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Topological Studies of Three-dimensional Flows in a High Pressure Compressor Stator Blade Row without and with Boundary Layer Aspiration

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Chinese Journal of Aeronautics 2011年第5期24卷 541-549页

作者： ankit SACHDEVA Francis LEBOEUF Laboratoire de Mécanique des Fluides et d'Acoustique Ecole Centrale de Lyon

This paper presents a numerical study of the flow topologies of three-dimensional （3D） flows in a high pressure compressor stator blade row without and with boundary layer aspiration on the hub wall. The stator blade is representative of the first stage operating under transonic inlet conditions and the blade design encourages development of highly complex 3D flows. The blade has a small tip clearance. The computational fluid dynamics （CFD） studies show progressive increase of hub corner stall with the increase in incidence. Aspiration is implemented on the hub wall via a slot in the comer between the hub wall and the suction surface. The CFD studies show aspiration to be sensitive to the suction flow rate; lower rate leads to very complex flow struc- tures and increased level of losses whereas higher rate renders aspiration effective for control of hub comer separation. The flow topologies are studied by trace of skin friction lines on the walls. The nature of flow can be explained by the topological rules of closed separation. Furthermore, a deeper analysis is done for a particular case with advanced criterion to test the non-degeneracy of critical points in the flow field.

关键词： high pressure compressor flow topologies three-dimensional flows boundary layer aspiration tip clearance

Elastic metamaterials and dynamic homogenization: a review

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International Journal of Smart and Nano Materials 2015年第1期6卷 41-60页

作者： ankit Srivastava Department of Mechanical Materialsand Aerospace EngineeringIllinois Institute of TechnologyChicagoIL 60616USA

In this paper,we review the recent advances which have taken place in the understanding and applications of acoustic/elastic *** are artificially created composite materials which exhibit unusual properties that are not found in *** begin with presenting arguments from discrete systems which support the case for the existence of unusual material properties such as tensorial and/or negative *** arguments are then extended to elastic continuums through coherent averaging *** resulting coupled and nonlocal homogenized relations,called the Willis relations,are presented as the natural description of inhomogeneous *** are specialized to Bloch waves propagating in periodic composites and we show that the Willis properties display the unusual behavior which is often required in metamaterial applications such as the Veselago *** finally present the recent advances in the area of transformation elastodynamics,charting its inspirations from transformation optics,clarifying its particular challenges,and identifying its connection with the constitutive relations of the Willis and the Cosserat types.

关键词： metamaterials dynamic homogenization periodic composites cloaking

Kinematic Modeling for Biped Robot Gait Trajectory Using Machine Learning Techniques

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Journal of Bionic Engineering 2022年第2期19卷 355-369页

作者： Bharat Singh ankit vijayvar.iya Rajesh Kumar Department of Electrical Engineering Malaviya National Institute of TechnologyJaipur 302017India

This paper presents the predictive models for biped robot trajectory *** models are parametrizing as a continuous function of joint angle *** a previous work,the authors had collected the human locomotion dataset at RAMAN Lab,MNIT,Jaipur,*** MNIT gait dataset consists of walking data on a plane surface of 120 human subjects from different age groups and ***-two machine learning models(linear,support vector,k-nearest neighbor,ensemble,probabilistic,and deep learning)trained using the collected *** addition,two types of mapping,(a)one-to-one and(b)many-to-one,are presented for each *** mapping models act as a reference policy for the control of joints and prediction of state for the next time instant in advance if the onboard sensor *** show that the deep learning and probabilistic learning models perform better for both types of ***,the probabilistic model outperforms the deep learning-based models in terms of maximum error,because the probabilistic model effectively deals with the prediction *** addition,many-to-one outperforms the one-to-one mapping because it captures the correlation between knee,hip,and ankle ***,this study suggests a many-to-one mapping using the probabilistic model for biped robot trajectory generation.

