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A high aspect ratio surface micromachined accelerometer based on a SiC-CNT composite material

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microsystems & Nanoengineering 2024年第2期10卷 219-230页

作者： Jiarui mo shreyas Shankar Roberto Pezone Guoqi Zhang Sten Vollebregt Laboratory of Electronic Components Technology and Materials(ECTM)Department of MicroelectronicsDelft University of TechnologyDelftThe Netherlands

Silicon carbide(SiC)is recognized as an excellent material for microelectromechanical systems(mEmS),especially those operating in challenging environments,such as high temperature,high radiation,and corrosive environments.However,SiC bulk micromachining is still a challenge,which hinders the development of complex SiC mEmS.To address this problem,we present the use of a carbon nanotube(CNT)array coated with amorphous SiC(a-SiC)as an alternative composite material to enable high aspect ratio(HAR)surface micromachining.By using a prepatterned catalyst layer,a HAR CNT array can be grown as a structural template and then densified by uniformly filling the CNT bundle with LPCVD a-SiC.The electrical properties of the resulting SiC-CNT composite were characterized,and the results indicated that the electrical resistivity was dominated by the CNTs.To demonstrate the use of this composite in mEmS applications,a capacitive accelerometer was designed,fabricated,and measured.The fabrication results showed that the composite is fully compatible with the manufacturing of surface micromachining devices.The Young’s modulus of the composite was extracted from the measured spring constant,and the results show a great improvement in the mechanical properties of the CNTs after coating with a-SiC.The accelerometer was electrically characterized,and its functionality was confirmed using a mechanical shaker.

关键词： composite surface electrical

Nitrogen Dioxide, Carbon monoxide, Natural and Anthropomorphic Effects, and Earth’s Changing Climate

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Atmospheric and Climate Sciences 2023年第1期13卷 62-71页

作者： shreyas Banaji Flint Hill School NASA/Virginia Earth System Science Scholars Oakton USA

This study will both compare and contrast the characteristics and roles of two pollutants: nitrogen dioxide and carbon monoxide. It will begin by tracing each gas’ negative contributions to the Earth’s spheres, as well as relate any negative links that each plays concerning human activity, health, and interaction with the environment. It will include an in-depth analysis of what the proliferation of such toxic gases indicates about human production and causality, plus reflect on any current attempts being made to improve the effects of these pollutants on the environment. This examination will also inspect three NASA missions, i.e., mOPITT/Terra, AIRS/Aqua, and OmI/Aura, the aim of which, among many other tasks, is to detect pollutants within the Earth’s various spheres, as well as analyze weather anomalies, improve prediction methodology, and chronicle meteorological patterns for future study. It will also cover some of the goals, engineering breakthroughs, and in one case, the limitations, of these three satellite missions. Finally, it should be noted that in all stages of this discussion, the author’s main aim will be to focus on the positives that need to be implemented in order to improve the current situations that both anthropogenic and natural disasters have created for the planet.

关键词： Carbon monoxide Nitrogen Dioxide Climate Change Atmosphere Greenhouse Gases

Colony Collapse Disorder, Neonicotinoids, CO₂, Climate Change, and the Four Spheres

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Open Journal of Ecology 2022年第11期12卷 711-717页

作者： shreyas Banaji Flint Hill School/NASA VESSS Oakton VA USA

This analysis focuses on what effects the decline of both domestic and wild bee populations has on the environment. It will analyze the 21st century-coined phenomenon known as “Colony Collapse Disorder,” and will investigate research methods that have improved numbers within bee populations over the last two decades. Within this study, the impacts and interactions between the Colony Collapse Disorder phenomenon and various environmental factors will be discussed, as well as the interactions between the four main spheres of the Earth (i.e., the biosphere, lithosphere, atmosphere, and hydrosphere). In so doing, this study will evidence how and why bee populations are declining, why that decline affects each Earth sphere, as well as how this condition could create both loophole and contagion effects. Finally, this analysis will also briefly touch upon NASA’s increasing involvement with replenishing the world’s bee populations, the agency’s monitoring of CO2 levels, various ecosystems, and other such relevant and ongoing research.

