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Effect of irregularity on the propagation of torsional surface waves in an initially stressed anisotropic poro-elastic layer

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Applied Mathematics and Mechanics(English Edition) 2010年第4期31卷 481-492页

作者： s.gupta A.CHATTOPAdHYAY d.K.MAJHI department of Applied Mathematics Indian School of Mines University

The paper studies the propagation of torsional surface waves in an initially stressed anisotropic poro-elastic layer over a semi-infinite heterogeneous half space with linearly varying rigidity and density due to irregularity at the interface. The irregularity is taken in the half space in the form of a rectangle. It is observed that torsional surface waves propagate in this assumed medium. In the absence of the irregularity, the velocity equation of the torsional surface wave is also obtained. For a layer over a homogeneous half space, the velocity of torsional surface waves coincides with that of the Love waves.

关键词： irregularity torsional surface waves anisotropic initial stress

Influence of linearly varying density and rigidity on torsional surface waves in inhomogeneous crustal layer

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Applied Mathematics and Mechanics(English Edition) 2012年第10期33卷 1239-1252页

作者： s.gupta s.KVIsHWAKARMA d.K.MAJHI s.KUNdU department of Applied Mathematics Indian School of Mines

The present work deals with the possibility of propagation of torsional surface wave in an inhomogeneous crustal layer over an inhomogeneous half space. The layer has inhomogeneity which varies linearly with depth whereas the inhomogeneous half space exhibits inhomogeneity of three types, namely, exponential, quadratic, and hyperbolic discussed separately. The dispersion equation is deduced for each case in a closed form. For a layer over a homogeneous half space, the dispersion equation agrees with the equa- tion of the classical case. It is observed that the inhomogeneity factor due to linear variation in density in the inhomogeneous crustal layer decreases as the phase velocity increases, while the inhomogeneity factor in rigidity has the reverse effect on the phase velocity.

关键词： torsional wave phase velocity crustal layer exponential quadratic,hyperbolic

Effect of rigid boundary on propagation of torsional surface waves inporous elastic layer

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Applied Mathematics and Mechanics(English Edition) 2011年第3期32卷 327-338页

作者： s. gupta A. CHATTOPAdHYAY d. K. MAJHI department of Applied Mathematics Indian School of Mines

The paper presents the effect of a rigid boundary on the propagation of torsional surface waves in a porous elastic layer over a porous elastic half-space using the mechanics of the medium derived by Cowin and Nunziato （Cowin, s. C. and Nunziato, J. W. Linear elastic materials with voids. Journal of Elasticity, 13（2）, 125-147 （1983））. The velocity equation is derived, and the results are discussed. It is observed that there may be two torsional surface wave fronts in the medium whereas three wave fronts of torsional surface waves in the absence of the rigid boundary plane given by dey et al. （dey, s., gupta, s., gupta, A. K., Kar, s. K., and de, P. K. Propagation of torsional surface waves in an elastic layer with void pores over an elastic half-space with void pores. Tamkang Journal of science and Engineering, 6（4）, 241-249 （2003））. The results also reveal that in the porous layer, the Love wave is also available along with the torsional surface waves. It is remarkable that the phase speed of the Love wave in a porous layer with a rigid surface is different from that in a porous layer with a free surface. The torsional waves are observed to be dispersive in nature, and the velocity decreases as the oscillation frequency increases.

关键词： torsional surface wave Love wave rigid boundary porous wave front

Propagation of Love waves in non-homogeneous substratum over initially stressed heterogeneous half-space

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 249-258页

作者： s.gupta d.K.MAJHI s.KUNdU s.K.VIsHWAKARMA department of Applied Mathematics Indian School of Mines

The paper studies the propagation of Love waves in a non-homogeneous substratum over an initially stressed heterogeneous half-space. The dispersion equation of phase velocity is derived. The velocities of Love waves are calculated numerically as a function of kH and presented in a number of graphs, where k is the wave number, and H is the thickness of the layer. The case of Gibson＇s half-space is also considered. It is observed that the speed of Love waves is finite in the vicinity of the surface of the half-space and vanishes as the depth increases for a particular wave number. It is also observed that an increase in compressive initial stresses causes decreases of Love waves velocity for the same frequency, and the tensile initial stress of small magnitude in the half-space causes increase of the velocity.

