensity suggests that at this point heating on the nerve and/or the mechanical effects of US were of sufficient magnitude so as to limit the increase in conduction velocity. Sonation over an area of approximately 4.5 times the soundhead for 5 min., along the proximal forearm, at clinical intensities did not have a bipositive effect on motor NCV.

The creep bending of short radius pipe bends

International Nuclear Information System (INIS)

Spence, John

1975-01-01

In existing and proposed liquid metal fast breeder reactor design the pipework has considerable importance. Parts of the LMFBR include thin walled short radius bends which are expected to operate in the creep regime. In linear elasticity it is known that the assumption of long radius bends is not too severe as far as the flexibility characteristics are concerned although some modifications are necessary for accurate determination of the stresses. No data exists for nonlinear creep. Current work is aimed at elucidating the effect of the various assumptions common to linear elastic theory in so far as they affect the creep characteristics of bends on systems. Herein an energy based analysis using a simple n power constitutive law for stationary creep is employed to derive basic design data for flexibilities and stresses which will be necessary before complete systems can be assessed for creep. The analysis shows on comparison with the long radius work that the assumption of R>r is not much more restrictive in creep than for linear elasticity. Flexibilities for short radius bends appear to be well approximated by the long radius values. Thus the attractive reference stress information already derived may be used directly to find deformations without a complete knowledge of the constitutive relationship. However, stresses are somewhat different. Fortunately the maximum deviation occurs at relatively low levels of stress, the peak stresses being in fair agreement. When n=1 the present results reduce essentially to those obtained from existing linear elastic theory

Resultado da neurotização do nervo ulnar para o músculo bíceps braquial na lesão do plexo braquial Results of ulnar nerve neurotization to brachial biceps muscle in brachial plexus injury

Directory of Open Access Journals (Sweden)

Marcelo Rosa de Rezende

2012-12-01

Full Text Available OBJETIVO: Avaliar de forma crítica os fatores que influenciam os resultados da neurotização do nervo ulnar no ramo motor do músculo bíceps braquial, visando a restauração da flexão do cotovelo em pacientes com lesão do plexo braquial. MÉTODOS: 19 pacientes, 18 homens e uma mulher, com idade média de 28,7 anos foram avaliados entre fevereiro de 2003 e maio de 2007. Oito pacientes apresentavam lesão das raízes C5-C6 e 11, das raízes C5-C6-C7. O intervalo de tempo médio entre a injúria e o tratamento cirúrgico foi 7,5 meses. Quatro pacientes apresentavam fraturas cervicais associadas à lesão do plexo braquial. O seguimento pós-operatório foi de 15,7 meses. RESULTADO: Oito pacientes recuperaram força de flexão do cotovelo MRC grau 4; dois, MRC grau 3 e nove, MRC OBJECTIVE: To evaluate the factors influencing the results of ulnar nerve neurotization at the motor branch of the brachial biceps muscle, aiming at the restoration of elbow flexion in patients with brachial plexus injury. METHODS: 19 patients, with 18 men and 1 woman, mean age 28.7 years. Eight patients had injury to roots C5-C6 and 11, to roots C5-C6-C7. The average time interval between injury and surgery was 7.5 months. Four patients had cervical fractures associated with brachial plexus injury. The postoperative follow-up was 15.7 months. RESULTS: Eight patients recovered elbow flexion strength MRC grade 4; two, MRC grade 3 and nine, MRC <3. There was no impairment of the previous ulnar nerve function. CONCLUSION: The surgical results of ulnar nerve neurotization at the motor branch of brachial biceps muscle are dependent on the interval between brachial plexus injury and surgical treatment, the presence of associated fractures of the cervical spine and occipital condyle, residual function of the C8-T1 roots after the injury and the involvement of the C7 root. Signs of reinnervation manifested up to 3 months after surgery showed better results in the long term

Trabecular meshwork stiffness in glaucoma.

Science.gov (United States)

Wang, Ke; Read, A Thomas; Sulchek, Todd; Ethier, C Ross

2017-05-01

Alterations in stiffness of the trabecular meshwork (TM) may play an important role in primary open-angle glaucoma (POAG), the second leading cause of blindness. Specifically, certain data suggest an association between elevated intraocular pressure (IOP) and increased TM stiffness; however, the underlying link between TM stiffness and IOP remains unclear and requires further study. We here first review the literature on TM stiffness measurements, encompassing various species and based on a number of measurement techniques, including direct approaches such as atomic force microscopy (AFM) and uniaxial tension tests, and indirect methods based on a beam deflection model. We also briefly review the effects of several factors that affect TM stiffness, including lysophospholipids, rho-kinase inhibitors, cytoskeletal disrupting agents, dexamethasone (DEX), transforming growth factor-β 2 (TGF-β 2 ), nitric oxide (NO) and cellular senescence. We then describe a method we have developed for determining TM stiffness measurement in mice using a cryosection/AFM-based approach, and present preliminary data on TM stiffness in C57BL/6J and CBA/J mouse strains. Finally, we investigate the relationship between TM stiffness and outflow facility between these two strains. The method we have developed shows promise for further direct measurements of mouse TM stiffness, which may be of value in understanding mechanistic relations between outflow facility and TM biomechanical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

A variable stiffness joint with electrospun P(VDF-TrFE-CTFE) variable stiffness springs

NARCIS (Netherlands)

Carloni, Raffaella; Lapp, Valerie I.; Cremonese, Andrea; Belcari, Juri; Zucchelli, Andrea

This letter presents a novel rotational variable stiffness joint that relies on one motor and a set of variable stiffness springs. The variable stiffness springs are leaf springs with a layered design, i.e., an electro-active layer of electrospun aligned nanofibers of poly(vinylidene

Pharmacological modulation of arterial stiffness.

LENUS (Irish Health Repository)

Boutouyrie, Pierre

2011-09-10

Arterial stiffness has emerged as an important marker of cardiovascular risk in various populations and reflects the cumulative effect of cardiovascular risk factors on large arteries, which in turn is modulated by genetic background. Arterial stiffness is determined by the composition of the arterial wall and the arrangement of these components, and can be studied in humans non-invasively. Age and distending pressure are two major factors influencing large artery stiffness. Change in arterial stiffness with drugs is an important endpoint in clinical trials, although evidence for arterial stiffness as a therapeutic target still needs to be confirmed. Drugs that independently affect arterial stiffness include antihypertensive drugs, mostly blockers of the renin-angiotensin-aldosterone system, hormone replacement therapy and some antidiabetic drugs such as glitazones. While the quest continues for \\'de-stiffening drugs\\

[False traumatic aneurysm of the ulnar artery in a teenager].

Science.gov (United States)

Nour, M; Talha, H; El Idrissi, R; Lahraoui, Y; Ouazzani, L; Oubejja, H; Erraji, M; Zerhouni, H; Ettayebi, F

2014-12-01

Most aneurysms of hand arteries are traumatic. It is a generally rare unrecognized pathology. Complications are serious (embolism and thromboses of interdigital arteries). Two main causes can be recalled: acute trauma, with development of a false aneurysm; repeated microtrauma (hand hammer syndrome), with occurrence of an arterial dysplasic aneurysm. The diagnosis is based on the presence of a pulsatile mass, with finger dysesthesia, unilateral Raynaud's phenomenon. It is confirmed by duplex Doppler. Arteriography is necessary but can be replaced by an angio-MR. We report a case of false traumatic aneurysm of the ulnar artery in a teenager. This case illustrates this rare condition and opens discussion on therapeutic options. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Limit loads for pipe bends under combined pressure and in-plane bending based on finite element limit analysis

International Nuclear Information System (INIS)

Oh, Chang Sik; Kim, Yun Jae

2006-01-01

In the present paper, approximate plastic limit load solutions for pipe bends under combined internal pressure and bending are obtained from detailed three-dimensional (3-D) FE limit analyses based on elastic-perfectly plastic materials with the small geometry change option. The present FE results show that existing limit load solutions for pipe bends are lower bounds but can be very different from the present FE results in some cases, particularly for bending. Accordingly closed-form approximations are proposed for pipe bends under combined pressure and in-plane bending based on the present FE results. The proposed limit load solutions would be a basis of defective pipe bends and be useful to estimate non-linear fracture mechanics parameters based on the reference stress approach

Measurement and Treatment of Passive Muscle Stiffness

DEFF Research Database (Denmark)

Kirk, Henrik

, which aimed to investigate: 1) The development of a clinical method to evaluate and distinguish neural (reflex mediated stiffness) and non-neural (passive muscle stiffness) components of muscle stiffness in adults with CP by objective and reliable measurements. 2) The association between increased...... and reliability of the method, and argue for the use of the method in the clinical practice. The device is able to distinguish between passive muscle stiffness and reflex-mediated stiffness in subjects with CP. It shows good high intrarater and interrater reliability in evaluation of passive muscle stiffness...... to measure muscle stiffness, and distinguish between passive muscle stiffness and reflex-mediated stiffness. Furthermore, it is a reliable device to measure changes in passive ROM. Treatment of passive muscle stiffness should be directed towards intense training, comprising many repetitions with a functional...

Injury to ulnar collateral ligament of thumb.

Science.gov (United States)

Madan, Simerjit Singh; Pai, Dinker R; Kaur, Avneet; Dixit, Ruchita

2014-02-01

Injury of the ulnar collateral ligament (UCL) of thumb can be incapacitating if untreated or not treated properly. This injury is notorious for frequently being missed by inexperienced health care personnel in emergency departments. It has frequently been described in skiers, but also occurs in other sports such as rugby, soccer, handball, basketball, volleyball and even after a handshake. The UCL of the thumb acts as a primary restraint to valgus stress and is injured if hyperabduction and hyperextension forces are applied to the first metacarpophalangeal joint. The diagnosis is best established clinically, though MRI is the imaging modality of choice. Many treatment options exist, surgical treatment being offered depending on various factors, including timing of presentation (acute or chronic), grade (severity of injury), displacement (Stener lesion), location of tear (mid-substance or peripheral), associated or concomitant surrounding tissue injury (bone, volar plate, etc.), and patient-related factors (occupational demands, etc.). This review aims to identify the optimal diagnostic techniques and management options for UCL injury available thus far. © 2014 Chinese Orthopaedic Association and Wiley Publishing Asia Pty Ltd.

Bending stress modeling of dismountable furniture joints applied with a use of finite element method

Directory of Open Access Journals (Sweden)

Milan Šimek

2009-01-01

Full Text Available Presented work focuses on bending moment stress modeling of dismountable furniture joints with a use of Finite Element Method. The joints are created from Minifix and Rondorfix cams combined with non-glued wooden dowels. Laminated particleboard 18 mm of thickness is used as a connected material. The connectors were chosen such as the most applied kind in furniture industry for the case furniture. All gained results were reciprocally compared to each other and also in comparison to experimental testing by the mean of stiffness. The non-linear numerical model of chosen joints was successfully created using the software Ansys Workbench. The detailed analysis of stress distribution in the joint was achieved with non-linear numerical simulation. A relationship between numerical si­mu­la­tion and experimental testing was showed by comparison stiffness tangents. A numerical simulation of RTA joint loads also demonstrated the important role of non-glued dowels in the tested joints. The low strength of particleboard in the tension parallel to surface (internal bond is the most likely the cause of the joint failure. Results are applicable for strength designing of furniture with the aid of Computer Aided Engineering.

On gear tooth stiffness evaluation

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard; Jørgensen, Martin Felix

2014-01-01

The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...

Novel quadrilateral elements based on explicit Hermite polynomials for bending of Kirchhoff-Love plates

Science.gov (United States)

Beheshti, Alireza

2018-03-01

The contribution addresses the finite element analysis of bending of plates given the Kirchhoff-Love model. To analyze the static deformation of plates with different loadings and geometries, the principle of virtual work is used to extract the weak form. Following deriving the strain field, stresses and resultants may be obtained. For constructing four-node quadrilateral plate elements, the Hermite polynomials defined with respect to the variables in the parent space are applied explicitly. Based on the approximated field of displacement, the stiffness matrix and the load vector in the finite element method are obtained. To demonstrate the performance of the subparametric 4-node plate elements, some known, classical examples in structural mechanics are solved and there are comparisons with the analytical solutions available in the literature.

Dynamic stiffness of suction caissons

DEFF Research Database (Denmark)

Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

Surface effects on static bending of nanowires based on non-local elasticity theory

Directory of Open Access Journals (Sweden)

Quan Wu

2015-10-01

Full Text Available The surface elasticity and non-local elasticity effects on the elastic behavior of statically bent nanowires are investigated in the present investigation. Explicit solutions are presented to evaluate the surface stress and non-local elasticity effects with various boundary conditions. Compared with the classical Euler beam, a nanowire with surface stress and/or non-local elasticity can be either stiffer or less stiff, depending on the boundary conditions. The concept of surface non-local elasticity was proposed and its physical interpretation discussed to explain the combined effect of surface elasticity and non-local elasticity. The effect of the nanowire size on its elastic bending behavior was investigated. The results obtained herein are helpful to characterize mechanical properties of nanowires and aid nanowire-based devices design.

Rupture prediction for induction bends under opening mode bending with emphasis on strain localization

International Nuclear Information System (INIS)

Mitsuya, Masaki; Sakanoue, Takashi

2015-01-01

This study focuses on the opening mode of induction bends; this mode represents the deformation outside a bend. Bending experiments on induction bends are shown and the manner of failure of these bends was investigated. Ruptures occur at the intrados of the bends, which undergo tensile stress, and accompany the local reduction of wall thickness, i.e., necking that indicates strain localization. By implementing finite element analysis (FEA), it was shown that the rupture is dominated not by the fracture criterion of material but by the initiation of strain localization that is a deformation characteristic of the material. These ruptures are due to the rapid increase of local strain after the initiation of strain localization and suddenly reach the fracture criterion. For the evaluation of the deformability of the bends, a method based on FEA that can predict the displacement at the rupture is proposed. We show that the yield surface shape and the true stress–strain relationship after uniform elongation have to be defined on the basis of the actual properties of the bend material. The von Mises yield criterion, which is commonly used in cases of elastic–plastic FEA, could not predict the rupture and overestimated the deformability. In contrast, a yield surface obtained by performing tensile tests on a biaxial specimen could predict the rupture. The prediction of the rupture was accomplished by an inverse calibration method that determined the true stress-strain relationship after uniform elongation. As an alternative to the inverse calibration, a simple extrapolation method of the true stress-strain relationship after uniform elongation which can predict the rupture is proposed. - Highlights: • A method based on FEA that can predict the displacement at the rupture is proposed. • The yield surface shape and the true stress–strain have to be defined precisely. • The von Mises yield criterion overestimated the deformability. • The ruptures are due to the

LSODE, 1. Order Stiff or Non-Stiff Ordinary Differential Equations System Initial Value Problems

International Nuclear Information System (INIS)

Hindmarsh, A.C.; Petzold, L.R.

2005-01-01

1 - Description of program or function: LSODE (Livermore Solver for Ordinary Differential Equations) solves stiff and non-stiff systems of the form dy/dt = f. In the stiff case, it treats the Jacobian matrix df/dy as either a dense (full) or a banded matrix, and as either user-supplied or internally approximated by difference quotients. It uses Adams methods (predictor-corrector) in the non-stiff case, and Backward Differentiation Formula (BDF) methods (the Gear methods) in the stiff case. The linear systems that arise are solved by direct methods (LU factor/solve). The LSODE source is commented extensively to facilitate modification. Both a single-precision version and a double-precision version are available. 2 - Methods: It is assumed that the ODEs are given explicitly, so that the system can be written in the form dy/dt = f(t,y), where y is the vector of dependent variables, and t is the independent variable. LSODE contains two variable-order, variable- step (with interpolatory step-changing) integration methods. The first is the implicit Adams or non-stiff method, of orders one through twelve. The second is the backward differentiation or stiff method (or BDF method, or Gear's method), of orders one through five. 3 - Restrictions on the complexity of the problem: The differential equations must be given in explicit form, i.e., dy/dt = f(y,t). Problems with intermittent high-speed transients may cause inefficient or unstable performance

Bend me, shape me

CERN Multimedia

2002-01-01

A Japanese team has found a way to bend and shape silicon substrates by growing a thin layer of diamond on top. The technique has been proposed as an alternative to mechanical bending, which is currently used to make reflective lenses for X-ray systems and particle physics systems (2 paragraphs).

Transfixation pinning and casting of radial-ulnar fractures in calves: A review of three cases

OpenAIRE

St-Jean, Guy; Debowes, Richard M.

1992-01-01

We reviewed the medical records of three calves with radial-ulnar fractures which were reduced and stabilized by transfixation pinning and casting. Multiple Steinmann pins were placed transversely through proximal and distal fracture fragments and the pin ends were incorporated in fiberglass cast material after fracture reduction. Cast material was placed from proximal to distal radius and served as an external frame to maintain pin position and fracture reduction.

On the accuracy of analyses for in-plane bending of smooth pipe bends with end constraints

International Nuclear Information System (INIS)

Thomson, G.; Spence, J.

1985-01-01

The accuracy of theoretical analyses for in-plane bending of smooth pipebends with end constraints is discussed and investigated with a view to explaining and reducing the differences between the major works. An earlier theory of the authors is improved to give more accurate answers for bends with rigid flanges. Flanged bends are then examined in some detail, quantifying for the first time the important influence of the flange rigidity on the bend flexibility and stresses. A summary of some finite element analyses is presented from which it is clear that further work is desirable. (orig.)

Prevalence of ulnar-to-median nerve motor fiber anastomosis (Riché-Cannieu communicating branch) in hand: An electrophysiological study

Science.gov (United States)

Ahadi, Tannaz; Raissi, Gholam Reza; Yavari, Masood; Majidi, Lobat

2016-01-01

Background: Two main muscles studied in the hand for evaluation of median nerve injuries are opponens pollicis (OP) and abductor pollicis brevis (APB). However, Riché-Cannieu communicating branch (RCCB) may limit the use of these muscles in electrodiagnosis. This condition is confusing in the case of median nerve injuries. This study was conducted to evaluate the prevalence of RCCB. Methods: Twenty-three consecutive cases of complete median nerve injury were studied. Evoked responses via stimulation of median and ulnar nerves in the wrist and recording with needle in the thenar area were studied. Results: Of the patients, 82.6% exhibited RCCB. In 14 (60.8%) cases the OP and in 19(82.6%) cases APB was supplied by the ulnar nerve. Conclusion: RCCB was detected to be 60.8% in OP and 82.6% in APB, so OP is preferable to APB in the study of median nerve. PMID:27390694

Effect of bend separation distance on the mass transfer in back-to-back pipe bends arranged in a 180° configuration

Science.gov (United States)

Chen, X.; Le, T.; Ewing, D.; Ching, C. Y.

2016-12-01

The mass transfer to turbulent flow through back-to-back pipe bends arranged in a 180° configuration with different lengths of pipe between the bends was measured using a dissolving gypsum test section in water. The measurements were performed for bends with a radius of curvature of 1.5 times the pipe diameter ( D) at a Reynolds numbers of 70,000 and Schmidt number of 1280. The maximum mass transfer in the bends decreased from approximately 1.8 times the mass transfer in the upstream pipe when there was no separation distance between the bends to 1.7 times when there was a 1 D or 5 D length of pipe between the bends. The location of the maximum mass transfer was on the inner sidewall downstream of the second bend when there was no separation distance between the bends. This location changed to the inner wall at the beginning of the second bend when there was a 1 D long pipe between the bends, and to the inner sidewall at the end of the first bend when there was a 5 D long pipe between the bends.

Bend testing for miniature disks

International Nuclear Information System (INIS)

Huang, F.H.; Hamilton, M.L.; Wire, G.L.

1982-01-01

A bend test was developed to obtain ductility measurements on a large number of alloy variants being irradiated in the form of miniature disks. Experimental results were shown to be in agreement with a theoretical analysis of the bend configuration. Disk specimens fabricated from the unstrained grip ends of previously tested tensile specimens were used for calibration purposes; bend ductilities and tensile ductilities were in good agreement. The criterion for estimating ductility was judged acceptable for screening purposes

Fabrication of topology optimized photonic crystal waveguide Z-bend displaying large bandwidth with very low bend loss

DEFF Research Database (Denmark)

Harpøth, Anders; Frandsen, Lars Hagedorn; Kristensen, Martin

2004-01-01

We have designed, simulated and fabricated a photonic crystal waveguide Z-bend, which displays a total bend loss of ~1dB per bend in a wavelength range of more than 200nm. The fabricated component performs in excellent agreement with 3D finite-difference time-domain calculations....

Properties and determination of the interface stiffness

International Nuclear Information System (INIS)

Du Danxu; Zhang Hao; Srolovitz, David J.

2007-01-01

The chemical potential of a curved interface contains a term that is proportional to the product of the interface curvature and the interface stiffness. In crystalline materials, the interface stiffness is a tensor. This paper examines several basic issues related to the properties of the interface stiffness, especially the determination of the interface stiffness in particular directions (i.e. the commonly used scalar form of the interface stiffness). Of the five parameters that describe an arbitrary grain boundary, only those describing the inclination are crucial for the scalar stiffness. We also examine the influence of crystal symmetry on the stiffness tensor for both free surfaces and grain boundaries. This results in substantial simplifications for cases in which interfaces possess mirror or rotational symmetries. An efficient method for determining the interface stiffness tensor using atomistic simulations is proposed

76 FR 81992 - PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption

Science.gov (United States)

2011-12-29

... License Application for Bell Bend Nuclear Power Plant; Exemption 1.0 Background PPL Bell Bend, LLC... for Nuclear Power Plants.'' This reactor is to be identified as Bell Bend Nuclear Power Plant (BBNPP... based upon the U.S. EPR reference COL (RCOL) application for UniStar's Calvert Cliffs Nuclear Power...

Recovery from distal ulnar motor conduction block injury: serial EMG studies.

Science.gov (United States)

Montoya, Liliana; Felice, Kevin J

2002-07-01

Acute conduction block injuries often result from nerve compression or trauma. The temporal pattern of clinical, electrophysiologic, and histopathologic changes following these injuries has been extensively studied in experimental animal models but not in humans. Our recent evaluation of a young man with an injury to the deep motor branch of the ulnar nerve following nerve compression from weightlifting exercises provided the opportunity to follow the course and recovery of a severe conduction block injury with sequential nerve conduction studies. The conduction block slowly and completely resolved, as did the clinical deficit, over a 14-week period. The reduction in conduction block occurred at a linear rate of -6.1% per week. Copyright 2002 Wiley Periodicals, Inc.

A transparent bending-insensitive pressure sensor

Science.gov (United States)

Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

2016-05-01

Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

Application of monosymmetrical I-beams in light metal frames with variable stiffness

Directory of Open Access Journals (Sweden)

I.O. Sklyarov

2016-05-01

Full Text Available The article is devoted to effectiveness of using of monosymmetrical I-beams with flexible wall frame structures of variable section, features of their calculation and design. Aim: The aim of research is to confirm the feasibility of I-beams with flexible wall bearing as light metal skeletons for buildings of the universal assignment. Materials and Methods: In order to reduce the metal consumption a frame is conventionally divided into several sections according to bending moment diagrams so that in the more compressed zone section the belt of great area was located, and in the stretched or less intense zone the lesser belt was installed. The resulting sections have smaller area in compare to symmetric profiles. Additional reduce bending moments provided as a result of displacement of elements axes with variable cross section. Results: The calculations and selection of sections of the frame have shown that it can be achieved the reducing of bearing elements weight by 10% compared to the symmetrical profiles of variable stiffness due to using monosymmetrical sections. The effectiveness of the proposed constructive solution is confirmed by compare of the projected weight frame construction with existing analogue. The symmetrical frame profile is 15.3% lighter; the monosymmetrical frame profile is 27% lighter. Conclusions: Analysis of stress-strain state structures shown: first, through asymmetrical profile there is a shifting of the center of gravity section, which leads to a redistribution of internal forces in the frame; secondly, because of the small cross-sectional area of the stretched zones more difficult to ensure the stability of the plane form of bending beams, which leads to the necessity to disconnect areas curtain beams by constraints of smaller steps.

A Novel Variable Stiffness Mechanism Capable of an Infinite Stiffness Range and Unlimited Decoupled Output Motion

Directory of Open Access Journals (Sweden)

Stefan Groothuis

2014-06-01

Full Text Available In this paper, a novel variable stiffness mechanism is presented, which is capable of achieving an output stiffness with infinite range and an unlimited output motion, i.e., the mechanism output is completely decoupled from the rotor motion, in the zero stiffness configuration. The mechanism makes use of leaf springs, which are engaged at different positions by means of two movable supports, to realize the variable output stiffness. The Euler–Bernoulli leaf spring model is derived and validated through experimental data. By shaping the leaf springs, it is shown that the stiffness characteristic of the mechanism can be changed to fulfill different application requirements. Alternative designs can achieve the same behavior with only one leaf spring and one movable support pin.

