28 research outputs found
Topics on electron,neutrino and axion scattering
No full textThesis: S.M., Massachusetts Institute of Technology, Department of Physics, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from PDF version of thesis.Includes bibliographical references (pages 61-64).Under the broad topic of scattering, in this thesis we particularly investigate Lorentz invariance using Compton Scattering at the Compton Polarimeter located in Hall-C at Thomas Jefferson National Accelerator Facility. The Mississippi State Axion Search, an axion search experiment which uses light shining through a wall technique is described in detail, including its instrumentation, initial tests and future impact. Furthermore, a novel method of detection of solar anti-neutrinos based on coherent neutrino scattering is described. Additionally, on the instrumentation side, development of a multi-purpose beam instrument based on synchrotron light to measure the electron beam polarization, beam profile and intensity at the future Electron Ion Collider is presented.by Prajwal Mohanmurthy.S.M
MDO framework for university research collaboration: AGILE academy initiatives & outcomes
No full textAGILE Project is developing the 3rd generation MDO processes, which will support the development of the next generation aerospace products. The establishment of effective collaborative design methodologies is currently acknowledged as the key enabler for future product development processes. At the same time, the need to introduce collaborative design techniques within educational activities is also well recognized by the Academic, Research and Industrial communities. AGILE project supported by European Commission’s H2020 Programme, is setting the “AGILE Paradigm”, a conceptual framework which contains all the elements to implement a multidisciplinary collaborative design network. The AGILE Academy initiative is conceived to infuse into the Academic organizations and educational environments the “AGILE Paradigm”, and make available all the technologies developed within the AGILE Project, which support the implementation of such a Paradigm. This paper focus is on the inception, approach and results of the AGILE Academy participants from several universities around the world
Modeling and simulation of thermal runaway phenomenons in commercial Li-ion battery cells
No full textLi-ion batteries, while widely adopted, exhibit complex behaviours under extreme conditions that can lead to thermal runaway, a hazardous phenomenon responsible for battery failure and significant safety concerns. The research is motivated by
the critical knowledge gaps in the understanding of battery thermal runaway. The limited exploration of the rapid reactions occurring during battery failure, the absence of a specified triggering temperature, and the insufficient understanding of the role of gas formation and gas venting, collectively prompted a deeper investigation.
This thesis is focused on gaining a deeper understanding of battery thermal runaway at the cell level. To achieve this, GT-SUITE is utilized to create two models that replicate Accelerating Rate Calorimeter (ARC) battery testing and investigate heat generation and gas venting. The first model combines electrochemical and thermal aspects and analyzes stages of thermal runaway by discretizing them on a cell temperature scale. Such a model not only defines the sequence of events but also calculates the total heat generation for each stage, focusing on the analysis of anode and cathode rapid reactions and their influence on the thermal runaway. The results are validated with experimental results and found to exhibit good accuracy.