关键词： Bees Extinction Pollination Pesticides Climate Change Agriculture Colony Collapse Disorder

Geological Specimens, minerals, and Actions Affecting Polar Shift and Earth’s magnetic Field

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International Journal of Geosciences 2022年第10期13卷 875-881页

作者： shreyas Banaji Flint Hill School NASA/VESS Program Oakton VA USA

This study will touch upon Earth’s magnetic field, the four spheres, and their relationship with polar shift influenced by the magnetization of the interior and surface areas. It will outline how certain aspects within the spheres are influenced by magnetization of minerals and localized rock, how such can be contained deep within Earth’s mantle areas, as well as how mining deposits of iron ore can affect other spheres and systems. It will also entail a brief explanation of geological research concerning the Pacific Ocean floor, as well as a discussion on the magnetization of minerals retaining their properties at extremely high temperatures within Earth’s interior. There will be explanations of how various spheres interact with each other, but it should be noted that while some findings here might seem unsubstantiated, any analysis of Earth’s interior and exterior, the magnetic field, polar shift, and its contagion effect upon living organisms, is still, somewhat, in its initial research stages, and is, at times, left to hypotheses concerning anomalous indications. This study is not conclusive. It has, at best, pieced together areas of relevance. Concluded here is that each event affects polar shift. How this has been affected by magnetization is not completely, at this time, understood. Furthermore, this report in no way promotes the “doomsday scenario”, prolific, fairly recently, within some of the scientific literature on this subject, particularly in Europe. This paper closely adheres to the most modern theories, and will try, at best, to leave speculation to science fiction writers.

关键词： Polar Shift magnetic Field Atmosphere Lithosphere Hydrosphere Biosphere Iron Ore Hematite magnetite

Security model for Cloud Computing: Case Report of Organizational Vulnerability

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信息安全(英文) 2023年第4期14卷 250-263页

作者： Sakharkar shreyas Independent Author Stevenson Ranch CA USA

Cloud computing services have quickly become a mainstay in business, leading to success as a business model and numerous advantages from the client’s point of view. Ease and amount of storage and computational services provisions were not previously accessible or affordable. However, parallel to this explosion has been significant security risk concerns. Thus, it is important to understand and define these security risks in a cybersecurity framework. This paper will take a case study approach to approach past security risks and propose a model that can be followed by organizations to eliminate the risk of Cloud-related cyberattacks. The main aims of this systematic literature review (SLR) are to (1) address security risks/vulnerabilities that can target cloud environments, (2) define tools that can be used by organizations to defend their cloud environment against those security risks/vulnerabilities, and (3) analyze case studies of significant cyberattacks and provide recommendations for organizations to mitigate such cyberattacks. This paper will propose a novel cloud cybersecurity model from a two-pronged offensive and defensive perspective for implementation by organizations to enhance their security infrastructure.

关键词： Cloud Computing Vulnerabilities Security Risks

Systematic Review: Analysis of Coding Vulnerabilities across Languages

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信息安全(英文) 2023年第4期14卷 330-342页

作者： shreyas Sakharkar Stevenson Ranch USA

The boom of coding languages in the 1950s revolutionized how our digital world was construed and accessed. The languages invented then, including Fortran, are still in use today due to their versatility and ability to underpin a large majority of the older portions of our digital world and applications. Fortran, or Formula Translation, was a programming language implemented by IBm that shortened the apparatus of coding and the efficacy of the language syntax. Fortran marked the beginning of a new era of efficient programming by reducing the number of statements needed to operate a machine several-fold. Since then, dozens more languages have come into regular practice and have been increasingly diversified over the years. Some modern languages include Python, Java, JavaScript, C, C++, and PHP. These languages significantly improved efficiency and also have a broad range of uses. Python is mainly used for website/software development, data analysis, task automation, image processing, and graphic design applications. On the other hand, Java is primarily used as a client-side programming language. Expanding the coding languages allowed for increasing accessibility but also opened up applications to pertinent security issues. These security issues have varied by prevalence and language. Previous research has narrowed its focus on individual languages, failing to evaluate the security. This research paper investigates the severity and frequency of coding vulnerabilities comparatively across different languages and contextualizes their uses in a systematic literature review.

关键词： CWE (Common Weakness Enumeration) Data Security Coding Vulnerabilities

Preventing the Deluge: Climate Change, the Four Spheres, Interactions, and Causalities

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Atmospheric and Climate Sciences 2023年第1期13卷 1-9页

作者： shreyas Banaji Flint Hill School NASA/Virginia Earth Systems Science Scholars Oakton USA

Climate change means water change, and the impacts of climate change cause not only global sea levels to rise, but also elicit dangerous levels of coastal and mainland flooding. This study relates the effects of climate-change-induced sea level risings to several harmful, and sometimes preventable, factors causing floods. One topic discussed here will be the ocean’s current (more specifically, “The Atlantic meridional Overturning Current”) as it continues to warm with increasing temperatures. In addition to discussing the effects of the AmOC, it also relates the increasing causes that are contributing to flooding, plus the proliferation of melt from ice sheets, ice caps, and glaciers, which inevitably contributes to the devastating effects of flooding on coastal communities, destroying habitats and contributing to the extinction of both aquatic and land animals, and even impacting human infrastructure and livelihoods. This examination additionally presents the serious implications that climate change and flooding have had on the planet’s freshwater resources and reserves, which are being further destroyed by the added influx of salt water, causing water to then be treated with aquifers, an energy-intensive and highly expensive process. Lastly, this paper provides several suggested possibilities for curbing some of the harmful effects humans have already had on contributing to climate change, as well as the environmental factors that have further caused dangerous levels of flooding.