Stiffness of desiccating insect wings

International Nuclear Information System (INIS)

Mengesha, T E; Vallance, R R; Mittal, R

2011-01-01

The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 μN mm -1 h -1 . For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm -1 . (communication)

Stiffness of desiccating insect wings

Energy Technology Data Exchange (ETDEWEB)

Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: vallance@gwu.edu [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)

2011-03-15

The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

Shoulder Stiffness : Current Concepts and Concerns

NARCIS (Netherlands)

Itoi, Eiji; Arce, Guillermo; Bain, Gregory I.; Diercks, Ronald L.; Guttmann, Dan; Imhoff, Andreas B.; Mazzocca, Augustus D.; Sugaya, Hiroyuki; Yoo, Yon-Sik

Shoulder stiffness can be caused by various etiologies such as immobilization, trauma, or surgical interventions. The Upper Extremity Committee of ISAKOS defined the term "frozen shoulder" as idiopathic stiff shoulder, that is, without a known cause. Secondary stiff shoulder is a term that should be

Diagnostic Performance of the Extensor Carpi Ulnaris (ECU) Synergy Test to Detect Sonographic ECU Abnormalities in Chronic Dorsal Ulnar-Sided Wrist Pain.

Science.gov (United States)

Sato, Junko; Ishii, Yoshinori; Noguchi, Hideo

2016-01-01

The extensor carpi ulnaris (ECU) tendon synergy test is a simple and unique diagnostic maneuver for evaluation of chronic dorsal ulnar-sided wrist pain, which applies isolated tension to the ECU without greatly stressing other structures. This study aimed to investigate the diagnostic performance of the ECU synergy test to detect ECU abnormalities on sonography. Forty affected wrists from 39 consecutive patients with chronic dorsal ulnar-sided wrist pain that continued for greater than 1 month were examined with the ECU synergy test and sonography. The sensitivity, specificity, positive predictive value, and negative predictive value of the ECU synergy test to detect ECU abnormalities were evaluated. We compared the results of the ECU synergy test between groups with and without ECU abnormalities and also compared the ages, sexes, and symptomatic durations of the patients between groups with positive and negative ECU synergy test results and between the groups with and without ECU abnormalities. The sensitivity, specificity, positive predictive value, and negative predictive value were 73.7%, 85.7%, 82.4%, and 78.3%, respectively. There was significant difference in the ECU synergy test results between the groups with and without ECU abnormalities (P synergy test could be a useful provocative maneuver to detect ECU abnormalities in patients with chronic dorsal ulnar-sided wrist pain. © 2016 by the American Institute of Ultrasound in Medicine.

The link between exercise and titin passive stiffness.

Science.gov (United States)

Lalande, Sophie; Mueller, Patrick J; Chung, Charles S

2017-09-01

What is the topic of this review? This review focuses on how in vivo and molecular measurements of cardiac passive stiffness can predict exercise tolerance and how exercise training can reduce cardiac passive stiffness. What advances does it highlight? This review highlights advances in understanding the relationship between molecular (titin-based) and in vivo (left ventricular) passive stiffness, how passive stiffness modifies exercise tolerance, and how exercise training may be therapeutic for cardiac diseases with increased passive stiffness. Exercise can help alleviate the negative effects of cardiovascular disease and cardiovascular co-morbidities associated with sedentary behaviour; this may be especially true in diseases that are associated with increased left ventricular passive stiffness. In this review, we discuss the inverse relationship between exercise tolerance and cardiac passive stiffness. Passive stiffness is the physical property of cardiac muscle to produce a resistive force when stretched, which, in vivo, is measured using the left ventricular end diastolic pressure-volume relationship or is estimated using echocardiography. The giant elastic protein titin is the major contributor to passive stiffness at physiological muscle (sarcomere) lengths. Passive stiffness can be modified by altering titin isoform size or by post-translational modifications. In both human and animal models, increased left ventricular passive stiffness is associated with reduced exercise tolerance due to impaired diastolic filling, suggesting that increased passive stiffness predicts reduced exercise tolerance. At the same time, exercise training itself may induce both short- and long-term changes in titin-based passive stiffness, suggesting that exercise may be a treatment for diseases associated with increased passive stiffness. Direct modification of passive stiffness to improve exercise tolerance is a potential therapeutic approach. Titin passive stiffness itself may

Interfascicular suture with nerve autografts for median, ulnar and radial nerve lesions.

Science.gov (United States)

Pluchino, F; Luccarelli, G

1981-05-01

Interfascicular nerve suture with autografts is the operation of choice for repairing peripheral nerve injuries because it ensures more precise alignment of the fasciculi and so better chances of reinnervation of the sectioned nerve. The procedure as described by Millesi et al has been used at the Istituto Neurologico di Milano in 30 patients with traumatic lesions of the median, ulnar and radial nerves. All have been followed up for 2 to 7 years since operation. The results obtained are compared with those of other series obtained with interfascicular suture and with epineural suture. Microsurgery is essential. The best time to operate is discussed.

Efficient Method for Calculating the Composite Stiffness of Parabolic Leaf Springs with Variable Stiffness for Vehicle Rear Suspension

Directory of Open Access Journals (Sweden)

Wen-ku Shi

2016-01-01

Full Text Available The composite stiffness of parabolic leaf springs with variable stiffness is difficult to calculate using traditional integral equations. Numerical integration or FEA may be used but will require computer-aided software and long calculation times. An efficient method for calculating the composite stiffness of parabolic leaf springs with variable stiffness is developed and evaluated to reduce the complexity of calculation and shorten the calculation time. A simplified model for double-leaf springs with variable stiffness is built, and a composite stiffness calculation method for the model is derived using displacement superposition and material deformation continuity. The proposed method can be applied on triple-leaf and multileaf springs. The accuracy of the calculation method is verified by the rig test and FEA analysis. Finally, several parameters that should be considered during the design process of springs are discussed. The rig test and FEA analytical results indicate that the calculated results are acceptable. The proposed method can provide guidance for the design and production of parabolic leaf springs with variable stiffness. The composite stiffness of the leaf spring can be calculated quickly and accurately when the basic parameters of the leaf spring are known.

Occipital bending in depression.

Science.gov (United States)

Maller, Jerome J; Thomson, Richard H S; Rosenfeld, Jeffrey V; Anderson, Rodney; Daskalakis, Zafiris J; Fitzgerald, Paul B

2014-06-01

There are reports of differences in occipital lobe asymmetry within psychiatric populations when compared with healthy control subjects. Anecdotal evidence and enlarged lateral ventricles suggests that there may also be a different pattern of curvature whereby one occipital lobe wraps around the other, termed 'occipital bending'. We investigated the prevalence of occipital bending in 51 patients with major depressive disorder (males mean age = 41.96 ± 14.00 years, females mean age = 40.71 ± 12.41 years) and 48 age- and sex-matched healthy control subjects (males mean age = 40.29 ± 10.23 years, females mean age = 42.47 ± 14.25 years) and found the prevalence to be three times higher among patients with major depressive disorder (18/51, 35.3%) when compared with control subjects (6/48, 12.5%). The results suggest that occipital bending is more common among patients with major depressive disorder than healthy subjects, and that occipital asymmetry and occipital bending are separate phenomena. Incomplete neural pruning may lead to the cranial space available for brain growth being restricted, or ventricular enlargement may exacerbate the natural occipital curvature patterns, subsequently causing the brain to become squashed and forced to 'wrap' around the other occipital lobe. Although the clinical implications of these results are unclear, they provide an impetus for further research into the relevance of occipital bending in major depression disorder. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Relative Contribution to Small Finger Abduction of the Ulnar Versus Radial Slip of the EDM: Implications for Tendon Transfers.

Science.gov (United States)

Akinleye, Sheriff D; Culbertson, Maya Deza; Cappelleti, Giacomo; Garofolo, Garret; Choueka, Jack

2017-09-01

The extensor digiti minimi (EDM) tendon is commonly divided into a radial slip (EDM-R) and an ulnar slip (EDM-U). To our knowledge, the degree to which each EDM slip concomitantly abducts the small finger with active extension has not been formally tested. This study sought to characterize the comparative contributions of finger abduction inherent to each slip of the EDM to observe the sequelae of active small finger extension following transfer of the contralateral slip. Eighteen fresh-frozen cadaveric hands were used in this study. Starting with the hand in resting position, a controlled traction of 10 N was applied to each slip of the EDM tendon. The range of small finger abduction with respect to the fixed ring finger was recorded utilizing infrared reflective markers tracked through the range of motion using a digital video camera. The mean abduction of the small finger when the radial slip of the EDM tendon was tested was 13.33° (95% confidence interval [CI]: 10.10°-16.55°), which was significantly different ( P ≤ .001) than small finger abduction produced by the ulnar slip of the EDM, with a mean of 23.72° (95% CI: 19.40°-28.04°). Given the fact that the ulnar slip of the EDM tendon is shown to be the major contributor of aberrant abduction with active small finger extension, as traction on this slip produces almost twice as much abduction as the radial slip, the EDM-U is the ideal donor graft with respect to tendon transfers of the EDM.

Hydration Status Is Associated with Aortic Stiffness, but Not with Peripheral Arterial Stiffness, in Chronically Hemodialysed Patients

Directory of Open Access Journals (Sweden)

Daniel Bia

2015-01-01

Full Text Available Background. Adequate fluid management could be essential to minimize high arterial stiffness observed in chronically hemodialyzed patients (CHP. Aim. To determine the association between body fluid status and central and peripheral arterial stiffness levels. Methods. Arterial stiffness was assessed in 65 CHP by measuring the pulse wave velocity (PWV in a central arterial pathway (carotid-femoral and in a peripheral pathway (carotid-brachial. A blood pressure-independent regional arterial stiffness index was calculated using PWV. Volume status was assessed by whole-body multiple-frequency bioimpedance. Patients were first observed as an entire group and then divided into three different fluid status-related groups: normal, overhydration, and dehydration groups. Results. Only carotid-femoral stiffness was positively associated (P<0.05 with the hydration status evaluated through extracellular/intracellular fluid, extracellular/Total Body Fluid, and absolute and relative overhydration. Conclusion. Volume status and overload are associated with central, but not peripheral, arterial stiffness levels with independence of the blood pressure level, in CHP.

Analysis of thin-walled cylindrical composite shell structures subject to axial and bending loads: Concept development, analytical modeling and experimental verification

Science.gov (United States)

Mahadev, Sthanu

Continued research and development efforts devoted in recent years have generated novel avenues towards the advancement of efficient and effective, slender laminated fiber-reinforced composite members. Numerous studies have focused on the modeling and response characterization of composite structures with particular relevance to thin-walled cylindrical composite shells. This class of shell configurations is being actively explored to fully determine their mechanical efficacy as primary aerospace structural members. The proposed research is targeted towards formulating a composite shell theory based prognosis methodology that entails an elaborate analysis and investigation of thin-walled cylindrical shell type laminated composite configurations that are highly desirable in increasing number of mechanical and aerospace applications. The prime motivation to adopt this theory arises from its superior ability to generate simple yet viable closed-form analytical solution procedure to numerous geometrically intense, inherent curvature possessing composite structures. This analytical evaluative routine offers to acquire a first-hand insight on the primary mechanical characteristics that essentially govern the behavior of slender composite shells under typical static loading conditions. Current work exposes the robustness of this mathematical framework via demonstrating its potential towards the prediction of structural properties such as axial stiffness and bending stiffness respectively. Longitudinal ply-stress computations are investigated upon deriving the global stiffness matrix model for composite cylindrical tubes with circular cross-sections. Additionally, this work employs a finite element based numerical technique to substantiate the analytical results reported for cylindrically shaped circular composite tubes. Furthermore, this concept development is extended to the study of thin-walled, open cross-sectioned, curved laminated shells that are geometrically

Median and Ulnar Neuropathy Assessment in Parkinson’s Disease regarding Symptom Severity and Asymmetry

Directory of Open Access Journals (Sweden)

Nilgul Yardimci

2016-01-01

Full Text Available Background. While increasing evidence suggests comorbidity of peripheral neuropathy (PNP and Parkinson’s disease (PD, the pathogenesis of PNP in PD is still a debate. The aim of this article is to search the core PD symptoms such as rigidity and tremor as contributing factors to mononeuropathy development while emphasizing each individual patient’s asymmetric symptom severity. Methods. We studied 62 wrists and 62 elbows of 31 patients (mean age 66.48±10.67 and 64 wrists and 64 elbows of 32 age-gender matched healthy controls (mean age 62.03±10.40, p=0.145. The Hoehn and Yahr disability scale and Unified Parkinson’s Disease Rated Scale were used to determine the severity of the disease. Results. According to electrodiagnostic criteria, we confirmed median neuropathy in 16.12% (bilateral in two-thirds of the patients and ulnar neuropathy in 3.22% of the PD group. While mean age (p=0.003, age at PD onset (p=0.019, and H&Y scores (p=0.016 were significant, tremor and rigidity scores were not. The comparison of the mean indices of electrophysiologic parameters indicated subclinical median and ulnar nerve demyelination both at the wrist and at the elbow in the patient groups where a longer disease duration and mild tremor and rigidity scores are prominent, remarkably. Conclusion. A disease related peripheral neurodegeneration beyond symptom severity occurs in PD.

VCODE, Ordinary Differential Equation Solver for Stiff and Non-Stiff Problems

International Nuclear Information System (INIS)

Cohen, Scott D.; Hindmarsh, Alan C.

2001-01-01

1 - Description of program or function: CVODE is a package written in ANSI standard C for solving initial value problems for ordinary differential equations. It solves both stiff and non stiff systems. In the stiff case, it includes a variety of options for treating the Jacobian of the system, including dense and band matrix solvers, and a preconditioned Krylov (iterative) solver. 2 - Method of solution: Integration is by Adams or BDF (Backward Differentiation Formula) methods, at user option. Corrector iteration is by functional iteration or Newton iteration. For the solution of linear systems within Newton iteration, users can select a dense solver, a band solver, a diagonal approximation, or a preconditioned Generalized Minimal Residual (GMRES) solver. In the dense and band cases, the user can supply a Jacobian approximation or let CVODE generate it internally. In the GMRES case, the pre-conditioner is user-supplied

Reliability of non-heated tube bends of boilers

International Nuclear Information System (INIS)

Bugaj, N.V.; Akhremenko, V.L.; Zamotaev, V.S.

1984-01-01

Bend failures are described for non-heated boiler tubes of 12Kh1MF and 20 steels. Methods of reliability evaluations are presented which permit revealing and replacing the bends with inadequate resources. Influences of operation conditions on bend durability is shown as well as the factors which are dominating at bend failures

Bending sound in graphene: Origin and manifestation

Energy Technology Data Exchange (ETDEWEB)

Adamyan, V.M., E-mail: vadamyan@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Bondarev, V.N., E-mail: bondvic@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Zavalniuk, V.V., E-mail: vzavalnyuk@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Department of Fundamental Sciences, Odessa Military Academy, 10 Fontanska Road, Odessa 65009 (Ukraine)

2016-11-11

Highlights: • The origin of sound-like dispersion of graphene bending mode is disclosed. • The speed of graphene bending sound is determined. • The renormalized graphene bending rigidity is derived. • The intrinsic corrugations of graphene are estimated. - Abstract: It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

Bending sound in graphene: Origin and manifestation

International Nuclear Information System (INIS)

Adamyan, V.M.; Bondarev, V.N.; Zavalniuk, V.V.

2016-01-01

Highlights: • The origin of sound-like dispersion of graphene bending mode is disclosed. • The speed of graphene bending sound is determined. • The renormalized graphene bending rigidity is derived. • The intrinsic corrugations of graphene are estimated. - Abstract: It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

Formulation of Forming Load in V-Bending

Directory of Open Access Journals (Sweden)

Koumura Yuki

2016-01-01

Full Text Available A novel method is described to calculate the forming load in V-bending by a press brake. The data of forming load are collected by FEM analysis. With an increase of the punch stroke in V-bending, the forming load increases gradually after the elastic limit, and then decreases after showing the maximum value. The proposal formulation to trace the variations in the forming load curve includes the calculating method of the load of the elastic limit, the maximum load in air bending and the variations of the forming load before/after the bending stroke of the maximum load. The calculated precision is confirmed by comparing with the measured load-stroke curves in V-bending with a press brake.

Numerical identification of secondary buckling phenomena of elastic rectangular plate under pure bending; Tomage wo ukeru dansei kukeiban ni shojiru niji zakutsu

Energy Technology Data Exchange (ETDEWEB)

Nakazawa, M.; Ikeda, K. [Tohoku University, Sendai (Japan). Faculty of Engineering; Wachi, S. [NKK Corp., Tokyo (Japan); Kuranishi, S. [Kanto Gakuin University, Yokohama (Japan)

1995-07-21

In this paper, the secondary buckling phenomena of the elastic rectangular plate subject to the pure bending moment are investigated. The bifurcation points are classified numerically based on the determinant of tangential stiffness matrix and of its diagonal blocks obtained by means of the group-theoretic bifurcation theory. By using the sub-matrices within the whole block-diagonalized one, the informations of the instability points and equilibrium paths after bifurcation are easily obtained. The quantitative influence of the initial imperfections are investigated based on the asymptotic laws and the Monte Carlo simulations. 30 refs., 12 figs., 1 tab.

Permanent bending and alignment of ZnO nanowires

Energy Technology Data Exchange (ETDEWEB)

Borschel, Christian; Spindler, Susann; Oertel, Michael; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Lerose, Damiana [MPI fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle/Saale (Germany); Institut fuer Photonische Technologien, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Bochmann, Arne [Institut fuer Photonische Technologien, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Christiansen, Silke H. [Institut fuer Photonische Technologien, Albert-Einstein-Strasse 9, 07745 Jena (Germany); MPI fuer die Physik des Lichts, Guenther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Nietzsche, Sandor [Zentrum fuer Elektronenmikroskopie, Friedrich-Schiller-Universitaet Jena, Ziegelmuehlenweg 1, 07743 Jena (Germany)

2011-07-01

Ion beams can be used to bend or re-align nanowires permanently, after they have been grown. We have irradiated ZnO nanowires with ions of different species and energy, achieving bending and alignment in various directions. We study the bending of single nanowires as well as the simultaneous alignment of large ensembles of ZnO nanowires in detail. Computer simulations show that the bending is initiated by ion beam induced damage. Dislocations are identified to relax stresses and make the bending and alignment permanent and resistant against annealing procedures.

Real-Time Vision-Based Stiffness Mapping †.

Science.gov (United States)

Faragasso, Angela; Bimbo, João; Stilli, Agostino; Wurdemann, Helge Arne; Althoefer, Kaspar; Asama, Hajime

2018-04-26

This paper presents new findings concerning a hand-held stiffness probe for the medical diagnosis of abnormalities during palpation of soft-tissue. Palpation is recognized by the medical community as an essential and low-cost method to detect and diagnose disease in soft-tissue. However, differences are often subtle and clinicians need to train for many years before they can conduct a reliable diagnosis. The probe presented here fills this gap providing a means to easily obtain stiffness values of soft tissue during a palpation procedure. Our stiffness sensor is equipped with a multi degree of freedom (DoF) Aurora magnetic tracker, allowing us to track and record the 3D position of the probe whilst examining a tissue area, and generate a 3D stiffness map in real-time. The stiffness probe was integrated in a robotic arm and tested in an artificial environment representing a good model of soft tissue organs; the results show that the sensor can accurately measure and map the stiffness of a silicon phantom embedded with areas of varying stiffness.

Real-Time Vision-Based Stiffness Mapping †

Directory of Open Access Journals (Sweden)

Angela Faragasso

2018-04-01

Full Text Available This paper presents new findings concerning a hand-held stiffness probe for the medical diagnosis of abnormalities during palpation of soft-tissue. Palpation is recognized by the medical community as an essential and low-cost method to detect and diagnose disease in soft-tissue. However, differences are often subtle and clinicians need to train for many years before they can conduct a reliable diagnosis. The probe presented here fills this gap providing a means to easily obtain stiffness values of soft tissue during a palpation procedure. Our stiffness sensor is equipped with a multi degree of freedom (DoF Aurora magnetic tracker, allowing us to track and record the 3D position of the probe whilst examining a tissue area, and generate a 3D stiffness map in real-time. The stiffness probe was integrated in a robotic arm and tested in an artificial environment representing a good model of soft tissue organs; the results show that the sensor can accurately measure and map the stiffness of a silicon phantom embedded with areas of varying stiffness.

Dynamic stiffness of suction caissons - vertical vibrations

Energy Technology Data Exchange (ETDEWEB)

Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

2006-12-15

The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

Assessment of a virtual functional prototyping process for the rapid manufacture of passive-dynamic ankle-foot orthoses.

Science.gov (United States)

Schrank, Elisa S; Hitch, Lester; Wallace, Kevin; Moore, Richard; Stanhope, Steven J

2013-10-01

Passive-dynamic ankle-foot orthosis (PD-AFO) bending stiffness is a key functional characteristic for achieving enhanced gait function. However, current orthosis customization methods inhibit objective premanufacture tuning of the PD-AFO bending stiffness, making optimization of orthosis function challenging. We have developed a novel virtual functional prototyping (VFP) process, which harnesses the strengths of computer aided design (CAD) model parameterization and finite element analysis, to quantitatively tune and predict the functional characteristics of a PD-AFO, which is rapidly manufactured via fused deposition modeling (FDM). The purpose of this study was to assess the VFP process for PD-AFO bending stiffness. A PD-AFO CAD model was customized for a healthy subject and tuned to four bending stiffness values via VFP. Two sets of each tuned model were fabricated via FDM using medical-grade polycarbonate (PC-ISO). Dimensional accuracy of the fabricated orthoses was excellent (average 0.51 ± 0.39 mm). Manufacturing precision ranged from 0.0 to 0.74 Nm/deg (average 0.30 ± 0.36 Nm/deg). Bending stiffness prediction accuracy was within 1 Nm/deg using the manufacturer provided PC-ISO elastic modulus (average 0.48 ± 0.35 Nm/deg). Using an experimentally derived PC-ISO elastic modulus improved the optimized bending stiffness prediction accuracy (average 0.29 ± 0.57 Nm/deg). Robustness of the derived modulus was tested by carrying out the VFP process for a disparate subject, tuning the PD-AFO model to five bending stiffness values. For this disparate subject, bending stiffness prediction accuracy was strong (average 0.20 ± 0.14 Nm/deg). Overall, the VFP process had excellent dimensional accuracy, good manufacturing precision, and strong prediction accuracy with the derived modulus. Implementing VFP as part of our PD-AFO customization and manufacturing framework, which also includes fit customization, provides a novel and powerful method to

Avaliação morfométrica de fibras nervosas do nervo ulnar após reparação cirúrgica com auto-enxerto e prótese tubular em cães

Directory of Open Access Journals (Sweden)

Ângelo João Stopiglia

1998-01-01

Full Text Available The purpose of this study was to evaluate, by morphometric analysis, the regenerated nerve fibers of dogs, after 26 weeks of observation, in gaps of the ulnar nerves substituted by allografts and tubular prosthesis of silicone. The ulnar nerves of four dogs were processed for electron microscopic evaluation. Six fields, with 1750 µm², for each dog and each procedure, were photographed at 1880x. A morphometric computer based analysis (Sigma Scan - Jandel Co., USA resulted in the following numbers (average numbers in micrometers. 1. ulnar nerve with tubular prosthesis- a: myelinated fiber diameter-5.12 ± 1.67. b: myelinated axon diameter: 4.08 ± 1.52. c: myelin sheath thickness-0.52 ± 0.18. d: unmyelinated axon diameter: 0.98 ± 0.37. 2. ulnar nerve with allograft- a: myelinated fiber diameter: 6.04 ± 2.27. b: myelinated axon diameter: 4.59 ± 1.95. c: myelin sheath thickness: 0.72 ± 0.23. d: unmyelinated axon diameter: 0.96 ± 0.40. The morphometric analysis after 26 weeks of nerve repair didn’t show a significant difference between the two surgical procedures.

Strength tests of thin-walled elliptic duralumin cylinders in pure bending and in combined pure bending and torsion

Science.gov (United States)

Lundquist, Eugene E; Stowell, Elbridge Z

1942-01-01

An analysis is presented of the results of tests made by the Massachusetts Institute of Technology and by the National Advisory Committee for Aeronautics on an investigation of the strength of thin-walled circular and elliptic cylinders in pure bending and in combined torsion and bending. In each of the loading conditions, the bending moments were applied in the plane of the major axis of the ellipse.

