89 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
Transient Thermal Analysis of Brake Disc in Regenerative Braking System Using Finite Element Analysis
No full textRecommended from our members
Sub-50nm roll-to-roll nanoimprint lithography for manufacturing high-index inorganic nanophotonics
No full textPhotonic devices such as diffractive optics and metasurfaces are increasingly being utilized in extended reality (XR) displays and flat optics. High refractive index materials are the ideal choice in which nanostructures need to be fabricated for these applications. In addition, the desired patterns comprise of complex geometries such as slanted or multitiered nanostructures and variable pitch nanostructures with minimum feature size that is on the order of 1/10th or less of the operational wavelengths with aspect ratios approaching 10:1. Many of the current XR products in the market utilize direct nanoimprint of polymers with refractive index (RI) of 1.5-1.7 in the visible spectrum. Extending to higher RI beyond this using imprintable polymers has faced scalability challenges due to limitations in polymer material properties as well as inconsistent optical performance due to material variability, particularly over the lifetime of the device. Inorganic high-index materials can lead to best-in-class performance and reliability in these devices. However, etching of these nanoscale features in high-index substrates is difficult due to the inability to create volatile reactants during reactive ion etching requiring the use of ion milling which is known to be defect-prone. In addition, uniformity of etched geometries in nanoscale features with high aspect ratios and 3-dimensional geometries is critical as variations can significantly diminish the optical properties of these devices. In this dissertation, a scalable fabrication method for high-index inorganic waveguides and metasurfaces is explored that circumvents the need for etching nanoscale features in high-index materials. The key elements of this dissertation that contribute to the above capability are as follows: • Precision machine design for achieving continuous R2R nanoimprint for sub-50 nm high-throughput nano-manufacturing with sub-25 nm residual layer thickness • Plate-to-Roll (P2R) nanoimprint that enables the creation of a roll-based working template that is used in the above R2R nanoimprint equipment to allow long template life in volume manufacturing • Enhanced precision in nanofluidic-based processes such as nanoimprint lithography by incorporating spatiotemporal thermal actuation that could potentially address systematic nanoimprint defects during high speed patterning • A process that uses a switchable adhesive layer that can create detachable nanostructures with a deposited high-index material followed by precision layer transfer to enable the desired optical componentsMechanical Engineerin
Trataka: A Promising Intervention to Reduce Anxiety in Children? A Randomized Controlled Trial with Cognitive and Electrodermal Measures
No full textBackground:
One in five children suffers crippling dental anxiety, and traditional calming methods often fall short. Trataka, an ancient yogic technique, offers a powerful new approach to manage this anxiety.
Objective:
The objective is to investigate whether Trataka practice is more effective than relaxation techniques in reducing anxiety in children undergoing dental procedures.
Methodology:
A two-arm, parallel-group, randomized controlled trial was conducted with 120 children aged 8–11 years requiring local anesthesia for dental procedures. Participants were randomized to either a Trataka group (n = 60) or a relaxation techniques group (n = 60). Both groups received 4 weeks of training on their assigned intervention. The primary outcome was anxiety level measured by the Mood and Anxiety Symptom Questionnaire (MASQ) administered pre- and postintervention. Secondary outcomes included electro-dermal activity (EDA) test results and the Stroop Colour Word Test (SCWT), both performed pre- and postintervention, and observed anxiety-related behaviors during procedures.
Results:
Children in the Trataka group exhibited a significantly greater reduction in anxiety compared to the relaxation techniques group, as measured by the MASQ score (P < 0.001) and lower EDA response during the SCWT (P < 0.01). The Trataka group also displayed fewer observed anxiety-related behaviors during procedures (P < 0.001).
Conclusions:
The findings suggest that Trataka may be more effective than relaxation techniques in reducing anxiety in children undergoing dental procedures
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
Under-diagnosis of asthma in elderly
No full textIntroduction: The concept of asthma affecting the old age people has been universally denied in past. Therefore, rather than suspecting asthma in old age patients, it often gets misdiagnosed as chronic obstructive pulmonary disease (COPD), leading to sub-optimal management of disease. Considering the fact that only one in five life-long smokers ever develop COPD, we must not blindly diagnose it in elderly smokers without going through clinical evaluation. Spirometry can be helpful in differentiating asthma; however, demonstration of small degree of reversibility to bronchodilators alone does not distinguish asthma. Comorbidities in old age or the drugs taken to treat them may exacerbate asthma. Conversely, bronchodilators and corticosteroids used to treat asthma often worsen these co-morbid conditions, such as osteoporosis, diabetes mellitus, and cardiac arrhythmias - making our regimens even narrower. Objectives: To highlight the misdiagnosis of asthma in old age. Materials and Methods: A prospective study was done involving 350 clinically diagnosed obstructive airway diseases (OADs) patients at SBKS Medical Institute and Research Center and their evaluation was done. Results: Out of 350 patients clinically appearing as OAD, 292 had obstructive pattern in pulmonary function tests; from which 100 were found to be asthmatic and 192 were of COPD. Out of these 100 diagnosed asthma patients, 16 were of age more than 60 years, from which five were previously treated as COPD. Conclusion: There is considerable prevalence of asthma in old age too, which, if misdiagnosed, can lead to sub-optimal treatment of the asthma
Evacuation 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
From impression to addiction: The pathways of adolescent tobacco use
No full textAim: To understand the psychodynamics of tobacco use among 11- to 14-year-olds in Ahmedabad, India. Materials and Methods: A self-administered questionnaire was used to gather information on tobacco use from 5,266 students, aged 11 to 14, enrolled in government-aided English medium schools in Ahmedabad. IBM® SPSS® 26.0 software along with Chi-square tests were used to analyze the data. Results: A total of 7.2% (376) had ever used tobacco. Of the users, 96.6% (363) knew it was harmful, 76.3% (287) were boys, and 85.2% (320) were initiated by family and friends. Conclusion: Despite being aware of the dangers of tobacco and being unable to purchase from vendors, children continued to obtain tobacco products, being influenced by their close social networks. An effective cessation measure should be directed toward this psychodynamic etiology
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