226 research outputs found

    EPFM Analysis of Subsurface Crack Beneath a Wheel Flat Using Dynamic Condition

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    AbstractDuring running due to frequent braking and suddenly jamming of brakes the Railway wheel skids over rails. This frequent skidding removes large amount of metal from the surface known as Wheel-flat defect. In this paper the wheel-flat and a subsurface crack in the beneath is studied using FEA. If the wheel-flat is not detected early the subsurface crack can originate in the beneath due to inclusion, may leads to fatal accidents. In this study wheel material is taken Elastic-plastic and J-Integral factor has been obtained. The wheel–rail vehicle is modelled as a mass–spring–damper syste

    Utilization of chlorophyll content index (CCI) to infer yellow rust severity in wheat (Triticum aestivum L.)

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    Stripe rust caused by Puccinia striformis Westend. f. sp. tritici Eriks. (Pst) is a major constraint to wheat production in Northern India. In this study, 616 indigenous germplasm (IC) accessions of wheat were screened under field conditions against mixture of Pst isolates at DWR Karnal during 2012-13 crop season. Out of 616 accessions, 197 accessions were observed to be resistant (R), 115 moderately resistant (MR) to moderately susceptible (MS) and 304 as susceptible (S) against yellow rust. On the basis of days to heading, the accessions were grouped into four classes (early, medium early, medium late and late). Chlorophyll content index (CCI) recorded in flag leaf showed significant differences between resistant and susceptible lines in each classified group at 5% level of significance. The difference for CCI between resistant and moderately resistant plants was negligible, however in comparison with resistant plants, susceptible plants showed loss of 35-39% of chlorophyll. There was negative correlation (a correlation coefficient of – 0.60) between chlorophyll content and disease severity due to stripe rust in susceptible accessions

    An Evaluation of the sliding Wear Behaviour of SiC Particles Reinforced Copper Alloy Composite Materials

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    The present paper aims at evaluation of the sliding wear behaviour of SiC particles reinforced copper (phosphor-bronze) alloy composite materials studied as a function of sliding speed and applied loads under unlubricated conditions. The content of SiC particles in the composites was varied from 1-5% in steps of 2% by weight. A pin-on-disc wear testing machine was used to evaluate the wear rate, in which EN24 steel disc was used as the counterface. Loads of 20-160 N in steps of 20 N and speeds of 1.25, 1.56, 1.87 m/s were employed. The results indicated that the wear rate of both the composites and the matrix alloy increased with increase in load and sliding speed. However, the composites exhibited lower wear rate than the alloys.It was found that above a critical applied load, there exists a transition from mild to severe wear both in the unreinforced alloy and in the composites. But the transition loads for the composites were much higher than that of the unreinforced alloy. The transition loads increase with the increase in weight % of SiC particles, but decrease with the increase in sliding speeds. SEM analysis of the wear surfaces as well as the sub-surfaces are used to explain the observations made

    Evaluation and identification of resistance to powdery mildew in Indian wheat varieties under artificially created epiphytotic

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    Wheat production is globally weighed down by several biotic factors of which rusts and powdery mildew are the most important. Powdery mildew, caused by Blumeria graminis f. sp. tritici, is becoming a disease of major importance in the North Western Plains Zone and Northern Hills Zone of the country. In the present context ofclimate variability, diseases like powdery mildew can assume greater importance in wheat breeding programs. Importance of basic studies on powdery mildew is the need of hour. A set of 370 Indian bread wheat, durum, dicoccum and triticale varieties were screened using mixture of natural occurring pathotypes from four locations(viz., Karnal, Ludhiana, Dhaulakuan and Yamunanagar) under polyhouse conditions. Data were recorded on the severity of infection based on 0-9 scale. Out of 370, only 23 varieties (Amrut, DDK 1025, DWR 1006, DWR 195, GW 1139, HD 4672, HD 4530, HD 2278, HD 1981, DDK 1001, HI 8627, Jay, TL 2942, DT 46, K 8020, DDK 1029, K 9107, K 816, Lok 1, MACS 6145, DDK 1009, NP 111 and NP 200) had shown immune reaction (0) whereas 150, 83 and 114 varieties have shown resistance (1-3), moderately susceptible (4-6) and highly susceptible (>6) response respectively against powdery mildew. Data indicated that there is an urgent need to broaden the genetic base of wheat by identifying and introgressing new sources of powdery mildew resistance. With limited sources of PM resistance available, above identified genotypes can be further used and characterized for resistance breeding programs in India

    Performance of an Orifice Compensated Two-Lobe Hole-Entry Hybrid Journal Bearing

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    The work presented in this paper aims to study the performance of a two-lobe hole-entry hybrid journal bearing system compensated by orifice restrictors. The Reynolds equation governing the flow of lubricant in the clearance space between the journal and bearing together with the equation of flow through an orifice restrictor has been solved using FEM and Galerkin's method. The bearing performance characteristics results have been simulated for an orifice compensated nonrecessed two-lobe hole-entry hybrid journal bearing symmetric configuration for the various values of offset factor (), restrictor design parameter (2), and the value of external load (0). Further, a comparative study of the performance of a two-lobe hole-entry hybrid journal bearing system with a circular hole-entry symmetric hybrid journal bearing system has also been carried out so that a designer has a better flexibility in choosing a suitable bearing configuration. The simulated numerical results indicate that for the two-lobe symmetric hole-entry hybrid journal bearing system with an offset factor () greater than one provides 30 to 50 percent larger values of direct stiffness and direct damping coefficients as compared to a circular symmetric hole-entry hybrid journal bearing system

    Compensated hole-entry Hybrid Journal Bearing by CFV Restrictor under Micropolar Lubricants / Nathi Ram...[et al.]