Bending characteristics of resin concretes

Directory of Open Access Journals (Sweden)

Ribeiro Maria Cristina Santos

2003-01-01

Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.

Observer-Based Human Knee Stiffness Estimation.

Science.gov (United States)

Misgeld, Berno J E; Luken, Markus; Riener, Robert; Leonhardt, Steffen

2017-05-01

We consider the problem of stiffness estimation for the human knee joint during motion in the sagittal plane. The new stiffness estimator uses a nonlinear reduced-order biomechanical model and a body sensor network (BSN). The developed model is based on a two-dimensional knee kinematics approach to calculate the angle-dependent lever arms and the torques of the muscle-tendon-complex. To minimize errors in the knee stiffness estimation procedure that result from model uncertainties, a nonlinear observer is developed. The observer uses the electromyogram (EMG) of involved muscles as input signals and the segmental orientation as the output signal to correct the observer-internal states. Because of dominating model nonlinearities and nonsmoothness of the corresponding nonlinear functions, an unscented Kalman filter is designed to compute and update the observer feedback (Kalman) gain matrix. The observer-based stiffness estimation algorithm is subsequently evaluated in simulations and in a test bench, specifically designed to provide robotic movement support for the human knee joint. In silico and experimental validation underline the good performance of the knee stiffness estimation even in the cases of a knee stiffening due to antagonistic coactivation. We have shown the principle function of an observer-based approach to knee stiffness estimation that employs EMG signals and segmental orientation provided by our own IPANEMA BSN. The presented approach makes realtime, model-based estimation of knee stiffness with minimal instrumentation possible.

Bending-Tolerant Anodes for Lithium-Metal Batteries.

Science.gov (United States)

Wang, Aoxuan; Tang, Shan; Kong, Debin; Liu, Shan; Chiou, Kevin; Zhi, Linjie; Huang, Jiaxing; Xia, Yong-Yao; Luo, Jiayan

2018-01-01

Bendable energy-storage systems with high energy density are demanded for conformal electronics. Lithium-metal batteries including lithium-sulfur and lithium-oxygen cells have much higher theoretical energy density than lithium-ion batteries. Reckoned as the ideal anode, however, Li has many challenges when directly used, especially its tendency to form dendrite. Under bending conditions, the Li-dendrite growth can be further aggravated due to bending-induced local plastic deformation and Li-filaments pulverization. Here, the Li-metal anodes are made bending tolerant by integrating Li into bendable scaffolds such as reduced graphene oxide (r-GO) films. In the composites, the bending stress is largely dissipated by the scaffolds. The scaffolds have increased available surface for homogeneous Li plating and minimize volume fluctuation of Li electrodes during cycling. Significantly improved cycling performance under bending conditions is achieved. With the bending-tolerant r-GO/Li-metal anode, bendable lithium-sulfur and lithium-oxygen batteries with long cycling stability are realized. A bendable integrated solar cell-battery system charged by light with stable output and a series connected bendable battery pack with higher voltage is also demonstrated. It is anticipated that this bending-tolerant anode can be combined with further electrolytes and cathodes to develop new bendable energy systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of a quasi-zero-stiffness isolator

International Nuclear Information System (INIS)

Carrella, A.; Brennan, M. J.; Waters, T. P.

2007-01-01

The frequency range over which a mount can isolate a mass from a vibrating base (or vice versa) is often limited by the mount stiffness required to support the weight of the mass. This compromise can be made more favourable by employing non-linear mounts with a softening spring characteristic such that small excursions about the static equilibrium position result in small dynamic spring forces and a correspondingly low natural frequency. This paper concerns the force-displacement characteristic of a so-called quasi-zero-stiffness (QZS) mechanism which is characterised by an appreciable static stiffness but very small (theoretically zero) dynamic stiffness. The mechanism studied comprises a vertical spring acting in parallel with two further springs which, when inclined at an appropriate angle to the vertical, produce a cancelling negative stiffness effect. Analysis of the system shows that a QZS characteristic can be obtained if the systems parameters (angle of inclination and ratio of spring stiffness) are opportunely chosen. By introducing the additional criterion that the displacement of the system be largest without exceeding a desired (low) value of stiffness an optimal set of parameter values is derived. Under sufficiently large displacements the stiffness of the QZS mechanism can eventually exceed that of the simple mass-spring system and criteria for this detrimental scenario to arise are presented

Flow patterns and hydraulic losses in quasi-coil pipes : The effects of configuration of bend cross section, curvature ratio and bend angle

OpenAIRE

Shimizu, Yukimaru; Sugino, Koichi; Yasui, Masaji; Hayakawa, Yukitaka; Kuzuhara, Sadao

1985-01-01

Pipes with bend combinations are much used in the heat exchangers, since the curved path in the bends promotes the mixing in flow for active heat transfer. In the present paper, one of the pipes with bend combinations, namely, quasi-coiled pipes composed of many bend elements are investigated, and the relationships between the hydraulic loss and the secondary flow are studied experimentally. The configurations of the cross sections, the bent angles and the curvature ratios of the bend element...

Performance of an anisotropic Allman/DKT 3-node thin triangular flat shell element

Science.gov (United States)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

1992-05-01

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular flat shell element in global coordinates is presented. An Allman triangle (AT) is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending element. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, the membrane and bending strain-displacement matrices. Using the aforementioned approach, the objective of this study is to develop and test the performance of a practical 3-node flat shell element that could be used in plate problems with unsymmetrically stacked composite laminates. The performance of the latter element is tested on plates of varying aspect ratios. The developed 3-node shell element should simplify the programming task and have the potential of reducing the computational time.

Symmetric bends how to join two lengths of cord

CERN Document Server

Miles, Roger E

1995-01-01

A bend is a knot securely joining together two lengths of cord (or string or rope), thereby yielding a single longer length. There are many possible different bends, and a natural question that has probably occurred to many is: "Is there a 'best' bend and, if so, what is it?"Most of the well-known bends happen to be symmetric - that is, the two constituent cords within the bend have the same geometric shape and size, and interrelationship with the other. Such 'symmetric bends' have great beauty, especially when the two cords bear different colours. Moreover, they have the practical advantage o

Tunable waveguide bends with graphene-based anisotropic metamaterials

KAUST Repository

Chen, Zhao-xian; Chen, Ze-guo; Ming, Yang; Wu, Ying; Lu, Yan-qing

2016-01-01

We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.

Tunable waveguide bends with graphene-based anisotropic metamaterials

KAUST Repository

Chen, Zhao-xian

2016-01-15

We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.

Anterior subcutaneous transposition of the ulnar nerve improves neurological function in patients with cubital tunnel syndrome

Directory of Open Access Journals (Sweden)

Wei Huang

2015-01-01

Full Text Available Although several surgical procedures exist for treating cubital tunnel syndrome, the best surgical option remains controversial. To evaluate the efficacy of anterior subcutaneous transposition of the ulnar nerve in patients with moderate to severe cubital tunnel syndrome and to analyze prognostic factors, we retrospectively reviewed 62 patients (65 elbows diagnosed with cubital tunnel syndrome who underwent anterior subcutaneous transposition. Preoperatively, the initial severity of the disease was evaluated using the McGowan scale as modified by Goldberg: 18 patients (28% had grade IIA neuropathy, 20 (31% had grade IIB, and 27 (42% had grade III. Postoperatively, according to the Wilson & Krout criteria, treatment outcomes were excellent in 38 patients (58%, good in 16 (25%, fair in 7 (11%, and poor in 4 (6%, with an excellent and good rate of 83%. A negative correlation was found between the preoperative McGowan grade and the postoperative Wilson & Krout score. The patients having fair and poor treatment outcomes had more advanced age, lower nerve conduction velocity, and lower action potential amplitude compared with those having excellent and good treatment outcomes. These results suggest that anterior subcutaneous transposition of the ulnar nerve is effective and safe for the treatment of moderate to severe cubital tunnel syndrome, and initial severity, advancing age, and electrophysiological parameters can affect treatment outcome.

Effects of laser bending on the microstructural constituents

CSIR Research Space (South Africa)

Tshabalala, L

2012-01-01

Full Text Available This article will illustrate the correlation between microstructural and microhardness changes in high-strength-low-alloy steel that occur as a result of laser-bending. Laser bending is a process of bending metal shapes using the laser beam...

Constitutive Modelling of Resins in the Stiffness Domain

Science.gov (United States)

Klasztorny, M.

2004-09-01

An analytic method for inverting the constitutive compliance equations of viscoelasticity for resins is developed. These equations describe the HWKK/H rheological model, which makes it possible to simulate, with a good accuracy, short-, medium- and long-term viscoelastic processes in epoxy and polyester resins. These processes are of first-rank reversible isothermal type. The time histories of deviatoric stresses are simulated with three independent strain history functions of fractional and normal exponential types. The stiffness equations are described by two elastic and six viscoelastic constants having a clear physic meaning (three long-term relaxation coefficients and three relaxation times). The time histories of axiatoric stresses are simulated as perfectly elastic. The inversion method utilizes approximate constitutive stiffness equations of viscoelasticity for the HWKK/H model. The constitutive compliance equations for the model are a basis for determining the exact complex shear stiffness, whereas the approximate constitutive stiffness equations are used for determining the approximate complex shear stiffness. The viscoelastic constants in the stiffness domain are derived by equating the exact and approximate complex shear stiffnesses. The viscoelastic constants are obtained for Epidian 53 epoxy and Polimal 109 polyester resins. The accuracy of the approximate constitutive stiffness equations are assessed by comparing the approximate and exact complex shear stiffnesses. The constitutive stiffness equations for the HWKK/H model are presented in uncoupled (shear/bulk) and coupled forms. Formulae for converting the constants of shear viscoelasticity into the constants of coupled viscoelasticity are given as well.

Electrostatic bending response of a charged helix

Science.gov (United States)

Zampetaki, A. V.; Stockhofe, J.; Schmelcher, P.

2018-04-01

We explore the electrostatic bending response of a chain of charged particles confined on a finite helical filament. We analyze how the energy difference Δ E between the bent and the unbent helical chain scales with the length of the helical segment and the radius of curvature and identify features that are not captured by the standard notion of the bending rigidity, normally used as a measure of bending tendency in the linear response regime. Using Δ E to characterize the bending response of the helical chain we identify two regimes with qualitatively different bending behaviors for the ground state configuration: the regime of small and the regime of large radius-to-pitch ratio, respectively. Within the former regime, Δ E changes smoothly with the variation of the system parameters. Of particular interest are its oscillations with the number of charged particles encountered for commensurate fillings which yield length-dependent oscillations in the preferred bending direction of the helical chain. We show that the origin of these oscillations is the nonuniformity of the charge distribution caused by the long-range character of the Coulomb interactions and the finite length of the helix. In the second regime of large values of the radius-to-pitch ratio, sudden changes in the ground state structure of the charges occur as the system parameters vary, leading to complex and discontinuous variations in the ground state bending response Δ E .

Effects of tanalith-e impregnation substance on bending strengths and modulus of elasticity in bending of some wood types

Directory of Open Access Journals (Sweden)

Hakan Keskin

2016-04-01

Full Text Available The aim of this study was to investigate the effects of impregnation with Tanalith-E on the bending strengths and modulus of elasticity in bending of some wood types. The test samples prepared from beech, oak, walnut, poplar, ash and pine wood materials - that are of common use in the forest products industry of TURKEY - according to TS 345, were treated with according to ASTM D 1413-76 substantially. Un-impregnated samples according to impregnated wood materials, the bending strengths in beech to 6.83%, 5.12% in ash, 5.93% in pine, the elasticity module values to 7.15% in oak and ash, at a rate of 6.58% in the higher were found. The highest values of bending strengths and modulus of elasticity in bending were obtained in beech and ash woods impregnated with Tanalith-E, whereas the lowest values were obtained in the poplar wood.

Influence of Hamstring Tightness in Pelvic, Lumbar and Trunk Range of Motion in Low Back Pain and Asymptomatic Volunteers during Forward Bending.

Science.gov (United States)

Jandre Reis, Felipe Jose; Macedo, Adriana Ribeiro

2015-08-01

Cross-sectional study. To verify the association of hamstring tightness and range of motion in anterior pelvic tilt (PT), lumbar motion (LM), and trunk flexion (TF) during forward bending. Increased hamstring stiffness could be a possible contributing factor to low back injuries. Clinical observations have suggested that hamstring tightness influences lumbar pelvic rhythm. Movement restrictions or postural asymmetry likely lead to compensatory movement patterns of the lumbar spine, and subsequently to increased stress on the spinal soft tissues and an increased risk of low back pain (LBP). Hamstring muscle tightness was measured using the self-monitored active knee extension (AKE) test. A bubble inclinometer was used to determine the range of motion of PT, LM, and TF during forward bending. Statistical analysis included descriptive statistics, comparisons between groups and a correlation between hamstring tightness (AKE) and anterior PT, TF, and regional LM with p≤0.05. The LBP group was composed of 36 participants, and the asymptomatic group consisted of 32 participants. The mean for PT in the control group was 66.7°, 64.5° for LM and 104.6° for TF. Respective values in the symptomatic group were 57.0°, 79.8°, and 82.2°. Participants with LBP showed restriction in the pelvis and TF range of motion, but had higher amplitudes in the lumbar spine during forward bending.

The stiffness change and the increase in the ultimate capacity for a stiff pile resulting from a cyclic loading

DEFF Research Database (Denmark)

Lada, Aleksandra; Ibsen, Lars Bo; Nicolai, Giulio

In the paper the experimental results of small-scale tests on a stiff monopile are presented to outline the change in stiffness during the cyclic loading and the change in the ultimate pile capacity. The results confirm the increase of stiffness and the increase in bearing capacity resulting from...

Study of the Carrier-Aided Thin Film Electrode Array Design for Cochlear Insertion

Directory of Open Access Journals (Sweden)

Yuchen Xu

2018-04-01

Full Text Available The micro-fabricated thin film electrode array (TFEA has been a promising design for cochlear implants (CIs because of its cost-effectiveness and fabrication precision. The latest polymer-based cochlear TFEAs have faced difficulties for cochlear insertion due to the lack of structural stiffness. To stiffen the TFEA, dissolvable stiffening materials, TFEAs with different structures, and TFEAs with commercial CIs as carriers have been invested. In this work, the concept of enhancing a Parylene TFEA with Kapton tape as a simpler carrier for cochlear insertion has been proved to be feasible. The bending stiffness of the Kapton-aided TFEA was characterized with an analytical model, a finite element model, and a cantilever bending experiment, respectively. While the Kapton tape increased the bending stiffness of the Parylene TFEA by 103 times, the 6-μm-thick TFEA with a similar Young’s modulus, as a polyimide, in turn significantly increased the bending stiffness of the 170-μm-thick Kapton carrier by 60%. This result indicated that even the TFEA is ultra-flexible and that its bending stiffness should not be neglected in the design or selection of its carrier.

Analytical study of a quasi-zero stiffness coupling using a torsion magnetic spring with negative stiffness

Science.gov (United States)

Zheng, Yisheng; Zhang, Xinong; Luo, Yajun; Zhang, Yahong; Xie, Shilin

2018-02-01

By now, many translation quasi-zero stiffness (QZS) mechanisms have been proposed to overcome the restriction between the isolation frequency range and the load bearing capacity of linear isolators. The couplings of rotor systems undertake the functions of transmitting static driving torque and isolating disturbing torque simultaneously, which creates the demand of torsion QZS mechanisms. Hence a QZS coupling is presented in this paper, where a torsion magnetic spring (TMS) composed of two coaxial ring magnet arrangements in repulsive configuration is employed to produce negative torsion stiffness to counteract the positive stiffness of a rubber spring. In this paper, the expressions of magnetic torque and stiffness are given firstly and verified by finite element simulations; and the effect of geometric parameters of the TMS on its stiffness characteristic is analyzed in detail, which contributes to the optimal design of the TMS. Then dynamic analysis of the QZS coupling is performed and the analytical expression of the torque transmissibility is achieved based on the Harmonic Balance Method. Finally, simulation of the torque transmissibility is carried out to reveal how geometric parameters of the TMS affect the isolation performance.

Standard test methods for bend testing of material for ductility

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 These test methods cover bend testing for ductility of materials. Included in the procedures are four conditions of constraint on the bent portion of the specimen; a guided-bend test using a mandrel or plunger of defined dimensions to force the mid-length of the specimen between two supports separated by a defined space; a semi-guided bend test in which the specimen is bent, while in contact with a mandrel, through a specified angle or to a specified inside radius (r) of curvature, measured while under the bending force; a free-bend test in which the ends of the specimen are brought toward each other, but in which no transverse force is applied to the bend itself and there is no contact of the concave inside surface of the bend with other material; a bend and flatten test, in which a transverse force is applied to the bend such that the legs make contact with each other over the length of the specimen. 1.2 After bending, the convex surface of the bend is examined for evidence of a crack or surface irregu...

Metal-bending brake facilitates lightweight, close-tolerance fabrication

Science.gov (United States)

Ercoline, A. L.; Wilton, K. B.

1964-01-01

A lightweight, metal bending brake ensures very accurate bends. Features of the brake that adapt it for making complex reverse bends to close tolerances are a pronounced relief or cutaway of the underside of the bodyplate combined with modification in the leaf design and its suspension.

Stiffness of Railway Soil-Steel Structures

Directory of Open Access Journals (Sweden)

Machelski Czesław

2015-12-01

Full Text Available The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces, as in bridges. The analyzed cases show that the shell’s span, geometry (static scheme and the height of earth fill influence the stiffness of the structure. The soil-steel structure’s characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

Stiffness of Railway Soil-Steel Structures

Science.gov (United States)

Machelski, Czesław

2015-12-01

The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness) become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces), as in bridges. The analyzed cases show that the shell's span, geometry (static scheme) and the height of earth fill influence the stiffness of the structure. The soil-steel structure's characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

Neurophysiological localisation of ulnar neuropathy at the elbow: validation of diagnostic criteria developed by a taskforce of the Danish Society of Clinical Neurophysiology

DEFF Research Database (Denmark)

Pugdahl, Kirsten; Beniczky, Sándor; Wanscher, Benedikte

2017-01-01

OBJECTIVE: This study validates consensus criteria for localisation of ulnar neuropathy at elbow (UNE) developed by a taskforce of the Danish Society of Clinical Neurophysiology and compares them to the existing criteria from the American Association of Neuromuscular and Electrodiagnostic Medicine...

Load tests with a pipe bend DN 425, applying slowly changing bending loads up to occurrence of leak

International Nuclear Information System (INIS)

Uhlmann, D.; Hunger, H.

1990-01-01

The experimental program deals with the formation of incipient cracks and subsequent crack growth of axially oriented cracks at a pipe bend with a nominal width of DN 425. The pipe bend consists of the ferritic material 20MnMoNi55. The numerical experiments by means of 3 D-FE analyses concentrate on determining the influence of the asymmetric crack depths at the two bend halves, and of the multiple crack fields, on the effective crack strain. (DG) [de

Single motor–variable stiffness actuator using bistable switching mechanisms for independent motion and stiffness control

NARCIS (Netherlands)

Groothuis, Stefan; Carloni, Raffaella; Stramigioli, Stefano

This paper presents a proof of concept of a variable stiffness actuator (VSA) that uses only one (high power) input motor. In general, VSAs use two (high power) motors to be able to control both the output position and the output stiffness, which possibly results in a heavy, and bulky system. In

Mechanical behaviour of bending bucky-gel actuators and its representation

International Nuclear Information System (INIS)

Kruusamäe, Karl; Mukai, Ken; Sugino, Takushi; Asaka, Kinji

2014-01-01

Bucky-gel actuators are ionic electromechanically active materials that bend in response to a low-voltage excitation. While bending actuators may offer new approaches in engineering solutions, the characterization of bending poses many challenges in comparison to conventional rotary motion. It is often desired to reduce the bending behaviour to a single parameter, which may lead to the loss of accuracy in modelling. A high-speed laser profilometer is utilized to characterize the bending response of different bucky-gel actuators at their full length and to critically compare the applicability of existing representation tools for bending. The best analytical representation of the bending of a bucky-gel actuator is found to be in the form of a power function. It is also observed that, along the length of the actuator, sections closer to the electrical input clamp exhibit back-relaxation (a common drawback for bending ionic actuators) already when the far end of the bending strip is still in forward motion. (paper)

Big bang nucleosynthesis with a stiff fluid

International Nuclear Information System (INIS)

Dutta, Sourish; Scherrer, Robert J.

2010-01-01

Models that lead to a cosmological stiff fluid component, with a density ρ S that scales as a -6 , where a is the scale factor, have been proposed recently in a variety of contexts. We calculate numerically the effect of such a stiff fluid on the primordial element abundances. Because the stiff fluid energy density decreases with the scale factor more rapidly than radiation, it produces a relatively larger change in the primordial helium-4 abundance than in the other element abundances, relative to the changes produced by an additional radiation component. We show that the helium-4 abundance varies linearly with the density of the stiff fluid at a fixed fiducial temperature. Taking ρ S10 and ρ R10 to be the stiff fluid energy density and the standard density in relativistic particles, respectively, at T=10 MeV, we find that the change in the primordial helium abundance is well-fit by ΔY p =0.00024(ρ S10 /ρ R10 ). The changes in the helium-4 abundance produced by additional radiation or by a stiff fluid are identical when these two components have equal density at a 'pivot temperature', T * , where we find T * =0.55 MeV. Current estimates of the primordial 4 He abundance give the constraint on a stiff fluid energy density of ρ S10 /ρ R10 <30.

Direct measurement of the intrinsic ankle stiffness during standing.

Science.gov (United States)

Vlutters, M; Boonstra, T A; Schouten, A C; van der Kooij, H

2015-05-01

Ankle stiffness contributes to standing balance, counteracting the destabilizing effect of gravity. The ankle stiffness together with the compliance between the foot and the support surface make up the ankle-foot stiffness, which is relevant to quiet standing. The contribution of the intrinsic ankle-foot stiffness to balance, and the ankle-foot stiffness amplitude dependency remain a topic of debate in the literature. We therefore developed an experimental protocol to directly measure the bilateral intrinsic ankle-foot stiffness during standing balance, and determine its amplitude dependency. By applying fast (40 ms) ramp-and-hold support surface rotations (0.005-0.08 rad) during standing, reflexive contributions could be excluded, and the amplitude dependency of the intrinsic ankle-foot stiffness was investigated. Results showed that reflexive activity could not have biased the torque used for estimating the intrinsic stiffness. Furthermore, subjects required less recovery action to restore balance after bilateral rotations in opposite directions compared to rotations in the same direction. The intrinsic ankle-foot stiffness appears insufficient to ensure balance, ranging from 0.93±0.09 to 0.44±0.06 (normalized to critical stiffness 'mgh'). This implies that changes in muscle activation are required to maintain balance. The non-linear stiffness decrease with increasing rotation amplitude supports the previous published research. With the proposed method reflexive effects can be ruled out from the measured torque without any model assumptions, allowing direct estimation of intrinsic stiffness during standing. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Influence of Shaft’s Bending on the Coupling Vibration of a Flexible Blade-Rotor System

Directory of Open Access Journals (Sweden)

Chao-feng Li

2017-01-01

Full Text Available The influence of shaft bending on the coupling vibration of rotor-blades system is nonignorable. Therefore, this paper analyzed the influence of shaft bending on the coupling vibration of rotor-blades system. The vibration mode function of shaft under elastic supporting condition was also derived to ensure accuracy of the model as well. The influence of the number of blades, the position of disk, and the support stiffness of shaft on critical speed of system was analyzed. The numerical results show that there were two categories of coupling mode shapes which belong to a set where the blade’s first two modes predominate in the system: shaft-blade (SB mode and interblade (BB mode due to the coupling between blade and shaft. The BB mode was of repeated frequencies of (Nb-2 multiplicity for number blades, and the SB mode was of repeated frequencies of (2 multiplicity for number blades. What is more, with the increase of the number of blades, natural frequency of rotor was decreasing linearly, that of BB mode was constant, and that of SB mode was increasing linearly. Natural frequency of BB mode was not affected while that of rotor and SB mode was affected (changed symmetrically with the center of shaft by the position of disk. In the end, vibration characteristics of coupling mode shapes were analyzed.

