Defect-unbinding transitions and inherent structures in two dimensions

We present a large-scale (36000-particle) computational study of the "inherent structures" (IS) associated with equilibrium, two-dimensional, one-component Lennard-Jones systems. Our results provide strong support both for the inherent-structures theory of classical fluids, and for the KTHNY theory of two-stage melting in two dimensions. This support comes from the observation of three qualitatively distinct "phases" of inherent structures: a crystal, a "hexatic glass", and a "liquid glass". We also directly observe, in the IS, analogs of the two defect-unbinding transitions (respectively, of dislocations, and disclinations) believed to mediate the two equilibrium phase transitions. Each transition shows up in the inherent structures---although the free disclinations in the "liquid glass" are embedded in a percolating network of grain boundaries. The bond-orientational correlation functions of the inherent structures show the same progressive loss of order as do the three equilibrium phases: long-range to quasi-long-range to short-range.Comment: RevTeX, 8 pages, 15 figure

Optimization and Analysis of Underactuated Linkage Robotic Finger

In this study it is required to maximize the transmission performance, which is leading to increase the transmitted torque from the actuated joints to the underactuated joints through transmission mechanism. Accordingly grasping forces in finger phalanges will increase. Studying the four bar mechanism parameters of a specific configuration within defined limits led to the linkage transmission defect parameter, which play a major role in deciding the linkage performance, used as optimization objective function to be minimized. This study presents an optimization procedure carried out using matlab fminunc function, formulated by using Freudenstein's equations to be applied on a (Cassino-Underactuated-Multifinger-Hand) design , using  one finger and a thumb .A mathematical model of grasping forces of the finger were introduced taking into account the solid links in the( Ca.U.M.Ha)  robotic finger . Keywords: Linkage , underactuated, optimizatio

A Review of Lower Limb Exoskeletons

In general, exoskeletons are defined as wearable robotic mechanisms for providing mobility. In the last six decades, many research work have been achieved to enhance the performance of exoskeletons thus developing them to nearly commercialized products. In this paper, a review is made for the lower limb exoskeleton concerning history, classification, selection and development, also a discussion for the most important aspects of comparison between different designs is presented. Further, some concluding remarks are withdrawn which could be useful for future work. Keywords: Exoskeletons, Lower extremity exoskeleton, Wearable robot

Contact mechanics for soft robotic fingers: modeling and experimentation

Human fingers possess mechanical characteristics, which enable them to manipulate objects. In robotics, the study of soft fingertip materials for manipulation has been going on for a while; however, almost all previous researches have been carried on hemispherical shapes whereas this study concentrates on the use of hemicylindrical shapes. These shapes were found to be more resistant to elastic deformations for the same materials. The purpose of this work is to generate a modified nonlinear contact-mechanics theory for modeling soft fingertips, which is proposed as a power-law equation. The contact area of a hemicylindrical soft fingertip is proportional to the normal force raised to the power of γcy, which ranges from 0 to 1/2. Subsuming the Timoshenko and Goodier (S. P. Timoshenko and J. N. Goodier, Theory of Elasticity, 3rd ed. (McGraw-Hill, New York, 1970) pp. 414-420) linear contact theory for cylinders confirms the proposed power equation. We applied a weighted least-squares curve fitting to analyze the experimental data for different types of silicone (RTV 23, RTV 1701, and RTV 240). Our experimental results supported the proposed theoretical prediction. Results for human fingers and hemispherical soft fingers were also compare

Position Control of Linkage Underactuated Robotic Hand

In this study a proposed PID control system for (Ca.U.M.Ha) robotic hand with a finger and a thumb introduced, to control grasping cylindrical objects made from different materials soft and hard within a range of (48-150) mm in diameter . A samples of PID response figures for object that need just a finger, and object that needs a finger with a thumb introduced in additional to the figures of actuators voltage needed for both cases through grasping. Keywords: Linkage , underactuated, position  PID contro

Tissue factor as the main activator of the coagulation system during cardiopulmonary bypass

