241 results on '"Ashutosh Srivastava"'
Search Results
52. Simulation Study of Charge Plasma Nanotube FET for Low Power Mixed Signal Circuit in IoT Applications
- Author
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Rakesh Kumar, Pothaknuri Manasa, and Ashutosh Srivastava
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- 2022
53. Geographic and Reactive Routing Protocols for MANET.
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Ashutosh Srivastava, Deepak Kumar 0003, and Suresh C. Gupta
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- 2013
- Full Text
- View/download PDF
54. Routing in Ad Hoc Networks under Reference Point Group Mobility.
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Deepak Kumar 0003, Ashutosh Srivastava, and Suresh C. Gupta
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- 2013
- Full Text
- View/download PDF
55. BIPLOT ANALYSIS FOR IDENTIFICATION OF SUPERIOR GENOTYPES IN A RECOMBINANT INBRED POPULATION OF WHEAT UNDER RAINFED CONDITIONS
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Mayank Anand Gururani, Ashutosh Srivastava, R S Sarlach, and Puja Srivastava
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General Veterinary ,Biplot ,business.industry ,food and beverages ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Biotechnology ,law.invention ,Inbred population ,law ,Genotype ,Recombinant DNA ,Identification (biology) ,General Agricultural and Biological Sciences ,business - Abstract
Physiological traits of wheat genotypes and their trait relation to drought conditions are important to identify the genotype in target environments. Thus, genotype selection should be based on multiple physiological traits in variable environments within the target region. This study was conducted at Punjab Agricultural University during rabi crop seasons 2012-13 and 2013-14 to study the recombinant inbred lines (RILs) of wheat genotypes derived from traditional landraces and modern cultivars (C518/2*PBW343) based on various morpho-physiological traits. A total of 175 RILs were selected for this study based on various tolerance indices. The genotype by trait (GT) biplot analysis was applied to data from seven high-yielding RILs grown under irrigated (E1) and rainfed environments (E2). The GGE biplot explained 100% of the total variation for chlorophyll content, grain filling period, peduncle length, water-soluble carbohydrates, grain number, grain yield, and 95.1% for canopy temperature, 94.9% for thousand-grain weight. GT-biplots indicated that the relationships among the studied traits were not consistent across environments, but they facilitated visual genotype comparisons and selection in each environment. RIL 84 and RIL108 were close to the average environment (ideal genotype) for all traits studied except chlorophyll content. A well-performing genotype with great environmental stability is called an "ideal genotype. Among all entries, these genotypes performed well. Therefore, among the traits studied, grain filling period, peduncle length, canopy temperature, water soluble carbohydrates, and 1000 grain weight contributed to grain yield under a stress environment. Furthermore, it may be used as a donor material in breeding programs and QTLs mapping.
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- 2021
56. Role of Arbuscular Mycorrhizal Fungi in Horticultural Crops
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Hari Kesh, Ashutosh Srivastava, and Prashant Kaushik
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- 2022
57. Triple Cavity Backed SIW Slot Antenna for X-Band Mobile Communication and Applications
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Ashutosh Srivastava
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- 2022
58. A Conical Strip-Helical Antenna for Upper Mid-Band Spectrum of 5G
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Ashutosh Srivastava
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- 2022
59. Coexistence of delay-based TCP congestion control: Challenges and opportunities
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Ashutosh Srivastava, Fraida Fund, and Shivendra S. Panwar
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- 2022
60. Investigation on Thermodynamic Properties of Novel Ag2SrSn(S/Se)4 Quaternary Chalcogenide for Solar Cell Applications: A Density Functional Theory Study
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Ashutosh Srivastava, Trupti Ranjan Lenka, Jesuraj Anthoniappen, and S. K. Tripathy
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- 2022
61. Network approach to understand biological systems: From single to multilayer networks
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Sayantoni Chaudhuri and Ashutosh Srivastava
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Cell Communication ,General Medicine ,General Agricultural and Biological Sciences ,Models, Biological ,Metabolic Networks and Pathways ,General Biochemistry, Genetics and Molecular Biology - Abstract
Network theory has led to the abstraction of many real-world systems and enabled their modelling as simple networks comprising nodes and edges. In particular, in the field of biological sciences, network theory provides a robust framework to capture the complexity inherent to biological systems. Networks in biology have been modelled at different scales, starting from cells to population levels. These models have provided crucial insights into the evolution, mechanism, and functions of several biological systems. However, most natural and engineered systems are composed of multiple subsystems and layers of connectivity. A multilayer network paradigm has proven useful in understanding such systems. Here, we have briefly introduced the network formalism of modelling biological systems at various levels. This is followed by an introduction to multilayer networks. Multilayer networks have been utilized to model biological systems at multiple scales ranging from protein-protein interactions, transcription and metabolic networks, to ecological networks involving interactions between species. Recent advances in studying the structure and dynamics of such multilayer networks have enabled a better understanding of the complexity in these biological systems. Finally, we discuss the recent advances in studying the structure and dynamics of such multilayered networks followed by the challenges and future prospects.
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- 2022
62. Strong Anharmonicity‐Induced Low Thermal Conductivity and High n‐type Mobility in the Topological Insulator Bi 1.1 Sb 0.9 Te 2 S
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Riddhimoy Pathak, Prabir Dutta, Ashutosh Srivastava, Divya Rawat, Radha Krishna Gopal, Abhishek K. Singh, Ajay Soni, and Kanishka Biswas
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General Medicine ,General Chemistry ,Catalysis - Published
- 2022
63. New Greener and Sustainable Methodology for Direct Sequestering and Analysis of Uranium Using a Maline Supramolecular Scaffold and Mechanistic Understanding through Speciation and Interaction Studies
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Nimai Pathak, Arijit Sengupta, Neetika Rawat, Rama Mohana Rao Dumpala, Manjulata Sahu, Ashok Kumar Yadav, Pooja Sahu, S. k. Musharaf Ali, and Ashutosh Srivastava
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Interaction studies ,Scaffold ,chemistry ,Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,Genetic algorithm ,Supramolecular chemistry ,Environmental Chemistry ,chemistry.chemical_element ,Nanotechnology ,General Chemistry ,Uranium - Published
- 2021
64. An Exhaustive Comparative Study of Network Simulation Tool
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Mamoon Rashid, Achintya Singhal, K. Vengatesan, Sachin Kumar Gupta, Ashutosh Srivastava, and Abhishek Kumar
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Computational Mathematics ,Computer science ,General Materials Science ,General Chemistry ,Data mining ,Electrical and Electronic Engineering ,Condensed Matter Physics ,computer.software_genre ,computer ,Network simulation - Abstract
In ongoing situation framing communication network takes a lot of time and cost. So, actualizing a system isn’t simple. Test system assists with mimicking an ongoing domain. In this manner the moment and expenditure for the checking usefulness of a system have been condensed and it is easy to implements. Network simulator accelerates the research and development process. It includes a development environment to model a network type. The aspire of this dissertation is to explore the features of a variety of types of simulator-emulator and consider their disadvantages and advantages and deeply examine about NS-2 and QualNet simulation tool with two modeled cases. We endeavor a decent reference for those individuals who feel trouble to choose the system test systems in their examination.