Preliminary Analysis of the Fuel Bundle Stiffness by ANSYS for SFR

Energy Technology Data Exchange (ETDEWEB)

Lee, Byoung Oon; Cheon, Jin Sik; Hahn, Do Hee; Lee, Chan Bock [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2008-05-15

In SFR (Sodium-cooled Fast Reactor) the temperature of the fuel pin is higher than that of the hexagonal duct, so the thermal expansion rate of the fuel bundle is higher than that of the duct. The neutron fluence and the fuel pin pressure are also increased according to the burnup. So the radial expansion and bowing of a fuel pin bundle would occur, and then fuel bundle would interact with a duct. This phenomenon is called bundle-to-duct interaction (BDI). Under the BDI condition, excess cladding strain and hot spots would occur. Therefore BDI as well as the core mechanics should be considered to evaluate the FBR fuel integrity. The analysis codes such as ETOILE, SHADOW, and MARSE, have been developed to evaluate the BDI behavior. The ANSYS based model is also being developed to analysis the bundle duct interaction for SFR in Korea. In this paper, the fuel pin/bundle model for analyzing the bending deflection and oval deformation was described. The preliminary analysis of the fuel bundle stiffness was performed by the developed model.

High-sensitivity bend angle measurements using optical fiber gratings.

Science.gov (United States)

Rauf, Abdul; Zhao, Jianlin; Jiang, Biqiang

2013-07-20

We present a high-sensitivity and more flexible bend measurement method, which is based on the coupling of core mode to the cladding modes at the bending region in concatenation with optical fiber grating serving as band reflector. The characteristics of a bend sensing arm composed of bending region and optical fiber grating is examined for different configurations including single fiber Bragg grating (FBG), chirped FBG (CFBG), and double FBGs. The bend loss curves for coated, stripped, and etched sections of fiber in the bending region with FBG, CFBG, and double FBG are obtained experimentally. The effect of separation between bending region and optical fiber grating on loss is measured. The loss responses for single FBG and CFBG configurations are compared to discover the effectiveness for practical applications. It is demonstrated that the sensitivity of the double FBG scheme is twice that of the single FBG and CFBG configurations, and hence acts as sensitivity multiplier. The bend loss response for different fiber diameters obtained through etching in 40% hydrofluoric acid, is measured in double FBG scheme that resulted in a significant increase in the sensitivity, and reduction of dead-zone.

Observed variations of monopile foundation stiffness

DEFF Research Database (Denmark)

Kallehave, Dan; Thilsted, C.L.; Diaz, Alberto Troya

2015-01-01

full-scale measurements obtained from one offshore wind turbine structure located within Horns Reef II offshore wind farm. Data are presented for a 2.5 years period and covers normal operating conditions and one larger storm event. A reduction of the pile-soil stiffness was observed during the storm...... events, followed by a complete regain to a pre-storm level when the storm subsided. In additional, no long term variations of the pile-soil stiffness was observed. The wind turbine is located in dense to very dense sand deposits.......The soil-structure stiffness of monopile foundations for offshore wind turbines has a high impact on the fatigue loading during normal operating conditions. Thus, a robust design must consider the evolution of pile-soil stiffness over the lifetime of the wind farm. This paper present and discuss...

Stiff Hands

Science.gov (United States)

... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy Stiff Hands Email to a friend * required fields ...

A Stewart isolator with high-static-low-dynamic stiffness struts based on negative stiffness magnetic springs

Science.gov (United States)

Zheng, Yisheng; Li, Qingpin; Yan, Bo; Luo, Yajun; Zhang, Xinong

2018-05-01

In order to improve the isolation performance of passive Stewart platforms, the negative stiffness magnetic spring (NSMS) is employed to construct high static low dynamic stiffness (HSLDS) struts. With the NSMS, the resonance frequencies of the platform can be reduced effectively without deteriorating its load bearing capacity. The model of the Stewart isolation platform with HSLDS struts is presented and the stiffness characteristic of its struts is studied firstly. Then the nonlinear dynamic model of the platform including both geometry nonlinearity and stiffness nonlinearity is established; and its simplified dynamic model is derived under the condition of small vibration. The effect of nonlinearity on the isolation performance is also evaluated. Finally, a prototype is built and the isolation performance is tested. Both simulated and experimental results demonstrate that, by using the NSMS, the resonance frequencies of the Stewart isolator are reduced and the isolation performance in all six directions is improved: the isolation frequency band is increased and extended to a lower-frequency level.

Accounting for Fiber Bending Effects in Homogenization of Long Fiber Reinforced Composites

DEFF Research Database (Denmark)

Poulios, Konstantinos; Niordson, Christian Frithiof

2015-01-01

The present work deals with homogenized finite-element models of long fiber reinforced composite materials in the context of studying compressive failure modes such as the formation of kink bands and fiber micro-buckling. Compared to finite-element models with an explicit discretization of the ma......The present work deals with homogenized finite-element models of long fiber reinforced composite materials in the context of studying compressive failure modes such as the formation of kink bands and fiber micro-buckling. Compared to finite-element models with an explicit discretization...... of the material micro-structure including individual fibers, homogenized models are computationally more efficient and hence more suitable for modeling of larger and complex structure. Nevertheless, the formulation of homogenized models is more complicated, especially if the bending stiffness of the reinforcing...... fibers is to be taken into account. In that case, so-called higher order strain terms need to be considered. In this paper, important relevant works from the literature are discussed and numerical results from a new homogenization model are presented. The new model accounts for two independent...

MRI shows thickening and altered diffusion in the median and ulnar nerves in multifocal motor neuropathy

Energy Technology Data Exchange (ETDEWEB)

Haakma, Wieke [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Aarhus University, Department of Forensic Medicine and Comparative Medicine Lab, Aarhus (Denmark); Jongbloed, Bas A.; Goedee, H.S.; Berg, Leonard H. van den; Pol, W.L. van der [University Medical Center Utrecht, Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, Utrecht (Netherlands); Froeling, Martijn; Bos, Clemens; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Leemans, Alexander [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

2017-05-15

To study disease mechanisms in multifocal motor neuropathy (MMN) with magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) of the median and ulnar nerves. We enrolled ten MMN patients, ten patients with amyotrophic lateral sclerosis (ALS) and ten healthy controls (HCs). Patients underwent MRI (in a prone position) and nerve conduction studies. DTI and fat-suppressed T2-weighted scans of the forearms were performed on a 3.0T MRI scanner. Fibre tractography of the median and ulnar nerves was performed to extract diffusion parameters: fractional anisotropy (FA), mean (MD), axial (AD) and radial (RD) diffusivity. Cross-sectional areas (CSA) were measured on T2-weighted scans. Forty-five out of 60 arms were included in the analysis. AD was significantly lower in MMN patients (2.20 ± 0.12 x 10{sup -3} mm{sup 2}/s) compared to ALS patients (2.31 ± 0.17 x 10{sup -3} mm{sup 2}/s; p < 0.05) and HCs (2.31± 0.17 x 10{sup -3} mm{sup 2}/s; p < 0.05). Segmental analysis showed significant restriction of AD, RD and MD (p < 0.005) in the proximal third of the nerves. CSA was significantly larger in MMN patients compared to ALS patients and HCs (p < 0.01). Thickening of nerves is compatible with changes in the myelin sheath structure, whereas lowered AD values suggest axonal dysfunction. These findings suggest that myelin and axons are diffusely involved in MMN pathogenesis. (orig.)

AFM stiffness nanotomography of normal, metaplastic and dysplastic human esophageal cells

International Nuclear Information System (INIS)

Fuhrmann, A; Staunton, J R; Banyai, N; Davies, P C W; Ros, R; Nandakumar, V

2011-01-01

The mechanical stiffness of individual cells is important in tissue homeostasis, cell growth, division and motility, and the epithelial–mesenchymal transition in the initiation of cancer. In this work, a normal squamous cell line (EPC2) and metaplastic (CP-A) as well as dysplastic (CP-D) Barrett's Esophagus columnar cell lines are studied as a model of pre-neoplastic progression in the human esophagus. We used the combination of an atomic force microscope (AFM) with a scanning confocal fluorescence lifetime imaging microscope to study the mechanical properties of single adherent cells. Sixty four force indentation curves were taken over the nucleus of each cell in an 8 × 8 grid pattern. Analyzing the force indentation curves, indentation depth-dependent Young's moduli were found for all cell lines. Stiffness tomograms demonstrate distinct differences between the mechanical properties of the studied cell lines. Comparing the stiffness for indentation forces of 1 nN, most probable Young's moduli were calculated to 4.7 kPa for EPC2 (n = 18 cells), 3.1 kPa for CP-A (n = 10) and 2.6 kPa for CP-D (n = 19). We also tested the influence of nuclei and nucleoli staining organic dyes on the mechanical properties of the cells. For stained EPC2 cells (n = 5), significant stiffening was found (9.9 kPa), while CP-A cells (n = 5) showed no clear trend (2.9 kPa) and a slight softening was observed (2.1 kPa) in the case of CP-D cells (n = 16). Some force–indentation curves show non-monotonic discontinuities with segments of negative slope, resembling a sawtooth pattern. We found the incidence of these 'breakthrough events' to be highest in the dysplastic CP-D cells, intermediate in the metaplastic CP-A cells and lowest in the normal EPC2 cells. This observation suggests that the microscopic explanation for the increased compliance of cancerous and pre-cancerous cells may lie in their susceptibility to 'crumble and yield' rather than their

A novel energy-efficient rotational variable stiffness actuator

NARCIS (Netherlands)

Rao, S.; Carloni, Raffaella; Stramigioli, Stefano

This paper presents the working principle, the design and realization of a novel rotational variable stiffness actuator, whose stiffness can be varied independently of its output angular position. This actuator is energy-efficient, meaning that the stiffness of the actuator can be varied by keeping

A bend thickness sensitivity study of Candu feeder piping

International Nuclear Information System (INIS)

Li, M.; Aggarwal, M.L.; Meysner, A.; Micelotta, C.

2005-01-01

In CANDU reactors, feeder bends close to the connection at the fuel channel may be subjected to the highest Flow Accelerated Corrosion (FAC) and stresses. Feeder pipe stress analysis is crucial in the life extension of aging CANDU plants. Typical feeder pipes are interconnected by upper link plates and spacers. It is well known that the stresses at the bends are sensitive to the local bend thicknesses. It is also known from the authors' study (Li and et al, 2005) that feeder inter linkage effect is significant and cannot be ignored. The field measurement of feeder bend thickness is difficult and may be subjected to uncertainty in accuracy. Hence, it is desirable to know how the stress on a subject feeder could be affected by the bend thickness variation of the neighboring feeders. This effect cannot be evaluated by the traditional 'single' feeder model approach. In this paper, the 'row' and 'combined' models developed in the previous study (Li and et al, 2005), which include the feeder interactions, are used to investigate the sensitivity of bend thickness. A series of random thickness bounded by maximum and minimum measured values were applied to feeders in the model. The results show that an individual feeder is not sensitive to the bend thickness variation of the remaining feeders in the model, but depends primarily on its own bend thickness. The highest stress at a feeder always occurs when the feeder has the smallest possible bend thickness. A minimum acceptable bend thickness for individual feeders can be computed by an iterative computing process. The dependency of field thickness measurement and the amount of required analysis work can be greatly reduced. (authors)

A preliminary bending fatigue spectrum for steel monostrand cables

DEFF Research Database (Denmark)

Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.

2011-01-01

This paper presents the results of the experimental study on the bending fatigue resistance of high-strength steel monostrand cables. From the conducted fatigue tests in the high-stress, low-cycle region, a preliminary bending fatigue spectrum is derived for the estimation of monostrand cable...... service life expectancy. The presented preliminary bending fatigue spectrum of high-strength monostrands is currently unavailable in the published literature. The presented results provide relevant information on the bending mechanism and fatigue characteristics of monostrand steel cables in tension...... and flexure and show that localized cable bending has a pronounced influence on the fatigue resistance of cables under dynamic excitations....

Stiffness and the automatic selection of ODE codes

International Nuclear Information System (INIS)

Shampine, L.F.

1984-01-01

The author describes the basic ideas behind the most popular methods for the numerical solution of ordinary differential equations (ODEs). He takes up the qualitative behavior of solutions of ODEs and its relation ot the propagation of numerical error. Codes for ODEs are intended either for stiff problems or for non-stiff problems. The difference is explained. Users of codes do not have the information needed to recognize stiffness. A code, DEASY, which automatically recognizes stiffness and selects a suitable method is described

An experiment for determining the Euler load by direct computation

Science.gov (United States)

Thurston, Gaylen A.; Stein, Peter A.

1986-01-01

A direct algorithm is presented for computing the Euler load of a column from experimental data. The method is based on exact inextensional theory for imperfect columns, which predicts two distinct deflected shapes at loads near the Euler load. The bending stiffness of the column appears in the expression for the Euler load along with the column length, therefore the experimental data allows a direct computation of bending stiffness. Experiments on graphite-epoxy columns of rectangular cross-section are reported in the paper. The bending stiffness of each composite column computed from experiment is compared with predictions from laminated plate theory.

Morphological properties of the last primaries, the tail feathers, and the alulae of Accipiter nisus, Columba livia, Falco peregrinus, and Falco tinnunculus.

Science.gov (United States)

Schmitz, Anke; Ponitz, Benjamin; Brücker, Christoph; Schmitz, Helmut; Herweg, Jan; Bleckmann, Horst

2015-01-01

We investigated the mechanical properties (Young's modulus, bending stiffness, barb separation forces) of the tenth primary of the wings, of the alulae and of the middle tail feathers of Falco peregrinus. For comparison, we also investigated the corresponding feathers in pigeons (Columba livia), kestrels (Falco tinnunculus), and sparrowhawks (Accipiter nisus). In all four species, the Young's moduli of the feathers ranged from 5.9 to 8.4 GPa. The feather shafts of F. peregrinus had the largest cross-sections and the highest specific bending stiffness. When normalized with respect to body mass, the specific bending stiffness of primary number 10 was highest in F. tinnunculus, while that of the alula was highest in A. nisus. In comparison, the specific bending stiffness, measured at the base of the tail feathers and in dorso-ventral bending direction, was much higher in F. peregrinus than in the other three species. This seems to correlate with the flight styles of the birds: F. tinnunculus hovers and its primaries might therefore withstand large mechanical forces. A. nisus has often to change its flight directions during hunting and perhaps needs its alulae for this maneuvers, and in F. peregrinus, the base of the tail feathers might need a high stiffness during breaking after diving. © 2014 Wiley Periodicals, Inc.

Multi-fingered haptic palpation utilizing granular jamming stiffness feedback actuators

International Nuclear Information System (INIS)

Li, Min; Sareh, Sina; Seneviratne, Lakmal D; Wurdemann, Helge A; Althoefer, Kaspar; Ranzani, Tommaso; Dasgupta, Prokar

2014-01-01

This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and in robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback. (paper)

Effect of Ovality in Inlet Pigtail Pipe Bends Under Combined Internal Pressure and In-Plane Bending for Ni-Fe-Cr B407 Material

Directory of Open Access Journals (Sweden)

Ramaswami P.

2017-09-01

Full Text Available The present paper makes an attempt to depict the effect of ovality in the inlet pigtail pipe bend of a reformer under combined internal pressure and in-plane bending. Finite element analysis (FEA and experiments have been used. An incoloy Ni-Fe-Cr B407 alloy material was considered for study and assumed to be elastic-perfectly plastic in behavior. The design of pipe bend is based on ASME B31.3 standard and during manufacturing process, it is challenging to avoid thickening on the inner radius and thinning on the outer radius of pipe bend. This geometrical shape imperfection is known as ovality and its effect needs investigation which is considered for the study. The finite element analysis (ANSYS-workbench results showed that ovality affects the load carrying capacity of the pipe bend and it was varying with bend factor (h. By data fitting of finite element results, an empirical formula for the limit load of inlet pigtail pipe bend with ovality has been proposed, which is validated by experiments.

Ankle-foot orthosis bending axis influences running mechanics.

Science.gov (United States)

Russell Esposito, Elizabeth; Ranz, Ellyn C; Schmidtbauer, Kelly A; Neptune, Richard R; Wilken, Jason M

2017-07-01

Passive-dynamic ankle-foot orthoses (AFOs) are commonly prescribed to improve locomotion for people with lower limb musculoskeletal weakness. The clinical prescription and design process are typically qualitative and based on observational assessment and experience. Prior work examining the effect of AFO design characteristics generally excludes higher impact activities such as running, providing clinicians and researchers limited information to guide the development of objective prescription guidelines. The proximal location of the bending axis may directly influence energy storage and return and resulting running mechanics. The purpose of this study was to determine if the location of an AFO's bending axis influences running mechanics. Marker and force data were recorded as 12 participants with lower extremity weakness ran overground while wearing a passive-dynamic AFO with posterior struts manufactured with central (middle) and off-centered (high and low) bending axes. Lower extremity joint angles, moments, powers, and ground reaction forces were calculated and compared between limbs and across bending axis conditions. Bending axis produced relatively small but significant changes. Ankle range of motion increased as the bending axis shifted distally (pbenefits during running, although individual preference and physical ability should also be considered. Published by Elsevier B.V.

Bending and tensile deformation of metallic nanowires

International Nuclear Information System (INIS)

McDowell, Matthew T; Leach, Austin M; Gall, Ken

2008-01-01

Using molecular statics simulations and the embedded atom method, a technique for bending silver nanowires and calculating Young's modulus via continuum mechanics has been developed. The measured Young's modulus values extracted from bending simulations were compared with modulus values calculated from uniaxial tension simulations for a range of nanowire sizes, orientations and geometries. Depending on axial orientation, the nanowires exhibit stiffening or softening under tension and bending as size decreases. Bending simulations typically result in a greater variation of Young's modulus values with nanowire size compared with tensile deformation, which indicates a loading-method-dependent size effect on elastic properties at sub-5 nm wire diameters. Since the axial stress is maximized at the lateral surfaces in bending, the loading-method-dependent size effect is postulated to be primarily a result of differences in nanowire surface and core elastic modulus. The divergence of Young's modulus from the bulk modulus in these simulations occurs at sizes below the range in which experiments have demonstrated a size scale effect on elastic properties of metallic nanowires. This difference indicates that other factors beyond native metallic surface properties play a role in experimentally observed nanowire elastic modulus size effects

Acute Compressive Ulnar Neuropathy in a Patient of Dengue Fever: An Unusual Presentation

Directory of Open Access Journals (Sweden)

Anil K Mehtani

2013-04-01

Full Text Available Introduction: Dengue haemorrhagic fever is known for its haemorrhagic and neurologic complications. Neurologic complications are caused by three mechanism namely neurotropism, systemic complications causing encephalopathy and postinfectious immune-mediated mechanisms. However acute compressive neuropathy due to haemorrhage is not frequent and we could find no literature describing this Case Report: We report a case of acute compressive ulnar neuropathy due to peri neural hematoma, following an attempt at intravenous cannulation in the cubital fossa in a patient of dengue haemorrhagic fever with thrombocytopenia. Immediate fasciotomy and removal of haematoma was performed to relieve the symptoms. Conclusion: Compression neuropathies can be seen in dengue hemorrhagic fever and removal of compressing hematoma relieves symptoms. Keywords: Dengue haemmorrhagic fever; coagulopathy; peri neural haematoma.

In vivo electrophysiological measurement of the rat ulnar nerve with axonal excitability testing

DEFF Research Database (Denmark)

Wild, Brandon M.; Morris, Renée; Moldovan, Mihai

2018-01-01

Electrophysiology enables the objective assessment of peripheral nerve function in vivo. Traditional nerve conduction measures such as amplitude and latency detect chronic axon loss and demyelination, respectively. Axonal excitability techniques "by threshold tracking" expand upon these measures...... by providing information regarding the activity of ion channels, pumps and exchangers that relate to acute function and may precede degenerative events. As such, the use of axonal excitability in animal models of neurological disorders may provide a useful in vivo measure to assess novel therapeutic...... interventions. Here we describe an experimental setup for multiple measures of motor axonal excitability techniques in the rat ulnar nerve. The animals are anesthetized with isoflurane and carefully monitored to ensure constant and adequate depth of anesthesia. Body temperature, respiration rate, heart rate...

Lower Body Stiffness Modulation Strategies in Well Trained Female Athletes.

Science.gov (United States)

Millett, Emma L; Moresi, Mark P; Watsford, Mark L; Taylor, Paul G; Greene, David A

2016-10-01

Millett, EL, Moresi, MP, Watsford, ML, Taylor, PG, and Greene, DA. Lower body stiffness modulation strategies in well trained female athletes. J Strength Cond Res 30(10): 2845-2856, 2016-Lower extremity stiffness quantifies the relationship between the amount of leg compression and the external load to which the limb are subjected. This study aimed to assess differences in leg and joint stiffness and the subsequent kinematic and kinetic control mechanisms between athletes from various training backgrounds. Forty-seven female participants (20 nationally identified netballers, 13 high level endurance athletes and 14 age and gender matched controls) completed a maximal unilateral countermovement jump, drop jump and horizontal jump to assess stiffness. Leg stiffness, joint stiffness and associated mechanical parameters were assessed with a 10 camera motion analysis system and force plate. No significant differences were evident for leg stiffness measures between athletic groups for any of the tasks (p = 0.321-0.849). However, differences in joint stiffness and its contribution to leg stiffness, jump performance outcome measures and stiffness control mechanisms were evident between all groups. Practitioners should consider the appropriateness of the task utilised in leg stiffness screening. Inclusion of mechanistic and/or more sports specific tasks may be more appropriate for athletic groups.

Tissue-engineered rhesus monkey nerve grafts for the repair of long ulnar nerve defects: similar outcomes to autologous nerve grafts

Directory of Open Access Journals (Sweden)

Chang-qing Jiang

2016-01-01

Full Text Available Acellular nerve allografts can help preserve normal nerve structure and extracellular matrix composition. These allografts have low immunogenicity and are more readily available than autologous nerves for the repair of long-segment peripheral nerve defects. In this study, we repaired a 40-mm ulnar nerve defect in rhesus monkeys with tissue-engineered peripheral nerve, and compared the outcome with that of autograft. The graft was prepared using a chemical extract from adult rhesus monkeys and seeded with allogeneic Schwann cells. Pathomorphology, electromyogram and immunohistochemistry findings revealed the absence of palmar erosion or ulcers, and that the morphology and elasticity of the hypothenar eminence were normal 5 months postoperatively. There were no significant differences in the mean peak compound muscle action potential, the mean nerve conduction velocity, or the number of neurofilaments between the experimental and control groups. However, outcome was significantly better in the experimental group than in the blank group. These findings suggest that chemically extracted allogeneic nerve seeded with autologous Schwann cells can repair 40-mm ulnar nerve defects in the rhesus monkey. The outcomes are similar to those obtained with autologous nerve graft.

Tissue-engineered rhesus monkey nerve gratfs for the repair of long ulnar nerve defects：similar outcomes to autologous nerve gratfs

Institute of Scientific and Technical Information of China (English)

Chang-qing Jiang; Jun Hu; Jian-ping Xiang; Jia-kai Zhu; Xiao-lin Liu; Peng Luo

2016-01-01

Acellular nerve allogratfs can help preserve normal nerve structure and extracellular matrix composition. These allogratfs have low immu-nogenicity and are more readily available than autologous nerves for the repair of long-segment peripheral nerve defects. In this study, we repaired a 40-mm ulnar nerve defect in rhesus monkeys with tissue-engineered peripheral nerve, and compared the outcome with that of autogratf. The gratf was prepared using a chemical extract from adult rhesus monkeys and seeded with allogeneic Schwann cells. Pathomo-rphology, electromyogram and immunohistochemistry ifndings revealed the absence of palmar erosion or ulcers, and that the morphology and elasticity of the hypothenar eminence were normal 5 months postoperatively. There were no signiifcant differences in the mean peak compound muscle action potential, the mean nerve conduction velocity, or the number of neuroiflaments between the experimental and control groups. However, outcome was signiifcantly better in the experimental group than in the blank group. These ifndings suggest that chemically extracted allogeneic nerve seeded with autologous Schwann cells can repair 40-mm ulnar nerve defects in the rhesus monkey. The outcomes are similar to those obtained with autologous nerve gratf.

Evaluation of the performance of three tenodesis techniques for the treatment of scapholunate instability: flexion-extension and radial-ulnar deviation.

