Graphene-based bipolar plates for polymer electrolyte membrane fuel cells

Bipolar plates (BPs) are a major component of polymer electrolyte membrane fuel cells (PEMFCs). BPs play a multifunctional character within a PEMFC stack. It is one of the most costly and critical part of the fuel cell, and hence the development of efficient and cost-effective BPs is of much interest for the fabrication of next-generation PEMFCs in future. Owing to high electrical conductivity and chemical inertness, graphene is an ideal candidate to be utilized in BPs. This paper reviews recent advances in the area of graphene-based BPs for PEMFC applications. Various aspects including the momentous functions of BPs in the PEMFC, favorable features of graphene-based BPs, performance evaluation of various reported BPs with their advantages and disadvantages, challenges at commercial level products and future prospects of frontier research in this direction are extensively documented.     

Review of materials used in laser-aided additive manufacturing processes to produce metallic products

Rapid prototyping (RP) or layered manufacturing (LM) technologies have been extensively used to manufacture prototypes composed mainly of plastics, polymers, paper, and wax due to the short product development time and low costs of these technologies. However, such technologies, with the exception of selective laser melting and sintering, are not used to fabricate metallic products because of the resulting poor life, short cycle, poor surface finish, and low structural integrity of the fabricated parts. The properties endowed by these parts do not match those of functional parts. Therefore, extensive research has been conducted to develop new additive manufacturing (AM) technologies by extending existing RP technologies. Several AM technologies have been developed for the fabrication of metallic objects. These technologies utilize materials, such as Ni-, Al-, and Ti-based alloys and stainless steel powders, to fabricate high-quality functional components. The present work reviews the type of materials used in laser-based AM processes for the manufacture of metallic products. The advantages and disadvantages of processes and different materials are summarized, and future research directions are discussed in the final section. This review can help experts select the ideal type of process or technology for the manufacturing of elements composed of a given alloy or material (Ni, Ti, Al, Pb, and stainless steel).     

苦丁茶提取物对N80钢的缓蚀作用

采用傅里叶变换红外光谱、气相色谱-质谱、电化学阻抗谱、极化曲线和扫描电子显微镜研究了苦丁茶(KDC)提取物在含3.5%NaCl(质量分数)和饱和CO_2溶液中对N80钢的缓蚀作用。结果表明:苦丁茶提取物属于混合型缓蚀剂;该缓蚀剂对N80钢在含3.5%NaCl和饱和CO_2溶液中具有一定的缓蚀作用,能够有效抑制N80钢的腐蚀;缓蚀率随着缓蚀剂含量的增大而提高,当加入4%(体积分数)苦丁茶缓蚀剂时,根据极化曲线和电化学阻抗谱计算得到的缓蚀率分别达到了92.47%和96.90%。     

Optimization of ingredient levels for manufacturing malted milk beverage using response surface methodology

The malted milk beverage was prepared with varying levels of milk fat, wort and stabilizer–emulsifier mix using response surface methodology. Milk fat had a significant effect on all sensory attributes at the linear, quadratic or interactive levels. Wort level affected the flavour of the beverage at the linear ( P <  0.01) term. The addition of stabilizer–emulsifier mix enhanced the overall acceptability of the product by significantly affecting the flavour ( P <  0.01) and mouthfeel ( P <  0.01). The optimum levels of ingredients to manufacture acceptable quality malted milk beverages were 1.93 g/100 g milk fat, 62.96 g/100 g wort and 0.09 g/100 g stabilizer–emulsifier mix.     

EFFICIENCY OF ANACARDIC ACID AS PRESERVATIVE IN TOMATO PRODUCTS

Anacardic acid, 6[8'(Z), 11'(Z),14'-pentadecatrienyl] salicylic acid is the main active principle of Anacardium occidentale ( Anacardiceae ), the cashew. Cashew nut shell liquid (CNSL) contains approximately 70% anacardic acids, 18% cardol, 5% cardanol, and some other phenols and less polar substances. Because of the presence of anacardic acids, the CNSL exhibits potent antimicrobial activity. In view of this and the potent antimicrobial activity of anacardic acid observed in our previous study, the present study was planned to evaluate the anacardic acid isolated by us in our previous study as a food preservative. The effect of anacardic acid at 0.014% (w/w) was studied in tomato paste and tomato ketchup inoculated with 2  ×  10⁴ cfu/g of Staphylococcus aureus, Bacillus subtilis and Escherichia coli and stored at room temperature. Good activity was observed, as no viable growth after 28 days in both the products. Results showed that anacardic acid was active against both gram-positive and gram-negative bacteria. Results of the study indicated that anacardic acid can act as a potential preservative in tomato products and can be considered as an alternative natural preservative over the synthetic preservatives.