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- 2021
65. First principles investigations for structural, electronic, optical and elastic properties of Ag2BeSn(S/Se)4 chalcogenide in kesterite and stannite phases with theoretical SLME calculations
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Ashutosh Srivastava, Arun Mannodi-Kanakkithodi, T.R. Lenka, G. Palai, and S.K. Tripathy
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Electrical and Electronic Engineering ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2023
66. Novel technique to detect network error or modification of votes during transmission in online voting system
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Lokendra Singh Umrao, Rajiv Kumar, Ashutosh Srivastava, Sachin Kumar Gupta, and Mamoon Rashid
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Novel technique ,Algebra and Number Theory ,Computer science ,Applied Mathematics ,media_common.quotation_subject ,010103 numerical & computational mathematics ,02 engineering and technology ,Online voting ,Computer security ,computer.software_genre ,01 natural sciences ,Network error ,Transmission (telecommunications) ,Voting ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,0101 mathematics ,computer ,Analysis ,Vulnerability (computing) ,media_common - Abstract
Major obstacles in deploying online voting system (OVS) are its susceptibility and vulnerability to attack and incompatibility to voting fundamental. Various security risks like attacks on communic...
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- 2021
67. Bio-efficacy of weed management practices in rainfed potato
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T.K. Bag, Ashutosh Srivastava, V.P. Yadav, and Sanjay Yadav
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business.industry ,Biology ,business ,Weed control ,Biotechnology ,Bio efficacy - Published
- 2021
68. Frequency Selective SIW Filter Design
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Rahul Tiwari, Ashutosh Srivastava, and Venkateswaran K
- Published
- 2022
69. Cultivation and Production Techniques of Marine Algae
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Subhasha Nigam, Ashutosh Srivastava, Arti Srivastava, and Surbhi Sinha
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Algae ,biology ,Botany ,Environmental science ,Production (economics) ,biology.organism_classification - Published
- 2020
70. A TWO-SCALE APPROACH FOR THE DROP SHOCK SIMULATION OF A PRINTED CIRCUIT BOARD PACKAGE CONSIDERING REFLOWED SOLDER BALL GEOMETRIES
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Wei Hu, Siddharth Shah, Cheng-Tang Wu, Ashutosh Srivastava, Dandan Lyu, and Xiaofei Pan
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Printed circuit board ,Materials science ,Computer Networks and Communications ,Control and Systems Engineering ,Drop (liquid) ,Computational Mechanics ,Mechanical engineering ,Particle method ,Navier stokes ,Solder ball ,Co-simulation - Published
- 2020
71. Smart Agriculture Using UAV and Deep Learning
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Krishna Keshob Paul, Jishnu Dev Roy, Sourav Sarkar, Sena Kumar Barai, Abu Sufian, Sachin Kumar Gupta, and Ashutosh Srivastava
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- 2022
72. Towards Acid Free Plutonium Recovery from Assorted Matrices: Non-Aqueous Leaching Followed by Selective Solid Phase Extraction
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Shiny S. Kumar, Ankita Rao, Ashutosh Srivastava, Kartikey K. Yadav, and R. K. Lenka
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
73. Generation of 3d Water Vapour Tomography Using Voxel Based Approach in the Himalayan Region
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Ashutosh Srivastava
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- 2022
74. Interfacial carbon fiber–matrix interactions in thermosetting composites volumetrically cured by electromagnetic fields
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Anubhav Sarmah, Madeline A. Morales, Ashutosh Srivastava, Shegufta Upama, Ankush Nandi, Todd C. Henry, Micah J. Green, and Aniruddh Vashisth
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Mechanics of Materials ,Ceramics and Composites - Published
- 2023
75. Automatic Shopping Cart System using ZigBee Technology and RFID Module
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Nakshatar Sharma, Akshita Gupta, Sachin Kumar Gupta, Radha Raman Chandan, Ashutosh Srivastava, and Poonam Yadav
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- 2021
76. Reliability Analysis of Flexible PCBs
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Amogh Shejwal, Ashutosh Srivastava, Sandeep Medikonda, and S. Babu Aminjikarai
- Abstract
Flexible Circuit Boards (FCB) are ubiquitous in most electronic devices used today. These are utilized in mobile phones, display cables in laptops, cameras, smart watches, robotic arms and more. They are mainly used in applications where space, flexibility and construction constraints limit the usage of conventional Printed Circuit Board (PCB). While FCBs offer numerous advantages over traditional PCBs, like enhanced reliability, capabilities, reduced weight, and lesser space utilization, on the other hand, they present different set of challenges like assembly, installation, and difficulty in repairing and reworking after installation. The flexes are generally bent at several points before conforming to the installed state which induces stresses before the actual operation or the working phase. These stresses are further magnified during the cyclic loading which can lead to breakage of these flexes. Due to intricacies involved in FCBs, numerical modeling of these components is challenging. In this work, a methodology is developed in Ansys Mechanical™ to model the installation and operating phase of the FCB. Stresses generated in both the phases are calculated and fatigue life is computed after the operational phase. Two different models are analyzed. The first model is a Rigid Flex PCB, where a FCB connects with the rigid PCBs. The second model is a standalone FCB cable. For both the models, shell elements are used to mesh the FCBs, which are typically thin structures and experience a large amount of rotation and bending loads. Trace mapping feature is used to accurately model the large number of intricate features such as copper traces, vias and other Electronic-CAD data. The trace mapping feature simplifies the model by modeling the geometry as dielectric layers and includes the effect of traces by mapping the metal fraction onto the dielectric layers. The loop forming capability of both the models is analyzed where they are subjected to a 180° bend. The fatigue induced due to this bending load is calculated for both the models. For the FCB cable case, the work is extended to study the stresses developed in the installation phase as it impacts the overall fatigue life of the FCB. Here the rigid surface bodies are used to push/deform the FCB cable to its final installation stage. Lastly, a detailed High-Performance Computing (HPC) scalability study is performed in-order to find the best balance between the number of cores and solution time.
