879 research outputs found
Orthaga mangiferae Misra 1932
No full text34. Orthaga mangiferae Misra, 1932: 539 Type locality: India Distribution. Indian records: India (Misra 1932, Mathew 2006). Global records: unknown.Published as part of Singh, Navneet, Ranjan, Rahul, Talukdar, Avishek, Joshi, Rahul, Kirti, Jagbir Singh, Chandra, Kailash & Mally, Richard, 2022, A catalogue of Indian Pyraloidea (Lepidoptera), pp. 1-423 in Zootaxa 5197 (1) on page 51, DOI: 10.11646/zootaxa.5197.1.1, http://zenodo.org/record/725229
Arbitration and Dispute Settlement in Foreign Indirect Investment. The increasing significance and use of arbitration in international loan agreements, syndicated loans and international bond issues
No full textThis dissertation examines the suitability of arbitration for the resolution of securities regulatory claims and it adoption globally, which has resulted in international arbitration becoming the favoured dispute resolution mechanism in the securities industry. The author explains that disputes arising out of international bilateral and syndicated loan agreements are generally considered to be arbitrable, while international bond disputes are often derived from the controversies over the application of mandatory national laws and the compliance with securities regulation provisions - so the arbitrability of international bond disputes depends on the acceptance of the arbitrability of securities regulatory claims
A monolithically integrated power JFET and Junction Barrier Schottky diode in 4H silicon carbide
No full textEfficiency of power management circuits depends significantly on their constituent switches and rectifiers. The demands of technology are increasingly running up against the intrinsic properties of Si based power devices. 4H-Silicon Carbide (SiC) has superior properties that make it attractive for high power applications. SiC rectifiers are already a competitive choice and SiC switches have also been commercialized recently. Junction Barrier Schottky (JBS) diodes, which combine the advantages of PN and Schottky, have higher Figure of Merit (FOM) as rectifiers. Among switches, a robust and mature process has been developed for Silicon Carbide Vertical Junction Field Effect Transistors (VJFETs), which currently gives it the highest unipolar FOM. Switches are frequently combined with anti-parallel diodes in power circuits. This thesis describes the development of a SiC-based monolithically integrated power switch and diode. Monolithic integration increases reliability and efficiency, and reduces cost. Because of their superior properties and similarities in fabrication, we chose the SiC VJFET and JBS diode as the switch and rectifier. Detailed design, fabrication and characterization of the integrated switch to block above 800 V and conduct current beyond 100 A/cm2 is explained. In this process, the first physics-based 2-D compact model is developed for reverse leakage in a JBS diode as a function of design parameters. Since the gate-channel junctions of SiC VJFETs cannot be assumed to be abrupt, an existing analytical model for Si VJFETs is extended to account for graded gate-channel junctions. Using these analytical models, design rules are developed for the VJFET and JBS diode. Finite element simulations are used to find the best anode layout of the JBS diode and optimize electric field termination in the integrated device to ensure their capability to operate at high voltage. Finally, a spin-on glass based process is developed for filling the gate trenches of the VJFET to improve long-term robustness in extreme environments. The integrated power switch developed in this thesis points to the attractions of monolithic integration in SiC power circuits. Analytical compact design equations derived here will facilitate faster and easier design of switches and rectifiers for desired circuit operation.Ph. D.Includes bibliographical referencesIncludes vitaby Rahul Radhakrishna
Multi-scale approach for modeling stability, aggregation, and network formation of nanoparticles suspended in aqueous solutions
Full text linkSuspensions of nanoparticles (NPs) in aqueous solutions hold promise in many research fields, including energy applications, water desalination, and nanomedicine. The ability to tune NP interactions, and thereby to modulate the NP self-assembly process, holds the key to rationally synthesize NP suspensions. However, traditional models obtained by coupling the DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory of NP interactions, or suitable modifications of it, with the kinetic theory of colloidal aggregation are inadequate to precisely model NP self-assembly because they neglect hydration forces and discrete-size effects predominant at the nanoscale. By synergistically blending molecular dynamics and stochastic dynamics simulations with continuum theories, we develop a multi-scale (MS) model, which is able to accurately predict suspension stability, timescales for NP aggregation, and macroscopic properties (e.g., the thermal conductivity) of bare and surfactant-coated NP suspensions, in good agreement with the experimental data. Our results enable the formulation of design rules for engineering NP aqueous suspensions in a wide range of applications
Tube-based NMPC for Non-Holonomic Multi-agent System in Unknown Environments: Prelude to Modern Control