The second model specifically focuses on gas venting, capturing released gases and analyzing mass loss in the battery cell. Overall, the research presents a detailed analysis of Li-ion battery thermal runaway phenomena while providing temperature
and reaction rates boundary conditions for pack-level analysis
Detailed Drug Information on Etoposide: A Comprehensive Guide
No full textEtoposide is a chemotherapy drug that is used in the treatment of various types of cancer, including testicular, ovarian, lung, and gastric cancer. This powerful chemotherapy drug is known for its ability to target rapidly dividing cells and stop the growth of cancerous tumors. However, as with any medication, it is important to have a thorough understanding of the pharmacokinetics and pharmacodynamics of the drug, as well as its potential drug interactions, adverse drug reactions, and indications for use. In this article, we will explore these topics in detail, providing you with the information you need to understand the full spectrum of the drug.S P Srinivas Nayak et al. Ijppr.Human, 2023; Vol. 26 (3): 394-400
NUMERICAL ANALYSIS OF IMMERSION COOLING ON A SERVER USING AL2O3/MINERAL OIL NANOFLUID
No full textIn the current world, technology has developed significantly, with a massive processing and storage of data, resulting in the high increase in Power Density and Heat Generation of servers, computers and its components in data centers. This calls for an engineering solution, for efficient heat dissipation of these servers to ensure their reliability and prolonged working. Air cooling is a prominent method of data center cooling. However, due to its low heat carrying capacity, it is not an efficient method for cooling high heat generating servers. There are two methods to remove this heat, increasing the area of heat transfer being one of the methods, which is not feasible everywhere. To tackle this problem, liquid immersion cooling method has emerged as a prominent method for cooling servers and its components in data centers, where the servers can directly be immersed inside the liquid, making the process simpler and cost effective. Water has higher thermal properties like heat capacity, but the limitation is that the liquid must be dielectric to save equipment from short-circuit. This feature also influences the thermal conductivity of the liquids. Generally dielectric liquids have low thermal conductivity which affects the thermal performance of the cooling process. Thermal conductivity of the dielectric liquids is drastically increased with the introduction of nano particles, which has proven to be the best method. Nano particles are metal and non-metal particles with the size between 1 to 150 nano-meters. To keep the dielectric feature of the liquid, the non-metallic nano particle can be added to the liquid. Therefore, the Alumina which is one of the materials using as an electrical insulation is used. The mean size of the nano particle used in this work is 80 nm and the liquid are mineral oil, which is a low-price liquid for immersion cooling compared to other dielectric liquids. The concentration of nano particles was 0 to 5 percent and it is assumed to remain homogeneous. The properties of the mixture were calculated based on the theoretical formula and it was function of temperature. In this work, we simulated heat transfer and effect of the nano particle concentration on the junction temperature of the processors using CFD techniques. The chosen server is an open compute server which has two processor in a row. The server was modeled in Ansys Icepack and simulations were performed for pure mineral oil and nano-fluid at particle concentrations of 1%, 3% and 5 % at 1, 2 and 3 LPM respectively. Prior to the study, effect of frame height on the maximum CPU junction temperature was tested using pure mineral oil. Drastic reduction in maximum CPU temperature was observed with a smaller frame height and this height was maintained throughout the study. Simulations were conducted for 3 different heatsink geometries, namely parallel plate, cylindrical bonded pin and plate fin heatsink. From results obtained, effect of nano-particle concentration on the maximum CPU junction temperature, pressure drop and pumping power were studied and comparisons were made for different nano-particle concentration and flow rates. Also, comparisons on CPU junction temperature, pressure drop, and pumping power obtained from simulations using the 3 different heatsink geometries were made
Comprehensive analysis of the impact of pre-processing techniques on the performance of a cnn-based facial age estimation model
No full textFacial age estimation has been a complex task in the field of computer vision due to the factors such as variations in the facial appearance, complex aging pattern and the lack of a standard knowledge as to the basis of what really constitutes towards calculating the age using facial features. With the ever improving technology, Convolutional Neural Networks (CNNs) have been proven to be the most powerful solution the facial age estimation problem. We aslo need to note that the performance of these models heavily depend on the the quality of the images that they are trained on. Fortunately, certain pre-processing techniques in the field have shown that they can improve the performance of these models by enhancing certain features in a photo. In this research paper, we try to provide a comprehensive analysis of the impact of various, commonly used pre-processing