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- 2021
77. Compression Molding of Reinforced Plastics Using the Element Free Galerkin (EFG) Method
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Sandeep Medikonda, Ashutosh Srivastava, Amogh Shejwal, and Rajesh Meena
- Abstract
Composite materials using long fiber-reinforced plastics have seen increased usage in recent times due to their lightweight and better energy absorption characteristics. Compression molding, a high-volume, high-pressure method suitable for molding complex, high-strength fiberglass reinforcement plastics has been widely accepted in the manufacturing industry as an efficient process to mass-produce complicated shapes in a short time. Hence, it is of paramount importance to make this manufacturing process cost-effective and environmentally sustainable. To accomplish this, it becomes very important to understand different behaviors such as the fiber orientation, deformation, axial forces acting on the fibers, stresses occurring in the matrix, punch reaction force, etc. and the use of simulation-led design can help accomplish this with a high degree of accuracy. Considering the extreme high-pressure conditions that the reinforced plastics are subjected to, traditional finite element (FEM) numerical approaches tend to fall short when it comes to compression molding primarily due to severe mesh distortion. In this context, the EFG method has been considered in the current work. EFG, like FEM, is a spatial discretization method however is based on a particle-based approach. The domain of interest is decomposed into material particles and the support domain uses polynom functions to approximate field variables similar to the shape functions used in FEM. Additionally, a background mesh is typically used to integrate the weak forms for the momentum balance. A combination of this theoretical background of EFG, which minimizes the inherent mesh distortion limitation encountered in FEM, coupled with the ability to handle reinforcements and an adaptive mesh refinement method makes this approach suitable for compression molding applications. In this work, an approach to simulate the blank compression with and without fiber reinforcements using the EFG method has been presented. A separate implicit analysis was also carried out to calculate the spring back state of the non-reinforced model to identify the locations of the residual stresses. A 5-layer fiber-reinforced model with an orientation of [0/-45/90/45/0] was embedded into the matrix and the effect of the coupling behaviors between fibers and the matrix on the end deformed shape has also been studied. Primarily, the effect of having no axial resistance for the slip of the fibers versus defining a user-defined slip criterion on the wrinkling behavior has been compared. The approach presented in this work has shown great promise in simulating the compression molding of long fiber reinforced plastics.
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- 2021
78. WHAT IF SPIDERS MADE METAMATERIAL WEBS USING MATERIALS WITH MECHANICAL SIZE-EFFECTS?
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Ashutosh Srivastava, Aniruddh Vashisth, Eric Robert Behling, Siddhant Kumar, and Raphaël N. Glaesener
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Spider ,Materials science ,Dependency (UML) ,Plane (geometry) ,visual_art ,visual_art.visual_art_medium ,Metamaterial ,Ceramic ,Composite material ,Material properties ,Intensity (heat transfer) ,Topology (chemistry) - Abstract
Spider’s webs are elegant examples of natural composites that can absorb outof- plane impact energy to capture prey. Different spiders have different methods and structure of webs, and these variations in topologies have a significant effect on the prey catching abilities of the web. Taking inspiration from the spiders, metamaterials that have architectured topology can be fabricated according to end applications such as energy absorbers or impact tolerant materials. In this investigation, we theoretically examined impact loading on various orb-spider webs modeled with metamaterial architecture using materials that show size-dependent behavior. Using the size-dependent properties of nano-reinforced polymer-derived ceramics (PDCs), various metamaterial topologies were evaluated for out-of-plane impact due using ANSYS Ls-Dyna. The material properties capture the size dependency of the ceramics where smaller elements have higher strength due to reduced flaw intensity; the mechanical strength of these elements does not follow the conventional Griffith Theory. In this study, spider web geometries fabricated with PDCs with varying size elements were examined.
- Published
- 2021
79. USING DATA SCIENCE TO EVALUATE NANO-REINFORCED EPOXY SURFACES
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Chowdhury Ashraf, Jonathan Theim, Aniruddh Yashisth, Todd C. Henry, Utkarsh Dubey, Charles E. Bakis, Daniel P. Cole, and Ashutosh Srivastava
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Fracture toughness ,Materials science ,visual_art ,Composite number ,visual_art.visual_art_medium ,Micromechanics ,Modulus ,Particle ,Fracture mechanics ,Epoxy ,Data science ,Elastic modulus - Abstract
Toughened composites reinforced with nanofillers show improved mechanical performance such as increased abrasion resistance, fracture toughness, and fracture energy. The degree of these improvements is influenced by the degree of dispersion of the nanofillers which can be analyzed using force microscopy (AFM), a technique that allows for mapping the local height and elastic modulus of a surface. However, current AFM apparatuses can only measure a narrow range of moduli according to the type of tip, which complicates the full-field measurement of moduli in nanocomposites with nanosilica (~72 GPa) embedded in epoxy (0.1 – 5 GPa). Moreover, height mapping can only visualize filler particles exposed at the surface. These limitations make it challenging to determine the 3D location of nanoparticles near the surface of a composite. To overcome these limitations of conventional AFM, we used a combination of data science, micromechanics, and experimental data from AFM to locate the centroidal position of nanosilica (NS) particles relative to the surrounding epoxy surface. Using finite element simulations, a theoretical dataset of modulus values as a function of particle position relative to the epoxy surface was created as a training set. Bayesian optimization determines the “best” particle position that results in minimum error between simulated and experimental modulus contours. The algorithm returns the 3D position of the fully or partially embedded NS particle relative to the epoxy surface. The algorithm has shown the ability to partially produce simulated modulus contours that resemble the experimental modulus contours.
- Published
- 2021
80. Virtual screening of phytochemicals from Indian medicinal plants against the endonuclease domain of SFTS virus L polymerase
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R. P. Vivek-Ananth, Ajaya Kumar Sahoo, Ashutosh Srivastava, and Areejit Samal
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General Chemical Engineering ,General Chemistry - Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) causes a highly infectious disease with reported mortality in the range 2.8% to 47%. The replication and transcription of the SFTSV genome is performed by L polymerase, which has both an RNA dependent RNA polymerase domain and an N-terminal endonuclease (endoN) domain. Due to its crucial role in the cap-snatching mechanism required for initiation of viral RNA transcription, the endoN domain is an ideal antiviral drug target. In this virtual screening study for the identification of potential inhibitors of the endoN domain of SFTSV L polymerase, we have used molecular docking and molecular dynamics (MD) simulation to explore the natural product space of 14 011 phytochemicals from Indian medicinal plants. After generating a heterogeneous ensemble of endoN domain structures reflecting conformational diversity of the corresponding active site using MD simulations, ensemble docking of the phytochemicals was performed against the endoN domain structures. Apart from the ligand binding energy from docking, our virtual screening workflow imposes additional filters such as drug-likeness, non-covalent interactions with key active site residues, toxicity and chemical similarity with other hits, to identify top 5 potential phytochemical inhibitors of endoN domain of SFTSV L polymerase. Further, the stability of the protein-ligand docked complexes for the top 5 potential inhibitors was analyzed using MD simulations. The potential phytochemical inhibitors, predicted in this study using contemporary computational methods, are expected to serve as lead molecules in future experimental studies towards development of antiviral drugs against SFTSV.
