3,580 research outputs found
The Variational Problems and Equivalent Forms for a Second Order Elliptic Boundary Value Problem
AbstractWe consider the variational problems for second order elliptic boundary value problems and find the equivalent forms
Error estimates for discontinuous Galerkin method for nonlinear parabolic equations
AbstractWe consider the nonlinear parabolic partial differential equations. We construct a discontinuous Galerkin approximation using a penalty term and obtain an optimal L∞(L2) error estimate
Evaluation of constitutive models for springback prediction in U-draw/bending of DP and TRIP steel sheets
U-draw/bending experiments and simulations were performed to investigate the characteristics of springback in sheet metals. The finite element method is frequently used for the simulation of springback, but the predictions are strongly influenced by the constitutive models such as yield criteria and hardening laws. In the present study, springback of DP and TRIP steel sheets after U-draw/bending was predicted with a finite element analysis. Various yield functions were considered, namely, the isotropic von Mises and anisotropic Hill models. For strain hardening, isotropic, non-linear kinematic and combined isotropic-kinematic hardening models were considered. In order to characterize the isotropic hardening behavior, both uniaxial and balanced biaxial (hydraulic bulge) tension tests were carried out. For the characterization of the combined isotropic-kinematic hardening model, forward-reverse simple shear tests were conducted. The springback predictions were greatly influenced by the choice of the hardening model but slightly affected by the choice of the yield criterion. The kinematic hardening and combined isotropic-kinematic hardening models provided satisfactory predictions for DP590 and TRIP590 sheets, respectively. Due to an extended measurable strain range, the use of the flow curves from the hydraulic bulge test led to more reliable results than those of uniaxial tension.ope
Simple and scalable growth of AgCl nanorods by plasma-assisted strain relaxation on flexible polymer substrates
Implementing nanostructures on plastic film is indispensable for highly efficient flexible optoelectronic devices. However, due to the thermal and chemical fragility of plastic, nanostructuring approaches are limited to indirect transfer with low throughput. Here, we fabricate single-crystal AgCl nanorods by using a Cl 2 plasma on Ag-coated polyimide. Cl radicals react with Ag to form AgCl nanorods. The AgCl is subjected to compressive strain at its interface with the Ag film because of the larger lattice constant of AgCl compared to Ag. To minimize strain energy, the AgCl nanorods grow in the [200] direction. The epitaxial relationship between AgCl (200) and Ag (111) induces a strain, which leads to a strain gradient at the periphery of AgCl nanorods. The gradient causes a strain-induced diffusion of Ag atoms to accelerate the nanorod growth. Nanorods grown for 45 s exhibit superior haze up to 100% and luminance of optical device increased by up to 33%. ? The Author(s) 2017.114Ysciescopu
Nano encapsulation of Drug-loaded Lipid by Temperature induced Phase Transition
Pluronic nanoparticles (NPs) were prepared by means of a temperature-induced phase transition in the mixture composed of Pluronic F-68 and liquid Tween 80/soybean oil containing model drugs such as orlistat, caffeine, and ibuprofen sodium salt. Liquid
soybean oil/Tween 80 was used as a solubilizer for model drugs, and Pluronic F-68 was the polymer that stabilizes liquid soybean oil/Tween 80 containing model drugs. Field-emission scanning electron microscopy and particle size analyzer were used
to observe the morphology and size distribution of the prepared NPs. X-ray diffractometer was used to understand relationship between the crystalline state of the model drug and its solubility in the aqueous media. To observe the feasibility of Pluronic NPs as a
drug delivery system, the release pattern of model drugs was observed
THE EFFECTS OF CORE STABILITY TRAINING ON THE FUNCTIONAL MOVEMENT SCREEN AND POSTURAL STABILITY IN COLLEGIATE STUDENTS
This study evaluated effects of core stability training (CST) on the functional movement screen (FMS) and postural stability (PS) in healthy young collegiate students. 28 healthy collegiate female students were assigned to an experimental (CST exercises twice a week for six weeks) or control group (equal time of warm-up and stretching exercises only). The CST combined Pilates and Swiss ball exercise for fifty minutes, twice per week, for six weeks. FMS scores were evaluated by a certified professional. The PS was evaluated by the 8-direction limits of stability (LOS) test using the Biodex Balance System. Repeated measures analyses of variance (ANOVAs) revealed the FMS and LOS performances in the experiment group were significantly improved after training. It was concluded that regular CST can improve the performance of FMS and dynamic postural stability in healthy young students
THE EFFECTS OF UNSTABLE EXERCISE TRAINING ON DYNAMIC BALANCE AND ABDOMINAL MUSCLE STRENGTH IN YOUNG FEMALE INDIVIDUALS
The purpose of this study was to evaluate the effects of unstable exercise training (UET) on dynamic balance (DB) and abdominal muscle strength in young female individuals. 22 healthy collegiate female students underwent a series of UET sessions. DB was evaluated by the 8-direction limits of stability (LOS) test. Abdominal strength was measured using 60s sit-up test. The UET combined the Both Sides Utilized (BOSU) and Swiss ball exercises, undertaken for 90mins, twice per week, for 6 weeks. The LOS performance in overall, forward, right, forward-left, backward-right, and backward-left at level 6 also significantly improved post-training. Further, significant improvements were observed in the 60s sit-up test. It is concluded that regular UET can improve DB and abdominal muscle strength in young female individuals
THE EFFECTS OF NEUROMUSCULAR TRAINING ON COUNTER-MOVEMENT JUMP PERFORMANCE IN HEALTHY YOUNG STUDENTS
Neuromuscular training (NT) programs are effective for improving measures of performance and used by athletes in all types of sports to increase sports performance. The purpose of this study was to evaluate the effects of NT on arm counter-movement jump (CMJ) performance in healthy young students. Thirteen healthy collegiate female students volunteered and underwent a series of NT exercise. The NT was performed for 50 minutes three times per week, for six weeks. Paired t-tests were used to analyze the differences in each parameter before and after training. The arm CMJ in explosive power, flight time, and jump height was statistically improved in post-training compared to pretraining. It is concluded that six weeks NT can improve the arm CMJ performance in young female students
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