Tool Wear and its Effect on Residual Tensile Strength in Drilling of Quartz Cyanate Ester Polymeric Composite

Quartz-Fibre-Reinforced cyanate ester Plastics (QFRP) has superior performance in terms of mechanical, electromagnetic properties and are being widely used in military applications. Drilling is the general machining process for making hole to join the composite part to another sub-assembly. This study presents an influence of optimized drilling parameters on carbide tool wear and its impact on hole characteristics in QFRP composite. The aim is to achieve the optimum use of drill during the drilling process from application perspective without compromising the quality. In addition, the effect of tool wear and its impact on residual tensile strength of quartz composite are studied. The dominant wear mechanism observed is flank wear caused by the abrasive nature of the quartz fibre. The tool wear and delamination factor after drilling 200 holes are 186 µm and 1.40 respectively. The residual strength is affected by the tool wear due to relatively poor interlaminar property between fiber and resin in this quartz composite. The residual strength of quartz specimen drilled with the tool after drilling 200 holes is 14 % lower than the property of specimen drilled with fresh drill. The highlight of the present work is a combined analysis of wear in the tool, delamination induced and residual strength of quartz specimen. The results of this study strengthen the understanding of the drilling process of quartz polymeric composite material in aerospace applications

Impact of non-idealities on the Performance of an Ultracapacitor based Bidirectional DC/DC Converter

This paper analyses the impact of non-idealities on the performance of an ultracapacitor based bidirectional DC/DC converter. In particular, this work analyses the impact of ON state resistance of the MOSFET switches on the performance of bidirectional DC/DC converter. It is shown that, under particular operating conditions, the ON state resistance of the MOSFET can have a significant impact on the performance of th DC/DC converter and can cause an unstable response. An analytical expression is derived to identify the operating conditions under which the non-idealities can have a significant impact on the performance of the DC/DC converter. Simulation results are presented to aid the analysis reported in this paper. © 2020 IEEE

Multimode Operation of a PV-Battery System fed Brushless DC Motor Drive

Utilization of energy storage systems along with Photovoltaic systems, can provide an efficient solution to overcome the challenges associated with renewable energy sources. This paper proposes an algorithm for the multimode operation of a Brushless DC motor drive fed using a combination of Photovoltaic System and battery-based energy storage. Based on the solar irradiation and the state of charge of the battery, the proposed algorithm identifies a control scheme wherein the entire system operates in Four different modes. The working of the PV-Battery System fed Brushless DC Motor Drive under various operating modes is presented and is verified using simulation analysis performed in MATLAB/Simulink. © 2020 IEEE

Curcumin-Loaded Apotransferrin Nanoparticles Provide Efficient Cellular Uptake and Effectively Inhibit HIV-1 Replication In Vitro

Curcumin (diferuloylmethane) shows significant activity across a wide spectrum of conditions, but its usefulness is rather limited because of its low bioavailability. Use of nanoparticle formulations to enhance curcumin bioavailability is an emerging area of research.In the present study, curcumin-loaded apotransferrin nanoparticles (nano-curcumin) prepared by sol-oil chemistry and were characterized by electron and atomic force microscopy. Confocal studies and fluorimetric analysis revealed that these particles enter T cells through transferrin-mediated endocytosis. Nano-curcumin releases significant quantities of drug gradually over a fairly long period, ∼50% of curcumin still remaining at 6 h of time. In contrast, intracellular soluble curcumin (sol-curcumin) reaches a maximum at 2 h followed by its complete elimination by 4 h. While sol-curcumin (GI(50) = 15.6 µM) is twice more toxic than nano-curcumin (GI(50) = 32.5 µM), nano-curcumin (IC(50)<1.75 µM) shows a higher anti-HIV activity compared to sol-curcumin (IC(50) = 5.1 µM). Studies in vitro showed that nano-curcumin prominently inhibited the HIV-1 induced expression of Topo II α, IL-1β and COX-2, an effect not seen with sol-curcumin. Nano-curcumin did not affect the expression of Topoisomerase II β and TNF α. This point out that nano-curcumin affects the HIV-1 induced inflammatory responses through pathways downstream or independent of TNF α. Furthermore, nano-curcumin completely blocks the synthesis of viral cDNA in the gag region suggesting that the nano-curcumin mediated inhibition of HIV-1 replication is targeted to viral cDNA synthesis.Curcumin-loaded apotransferrin nanoparticles are highly efficacious inhibitors of HIV-1 replication in vitro and promise a high potential for clinical usefulness

