100 research outputs found
Centrifugal forming and mechanical properties of silicone-based elastomers for soft robotic actuators
No full textThis thesis describes the centrifugal forming and resulting mechanical properties of silicone-based elastomers for the manufacture of soft robotic actuators. This process is effective at removing bubbles that get entrapped within 3D-printed, enclosed molds. Conventional methods for rapid prototyping of soft robotic actuators to remove entrapped bubbles typically involve degassing under vacuum, with open-faced molds that limit the layout of formed parts to raised 2D geometries. As the functionality and complexity of soft robots increase, there is a need to mold complete 3D structures with controlled thicknesses or curvatures on multiples surfaces. In addition, characterization of the mechanical properties of common elastomers for these soft robots has lagged the development of new designs. As such, relationships between resulting material properties and processing parameters are virtually non-existent. One of the goals of this thesis is to provide guidelines and physical insights to relate the design, processing conditions, and resulting properties of soft robotic components to each other. Centrifugal forming with accelerations on the order of 100 g’s is capable of forming bubble-free, true 3D components for soft robotic actuators, and resulting demonstrations in this work include an aquatic locomotor, soft gripper, and an actuator that straightens when pressurized. Finally, this work shows that the measured mechanical properties of 3D geometries fabricated within enclosed molds through centrifugal forming possess comparable mechanical properties to vacuumed materials formed from open-faced molds with raised 2D features.M.S.Includes bibliographical referencesby Parth Kulkarn
Changing daily-life behaviors to directly cut greenhouse gas emissions
No full textLAUREA MAGISTRALEIl nostro pianeta sta morendo. Il cambiamento climatico è un’emergenza che richiede la nostra massima attenzione urgente. Poiché le attività umane sono aumentate molte volte in passato, dall’inizio della rivoluzione industriale a quella digitale, anche l’impatto sul nostro pianeta Terra. Man mano che la nostra popolazione e tecnologia crescevano, crescevano anche i nostri bisogni. Per soddisfare i nostri bisogni avevamo bisogno di molte risorse naturali che abbiamo estratto ed estratto dal nostro pianeta distruggendo foreste, terre e questo ha disturbato l’equilibrio naturale del nostro ecosistema. A causa dei nostri consumi abbiamo creato molti loop positivi che secondo la teoria del System Design hanno causato conseguenze devastanti. Le attività umane generano gas serra come anidride carbonica, metano, biossido di azoto, ecc. Che rimangono intrappolati nella nostra atmosfera e a causa di questi gas il nostro pianeta si riscalda come una serra. L’aumento della temperatura crea un clima più caldo, un aumento degli eventi meteorologici e disturba l’intero ecosistema naturale del nostro pianeta. Siamo nel periodo della sesta estinzione di massa in cui quasi 200 specie si estinguono ogni giorno.
Secondo il “Rapporto speciale sul riscaldamento globale di 1.5°C” dell’IPCC (gruppo intergovernativo sui cambiamenti climatici), entro il 2030 dovremo ridurre le emissioni globali di gas a effetto serra del 50%. Quindi, mentre l’anno 2019 sta per concludersi dobbiamo ancora raggiungere questi obiettivi che erano stati stabiliti nell’Accordo sul clima di Parigi nel 2015. Ora abbiamo solo il 67% di possibilità di invertire gli impatti e di raggiungere l’obiettivo di limitare l’aumento della temperatura globale a 1.5°C - 2°C.
Tutti i problemi causati dai cambiamenti climatici sono causati dall’uomo. E noi come cittadini della Terra dobbiamo prendere misure drastiche per limitare l’impatto. In quanto individui, in realtà pensiamo di non essere parte del problema e lasciamo il risparmio ai politici e al governo che non hanno fatto nulla per fermare questa catastrofe. In quanto individui, possiamo effettivamente apportare enormi cambiamenti intervenendo a partire dalla comprensione di ciò che facciamo nella vita di tutti i giorni e informandoci sul problema dei cambiamenti climatici. Per una persona media è difficile leggere relazioni scientifiche e documenti di ricerca, quindi esiste una grande opportunità nello sviluppo di un sistema di prodotti e servizi che potrebbe aiutare le persone a essere informate, fare scelte migliori, ridurre il loro impatto e fare la loro parte nella risoluzione di questo problema. Come esseri umani dobbiamo agire e il tempo è adesso.Our planet is dying. Climate Change is an emergency that needs our outmost urgent attention. As human activities have increased many folds in the past from the onset of the industrial revolution to now the digital revolution, so has the impact on our planet Earth. As our populations and technology grew, so did our needs. To fulfil our needs we needed a lot of natural resources that we mined and extracted from our planet by destroying forests, lands and this disturbed the natural balance of our ecosystem. Due to our consumption we have created a lot of positive loops which according to the System Design theory has caused devastating consequences. The human activities generate greenhouse gases such as carbon dioxide, methan, nitrogen dioxide, etc. which gets trapped in our atmosphere and due to these gases our planet warms up like a greenhouse. The temperature rise creates warmer weather, increased weather-related events and disturbs the whole natural ecosystem of our planet. We are now in the period of 6th mass extinction where almost 200 species are getting extinct every single day.
