Absorption enhancement in InGaN-based photonic crystal-implemented solar cells

Cataloged from PDF version of article.We investigate the absorption characteristics of InGaN solar cells with high indium (0.8) content and a one-dimensional periodic nano-scale pattern (implemented) in the InGaN layer theoretically. The short-circuit current of our InGaN-based solar cell structure is calculated for different lattice constant, etch depth, and fill factor values. A substantial increase in the absorption (17.5% increase in short-circuit current) is achieved when the photonic crystal pattern is thoroughly optimized. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JNP.6.061603

3D thumbnails for mobile media browser interface with autostereoscopic displays

In this paper, we focus on the problem of how to visualize and browse 3D videos and 3D images in a media browser application, running on a 3D-enabled mobile device with an autostereoscopic display. We propose a 3D thumbnail representation format and an algorithm for automatic 3D thumbnail generation from a 3D video + depth content. Then, we present different 3D user interface layout schemes for 3D thumbnails, and discuss these layouts with the focus on their usability and ergonomics. © 2010 Springer-Verlag Berlin Heidelberg

YOUNG ADOLESCENT EFL LEARNERS’ PERSPECTIVES ON CRITICAL THINKING SKILLS

Critical Thinking Skills (CTs) are among the 21st century learning skills, and schools are expected to equip the students with these skills.  Turkey has been restructuring the educational system in order to improve the quality of education which enables students to acquire such learning skills as critical and creative thinking, problem solving, and collaboration. The present study based on the perspectives of Young Adolescent EFF learners presents findings on the students’ awareness of CTs, and whether or not they apply them to a given task, and if there is any conflict between knowledge and application of CTs. The findings showed that the students, despite their quiet well awareness, they did not effectively apply CTs. The problems they encountered were assumed to be resulted from lacking in metacognitive knowledge

Re-annotation and re-analysis of the Campylobacter jejuni NCTC11168 genome sequence

BACKGROUND: Campylobacter jejuni is the leading bacterial cause of human gastroenteritis in the developed world. To improve our understanding of this important human pathogen, the C. jejuni NCTC11168 genome was sequenced and published in 2000. The original annotation was a milestone in Campylobacter research, but is outdated. We now describe the complete re-annotation and re-analysis of the C. jejuni NCTC11168 genome using current database information, novel tools and annotation techniques not used during the original annotation. RESULTS: Re-annotation was carried out using sequence database searches such as FASTA, along with programs such as TMHMM for additional support. The re-annotation also utilises sequence data from additional Campylobacter strains and species not available during the original annotation. Re-annotation was accompanied by a full literature search that was incorporated into the updated EMBL file [EMBL: AL111168]. The C. jejuni NCTC11168 re-annotation reduced the total number of coding sequences from 1654 to 1643, of which 90.0% have additional information regarding the identification of new motifs and/or relevant literature. Re-annotation has led to 18.2% of coding sequence product functions being revised. CONCLUSIONS: Major updates were made to genes involved in the biosynthesis of important surface structures such as lipooligosaccharide, capsule and both O- and N-linked glycosylation. This re-annotation will be a key resource for Campylobacter research and will also provide a prototype for the re-annotation and re-interpretation of other bacterial genomes

Design and analysis of advanced nonoverlapping winding induction machines for EV/HEV applications

This paper presents a detailed analysis and design guidelines for advanced nonoverlapping winding induction machines (AIMs) with coil-pitch of two slot-pitches by considering some vital empirical rules and flux-weakening characteristics. The aim of the study is to develop a type of new winding and stator topology for induction machines (IMs) that will lead to a decrease in total axial length without sacrificing torque, power, and efficiency. The key performance characteristics of the improved AIMs are investigated by 2D time-stepping finite element analysis (FEA) and compared with those of IMs having fractional and conventional overlapping and nonoverlapping windings. Compared with the conventional overlapping winding counterpart of the AIM, a ~25% shorter axial length without sacrificing torque, output power, and efficiency is achieved. In addition, the influences of major design parameters, such as stator slot, rotor slot and pole numbers, stack length, number of turns per phase, machine geometric parameters, etc., on the flux-weakening characteristics are investigated. It has been concluded that the major design parameters have a considerable effect on the electromagnetic performance. However, among those parameters, the influences of pole number and stack length together with the number of turns on flux-weakening characteristics are significant

The Campylobacter jejuni MarR-like transcriptional regulators RrpA and RrpB both influence bacterial responses to oxidative and aerobic stresses.

