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Measurement of bit-rock interface temperature and wear rate of the tungsten carbide drill bit during rotary drilling

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Friction 2020年第6期8卷 1073-1082页

作者： Vijay Kumar shankar Bijay Mihir KUNAR Chivukula Suryanarayana MURTHY M R RAMESH Department of Mining Engineering National Institute of Technology KarnatakaSurathkal 575025India Department of Mechanical Engineering National Institute of Technology KarnatakaSurathkal 575025India

Rock drilling is an essential operation in mining industries.Temperature at the bit-rock interface plays a major role in the wear rate of the drill bit.This paper primarily focuses on the wear rate of tungsten carbide(WC)drill bit and the interrelationship between temperature and wear rate during rotary drilling operations conducted using a computer numerical control(CNC)machine.The interrelationship between the temperature and wear rate was studied with regard to three types of rock samples,i.e.,fine-grained sandstone(FG)of uniaxial compressive strength(UCS)that is 17.83 MPa,medium-grained sandstone(MG)of UCS that is 13.70 MPa,and fine-grained sandstone pink(FGP)of UCS that is 51.67 MPa.Wear rate of the drill bit has been measured using controlled parameters,i.e.,drill bit diameter(6,8,10,12,and 16 mm),spindle speed(250,300,350,400,and 450 rpm),and penetration rate(2,4,6,8,and 10 mm/min),respectively.Further,a fully instrumented laboratory drilling set-up was utilized.The weight of each bit was measured after the bit reached 30 mm depth in each type of the rock sample.Furthermore,effects of the bit-rock interface temperature and operational parameters on wear rate of the drill bits were examined.The results show that the wear rate of drill bits increased with an increase in temperature for all the bit-rock combinations considered.This is due to the silica content of the rock sample,which leads to an increase in the frictional heat between the bit-rock interfaces.However,in case of medium-grained sandstone,the weight percentage(wt%)of SiO2 is around 7.23 wt%,which presents a very low wear rate coefficient of 6.33×10^–2 mg/(N?m).Moreover,the temperature rise during drilling is also minimum,i.e.,around 74℃,in comparison to that of fine-grained sandstone and fine-grained sandstone pink.In addition,this paper develops the relationship between temperature and wear rate characteristics by employing simple linear regression analysis.

关键词： temperature wear rate drilling simple linear regression

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Role of Pathogen-Related Protein 10 (PR 10) under Abiotic and Biotic Stresses in Plants

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Phyton-International Journal of Experimental Botany 2020年第2期89卷 167-182页

作者： Rakesh Kumar Sinha Shiv shankar Verma Anshu Rastogi Department of Plant Biophysics&Biochemistry Biology Center of the Czech Academy of SciencesInstitute of PlantMolecular BiologyCeskeBudejovice37005Czech Republic School of Medicine Case Western Reserve UniversityCleveland44106USA Department of Ecology and Environmental Protection Laboratory of BioclimatologyPoznan University of Life SciencesPoznan60-649Poland

Members of the Pathogenesis Related(PR)10 protein family have been identified in a variety of plant species and a wide range of functions ranging from defense to growth and development has been attributed to them.PR10 protein possesses ribonuclease(RNase)activity,interacts with phytohormones,involved in hormone-mediated signalling,afforded protection against various phytopathogenic fungi,bacteria,and viruses particularly in response to biotic and abiotic stresses.The resistance mechanism of PR10 protein may include activation of defense signalling pathways through possible interacting proteins involved in mediating responses to pathogens,degradation of RNA of the invading pathogens.Moreover,several morphological changes have been shown to accompany the enhanced abiotic stress tolerance.In this review,the possible mechanism of action of PR10 protein against biotic and abiotic stress has been discussed.Furthermore,our findings also confirmed that the in vivo Nitric oxide(NO)is essential for most of environmental abiotic stresses and disease resistance against pathogen infection.The proper level of NO may be necessary and beneficial,not only in plant response to the environmental abiotic stress,but also to biotic stress.The updated information on this interesting group of proteins will be useful in future research to develop multiple stress tolerance in plants.