No full textThis thesis addresses the problem of controlling a fleet of agents sub ject to disturbances and input/state constraints, with a focus on ensur ing robustness to these disturbances. The control problem is defined for a set of agents operating in a shared workspace, where each agent must fol low a desired trajectory while avoid ing collisions and maintaining net work connectivity. A decentralized tube based Nonlinear Model Predic tive Control is developed (NMPC) to meet these objectives. Experi mental results demonstrate that the NMPC approach effectively follows desired trajectories and mitigates dis turbances. The leader and follower agents maintain low distance and ori entation errors. The control strategy successfully avoids obstacles, prevents inter-agent collisions, and maintains communication constraints.This thesis addresses the problem of controlling a fleet of agents sub ject to disturbances and input/state constraints, with a focus on ensur ing robustness to these disturbances. The control problem is defined for a set of agents operating in a shared workspace, where each agent must fol low a desired trajectory while avoid ing collisions and maintaining net work connectivity. A decentralized tube based Nonlinear Model Predic tive Control is developed (NMPC) to meet these objectives. Experi mental results demonstrate that the NMPC approach effectively follows desired trajectories and mitigates dis turbances. The leader and follower agents maintain low distance and ori entation errors. The control strategy successfully avoids obstacles, prevents inter-agent collisions, and maintains communication constraints
Performance investigations on modified vertical axis water turbine: Combination of lift and drag
No full textA micropower electrocardiogram amplifier
No full textWe introduce an electrocardiogram (EKG) preamplifier with a power consumption of 2.8 muW, 8.1 muV[subscript rms] input-referred noise, and a common-mode rejection ratio of 90 dB. Compared to previously reported work, this amplifier represents a significant reduction in power with little compromise in signal quality. The improvement in performance may be attributed to many optimizations throughout the design including the use of subthreshold transistor operation to improve noise efficiency, gain-setting capacitors versus resistors, half-rail operation wherever possible, optimal power allocations among amplifier blocks, and the sizing of devices to improve matching and reduce noise. We envision that the micropower amplifier can be used as part of a wireless EKG monitoring system powered by rectified radio-frequency energy or other forms of energy harvesting like body vibration and body heat.electrocardiogram (EKG
Development of a corrosion testing method for hydrophobic coatings under hydrostatic pressure
No full textSurface coatings used for corrosion prevention and inhibition are subjected to a wide range of dynamic mechanical and chemical conditions. Hydrophobic and superhydrophobic coatings are a class of coatings that have the unique ability to trap air at the interface between the coating and its environment, preventing the transport of corrosive media to the substrate. This is especially useful in submerged environments and in environments with high precipitation, where the composite layer of air can act as an additional barrier between the substrate and the environment. Instruments, cables, and connectors of commercial oceanographic equipment used for observation, sensing, and measurement fail at unacceptably high rates, and replacement or repair of these devices are prohibitively expensive. Similarly, corrosion is a general problem for offshore wind farms and oil and gas structures due to the high precipitation environments where they are used, leading to structural degradation and damage. The force at which liquid droplets impact a coated surface can significantly affect the protective properties of the coating. For superhydrophobic coatings, these two phenomena can cause severe disruption to the layer of air at the interface between the coating and environment, and this can have severely degrade the protective properties of the coating. Even though superhydrophobic coatings have been well-investigated for their ability to reduce the wettability of a surface and thereby inhibit corrosion, their behavior under varying hydrostatic pressures are not well-understood. This research work presents a method by which superhydrophobic coatings on steel substrates can be evaluated for corrosion inhibition while under hydrostatic pressure. Many hydrophobic and superhydrophobic coatings that have been recently developed are easily damaged either from simply touching the surface with bare skin or via an abrasive load. This research also addresses the impact that mechanical loads have on the protective properties of a commercial superhydrophobic coating to determine its industrial viability.Electrochemical impedance spectroscopy (EIS) was used to study the influence of hydrostatic pressure on the composite air layer and the corrosion inhibition properties of a commercially available superhydrophobic coating. To evaluate the impact that the air layer has on the protective properties, tests were performed on the coated surface in the presence and absence of the air layer. The air layer was removed by wetting the surface with ethanol before testing, which forced a transition from the Cassie wetting state into the Wenzel state. Equivalent circuits were applied to the EIS data to separate the contributions of the air layer to the corrosion inhibition properties of the coating. The results demonstrated that the superhydrophobic coating transitioned from the Cassie wetting state into the Wenzel state under hydrostatic pressure. The corrosion inhibition properties of the coating were found to drastically decrease with increasing hydrostatic pressures. The impact of mechanical abrasion of the superhydrophobic coating was evaluated to understand the tribological impact. The coated samples were subjected to increasing abrasive loads and the surface, wetting, and corrosion inhibition properties were evaluated. The surface roughness was found to decrease with increasing abrasive loads, which then resulted in a decrease in contact angles, an increase in sliding angles, and increased corrosion rates.From these studies, a method has been established to study and quantify the influence that hydrostatic pressures and abrasive loads have on the corrosion inhibition abilities of a superhydrophobic coating
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