In search of Robbins stability

We speculate on whether a certain p-adic stability phenomenon, observed by David Robbins empirically for Dodgson condensation, appears in other nonlinear recurrence relations that "unexpectedly" produce integer or nearly-integer sequences. We exhibit an example (number friezes) where this phenomenon provably occurs.Comment: 10 pages; to appear in the David Robbins memorial issue of Advances in Applied Mathematic

Structural, optical and nanomechanical properties of (1 1 1) oriented nanocrystalline ZnTe thin films

Structural, optical and nanomechanical properties of nanocrystalline Zinc Telluride (ZnTe) films of thickness upto 10 microns deposited at room temperature on borosilicate glass substrates are reported. X-ray diffraction patterns reveal that the films were preferentially oriented along the (1 1 1) direction. The maximum refractive index of the films was 2.74 at a wavelength of 2000 nm. The optical band gap showed strong thickness dependence. The average film hardness and Young’s modulus obtained from loaddisplacement curves and analyzed by Oliver-Pharr method were 4 and 70 GPa respectively. Hardness of (1 1 1) oriented ZnTe thin films exhibited almost 5 times higher value than bulk. The studies show clearly that the hardness increases with decreasing indentation size, for indents between 30 and 300 nm in depth indicating the existence of indentation size effect. The coefficient of friction for these films as obtained from the nanoscratch test was ∼0.4.Financial support in the form of fellowships to MSRNK and SK from the ACRHEM project of DRDO is acknowledged

Influence of organization ethos on research competence of teachers in higher education institutions

The standards of research depend on the maintenance and coordination of research activities that are conducted by the teachers in higher education institutions. The flexibility in ordinances and statutes empowers the higher education institutions to frame the guidelines that empower the research competence of the teachers. This descriptive research has collected the data from 451 regular teachers of higher education institutions from different areas of discipline for the research. The results of the study show that there is a significant difference in measures of the perceptions of the teachers towards the relationship between organization ethos and research competence in higher education institutions. The study indicates the practical and academic importance for teachers to enhance research performance of higher education institutions

Tool handle design for power GRIP

The use of tools is still widely appreciated in industries at various levels. The range of their application varies from a simple task like hammering to a complicated, complex and precision-demanding tasks such as that of surgical scalpels. Hence, it becomes highly essential to design the tool for ‘comfort’ from the perspective of user. The aim of this study is to design a tool handle for a task involving a simple power grip such as hammer. The focus of this study is mainly confined to identify the right cross-section and profile of the tool handle, based on subjective experimentation of a group of subjects and find the approximate dimension and shape(of both cross-section and profile) which outstands in subject’s perception of comfort. In this study, a new criteria for decision making has been employed during a brief subjective analysis to find out the better cross- section shape among the various possible shapes for the handle. The shape of the profile has been reverse engineered from an existing tool handle using a CAD software which was been rated high in market. At various turns during this study, new simplified approaches were used to accomplish certain tasks which can be considered as reasonable approximation to standard methods. The final step is to evaluate the design which has been perceived most comfortable by the subjects, using a subjective analysis through hand-mapping of discomfort

Implicit self-consistent electrolyte model in plane-wave density-functional theory

The ab-initio computational treatment of electrochemical systems requires an appropriate treatment of the solid/liquid interfaces. A fully quantum mechanical treatment of the interface is computationally demanding due to the large number of degrees of freedom involved. In this work, we describe a computationally efficient model where the electrode part of the interface is described at the density-functional theory (DFT) level, and the electrolyte part is represented through an implicit solvation model based on the Poisson-Boltzmann equation. We describe the implementation of the linearized Poisson-Boltzmann equation into the Vienna Ab-initio Simulation Package (VASP), a widely used DFT code, followed by validation and benchmarking of the method. To demonstrate the utility of the implicit electrolyte model, we apply it to study the surface energy of Cu crystal facets in an aqueous electrolyte as a function of applied electric potential. We show that the applied potential enables the control of the shape of nanocrystals from an octahedral to a truncated octahedral morphology with increasing potential

Advanced Magnetic Resonance Imaging in Glioblastoma: A Review

INTRODUCTION In 2017, it is estimated that 26,070 patients will be diagnosed with a malignant primary brain tumor in the United States, with more than half having the diagnosis of glioblas- toma (GBM).1 Magnetic resonance imaging (MRI) is a widely utilized examination in the diagnosis and post-treatment management of patients with glioblastoma; standard modalities available from any clinical MRI scanner, including T1, T2, T2-FLAIR, and T1-contrast-enhanced (T1CE) sequences, provide critical clinical information. In the last decade, advanced imaging modalities are increasingly utilized to further charac- terize glioblastomas. These include multi-parametric MRI sequences, such as dynamic contrast enhancement (DCE), dynamic susceptibility contrast (DSC), diffusion tensor imaging (DTI), functional imaging, and spectroscopy (MRS), to further characterize glioblastomas, and significant efforts are ongoing to implement these advanced imaging modalities into improved clinical workflows and personalized therapy approaches. A contemporary review of standard and advanced MR imaging in clinical neuro-oncologic practice is presented