关键词： Pathogenesis-related(PR) PR10 abiotic stress biotic stress ribonuclease stress tolerance nitric oxide

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Stability of fluid flow in a Brinkman porous medium–A numerical study

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Journal of Hydrodynamics 2014年第5期26卷 681-688页

作者： shankar B.M. KUMAR Jai SHIVAKUMARA I.S. 吴朝安 Department of Mathematics PES Institute of TechnologyBangalore 560 085India ISRO Satellite Centre Bangalore 560 017India Department of Mathematics Bangalore UniversityBangalore 560 001India Department of Mechanical Engineering The University of Hong Kong

The stability of fluid flow in a horizontal layer of Brinkman porous medium with fluid viscosity different from effective viscosity is investigated. A modified Orr-Sommerfeld equation is derived and solved numerically using the Chebyshev collocation method. The critical Reynolds number Re, the critical wave number ac and the critical wave speed cc are computed for various values of porous parameter and ratio of viscosities. Based on these parameters, the stability characteristics of the system are discussed in detail. Streamlines are presented for selected values of parameters at their critical state.

关键词： Brinkman model Chebyshev collocation method hydrodynamic stability modified Orr-Sommerfeld equation

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Improvement of the prediction performance of a soft sensor model based on support vector regression for production of ultra-low sulfur diesel

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Petroleum Science 2015年第1期12卷 177-188页

作者： Saeid Shokri Mohammad Taghi Sadeghi Mahdi Ahmadi Marvast shankar Narasimhan Department of Chemical Engineering Iran University of Science and Technology (IUST) Process and Equipment Technology Development Division Research Institute of Petroleum Industry (RIPI) Department of Chemical Engineering

A novel data-driven, soft sensor based on support vector regression （SVR） integrated with a data compression technique was developed to predict the product quality for the hydrodesulfurization （HDS） process. A wide range of experimental data was taken from a HDS setup to train and test the SVR model. Hyper-parameter tuning is one of the main challenges to improve predictive accuracy of the SVR model. Therefore, a hybrid approach using a combination of genetic algorithm （GA） and sequential quadratic programming （SQP） methods （GA-SQP） was developed. Performance of different optimization algorithms including GA-SQP, GA, pattern search （PS）, and grid search （GS） indicated that the best average absolute relative error （AARE）, squared correlation coefficient （R2）, and computation time （CT）（AARE = 0.0745, R2 = 0.997 and CT = 56 s） was accomplished by the hybrid algorithm. Moreover, to reduce the CT and improve the accuracy of the SVR model, the vector quantization （VQ） technique was used. The results also showed that the VQ technique can decrease the training time and improve prediction performance of the SVR model. The proposed method can provide a robust, soft sensor in a wide range of sulfur contents with good accuracy.

关键词： Soft sensor Support vector regression Hybrid optimization method Vector quantization Petroleum refinery Hydrodesulfurization process Gas oil

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Investigations on tribo-mechanical behaviour of Al-Si10-Mg/sugarcane bagasse ash/SiC hybrid composites

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China Foundry 2019年第4期16卷 277-284页

作者： shankar Subramanian Balaji Arunachalam Kawin Nallasivam Alokesh Pramanik Department of Mechatronics Engineering Kongu Engineering College Erode - 638060 TamilNadu India Department of Mechanical Engineering Kongu Engineering College Erode - 638060 TamilNadu India School of Civil and Mechanical Engineering Curtin University Bentley WA Australia

The effect of mechanical and tribological behaviour of aluminium alloy(Al-Si10-Mg) with sugarcane bagasse ash and silicon carbide reinforced metal matrix composites were investigated. Al-Si10-Mg alloy reinforced with 9 wt.% of treated sugarcane bagasse ash particles of size(< 75 μm) and 0 wt.%, 3 wt.%, 6 wt.% and 9 wt.% of silicon carbide particles of size(< 25 μm) were fabricated using the stir casting method. Morphological analysis was done using scanning electron microscopy to access the distribution of reinforcement particles in the matrix alloy. Tensile, hardness, and impact strengths were increased with an increase in weight fraction of SiC reinforcement particles in the aluminium alloy, while the ductility was decreased. Pin-on-disc dry sliding wear test was carried out with 10, 20 and 30 N loads with a sliding speed of 10 m·s-1 for a constant time period of 20 min to predict the wear behaviour of the developed composites. Worn surfaces of the wear-tested specimens and fracture morphology structure of the tensile-tested specimens were analysed. Results show that the composites reinforced with sugarcane bagasse ash and silicon carbide particles exhibit superior wear resistance.