- Published
- 2021
81. Estimation of GPS-based atmospheric precipitable water vapour over Dehradun
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Ashutosh Srivastava
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Meteorology ,Precipitable water ,business.industry ,Gps data ,Global Positioning System ,Annual average ,General Earth and Planetary Sciences ,Environmental science ,business - Abstract
Precipitable water vapour (PWV) is estimated using GPS data collected from the continuous operating reference station (CORS) located in Dehradun city, a valley in northwestern Himalayan region. PWV is also estimated using two well-established IGS stations observations in India to validate the retrieval process and to investigate PWV variation over these locations. Meteorological observations, required for PWV estimation, are acquired from NCEP by vertical and horizontal interpolation of grid points data for a specific station. The validation and accuracy assessment of all obtained parameters are carried out at different levels. The annual average PWV over Hyderabad (HYDE), Bangalore (IISC), and Dehradun (DEHR) are estimated to be 35.96, 31.70 and 22.10 mm, respectively. The average PWV differences are estimated to be around 1–3 mm if the comparison is made among GMET, IGS and NCEP derived PWVs. Estimated PWV over Dehradun is also compared with reanalysis data from the MERRA and an average difference of about 4 mm is observed.
- Published
- 2021
82. Effect of silicon application with mycorrhizal inoculation on Brassica juncea cultivated under water stress
- Author
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Ashutosh Srivastava, Vijay Kumar Sharma, Prashant Kaushik, Mohamed A. El-Sheikh, Shaista Qadir, and Sheikh Mansoor
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Silicon ,Multidisciplinary ,Dehydration ,Mycorrhizae ,Antioxidants ,Mustard Plant - Abstract
Brassica juncea L. is a significant member of the Brassicaceae family, also known as Indian mustard. Water is a limiting factor in the successful production of this crop. Here, we tested the effect of water shortage in B. juncea plants supplemented with or without the application of silicon and arbuscular mycorrhizal fungi in total 8 different treatments compared under open filed conditions using a randomised complete block design (RCBD). The treatments under control conditions were control (C, T1); C+Silicon (Si, T2); C+My (Mycorrhiza; T3); and C+Si+My (T4). In contrast, treatments under stress conditions were S (Stress; T5); S+Si (T6); S+My (T7) and S+Si+My (T8), respectively. In total, we evaluated 16 traits, including plant response to stress by evaluating peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activity. The fresh weight (g) increased only 7.47 percent with mycorrhiza (C+My) and 22.39 percent with silicon (C+Si) but increased 291.08 percent with both mycorrhiza and silicon (C+Si+My). Using mycorrhiza (S+My) or silicon (S+Si) alone produced a significant increase of 53.16 percent and 55.84 percent in fresh weight, respectively, while using both mycorrhiza and silicon (S+Si+My) together produced a dramatic increase of 380.71 percent under stress conditions. Superoxidase dismutase concentration (Ug−1 FW) was found to be increased by 29.48 percent, 6.71 percent, and 22.63 percent after applying C+My, C+Si and C+Si+My, but treatment under stress revealed some contrasting trends, with an increase of 11.21 percent and 19.77 percent for S+My, S+Si+My, but a decrease of 13.15 percent for S+Si. Finally, in the presence of stress, carotenoid content (mg/g FW) increased by 58.06 percent, 54.83 percent, 183.87 percent with C+My, and 23.81 percent with S+My and S+Si+My, but decreased by 22.22 percent with S+Si. Silicon application proved to be more effective than AMF treatment with Rhizophagus irregularis, and the best results were obtained with the combination of Si and AMF. This work will help to suggest the measures to overcome the water stress in B. juncea.
- Published
- 2021
83. Structural differences in the FAD-binding pockets and lid loops of mammalian CRY1 and CRY2 for isoform-selective regulation
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Florence Tama, Simon Miller, Yoshiki Aikawa, Ashutosh Srivastava, Tsuyoshi Hirota, and Yoshiko Nagai
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Gene isoform ,endocrine system ,animal structures ,Circadian clock ,Molecular Dynamics Simulation ,Crystallography, X-Ray ,01 natural sciences ,Biochemistry ,Protein Structure, Secondary ,03 medical and health sciences ,chemistry.chemical_compound ,Molecular dynamics ,Cryptochrome ,circadian clock ,Animals ,Protein Isoforms ,Conformational isomerism ,030304 developmental biology ,X-ray crystallography ,Flavin adenine dinucleotide ,Mammals ,0303 health sciences ,Multidisciplinary ,Binding Sites ,010405 organic chemistry ,fungi ,Tryptophan ,Biological Sciences ,0104 chemical sciences ,cryptochromes ,Biophysics and Computational Biology ,chemistry ,FAD binding ,Mutation ,Physical Sciences ,Biophysics ,Flavin-Adenine Dinucleotide ,sense organs ,small-molecule modulators - Abstract
Significance CRY1 and CRY2 regulate circadian rhythms, and their dysfunction has been associated with many diseases. Since they have not only similar but also independent functions, understanding of intrinsic differences between these highly similar proteins is required. Here, we determined CRY1 and CRY2 static and dynamic structures that exhibited conformational isomerism in their ligand-binding FAD pockets and neighboring lid loops, allowing mechanistic insight into structural features specific to each isoform. Structure-guided mutations supported important roles of interactions between a key “gatekeeper” tryptophan residue in the FAD pocket and lid loop residues in determining the effects of isoform-selective compounds. Our results provide insight into how near-identical ligand-binding pockets can intrinsically regulate compound selectivity through unique interactions with neighboring structural elements., The circadian clock is a biological timekeeper that operates through transcription–translation feedback loops in mammals. Cryptochrome 1 (CRY1) and Cryptochrome 2 (CRY2) are highly conserved core clock components having redundant and distinct functions. We recently identified the CRY1- and CRY2-selective compounds KL101 and TH301, respectively, which provide useful tools for the exploration of isoform-selective CRY regulation. However, intrinsic differences in the compound-binding FAD (flavin adenine dinucleotide) pockets between CRY1 and CRY2 are not well understood, partly because of nonoptimal properties of previously reported apo form structures in this particular region constituted by almost identical sequences. Here, we show unliganded CRY1 and CRY2 crystal structures with well-defined electron densities that are largely free of crystal contacts at the FAD pocket and nearby lid loop. We revealed conformational isomerism in key residues. In particular, CRY1 W399 and corresponding CRY2 W417 in the FAD pocket had distinct conformations (“out” for CRY1 and “in” for CRY2) by interacting with the lid loop residues CRY1 Q407 and CRY2 F424, respectively, resulting in different overall lid loop structures. Molecular dynamics simulations supported that these conformations were energetically favorable to each isoform. Isoform-selective compounds KL101 and TH301 preferred intrinsic “out” and “in” conformations of the tryptophan residue in CRY1 and CRY2, respectively, while the nonselective compound KL001 fit to both conformations. Mutations of lid loop residues designed to perturb their isoform-specific interaction with the tryptophan resulted in reversed responses of CRY1 and CRY2 to KL101 and TH301. We propose that these intrinsic structural differences of CRY1 and CRY2 can be targeted for isoform-selective regulation.
