68 research outputs found
Broadband mm-wave signal generation and amplification in CMOS using synthetic impedance
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 75-76).This thesis explores the concept of synthesizing tunable impedances by establishing the appropriate phase relationship between the drain voltage and drain current of a MOS transistor. A high frequency, wide tuning range 105-121GHz oscillator and a small-footprint 20-40GHz oscillator using synthetic resonance are presented. The concept of impedance synthesis is also used to generate a novel frequency-adaptive loss compensation scheme for distributed amplifiers which is shown to improve the bandwidth by 30%. The performance of these circuits was analyzed and simulated on a TSMC 65nm bulk CMOS process.by Pranav R Kaundinya.M. Eng
Characterization of Epoxy Modified Asphalt
No full textAsphalt pavements serve as the foundation of our transportation system, and their
durability and effectiveness heavily rely on the properties of bitumen, which acts as the
adhesive agent binding the aggregate materials together. Modified asphalt binders offer
improved performance by enhancing the mechanical characteristics and resistance to
rutting and fatigue of asphalt pavements.
Epoxy resin is a type of synthetic thermosetting polymer that is widely used in various
industries and applications. It is created through a chemical reaction between epoxide
monomers and a curing agent, typically a hardener. The resulting material is a highly
durable and versatile substance with a wide range of properties.
This study aims to investigate the impact of epoxy modification on asphalt binder &
mixtures properties. The base bitumen (VG 30) was modified by incorporating epoxy
(combination of epoxy resin and hardener) at different contents of 1%, 2%, 3%, and 4%
by weight of heat binder. The rheological properties of the binders were evaluated
through tests such as high-performance grade (PG), MSCR (multiple stress creep and
recovery), frequency sweeps, temperature sweeps, amplitude sweeps, SFP (Superpave
fatigue parameter), LAS (linear amplitude sweep), and BBR (bending beam rheometer)
tests. The mixture properties were tested through Marshall stability, ITS (indirect tensile
strength), and TSR (tensile strength ratio) tests.
Through comprehensive analysis, the optimal dosage of the additive was determined to
be 2-3% by weight, resulting in the most favourable modified asphalt binder and mixture
properties. Pavement structural analysis showed that the selected pavement composition
had the ability to resist higher traffic based on rutting and fatigue criteria as per IRC: 37-
2018 when epoxy-modified bituminous concrete (BC) mixtures were used in the wearing
course, than the mixture with unmodified VG 30 binder
Homogeneous catalyst mediated glucose mutarotation studies using vibrational spectroscopy
No full textThe pitfalls of overdependence on fossil fuels are well documented. Current research aims to focus on biomass obtained from renewable cellulose for the production of fuels and chemicals. In that regard, with cellulose as source, 5-hydroxymethylfurfural (HMF) is a versatile platform chemical for the production of chemicals like levulinic acid. The isomerization of glucose to fructose is one of the steps in the synthesis of HMF from cellulose. Glucose exists in several anomeric forms and it has been shown that the isomerization reaction is anomer specific. This work focuses on the study of mutarotation in glucose in the presence of homogeneous Lewis acid catalysts. A combination of spectroscopic tools: ATR-IR and Raman spectroscopy are used to study the vibrational modes of glucose in aqueous solution. At room temperature, changes in vibrational modes can be attributed to the mutarotation reaction. This work compares the rate of mutarotation in different concentrations of AlCl3, CrCl3 and SnCl4. The influence of metal salts in solution, pH and ionic strength were also probed by comparing with the rates obtained in Brönsted acids. The mutarotation in Lewis acid is faster than that in water. It is fastest in SnCl4 and increases with increase in concentration of SnCl4. Results also indicate a lack of glucose-Lewis acid interactions. However, rates vary depending on the nature of metal salts in solution indicating that the mutarotation is influenced by the nature of Lewis acid-water interactions.M.S.Includes bibliographical referencesby Pranav Rames
Do share pledges by insiders influence firm performance and value?