techniques in the computer vision field over the performance of a CNN-based facial age estimation model. Specifically, we investigate the effectiveness of Image Rescaling, Histogram Equalization, Gaussian smoothing, and Grayscale conversion techniques on three widely used datasets, namely UTKFace, MegaAge, and FGNet. Our experimental results indicate that preprocessing techniques have a significant impact on the performance of the age estimation model. Among the techniques studied, Histogram Equalization is found to be the most effective in improving the accuracy of the model on all three datasets. and Gaussian smoothing and Image Rescaling techniques come close to the positive impact of Histogram Equalization but just fall short. Image Rescaling was successful only on the FGNet dataset. Although it didn't show a significant improvement in the performance of the model, it improved its time and memory used during the compilation. Furthermore, it was noticed that the impact of these pre-processing techniques varied depending on the dataset being considered. For instance, the Histogram Equalization technique is found to be most effective on UTKFace. Whereas, Image Rescaling came out on top for the FGNet datasets and Gaussian smoothing showed it is most effective on the MegaAge dataset. The findings in our work contain important comparisons for the researchers in the field of computer vision especially in the field of facial age estimation. This work will give them an idea and guidance towards picking the best pre-processing techniques to enhance the quality of the images for the specific dataset they're using enabling them to extract the maximum potential of the the age estimation they're using
Not Available
No full textNot AvailableInvestigations were carried out to study the effect of precooling and preservative chemicals on post harvest longevity of the florets of tuberose (Polianthes tuberosa L.) cv. Prajwal. The effect of precooling of tuberose florets in combination with four chemical treatments were studied and observations were recorded based on quality parameters like freshness of the florets, colour retention, physiological loss in weight and days to fifty per cent wilting. Pre-cooling of flower buds was found to improve the longevity (shelf life) of flower buds. Soaking of florets in 4 % Boric acid solution for two hours and air drying them before packing increased the shelf life up to six days.Not Availabl
Low-cost uni-directional PFC for 3-phase systems
No full textPower consumed by any equipment connected to the grid must be regulated to facilitate the reliable and efficient operation of the grid and for smooth equipment operation of other consumers. Power factor is one of the major power quality measurement tool. All the electrical equipment connected to the grid must comply with the power factor limits as specified under various standards. This thesis aims at the development of a cost-effective power factor correction converter for a motor drive with a power range up to 10 kW, which is also robust for line and load transients.Electrical Engineerin
Cylinder Drag Reduction Using Discrete Surface Roughness: An Experimental Investigation Into the Effect of Cylindrical Roughness Elements
No full textThis thesis investigates the influence of Cylindrical Distributed Roughness Elements (polka-dots) on cylinder flow, with a focus on potential applications in sports aerodynamics. The primary goals are twofold: to explore the mechanism behind tripping and to analyse how the dimensions (height, width, spacing) of polka-dots affect flow characteristics. The research employs an experimental approach, utilising balance measurements to quantify drag within the relevant Reynolds number range experienced by the limbs of speed-skaters. Additionally, Particle Image Velocimetry (PIV) measurements are conducted to examine the boundary layer and wake flow, revealing insights into how different polka-dot geometries impact flow characteristics.11 polka-dot configurations were tested wherein the polka-dot height, diameter and spanwise (flow-normal) spacing was varied. Two PIV domains were imaged: the boundary layer flow before and after the polka-dot (covering an azimuthal range of about 40◦ of the circular profile), and the wake domain of the cylinder (about 2 diameters into the downstream flow). The boundary layer flow images were used to characterise the flow seen by the polka-dot array, and how it is affected by changes in the polka-dot geometry. The wake domain PIV imagery was used to examine the shape and dimensions of the cylinder wake.Among the 11 tested polka-dot configurations, 10 effectively triggered drag reduction to varying extents within the relevant regime. The minimum drag coefficient was achieved by the configuration with the polka-dots of greatest diameter. It was also seen that increasing polka-dot height is likely to cause premature separation which is further exacerbated by a narrower polka-dot spacing. In general, results indicate that shorter and wider polka-dots cause transition at lower Reynolds numbers, and a greater reduction in drag occurs when transition takes place at higher Reynolds numbers. Polka-dots placed in closer proximity initiate flow tripping earlier, while wider spacing results in more substantial drag reduction. However, it is observed that the polka-dots, when spaced closer together, see a lower flow velocity for the same polka-dot height and may lead to premature separation.In terms of the wake width, a