关键词： aluminium alloy sugarcane bagasse ash silicon carbide mechanical properties wear fracture morphology

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An IoT-Cloud Based Intelligent Computer-Aided Diagnosis of Diabetic Retinopathy Stage Classification Using Deep Learning Approach

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Computers, Materials & Continua 2021年第2期66卷 1665-1680页

作者： K.shankar Eswaran Perumal Mohamed Elhoseny Phong Thanh Nguyen Department of Computer Applications Alagappa UniversityKaraikudi630001India Faculty of Computers and Information Mansoura UniversityMansoura35516Egypt Department of Project Management Ho Chi Minh City Open UniversityHo Chi Minh City7000000Vietnam

Diabetic retinopathy(DR)is a disease with an increasing prevalence and the major reason for blindness among working-age population.The possibility of severe vision loss can be extensively reduced by timely diagnosis and treatment.An automated screening for DR has been identified as an effective method for early DR detection,which can decrease the workload associated to manual grading as well as save diagnosis costs and time.Several studies have been carried out to develop automated detection and classification models for DR.This paper presents a new IoT and cloud-based deep learning for healthcare diagnosis of Diabetic Retinopathy(DR).The proposed model incorporates different processes namely data collection,preprocessing,segmentation,feature extraction and classification.At first,the IoT-based data collection process takes place where the patient wears a head mounted camera to capture the retinal fundus image and send to cloud server.Then,the contrast level of the input DR image gets increased in the preprocessing stage using Contrast Limited Adaptive Histogram Equalization(CLAHE)model.Next,the preprocessed image is segmented using Adaptive Spatial Kernel distance measure-based Fuzzy C-Means clustering(ASKFCM)model.Afterwards,deep Convolution Neural Network(CNN)based Inception v4 model is applied as a feature extractor and the resulting feature vectors undergo classification in line with the Gaussian Naive Bayes(GNB)model.The proposed model was tested using a benchmark DR MESSIDOR image dataset and the obtained results showcased superior performance of the proposed model over other such models compared in the study.

关键词： Deep learning classification GaussianNaive Bayes feature extraction diabetic retinopathy

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Prevalence of intellectual disability in India:A meta-analysis

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World Journal of Clinical Pediatrics 2022年第2期11卷 206-214页

作者： Paul Swamidhas Sudhakar Russell Sahana Nagaraj Ashvini Vengadavaradan Sushila Russell Priya Mary Mammen Satya Raj shankar Shonima Aynipully Viswanathan Richa Earnest Swetha Madhuri Chikkala Grace Rebekah Child and Adolescent Psychiatry Unit Christian Medical CollegeVellore 632002Tamil NaduIndia Department of Psychiatry Christian Medical CollegeVellore 632002Tamil NaduIndia Department of Biostatistic Christian Medical CollegeVellore 632002Tamil NaduIndia

BACKGROUND Burden due to intellectual disability(ID) is only third to the depressive disorders and anxiety disorders in India. This national burden significantly contributes to the global burden of ID and hence one has to think globally and act locally to reduce this burden. At its best the collective prevalence of ID is in the form of narrative reviews. There is an urgent need to document the summary prevalence of ID to enhance further policymaking, national programs and resource allocation.AIM To establish the summary prevalence of ID during the past 60 years in India.METHODS Two researchers independently and electronically searched Pub Med, Scopus, and the Cochrane library from January 1961 to December 2020 using appropriate search terms. Two other investigators extracted the study design, setting, participant characteristics, and measures used to identify ID. Two other researchers appraised the quality of the studies using the Joanna Briggs Institute critical appraisal format for Prevalence Studies. Funnel plot and Egger’s regression test were used to ascertain the publication and small study effect on the prevalence. To evaluate the summary prevalence of ID, we used the random effects model with arcsine square-root transformation. Heterogeneity of I^(2)≥ 50% was considered substantial and we determined the heterogeneity with meta-regression. The analyses were performed using STATA(version 16).RESULTS Nineteen studies were included in the meta-analysis. There was publication bias;the trim-and-fill method was used to further ascertain bias. Concerns with control of confounders and the reliable measure of outcome were noted in the critical appraisal. The summary prevalence of ID was 2% [(95%CI: 2%, 3%);I^(2)= 98%] and the adjusted summary prevalence was 1.4%. Meta-regression demonstrated that age of the participants was statistically significantly related to the prevalence;other factors did not influence the prevalence or heterogeneity.CONCLUSION The summary prevalence of ID in India was established to be 2% ta