关键词： Love waves initial stress heterogeneous half-space Gibson's half-space,dispersion equation phase velocity

sources and deficiency diseases of Mineral Nutrients in Human Health and Nutrition:A Review

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Pedosphere 2014年第1期24卷 13-38页

作者： U.C.gupta s.C.gupta Agriculture and Agri-Canada Canada Crops and Livestock Research Centre The department of Plastic surgery Loma Linda University

Mineral nutrients are fundamentally metals and other inorganic compounds. The life cycle of these mineral nutrients begins in soil, their primary source. soil provides minerals to plants and through the plants the minerals go to animals and humans; animal products are also the source of mineral nutrients for humans. Plant foods contain almost all of the mineral nutrients established as essential for human nutrition. They provide much of our skeletal structure, e.g., bones and teeth. They are critical to countless body processes by serving as essential co-factors for a number of enzymes. Humans can not utilize most foods without critical minerals and enzymes responsible for digestion and absorption. Though mineral nutrients are essential nutrients, the body requires them in small, precise amounts. We require them in the form found in crops and they can be classified into three different categories： major, secondary, and micro or trace minerals. This classification is based upon their requirement rather than on their relative importance. Major minerals such as potassium （K） and phosphorus （P） are required in amounts of up to 10 g d-1. The daily requirement of secondary and micro minerals ranges from 400 to 1 500 mg d-1 and 45 ~tg d-1 to 11 mg d-1, respectively. To protect humans from mineral nutrient deficiencies, the key is to consume a variety of foods in modest quantities, such as different whole grains, low fat dairy, and different meats, vegetables and fruits. For insurance purposes, a supplement containing various mineral nutrients can be taken daily.

关键词： deficiency diseases deficiency symptoms origin recommended daily dose toxicity

Role of salivary matrix metalloproteinase-8 （MMP-8） in chronic periodontitis diagnosis

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Frontiers of Medicine 2015年第1期9卷 72-76页

作者： Namita gupta N.d. gupta Akash gupta saif Khan Neha Bansa department of Periodontics and Community dentistry Dr. Z. A. Dental College Aligarh Muslim University Aligarh U.P. India department of Biochemistry Rama Medical College and Hospital Pilakhua Hapur. U.P. India

Periodontitis is an inflammatory disease of the periodontium. Any imbalance between the matrix metalloproteinases （MMPs） secreted by neutrophils and tissue inhibitors initiates the destruction of collagen in gum tissue, leading to chronic periodontitis. This study aimed to correlate salivary levels of MMP-8 and periodontal parameters of chronic periodontitis to establish MMP-8 as a noninvasive marker for the early diagnosis of chronic periodontitis. The study involved 40 subjects visiting the periodontic OPd of dr. Ziauddin Ahmad dental College and Hospital, located in Aligarh, U.P., India, from 2011 to 2012. The subjects were divided into two groups： group I consisted of 20 periodontally healthy subjects （controls） while group II consisted of 20 patients with chronic periodontitis. Chronic periodontitis was assessed on the basis of several periodontal parameters, including pocket probing depth （PPd）, clinical attachment level （CAL）, gingival index （GI）, and plaque index （PI）. Around 3 ml of unstimulated and whole expectorated saliva was collected for MMP-8 estimation by ELIsA using Quantikine human total MMP-8 immunoassay kits. data were analyzed using sTATIsTICA （Windows version 6） software. salivary MMP-8 levels of groups I and II were 190.91 ± 143.89 ng/ml and 348.26± 202.1 ng/ml, respectively. The MMP-8 levels and periodontal status （PPd, CAL, GI, and PI） of groups I and II showed positive and significant correlations （for PPd, r = 0.63, P 〈 0.001; for CAL, r = 0.54, P 〈 0.001; for GI, r = 0.49, P 〈 0.001; and for PI, r = 0.63, P 〈 0.001）. The results of this study demonstrate elevated concentrations of MMP-8 in individuals with chronic periodontitis.

关键词： matrix metalloproteinase-8 chronic periodontitis pocket probing depth clinical attachment level gingival index plaque index

distilling physical origins of hardness in multi-principal element alloys directly from ensemble neural network models

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npj Computational Materials 2022年第1期8卷 1450-1460页

作者： d.Beniwal P.singh s.gupta M.J.Kramer d.d.Johnson P.K.Ray Metallurgical&Materials Engineering Indian Institute of Technology RoparRupnagar140001PunjabIndia Ames Laboratory US Department of EnergyAmesIA50011USA Materials science&Engineering Iowa State UniversityAmesIA50011USA

despite a plethora of data being generated on the mechanical behavior of multi-principal element alloys,a systematic assessment remains inaccessible via Edisonian *** approach this challenge by considering the specific case of alloy hardness,and present a machine-learning framework that captures the essential physical features contributing to hardness and allows high-throughput exploration of multi-dimensional compositional *** model,tested on diverse datasets,was used to explore and successfully predict hardness in Al_(x)Ti_(y)(CrFeNi)_(1-x-y),Hf_(x)Co_(y)(CrFeNi)_(1-x-y)and Al_(x)(TiZrHf)_(1-x)systems supported by data from density-functional theory predicted phase stability and ordering *** experimental validation of hardness was done on *** selected systems pose diverse challenges due to the presence of ordering and clustering pairs,as well as vacancy-stabilized novel *** also present a detailed model analysis that integrates local partial-dependencies with a compositional-stimulus and model-response study to derive material-specific insights from the decision-making process.