关键词： Climate Change Flooding Toxic Algae Water Cycles Precipitation Runoff Currents Glaciers Weather

Double-face urethroplasty in patients with obliterative bulbar strictures post-transurethral resection of the prostate mid-term outcomes in high-volume referral center

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Asian Journal of Urology 2023年第4期10卷 512-517页

作者： Pankaj m.Joshi manuel Hevia Yatam Lakshmi Sreeranga marco Bandini Amey Patil shreyas Bhadranavar Vipin Sharma Sandeep Bafna Sanjay B.Kulkarni Kulkarni Reconstructive Urology Center 3Rajpath SocietyPaud RoadPune 411038India Urology Department Ramón y Cajal University HospitalIRYCISUniversity of AlcaláMadridSpain Urological Research Institute(URI) Unit of UrologyIRCCS Ospedale San RaffaeleVita SaluteSan Raffaele UniversityMilanMIItaly

Objective Incidences of post-transurethral resection of the prostate(post-TURP)strictures are between 2.2%and 9.8%.Stricture commonly occurs within the first 6 months.Our objective was to assess the outcomes of patients with obliterative strictures post-TURP that underwent a double-face urethroplasty.methods This is a single-center prospective study of 17 patients with obliterative proximal bulbar stricture post-TURP who underwent double-face graft urethroplasty by two surgeons between January 2014 and January 2020.We defined post-TURP obliterative strictures as those patients who presented with complete or almost complete obstruction of the urethral lumen and who have had a history of acute urine retention.We have excluded patients with bladder neck contracture.Primary outcome was treatment success,defined as the no need for further treatments.Secondary outcome was post-urethroplasty continent rate.Results Seventeen patients were included in the study with median age of 66(interquartile range 40-77)years;median time of follow-up was 24(interquartile range 12-84)months;median stricture length was 4(interquartile range 2-6)cm.Of the 17 patients,15(88.2%)were successful.All patients were continent after urethroplasty.Conclusion With mid-term follow-up,treatment of obliterative proximal bulbar strictures with double-face buccal mucosa graft is a safe and effective procedure.Obliterative proximal bulbar strictures merit double-face urethroplasty with high-rate success and functional outcomes.

关键词： Double-face urethroplasty Obliterative urethral stricture Post-transurethral resection of prostate Urethral stricture Spongiofibrosis Iatrogenic stricture

NASA’s mission ACTIVATE: Objectives, Strategies, and Limitations

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World Journal of Engineering and Technology 2022年第4期10卷 819-823页

作者： shreyas Banaji Flint Hill School/NASA/VESSS Hampton VA USA

The primary goal of this report is to describe the operational concepts of NASA’s ACTIVATE mission. ACTIVATE hopes to improve the understanding of aerosol dispersion and models, provide accurate data for aerosols’ characterization and ozone profiles, and establish knowledge of the relationships between aerosols and water. ACTIVATE’s science objectives are to quantify Na-CCN-Nd relationships and reduce uncertainty in model cloud droplet activation parameterizations, improve process-level understanding and model representation of factors governing cloud micro/macro-physical properties and how they couple with cloud effects on aerosol, plus assess advanced remote sensing capabilities for retrieving aerosol and cloud properties related to aerosol-cloud interactions. ACTIVATE utilizes the fixed-wing B-200 King Air to collect data. Data collected by ACTIVATE is highly relevant for meteorologists and environmental scientists looking to understand more about aerosol-cloud formations. Finally, ACTIVATE is a 5-year mission spanning from January 2019 to December 2023 and has used, and will continue to use, instruments such as the High Spectral Resolution Lidar-2 (HSRL-2), the Research Scanning Polarimeter (RSP), and the Diode Laser Hygrometer (DLH).

关键词： Atmosphere Aerosol-Cloud Interactions marine Boundary Layer NASA Activate High Spectral Resolution Lidar-2 Research Scanning Polarimeter Diode Laser Hygrometer