A Review on Hydrothermal Liquefaction of Biomass

The rapid depletion of conventional fossil fuels and day-by-day growth of environmental pollution due to use of extensive use of fossil fuels have raised concerns over the use of the fossil fuels; and thus search for alternate renewable and sustainable sources for fuels has started in the last few decades. In this context biomass derived fuels seems to be the promising path; and various routes are available for the biomass processing such as pyrolysis, transesterification, hydrothermal liquefaction, steam reforming, etc.; and the hydrothermal liquefaction (HTL) of wet biomass seems to be the promising route. Therefore, this article briefly enlightened a few concepts of HTL such as the elemental composition of bio-crude obtained by HTL, different types of feedstock adopted for HTL, mechanism of HTL processes, possible process flow diagrams for HTL of both wet and dry biomass and energy efficiency of the process. In addition, this article also enlisted possible future research scope for concerned researchers and a few of them are setting up HTL plant suitable for both wet and dry biomass feedstock; analysing influence of parameters such as temperature, pressure, residence time, catalytic effects, etc.; deriving optimized pathways for better conversion; and development of theoretical models representing the process to the best possible accuracy depending on nature of feedstock

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Not AvailableAgrobacterium mediated transformation was studied in different explants of sorghum through transient gus expression. Our studies showed that immature embryos and calli derived from immature inflorescences were ideal target tissues for obtaining high gus expression with the construct pDM80S. Since the availability of immature embryos and immature inflorescences is limited to the crop season, in vitro protocols based on mature seed as explant source were tested. A simple, economic and time-saving procedure has been developed using shoot apices from three-day old germinated seedlings as target for Agrobacterium infection. Studies on callus induction and regeneration using different explants of sorghum showed that calli derived from immature inflorescences have high regeneration capacity. Callus induction from mature seeds was poor, while in shoot apex explants callus induction was high, but regeneration was low. Therefore, two alternative methods were developed: (i) recovery of plants through direct root induction from shoot apices and (ii) induction of multiple shoots using 6-benzylaminopurine. Genotype specific response to BAP was observed. In addition, infection of 3 day old shoot apices showed high gus expression in all the three elite lines of sorghum tested. These explants can be infected with Agrobacterium and then used either for multiple shoot induction or for obtaining transformed plants directly after root inductionNot Availabl

Mathematical modeling and stability analysis of an ultracapacitor based energy storage system considering non-idealities

The typical configuration of an ultracapacitor-based energy storage system comprises of an ultracapacitor stack along with a bidirectional DC/DC converter. Accordingly, this paper focuses on developing mathematical models for an ultracapacitor-based energy storage system considering non-idealities. Subsequently, small signal stability analysis is carried out based on the developed mathematical models. In particular, the impact of non-idealities such as ON-state resistance of the switches on the small signal model of the system is highlighted. It is shown that the transfer function of the system derived by considering the non-idealities has a zero on the right-hand side of the s−plane during the discharging mode. The operating conditions under which a right hand zero can occur are derived, and the behavior of the converter under these operating points is analyzed with the help of simulation results. © 2020 Elsevier Lt

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Not AvailableTransgenic technology serves to introduce gene sequences for expression of a desired trait. Production of transgenic plants is reported in many crops, but commercialization is limited to a few selected crops, such as cotton (Gossypium hirsutum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and canola (Brassica napus L. and B. rapa L.). This paper presents the sequential processes of transgenic event design, event selection, and “cleaning up” genetic background for forward breeding programs. Expression of the foreign gene cannot be viewed in isolation and is more complex than has been assumed because of the interaction of transgene with native genes. Variations among clones and within the progeny are observed, and hence all the clones are taken into account for evaluation. Plant breeding must be involved to move transgenes from transformable but agronomically unacceptable genotypes into elite breeding lines with two backcrosses. Production of transgenic plants in large numbers is diffi cult and laborious and requires large investments. It is worthwhile investing in parallel efforts to incorporate the transgene into improved plant material to satisfy commercial interests.Not Availabl

culture of shoot apical meristems

Not AvailableTwenty-four diverse genotypes of sorghum were evaluated for response to callus induction and plant regeneration with two media viz., MS and NBKNB using shoot tips as the start-material to identify a model genotype. None of the genotypes tested showed promising results. Therefore, alternative methods of in vitro pathways using shoot meristem isolated from shoot tips were explored. Shoot apical meristems were isolated and were induced to multiple shoots or multiple shoot buds pathway by manipulation of thidiazuron (TDZ), 6-benzyl adenine (BAP) and 2, 4- dichlorophenoxy acetic acid (2, 4-D). Choice of the pathway whether large-scale multiplication of shoots or production of target tissues for transformation can be exercised based on the needs and applications. A simple procedure, for large scale handling of shoot tips is described in detail. Electron microscopic studies revealed that meristems isolated from 7-day-old seedlings are superior because of possessing greater number of transformation competent cells.Not Availabl