The ability of the human intestinal pathogen Campylobacter jejuni to respond to oxidative stress is central to bacterial survival both in vivo during infection and in the environment. Re-annotation of the C. jejuni NCTC11168 genome revealed the presence of two MarR-type transcriptional regulators Cj1546 and Cj1556, originally annotated as hypothetical proteins, which we have designated RrpA and RrpB (regulator of response to peroxide) respectively. Previously we demonstrated a role for RrpB in both oxidative and aerobic (O2) stress and that RrpB was a DNA binding protein with auto-regulatory activity, typical of MarR-type transcriptional regulators. In this study, we show that RrpA is also a DNA binding protein and that a rrpA mutant in strain 11168H exhibits increased sensitivity to hydrogen peroxide oxidative stress. Mutation of either rrpA or rrpB reduces catalase (KatA) expression. However, a rrpAB double mutant exhibits higher levels of resistance to hydrogen peroxide oxidative stress, with levels of KatA expression similar to the wild-type strain. Mutation of either rrpA or rrpB also results in a reduction in the level of katA expression, but this reduction was not observed in the rrpAB double mutant. Neither the rrpA nor rrpB mutant exhibits any significant difference in sensitivity to either cumene hydroperoxide or menadione oxidative stresses, but both mutants exhibit a reduced ability to survive aerobic (O2) stress, enhanced biofilm formation and reduced virulence in the Galleria mellonella infection model. The rrpAB double mutant exhibits wild-type levels of biofilm formation and wild-type levels of virulence in the G mellonella infection model. Together these data indicate a role for both RrpA and RrpB in the C. jejuni peroxide oxidative and aerobic (O2) stress responses, enhancing bacterial survival in vivo and in the environment

Sparse representation of two- and three-dimensional images with fractional Fourier, Hartley, linear canonical, and Haar wavelet transforms

Sparse recovery aims to reconstruct signals that are sparse in a linear transform domain from a heavily underdetermined set of measurements. The success of sparse recovery relies critically on the knowledge of transform domains that give compressible representations of the signal of interest. Here we consider two- and three-dimensional images, and investigate various multi-dimensional transforms in terms of the compressibility of the resultant coefficients. Specifically, we compare the fractional Fourier (FRT) and linear canonical transforms (LCT), which are generalized versions of the Fourier transform (FT), as well as Hartley and simplified fractional Hartley transforms, which differ from corresponding Fourier transforms in that they produce real outputs for real inputs. We also examine a cascade approach to improve transform-domain sparsity, where the Haar wavelet transform is applied following an initial Hartley transform. To compare the various methods, images are recovered from a subset of coefficients in the respective transform domains. The number of coefficients that are retained in the subset are varied systematically to examine the level of signal sparsity in each transform domain. Recovery performance is assessed via the structural similarity index (SSIM) and mean squared error (MSE) in reference to original images. Our analyses show that FRT and LCT transform yield the most sparse representations among the tested transforms as dictated by the improved quality of the recovered images. Furthermore, the cascade approach improves transform-domain sparsity among techniques applied on small image patches. © 2017 Elsevier Lt

Scheduling of grid tied battery energy storage system participating in frequency response services and energy arbitrage

Battery energy storage systems (BESS) are widely used to smooth power fluctuations and maintain the voltage and frequency of the power feeder at a desired level. T he National Grid Electricity Transmission (NGET), the primary electricity transmission network operator in the UK, has introduced various frequency response servic es that are designed to provide a real - time response to deviations in the grid frequency. In this study , a control algorithm is developed which generates a charge/discharge power output with respect to deviations in the grid frequency and the requisite service specifications. Using historical UK electricity prices, a new balancing service scheduling approach has also been developed to maximize energy arbitrage revenue by layering different types of balancing services throughout the day . Simulation result s show that the proposed algorithm delivers both dynamic and non - dynamic firm frequency response (FFR) and also enhanced frequency response (EFR) to NGET specifications while generating arbitrage revenue as well as service availability payment s in the balancing market. A comparative study is also presented to compare the yearly arbitrage revenue obtained from the work presented in this paper and a previous reference study . Finall y, exper imental results of a grid - tied 2MW /1MWh BESS have been used for verification purposes