- Published
- 2021
84. Design and Implementation of Quadrifilar Helical Antenna for 60 GHz Band Application
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Ashutosh Srivastava
- Subjects
Physics ,HFSS ,Acoustics ,Extremely high frequency ,Return loss ,Helical antenna ,Antenna (radio) ,Electrical impedance ,Directivity ,Radiation pattern - Abstract
In this paper an extremely compact 4-wired Quadrifilar Helix Antenna (QHA) designed and simulated. The proposed Quadrifilar Helix antenna is exhibiting narrow-band radiation pattern around 60GHz frequency spectrum. The antenna has gain of 9-dBi at center operating frequency. The frequency of operation is 60 GHz. The simulated narrow band impedance bandwidth of the design is 2.1% with acceptable return loss (−10dB). Antenna is functioning in axial mode having axial ratio less than 1.1 for complete band of design operation. The consequences of design variation on the input reflection coefficient, radiation pattern with directivity and maximum gain of the QHA are investigated and the outcomes are examined for working frequency of the 60 GHz. The compete design simulation is executed through design and simulation tool Ansys high-frequency structure simulator (HFSS). The proposed antenna must be designed carefully because of its small dimensions. But it can be easily installed in any hand-held low power 5G enable devices. The offered antenna is aimed to work at millimeter wave region for added capability in the 60-GHz band (conventionally known for the WiGig) and also to stablish active system support for current and upcoming 5G networks.
- Published
- 2021
85. Low-Profile Broadband MIMO Antenna for 5G Mobile Communication
- Author
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K. Venkateswaran and Ashutosh Srivastava
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Physics ,Waveguide (electromagnetism) ,HFSS ,Acoustics ,MIMO ,Slot antenna ,Antenna (radio) ,Reflection coefficient ,Antenna gain ,Coaxial - Abstract
In this paper, a $2\times 2$ square and close-packed four Substrate Integrated Waveguide (SIW) slot-element multiple-I/P and multiple-O/P (MIMO) antenna is designed and simulated. The proposed design is built on the extremely promising SIW technology. The basic single element of the complete design is an SIW cavity slot antenna. Each element of four element MIMO antenna is placed in a 90° shifted orientation. So that, the four rectangle cavities having unblocked boundaries are designed. These elements are structured next to each other without sharing any row of metallic posts. Then, a radiating rectangular slot is made on each element that has been placed on top layer. All these four slots are excited by using coaxial input ports. The four antenna elements with close-packed dimensions are created and these antennas will emit electromagnetic wave via cavity side edges and etched slots. To improve the antenna isolation, slot length and width may be adjusted through these interconnected elements. The proposed $2\times 2$ element MIMO antenna system shows the ansys HFSS, which has simulated radiation behavior from 27.6 GHz to 34.8 GHz with an input reflection coefficient (S 11 ) less than −10dB. The port input reflation coefficient (S 11 ) is as minimum as −30dB by having peak antenna gain of 4.9 dBi with an efficiency of 90.4%. The small and efficient size along with effective isolation design creates the planned smart design for real-world applications.
- Published
- 2021
86. A novel pilot study on imaging‐based identification of fish exposed to heavy metal (Hg) contamination
- Author
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Ashutosh Srivastava, Hardik Gupta, Arti Srivastava, Malay Kishore Dutta, Anushikha Singh, and Rakesh Chandra Joshi
- Subjects
General Chemical Engineering ,Environmental chemistry ,%22">Fish ,Environmental science ,Identification (biology) ,General Chemistry ,Contamination ,Food Science - Published
- 2021
87. A controlled, reproducible, and extensible experiment for evaluating the impact of Tor latency
- Author
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Shivendra S. Panwar, Fraida Fund, Bintia Keita, and Ashutosh Srivastava
- Subjects
Measure (data warehouse) ,Computer science ,business.industry ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Cloud computing ,Usability ,Extensibility ,Web page ,ComputingMilieux_COMPUTERSANDSOCIETY ,The Internet ,Latency (engineering) ,business ,Anonymity ,Computer network - Abstract
The Tor anonymity network is an essential protection for those living in oppressive regimes, who may be persecuted for their speech or other activities on the Internet. However, its usability is severely affected by high latency. Furthermore, because of the difficulty associated with conducting research evaluations on the Tor network, there has been insufficient research aimed at this problem. To address this, we develop a CloudLab profile that instantiates a private Tor testing network for easy, reproducible experimental evaluations on Tor. We demonstrate how to use this CloudLab profile to measure the page load time of selected web pages over a Tor network under different network conditions representative of typical Tor usage.
- Published
- 2021
88. Approaches in development of DNA based identification system for industrially important timber species
- Author
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Vageeshbabu S. Hanur, M. Srinivasa Rao, Tanzeem Fatima, and Ashutosh Srivastava
- Subjects
chemistry.chemical_compound ,chemistry ,Computer science ,Biochemical engineering ,DNA ,Identification system - Published
- 2019
89. Harmonics generated by Electric Arc Furnace in Electric Power System - A Review
- Author
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Ashutosh Srivastava and Amarjeet Singh
- Subjects
Materials science ,business.industry ,Electrical engineering ,General Medicine ,Power factor ,law.invention ,Electric power system ,law ,Power electronics ,Harmonics ,Electrical network ,Electric power ,business ,Electric arc furnace ,Voltage - Abstract
An electrical power system is designed to operate at the frequency of 50 Hz or 60 Hz. But there are certain loads which generate voltage and current that are the integer multiple of 50 or 60 Hz. Those higher frequencies form electrical network pollution called as power system harmonics. An Electric Arc Furnace (EAF) is one of such load when operated on AC affects the power quality of the power system. The power quality is degraded mainly due to the poor power factor, current and voltage harmonics and voltage fluctuation. The problems due the harmonics is getting worsen day by day due to the introduction of power electronics equipments and voltage fluctuation arise by the use of large industrial load such as EAFs and LMF (Ladle Melt Furnace) in steel meting shop. Also connecting rolling mill and forging shop generate harmonics in the adjacent electrical power system. In this paper, an extensive review of harmonics generated in EAF is presented .