PRACTICAL APPLICATIONS

When safeties of synthetic preservatives are questioned, natural substances of plant origin may appeal to the public. The anacardic acid isolated form cashew nut shell is present in cashew nut, which is being consumed by a number of people as a food material. So it is relatively safe to use as an alternate to the existing synthetic preservatives.     

人的世界观与其在公共健康领域内科学知识间的文化差距

本文尝试对健康与卫生领域内的公众理解科学加以测度,并针对“文化差距模型”的有效性进行测试。测试前的自由回答式问卷调查是在印度一个宗教文化节日中进行的跨区域调查。调查对象有3484人,他们的回答被编码并输入电脑,建立了数据库。这些数据被用来测度目标人群对来自日常生活的5个科学概念形成的文化差距。在发展中国家,现代教育的正式体系成为了人们普遍的思想文化结构形成的决定性因素。在自然事物形成的科学结构与人们思想复杂性之间存在着文化差距。文中被调查的概念所体现出来的文化差距有着很大不同,这种差距是科学信息本质的一种功能。     

Dust acoustic shock waves in magnetized dusty plasma

We have presented a theoretical study of the dust acoustic(DA) shock structures in a magnetized,electron depleted dusty plasma in the presence of two temperature superthermal ions. By deriving a Korteweg–de Vries–Burgers equation and studying its shock solution, we aim to highlight the effects of magnetic field and obliqueness on various properties of the DA shock structures in the presence of kappa-distributed two temperature ion population. The present model is motivated by the observations of Geotail spacecraft in the Earth?s magnetotail and it is seen that the different physical parameters such as superthermality of the cold and hot ions, the cold to hot ion temperature ratio, the magnetic field strength, obliqueness and the dust kinematic viscosity greatly influence the dynamics of the shock structures so formed. The results suggest that the variation of superthermalities of the cold and hot ions have contrasting effects on both positive and negative polarity shock structures.Moreover, it is noted that the presence of the ambient magnetic field affects the dispersive properties of the medium and tends to make the shock structures less wide and more abrupt. The findings of present investigation may be useful in understanding the dynamics of shock waves in dusty plasma environments containing two temperature ions where the electrons are significantly depleted.     

Pipeline for illumination correction of images for high‐throughput microscopy

The presence of systematic noise in images in high‐throughput microscopy experiments can significantly impact the accuracy of downstream results. Among the most common sources of systematic noise is non‐homogeneous illumination across the image field. This often adds an unacceptable level of noise, obscures true quantitative differences and precludes biological experiments that rely on accurate fluorescence intensity measurements. In this paper, we seek to quantify the improvement in the quality of high‐content screen readouts due to software‐based illumination correction. We present a straightforward illumination correction pipeline that has been used by our group across many experiments. We test the pipeline on real‐world high‐throughput image sets and evaluate the performance of the pipeline at two levels: (a) Z′‐factor to evaluate the effect of the image correction on a univariate readout, representative of a typical high‐content screen, and (b) classification accuracy on phenotypic signatures derived from the images, representative of an experiment involving more complex data mining. We find that applying the proposed post‐hoc correction method improves performance in both experiments, even when illumination correction has already been applied using software associated with the instrument. To facilitate the ready application and future development of illumination correction methods, we have made our complete test data sets as well as open‐source image analysis pipelines publicly available. This software‐based solution has the potential to improve outcomes for a wide‐variety of image‐based HTS experiments.     

Tomato Product Quality from Transgenic Fruits with Reduced Pectin Methylesterase

Juice from transgenic tomato (Lycopersicon esculentum cv Rutgers) fruits with reduced levels of pectin methylesterase (PME) activity due to the expression of a PME antisense gene exhibited improvement in quality. The percentage increase in juice from transgenic fruits over that of juice from wild type Rutgers ranged between 5.1–5.3 for total solids, 3.8–6.1 for soluble solids, 70–80 for efflux viscosity, 180–220 for serum viscosity and about 50 for precipitate weight ratio. Time of harvest had no effect on quality of juice. Ketchup prepared from transgenic fruit juice had a lower Bostwick value, reduced serum separation and high serum viscosity compared to ketchup from parental Rutgers.