关键词： alloys alloy element

Microstructural image based convolutional neural networks for efficient prediction of full-field stress maps in short fiber polymer composites

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defence Technology（防务技术） 2023年第6期24卷 58-82页

作者： s.gupta T.Mukhopadhyay V.Kushvaha department of Civil Engineering Indian Institute of Technology JammuJ&KIndia department of Aerospace Engineering Indian Institute of Technology KanpurUPIndia

The increased demand for superior materials has highlighted the need of investigating the mechanical properties of composites to achieve enhanced constitutive ***-reinforced polymer composites have emerged as an integral part of materials development with tailored mechanical ***,the complexity and heterogeneity of such composites make it considerably more challenging to have precise quantification of properties and attain an optimal design of structures through experimental and computational *** order to avoid the complex,cumbersome,and labor-intensive experimental and numerical modeling approaches,a machine learning(ML)model is proposed here such that it takes the microstructural image as input with a different range of Young’s modulus of carbon fibers and neat epoxy,and obtains output as visualization of the stress component s11(principal stress in the x-direction).For obtaining the training data of the ML model,a short carbon fiberfilled specimen under quasi-static tension is modeled based on 2d Representative Area Element(RAE)using finite element *** composite is inclusive of short carbon fibers with an aspect ratio of 7.5that are infilled in the epoxy systems at various random orientations and positions generated using the simple sequential Inhibition(ssI)*** study reveals that the pix2pix deep learning Convolutional Neural Network(CNN)model is robust enough to predict the stress fields in the composite for a given arrangement of short fibers filled in epoxy over the specified range of Young’s modulus with high *** CNN model achieves a correlation score of about 0.999 and L2 norm of less than 0.005 for a majority of the samples in the design spectrum,indicating excellent prediction *** this paper,we have focused on the stage-wise chronological development of the CNN model with optimized performance for predicting the full-field stress maps of the fiber-reinforced composite ***

关键词： Micromechanics of fiber-reinforced composites Machine learning assisted stress prediction Microstructural image-based machine learning CNN based stress analysis

Non-alcoholic fatty liver disease may not be a severe disease at presentation among Asian Indians

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World Journal of Gastroenterology 2006年第21期12卷 3400-3405页

作者： Kaushal Madan Yogesh Batra s d.tta gupta Bal Chander K d Anand Rajan M s Tewatia s K Panda s K Acharya department of Gastroenterology All India Institute of Medical sciences New DelhiIndia department of Gastroenterology All India Institute of Medical sciences New DelhiIndia Department of PathologyAll India Institute of Medical SciencesNew DelhiIndia department of Pathology All India Institute of Medical sciences New DelhiIndia

AIM： To evaluate the clinical and biochemical profile of patients with non alcoholic fatty liver disease （NAFLd） and to assess their histological severity at ***： Consecutive patients presenting to the liver clinic of All India Institute of Medical sciences （AIIMs） with raised transaminases to at least 1.5 times upper limit of normal, and histologically confirmed non-alcoholic fatty liver disease were included. Patients who had significant alcohol intake or positive markers of other liver diseases or who were taking drugs known to produce fatty liver were excluded. The clinical, biochemical and histological profile of this group was studied. REsULTs： Fifty-one patients with NAFLd formed the study population. Their median age and BMI were 34（17-58） years and 26.7（21.3-32.5） kg/m^2 respectively and 46 （90.1%） were males. The majority of the patients had mild inflammation, either grade 1 [32 （63%）] or grade 2 [16 （31%）] and only 3 （6%） patients had severe （grade 3） inflammation. Twenty-three （45%）, 19 （37%）, 8（16%） and 1（2%） patient had stage 0, 1, 2 and 3 fibrosis respectively on index biopsy and none had cirrhosis. On univariate analysis, triglyceride levels more than 150 mg % （OR = 7.1; 95% CI： 1.6-31.5, P = 0.002） and AsT ALT ratio 〉 1 （OR = 14.3; 95% CI： 1.4-678.5, P = 0.008） were associated with high grades of inflammation and none was associated with advanced fibrosis. On multivariate logistic regression analysis, hypertriglyceridemia 〉150 mg% was the only factor independently associated with presence of high grade of inflammation （OR = 1.6; 95% CI： 1.3-22.7, P =0.02）, while none was associated with advanced fibrosis. Triglyceride levels correlated positively with inflammatory grade （r = 0.412; P = 0.003）. CONCLUsION： NAFLd in North Indian patients is a disease of young over-weight males, most of whom are insulin resistant and they tend to have a mild histological disease at presentation.

关键词： Inflammation Fibrosis Triglycerides Non alcoholic steatohepatitis