A direct borohydride-peroxide fuel cell-LiPO hybrid motorcycle prototype: Investigation of short-term behavior of DBPFC stack – I

In the present study, a safer and more performance 270?W Direct Borohydride/Peroxide Fuel Cell (DBPFC) Stack has been constructed for an electrical hybrid motorbike application. Performance tests were carried out with single cell and 5–10–25?cell stacks. Performance loss has been not observed while stacking DBPFC because of the Independent Cell Liquid Distribution Network (ICLDN) system and special bipolar plate design. The power densities have been approximately 120?mWcm^?2 for a single DBPFC and 25-cell DBPFC stack without any stacking loss. Additionally, the stack temperature has been controlled by keeping the oxidant concentration low, and it has been maintained at approximately 52?°C without using a cooling system. The short-term performances of the 25-cell DBPFC stack have been tested over 25?min and 50?min, which showed that the performance and stack security of the DBPFC are highly related to the oxidant properties, such as the concentration, temperature and feed type.     

Determination of the structural properties of a columnar hexagonal liquid crystal by light scattering

In this study we examine a new computer model of light scattering. Light propagation through a columnar hexagonal liquid crystal has been represented by using a cylindrical model. Numerical aspects of the light scattering process, which are based on numerically solving Maxwell's equations, have been calculated for a liquid crystal. We describe in detail the circular cylindrical model for computing light scattering from a columnar hexagonal liquid crystal and present the results of benchmark computations. We report results of extensive calculation for oriented columnar molecular systems. Our results are compared with previous studies on light scattering by other materials.     

Platelet‐to‐lymphocyte ratio better predicts inflammation than neutrophil‐to‐lymphocyte ratio in end‐stage renal disease patients

Neutrophil‐to‐lymphocyte ratio (NLR) was introduced as a potential marker to determine inflammation in end‐stage renal disease (ESRD) patients. Recently, platelet‐to‐lymphocyte ratio (PLR) and NLR were found to positively correlated with inflammatory markers including tumor necrosis factor‐α (TNF‐α) and interleukin (IL)‐6 in cardiac and noncardiac patients. Data regarding PLR and its association with inflammation are lacking in hemodialysis (HD) and peritoneal dialysis (PD) patients. Hence, we aimed to determine the relationship between PLR, NLR, and inflammation in ESRD patients. This was a cross‐sectional study involving 62 ESRD patients (29 females, 33 males; mean age, 49.6 ± 14.6 years) receiving PD or HD for ≥6 months in the Dialysis Unit of Necmettin Erbakan University. PLR, NLR, C‐reactive protein, TNF‐α, IL‐6 levels were measured. PLR, NLR, serum high sensitive C‐reactive protein, IL‐6, and TNF‐α levels were significantly higher in PD patients when compared with HD patients. ESRD patients with PLR ≥ 140 had significantly higher NLR, IL‐6, and TNF‐α levels when compared to patients with PLR < 139. In the bivariate correlation analysis, PLR was positively correlated with NLR, IL‐6, and TNF‐α in this population. When we compared the association of PLR and NLR with IL‐6 (r = 0.371, P = 0.003 vs. r = 0.263, P = 0.04, respectively) and TNF‐α (r = 0.334, P = 0.008 vs. r = 0.273, P = 0.032, respectively), PLR was found to be superior to NLR in terms of inflammation in ESRD patients. Simple calculation of PLR can predict inflammation better than NLR in ESRD patients.     

A taxonomy and evaluation for developing 802.11‐based wireless mesh network testbeds

The definition of wireless mesh networks (WMNs) has been used in the literature to connote and epitomize the ideal, ubiquitous, pervasive, and autonomic networking technology. An increasing interest has been emerging on the development of 802.11‐based WMN testbeds to test the new ideas and approaches more realistically as opposed to relying solely on simulations. Although the developed testbeds have provided several insights to researchers for furthering the technology, there are still several issues that need to be addressed, particularly, with the approval of new standards, such as IEEE 802.11s, IEEE 802.11n, and IEEE 802.16, and upcoming protocols, such as IEEE 802.11ac, 802.11ad, 802.11ah, and 802.11af TV White Space efforts. In this paper, our goal is to provide a taxonomy and insightful guidelines for the creation of 802.11‐based WMN testbeds as well as to identify several features that future WMN testbeds should possess. Utilizing these features, we evaluate the existing WMN testbeds. Finally, in addition to the existing WMN testbed experiments conducted at several layers of the protocol stack, we provide a list of open future research issues that can benefit from experiments on WMN testbeds. Copyright © 2011 John Wiley & Sons, Ltd.     