According to the “Special Report on Global Warming of 1.5°C” by IPCC (Intergovernmental Panel on Climate Change), we need to cut down the Global Greenhouse Gas Emissions by 50% by the year 2030. So as the year 2019 is almost ending we still have to achieve this goals which were set at the Paris Climate Agreement in 2015. We just have a 67% chance now to reverse the impacts and to achieve the goal of limiting the global temperature rise to 1.5°C-2°C.
All the problems caused by Climate Change are man-made. And we as citizens of the Earth have to take drastic measures to limit the impact. We as individuals actually think that we are not a part of the problem and leave the saving up to to the politicians and government which haven’t done anything to stop this catastrophe. As individuals we actually can make huge changes by taking action starting by understanding what we do in our day-to-day lives and informing ourselves about the problem of Climate Change. For an average person it is difficult to read scientific reports & research papers so there lies a big opportunity in developing a product-service-system which could help people informed, make better choices, reduce their impact and do their part in solving this problem. As humans we need to take action and the time is now
Characterization and optimization of UAV power system for aerial and submersible multi-medium multirotor vehicle
No full textEven as an emerging technology, Unmanned Aerial Vehicles (UAVs) have had a tremendous impact on the world. From the way wars are fought, to the way we take selfies, drones are well on their way to revolutionizing our daily lives. One of the most innovative applications of these vehicles in the Naviator submersible-UAV. This unique multirotor is capable of aerial flight and underwater operations with seamless Air-Water transitions. In this thesis, the power system of a multirotor UAS is characterized using standard performance models with the goal of designing and optimizing the systems of a new Naviator V5 prototype. Test beds were created to collect data on BLDC motors and propellers and their performance was assessed in air and water. Theoretical models using BEM theory and the 3-constant motor model were validated for their accuracy. Experiments found that RC air propellers are similarly efficient in air and water and BLDC motor performance is partially diminished due to the higher viscosity of water. The effects of input voltage, throttle, Kv rating, and motor size were also evaluated using motor torque curves. Using this data, an optimal power system for the Naviator V5 prototype was designed, tested, and evaluated.M.S.T.Includes bibliographical referencesby Parth V. Son
ANT COLONY OPTIMIZED ROUTING FOR MOBILE ADHOC NETWORKS (MANET)
No full textA Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without using centralized access points, infrastructure, or centralized administration. Routing means the act of moving information across an internet work from a source to a destination. The biggest challenge in this kind of networks is to find a path between the communication end points, what is aggravated through the node mobility. In this paper we present a new routing algorithm for mobile, multi-hop ad-hoc networks. The protocol is based on swarm intelligence. Ant colony algorithms are a subset of swarm intelligence and consider the ability of simple ants to solve complex problems by cooperation. The introduced routing protocol is well adaptive, efficient and scalable. The main goal in the design of the protocol is to reduce the overhead for routing. We refer to the protocol as the Ant Colony Optimization Routing (ACOR)
Contemporaneous and Causal Relationship between Returns and Volumes: Evidence from Nifty Futures
No full textEvacuation of Kobylnice village in extraordinary event
No full textCílem této práce je sestavení evakuačního plánu pro obec Kobylnice. Teoretická část přibližuje problematiku mimořádných událostí a možných následků, zpracovává dostupnou literaturu a uvádí zákony a vyhlášky spojené s evakuačním plánováním. V praktické části se autor zmiňuje o programech, které jsou použitelné při mimořádných a krizových situacích a sestavuje plán evakuace.The aim of this work is evacuation plan setup for Kobylnice Corporation. The theoretical parth explains issue of extraordinary events and possible consequences, processes available information and shows the laws and public notices are being used in evacuative planning. In the practical parth author presents programs, which are applicability to extraordinary events and crisis situations. She draws a plan of evacuation.Institut bezpečnostních technologiíobhájen
Foundations of the law on industrial organisations in Russia and the former republics of the USSR: 1985-1990
No full textThe industrial organisations introduced into the law of the USSR from 1987, and thereafter
into the law of the former republics, developed upon a foundation that was rooted in Soviet
law and was constructed during the period from 1985 to mid-1990.