- Published
- 2019
90. Bipartite anchoring of SCREAM enforces stomatal initiation by coupling MAP kinases to SPEECHLESS
- Author
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Keiko U. Torii, Florence Tama, Ashutosh Srivastava, Jian-Kang Zhu, Aarthi Putarjunan, Ning Zheng, Alex K. Hofstetter, Chunzhao Zhao, Amanda L. Rychel, Jim Ruble, and Xiaobo Tang
- Subjects
0106 biological sciences ,0301 basic medicine ,Amino Acid Motifs ,Arabidopsis ,Plant Science ,Plasma protein binding ,Biology ,Cell fate determination ,01 natural sciences ,Article ,03 medical and health sciences ,Downregulation and upregulation ,Gene Expression Regulation, Plant ,Atomic resolution ,Basic Helix-Loop-Helix Transcription Factors ,Transcription factor ,030304 developmental biology ,Mitogen-Activated Protein Kinase Kinases ,Regulation of gene expression ,0303 health sciences ,Arabidopsis Proteins ,Kinase ,biology.organism_classification ,Cell biology ,030104 developmental biology ,Plant Stomata ,Phosphorylation ,Mitogen-Activated Protein Kinases ,Signal transduction ,Reprogramming ,Protein Binding ,Signal Transduction ,010606 plant biology & botany - Abstract
Cell fate in eukaryotes is controlled by mitogen-activated protein kinases (MAPKs) that translate external cues into cellular responses. In plants, two MAPKs—MPK3 and MPK6—regulate diverse processes of development, environmental response and immunity. However, the mechanism that bridges these shared signalling components with a specific target remains unresolved. Focusing on the development of stomata—epidermal valves that are essential for gas exchange and transpiration—here, we report that the basic helix-loop-helix protein SCREAM functions as a scaffold that recruits MPK3/6 to downregulate SPEECHLESS, a transcription factor that initiates stomatal cell lineages. SCREAM directly binds to MPK3/6 through an evolutionarily conserved, yet unconventional, bipartite motif. Mutations in this motif abrogate association, phosphorylation and degradation of SCREAM, unmask hidden non-redundancies between MPK3 and MPK6, and result in uncontrolled stomatal differentiation. Structural analyses of MPK6 with a resolution of 2.75 A showed bipartite binding of SCREAM to MPK6 that is distinct from an upstream MAPKK. Our findings elucidate, at the atomic resolution, the mechanism that directly links extrinsic signals to transcriptional reprogramming during the establishment of stomatal cell fate, and highlight a unique substrate-binding mode adopted by plant MAPKs. Arabidopsis MPK3 and MPK6 are involved in many biological processes. How do they achieve their signalling specificity? Structural, biochemical and genetic approaches show that the bHLH protein SCREAM acts as a scaffold to recruit downstream substrates during stomatal development.
- Published
- 2019
91. Asynchronous flowering in clonal seed orchards - An effective strategy for alternative management
- Author
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H.C. Yashavantha Rao, Ashutosh Srivastava, Soma Mondal, and Geeta Joshi
- Subjects
Agronomy ,Asynchronous communication ,Biology - Published
- 2019
92. Genetic Diversity Estimates of Santalum album L. through Microsatellite Markers: Implications on Conservation
- Author
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P. V. Somashekar, Vageeshbabu S. Hanur, Ashutosh Srivastava, Tanzeem Fatima, and M. Srinivasa Rao
- Subjects
0106 biological sciences ,Sandalwood ,Genetic diversity ,Veterinary medicine ,education.field_of_study ,biology ,Population ,Santalum ,04 agricultural and veterinary sciences ,General Medicine ,biology.organism_classification ,01 natural sciences ,Osyris lanceolata ,Genetic variation ,Genetic structure ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,education ,Santalum album ,010606 plant biology & botany - Abstract
Sandalwood (Santalum album L.) is the second most expensive wood in the world. There are approximately 16 species of sandalwood (S. album, S. spicatum, S. austrocaledonicum, S. yasi, S. lanceolatum, S. ellipticum, S. macgregorii, S. insulare) occurring naturally throughout Australia, India, Indonesia, Papua New Guinea and the islands of the South Pacific. In India, S. album is found all over the country, with over 90% of the area in Karnataka, Tamil Nadu, Kerala, Andhra Pradesh and Telangana state. It is highly economic tropical tree species because of its scented heartwood and heartwood oil. Several causes have been attributed to the depletion of sandalwood population mainly amongst which theft is causing negative effect on the quality of species by constant removal of superior clones. The aim of this study was to determine the genetic diversity of S. album. For this, 177 genotypes of S. album from 14 populations of three states (Karnataka, Telangana state and Kerala) in southern India were selected. The genetic diversity and genetic structure were characterized through 25 SSR markers developed by cross amplification of different species of Sandalwood. Under this study, following genetic diversity parameters were estimated at individual level and population level; Number of alleles (Na) 9.107, Effective number of alleles (Ne) 7.56, Observed heterozygosity (Ho) 0.187, Expected heterozygosity (He) 0.861, Shannon information index (I) 2.03, F statistics 0.89, Polymorphic information content (PIC) 0.87 and Gene flow (Nm) 4.98. The estimates of gene flow among the populations of Kodada Telangana (Nm = 15.109); IWST Karnataka (Nm = 13.62) than across other geographical populations (Nm = 9.40). Analysis of molecular variance (AMOVA) revealed that 3% of the total variation was due to differences among populations and 97% due to differences within the populations. The genetic differentiation among populations (FST) 0.012 at p results showed the combined variation 82.2% of these markers. This study highlights the knowledge of genetic variation in sandalwood across the herd population of sandalwood in India. The highest range of polymorphism was detected with SSR markers developed from Osyris lanceolata compared to Santalum. austrocaledonicum, Santalum. insulare and Santalum. spicatum. This study would help in conservation of the Sandalwood populations with high profile of genetic diversity and selection of clones for genetic improvement program.
- Published
- 2019
93. Decoupled atomic contribution boosted high thermoelectric performance in mixed cation spinel oxides ACo2O4
- Author
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Madhubanti Mukherjee, Ashutosh Srivastava, and Abhishek Singh
- Subjects
Physics and Astronomy (miscellaneous) - Abstract
Decoupling the interdependence of various transport parameters in materials has been an intractable challenge in designing efficient thermoelectric materials. Using the first-principles density functional theory and the semi-classical Boltzmann transport theory, we demonstrate that the crucial criteria of obtaining suitable electronic and thermal transport have been achieved by utilizing the presence of mixed cations in spinel oxides. Differently coordinated cations present in spinel oxides lead to decoupled cationic contribution to the electronic and thermal transport properties. While electronic transport properties are controlled by tetrahedrally coordinated cation B (Co), the octahedrally coordinated cations A (Zn/Cd) only contribute to the thermal transport of the system. The combination of heavy bands in the electronic dispersions and tetrahedrally coordinated environment of Co results into an enhanced power factor. Additionally, the substitution of Cd leads to one order of magnitude reduction in the lattice thermal conductivity ( κl) without affecting the electronic transport properties. The significant reduction in κl has been attributed to the large mass difference, and remarkably strong anharmonic phonon scattering introduced by Cd. Simultaneously achieved high power factor and low lattice thermal conductivity result in a maximum figure of merit of 1.68 in CdCo2O4 spinel oxide. The approach of decoupling atomic contributions utilizing various cationic sites demonstrates a potential route to enhance thermoelectric performance.