Science.gov (United States)

Alonso-Rasgado, Teresa; Zhang, Qing-Hang; Jimenez-Cruz, David; Bailey, Colin; Pinder, Elizabeth; Mandaleson, Avanthi; Talwalkar, Sumedh

2017-11-25

Chronic scapholunate ligament (SL) injuries are difficult to treat and can lead to wrist dysfunction. Whilst several tendon reconstruction techniques have been employed in the management of SL instability, SL gap reappearance after surgery has been reported. Using a finite element model and cadaveric study data, we investigated the performance of the Corella, scapholunate axis (SLAM) and modified Brunelli tenodesis (MBT) techniques. Scapholunate dorsal and volar gap and angle were obtained following virtual surgery undertaken using each of the three reconstruction methods with the wrist positioned in flexion, extension, ulnar deviation and radial deviation, in addition to the ulnar-deviated clenched fist and neutral positions. From the study, it was found that, following simulated scapholunate interosseous ligament rupture, the Corella technique was better able to restore the SL gap and angle close to the intact ligament for all wrist positions investigated, followed by SLAM and MBT. The results suggest that for the tendon reconstruction techniques, the use of multiple junction points between scaphoid and lunate may be of benefit. Graphical abstract The use of multiple junction points between scaphoid and lunate may be of benefit for tendon reconstruction techniques.

Smoothed particle hydrodynamics simulations of flow separation at bends

NARCIS (Netherlands)

Hou, Q.; Kruisbrink, A.C.H.; Pearce, F.R.; Tijsseling, A.S.; Yue, T.

2014-01-01

The separated flow in two-dimensional bends is numerically simulated for a right-angled bend with different ratios of the channel widths and for a symmetric bend with different turning angles. Unlike the potential flow solutions that have several restrictive assumptions, the Euler equations are

Smoothed particle hydrodynamics simulations of flow separation at bends

NARCIS (Netherlands)

Hou, Q.; Kruisbrink, A.C.H.; Pearce, F.R.; Tijsseling, A.S.; Yue, T.

2013-01-01

The separated flow in two-dimensional bends is numerically simulated for a right-angled bend with different ratios of the channel widths and for a symmetric bend with different turning angles. Unlike the potential flow solutions that have several restrictive assumptions, the Euler equations are

Stiffness Evolution in Frozen Sands Subjected to Stress Changes

KAUST Repository

Dai, Sheng; Santamarina, Carlos

2017-01-01

Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

Stiffness Evolution in Frozen Sands Subjected to Stress Changes

KAUST Repository

Dai, Sheng

2017-04-21

Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

Ramifications of structural deformations on collapse loads of critically cracked pipe bends under in-plane bending and internal pressure

Energy Technology Data Exchange (ETDEWEB)

Sasidharan, Sumesh; Arunachalam, Veerappan; Subramaniam, Shanmugam [Dept. of Mechanical Engineering, National Institute of Technology, Tiruchirappalli (India)

2017-02-15

Finite-element analysis based on elastic-perfectly plastic material was conducted to examine the influence of structural deformations on collapse loads of circumferential through-wall critically cracked 90 .deg. pipe bends undergoing in-plane closing bending and internal pressure. The critical crack is defined for a through-wall circumferential crack at the extrados with a subtended angle below which there is no weakening effect on collapse moment of elbows subjected to in-plane closing bending. Elliptical and semioval cross sections were postulated at the bend regions and compared. Twice-elastic-slope method was utilized to obtain the collapse loads. Structural deformations, namely, ovality and thinning, were each varied from 0% to 20% in steps of 5% and the normalized internal pressure was varied from 0.2 to 0.6. Results indicate that elliptic cross sections were suitable for pipe ratios 5 and 10, whereas for pipe ratio 20, semioval cross sections gave satisfactory solutions. The effect of ovality on collapse loads is significant, although it cancelled out at a certain value of applied internal pressure. Thinning had a negligible effect on collapse loads of bends with crack geometries considered.

The influence of end constraints on smooth pipe bends

International Nuclear Information System (INIS)

Thomson, G.; Spence, J.

1981-01-01

With present trends in the power industries towards higher operating temperatures and pressures, problems associated with the design and safety assessment of pipework systems have become increasingly complex. Within such systems, the importance of smooth pipe bends is well established. The work which will be presented will attempt to clarify the situation and unify the results. An analytical solution of the problem of a linear elastic smooth pipe bend with end constraints under in-plane bending will be presented. The analysis will deal with constraints in the form of flanged tangents of any length. The analysis employs the theorem of minimum total potential energy with suitable kinematically admissible displacements in the form of Fourier series. The integrations and minimisation were performed numerically, thereby permitting the removal of several of the assumptions made by previous authors. Typical results for flexibilities will be given along with comparisons with other works. The differences in some earlier theory are clarified and other more recent work using different solution techniques is substantiated. The bend behaviour is shown to be strongly influenced by the pipe bend parameter, the bend angle, the tangent pipe length and the bend/cross-sectional radius ratio. (orig./GL)

Experimental Challenges to Stiffness as a Transport Paradigm

Science.gov (United States)

Luce, T. C.

2017-10-01

Transport in plasmas is treated experimentally as a relationship between gradients and fluxes in analogy to the random-walk problem. Gyrokinetic models often predict strong increases in local flux for small increases in local gradient when above a threshold, holding all other parameters fixed. This has been named `stiffness'. The radial scalelength is then expected to vary little with source strength as a result of high stiffness. To probe the role of ExB shearing on stiffness in the DIII-D tokamak, two neutral beam injection power scans in H-mode plasmas were specially crafted-one with constant, low torque and one with increasing torque. The ion heat, electron heat, and ion toroidal momentum transport do not show expected signatures of stiffness, while the ion particle transport does. The ion heat transport shows the clearest discrepancy; the normalized heat flux drops with increasing inverse ion temperature scalelength. ExB shearing affects the transport magnitude, but not the scalelength dependence. Linear gyrofluid (TGLF) and nonlinear gyrokinetic (GYRO) predictions show stiff ion heat transport around the experimental profiles. The ion temperature gradient required to match the ion heat flux with increasing auxiliary power is not correctly described by TGLF, even when parameters are varied within the experimental uncertainties. TGLF also underpredicts transport at smaller radii, but overpredicts transport at larger radii. Independent of the theory/experiment comparison, it is not clear that the theoretical definition of stiffness yields any prediction about parameter scans such as the power scans here, because the quantities that must be held fixed to quantify stiffness are varied. A survey of recent literature indicated that profile resilience is routinely attributed to stiffness, but simple model calculations show profile resilience does not imply stiffness. Taken together, these observations challenge the use of local stiffness as a paradigm for explaining

Stiffness Evaluation of High Temperature Superconductor Bearing Stiffness for 10 kWh Superconductor Flywheel Energy Storage System

International Nuclear Information System (INIS)

Park, B. J.; Jung, S. Y.; Lee, J. P.; Park, B. C.; Kim, C. H.; Han, S. C.; Du, S. G.; Han, Y. H.; Sung, T. H.

2009-01-01

A superconductor flywheel energy storage(SFES) system is mainly act an electro-mechanical battery which transfers mechanical energy into electrical form and vice versa. SFES system consists of a pair of non-contacting High Temperature Superconductor (HTS) bearings with a very low frictional loss. But it is essential to design an efficient HTS bearing considering with rotor dynamic properties through correct calculation of stiffness in order to support a huge composite flywheel rotor with high energy storage density. Static properties of HTS bearings provide data to solve problems which may occur easily in a running system. Since stiffness to counter vibration is the main parameter in designing an HTS bearing system, we investigate HTS bearing magnetic force through static properties between the Permanent Magnet(PM) and HTS. We measured axial / radial stiffness and found bearing stiffness can be easily changed by activated vibration direction between PM and HTS bulk. These results are used to determine the optimal design for a 10 kWh SFES.

On the role of CFRP reinforcement for wood beams stiffness

Science.gov (United States)

Ianasi, A. C.

2015-11-01

In recent years, carbon fiber composites have been increasingly used in different ways in reinforcing structural elements. Specifically, the use of composite materials as a reinforcement for wood beams under bending loads requires paying attention to several aspects of the problem such as the number of the composite layers applied on the wood beams. Study consolidation of composites revealed that they are made by bonding fibrous material impregnated with resin on the surface of various elements, to restore or increase the load carrying capacity (bending, cutting, compression or torque) without significant damage of their rigidity. Fibers used in building applications can be fiberglass, aramid or carbon. Items that can be strengthened are concrete, brick, wood, steel and stone, and in terms of structural beams, walls, columns and floors. This paper describes an experimental study which was designed to evaluate the effect of composite material on the stiffness of the wood beams. It proposes a summary of the fundamental principles of analysis of composite materials and the design and use. The type of reinforcement used on the beams is the carbon fiber reinforced polymer (CFRP) sheet and plates and also an epoxy resin for bonding all the elements. Structural epoxy resins remain the primary choice of adhesive to form the bond to fiber-reinforced plastics and are the generally accepted adhesives in bonded CFRP-wood connections. The advantages of using epoxy resin in comparison to common wood-laminating adhesives are their gap-filling qualities and the low clamping pressures that are required to form the bond between carbon fiber plates or sheets and the wood beams. Mechanical tests performed on the reinforced wood beams showed that CFRP materials may produce flexural displacement and lifting increases of the beams. Observations of the experimental load-displacement relationships showed that bending strength increased for wood beams reinforced with CFRP composite plates

Stiffness and damping in mechanical design

National Research Council Canada - National Science Library

Rivin, Eugene I

1999-01-01

... important conceptual issues are stiffness of mechanical structures and their components and damping in mechanical systems sensitive to and/or generating vibrations. Stiffness and strength are the most important criteria for many mechanical designs. However, although there are hundreds of books on various aspects of strength, and strength issues ar...

Bends and splitters in graphene nanoribbon waveguides

DEFF Research Database (Denmark)

Zhu, Xiaolong; Yan, Wei; Mortensen, N. Asger

2013-01-01

We investigate the performance of bends and splitters in graphene nanoribbon waveguides. Although the graphene waveguides are lossy themselves, we show that bends and splitters do not induce any additional loss provided that the nanoribbon width is sub-wavelength. We use transmission line theory...

The Effect of Shoe Insole Stiffness on Leg Stiffness during Stance Phase of Running in Two Different Speeds ‎among Active Men

Directory of Open Access Journals (Sweden)

Zeinab Tazike-Lemeski

2016-08-01

Full Text Available Introduction: The effect of shoe insoles with different characteristics and in different running speeds on lower-limb stiffness is still ‎controversial. The aim of this study was to investigate the effect of two types of insoles (soft and semi-rigid in two ‎different running speeds on leg stiffness during stance phase of running among active men.‎ Materials and Methods: ‎15 male students without any background of lower extremity injury were selected. Subjects were asked to run with ‎two controlled velocities of 3.0 ± 0.2 and 5.0 ± 0.1 m/s in control and insole conditions (soft and semi-rigid on a ‎force plate, placed on the middle of 15-meter runway. The cinematics and cinetics of motion were measured and ‎calculated using 5 video cameras and one force plate. The leg stiffness was achieved via dividing the vertical ‎ground reaction force by leg compression. Two-factor repeated measures ANOVA was used to test the hypothesis at ‎the significance level of P £ 0.050.‎ Results: There was a significant difference between the two types of insoles on leg stiffness. In fact, semi-rigid insole significantly increased leg stiffness (P < 0.001. However, this discrepancy was not related to the running speed (P = 0.999. In addition, there was no significant difference between the two different speeds on leg stiffness (P = 0.632. Conclusion: It seems that the increase in shoe insole stiffness may increase the leg stiffness. Furthermore, the effect of insole ‎stiffness is not related to the running speed, and leg stiffness will remains constant in low to medium running speeds.‎

Effect of platelet-rich plasma combined with demineralised bone matrix on bone healing in rabbit ulnar defects.

Science.gov (United States)

Galanis, Vasilios; Fiska, Alice; Kapetanakis, Stylianos; Kazakos, Konstantinos; Demetriou, Thespis

2017-09-01

This study evaluates the effect of autologous platelet-rich plasma (PRP) combined with xenogeneic demineralised bone matrix (DBM) on bone healing of critical-size ulnar defects (2-2.5 times the ulnar diameter) in New Zealand White rabbits. Critical-size defects were created unilaterally in the ulna of 36 rabbits, while keeping the contralateral limb intact. They were divided into three groups. In Group A, the defect was filled with autologous PRP and in Group B, with autologous PRP combined with DBM; in Group C, the defect remained empty. The rabbits were euthanised 12 weeks postoperatively. Radiological, biomechanical and histological assessments were carried out and statistical analysis of the results was performed. Group B had significantly higher radiological and histological scores than Groups A and C. Defects in Group B showed significant new bone formation, whereas there was minimal or no new bone formation in Groups A and C. Only specimens in Group B showed macroscopic bone union. Biomechanical evaluation of the treated and intact contralateral limbs in Group B showed significant differences. In this study, statistically significant enhancement of bone healing was found in critical-size defects treated with PRP and DBM, as shown by radiological findings, gross assessment, and biomechanical and histopathological results. Defects in the two other groups remained unbridged. Therefore, PRP was effective only when it was used in combination with a bone graft. Copyright: © Singapore Medical Association

The stable stiffness triangle - drained sand during deformation cycles

DEFF Research Database (Denmark)

Sabaliauskas, Tomas; Ibsen, Lars Bo

2017-01-01

Cyclic, drained sand stiffness was observed using the Danish triaxial appa- ratus. New, deformation dependant soil property (the stable stiffness triangle) was detected. Using the the stable stiffness triangle, secant stiffness of drained sand was plausible to predict (and control) even during ir...... findings can find application in off-shore, seismic and other engi- neering practice, or inspire new branches of research and modelling wherever dynamic, cyclic or transient loaded sand is encountered....

Characterization and study of photonic crystal fibres with bends

International Nuclear Information System (INIS)

Belhadj, W.; AbdelMalek, F.; Bouchriha, H.

2006-01-01

Analysis of a photonic crystal fibre (PRCF) with bends is presented. Using the versatile finite difference time domain method, the modal characteristics of the PCFs are found. Possibilities of employing PCFs with bends in sensing are discussed. It is found that a large evanescent field is present when the bend angle exceeds 45 o

Direct measurement of the intrinsic ankle stiffness during standing

NARCIS (Netherlands)

Vlutters, Mark; Vlutters, M.; Boonstra, Tjitske; Schouten, Alfred Christiaan; van der Kooij, Herman

2015-01-01

Ankle stiffness contributes to standing balance, counteracting the destabilizing effect of gravity. The ankle stiffness together with the compliance between the foot and the support surface make up the ankle-foot stiffness, which is relevant to quiet standing. The contribution of the intrinsic

Operator-Based Preconditioning of Stiff Hyperbolic Systems

International Nuclear Information System (INIS)

Reynolds, Daniel R.; Samtaney, Ravi; Woodward, Carol S.

2009-01-01

We introduce an operator-based scheme for preconditioning stiff components encountered in implicit methods for hyperbolic systems of partial differential equations posed on regular grids. The method is based on a directional splitting of the implicit operator, followed by a characteristic decomposition of the resulting directional parts. This approach allows for solution to any number of characteristic components, from the entire system to only the fastest, stiffness-inducing waves. We apply the preconditioning method to stiff hyperbolic systems arising in magnetohydro- dynamics and gas dynamics. We then present numerical results showing that this preconditioning scheme works well on problems where the underlying stiffness results from the interaction of fast transient waves with slowly-evolving dynamics, scales well to large problem sizes and numbers of processors, and allows for additional customization based on the specific problems under study

Disk-bend ductility tests for irradiated materials

International Nuclear Information System (INIS)

Klueh, R.L.; Braski, D.N.

1984-01-01

We modified the HEDL disk-bend test machine and are using it to qualitatively screen alloys that are susceptible to embrittlement caused by irradiation. Tests designed to understand the disk-bend test in relation to a uniaxial test are discussed. Selected results of tests of neutron-irradiated material are also presented

Tratamento da síndrome do túnel ulnar pela técnica da epicondilectomia parcial medial do cotovelo Treatment of cubital tunnel syndrome using the technique of medial partial epicondylectomy of the elbow

Directory of Open Access Journals (Sweden)

Marcio Eduardo de Melo Viveiros

2008-12-01

Full Text Available OBJETIVO: Analisamos retrospectivamente os resultados de 21 casos de síndrome cubital tratados cirurgicamente com a técnica da epicondilectomia parcial medial. MÉTODOS: No período de fevereiro de 2001 a outubro de 2006, 21 pacientes com síndrome do canal cubital foram tratados pela técnica da epicondilectomia parcial medial do cotovelo associada à neurólise do nervo ulnar. Destes, 12 (57,1% eram do sexo masculino. O lado direito foi o acometido em 15 (71,4% pacientes. A média da idade dos pacientes foi de 51,6 anos. Pela graduação de McGowan, seis (28,6% pacientes encontravam-se no grau I, 11 (52,3%, no grau II e quatro (19,1%, no grau III do período pré-operatório. RESULTADOS: O tempo médio de acompanhamento pós-operatório foi de 25,7 meses. No pós-operatório, os pacientes foram avaliados conforme a escala de pontos de Bishop, sendo que nove (42,8% apresentavam resultados excelentes, sete (33,3%, bons, três (14,2%, regulares e dois (9,5%, ruins. Nesta série, não se encontraram como complicações a instabilidade em valgo residual, a lesão permanente do nervo ulnar, a recidiva da compressão ou a subluxação do nervo ulnar. As complicações encontradas foram perda do arco de movimento em um (4,7% caso, infecção superficial em um (4,7% e um (4,7% com dor residual. CONCLUSÃO: Os resultados apresentados permitem concluir que a epicondilectomia parcial medial do cotovelo associada à neurólise do nervo ulnar é eficiente e segura para o tratamento da síndrome do canal cubital.OBJECTIVE: The authors made a retrospective analysis of the results of 21 cases of cubital syndrome that were surgically treated with the partial medial epicondylectomy. METHODS: From February 2001 to October 2006, 21 patients with cubital tunnel syndrome were treated with the technique of elbow partial medial epicondylectomy associated to neurolysis of the ulnar nerve. Of these patients, 12 (57.1% were male. The right side was involved in 15 (71

Three dimensional vibration and bending analysis of carbon nanotubes embedded in elastic medium based on theory of elasticity

Directory of Open Access Journals (Sweden)

M. Shaban

Full Text Available This paper studies free vibration and bending behavior of singlewalled carbon nanotubes (SWCNTs embedded on elastic medium based on three-dimensional theory of elasticity. To accounting the size effect of carbon nanotubes, non-local theory is adopted to shell model. The nonlocal parameter is incorporated into all constitutive equations in three dimensions. The surrounding medium is modeled as two-parameter elastic foundation. By using Fourier series expansion in axial and circumferential direction, the set of coupled governing equations are reduced to the ordinary differential equations in thickness direction. Then, the state-space method as an efficient and accurate method is used to solve the resulting equations analytically. Comprehensive parametric studies are carried out to show the influences of the nonlocal parameter, radial and shear elastic stiffness, thickness-to-radius ratio and radiusto-length ratio.

Biomechanical constraints on the feedforward regulation of endpoint stiffness.

Science.gov (United States)

Hu, Xiao; Murray, Wendy M; Perreault, Eric J

2012-10-01

Although many daily tasks tend to destabilize arm posture, it is still possible to have stable interactions with the environment by regulating the multijoint mechanics of the arm in a task-appropriate manner. For postural tasks, this regulation involves the appropriate control of endpoint stiffness, which represents the stiffness of the arm at the hand. Although experimental studies have been used to evaluate endpoint stiffness control, including the orientation of maximal stiffness, the underlying neural strategies remain unknown. Specifically, the relative importance of feedforward and feedback mechanisms has yet to be determined due to the difficulty separately identifying the contributions of these mechanisms in human experiments. This study used a previously validated three-dimensional musculoskeletal model of the arm to quantify the degree to which the orientation of maximal endpoint stiffness could be changed using only steady-state muscle activations, used to represent feedforward motor commands. Our hypothesis was that the feedforward control of endpoint stiffness orientation would be significantly constrained by the biomechanical properties of the musculoskeletal system. Our results supported this hypothesis, demonstrating substantial biomechanical constraints on the ability to regulate endpoint stiffness throughout the workspace. The ability to regulate stiffness orientation was further constrained by additional task requirements, such as the need to support the arm against gravity or exert forces on the environment. Together, these results bound the degree to which slowly varying feedforward motor commands can be used to regulate the orientation of maximum arm stiffness and provide a context for better understanding conditions in which feedback control may be needed.

Influence of flock coating on bending rigidity of woven fabrics

Science.gov (United States)

Ozdemir, O.; Kesimci, M. O.

2017-10-01

This work presents the preliminary results of our efforts that focused on the effect of the flock coating on the bending rigidity of woven fabrics. For this objective, a laboratory scale flocking unit is designed and flocked samples of controlled flock density are produced. Bending rigidity of the samples with different flock densities are measured on both flocked and unflocked sides. It is shown that the bending rigidity depends on both flock density and whether the side to be measured is flocked or not. Adhesive layer thickness on the bending rigidity is shown to be dramatic. And at higher basis weights, flock density gets less effective on bending rigidity.

Simvastatin Ameliorates Matrix Stiffness-Mediated Endothelial Monolayer Disruption.

Directory of Open Access Journals (Sweden)

Marsha C Lampi

Full Text Available Arterial stiffening accompanies both aging and atherosclerosis, and age-related stiffening of the arterial intima increases RhoA activity and cell contractility contributing to increased endothelium permeability. Notably, statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA reductase inhibitors whose pleiotropic effects include disrupting small GTPase activity; therefore, we hypothesized the statin simvastatin could be used to attenuate RhoA activity and inhibit the deleterious effects of increased age-related matrix stiffness on endothelial barrier function. Using polyacrylamide gels with stiffnesses of 2.5, 5, and 10 kPa to mimic the physiological stiffness of young and aged arteries, endothelial cells were grown to confluence and treated with simvastatin. Our data indicate that RhoA and phosphorylated myosin light chain activity increase with matrix stiffness but are attenuated when treated with the statin. Increases in cell contractility, cell-cell junction size, and indirect measurements of intercellular tension that increase with matrix stiffness, and are correlated with matrix stiffness-dependent increases in monolayer permeability, also decrease with statin treatment. Furthermore, we report that simvastatin increases activated Rac1 levels that contribute to endothelial barrier enhancing cytoskeletal reorganization. Simvastatin, which is prescribed clinically due to its ability to lower cholesterol, alters the endothelial cell response to increased matrix stiffness to restore endothelial monolayer barrier function, and therefore, presents a possible therapeutic intervention to prevent atherogenesis initiated by age-related arterial stiffening.

Hydrodynamic processes in sharp meander bends and their morphological implications

NARCIS (Netherlands)

Blanckaert, K.

2011-01-01

The migration rate of sharp meander bends exhibits large variance and indicates that some sharply curved bends tend to stabilize. These observations remain unexplained. This paper examines three hydrodynamic processes in sharp bends with fixed banks and discusses their morphological implications:

Analysis of Dynamic Stiffness of Bridge Cap-Pile System

Directory of Open Access Journals (Sweden)

Jinhui Chu

2018-01-01

Full Text Available In order to investigate the applicability of dynamic stiffness for bridge cap-pile system, a laboratory test was performed. A numerical model was also built for this type of system. The impact load was applied on the cap top and the dynamic stiffness was analysed. Then, the effect of the effective friction area between pile and soil was also considered. Finally, the dynamic stiffness relationship between the single pile and the cap-pile system was also compared. The results show that the dynamic stiffness is a sensitive index and can well reflect the static characteristics of the pile at the elastic stage. There is a significant positive correlation between the vertical dynamic stiffness index and bearing capacity of the cap-pile system in the similar formation environment. For the cap-pile system with four piles, the dynamic stiffness is about four times as large as the single pile between 10 and 20 Hz.

Stiff quantum polymers

OpenAIRE

Kleinert, H.

2009-01-01

At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

Arterial Stiffness in Children: Pediatric Measurement and Considerations

Science.gov (United States)

Savant, Jonathan D.; Furth, Susan L.; Meyers, Kevin E.C.

