Sculpting the band gap: a computational approach

Materials with optimized band gap are needed in many specialized applications. In this work, we demonstrate that Hellmann-Feynman forces associated with the gap states can be used to find atomic coordinates with a desired electronic density of states. Using tight-binding models, we show that this approach can be used to arrive at electronically designed models of amorphous silicon and carbon. We provide a simple recipe to include a priori electronic information in the formation of computer models of materials, and prove that this information may have profound structural consequences. An additional example of a graphene nanoribbon is provided to demonstrate the applicability of this approach to engineer 2-dimensional materials. The models are validated with plane-wave density functional calculations.Comment: Submitted to Physical Review Letters on June 12, 201

Atomistic Simulations of Flash Memory Materials Based on Chalcogenide Glasses

In this chapter, by using ab-initio molecular dynamics, we introduce the latest simulation results on two materials for flash memory devices: Ge2Sb2Te5 and Ge-Se-Cu-Ag. This chapter is a review of our previous work including some of our published figures and text in Cai et al. (2010) and Prasai & Drabold (2011) and also includes several new results.Comment: 24 pages, 20 figures. This is a chapter submitted for the book under the working title "Flash Memory" (to be published by Intech ISBN 978-953-307-272-2

Implementing Culture-Centered Diabetes Self-Management for the South Asian Population

Type 2 diabetes is a chronic metabolic disorder that requires complex care and involves a variety of self-management decisions on a regular basis to manage the symptoms and avoid complications. The prevalence of type 2 diabetes among the South Asian population is six times higher than their European and white American counterparts (Gujral et al. 2013). Culturally sensitive education may be the key to overcoming the barriers related to standard diabetes patient education and culturally appropriate type 2 diabetes management. Research and evidence-based practices show Diabetes Self-Management Education (DSME) is associated with significant improvements in glycemic control and overall better health outcomes. Understanding the hurdles of educating patients is key in implementing effective education among diverse communities. The goal of this manuscript is to identify the effectiveness of culturally appropriate diabetes self-care education that improves the quality outcomes among the South Asian population in America

Performance evaluation of lentil and chickpea genotypes in Doti district of Nepal

Lentil and chickpea are important winter legumes of Nepal. The experiments were carried out to evaluate the agronomic performance of lentil and chickpea genotypes at research field of Regional Agricultural Research Station (RARS), Bhagetada, Doti, Nepal during winter seasons of 2012 and 2013. The 16 lentil genotypes were evaluated in both years whereas 20 and 14 genotypes of chickpea were evaluated in 2012 and 2013 respectively. The genotypes were evaluated in a randomized complete block design with three replications. The results showed that both lentil and chickpea genotypes indicated differences for their morphological traits namely plant height, flowering, maturity, pods/plant and grain yield. The combined analysis of trials over years showed that lentil genotype namely Black Masuro produced the highest grain yield (790 kg/ha) followed by LG 12 (746 kg/ha) and ILL 3111 (747 kg/ha), respectively. Similarly, chickpea genotypes namely ICCX 840508-31 produced the highest grain yield (953 kg/ha) followed by ICCX 840508-40 (911 kg/ha) and BG 372 (850 kg/ha), respectively. It is suggested that the superior genotypes derived from these experiments could be further evaluated in farmers’ fields  before making recommendation for general cultivatio

Structural origins of electronic conduction in amorphous copper-doped alumina

We perform an {\it ab initio} modeling of amorphous copper-doped alumina (a-Al$_2$O$_3$:Cu), a prospective memory material based on resistance switching, and study the structural origin of electronic conduction in this material. We generate molecular dynamics based models of a-Al$_2$O$_3$:Cu at various Cu-concentrations and study the structural, electronic and vibrational properties as a function of Cu-concentration. Cu atoms show a strong tendency to cluster in the alumina host, and metallize the system by filling the band gap uniformly for higher Cu-concentrations. We also study thermal fluctuations of the HOMO-LUMO energy splitting and observe the time evolution of the size of the band gap, which can be expected to have an important impact on the conductivity. We perform a numerical computation of conduction pathways, and show its explicit dependence on Cu connectivity in the host. We present an analysis of ion dynamics and structural aspects of localization of classical normal modes in our models

An assessment of the potential impacts of dietary norms in food consumption structure and expenditure in Nepal

This paper attempts to assess the potential impacts of the adoption of nutritional norms on the consumption structure and expenditure. In other words, what would happen to food consumption structure and expenditure if population changes from their actual food consumption pattern to one that meets nutritional recommendations as defined by WHO

Reflections on researching women’s economic empowerment in post-earthquake Kathmandu

The earthquake and aftershocks that hit Nepal in April-May 2015 had a devastating impact on the Kathmandu Valley. National and international donors responded with both cash and material assistance, but there has been relatively little research into aid effectiveness. Here Srijana Nepal, Neha Uprety and Apekshya Prasai discuss their recent fieldwork exploring the gendered outcomes of cash transfers and the challenges that arose conducting qualitative research in earthquake-affected communities

Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu2_2OSeO3_3

We report on the observation of magnon thermal conductivity $\kappa_m\sim$ 70 W/mK near 5 K in the helimagnetic insulator Cu$_2$OSeO$_3$, exceeding that measured in any other ferromagnet by almost two orders of magnitude. Ballistic, boundary-limited transport for both magnons and phonons is established below 1 K, and Poiseuille flow of magnons is proposed to explain a magnon mean-free path substantially exceeding the specimen width for the least defective specimens in the range 2 K $<T<$ 10 K. These observations establish Cu$_2$OSeO$_3$ as a model system for studying long-wavelength magnon dynamics.Comment: 10pp, 9 figures, accepted PRB (Editor's Suggestion