341 research outputs found

    Research and development of HgZnTe as an infrared material

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    Interfacial morphology and Fermi level pinning behavior at the interfaces of Al, Ag, and Pt with UHV-cleaved CdTe and ZnTe have been studied using X-ray and ultraviolet photoemission spectroscopies. Results are compared to metal/HgCdTe interface formation, where the weak HgTe bond and consequent ease of Hg loss strongly influence semiconductor disruption and metal-semiconductor intermising. For Al/CdTe, the strong Al-Te reaction yields a significantly more extensive Al-Te reacted region than has been observed for HgCdTe. The Al/ZnTe interface is observed to be more abrupt than Al/CdTe. The final Fermi level pinning positions, Ef-Evbm for Al, Ag, and Pt on p-type CdTe and p-ZnTe have been determined. Efi is found to be roughly the same for both CdTe and ZnTe, with the value for ZnTe lying approximately 0.2 eV closer to the VBM for all three metals. From these results, one would expect Schottky barriers of about the same height for these metals on p-CdTe and p-ZnTe; and also that, in principle, metal interfaces with the two alloys HgCdTe and HgZnTe would have the same properties. Comparisons and implications for electrical behavior of metal contacts to the alloys are discussed

    Biosynthesis of silver nanoparticles by plants crude extracts and their characterization using UV, XRD, TEM and EDX

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    Plant extracts are very cost effective and eco-friendly, thus, can be an economic and efficient alternative for the large-scale synthesis of nanoparticles. The preparation of stable, uniform silver nanoparticles by reduction of silver ions with Emblica officinalis, Terminalia catappa and Eucalyptus hybrida extract is reported in the present paper. It is a simple process of global research interest for obtaining silver nanoparticles in least amount of time. These nanoparticles were  characterized with UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy diffraction X- ray (EDX analysis which revealed that the silver nanoparticles are polydisperse and of different morphologies ranging from 20 to 80 nm in size. XRD results reveal that these nanostructures exhibit a face-centered cubic crystal structure. The UV/Vis spectra absorption peak confirms their production. Pioneering of reliable and eco-friendly process for synthesis of metallic nanoparticles biologically is an important step in the field of application of nanobiotechnology. Thus, these silver nanoparticles (Ag- NPs) may prove as a better candidate for drugs and can potentially eliminate the problem of chemical agents because of their biogenic nature. The indiscriminate use of antibiotics has fuelled the development of drug resistance at an alarming rate. To overpower this burning problem, the Ag-NPs may prove to be a universal solution.Key words: Nanobiotechnology, silver nanoparticles (Ag-NPs), Emblica officinalis, Terminalia catappa and Eucalyptus hybrida

    Finite element analysis of protective bicycle helmet & dummy head under dynamic loading

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    Cycling is a good activities particularly for recreation, exercise, and transportation. However, cycling related to the head injury is a significant contributor to hospitalization and death. Previous literatures indicates that the available helmets have less effective in preventing head injuries among cyclists. Moreover, most of the available helmets have been tested for only a few loading conditions. Therefore, the purpose of this study is to use finite element models to evaluate the protective effect of a helmet against various impact velocities. The head and helmet model has been developed using computational software. This study focus on the explicit dynamic analysis which performed in ANSY-WORKBENCH with loading condition in term of various impact velocity impacted on front and side of the head model. The results indicates the differences between the frontal and side simulations. They have been compared to identify the protective effect of the helmet and head