2014-01-01

Background Arterial stiffness is a natural consequence of aging, accelerated in certain chronic conditions, and predictive of cardiovascular events in adults. Emerging research suggests the importance of arterial stiffness in pediatric populations. Methods There are different indices of arterial stiffness. The present manuscript focuses on carotid-femoral pulse wave velocity and pulse wave analysis, although other methodologies are discussed. Also reviewed are specific measurement considerations for pediatric populations and the literature describing arterial stiffness in children with certain chronic conditions (primary hypertension, obesity, diabetes, chronic kidney disease, hypercholesterolemia, genetic syndromes involving vasculopathy, and solid organ transplant recipients). Conclusions The measurement of arterial stiffness in children is feasible and, under controlled conditions, can give accurate information about the underlying state of the arteries. This potentially adds valuable information about the functionality of the cardiovascular system in children with a variety of chronic diseases well beyond that of the brachial artery blood pressure. PMID:26587447

Bending spring rate investigation of nanopipette for cell injection

Science.gov (United States)

Shen, Yajing; Zhang, Zhenhai; Fukuda, Toshio

2015-04-01

Bending of nanopipette tips during cell penetration is a major cause of cell injection failure. However, the flexural rigidity of nanopipettes is little known due to their irregular structure. In this paper, we report a quantitative method to estimate the flexural rigidity of a nanopipette by investigating its bending spring rate. First nanopipettes with a tip size of 300 nm are fabricated from various glass tubes by laser pulling followed by focused ion beam (FIB) milling. Then the bending spring rate of the nanopipettes is investigated inside a scanning electron microscope (SEM). Finally, a yeast cell penetration test is performed on these nanopipettes, which have different bending spring rates. The results show that nanopipettes with a higher bending spring rate have better cell penetration capability, which confirms that the bending spring rate may well reflect the flexural rigidity of a nanopipette. This method provides a quantitative parameter for characterizing the mechanical property of a nanopipette that can be potentially taken as a standard specification in the future. This general method can also be used to estimate other one-dimensional structures for cell injection, which will greatly benefit basic cell biology research and clinical applications.

Bending spring rate investigation of nanopipette for cell injection

International Nuclear Information System (INIS)

Shen, Yajing; Zhang, Zhenhai; Fukuda, Toshio

2015-01-01

Bending of nanopipette tips during cell penetration is a major cause of cell injection failure. However, the flexural rigidity of nanopipettes is little known due to their irregular structure. In this paper, we report a quantitative method to estimate the flexural rigidity of a nanopipette by investigating its bending spring rate. First nanopipettes with a tip size of 300 nm are fabricated from various glass tubes by laser pulling followed by focused ion beam (FIB) milling. Then the bending spring rate of the nanopipettes is investigated inside a scanning electron microscope (SEM). Finally, a yeast cell penetration test is performed on these nanopipettes, which have different bending spring rates. The results show that nanopipettes with a higher bending spring rate have better cell penetration capability, which confirms that the bending spring rate may well reflect the flexural rigidity of a nanopipette. This method provides a quantitative parameter for characterizing the mechanical property of a nanopipette that can be potentially taken as a standard specification in the future. This general method can also be used to estimate other one-dimensional structures for cell injection, which will greatly benefit basic cell biology research and clinical applications. (paper)

Aerosol deposition in bends with turbulent flow

Energy Technology Data Exchange (ETDEWEB)

McFarland, A.R.; Gong, H.; Wente, W.B. [Texas A& M Univ., College Station, TX (United States)] [and others

1997-08-01

The losses of aerosol particles in bends were determined numerically for a broad range of design and operational conditions. Experimental data were used to check the validity of the numerical model, where the latter employs a commercially available computational fluid dynamics code for characterizing the fluid flow field and Lagrangian particle tracking technique for characterizing aerosol losses. Physical experiments have been conducted to examine the effect of curvature ratio and distortion of the cross section of bends. If it curvature ratio ({delta} = R/a) is greater than about 4, it has little effect on deposition, which is in contrast with the recommendation given in ANSI N13.1-1969 for a minimum curvature ratio of 10. Also, experimental results show that if the tube cross section is flattened by 25% or less, the flattening also has little effect on deposition. Results of numerical tests have been used to develop a correlation of aerosol penetration through a bend as a function of Stokes number (Stk), curvature ratio ({delta}) and the bend angle ({theta}). 17 refs., 10 figs., 2 tabs.

Slice of a LEP bending magnet

CERN Multimedia

This is a slice of a LEP dipole bending magnet, made as a concrete and iron sandwich. The bending field needed in LEP is small (about 1000 Gauss), equivalent to two of the magnets people stick on fridge doors. Because it is very difficult to keep a low field steady, a high field was used in iron plates embedded in concrete. A CERN breakthrough in magnet design, LEP dipoles can be tuned easily and are cheaper than conventional magnets.

Limit moments for non circular cross-section (elliptical) pipe bends

International Nuclear Information System (INIS)

Spence, J.

1977-01-01

A number of experiment studies have been reported or are underway which investigate limit moments applied to pipe bends. Some theoretical work is also available. However, most of the work has been confined to nominally circular cross-section bends and little account has been taken of the practical problem of manufacturing tolerances. Many methods of manufacture result in bends which are not circular in cross-section but have an oval or elliptical shape. The present paper extends previous analyses on circular bends to cater for initially elliptical cross-sections. The loading is primarily in plane bending but out of plane is also considered and several independent methods are presented. No previous information is known to the authors. Upper and lower bound limit moments are derived first of all from existing linear elastic analyses and secondly upper bound moments are derived via a plastic analogy from existing stationary creep results. It is also shown that the creep information on design factors for bends can be used to obtain a reasonable estimate of the complete moment/strain behaviour of a bend or indeed a system. (Auth.)

Ball Bearing Stiffnesses- A New Approach Offering Analytical Expressions

Science.gov (United States)

Guay, Pascal; Frikha, Ahmed

2015-09-01

Space mechanisms use preloaded ball bearings in order to withstand the severe vibrations during launch.The launch strength requires the calculation of the bearing stiffness, but this calculation is complex. Nowadays, there is no analytical expression that gives the stiffness of a bearing. Stiffness is computed using an iterative algorithm such as Newton-Raphson, to solve the nonlinear system of equations.This paper aims at offering a simplified analytical approach, based on the assumption that the contact angle is constant. This approach gives analytical formulas of the stiffness of preloaded ball bearing.

Pseudarthrosis of radial shaft with dislocation of heads of radial and ulnar bones (case report

Directory of Open Access Journals (Sweden)

M. E. Puseva

2013-01-01

Full Text Available The authors presented a rare clinical case - the injury of forearm complicated by the formation of the pseudarthrosis of the radial shaft in combination with old dislocation of heads the radius and ulna. The differentiated approach to the choice of surgical tactics was proposed, which consists of several consistent stages: taking free autotransplant from the crest of iliac bone, resection of pseudarthrosis of radius with replacement of the bone defect by the graft for restoration of anatomic length, conducting combined strained osteosynthesis and elimination of dislocation of a head of radial and ulnar bones by transosseous osteosynthesis. The chosen treatment strategy allowed to restore the anatomy and function of the upper extremity.

Plant fibre composites - porosity and stiffness

DEFF Research Database (Denmark)

Madsen, Bo; Thygesen, Anders; Lilholt, Hans

2009-01-01

Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition...... of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...

Molecular Cues Guiding Matrix Stiffness in Liver Fibrosis

Directory of Open Access Journals (Sweden)

Takaoki Saneyasu

2016-01-01

Full Text Available Tissue and matrix stiffness affect cell properties during morphogenesis, cell growth, differentiation, and migration and are altered in the tissue remodeling following injury and the pathological progression. However, detailed molecular mechanisms underlying alterations of stiffness in vivo are still poorly understood. Recent engineering technologies have developed powerful techniques to characterize the mechanical properties of cell and matrix at nanoscale levels. Extracellular matrix (ECM influences mechanical tension and activation of pathogenic signaling during the development of chronic fibrotic diseases. In this short review, we will focus on the present knowledge of the mechanisms of how ECM stiffness is regulated during the development of liver fibrosis and the molecules involved in ECM stiffness as a potential therapeutic target for liver fibrosis.

Is chronic obstructive pulmonary disease associated with increased arterial stiffness?

DEFF Research Database (Denmark)

Janner, Julie H; McAllister, David A; Godtfredsen, Nina S

2012-01-01

We hypothesize that airflow limitation is associated with increasing arterial stiffness and that having COPD increases a non-invasive measure of arterial stiffness - the aortic augmentation index (AIx) - independently of other CVD risk factors.......We hypothesize that airflow limitation is associated with increasing arterial stiffness and that having COPD increases a non-invasive measure of arterial stiffness - the aortic augmentation index (AIx) - independently of other CVD risk factors....

A Rapid Aeroelasticity Optimization Method Based on the Stiffness characteristics

OpenAIRE

Yuan, Zhe; Huo, Shihui; Ren, Jianting

2018-01-01

A rapid aeroelasticity optimization method based on the stiffness characteristics was proposed in the present study. Large time expense in static aeroelasticity analysis based on traditional time domain aeroelasticity method is solved. Elastic axis location and torsional stiffness are discussed firstly. Both torsional stiffness and the distance between stiffness center and aerodynamic center have a direct impact on divergent velocity. The divergent velocity can be adjusted by changing the cor...

Turbulent flow computation in a circular U-Bend

Directory of Open Access Journals (Sweden)

Miloud Abdelkrim

2014-03-01

Full Text Available Turbulent flows through a circular 180° curved bend with a curvature ratio of 3.375, defined as the the bend mean radius to pipe diameter is investigated numerically for a Reynolds number of 4.45×104. The computation is performed for a U-Bend with full long pipes at the entrance and at the exit. The commercial ANSYS FLUENT is used to solve the steady Reynolds–Averaged Navier–Stokes (RANS equations. The performances of standard k-ε and the second moment closure RSM models are evaluated by comparing their numerical results against experimental data and testing their capabilities to capture the formation and extend this turbulence driven vortex. It is found that the secondary flows occur in the cross-stream half-plane of such configurations and primarily induced by high anisotropy of the cross-stream turbulent normal stresses near the outer bend.

Turbulent flow computation in a circular U-Bend

Science.gov (United States)

Miloud, Abdelkrim; Aounallah, Mohammed; Belkadi, Mustapha; Adjlout, Lahouari; Imine, Omar; Imine, Bachir

2014-03-01

Turbulent flows through a circular 180° curved bend with a curvature ratio of 3.375, defined as the the bend mean radius to pipe diameter is investigated numerically for a Reynolds number of 4.45×104. The computation is performed for a U-Bend with full long pipes at the entrance and at the exit. The commercial ANSYS FLUENT is used to solve the steady Reynolds-Averaged Navier-Stokes (RANS) equations. The performances of standard k-ɛ and the second moment closure RSM models are evaluated by comparing their numerical results against experimental data and testing their capabilities to capture the formation and extend this turbulence driven vortex. It is found that the secondary flows occur in the cross-stream half-plane of such configurations and primarily induced by high anisotropy of the cross-stream turbulent normal stresses near the outer bend.

Damper modules with adapted stiffness ratio

Energy Technology Data Exchange (ETDEWEB)

Sonnenburg, R.; Stretz, A. [ZF Sachs AG, Entwicklungszentrum, Schweinfurt (Germany)

2011-07-15

A mechanism for the excitation of piston rod vibrations in automotive damper modules is discussed by a simple model. An improved nonlinear model based on elasticity effects leads to good simulation results. It is shown theoretically and experimentally that the adaptation of the stiffness of the piston rod bushing to the ''stiffness'' of the damper force characteristic can eliminate the piston rod oscillations completely. (orig.)

Rotational and peak torque stiffness of rugby shoes.

Science.gov (United States)

Ballal, Moez S; Usuelli, Federico Giuseppe; Montrasio, Umberto Alfieri; Molloy, Andy; La Barbera, Luigi; Villa, Tomaso; Banfi, Giuseppe

2014-09-01

Sports people always strive to avoid injury. Sports shoe designs in many sports have been shown to affect traction and injury rates. The aim of this study is to demonstrate the differing stiffness and torque in rugby boots that are designed for the same effect. Five different types of rugby shoes commonly worn by scrum forwards were laboratory tested for rotational stiffness and peak torque on a natural playing surface generating force patterns that would be consistent with a rugby scrum. The overall internal rotation peak torque was 57.75±6.26 Nm while that of external rotation was 56.55±4.36 Nm. The Peak internal and external rotational stiffness were 0.696±0.1 and 0.708±0.06 Nm/deg respectively. Our results, when compared to rotational stiffness and peak torques of football shoes published in the literature, show that shoes worn by rugby players exert higher rotational and peak torque stiffness compared to football shoes when tested on the same natural surfaces. There was significant difference between the tested rugby shoes brands. In our opinion, to maximize potential performance and lower the potential of non-contact injury, care should be taken in choosing boots with stiffness appropriate to the players main playing role. Copyright © 2014 Elsevier Ltd. All rights reserved.

An Experimental Study of Force Involved in Manual Rebar Bending Process

Science.gov (United States)

Deepu, Sasi; Vishnu, Rajendran S.; Harish, Mohan T.; Bhavani, Rao R.

2018-02-01

The work presents an experimental method of understanding the force applied during a manual rebar bending process. The study tracks the force with the variation of the angle of bend and the elapsed time from the start to the end of a complete manual rebar bending process. A sample of expert rebar bending labourers are used for conducting the experiment and the data processed to set a performance standard. If a simulator based rebar bending training can be provided for a novice, this standard can be used as a matrix to define how close a novice rebar bender is closing to the expertise.

Static stiffness modeling of a novel hybrid redundant robot machine

International Nuclear Information System (INIS)

Li Ming; Wu Huapeng; Handroos, Heikki

2011-01-01

This paper presents a modeling method to study the stiffness of a hybrid serial-parallel robot IWR (Intersector Welding Robot) for the assembly of ITER vacuum vessel. The stiffness matrix of the basic element in the robot is evaluated using matrix structural analysis (MSA); the stiffness of the parallel mechanism is investigated by taking account of the deformations of both hydraulic limbs and joints; the stiffness of the whole integrated robot is evaluated by employing the virtual joint method and the principle of virtual work. The obtained stiffness model of the hybrid robot is analytical and the deformation results of the robot workspace under certain external load are presented.

Evaluation of bending rigidity behaviour of ultrasonic seaming on woven fabrics

Science.gov (United States)

Şevkan Macit, Ayşe; Tiber, Bahar

2017-10-01

In recent years ultrasonic seaming that is shown as an alternative method to conventional seaming has been investigated by many researchers. In our study, bending behaviour of this alternative method is examined by changing various parameters such as fabric type, seam type, roller type and seaming velocity. For this purpose fifteen types of sewn fabrics were tested according to bending rigidity test standard before and after washing processes and results were evaluated through SPSS statistical analyze programme. Consequently, bending length values of the ultrasonically sewn fabrics are found to be higher than the bending length values of conventionally sewn fabrics and the effects of seam type on bending length are seen statistically significant. Also it is observed that bending length values are in relationship with the rest of the parameters excluding roller type.

Subspace methods for identification of human ankle joint stiffness.

Science.gov (United States)

Zhao, Y; Westwick, D T; Kearney, R E

2011-11-01

Joint stiffness, the dynamic relationship between the angular position of a joint and the torque acting about it, describes the dynamic, mechanical behavior of a joint during posture and movement. Joint stiffness arises from both intrinsic and reflex mechanisms, but the torques due to these mechanisms cannot be measured separately experimentally, since they appear and change together. Therefore, the direct estimation of the intrinsic and reflex stiffnesses is difficult. In this paper, we present a new, two-step procedure to estimate the intrinsic and reflex components of ankle stiffness. In the first step, a discrete-time, subspace-based method is used to estimate a state-space model for overall stiffness from the measured overall torque and then predict the intrinsic and reflex torques. In the second step, continuous-time models for the intrinsic and reflex stiffnesses are estimated from the predicted intrinsic and reflex torques. Simulations and experimental results demonstrate that the algorithm estimates the intrinsic and reflex stiffnesses accurately. The new subspace-based algorithm has three advantages over previous algorithms: 1) It does not require iteration, and therefore, will always converge to an optimal solution; 2) it provides better estimates for data with high noise or short sample lengths; and 3) it provides much more accurate results for data acquired under the closed-loop conditions, that prevail when subjects interact with compliant loads.

Numerical simulation of laser bending of AISI 304 plate with a ...

African Journals Online (AJOL)

Keywords: laser bending; process modeling; bending angle; response surface models. ... (Shi et al., 2007) presented numerical simulation of bending for with different shapes of laser ..... Matlab 2011a application code is used to develop and.

Magnetic field of longitudinal gradient bend

Science.gov (United States)

Aiba, Masamitsu; Böge, Michael; Ehrlichman, Michael; Streun, Andreas

2018-06-01

The longitudinal gradient bend is an effective method for reducing the natural emittance in light sources. It is, however, not a common element. We have analyzed its magnetic field and derived a set of formulae. Based on the derivation, we discuss how to model the longitudinal gradient bend in accelerator codes that are used for designing electron storage rings. Strengths of multipole components can also be evaluated from the formulae, and we investigate the impact of higher order multipole components in a very low emittance lattice.

Bending energy of buckled edge dislocations

Science.gov (United States)

Kupferman, Raz

2017-12-01

The study of elastic membranes carrying topological defects has a longstanding history, going back at least to the 1950s. When allowed to buckle in three-dimensional space, membranes with defects can totally relieve their in-plane strain, remaining with a bending energy, whose rigidity modulus is small compared to the stretching modulus. In this paper we study membranes with a single edge dislocation. We prove that the minimum bending energy associated with strain-free configurations diverges logarithmically with the size of the system.

A lightweight, biological structure with tailored stiffness: The feather vane.

Science.gov (United States)

Sullivan, Tarah N; Pissarenko, Andreï; Herrera, Steven A; Kisailus, David; Lubarda, Vlado A; Meyers, Marc A

2016-09-01

The flying feathers of birds are keratinous appendages designed for maximum performance with a minimum weight penalty. Thus, their design contains ingenious combinations of components that optimize lift, stiffness, aerodynamics, and damage resistance. This design involves two main parts: a central shaft that prescribes stiffness and lateral vanes which allows for the capture of air. Within the feather vane, barbs branch from the shaft and barbules branch from barbs, forming a flat surface which ensures lift. Microhooks at the end of barbules hold barbs tightly together, providing the close-knit, unified structure of the feather vane and enabling a repair of the structure through the reattachment of un-hooked junctions. Both the shaft and barbs are lightweight biological structures constructed of keratin using the common motif of a solid shell and cellular interior. The cellular core increases the resistance to buckling with little added weight. Here we analyze the detailed structure of the feather barb and, for the first time, explain its flexural stiffness in terms of the mechanics of asymmetric foam-filled beams subjected to bending. The results are correlated and validated with finite element modeling. We compare the flexure of single barbs as well as arrays of barbs and find that the interlocking adherence of barbs to one another enables a more robust structure due to minimized barb rotation during deflection. Thus, the flexure behavior of the feather vane can be tailored by the adhesive hooking between barbs, creating a system that mitigates damage. A simplified three-dimensional physical model for this interlocking mechanism is constructed by additive manufacturing. The exceptional architecture of the feather vane will motivate the design of bioinspired structures with tailored and unique properties ranging from adhesives to aerospace materials. Despite its importance to bird flight, literature characterizing the feather vane is extremely limited. The feather

Effect of Bend Radius on Magnitude and Location of Erosion in S-Bend

Directory of Open Access Journals (Sweden)

Quamrul H. Mazumder

2015-01-01

Full Text Available Solid particle erosion is a mechanical process that removes material by the impact of solid particles entrained in the flow. Erosion is a leading cause of failure of oil and gas pipelines and fittings in fluid handling industries. Different approaches have been used to control or minimize damage caused by erosion in particulated gas-solid or liquid-solid flows. S-bend geometry is widely used in different fluid handling equipment that may be susceptible to erosion damage. The results of a computational fluid dynamic (CFD simulation of diluted gas-solid and liquid-solid flows in an S-bend are presented in this paper. In addition to particle impact velocity, the bend radius may have significant influence on the magnitude and the location of erosion. CFD analysis was performed at three different air velocities (15.24 m/s–45.72 m/s and three different water velocities (0.1 m/s–10 m/s with entrained solid particles. The particle sizes used in the analysis range between 50 and 300 microns. Maximum erosion was observed in water with 10 m/s, 250-micron particle size, and a ratio of 3.5. The location of maximum erosion was observed in water with 10 m/s, 300-micron particle size, and a ratio of 3.5. Comparison of CFD results with available literature data showed reasonable and good agreement.

Pulling a polymer with anisotropic stiffness near a sticky wall

International Nuclear Information System (INIS)

Tabbara, R; Owczarek, A L

2012-01-01

We solve exactly a two-dimensional partially directed walk model of a semi-flexible polymer that has one end tethered to a sticky wall, while a pulling force away from the adsorbing surface acts on the free end of the walk. This model generalizes a number of previously considered adsorption models by incorporating individual horizontal and vertical stiffness effects, in competition with a variable pulling angle. A solution to the corresponding generating function is found by means of the kernel method. While the phases and related phase transitions are similar in nature to those found previously the analysis of the model in terms of its physical variables highlights various novel structures in the shapes of the phase diagrams and related behaviour of the polymer. We review the results of previously considered sub-cases, augmenting these findings to include analysis with respect to the model’s physical variables—namely, temperature, pulling force, pulling angle away from the surface, stiffness strength and the ratio of vertical to horizontal stiffness potentials, with our subsequent analysis for the general model focusing on the effect that stiffness has on this pulling angle range. In analysing the model with stiffness we also pay special attention to the case where only vertical stiffness is included. The physical analysis of this case reveals behaviour more closely resembling that of an upward pulling force acting on a polymer than it does of a model where horizontal stiffness acts. The stiffness–temperature phase diagram exhibits re-entrance for low temperatures, previously only seen for three-dimensional or co-polymer models. For the most general model we delineate the shift in the physical behaviour as we change the ratio of vertical to horizontal stiffness between the horizontal-only and the vertical-only stiffness regimes. We find that a number of distinct physical characteristics will only be observed for a model where the vertical stiffness dominates

Galvanic vestibular stimulation may improve anterior bending posture in Parkinson's disease.

Science.gov (United States)

Okada, Yohei; Kita, Yorihiro; Nakamura, Junji; Kataoka, Hiroshi; Kiriyama, Takao; Ueno, Satoshi; Hiyamizu, Makoto; Morioka, Shu; Shomoto, Koji

2015-05-06

This study investigated the effects of binaural monopolar galvanic vestibular stimulation (GVS), which likely stimulates the bilateral vestibular system, on the anterior bending angle in patients with Parkinson's disease (PD) with anterior bending posture in a single-blind, randomized sham-controlled crossover trial. The seven PD patients completed two types of stimulation (binaural monopolar GVS and sham stimulation) applied in a random order 1 week apart. We measured each patient's anterior bending angles while he or she stood with eyes open and eyes closed before/after the stimulations. The anterior bending angles in both the eyes-open and the eyes-closed conditions were significantly reduced after the GVS. The amount of change in the eyes-closed condition post-GVS was significantly larger than that by sham stimulation. The amount of change in anterior bending angles in the GVS condition was not significantly correlated with Unified Parkinson's Disease Rating Scale motor score, disease duration, the duration of the postural deformities, and the anterior bending angles before the GVS. Binaural monopolar GVS might improve anterior bending posture in PD patients, irrespective of the duration and the severity of disease and postural deformities. Binaural monopolar GVS might be a novel treatment strategy to improve anterior bending posture in PD.

Influence of stiffness on CHF for horizontal tubes under LPLF conditions

Energy Technology Data Exchange (ETDEWEB)

Baburajan, P.K. [Nuclear Safety Analysis Division, AERB, Niyamak Bhavan, 400094 (India); Bisht, Govind Singh [Department of Mechanical Engineering, IIT Bombay, 400076 (India); Gaikwad, Avinash J. [Nuclear Safety Analysis Division, AERB, Niyamak Bhavan, 400094 (India); Prabhu, S.V., E-mail: svprabhu@iitb.ac.in [Department of Mechanical Engineering, IIT Bombay, 400076 (India)

2014-10-01

Highlights: • Effect of stiffness on the CHF in horizontal tube under LPLF conditions is studied. • CHF increases with the increase in stiffness. • Correlation for the prediction of CHF as a function of stiffness is developed. • Correlation for mass flux at CHF in terms of stiffness and initial mass flux is given. • RELAP5 is capable of predicting the effect of stiffness on CHF. - Abstract: Studies reported in the past on critical heat flux (CHF) are mostly limited to vertical flow, large channel diameter, high pressure and high mass flux. Since horizontal flow is commonly encountered in boiler tubes, refrigerating equipments and nuclear reactor fuel channels (PHWR), there is a need to understand horizontal flow CHF, generate sufficient experimental database and to develop reliable predictive method. Few studies are reported on the effect of upstream flow restrictions on flow instabilities and CHF. The present work investigates the effect of upstream flow restriction on CHF in horizontal flow at near atmospheric pressure conditions. In the present study, stiffness is defined as the ratio of upstream flow restriction pressure drop to the test section pressure drop. The classification of a flow boiling system as soft or stiff on the basis of quantification of the stiffness is attempted. Experimental data shows an increase in the CHF with the increase in the stiffness for a given initial mass flux. A correlation for the prediction of CHF under various stiffness conditions is developed. A correlation is suggested to predict the mass flux at CHF as a function of stiffness and initial mass flux. Modeling and transient analysis of the stiffness effect on CHF is carried out using the thermal hydraulic system code RELAP5. The predicted phenomena are in agreement with the experimental observations.

