823 research outputs found

    Detonation driven shock wave interactions with perforated plates

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    The study of detonations and their interactions is vital for the understanding of the high-speed flow physics involved and the ultimate goal of controlling their detrimental effects. However, producing safe and repeatable detonations within the laboratory can be quite challenging, leading to the use of computational studies which ultimately require experimental data for their validation. The objective of this study is to examine the induced flow field from the interaction of a shock front and accompanying products of combustion, produced from the detonation taking place within a non-electrical tube lined with explosive material, with porous plates with varying porosities, 0.7–9.7%. State of the art high-speed schlieren photography alongside high-resolution pressure measurements is used to visualise the induced flow field and examine the attenuation effects which occur at different porosities. The detonation tube is placed at different distances from the plates' surface, 0–30 mm, and the pressure at the rear of the plate is recorded and compared. The results indicate that depending on the level of porosity and the Mach number of the precursor shock front secondary reflected and transmitted shock waves are formed through the coalescence of compression waves. With reduced porosity, the plates act almost as a solid surface, therefore the shock propagates faster along its surface

    Juxtaposing Farmers’ Suicides and Climate Change Vulnerability: An Empirical Analysis of Indian States

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    India’s overall ranking on the Global Climate Risk Index has been deteriorating in recent years, making it more vulnerable to climate risks. It has been indicated in the literature that climate change is also associated with agrarian distress. However, empirical analyses are scanty on this, especially in the Indian context. In this analytical exercise, we tried to explore the association between farmers’ suicides and climate change vulnerability across Indian states. Using data from various sources, we arrive at an Agrarian Vulnerability Index and juxtaposed that with farmers’ suicide data between 1996 to 2015 collected from the National Crime Records Bureau (NCRB). We noted a strong association between climate change vulnerability and farmers’ suicides. The essence of this analysis is to indicate and understand the broad trends and associations. This research, in the process, informs and presses for a systematic, more comprehensive study with an agenda at micro and meso levels to understand the nuances of this association. &nbsp

    Study of detonation interactions inside a 2-D ejector using detonation transmission tubing

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    Biochemical studies on the effect of curcumin and embelin during N-nitrosodiethylamine/phenobarbital induced-hepatocarcinogenesis in wistar rats

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    The biochemical effects of administration of embelin a benzoquinone derivative from Embelia ribes and curcumin (diferuloyl methane) isolated from Curcuma longa against a 2 step hepatocarcinogenic regimen comprising of N-nitrosodiethylamine (DENA)/phenobarbital (PB) was studied in wistar strain male albino rats with respect to lipid profile, renal function tests and levels of blood glucose. Rats administered DENA/PB showed hyper cholesterolaemia, hyper triglyceridaemia, elevated low-density lipoproteins (LDL), free fatty acids (FFA), very-low-density lipoproteins (VLDL) levels and decreased urea levels. Pre- and co-treatment with embelin and curcumin for 14 weeks significantly prevented the biochemical alterations induced by DENA/PB. Results of our study suggest the protective and hypolipidemic effects of embelin and curcumin during chemically- induced hepatocarcinogenesis in wistar rats. © 2009 Academic Journals

    Climate Change Vulnerability in Agriculture Sector: Indexing and Mapping of Four Southern Indian States

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    Agriculture is the sector most vulnerable to climate change due to its high dependence on climate and weather conditions. Climate change is a main challenge for agriculture, food security and rural livelihoods for millions of people in India. Among India’s population of more than one billion people, about 68% are directly or indirectly involved in the agricultural sector. This sector is particularly vulnerable to present-day climate variability. In this paper an attempt is made to map and analyze the vulnerability to climate change in different districts of four south Indian states: Andhra Pradesh, Karnataka, Tamil Nadu and Kerala. We have taken five sources of vulnerability indicators: socio-demographic, climatic, agricultural, occupational and common property resources vulnerabilities to compute the composite vulnerability index. The composite vulnerability index suggests that, Adilabad, Chamarajanagar, Thiruvarur and Kasaragod are the most vulnerable districts of Andhra Pradesh, Karnataka, Tamil Nadu and Kerala respectively, whereas Hyderabad, Belgaum, Thoothukkudi, Kottayam are the least vulnerable districts

    Band structure of topological insulators from noise measurements in tunnel junctions

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    The unique properties of spin-polarized surface or edge states in topological insulators (TIs) make these quantum coherent systems interesting from the point of view of both fundamental physics and their implementation in low power spintronic devices. Here we present such a study in TIs, through tunneling and noise spectroscopy utilizing TI/Al2_2O3_3/Co tunnel junctions with bottom TI electrodes of either Bi2_2Te3_3 or Bi2_2Se3_3. We demonstrate that features related to the band structure of the TI materials show up in the tunneling conductance and even more clearly through low frequency noise measurements. The bias dependence of 1/f noise reveals peaks at specific energies corresponding to band structure features of the TI. TI tunnel junctions could thus simplify the study of the properties of such quantum coherent systems, that can further lead to the manipulation of their spin-polarized properties for technological purposes

    Citrullinemia type 1: genetic diagnosis and prenatal diagnosis in subsequent pregnancy

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    Citrullinemia type 1 was diagnosed by tandem mass spectrometry in a full term male neonate who presented with an acute catastrophic collapse on the 3rd day of life. Both parents were identified to be carriers for the exon 15 p Gly390Arg mutation in the argininosuccinate synthetase gene located at chromosome 9q34.1. Chorionic villus sampling and prenatal genetic testing in the subsequent pregnancy revealed an affected fetus resulting in termination of pregnancy

    Gaint cell tumour of phalynx: have you seen it?

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    Giant cell tumors are rarely seen in the foot. Only 1-2% cases of GCT occur in the foot. They can cause a significant amount of pain and deformity due to their aggressive and recurrent nature whenever it occurs in foot. We present an unusual case of a giant cell tumor of proximal phalynx of middle toe of left foot. 26 year old male came with complaints of pain and swelling over the middle toe of left foot since 6 months. Clinical and radiological features showed features consistent with GCT. Foot Function Index revealed a) Pain scale: 29 / 50 = 58%, b) Disability scale: 56 / 90 = 62%, c) Activity limitation scale: 8 / 30 = 27%. Authors performed enbloc resection with ray amputation of 3rd toe. Histopathological examination of excised specimen revealed classic findings of mononuclear cells with interspersed fibro-collagenous strands and numerous multinucleated osteoclast-like giant cells which confirmed our diagnosis. Patient was serially followed up and at 6 months followup, there were no signs of recurrence with markedly improved foot function index
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