    Development of Artificial Hand Gripper by using Microcontroller

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    This paper focuses on the development of a measurement hand gripper to help handicap patient due to accident and diseases. Basically, when the patient needed to perform exercises they must get an appointment with a doctor. Normally this will take few weeks or months. This is because the rehabilitation devices at Physiotherapy Department in hospital are very limited. From this problem, we suggest to develop a reasonably cheap home-based rehabilitation measurement devices which can perform the task of assisting paralyze patient at home. The basic movement of the patient was limited from a wrist, elbow and shoulder. The development of this project involves the designing of a sensors equipped Smart Glove and a measurement hand gripper device. The hand gripper device will move based on a human operator’s finger movement using the Smart Glove. The purpose of our project is to design and develop a master-slave system robotic hand which can be a substitution for the paralyzed hand in therapy to aid in recovery process of patients upper limb function. The project involves an Arduino microcontroller for the instrumentation, communication and controlling applications. A series of flex sensors are fitted in a master glove to get readings from the movement of human fingers. Microcontroller will further use this information to control multiple servos that controls the movement of slave robotic hand

    Cytomorphological Studies on Stem of Luffa echinata Roxb

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    Luffa echinata Roxb., commonly known as Bindal in Hindi is used for its hypoglycemic activity in the indigenous system of medicine. No pharmacognostical study on stem is reported in the literature till date; therefore, it was decided to study macroscopical and cytomorphological characters in detail to bring out salient diagnostic features. The stem pieces available in the market are 1.5–17 cm long and 5–8 mm in diameter, showing yellowish-brown to brownish-black surface with longitudinal furrows, fracture is fibrous, and taste is bitter. Mature stem shows single-layered epidermis, seven layers of collenchyma below five ridges but one to two layers of parenchyma in rest of the region beneath the epidermis, continuous wide wavy layer of pericycle composed of three to eight layers of fiber. There are five conjoint bi-collateral open vascular bundles one below each ridge and additional four medullary vascular bundles in the pith each facing furrows

    Day-To-Day Variability of IEC at Mid Latitude During Sunspot Minimum

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    Identification of a suitable clustering method and allocation strategy for core set development in salt stress tolerant rice (Oryza sativa) germplasm

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    Preserving genetic diversity in repository of germplasm is essential for crop breeding programs. However, maintenance and protection of all the germplasms in gene bank is difficult due to its voluminous size. Hence the development of core set with minimum number of germplasm representing maximum genetic diversity of the population has become an alternative. From the available clustering methods and allocation strategies, identifying a suitable combination is essential for the development of species-specific core set. In the present study, data on 219 salt stress tolerant rice (Oryza sativa L.) germplasm accessions with 14 phenotypic traits and 2915 genome wide Single Nucleotide Polymorphisms (SNPs) is considered to identify a suitable combination of clustering method and allocation strategy for core set development. Eight different combinations consisting of two clustering methods, viz. Ward’s and UPGMA along with four different allocation strategies, viz. L, D, LD and NY allocation with three level of sampling intensities (20%, 25% and 30%) have been tried. Based on the study carried out during 2013-14 at Indian Agricultural Statistics Research Institute, New Delhi, it is concluded that the Ward’s clustering method with NY allocation, irrespective of sampling intensity, is suitable for developing core set with maximum diversity

    Glutamine addiction promotes glucose oxidation in triple-negative breast cancer

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    Glutamine is a conditionally essential nutrient for many cancer cells, but it remains unclear how consuming glutamine in excess of growth requirements confers greater fitness to glutamine-addicted cancers. By contrasting two breast cancer subtypes with distinct glutamine dependencies, we show that glutamine-indispensable triple-negative breast cancer (TNBC) cells rely on a non-canonical glutamine-to-glutamate overflow, with glutamine carbon routed once through the TCA cycle. Importantly, this single-pass glutaminolysis increases TCA cycle fluxes and replenishes TCA cycle intermediates in TNBC cells, a process that achieves net oxidation of glucose but not glutamine. The coupling of glucose and glutamine catabolism appears hard-wired via a distinct TNBC gene expression profile biased to strip and then sequester glutamine nitrogen, but hampers the ability of TNBC cells to oxidise glucose when glutamine is limiting. Our results provide a new understanding of how metabolically rigid TNBC cells are sensitive to glutamine deprivation and a way to select vulnerable TNBC subtypes that may be responsive to metabolic-targeted therapies
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