Fatigue crack paths under the influence of changes in stiffness

Directory of Open Access Journals (Sweden)

G. Kullmer

2016-02-01

Full Text Available An important topic of the Collaborative Research Centre TRR 30 of the Deutsche Forschungsgemeinschaft (DFG is the crack growth behaviour in graded materials. In addition, the growth of cracks in the neighbourhood of regions and through regions with different material properties belongs under this topic. Due to the different material properties, regions with differing stiffness compared to the base material may arise. Regions with differing stiffness also arise from ribs, grooves or boreholes. Since secure findings on the propagation behaviour of fatigue cracks are essential for the evaluation of the safety of components and structures, the growth of cracks near changes in stiffness has to be considered, too. Depending on the way a crack penetrates the zone of influence of such a change in stiffness and depending on whether this region is more compliant or stiffer than the surrounding area the crack may grow towards or away from this region. Both cases result in curved crack paths that cannot be explained only by the global loading situation. To evaluate the influence of regions with differing stiffness on the path of fatigue cracks the paths and the stress intensity factors of cracks growing near and through regions with differing stiffness are numerically determined with the program system ADAPCRACK3D. Therefore, arrangements of changes in stiffness modelled as material inclusions with stiffness properties different from the base material or modelled as ribs and grooves are systematically varied to develop basic conclusions about the crack growth behaviour near and through changes in stiffness.

On prestress stiffness analysis of bolt-plate contact assemblies

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard; Pedersen, Pauli

2008-01-01

, but with finite element (FE) and contact analysis, it is possible to find the stiffness of the member. In the case of many connections and for practical applications, it is not suitable to make a full FE analysis. The purpose of the present paper is to find simplified expressions for the stiffness of the member......, including the case when the width of the member is limited. The calculation of the stiffness is based on the FE, including the solution to the contact problem, and we express the stiffness as a function of the elastic energy in the structure, whereby the definition of the displacements related...

Low frequency noise reduction using stiff light composite panels

Institute of Scientific and Technical Information of China (English)

DENG Yongchang; LIN Weizheng

2003-01-01

The experiment presented in this paper is to investigate and analyze the noise reduction at low frequency using stiff light composite panels. Since these composite panels are made of lightweight and stiff materials, this actuation strategy will enable the creation of composite panels for duct noise control without using traditional heavy structural mass. The results suggest that the mass-spring resonance absorption in the case of a comparatively stiff thick panel with a thin flexible plate is more efficient with minimum weight, when subjected to low-frequency (<500 Hz). The efficiency of the panel absorber depends on the mass of the thin flexible plate and the stiffness of the panel.

Study of Transport and Micro-structural properties of Magnesium Di-Boride Strand under react and bend mode and bend and react mode

International Nuclear Information System (INIS)

Kundu, Ananya; Kumar Das, Subrat; Bano, Anees; Pradhan, Subrata

2017-01-01

I-V characterization of commercial multi-filamentary Magnesium Di-Boride (MgB 2 ) wire of diameter 0.83 mm were studied in Cryocooler at self-field I-V characterization system under both react and bend mode and bend and react mode for a range of temperature 6 K - 25 K. This study is of practical technical relevance where the heat treatment of the superconducting wire makes the wire less flexible for winding in magnet and in other applications. In the present work the bending diameter was varied from 40 mm to 20 mm and for each case critical current (I c ) of the strand is measured for above range of temperature. A customized sample holder is fabricated and thermally anchored with the 2 nd cold stage of Cryocooler. It is observed from the measurement that the strand is more susceptible to degradation for react and bend cases. The transport measurement of the strand was accompanied by SEM analyses of bend samples. Also the tensile strength of the raw strands and the heat treated strands were carried out at room temperature in Universal Testing Machine (UTM) to have an estimate about the limiting winding tension value during magnet fabrication. (paper)

Elastin in large artery stiffness and hypertension

Science.gov (United States)

Wagenseil, Jessica E.; Mecham, Robert P.

2012-01-01

Large artery stiffness, as measured by pulse wave velocity (PWV), is correlated with high blood pressure and may be a causative factor in essential hypertension. The extracellular matrix components, specifically the mix of elastin and collagen in the vessel wall, determine the passive mechanical properties of the large arteries. Elastin is organized into elastic fibers in the wall during arterial development in a complex process that requires spatial and temporal coordination of numerous proteins. The elastic fibers last the lifetime of the organism, but are subject to proteolytic degradation and chemical alterations that change their mechanical properties. This review discusses how alterations in the amount, assembly, organization or chemical properties of the elastic fibers affect arterial stiffness and blood pressure. Strategies for encouraging or reversing alterations to the elastic fibers are addressed. Methods for determining the efficacy of these strategies, by measuring elastin amounts and arterial stiffness, are summarized. Therapies that have a direct effect on arterial stiffness through alterations to the elastic fibers in the wall may be an effective treatment for essential hypertension. PMID:22290157

Advanced damper with negative structural stiffness elements

International Nuclear Information System (INIS)

Dong, Liang; Lakes, Roderic S

2012-01-01

Negative stiffness is understood as the occurrence of a force in the same direction as the imposed deformation. Structures and composites with negative stiffness elements enable a large amplification in damping. It is shown in this work, using an experimental approach, that when a flexible flat-ends column is aligned in a post-buckled condition, a negative structural stiffness and large hysteresis (i.e., high damping) can be achieved provided the ends of the column undergo tilting from flat to edge contact. Stable axial dampers with initial modulus equivalent to that of the parent material and with enhanced damping were designed and built using constrained negative stiffness effects entailed by post-buckled press-fit flat-ends columns. Effective damping of approximately 1 and an effective stiffness–damping product of approximately 1.3 GPa were achieved in such stable axial dampers consisting of PMMA columns. This is a considerable improvement for this figure of merit (i.e., the stiffness–damping product), which generally cannot exceed 0.6 GPa for currently used damping layers. (paper)

Systematic profiling of spatiotemporal tissue and cellular stiffness in the developing brain.

Science.gov (United States)

Iwashita, Misato; Kataoka, Noriyuki; Toida, Kazunori; Kosodo, Yoichi

2014-10-01

Accumulating evidence implicates the significance of the physical properties of the niche in influencing the behavior, growth and differentiation of stem cells. Among the physical properties, extracellular stiffness has been shown to have direct effects on fate determination in several cell types in vitro. However, little evidence exists concerning whether shifts in stiffness occur in vivo during tissue development. To address this question, we present a systematic strategy to evaluate the shift in stiffness in a developing tissue using the mouse embryonic cerebral cortex as an experimental model. We combined atomic force microscopy measurements of tissue and cellular stiffness with immunostaining of specific markers of neural differentiation to correlate the value of stiffness with the characteristic features of tissues and cells in the developing brain. We found that the stiffness of the ventricular and subventricular zones increases gradually during development. Furthermore, a peak in tissue stiffness appeared in the intermediate zone at E16.5. The stiffness of the cortical plate showed an initial increase but decreased at E18.5, although the cellular stiffness of neurons monotonically increased in association with the maturation of the microtubule cytoskeleton. These results indicate that tissue stiffness cannot be solely determined by the stiffness of the cells that constitute the tissue. Taken together, our method profiles the stiffness of living tissue and cells with defined characteristics and can therefore be utilized to further understand the role of stiffness as a physical factor that determines cell fate during the formation of the cerebral cortex and other tissues. © 2014. Published by The Company of Biologists Ltd.

Evaluating pulp stiffness from fibre bundles by ultrasound

Science.gov (United States)

Karppinen, Timo; Montonen, Risto; Määttänen, Marjo; Ekman, Axel; Myllys, Markko; Timonen, Jussi; Hæggström, Edward

2012-06-01

A non-destructive ultrasonic tester was developed to measure the stiffness of pulp bundles. The mechanical properties of pulp are important when estimating the behaviour of paper under stress. Currently available pulp tests are tedious and alter the fibres structurally and mechanically. The developed tester employs (933 ± 15) kHz tweezer-like ultrasonic transducers and time-of-flight measurement through (9.0 ± 2.5) mm long and (0.8 ± 0.1) mm thick fibre bundles kept at (19.1 ± 0.4) °C and (62 ± 1)% RH. We determined the stiffness of soft wood pulps produced by three kraft pulping modifications: standard kraft pulp, (5.2 ± 0.4) GPa, prehydrolysis kraft pulp, (4.3 ± 0.4) GPa, and alkali extracted prehydrolysis kraft pulp, (3.3 ± 0.4) GPa. Prehydrolysis and alkali extraction processes mainly lowered the hemicellulose content of the pulps, which essentially decreased the fibre-wall stiffness hence impairing the stiffness of the fibre networks. Our results indicate that the method allows ranking of pulps according to their stiffness determined from bundle-like samples taken at an early phase of the papermaking process.

Shakedown boundary determination of a 90° back-to-back pipe bend subjected to steady internal pressures and cyclic in-plane bending moments

International Nuclear Information System (INIS)

Abdalla, Hany F.

2014-01-01

No experimental data exist within open literature, to the best knowledge of the author, for determining shakedown boundaries of 90° back-to-back pipe bends. Ninety degree back-to-back pipe bends are extensively utilized within piping networks of nuclear submarines and modern turbofan aero-engines where space limitation is considered a paramount concern. In the current research, the 90° back-to-back pipe bend setup analyzed is subjected to a spectrum of steady internal pressures and cyclic in-plane bending moments. A previously developed direct non-cyclic simplified technique for determining elastic shakedown limit loads is utilized to generate the elastic shakedown boundary of the analyzed structure. The simplified technique outcomes showed excellent correlation with the results of full elastic–plastic cyclic loading finite element simulations. - Highlights: • No shakedown experimental data exist for 90° back-to-back pipe bends. • A non-cyclic technique is utilized to generate the elastic shakedown boundary. • The non-cyclic technique succeeded in generating the structure's Bree diagram. • The non-cyclic technique correlated well with full cyclic loading FE simulations

A new variable stiffness suspension system: passive case

Directory of Open Access Journals (Sweden)

O. M. Anubi

2013-02-01

Full Text Available This paper presents the design, analysis, and experimental validation of the passive case of a variable stiffness suspension system. The central concept is based on a recently designed variable stiffness mechanism. It consists of a horizontal control strut and a vertical strut. The main idea is to vary the load transfer ratio by moving the location of the point of attachment of the vertical strut to the car body. This movement is controlled passively using the horizontal strut. The system is analyzed using an L2-gain analysis based on the concept of energy dissipation. The analyses, simulation, and experimental results show that the variable stiffness suspension achieves better performance than the constant stiffness counterpart. The performance criteria used are; ride comfort, characterized by the car body acceleration, suspension deflection, and road holding, characterized by tire deflection.

Spontaneous bending of 2D molecular bottle-brush

NARCIS (Netherlands)

Subbotin, A; Jong, J; ten Brinke, G

Using a scaling approach we consider a 2D comb copolymer brush under bending deformations. We show that the rectilinear brush is locally stable and can be characterized by a persistence length lambda increasing with the molecular weight of grafting side chains as lambda similar to M-3. A bending

Rotating Square-Ended U-Bend Using Low-Reynolds-Number Models

Directory of Open Access Journals (Sweden)

Konstantinos-Stephen P. Nikas

2005-01-01

bend is better reproduced by the low-Re models. Turbulence levels within the rotating U-bend are underpredicted, but DSM models produce a more realistic distribution. Along the leading side, all models overpredict heat transfer levels just after the bend. Along the trailing side, the heat transfer predictions of the low-Re DSM with the NYap, are close to the measurements.

Association of Parental Hypertension With Arterial Stiffness in Nonhypertensive Offspring

DEFF Research Database (Denmark)

Andersson, Charlotte; Quiroz, Rene; Enserro, Danielle

2016-01-01

High arterial stiffness seems to be causally involved in the pathogenesis of hypertension. We tested the hypothesis that offspring of parents with hypertension may display higher arterial stiffness before clinically manifest hypertension, given that hypertension is a heritable condition. We compa......, in this community-based sample of young, nonhypertensive adults, we observed greater arterial stiffness in offspring of parents with hypertension. These observations are consistent with higher vascular stiffness at an early stage in the pathogenesis of hypertension.......High arterial stiffness seems to be causally involved in the pathogenesis of hypertension. We tested the hypothesis that offspring of parents with hypertension may display higher arterial stiffness before clinically manifest hypertension, given that hypertension is a heritable condition. We...... compared arterial tonometry measures in a sample of 1564 nonhypertensive Framingham Heart Study third-generation cohort participants (mean age: 38 years; 55% women) whose parents were enrolled in the Framingham Offspring Study. A total of 468, 715, and 381 participants had 0 (referent), 1, and 2 parents...

The effects of bending speed on the lumbo-pelvic kinematics and movement pattern during forward bending in people with and without low back pain.

Science.gov (United States)

Tsang, Sharon M H; Szeto, Grace P Y; Li, Linda M K; Wong, Dim C M; Yip, Millie M P; Lee, Raymond Y W

2017-04-17

Impaired lumbo-pelvic movement in people with low back pain during bending task has been reported previously. However, the regional mobility and the pattern of the lumbo-pelvic movement were found to vary across studies. The inconsistency of the findings may partly be related to variations in the speed at which the task was executed. This study examined the effects of bending speeds on the kinematics and the coordination lumbo-pelvic movement during forward bending, and to compare the performance of individuals with and without low back pain. The angular displacement, velocity and acceleration of the lumbo-pelvic movement during the repeated forward bending executed at five selected speeds were acquired using the three dimensional motion tracking system in seventeen males with low back pain and eighteen males who were asymptomatic. The regional kinematics and the degree of coordination of the lumbo-pelvic movement during bending was compared and analysed between two groups. Significantly compromised performance in velocity and acceleration of the lumbar spine and hip joint during bending task at various speed levels was shown in back pain group (p back pain group adopted a uniform lumbo-pelvic pattern across all the speed levels examined. The present findings show that bending speed imposes different levels of demand on the kinematics and pattern of the lumbo-pelvic movement. The ability to regulate the lumbo-pelvic movement pattern during the bending task that executed at various speed levels was shown only in pain-free individuals but not in those with low back pain. Individuals with low back pain moved with a stereotyped strategy at their lumbar spine and hip joints. This specific aberrant lumbo-pelvic movement pattern may have a crucial role in the maintenance of the chronicity in back pain.

Keeping the golden mean: plant stiffness and anatomy as proximal factors driving endophytic oviposition site selection in a dragonfly.

Science.gov (United States)

Matushkina, Natalia; Lambret, Philippe; Gorb, Stanislav

2016-12-01

Oviposition site selection is a crucial component of habitat selection in dragonflies. The presence of appropriate oviposition plants at breeding waters is considered to be one of the key habitat determinants for species laying eggs endophytically. Thus, Lestes macrostigma, a species which is regarded as threatened in Europe because of its highly disjunct distribution, typically prefers to lay eggs in the sea club rush Bolboschoenus maritimus. However, little is known about how the anatomical and mechanical properties of plant tissues determine the choice of L. macrostigma females. We examined green shoots of six plant species used by L. macrostigma for oviposition, either in the field (actual oviposition plants) or under experimental conditions (potential oviposition plants), to analyse anatomical and mechanical properties of shoots in a framework of known preferences regarding plant substrates for oviposition. As expected, the anatomy of shoots differed between representatives of two plant families, Cyperaceae and Juncaceae, most essentially in the distribution of supporting bundles and the presence of large aeriferous cavities that may affect egg placing within a shoot. The force necessary to puncture the tested plant samples ranged from 360 to 3298 mN, and their local stiffness ranged from 777 to 3363N/m. We show that the shoots of B. maritimus, the plant most preferred by L. macrostigma, have intermediate characteristics regarding both the stiffness and specific anatomical characteristics. The bending stiffness of the ovipositor in L. macrostigma was estimated as 1414N/m, one of the highest values recorded for zygopteran dragonflies so far. The ecological and behavioural implications of plant choice mechanisms in L. macrostigma are discussed in the context of the disjunct distribution of this species. Copyright © 2016 Elsevier GmbH. All rights reserved.

VARIABLE STIFFNESS HAND PROSTHESIS: A SYSTEMATIC REVIEW

Directory of Open Access Journals (Sweden)

S. Cecilia Tapia-Siles

2017-06-01

Full Text Available Prosthetics is an important field in engineering due to the large number of amputees worldwide and the associated problems such as limited functionality of the state of the art. An important functionality of the human hand is its capability of adjusting the stiffness of the joints depending on the currently performed task. For the development of new technology it is important to understand the limitations of existing resources. As part of our efforts to develop a variable stiffness grasper for developing countries a systematic review was performed covering technology of body powered and myoelectric hand prosthesis. Focus of the review is readiness of prosthetic hands regarding their capability of controlling the stiffness of the end effector. Publications sourced through three different digital libraries were systematically reviewed on the basis of the PRISMA standard. We present a search strategy as well as the PRISMA assessment of the resulting records which covered 321 publications. The records were assessed and the results are presented for the ability of devices to control their joint stiffness. The review indicates that body powered prosthesis are preferred to myoelectric hands due to the reduced cost, the simplicity of use and because of their inherent ability to provide feedback to the user. Stiffness control was identified but has not been fully covered in the current state of the art. In addition we summarise the identified requirements on prosthetic hands as well as related information which can support the development of new prosthetics.

Measurement of turbulent flows in a square sectioned 270 .deg. bend

Energy Technology Data Exchange (ETDEWEB)

Cho, Sok Hyu; Lee, Gun Hyee [Wonkwang Univ., Iksan (Korea, Republic of); Chun, Kun Ho [Korea Univ., Seoul (Korea, Republic of)

2000-07-01

Most of the past experimental or analytical studies were performed for the curved bend with a square cross-section. Velocity profiles and Reynolds stresses of the turbulence flow in the 270 degree bend with circular cross-section were measured by a hot-wire anemometer. The mean velocity of primary flowing direction effected by the downstream of bend in the entry region of the bend. The flow in the inner part of the bend slowed the distribution velocity relatively large and unsymmetric phenomenon. In the strong secondary flow occurred when the flow passed in the region of 45 degree to 90 degree. The secondary flow appeared very large value in the neighbor region inner wall.

Measurement of turbulent flows in a square sectioned 270 .deg. bend

International Nuclear Information System (INIS)

Cho, Sok Hyu; Lee, Gun Hyee; Chun, Kun Ho

2000-01-01

Most of the past experimental or analytical studies were performed for the curved bend with a square cross-section. Velocity profiles and Reynolds stresses of the turbulence flow in the 270 degree bend with circular cross-section were measured by a hot-wire anemometer. The mean velocity of primary flowing direction effected by the downstream of bend in the entry region of the bend. The flow in the inner part of the bend slowed the distribution velocity relatively large and unsymmetric phenomenon. In the strong secondary flow occurred when the flow passed in the region of 45 degree to 90 degree. The secondary flow appeared very large value in the neighbor region inner wall

Study of transport and micro-structural properties of magnesium di-boride strand under react and bend mode and bend and react mode

International Nuclear Information System (INIS)

Kundu, Ananya; Das, Subrat Kumar; Bano, Anees; Pradhan, Subrata

2015-01-01

I-V characterization of commercial multi-filamentary Magnesium Di-Boride (MgB 2 ) wire of diameter 0.83 mm were studied in cryocooler based self-field characterization system under both react and bent mode and bent and react mode for a range of temperature 6 K - 25 K. This study is of practical technical relevance where the heat treatment of the superconducting wire makes the sample less flexible for winding in magnet and in other applications. There are limited reported data, available on degradation of MgB 2 wire with bending induced strain in react and wind and wind and react method. In the present work the bending diameter were varied from 80 mm to 20 mm in the interval of 10 mm change of bending diameter and for each case critical current (Ic) of the strand is measured for the above range of temperature. An ETP copper made customized sample holder for mounting the MgB 2 strand was fabricated and is thermally anchored to the cooling stage of the cryocooler. It is seen from the experimental data that in react and bent mode the critical current degrades from 105 A to 87 A corresponding to bending diameter of 80 mm and 20 mm respectively. The corresponding bending strain was analytically estimated and compared with the simulation result. It is also observed that in react and bent mode, the degradation of the transport property of the strand is less as compared to react and bent mode. For bent and react mode in the same sample, the critical current (Ic) was measured to be ∼145 A at 15 K for bending diameter of 20 mm. Apart from studying the bending induced strain on MgB 2 strand, the tensile test of the strand at RT was carried out. The electrical characterizations of the samples were accompanied by the microstructure analyses of the bent strand to examine the bending induced degradation in the grain structure of the strand. All these experimental findings are expected to be used as input to fabricate prototype MgB 2 based magnet. (author)

Tubular lining material for pipelines having bends

Energy Technology Data Exchange (ETDEWEB)

Moringa, A.; Sakaguchi, Y.; Hyodo, M.; Yagi, I.

1987-03-24

A tubular lining material for pipelines having bends or curved portions comprises a tubular textile jacket made of warps and wefts woven in a tubular form overlaid with a coating of a flexible synthetic resin. It is applicable onto the inner surface of a pipeline having bends or curved portions in such manner that the tubular lining material with a binder onto the inner surface thereof is inserted into the pipeline and allowed to advance within the pipeline, with or without the aid of a leading rope-like elongated element, while turning the tubular lining material inside out under fluid pressure. In this manner the tubular lining material is applied onto the inner surface of the pipeline with the binder being interposed between the pipeline and the tubular lining material. The lining material is characterized in that a part of all of the warps are comprised of an elastic yarn around which, over the full length thereof, a synthetic fiber yarn or yarns have been left-and/or right-handedly coiled. This tubular lining material is particularly suitable for lining a pipeline having an inner diameter of 25-200 mm and a plurality of bends, such as gas service pipelines or house pipelines, without occurrence of wrinkles in the lining material in a bend.

Fuzzy model for Laser Assisted Bending Process

Directory of Open Access Journals (Sweden)

Giannini Oliviero

2016-01-01

Full Text Available In the present study, a fuzzy model was developed to predict the residual bending in a conventional metal bending process assisted by a high power diode laser. The study was focused on AA6082T6 aluminium thin sheets. In most dynamic sheet metal forming operations, the highly nonlinear deformation processes cause large amounts of elastic strain energy stored in the formed material. The novel hybrid forming process was thus aimed at inducing the local heating of the mechanically bent workpiece in order to decrease or eliminate the related springback phenomena. In particular, the influence on the extent of springback phenomena of laser process parameters such as source power, scan speed and starting elastic deformation of mechanically bent sheets, was experimentally assessed. Consistent trends in experimental response according to operational parameters were found. Accordingly, 3D process maps of the extent of the springback phenomena according to operational parameters were constructed. The effect of the inherent uncertainties on the predicted residual bending caused by the approximation in the model parameters was evaluated. In particular, a fuzzy-logic based approach was used to describe the model uncertainties and the transformation method was applied to propagate their effect on the residual bending.

Bending of metal-filled carbon nanotube under electron beam irradiation

Directory of Open Access Journals (Sweden)

Abha Misra

2012-03-01

Full Text Available Electron beam irradiation induced, bending of Iron filled, multiwalled carbon nanotubes is reported. Bending of both the carbon nanotube and the Iron contained within the core was achieved using two approaches with the aid of a high resolution electron microscope (HRTEM. In the first approach, bending of the nanotube structure results in response to the irradiation of a pristine kink defect site, while in the second approach, disordered sites induce bending by focusing the electron beam on the graphite walls. The HRTEM based in situ observations demonstrate the potential for using electron beam irradiation to investigate and manipulate the physical properties of confined nanoscale structures.

Ulnar digits contribution to grip strength in patients with thumb carpometacarpal osteoarthritis is less than in normal controls.

Science.gov (United States)

Villafañe, Jorge H; Valdes, Kristin; Angulo-Diaz-Parreño, Santiago; Pillastrini, Paolo; Negrini, Stefano

2015-06-01

Grip testing is commonly used as an objective measure of strength in the hand and upper extremity and is frequently used clinically as a proxy measure of function. Increasing knowledge of hand biomechanics, muscle strength, and prehension patterns can provide us with a better understanding of the functional capabilities of the hand. The objectives of this study were to determine the contribution of ulnar digits to overall grip strength in individuals with thumb carpometacarpal (CMC) osteoarthritis (OA). Thirty-seven subjects participated in the study. This group consisted of 19 patients with CMC OA (aged 60-88 years) and 18 healthy subjects (60-88 years). Three hand configurations were used by the subjects during grip testing: use of the entire hand (index, middle, ring, and little fingers) (IMRL); use of the index, middle, and ring fingers (IMR); and use of only the index and middle fingers (IM). Grip strength findings for the two groups found that compared to their healthy counterparts, CMC OA patients had, on average, a strength deficiency of 45.6, 35.5, and 28.8 % in IMRL, IMR, and IM, respectively. The small finger contribution to grip is 14.3 % and the ring and small finger contribute 34 % in subjects with CMC OA. Grip strength decreases as the number of digits contributing decreased in both groups. The ulnar digits contribution to grip strength is greater than one third of total grip strength in subjects with CMC OA. Individuals with CMC OA demonstrate significantly decreased grip strength when compared to their healthy counterparts.