关键词： Kinematic Locomotion Machine learning Prediction Regression

Effect of Biogas Digested Liquid on CH_4 and N_2O Flux in Paddy Ecosystem

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Journal of Integrative Agriculture 2014年第3期13卷 635-640页

作者： ankit Singla Kazuyuki Inubushi Bioresource Science Graduate School of Horticulture Chiba University

Biogas production generates digested slurry as a byproduct. It can be used as a fertilizer especially after its conversion into digested liquid. A pot based study was conducted in order to evaluate the effect of the application of digested liquid on CH4 and N2O flux, and plant biomass in paddy. Analysis revealed that digested liquid treated soils released more CH4 compared to ammonium sulphate and the control. Ammonium sulphate treated soil emitted the highest N20 whereas digested liquid application decreased its emission significantly. Further, the cumulative emission over 101 d of the experiment was found to be higher for CHa （16.9 to 29.9 g m^-2） compared to N20 （-49.3 to 18.9 mg m^-2） for all treatments. Digested liquid application had positive impact on plant variables such as panicle number and weight of panicles. This study suggests that digested liquid application significantly decrease N20 emission and increase CH4 emission possibly due to affecting the availability of organic C in the soil to microbial activity for methanogenesis. Another possibility for enhancing CH4 emission by following biogas digested liquid could be attributed to the increase in plant biomass.

关键词： biogas digested liquid paddy ammonium sulphate CH4 N20 plant biomass

Stability and Bifurcation of a Prey-Predator System with Additional Food and Two Discrete Delays

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Computer Modeling in Engineering & Sciences 2021年第2期126卷 505-547页

作者： ankit Kumar Balram Dubey Department of Mathematics BITS PilaniPilani CampusPilani333031India

In this paper,the impact of additional food and two discrete delays on the dynamics of a prey-predator model is *** interaction between prey and predator is considered as Holling Type-II functional *** additional food is provided to the predator to reduce its dependency on the *** delay is the gestation delay in predator while the other delay is the delay in supplying the additional food to *** positivity,boundedness and persistence of the solutions of the system are studied to show the system as biologically *** existence of steady states,their local and global asymptotic behavior for the non-delayed system are *** is shown that(i)predator’s dependency factor on additional food induces a periodic solution in the system,and(ii)the two delays considered in the system are capable to change the status of the stability behavior of the *** existence of periodic solutions via Hopf-bifurcation is shown with respect to both the *** analysis shows that both delay parameters play an important role in governing the dynamics of the *** direction and stability of Hopf-bifurcation are also investigated through the normal form theory and the center manifold *** experiments are also conducted to validate the theoretical results.

关键词： predator delay system

Optimizing submerged arc welding using response surface methodology, regression analysis, and genetic algorithm

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Defence Technology（防务技术） 2018年第3期14卷 204-212页

作者： Ajitanshu Vedrtnam Gyanendra Singh ankit Kumar Department of Mechanical Engineering Invertis University Department of Applied Mechanics Motilal Nehru National Institute of Technology Allahabad

The weld quality is significantly affected by the weld parameters(arc voltage, welding current, nozzle to plate distance and welding speed) in the submerged arc welding(SAW). Bead-on-plate welds were performed on stainless steel plates by automated SAW machine. The experimental data were collected in accordance with the response surface methodology(RSM). In addition to RSM, the regression analysis was performed to set up inputeoutput relationships in the SAW process. It was found that weld parameters define the geometry of weld bead and determine the mechanical properties of the joint. The influence of the input variables on weld bead geometry is represented as graphs. It was found that an increment in voltage increases the bead width but decreases the bead height, whereas the current increment result-in an increment in bead height and no change in bead width. The bead width and height decrease with the increment in the welding speed. With an increment in the nozzle-to-plate distance, bead width decrease, but bead height increases. The value of bead hardness increases with the increment in current but the increment in voltage and travel speed does not have a significant influence on the bead hardness. The predictions from the mathematical model developed and the corresponding experimental results are having a fair agreement. Further, the genetic algorithm(GA) is also used for predicting the weld bead geometry.