- Published
- 2022
94. Side-by-side comparison of pre- and post-transferred LEDs grown on 2D hexagonal boron nitride onto arbitrary substrates
- Author
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Soufiane Karrakchou, Ashutosh Srivastava, Paul L. Voss, Abdallah Ougazzaden, Suresh Sundaram, Phuong Vuong, Adama Mballo, Ali Ahaitouf, Rajat Gujrati, Jean-Paul Salvestrini, Taha Ayari, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), ANR INMOST, and ANR-19-CE08-0025,INMoSt,Cellules solaires multi-jonctions multi-fils à base de nano-pyramides d'InGaN(2019)
- Subjects
Materials science ,Fabrication ,Hexagonal boron nitride ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,[SPI]Engineering Sciences [physics] ,law ,0103 physical sciences ,Pre and post ,Boron ,3D metrology ,business.industry ,Adhesion ,Measurement devices ,021001 nanoscience & nanotechnology ,Light emitting diodes ,Sapphire ,Heterojunctions ,Optoelectronics ,Materials processing ,0210 nano-technology ,business ,Material characterization ,Layer (electronics) ,Light-emitting diode - Abstract
International audience; We present a critical study of LEDs on h-BN compared to the conventional LEDs on sapphire from materials characterizations, device fabrication to the device performances measurements performed before and after liftoff and transfer with and without intermediary adhesion layer to arbitrary substrates.
- Published
- 2021
95. Van der Waals epitaxy of nitride optoelectronic devices based on two-dimensional hBN
- Author
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Paul L. Voss, Abdallah Ougazzaden, Simon Gautier, Tarik Moudakir, Ali Ahaitouf, Gilles Patriarche, Phuong Vuong, Jean-Paul Salvestrini, Adama Mballo, Ashutosh Srivastava, Suresh Sundaram, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), ANR Labex Ganex, ANR-11-LABX-0014,GANEX,Réseau national sur GaN(2011), and ANR-10-EQPX-0050,TEMPOS,Microscopie electronique en transmission sur le plateau Palaiseau Orsay Saclay(2010)
- Subjects
Materials science ,Photodetector ,02 engineering and technology ,Substrate (electronics) ,Nitride ,Field effect transistors ,Optoelectronic devices ,01 natural sciences ,law.invention ,010309 optics ,chemistry.chemical_compound ,[SPI]Engineering Sciences [physics] ,law ,0103 physical sciences ,Metalorganic vapour phase epitaxy ,business.industry ,Sensors ,Photodetectors ,Heterojunction ,021001 nanoscience & nanotechnology ,Light emitting diodes ,chemistry ,Boron nitride ,Heterojunctions ,Optoelectronics ,Photonics ,0210 nano-technology ,business ,Light-emitting diode ,Epitaxy - Abstract
International audience; Combined photonic and electronic systems require diverse devices to be co-integrated on a common platform. This heterogeneous integration is made possible through several separation and transfer methods where the functioning epilayers are essentially released from their growth substrate. The use of 2D layered h-BN as a mechanical release layer has been demonstrated to be a promising technique for the hybrid integration of III-nitride devices. In this talk we will give an overview of our results on wafer-scale van der Waals epitaxy by MOVPE of different III-N heterostructure devices such as LEDs, HEMTs, solar cells, sensors and photodetectors. Furthermore, mechanical release and transfer techniques of crack-free III-N devices on foreign substrates will be presented along with a comparison between the device performances before and after transfer.
- Published
- 2021
96. Photopharmacological Manipulation of Mammalian CRY1 for Regulation of the Circadian Clock
- Author
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Simon Miller, Tsuyoshi Oshima, Ayato Sato, Florence Tama, Akiko Sugiyama, Ashutosh Srivastava, Yoshiko Nagai, Kazuma Amaike, Ben L. Feringa, Yugo Aoki, Wiktor Szymanski, Tsuyoshi Hirota, Piermichele Kobauri, Kenichiro Itami, Dušan Kolarski, Synthetic Organic Chemistry, and Basic and Translational Research and Imaging Methodology Development in Groningen (BRIDGE)
- Subjects
endocrine system ,animal structures ,Light ,Period (gene) ,Circadian clock ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,Article ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Circadian Clocks ,Benzophenone ,Moiety ,Sleep phase ,Animals ,Humans ,Circadian rhythm ,Photolyase ,Chemistry ,fungi ,General Chemistry ,0104 chemical sciences ,Chemical screening ,Cryptochromes ,Biophysics ,sense organs - Abstract
CRY1 and CRY2 proteins are highly conserved components of the circadian clock that controls daily physiological rhythms. Disruption of CRY functions are related to many diseases, including circadian sleep phase disorder. Development of isoform-selective and spatiotemporally controllable tools will facilitate the understanding of shared and distinct functions of CRY1 and CRY2. Here, we developed CRY1-selective compounds that enable light-dependent manipulation of the circadian clock. From phenotypic chemical screening in human cells, we identified benzophenone derivatives that lengthened the circadian period. These compounds selectively interacted with the CRY1 photolyase homology region, resulting in activation of CRY1 but not CRY2. The benzophenone moiety rearranged a CRY1 region called the "lid loop"located outside of the compound-binding pocket and formed a unique interaction with Phe409 in the lid loop. Manipulation of this key interaction was achieved by rationally designed replacement of the benzophenone with a switchable azobenzene moiety whose cis-trans isomerization can be controlled by light. The metastable cis form exhibited sufficiently high half-life in aqueous solutions and structurally mimicked the benzophenone unit, enabling reversible period regulation over days by cellular irradiation with visible light. This study revealed an unprecedented role of the lid loop in CRY-compound interaction and paves the way for spatiotemporal regulation of CRY1 activity by photopharmacology for molecular understanding of CRY1-dependent functions in health and disease.