[Metabolic syndrome and aortic stiffness].

Science.gov (United States)

Simková, A; Bulas, J; Murín, J; Kozlíková, K; Janiga, I

2010-09-01

The metabolic syndrome (MS) is a cluster of risk factors that move the patient into higher level of risk category of cardiovascular disease and the probability of type 2 diabetes mellitus manifestation. Definition of MS is s based on the presence of selected risk factors as: abdominal obesity (lager waist circumpherence), atherogenic dyslipidemia (low value of HDL-cholesterol and increased level of triglycerides), increased fasting blood glucose (or type 2 DM diagnosis), higher blood pressure or antihypertensive therapy. In 2009 there were created harmonizing criteria for MS definition; the condition for assignment of MS is the presence of any 3 criteria of 5 mentioned above. The underlying disorder of MS is an insulin resistance or prediabetes. The patients with MS more frequently have subclinical (preclinical) target organ disease (TOD) which is the early sings of atherosclerosis. Increased aortic stiffness is one of the preclinical diseases and is defined by pathologically increased carotidofemoral pulse wave velocity in aorta (PWV Ao). With the aim to assess the influence of MS on aortic stiffness we examined the group of women with arterial hypertension and MS and compare them with the group of women without MS. The aortic stiffness was examined by Arteriograph--Tensiomed, the equipment working on the oscillometric principle in detection of pulsations of brachial artery. This method determines the global aortic stiffness based on the analysis of the shape of pulse curve of brachial artery. From the cohort of 49 pts 31 had MS, the subgroups did not differ in age or blood pressure level. The mean number of risk factors per person in MS was 3.7 comparing with 1.7 in those without MS. In the MS group there was more frequently abdominal obesity present (87% vs 44%), increased fasting blood glucose (81% vs 22%) and low HDL-cholesterol level. The pulse wave velocity in aorta, PWV Ao, was significantly higher in patients with MS (mean value 10,19 m/s vs 8,96 m

Incomplete (bending) fractures of the mandibular condyle in children

International Nuclear Information System (INIS)

Ahrendt, D.; Swischuk, L.E.; Hayden, C.K. Jr.; Texas Univ., Galveston

1984-01-01

Incomplete, bending or bowing fractures of the mandibular condyle in children frequently go undetected. The reason is that the bending deformity often is subtle and passes for normal. This is especially true if the fractures are bilateral. (orig.)

Sway‐dependent changes in standing ankle stiffness caused by muscle thixotropy

Science.gov (United States)

Sakanaka, Tania E.; Lakie, Martin

2016-01-01

Key points The passive stiffness of the calf muscles contributes to standing balance, although the properties of muscle tissue are highly labile.We investigated the effect of sway history upon intrinsic ankle stiffness and demonstrated reductions in stiffness of up to 43% during conditions of increased baseline sway.This sway dependence was most apparent when using low amplitude stiffness‐measuring perturbations, and the short‐range stiffness component was smaller during periods of high sway.These characteristics are consistent with the thixotropic properties of the calf muscles causing the observed changes in ankle stiffness.Periods of increased sway impair the passive stabilization of standing, demanding more active neural control of balance. Abstract Quiet standing is achieved through a combination of active and passive mechanisms, consisting of neural control and intrinsic mechanical stiffness of the ankle joint, respectively. The mechanical stiffness is partly determined by the calf muscles. However, the viscoelastic properties of muscle are highly labile, exhibiting a strong dependence on movement history. By measuring the effect of sway history upon ankle stiffness, the present study determines whether this lability has consequences for the passive stabilization of human standing. Ten subjects stood quietly on a rotating platform whose axis was collinear with the ankle joint. Ankle sway was increased by slowly tilting this platform in a random fashion, or decreased by fixing the body to a board. Ankle stiffness was measured by using the same platform to simultaneously apply small, brief perturbations (ankle stiffness by up to 43% compared to the body‐fixed condition. Normal quiet stance was associated with intermediate values. The effect was most apparent when using smaller perturbation amplitudes to measure stiffness (0.1 vs. 0.6 deg). Furthermore, torque responses exhibited a biphasic pattern, consisting of an initial steep rise followed by a

Bolted flanged connections subjected to longitudinal bending moments

International Nuclear Information System (INIS)

Blach, A.E.

1992-01-01

Flanges in piping systems and also pressure vessel flanges on tall columns are often subjected to longitudinal bending moments of considerable magnitude, be it from thermal expansion stresses in piping systems or from wind or seismic loadings on tall vertical pressure vessels. Except for the ASME Code, Section III, Subsections NB, NC, and ND, other pressure vessel and piping codes do not contain design ASME Nuclear Power Plant Code (Section III), an empirical formula is given, expressing a longitudinal bending moment in bolted flanged connections in terms of an equivalent internal pressure to be added to the design pressure of the flange. In this paper, an attempt is made to analyse the stresses on flanges and bolting due to external bending moments and to compare flange thicknesses thus obtained with thicknesses required using the equivalent design pressure specified in Subsections NB, NC, and ND. A design method is proposed, based on analysis and experimental work, which may be suitable for flange bending moment analysis when the rules of the Nuclear Power Plant Code are not mandatory. (orig.)

Determination of Ankle and Metatarsophalangeal Stiffness During Walking and Jogging.

Science.gov (United States)

Mager, Fabian; Richards, Jim; Hennies, Malika; Dötzel, Eugen; Chohan, Ambreen; Mbuli, Alex; Capanni, Felix

2018-05-29

Forefoot stiffness has been shown to influence joint biomechanics. However, little or no data exists on metatarsophalangeal stiffness. Twenty-four healthy rearfoot strike runners were recruited from a staff and student population at the University of Central Lancashire. Five repetitions of shod, self-selected speed level walking and jogging were performed. Kinetic and kinematic data were collected using retro-reflective markers placed on the lower limb and foot, to create a three-segment foot model using the Calibrated Anatomical System Technique. Ankle and metatarsophalangeal moments and angles were calculated. Stiffness values were calculated using a linear best fit line of moment versus of angle plots. Paired t-tests were used to compare values between walking and jogging conditions. Significant differences were seen in ankle range of motion (ROM), but not in metatarsophalangeal ROM. Maximum moments were significantly greater in the ankle during jogging, but these were not significantly different at the metatarsophalangeal joint. Average ankle joint stiffness exhibited significantly lower stiffness when walking compared to jogging. However, the metatarsophalangeal joint exhibited significantly greater stiffness when walking compared to jogging. A greater understanding of forefoot stiffness may inform the development of footwear, prosthetic feet and orthotic devices, such as ankle-foot orthoses for walking and sporting activities.

Longitudinal-bending mode micromotor using multilayer piezoelectric actuator.

Science.gov (United States)

Yao, K; Koc, B; Uchino, K

2001-07-01

Longitudinal-bending mode ultrasonic motors with a diameter of 3 mm were fabricated using stacked multilayer piezoelectric actuators, which were self-developed from hard lead zirconate titanate (PZT) ceramic. A bending vibration was converted from a longitudinal vibration with a longitudinal-bending coupler. The motors could be bidirectionally operated by changing driving frequency. Their starting and braking torque were analyzed based on the transient velocity response. With a load of moment of inertia 2.5 x 10(-7) kgm2, the motor showed a maximum starting torque of 127.5 microNm. The braking torque proved to be a constant independent on the motor's driving conditions and was roughly equivalent to the maximum starting torque achievable with our micromotors.

Creep relaxation of fuel pin bending and ovalling stresses

International Nuclear Information System (INIS)

Chan, D.P.; Jackson, R.J.

1979-06-01

Analytical methods for calculating fuel pin cladding bending and ovalling stresses due to pin bundle-duct mechanical interaction taking into account nonlinear creep are presented. Calculated results are in close agreement with finite element results by MARC-CDC program. The methods are used to investigate the effect of creep on the FTR fuel cladding bending and ovalling stresses. It is concluded that the cladding of 316 SS 20% CW and reference design has high creep rates in the FTR core region to keep the bending and ovalling stresses to low levels

Bending-active reciprocal structures based on equilateral polyhedral geometries

DEFF Research Database (Denmark)

Popovic Larsen, Olga; BRANCART, Stijn; DE TEMMERMAN, Niels

2017-01-01

As mutually supported beam structures, reciprocal frames limit the number of components that are joined at each connection to two. However, this system of intermediate connections introduces undesirable bending moments in the beam elements. By utilising elastic deformation to create curved...... of parts of reciprocal bending-active components based on a selection of polyhedral dome types. To simplify the assembly of the structures and avoid the manual bending of the components on site, we introduce the concept of a double-layered, pre-bent component. Finally, this paper presents the development...

Dynamically tuned magnetostrictive spring with electrically controlled stiffness

Science.gov (United States)

Scheidler, Justin J.; Asnani, Vivake M.; Dapino, Marcelo J.

2016-03-01

This paper presents the design and testing of an electrically controllable magnetostrictive spring that has a dynamically tunable stiffness (i.e., a magnetostrictive Varispring). The device enables in situ stiffness tuning or stiffness switching for vibration control applications. Using a nonlinear electromechanical transducer model and an analytical solution of linear, mechanically induced magnetic diffusion, Terfenol-D is shown to have a faster rise time to stepped voltage inputs and a significantly higher magnetic diffusion cut-off frequency relative to Galfenol. A Varispring is manufactured using a laminated Terfenol-D rod. Further rise time reductions are achieved by minimizing the rod’s diameter and winding the electromagnet with larger wire. Dynamic tuning of the Varispring’s stiffness is investigated by measuring the Terfenol-D rod’s strain response to dynamic, compressive, axial forces in the presence of sinusoidal or square wave control currents. The Varispring’s rise time is \\lt 1 ms for 1 A current switches. Continuous modulus changes up to 21.9 GPa and 500 Hz and square wave modulus changes (dynamic {{Δ }}E effect) up to 12.3 GPa and 100 Hz are observed. Stiffness tunability and tuning bandwidth can be considerably increased by operating about a more optimal bias stress and improving the control of the electrical input.

Flow Structure and Channel Morphology at a Confluent-Meander Bend

Science.gov (United States)

Riley, J. D.; Rhoads, B. L.

2009-12-01

Flow structure and channel morphology in meander bends have been well documented. Channel curvature subjects flow through a bend to centrifugal acceleration, inducing a counterbalancing pressure-gradient force that initiates secondary circulation. Transverse variations in boundary shear stress and bedload transport parallel cross-stream movement of high velocity flow and determine spatial patterns of erosion along the outer bank and deposition along the inner bank. Laboratory experiments and numerical modeling of confluent-meander bends, a junction planform that develops when a tributary joins a meandering river along the outer bank of a bend, suggest that flow and channel morphology in such bends deviate from typical patterns. The purpose of this study is to examine three-dimensional (3-D) flow structure and channel morphology at a natural confluent-meander bend. Field data were collected in southeastern Illinois where Big Muddy Creek joins the Little Wabash River near a local maximum of curvature along an elongated meander loop. Measurements of 3-D velocity components were obtained with an acoustic Doppler current profiler (ADCP) for two flow events with differing momentum ratios. Channel bathymetry was also resolved from the four-beam depths of the ADCP. Analysis of velocity data reveals a distinct shear layer flanked by dual helical cells within the bend immediately downstream of the confluence. Flow from the tributary confines flow from the main channel along the inner part of the channel cross section, displacing the thalweg inward, limiting the downstream extent of the point bar, protecting the outer bank from erosion and enabling bar-building along this bank. Overall, this pattern of flow and channel morphology is quite different from typical patterns in meander bends, but is consistent with a conceptual model derived from laboratory experiments and numerical modeling.

On the mechanical modeling of tensegrity columns subject to impact loading

Science.gov (United States)

Amendola, Ada; Favata, Antonino; Micheletti, Andrea

2018-04-01

A physical model of a tensegrity columns is additively manufactured in a titanium alloy. After removing sacrificial supports, such a model is post-tensioned through suitable insertion of Spectra cables. The wave dynamics of the examined system is first experimentally investigated by recording the motion through high-speed cameras assisted by a digital image correlation algorithm, which returns time-histories of the axial displacements of the bases of each prism of the column. Next, the experimental response is mechanically simulated by means of two different models: a stick-and-spring model accounting for the presence of bending-stiff connections between the 3D-printed elements (mixed bending-stretching response), and a tensegrity model accounting for a purely stretching response. The comparison of theory and experiment reveals that the presence of bending-stiff connections weakens the nonlinearity of the wave dynamics of the system. A stretching-dominated response instead supports highly compact solitary waves in the presence of small prestress and negligible bending stiffness of connections.

Ligament rupture and unstable burst behaviors of axial flaws in steam generator U-bends

Energy Technology Data Exchange (ETDEWEB)

Bahn, Chi Bum, E-mail: bahn@pusan.ac.kr [Pusan National University, 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Oh, Young-Jin [KEPCO Engineering & Construction Co. Inc., Seongnam 463-870 (Korea, Republic of); Majumdar, Saurin [Argonne National Laboratory, Lemont, IL 60439 (United States)

2015-11-15

Highlights: • Ligament rupture and unstable burst pressure tests were conducted with U-bends. • In general, U-bends showed higher ligament rupture and burst pressures than straight tubes. • U-bend test data was bounded by 90% lower limit of the probabilistic models for straight tubes. • Prediction models for straight tubes could be conservatively applied to U-bends. - Abstract: Incidents of U-bend cracking in steam generator (SG) tubes have been reported, some of which have led to tube rupture. Experimental and analytical modeling efforts to determine the failure criteria of flawed SG U-bends are limited. To evaluate structural integrity of flawed U-bends, ligament rupture and unstable burst pressure tests were conducted on 57 and 152 mm bend radius U-bends with axial electrical discharge machining notches. In general, the ligament rupture and burst pressures of the U-bends were higher than those of straight tubes with similar notches. To quantitatively address the test data scatter issue, probabilistic models were introduced. All ligament rupture and burst pressures of U-bends were bounded by 90% lower limits of the probabilistic models for straight tubes. It was concluded that the prediction models for straight tubes could be applied to U-bends to conservatively evaluate the ligament rupture and burst pressures of U-bends with axial flaws.

Ligament rupture and unstable burst behaviors of axial flaws in steam generator U-bends

International Nuclear Information System (INIS)

Bahn, Chi Bum; Oh, Young-Jin; Majumdar, Saurin

2015-01-01

Highlights: • Ligament rupture and unstable burst pressure tests were conducted with U-bends. • In general, U-bends showed higher ligament rupture and burst pressures than straight tubes. • U-bend test data was bounded by 90% lower limit of the probabilistic models for straight tubes. • Prediction models for straight tubes could be conservatively applied to U-bends. - Abstract: Incidents of U-bend cracking in steam generator (SG) tubes have been reported, some of which have led to tube rupture. Experimental and analytical modeling efforts to determine the failure criteria of flawed SG U-bends are limited. To evaluate structural integrity of flawed U-bends, ligament rupture and unstable burst pressure tests were conducted on 57 and 152 mm bend radius U-bends with axial electrical discharge machining notches. In general, the ligament rupture and burst pressures of the U-bends were higher than those of straight tubes with similar notches. To quantitatively address the test data scatter issue, probabilistic models were introduced. All ligament rupture and burst pressures of U-bends were bounded by 90% lower limits of the probabilistic models for straight tubes. It was concluded that the prediction models for straight tubes could be applied to U-bends to conservatively evaluate the ligament rupture and burst pressures of U-bends with axial flaws.

Effects of mechanical properties and geometric conditions on stiffness of Hyperboloid Shallow Shell

Directory of Open Access Journals (Sweden)

Zhao Lihong

2015-01-01

Full Text Available The experiment models based on the hyperboloid shallow shells that represent automobile panel's surface features are established. The effects of material properties and geometric conditions condition on the stiffness of hyperboloid shallow shell are investigated experimentally. The influences of panel thickness and geometric conditions on stiffness are very obvious. Stiffness increases with increasing of the panel thickness, and stiffness doubled as increasing in thickness with 0.1 mm. The effect of thickness on stiffness is far greater than that of blank holding force. The greater the arc height of punch, the greater the stiffness. And stiffness increases nearly by five times with arc height of punch is from 3mm to 9mm. The effect of arc height of punch on stiffness is far greater than that of materials mechanical properties. The stiffness is varied with different panel material properties by the same forming and stiffness test conditions. The decrease of yield strength is beneficial to the panel stiffness. The appropriate choice of materials and forming process condition is important in meeting necessary requirements for the energy-saving, lightweight and reducing wind resistance design in automotive industry.

The effect of cracks on the limit load of pipe bends under in-plane bending

International Nuclear Information System (INIS)

Griffiths, J.E.

1976-06-01

The limit analysis of the in-plane bending of curved tubes had received attention previously, but the effect of defects in the tube has not been considered. A lower bound has been established which, with no defects present, is in agreement with previous theoretical work. The method of linear programming allows cracks to be introduced into analysis, and results have been obtained for various geometries of defect. The results show that the presence of cracks in the pipe bend can have a marked effect on the theoretical limit load: a part-through crack penetrating only half the wall thickness will reduce the limit moment by up to 10%. The worst possible case of a through-crack may reduce the limit load by 60%. (author)

The effect of cracks on the limit load of pipe bends under in-plane bending

International Nuclear Information System (INIS)

Griffiths, J.E.

1976-06-01

The limit analysis of the in-plane bending of curved tubes had received attention previously, but the effect of defects in the tube has not been considered. A lower bound is established, which, with no defects present, is in agreement with previous theoretical work. The method of linear programming allows cracks to be introduced into the analysis. and results have been obtained for various geometries of defect. The results show that the presence of cracks in the pipe bend can have a marked effect on the theoretical limit load: a part-through crack penetrating only half the wall thickness will reduce the limit moment by up to 10%. The worst possible case of a through-crack may reduce the limit load by 60% (author)

Intraventricular filling under increasing left ventricular wall stiffness and heart rates

Science.gov (United States)

Samaee, Milad; Lai, Hong Kuan; Schovanec, Joseph; Santhanakrishnan, Arvind; Nagueh, Sherif

2015-11-01

Heart failure with normal ejection fraction (HFNEF) is a clinical syndrome that is prevalent in over 50% of heart failure patients. HFNEF patients show increased left ventricle (LV) wall stiffness and clinical diagnosis is difficult using ejection fraction (EF) measurements. We hypothesized that filling vortex circulation strength would decrease with increasing LV stiffness irrespective of heart rate (HR). 2D PIV and hemodynamic measurements were acquired on LV physical models of varying wall stiffness under resting and exercise HRs. The LV models were comparatively tested in an in vitro flow circuit consisting of a two-element Windkessel model driven by a piston pump. The stiffer LV models were tested in comparison with the least stiff baseline model without changing pump amplitude, circuit compliance and resistance. Increasing stiffness at resting HR resulted in diminishing cardiac output without lowering EF below 50% as in HFNEF. Increasing HR to 110 bpm in addition to stiffness resulted in lowering EF to less than 50%. The circulation strength of the intraventricular filling vortex diminished with increasing stiffness and HR. The results suggest that filling vortex circulation strength could be potentially used as a surrogate measure of LV stiffness. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

Dynamic Stiffness Transfer Function of an Electromechanical Actuator Using System Identification

Science.gov (United States)

Kim, Sang Hwa; Tahk, Min-Jea

2018-04-01

In the aeroelastic analysis of flight vehicles with electromechanical actuators (EMAs), an accurate prediction of flutter requires dynamic stiffness characteristics of the EMA. The dynamic stiffness transfer function of the EMA with brushless direct current (BLDC) motor can be obtained by conducting complicated mathematical calculations of control algorithms and mechanical/electrical nonlinearities using linearization techniques. Thus, system identification approaches using experimental data, as an alternative, have considerable advantages. However, the test setup for system identification is expensive and complex, and experimental procedures for data collection are time-consuming tasks. To obtain the dynamic stiffness transfer function, this paper proposes a linear system identification method that uses information obtained from a reliable dynamic stiffness model with a control algorithm and nonlinearities. The results of this study show that the system identification procedure is compact, and the transfer function is able to describe the dynamic stiffness characteristics of the EMA. In addition, to verify the validity of the system identification method, the simulation results of the dynamic stiffness transfer function and the dynamic stiffness model were compared with the experimental data for various external loads.

Arthroscopically assisted reconstruction of triangular fibrocartilage complex foveal avulsion in the ulnar variance-positive patient.

Science.gov (United States)

Kim, ByungSung; Yoon, Hong-Kee; Nho, Jae-Hwi; Park, Kang Hee; Park, Sung-Yong; Yoon, Jun-Hee; Song, Hyun Seok

2013-11-01

Our aim was to evaluate the clinical results of patients treated by arthroscopically assisted reconstruction of foveal avulsion injury of the triangular fibrocartilage complex (TFCC) using a suture anchor. We retrospectively reviewed the results of 15 patients (11 men and 4 women; mean age, 30.5 years) who underwent surgical procedures for the treatment of TFCC foveal avulsion at our hospital. The patients were followed up for a mean of 29 months. The patients had TFCC foveal avulsion caused by sprains (n = 8), falls (n = 4), playing baseball (n = 2), and a motor vehicle accident (n = 1). All the patients underwent magnetic resonance imaging. Radiographs obtained to assess ulnar variance (UV), ulnar-dorsal subluxation, and function of the wrist based on grip power; Disabilities of the Arm, Shoulder and Hand score; and Mayo wrist score were examined for all patients both preoperatively and postoperatively. On preoperative magnetic resonance imaging, TFCC foveal avulsion was observed in 13 of 15 cases. The mean UV value based on preoperative simple radiographic findings was 1.7 ± 1.0 mm, and dorsal subluxation at the distal ulna improved from 2.9 ± 3.0 mm to 0.2 ± 0.9 mm (P = .017). In all cases the distal radioulnar joint instability disappeared postoperatively. Grip power (compared with the uninvolved limb) was 79.3% preoperatively and 82.9% postoperatively (P = .086). The Disabilities of the Arm, Shoulder and Hand scores were 28.4 points preoperatively and 16.6 points postoperatively (P = .061). The Mayo wrist scores were excellent in 10 cases, good in 2, and fair in 3, and the mean score improved significantly from 64 points preoperatively to 84 points postoperatively (P = .007). Arthroscopic-assisted suture anchor reattachment of the TFCC in patients with traumatic TFCC foveal avulsion can prevent or reduce distal radioulnar joint instability and reduce pain even in chronic cases with positive UV. Level IV, therapeutic case series. Copyright © 2013

Martial arts training attenuates arterial stiffness in middle aged adults.

Science.gov (United States)

Douris, Peter C; Ingenito, Teresa; Piccirillo, Barbara; Herbst, Meredith; Petrizzo, John; Cherian, Vincen; McCutchan, Christopher; Burke, Caitlin; Stamatinos, George; Jung, Min-Kyung

2013-09-01

Arterial stiffness increases with age and is related to an increased risk of coronary artery disease. Poor trunk flexibility has been shown to be associated with arterial stiffness in middle-aged subjects. The purpose of our research study was to measure arterial stiffness and flexibility in healthy middle-aged martial artists compared to age and gender matched healthy sedentary controls. Ten martial artists (54.0 ± 2.0 years), who practice Soo Bahk Do (SBD), a Korean martial art, and ten sedentary subjects (54.7 ± 1.8 years) for a total of twenty subjects took part in this cross-sectional study. Arterial stiffness was assessed in all subjects using pulse wave velocity (PWV), a recognized index of arterial stiffness. Flexibility of the trunk and hamstring were also measured. The independent variables were the martial artists and matched sedentary controls. The dependent variables were PWV and flexibility. There were significant differences, between the SBD practitioners and sedentary controls, in PWV (P = 0.004), in trunk flexibility (P= 0.002), and in hamstring length (P= 0.003). The middle-aged martial artists were more flexible in their trunk and hamstrings and had less arterial stiffness compared to the healthy sedentary controls. The flexibility component of martial art training or flexibility exercises in general may be considered as a possible intervention to reduce the effects of aging on arterial stiffness.

Gender differences in variability patterns of forward bending