AbstractObjective: This study investigates the influence of foreign material and blood aspirated from nonvascular structures on activation of coagulation, hemolysis, and blood loss. Methods: The series comprises 3 randomized groups (groups C, S, and S+P) of 10 patients undergoing routine coronary artery bypass grafting with cardiopulmonary bypass. In group C, the control group, all aspirated blood was returned into the circulation. In group S suction blood was discarded, whereas group S+P was identical to group S, with surfaces coated with phosphorylcholine. Plasma concentrations of β-thromboglobulin, thrombin generation, haptoglobin, and free hemoglobin, as well as blood loss, were measured. Results: A steady increase in free plasma hemoglobin, as well as an increased generation of thrombin, was noticed in group C. Moreover, a close correlation (r = 0.916) between the generation of thrombin and its inhibition (thrombin-antithrombin complexes) was observed. Platelets were clearly activated in group C and, to a lesser extent, in group S. In contrast, platelet activation in group S+P was negligible, resulting in a 30% decrease in blood loss (P = .05). Conclusions: Aspirated blood contaminated by tissue contact is the most important activator of the coagulation system and the principal cause of hemolysis during cardiopulmonary bypass. Contact with a foreign surface is not a main variable in the procoagulant effect of bypass. Mimicking the outer cell membrane structure resulted in decreased platelet activation and decreased blood loss.J Thorac Cardiovasc Surg 2002;123:951-

Phase II study of fosaprepitant + 5HT3 receptor antagonist + dexamethasone in patients with germ cell tumors undergoing 5-day cisplatin-based chemotherapy: A Hoosier Cancer Research Network Study

Purpose A phase III study adding aprepitant to a 5HT3 receptor antagonist (5HT3-RA) plus dexamethasone in germ cell tumor (GCT) patients treated with 5-day cisplatin combination chemotherapy demonstrated a significant improvement in complete response (CR) (J Clin Onc 30:3998-4003, 2012). Fosaprepitant has demonstrated non-inferiority compared to aprepitant in single-day cisplatin chemotherapy and is approved as a single-dose alternative. This single-arm phase II study is the first clinical trial evaluating fosaprepitant in patients receiving multi-day cisplatin regimen. Methods GCT patients receiving a 5-day cisplatin combination chemotherapy were enrolled. Fosaprepitant 150 mg was given IV on days 3 and 5. A 5HT3-RA days 1–5 (days 1, 3, and 5, if palonosetron) plus dexamethasone 20 mg days 1 and 2 and 4 mg po bid days 6, 7, and 8 was administered. Rescue antiemetics were allowed. The primary objective was to determine the CR rate—no emetic episodes or use of rescue medications. Accrual of 64 patients was planned with expected CR > 27 %. Results Sixty-five patients were enrolled of whom 54 were eligible for analysis. Median age was 33. Fifty-one patients received bleomycin, etoposide, and cisplatin (BEP) chemotherapy. CR was observed in 13 (24.1 %) patients (95 % Agresti-Coull binomial C.I. 14.5 %, 37.1 %). Conclusion The data in this phase II study, in contrast to our prior phase III study, appears to indicate a lower CR rate with the substitution of fosaprepitant for aprepitant. It is unknown whether the substitution of fosaprepitant for aprepitant provides the same benefit in multi-day cisplatin that was achieved with single-day cisplatin

Universality in the Screening Cloud of Dislocations Surrounding a Disclination

A detailed analytical and numerical analysis for the dislocation cloud surrounding a disclination is presented. The analytical results show that the combined system behaves as a single disclination with an effective fractional charge which can be computed from the properties of the grain boundaries forming the dislocation cloud. Expressions are also given when the crystal is subjected to an external two-dimensional pressure. The analytical results are generalized to a scaling form for the energy which up to core energies is given by the Young modulus of the crystal times a universal function. The accuracy of the universality hypothesis is numerically checked to high accuracy. The numerical approach, based on a generalization from previous work by S. Seung and D.R. Nelson ({\em Phys. Rev A 38:1005 (1988)}), is interesting on its own and allows to compute the energy for an {\em arbitrary} distribution of defects, on an {\em arbitrary geometry} with an arbitrary elastic {\em energy} with very minor additional computational effort. Some implications for recent experimental, computational and theoretical work are also discussed.Comment: 35 pages, 21 eps file

Optimal Design of Three-Phalanx Prosthesis Underactuated Fingers Using Genetic Algorithm

This research is interested to investigate the optimum design procedure for a finger driving mechanism to have a proper configuration of the finger for its utilization in hand prosthesis. To get this goal, a Genetic Algorithm (G.A) was used. Three criteria were selected to find the optimal solution. The most important of them was the percentage of the grasping stability. This criterion was evaluated as must type by using Kepner-tregos method. When the optimal solution was found, this one was modified to facilitate the fabrication of a prototype. The modifications consist of mostly rounding the parameters and uniforming the rollers dimensions. Those changes did not affect too much the forces characteristics. The prosthetic hand prototype was built of hard ABS (Acrylonitrile Butadiene Styrene) plastic using rapid prototyping. Testing results indicate that the proposed Genetic Algorithm gives reasonable -quality results in short computation time