high linear correlation is seen between the measured wake width and the measured coefficient of drag (r2 ≈ 0.9). It is also seen that for drag coefficient values close to the minimum drag coefficient value, the wake width sees minimal change. The change in wake geometry is then seen as a change in the wake tapering (downstream decrease of the wake width) and the streamwise wake length. Therefore, a larger wake imaging domain in the streamwise direction is likely to allow for a more accurate correlation of the wake geometry and the drag coefficient.While the study offers valuable insights, several recommendations are put forth for further research. Expanding the wake imaging domain is suggested to enhance correlations with the drag coefficient, and investigating spanwise flow variations would provide deeper insight into the tripping mechanism.Aerospace Engineering | Aerodynamic
Influence of Parametric Modelling of Wing Subsystems on the Aircraft Design and Performance
No full textAircraft design methodologies have been significantly developing from the past few years with the advancements in knowledge based techniques. These methods enable the storage of design knowledge and rules, and reuse them to create different types of designs, thus preventing the designer to perform repetitive tasks. Tasks such as parametric modelling of components, such as the aircraft wing can be automated by storing the modelling processes and the design rules in a knowledge base. With this process, variants of the wing with different geometric parameters can then be generated in a short duration by simply varying certain top-level requirements. It is necessary to extend these design techniques to model aircraft systems in the conceptual design stage. This, not only decreases the time of design realisation but also presents a scope to assess the effects of various inter-dependencies due to systems and make appropriate changes, in the early stages of aircraft design. Developing and demonstrating a framework which aids to assess the influence of the wing subsystems, namely the flight control actuators, fuel tanks and anti-ice elements; on the aircraft design and performance in the conceptual design stage is the aim of the thesis. This thesis presents a combination of physics based and knowledge based design methodologies to size the wing subsystems and position them in the airframe. Consequently, the methods are integrated into the conceptual aircraft design process to enable multidisciplinary design with supporting domains. The methods are aimed to aid the design of conventional systems architectures and More Electric Aircraft (MEA) systems architectures as well. With these methodologies, the Systems Model Generator (SMG) application is developed in Python to facilitate semi-automatic wing subsystems sizing and orientation in the airframe based on top-level aircraft requirements, initial aircraft design parameters and system specific parameters. The subsystem models generated with the proposed methodology for short-medium range civil transport aircraft are verified and validated as well. Knowledge based systems and subsystems selection are implemented to facilitate semi-automated systems, subsystems and architecture selection, based on the aircraft configuration and systems specific requirements. Methods for automatic iterative fuel tanks sizing and intersection detection are implemented to further reduce the overall design time and make the tool more suitable for integrated sizing.With the multidisciplinary design framework, the conceptual parametric models, volume, mass, power consumption and position of the subsystems in the airframe are generated and propagated in the conceptual aircraft design stage; thus bridging the conceptual and the preliminary design stages. In the proposed framework, the domains of aircraft design generation, systems selection and sizing, subsystems selection and sizing, engine sizing and mission simulation are considered for the multidisciplinary design process. The domains are integrated with the DLR CPACS-RCE framework. A case study to demonstrate the process of integrated parametric subsystems sizing of the aircraft, with the proposed framework is presented. The aim of this case study is to assess the influence of the MEA systems architecture relative to the conventional systems architecture for a short-medium range transport aircraft, similar to the Airbus A320-200. In this case study, the quantitative influence of the subsystems' parameters on the aircraft design and performance parameters is determined and analysed. The subsystems' parameters constitute the mass, power consumption, volume and location of the subsystems in the airframe and the aircraft design parameters constitute the aircraft masses such as the overall empty mass and the fuel mass for the mission. The generation and propagation of the design and performance parameters of the aircraft through each domain of the framework are presented and analysed as well with the case study. In this case study, it is observed that the MEA systems architecture results in a lower mission fuel mass relative to the conventional systems architecture by nearly 2.3\%. Furthermore, these results are compared with literature and observed to be in the similar range of 2-7\%. Thus, the validated aircraft design framework presented in this thesis enables to substantially increases and propagate the design knowledge of aircraft systems, in the early design stages.AGILEAerospace Engineerin