No full textThe first chapter demonstrates the prevalence and importance of pledging of shares by insiders in the U.S. I create the first comprehensive database of share pledges by insiders in the U.S. to reveal the prevalence of this practice and its role in encouraging earnings management. I find that, during the fiscal years 2006 to 2014, insiders at one of every three S&P1500 firms pledged their ownership in the firm as collateral to obtain loans at least once. I exploit a 2012 market-wide advisory against share pledges by Institutional Shareholder Services, the largest proxy advisory firm, as a quasi-natural experiment. A difference-in-differences estimation reveals that, after the shock, insiders curtailed share pledge activity by approximately 40% and firms with share pledges reduced earnings manipulation by an average 15% of their reported profits. The results suggest that share pledges distort the incentives of insiders and motivate them to inflate earnings.
The second chapter segregates the two types of share pledges and shows that they have divergent effects on firm performance and value. Insiders pledge their ownership in the firm to offer collateral for not only their personal loans but also the loans to the firm. Pledging of shares modifies their payoff structure without altering their control rights. This modification in the payoff structure can influence the incentives of controlling shareholders and have real effects on the firm's value and performance. Using hand-collected data from India,I find that share pledges for personal loans reduce the effective ownership of controlling shareholders and destroy firm value. In contrast, share pledges for firm's loans mitigate borrowing constraints for the firm and add value to firms with limited access to debt finance or high growth opportunities.
The third and last chapter documents that share pledges by insiders create moral hazards by motivating them to alter the risk-taking ability of firms and encouraging them to avoid reporting small losses. During the years 2009 to 2015, firms in India displayed a higher tendency to avoid reporting small losses by converting them to small profits when their controlling shareholders pledged shares. Share pledges for personal loans and firm's loans have contrasting effects on the aggregate risk-taking ability of firms. Share pledges for personal loans predict a decline in the risk-taking ability of firms over the subsequent year. On the contrary, share pledges for firm's loans may lead to excessive risk-taking.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Pranav Singh, accepted the attached license on 2019-04-07 at 18:54.The student, Pranav Singh, submitted this Dissertation for approval on 2019-04-07 at 19:05.This Dissertation was approved for publication on 2019-04-12 at 07:42.DSpace SAF Submission Ingestion Package generated from Vireo submission #13508 on 2019-08-22 at 16:20:51Made available in DSpace on 2019-08-23T20:44:39Z (GMT). No. of bitstreams: 2
SINGH-DISSERTATION-2019.pdf: 1321352 bytes, checksum: 1b00d9f433e722c1273016276b719f37 (MD5)
LICENSE.txt: 4209 bytes, checksum: 5f96c7408b374276fbaebbc846b3b679 (MD5)
Previous issue date: 2019-04-12Embargo set by: Seth Robbins for item 112285
Lift date: 2021-08-23T20:44:50Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112285
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112285
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112285
Lift date: 2021-08-23T20:48:32Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112285 on 2021-08-24T09:15:31Z
Data for Contrasting action and posture coding with hierarchical deep neural network models of proprioception
No full text#############
Contrasting action and posture coding with hierarchical deep neural network models of proprioception, eLife 2023
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Authors: Kai J Sandbrink, Pranav Mamidanna, Claudio Michaelis, Matthias Bethge, Mackenzie W Mathis and Alexander Mathis
Affiliation: Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Switzerland, The Rowland Institute at Harvard, Harvard University, United States; Tübingen AI Center, Eberhard Karls Universität Tübingen & Institute for Theoretical Physics, Germany
Date of upload: December, 2024
Earlier the data was available via dropbox (see github).
Link to the eLife article:
https://elifesciences.org/articles/81499
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Here we provide the data and code for this project:
We share the proprioceptive character recognition dataset (contained in 'pcr_data.zip') it has approximately ~29GB when uncompressed.
We share the weights of all the trained networks (contained in 'network-weights.zip'): about ~3.5GB
The compressed code is also available here ('DeepDrawCode.zip').
The activations are shared in a separate Zenodo project (due to the size). Check out the repository below to find the link.
The up to date code is at: https://github.com/amathislab/DeepDraw
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The datasets, weights, activations and predictions are released with Creative Commons Attribution 4.0 license.