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    In this work, the performance of hole-entry hybrid journal bearing compensated by constant flow valve (CFV) restrictor under micropolar lubricants has been numerically simulated. Reynolds equation for micropolar fluid lubricated bearing has been solved with finite element technique. Performance of bearing has been evaluated as a function of coupling number N² . The simulated characteristics of bearing under micropolar lubricants have been compared with similar bearing under Newtonian lubricant. The results are presented for the selected micropolar parameters N² and lm. Simulated results indicate that the bearing under micropolar lubricants exhibits the increased values of minimum fluid film thickness, stiffness and damping coefficients than similar bearing under Newtonian lubricant. Further, the coefficient of friction decreases for a bearing when it is operating under micropolar lubricant than Newtonian lubricant

    Review article: diagnosis, management and patient perspectives of the spectrum of constipation disorders.

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    BACKGROUND: Chronic constipation is a common, heterogeneous disorder with multiple symptoms and pathophysiological mechanisms. Patients are often referred to a gastroenterology provider after laxatives fail. However, there is limited knowledge of the spectrum and management of constipation disorders. AIM: To discuss the latest understanding of the spectrum of constipation disorders, tools for identifying a pathophysiologic-based diagnosis in the specialist setting, treatment options and the patient\u27s perspective of constipation. METHODS: Literature searches were conducted using PubMed for constipation diagnostic criteria, diagnostic tools and approved treatments. The authors provided insight from their own practices. RESULTS: Clinical assessment, stool diaries and Rome IV diagnostic criteria can facilitate diagnosis, evaluate severity and distinguish between IBS with constipation, chronic idiopathic constipation and dyssynergic defecation. Novel smartphone applications can help track constipation symptoms. Rectal examinations, anorectal manometry and balloon expulsion, assessments of neuromuscular function with colonic transit time and colonic manometry can provide mechanistic understanding of underlying pathophysiology. Treatments include lifestyle and diet changes, biofeedback therapy and pharmacological agents. Several classes of laxatives, as well as prokinetic and prosecretory agents, are available; here we describe their mechanisms of action, efficacy and side effects. CONCLUSIONS: Constipation includes multiple overlapping subtypes identifiable using detailed history, current diagnostic tools and smartphone applications. Recognition of individual subtype(s) could pave the way for optimal, evidence-based treatments by a gastroenterology provider

    Karakter Pertumbuhan Bawang Merah (Allium Ascalonicum L.) Varietas Lokal Samosir Pada Beberapa Dosis Iradiasi Sinar Gamma

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    The aim of the research was to identify growth characters of shallot var. local samosir with gammarays irradiation. Research was conducted at the Jl. Selamet Ketaren, Medan with a height of 25meter above sea level began from April until July 2014. Bulbs of shallot were exposed to severaldoses (0, 1, 2, 3, 4, 5, and 6 Gy) using Co60 source. Differencies of growth characters (shoot length,leaf number and tiller number per clump, harvest time, fresh and dry weight of bulb per plant, bulbdiameter and average weight per bulb) was analyze by t test using minitab v.16. The results showedshoot length 6 weeks after planting (WAP) were shorter 1.97cm, 2.38cm, 3.1cm, 4.73cm and4.49cm at doses 2,3,4,5,6 Gy; leaf number 2 WAP were reduced 35.16% and 39.24% at dose 5 and6 Gy, meanwhile tiller number 6 WAP was increased 13.88% at dose 6 Gy respectively comparedto control. Fresh weight and dry weight of bulb were lighter 30,39% and 37,04% at doses 5 Gy and38,52% and 47,44% at doses 6 Gy; average weight per bulb were lighter 23,2%, 47,64% and47,98% and bulb diameter were smaller 11,48%, 25,48% and 30,41% at doses 4,5,6 Gy respectivelycompared to control

    High Resolution Methylome Map of Rat Indicates Role of Intragenic DNA Methylation in Identification of Coding Region

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    DNA methylation is crucial for gene regulation and maintenance of genomic stability. Rat has been a key model system in understanding mammalian systemic physiology, however detailed rat methylome remains uncharacterized till date. Here, we present the first high resolution methylome of rat liver generated using Methylated DNA immunoprecipitation and high throughput sequencing (MeDIP-Seq) approach. We observed that within the DNA/RNA repeat elements, simple repeats harbor the highest degree of methylation. Promoter hypomethylation and exon hypermethylation were common features in both RefSeq genes and expressed genes (as evaluated by proteomic approach). We also found that although CpG islands were generally hypomethylated, about 6% of them were methylated and a large proportion (37%) of methylated islands fell within the exons. Notably, we obeserved significant differences in methylation of terminal exons (UTRs); methylation being more pronounced in coding/partially coding exons compared to the non-coding exons. Further, events like alternate exon splicing (cassette exon) and intron retentions were marked by DNA methylation and these regions are retained in the final transcript. Thus, we suggest that DNA methylation could play a crucial role in marking coding regions thereby regulating alternative splicing. Apart from generating the first high resolution methylome map of rat liver tissue, the present study provides several critical insights into methylome organization and extends our understanding of interplay between epigenome, gene expression and genome stability
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