While this study focuses on the industrial economy, certain aspects of the agrarian economy,
and in particular the early history and structure of the collective farm, are considered where
appropriate.
The thesis presents an entirely new understanding both of the nature of these developments
and of the significance of the law on ownership. The foundations of the law on industrial
organisations are conceptualised within specific heuristic models which are elaborated in an
attempt to consolidate and highlight the key steps in this history. It is argued that Soviet law
did not contain a concept of the "generic owner" or a developed understanding of the
ownership of a juridical person, in particular by multiple owners holding "ownership
interests" of that juridical person; and that their absence critically impaired a rational and
coherent structure for the foundations of the law on industrial organisations both within the
Stalin economic settlement and the new economic constitution of 1990
Electrochemical screening and surface analysis of environmentally friendly corrosion inhibitors for aerospace aluminium alloy
No full textFor the past few decades, the aerospace industry has been actively looking for measures to tackle the problem of localized corrosion of aluminium alloy 2024-T3. One such measure was the use of hexavalent chromium salts as corrosion inhibitors. However, recent studies have reflected the environmental concerns and health impacts associated with these compounds. Since then, there has been a quest for alternatives that can be used as corrosion inhibitors for AA2024-T3. This thesis is aimed at studying these compounds by testing their inhibitive properties. Selecting an inhibitor from a set of compounds and recommending the best one is a crucial process. The research focuses on the screening of these inhibitors through various electrochemical techniques such as Potentiodynamic Polarisation(PDP), Linear Polarisation Resistance(LPR), and Electrochemical Impedance Spectroscopy(EIS). The electrochemical experiments during the first 24-hour exposure of AA2024-T3 to inhibitors exhibited that 2,5-Dimercapto-1,3,4-thiadiazole acts as a corrosion accelerator, while Na-Mercaptoacetate and Mercaptobenzimidazole showed the most inhibitive performance among the tested organic compounds. On monitoring their nature during 24 hours, it was observed that they show stable polarisation resistance values after 6 hours. Among the inorganics, Cerium compounds were seen to have better inhibitive properties than the Lithiumcompounds. Additionally, surface studies such as Fourier Transform Infrared Spectroscopy (FTIR) revealed the presence of thiol/mercaptan and carboxyl groups on samples exposed toNa-Mercaptoacetate. X-ray Photoelectron Spectroscopy (XPS) showed oxides of Cerium on samples exposed to Cerium Nitrate. Finally, the correlations between the inhibition efficiencies calculated from different electrochemical testing methods were illustrated using Pearson’s correlation method.Materials Science and Engineerin
Towards Designing Reliable and Efficient Millimeter-Wave Wireless LANS
No full textWith the increasing amount of mobile data and the demand for high data rates, current 2.4GHz/5GHz wireless local area networks (WLANs) are facing the problem of limited capacity. Millimeter-wave (mmWave) networks with gigahertz of channel bandwidth can provide multi-gigabit per second data rates, making it possible to support novel applications such as augmented/virtual reality (AR/VR), mobile offloading, high-resolution video streaming, etc. However, despite the potential, the directional nature of mmWave WLAN makes it prone to blockages and mobility. The dense deployment of Access Points (APs) brings unpredictable interference and non-negligible beamforming overhead. Moreover, current mmWave WLANs are application agnostic, resulting in inefficient usage of resources in supporting AR/VR type bandwidth-intensive applications. In this dissertation, I propose novel solutions to four key challenges, aiming to build practical, reliable, and efficient mmWave WLANs. Firstly, I explore a proactive blockage mitigation technique that utilizes joint transmissions of multiple APs to provide blockage resilience. Secondly, I characterize interference in dense mmWave WLANs and implement three interference mitigation techniques using commercial-off-the-shelf (COTS) devices. Thirdly, focusing on reducing the beamforming overhead, I propose a “Networked beamforming” model to reduce the number of APs that conduct beamforming in dense mmWave WLANs, resulting in significant improvements in network throughput. Lastly, I design novel solutions for blockage prediction and prefetching based on users’ six-degree-of-freedom (6DoF) position and orientation information to facilitate high-quality volumetric video streaming over mmWave WLANs.This work is embargoed by the author and will not be publicly available until 2024-08-31.2024-08-3
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