关键词： India Intellectual disability Prevalence Children and adolescents Meta-analysis

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Potential groundwater recharge zones within New Zealand

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Geoscience Frontiers 2019年第3期10卷 1065-1072页

作者： Shailesh Kumar Singh Malte Zeddies Ude shankar George A.Griffiths National Institute of Water and Atmospheric Research

Water resources in New Zealand are not evenly distributed across the country which makes it difficult to adequately allocate the use of water resources in every basin. Groundwater is a fundamental water resource in New Zealand for agricultural, industrial and domestic use. Detailed knowledge regarding groundwater recharge potential is a pre-requisite for sustainable groundwater management, including the assessment of its vulnerability to contamination by pollutants. In this study, a comprehensive GIS approach was used to map the potential groundwater recharge zones across New Zealand. National data sets of lithology, slope, aspect, land use, soil drainage and drainage density were converted to raster data sets with a spatial resolution of 500 m x 500 m and superimposed to derive groundwater potential zones. The resultant maps demonstrate that the potential is low in urban and mountainous areas, such as the Southern Alps, whereas the highest potential can be found in regions with large lakes and in the lower elevation plains areas, where Quaternary sediments prevail. The resulting maps can be used to identify areas of high nutrient leaching in zones where high groundwater recharge potential exists.

关键词： GIS Potential groundwater recharge map New Zealand

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Microbial cells as biological factory for nanoparticle synthesis

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Frontiers of Materials Science 2021年第2期15卷 177-191页

作者： Bhabani shankar DAS Ankita DAS Abhisek MISHRA Manoranjan ARAKHA Centre for Biotechnology School of Pharmaceutical SciencesSiksha'O'Anusandhan(Deemed to be University)Bhubaneswar 751003OdishaIndia Symbiosis Institute of Health Sciences(SIHS) Symbiosis International(Deemed University)PuneMaharashtraIndia Biological E Limited ShameerpetHyderabadIndia

In present scenario,nanoscience and nanotechnology have drawn the attention of scientist and researchers as leading source of technology with a wide range of useful applications like pharmaceuticals,electronics,biotechnology,biomedicine,wastewater treatment,space technology,industries and medical sciences[1].The physico-chemical characteristics of nanomaterial could make them an ideal material for various applications.Viewing this revolutionary effect,Norio Taniguchi,a famous scientist in 1974 coined the term‘nanotechnology’[2].

关键词： nanotechnology synthesis wastewater

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Weakly nonlinear stability analysis of triple diffusive convection in a Maxwell fluid saturated porous layer

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Applied Mathematics and Mechanics(English Edition) 2018年第2期39卷 153-168页

作者： K.R.RAGHUNATHA I.S.SHIVAKUMARA B.M.shankar Department of Mathematics Bangalore University Department of Mathematics PES University

The weakly nonlinear stability of the triple diffusive convection in a Maxwell fluid saturated porous layer is investigated. In some cases, disconnected oscillatory neutral curves ave found to exist, indicating that three critical thermal Darcy-Rayleigh numbers are required to specify the linear instability criteria. However, another distinguishing feature predicted from that of Newtonian fluids is the impossibility of quasi-periodic bifurcation from the rest state. Besides, the co-dimensional two bifurcation points are located in the Darcy-Prandtl number and the stress relaxation parameter plane. It is observed that the value of the stress relaxation parameter defining the crossover between stationary and oscillatory bifurcations decreases when the Darcy-Prandtl number increases. A cubic Landau equation is derived based on the weakly nonlinear stability analysis. It is found that the bifurcating oscillatory solution is either supercritical or subcritical, depending on the choice of the physical parameters. Heat and mass transfers are estimated in terms of time and area-averaged Nusselt numbers.

关键词： Maxwell fluid triple diffusive convection nonlinea~ stability bifurcation,heat and mass transfer

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