If you find this useful, please cite:
@article{sandbrink2023contrasting, title={Contrasting action and posture coding with hierarchical deep neural network models of proprioception}, author={Sandbrink, Kai J and Mamidanna, Pranav and Michaelis, Claudio and Bethge, Matthias and Mathis, Mackenzie Weygandt and Mathis, Alexander}, journal={Elife}, volume={12}, pages={e81499}, year={2023}, publisher={eLife Sciences Publications Limited}}UPAMATHISUPMWMATHI
Study of Electrochemical Performance of Lithium and Zinc Metal Anodes for Rechargeable Batteries
No full textMetal anode based batteries, considered the ideal upgrade to Lithium ion batteries in terms of energy density, are currently held back by the non-homogeneous deposition phenomenon that leads to the formation of dendrites that short circuit the cell. The solution to this problem is twofold: while it is important to come up with solutions that mitigate/resist dendrite formation, it is more important to fully understand the deposition phenomena in metal anodes through experiments and theoretical analyses. This study aimed to first understand the deposition mechanism in Zinc and Lithium metal anodes, and then study the feasibility of polymer coatings based on Sulfonated Poly Ether Ether Ketone (SPEEK) as a solution to mitigating the dendrites.The electrochemical performance of Zinc in ZnSO4 electrolyte systems was studiedfor a wide range of current densities and for different operating conditions with the help of operando microscopy and ex-situ SEM. Further, the mechanism of initial Zinc deposition was visualized with the help of in-situ TEM. The origins of the different types of morphology observed at these conditions were explained on the basis of competition between the mass transfer and the kinetics for control over the overall process. Further, a proof of concept was established for the use of SPEEK based coatings on Zinc metal, and the electrochemical performance of polymer coated Zinc electrodes was analyzed.In the case of Lithium, the deposition in carbonate based electrolytes was first studied with the help of operando microscopy for Bare Lithium. Operando microscopy was also carried out to study the influence of the SEI, the separator and a standard polymer coating (PVDF) on Lithium deposition. Further, Lithiated SPEEK was used as a polymer coating on Lithium, and itwas observed that a more even Lithium deposition takes place with the Li-SPEEK coating on Lithium. Slight improvements were observed in the Li+ conductivity of the coating with the addition of TiO2 nanofiller to the polymer. However, performance issues were observed with long term cycling, possibly due to the instability of the polymer coating in carbonate electrolytes over long periods.Electrical Engineering | Sustainable Energy Technolog
Identification of Quasi Normal Modes: In Wave-Field Problems
No full textQuasi-Normal Modes (QNMs) are a key concept in reduced-order models. In this thesis, we use Finite-Difference approach to create a discretized model of an open electromagnetic system in order to identify its QNMs and the Perfectly Matched Layer (PML) modes. We develop a structure of the QNMs and the PML modes and identify different regions of the eigenvalue distribution in our system. We validate the idea of dominant QNMs by using the identified QNMs to get the solution that was obtained using the Finite-Difference method.Electrical Engineering | Circuits and System
The Extent of Private participation in European Mission Oriented-innovation Policy: An exploratory analysis of the CORDIS database
No full textThe advent of the 21st century has seen economies worldwide increasingly investing towards developing smart and sustainable innovations for addressing social and environmental challenges such as climate change, adapting to demographic change, public health care an well-being etc. These challenges, often referred to as 'grand challenges' are extremely complex in nature and require dynamic collaborations between the state and private actors to explore and exploit new areas of growth, and develop suitable solutions for the same. Through mission-oriented innovation, policy makers provide a framework for systematically implementing mission-led research to bring together the willing public and private actors to create system-wide transformations across the entire value chain.By virtue of its abundance of knowledge, skills and resources, the European Union provides a fervent ground for implementing mission-oriented innovation to address grand challenges, but this fragmentation could also make it an extremely complex scenario to do the same. However, through public funds such as the Horizon 2020 framework programme, the public sector can provide a foundation for initiating mission-oriented policies by funding the early, high-risk and uncertain stages of innovation, which private organizations and SMEs can capitalize on to develop smart innovations. In order to do so, the public sector must possess the appropriate set of dynamic capabilities for bringing private actors to actively work towards developing solutions for addressing grand challenges. Additionally, the fragmentation of knowledge and skills available across member nations of the European Union, industrial sectors or technologies differ, making it highly probable that the degree of private