关键词：回归分析基因算法方法论表面反应弧焊沉没焊接参数

Broadband, High Gain, Narrow Width Rectangular Dielectric Resonator Antenna with Air Gap

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Journal of Electronic Science and Technology 2019年第1期17卷 90-96页

作者： ankit Kumar Roy Sukla Basu Kalyani Government Engineering College

The broadband, narrow width, rectangular dielectric resonator antenna(RDRA) of aluminum nitride(εr=8.6) was designed and the effect of inclusion of air gap at the bottom of the dielectric resonator antenna(DRA),above the ground plane, was investigated. Gain around 7 dBi was obtained for DRA with air gap(DRAAG) over a broad bandwidth in upper X, Ku, and K bands. Further enhancement in gain could be obtained by placing a metal wall parallel to the length of DRA. However, due to the presence of metal wall, bandwidth was reduced. These structures with the metal wall are capable of operating over a wide band extending from Ku band to lower K band with the gain of around 10 dBi. CST Microwave Studio Software was used to simulate all these *** parameters of DRA with air gap were compared with several broadband DRA structures reported in recent literature. The proposed DRAAG with the metal wall in this paper is capable of operating over a wide bandwidth along with a significant gain.

关键词： Dielectric resonator antenna(DRA) rectangular dielectric resonator antenna(RDRA) wide band dielectric resonator antenna X Ku and K bands dielectric resonator antenna

A multicountry comparison of cryptocurrency vs gold: Portfolio optimization through generalized simulated annealing

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Blockchain(Research and Applications) 2022年第3期3卷 23-35页

作者： ankit Som Parthajit Kayal Madras School of Economics Chennai600025India

The last few years have seen a paradigm shift in the financial sector with the development of cryptocurrencies as an alternative mode of payment as well as an investment *** aim of this study is *** first is to quantify the volatility of cryptocurrencies in terms of the dynamics of tail-end behavior using different approaches and choose the one with the lowest *** second is to investigate the effect of its inclusion in a portfolio with and without gold,to see if Bitcoin is indeed the“digital gold”.This paper uses the generalized simulated annealing optimization technique to compare portfolios for ten countries across the *** data provide convincing evidence in favor of the inclusion of Bitcoin in the optimized ***-window analyses(three-year and five-year)confirm the ***,for some countries,the empirical pattern suggests that instead of replacing gold from the portfolio,both should be *** results are robust in terms of the inclusion of non-linear constraints.

关键词： Cryptocurrency Gold Value-at-risk Portfolio optimization Generalized simulated annealing

RSPO2 as Wnt signaling enabler: Important roles in cancer development and therapeutic opportunities

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Genes & Diseases 2024年第2期11卷 788-806页

作者： ankit Srivastava Deeksha Rikhari Sameer Srivastava Department of Biotechnology Motilal Nehru National Institute of TechnologyAllahabadUttar Pradesh 211004India

R-spondins are secretory proteins localized in the endoplasmic reticulum and Golgi bodies and are processed through the secretory *** the R-spondin family,RSPO2 has emanated as a novel regulator of Wnt signaling,which has now been acknowledged in numerous in vitro and in vivo *** is an abnormal growth of cells that proliferates and spreads uncontrollably due to the accumulation of genetic and epigenetic factors that constitutively activate Wnt signaling in various types of *** cancer (CRC) begins when cells in the colon and rectum follow an indefinite pattern of division due to aberrant Wnt activation as one of the key ***-long progress in research on R-spondins has demonstrated their oncogenic function in distinct cancer types,particularly *** a critical regulator of the Wnt pathway,it modulates several phenotypes of cells,such as cell proliferation,invasion,migration,and cancer stem cell ***,RSPO mutations,gene rearrangements,fusions,copy number alterations,and altered gene expression have also been identified in a variety of cancers,including *** this review,we addressed the recent updates regarding the recurrently altered R-spondins with special emphasis on the RSPO2 gene and its involvement in potentiating Wnt signaling in *** addition to the compelling physiological and biological roles in cellular fate and regulation,we propose that RSPO2 would be valuable as a potential biomarker for prognostic,diagnostic,and therapeutic use in CRC.

关键词： CRC Gene fusion R-Spondins RSPO2 Therapeutics Wnt signaling