- Published
- 2021
97. Real-Time Data Pipeline in Confluent Kafka and Mule4 ESB with ActiveMQ
- Author
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Prashant Johri, Nitin K Gaur, Ashutosh Srivastava, Arvind Kumar, and Rachna Jain
- Subjects
Data flow diagram ,Computer science ,Reliability (computer networking) ,Distributed computing ,Scalability ,Data analysis ,Use case ,Real-time data ,Throughput (business) ,Pipeline (software) - Abstract
Integrating system has been a one handful of task and with the growth of technologies, and the data being generated in large amount has been one of the difficult tasks to ensure the reliable and secure transfer of data or messages with 100% accuracy. This is where the question arises which ESB tool is best in this scenario and performance parameters like message throughput, reliability, stability and hardware utilization. Data is modern days’ currency, and with the speed of data expanding exponentially, its storage and processing have also become a vital aspect. The data has been the inspiration of Internet systems in the application fields of advertisement, relevant searching, recommender systems and security, furthermore playing its part in areas of data analytics and logs reporting. Pub-sub as well as event-driven streaming is a distributed interaction paradigm well adapted to the deployment of scalable and loosely coupled systems. There are various use cases that require real-time data feeds for better results. The use of integrated systems such as Mule4 ESB with ActiveMQ JMS and Confluent Kafka analyzes the real-time data flow in various scenarios and coming up with a suitable system that has enhanced performance. In this paper, we will discuss a few of the common use cases based on the parameters such as performance and throughput and a qualitative and quantitative comparison of the two integration paradigms as to which of them are suitably sufficient to support large-scale systems with their message throughput capabilities.
- Published
- 2021
98. Role of Arsenic in Carcinogenesis
- Author
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Stephen James, Saniya Arfin, Manish K. Mishra, Arun Kumar, Niraj Kumar Jha, Saurabh Kumar Jha, Kavindra Kumar Kesari, Prabhanshu Kumar, Ashutosh Srivastava, and Dhruv Kumar
- Published
- 2021
99. Towards P-Type Conduction in Hexagonal Boron Nitride: Doping Study and Electrical Measurements Analysis of hBN/AlGaN Heterojunctions
- Author
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Soufiane Karrakchou, Adama Mballo, Jean-Paul Salvestrini, Yacine Halfaya, Suresh Sundaram, Paul L. Voss, Abdallah Ougazzaden, Phuong Vuong, Ashutosh Srivastava, Simon Gautier, Ali Ahaitouf, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Institut Lafayette, ANR Labex Ganex, and ANR-11-LABX-0014,GANEX,Réseau national sur GaN(2011)
- Subjects
Materials science ,heterojunction ,Band gap ,General Chemical Engineering ,Analytical chemistry ,02 engineering and technology ,doping ,magnesium ,01 natural sciences ,Article ,law.invention ,lcsh:Chemistry ,[SPI]Engineering Sciences [physics] ,wide bandgap ,law ,0103 physical sciences ,General Materials Science ,Electrical measurements ,h-BN ,Diode ,010302 applied physics ,Photocurrent ,Doping ,Heterojunction ,021001 nanoscience & nanotechnology ,Secondary ion mass spectrometry ,lcsh:QD1-999 ,0210 nano-technology ,Light-emitting diode - Abstract
Reliable p-doped hexagonal boron nitride (h-BN) could enable wide bandgap optoelectronic devices such as deep ultra-violet light emitting diodes (UV LEDs), solar blind photodiodes and neutron detectors. We report the study of Mg in h-BN layers as well as Mg h-BN/AlGaN heterostructures. Mg incorporation in h-BN was studied under different biscyclopentadienyl-magnesium (Cp2Mg) molar flow rates. 2&theta, &omega, x-ray diffraction scans clearly evidence a single peak, corresponding to the (002) reflection plane of h-BN with a full-width half maximum increasing with Mg incorporation in h-BN. For a large range of Cp2Mg molar flow rates, the surface of Mg doped h-BN layers exhibited characteristic pleats, confirming that Mg doped h-BN remains layered. Secondary ion mass spectrometry analysis showed Mg incorporation, up to 4 ×, 1018 /cm3 in h-BN. Electrical conductivity of Mg h-BN increased with increased Mg-doping. Heterostructures of Mg h-BN grown on n-type Al rich AlGaN (58% Al content) were made with the intent of forming a p-n heterojunction. The I-V characteristics revealed rectifying behavior for temperatures from 123 to 423 K. Under ultraviolet illumination, photocurrent was generated, as is typical for p-n diodes. C-V measurements evidence a built-in potential of 3.89 V. These encouraging results can indicate p-type behavior, opening a pathway for a new class of wide bandgap p-type layers.
- Published
- 2021
100. Effectiveness of selective area growth using van der Waals h-BN layer for crack-free transfer of large-size III-N devices onto arbitrary substrates
- Author
-
Simon Gautier, Soufiane Karrakchou, Ali Ahaitouf, Phuong Vuong, Tarik Moudakir, Gilles Patriarche, Rajat Gujrati, Ashutosh Srivastava, Suresh Sundaram, Thierry Leichle, Taha Ayari, Adama Mballo, Jean-Paul Salvestrini, Paul L. Voss, Abdallah Ougazzaden, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Équipe Microsystèmes électromécaniques (LAAS-MEMS), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, ANR Labex Ganex, ANR Inmost (AAP 2019), ANR-19-CE08-0025,INMoSt,Cellules solaires multi-jonctions multi-fils à base de nano-pyramides d'InGaN(2019), ANR-11-LABX-0014,GANEX,Réseau national sur GaN(2011), Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), and Université de Toulouse (UT)
- Subjects
Materials science ,Silicon ,Science ,chemistry.chemical_element ,02 engineering and technology ,Dielectric ,Epitaxy ,Two-dimensional materials ,01 natural sciences ,Article ,law.invention ,symbols.namesake ,[SPI]Engineering Sciences [physics] ,law ,0103 physical sciences ,Electronic devices ,010302 applied physics ,Multidisciplinary ,business.industry ,021001 nanoscience & nanotechnology ,chemistry ,Sapphire ,symbols ,Medicine ,Optoelectronics ,Photonics ,van der Waals force ,0210 nano-technology ,business ,Layer (electronics) ,Light-emitting diode - Abstract
Selective Area van der Waals Epitaxy (SAVWE) of III-Nitride device has been proposed recently by our group as an enabling solution for h-BN-based device transfer. By using a patterned dielectric mask with openings slightly larger than device sizes, pick-and-place of discrete LEDs onto flexible substrates was achieved. A more detailed study is needed to understand the effect of this selective area growth on material quality, device performance and device transfer. Here we present a study performed on two types of LEDs (those grown on h-BN on patterned and unpatterned sapphire) from the epitaxial growth to device performance and thermal dissipation measurements before and after transfer. Millimeter-size LEDs were transferred to aluminum tape and to silicon substrates by van der Waals liquid capillary bonding. It is shown that patterned samples lead to a better material quality as well as improved electrical and optical device performances. In addition, patterned structures allowed for a much better transfer yield to silicon substrates than unpatterned structures. We demonstrate that SAVWE, combined with either transfer processes to soft or rigid substrates, offers an efficient, robust and low-cost heterogenous integration capability of large-size devices to silicon for photonic and electronic applications.
- Published
- 2020
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