participants in mission-oriented innovation also differs.This thesis identifies the extent of private participation in European mission-oriented innovation by qualitatively analyzing data extracted from the European Commission's Community Research and Development Information Service (CORDIS) database. A descriptive statistical analysis of the data extracted from CORDIS has identified the current degree of private participation in initiatives encompasses in the Horizon 2020 framework programme. This study identifies the proportion of private participation in the various member states of the European Union and across different societal challenges. It also, identifies the participation of SMEs and incumbent in these initiatives. Based on the results obtained, this study discusses its implications for mission-oriented innovation and provides a scope for possible areas for future studies. Additionally, this study goes one step further to analyze the CORDIS database to understand it benefits and shortcomings.Lastly, this study also provides recommendations for steering policies in a more effective to better suit actors/researchers/policy makers from specific regions or sectors. The results can be utilized by researchers to conduct studies to identify the dependent variables that directly affect the participation of private actors, which can open up areas of research to understand what factors drive the participation of actors in mission-oriented policies. It also provides insights on the possibilities of using the CORDIS database for steering mission-oriented research.Management of Technology (MoT
Computational Imaging for Earth Surveillance
No full textCameras are used in various applications and one such common application has been space. Delfi Space is the CubeSat Development program of the Delft University of Technology and a subprogram of Defi-Space is Delfi-PQ which aims to develop PocketQubes which are an order of magnitude smaller than the CubeSat standards. One of the advanced payloads that would potentially be a part of the Delfi-PQ is an imager/camera. The imager needs to be as small as possible in order to fit into the Delfi-PQ satellites. The design of the camera has remained the same throughout the years and one of the reasons that increase the thickness of the camera is the presence of lenses. A way to reduce the size of the camera would be to remove the lens out of the equation. However, this introduces additional problems and trade-offs in the camera. These lenses can be replaced by masks/coded apertures. One of the additional steps in using coded-apertures is that additional computational steps need to be performed in order to reconstruct the image. The kind of computation that needs to be performed depends on the kind of masks that would be used. In this thesis, a separable mask is chosen and computer simulations on separable masks have been performed. Two image sensors that can be used in the picosatellite were chosen for implementation and the hardware/software is designed and developed. The experimental setup for determining the field of view of a lensless camera has been developed and tested. One of the trade-offs observed through the experiments is that the acceptance angle of a lensless imager had reduced by 38 percent and 31.8 percent in the horizontal and vertical directions compared to a conventional lens-based system. Based on the experimental results, the field of view of the camera has also been determined. A singular value decomposition based method has been developed and is used to align and calibrate the camera with the mask. The final step is estimating the system matrices of the lensless system. The system matrices enable the perfect reconstruction and a complete realization of a separable mask based lensless camera. A scheme for estimating the system matrices of the lensless imager using Hadamard basis is proposed and confirmed using simulations and the strategy for experimental verification is proposed. As far as we know, this is the first study that focuses on designing and developing a lensless camera in the visible light domain for use in picosatellites
Thermal energy storage in metal-organic framework materials for climate control of Martian buildings
No full textTo survive on the surface of a near atmosphere-less Mars, humans must be able to provide thermal energy to buildings to sustain temperature changes from -73°C to 20°C. The goal of the thesis is to create a passively-working thermal battery using materials currently available to humans; it must be the sole heat source to the Martian buildings. Metal-organic framework materials adsorb CO2 in a reversible exothermic chemical reaction, thereby providing heat to the buildings. A model was made in ABAQUS to simulate the adsorption mechanism; two parallel coupled simulations were run in a staggered approach, heat conduction and mass diffusion, to simulate chemical reaction. The model was then used, with the chosen materials, to simulate several geometry permutations of Martian buildings, the common denominator being the square area of the liveable space and walls. The material was able to provide a significant portion of the required heat and saved up to 97% power otherwise demanded from conventional energy sources.Aerospace Engineerin
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