Biological,Chemical, and Electronic Applications of Nanofibers

With their high‐surface‐to‐volume ratio, nanofibers have been postulated to increase interactions between nanofibrous materials and targeted substrates, which are helpful to overcome many obstacles and enhance the efficiency in a diverse number of applications. Over the past decade, many studies have been published on the fabrication of nanofibers and their applications in various fields. In this review, novel biological, chemical, and electrical characteristics of nanofibers as well as their recent status and achievements in medicine, chemistry, and electronics are analyzed. It is found that nanofibers can induce fast regeneration of many tissues/organs in medical applications and improve the efficiency of many chemical and electronics applications.

     

Impact of Surface Treatment on the Structural and Electronic Properties of Polished CdZnTe Surfaces for Radiation Detectors

We present the effects of surface treatments on the structural and electronic properties of chemomechanically polished Cd_0.9Zn_0.1Te before contact deposition. Specifically, polished CdZnTe (CZT) samples were treated with four distinct chemical etchants: (1) bromine methanol (BM), (2) bromine in lactic acid, (3) bromine in methanol followed by bromine–20% lactic acid in ethylene glycol, and (4) hydrochloric acid (HCl). The surface structure and surface electronic properties were studied with atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). AFM images showed that three of the four etchants significantly altered the surface morphology and structure of CZT. All etchants created smoother surfaces; however, all except HCl also introduced high densities of defects. HCl was found to not affect the surface structure. XPS measurements indicated that a thick, ～3 nm to 4 nm, TeO₂ layer formed about 1 h after etching; hence, it is very important to process devices immediately after etching to prevent oxide formation.     

Damage to Treasury: Abnormally Low Tenders in Public Construction Works

The purpose of this paper is to determine the adverse effect of abnormally low tenders (ALTs) on public construction works in Turkey. A comprehensive literature review was performed to investigate the reasons of ALTs. This paper categorizes the reasons behind ALTs with the help of a questionnaire to which 430 construction companies responded. A detailed analysis of the submitted questionnaires revealed a number of reasons for ALTs and their adverse effect on the construction industry. Staying in the business, miscalculation of bid price, work experience document, and inaccuracy of the conceptual cost were found to be the main reasons behind ALTs. A better database system for contractors on market unit prices, a better quality control assessment in construction and postconstruction phases, full complete design documents in tender packages, and a better evaluation system on the assessment of ALTs are recommended by the study.     

Influence of osmolytes on the stability of thylakoid‐based dye‐sensitized solar cells

In recent years, there has been considerable interest in incorporating naturally occurring components of the photosynthetic apparatus into man‐made solar cells, because of the high quantum efficiency of photosynthetic reaction centers. One hurdle to overcome regarding the use of native membranes in these devices is their limited lifespans. In this study, we used stabilizers to increase the long‐term viability of biomolecules in vitro, thereby alleviating this challenge. In this regard, it is known that osmolytes, such as glycine betaine (GB) and sucrose, preserve photosynthetic activity in isolated photosystems. Upon investigation of the thermal protection properties of GB and sucrose in thylakoid‐based dye‐sensitized solar cells, we report that the addition of GB and sucrose to the thylakoid photosensitizer maintains nonzero photocurrent in the thylakoid‐based solar cell upon heating to 50°C. At 50°C, the GB‐containing cell displayed about a fourfold increase in photocurrent than the control cell, in which the photocurrent was decreased to nearly zero. The addition of 0.5M and 1M sucrose has respectively caused nearly 40% and 70% increases in photoinduced electron transfer activity over the control at 35°С. Similarly, though to a lesser extent, 1M GB caused an approximate 40% increase in electron transfer activity as well. Moving forward, this approach will be extended to alternative membrane protein isolation strategies, allowing for an accurate comparison with traditional detergent‐isolated complexes, with the ultimate goal of developing a cost‐effective and sustainable solar cell.