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    Microstructures and mechanical properties of ternary Ti-Si-Sn alloys

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    Titanium based alloys are one of the important structural materials with applications ranging from aerospace to biomedical industries. Several ternary Ti-Si-Sn alloys were explored in this study to design the microstructure comprising of binary and ternary eutectics corresponding to Ti-Si, Ti-Sn and Ti-Si-Sn system. The microstructural evolution in these alloys was studied using a combination of characterization techniques and thermodynamic calculations. The predicted solidification path from thermodynamic calculations well supported the experimental microstructural data. In addition, mechanical property and microstructure relationship were determined by performing hardness measurements and evaluating stress-strain curves under compression

    An improved tunnel field-effect transistor with an L-shaped gate and channel

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    An improved tunnel field-effect transistor with an L-shaped gate and channel (LLTFET) is proposed herein. The new structure shows an increased ON-current without any change in the overall area in comparison with state-of-the-art structures. The L-shaped gate extends into the substrate and overlaps with part of the source. An N+ pocket located just below the gate facilities tunneling in both the horizontal and vertical directions, which results in the increased ON-current. Three different models are proposed herein to increase the ON-current with the added advantage of simplified fabrication steps. For one of the proposed models, the ON-current is improved by 63 while the OFF-current is reduced to 12.5 compared with an L-shaped gate TFET (LGTFET) described in literature. An optimum model is also proposed, achieving a subthreshold swing of 21.2Â mV/decade at 0.05Vgs. The simulations are performed using Silvaco ATLAS with the nonlocal band to band tunneling (BTBT) model

    Site Response Study and Amplification Factor for Shallow Bedrock Sites

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    Amplification is a key paramter considered to account modifcation of seimic wave in the soil for earthquake resistance design of structure placed on soil. Initially, earthquake wave amplifications are related with shear wave velocity (Vs) ratio of soil and foundation layer, and then it was related to average value of Vs up to 30 m (Vs 30). Application of Vs 30 concept to represent amplification in shallow bedrock sites is questionable and has rock velocity added to soil velocity. In this study, shallow bedrock sites in Bengaluru, Chennai, Coimbatore and Vishakhapatnam has been analyzed to understand amplifications and its proximity to Vs 30. The site response calculations are done using one-dimensional nonlinear approach. Intraplate recordings from around the world suitable for the study area are selected. For comparison with known data, the amplification factors are evaluated considering the period ranges similar to international codes. Then, considering spectral signatures from response spectra for all site rock and surface motions, the factors are calculated for period range 0.01�0.06 s and 0.05�1.0 s. Based on the study, only one mid-period amplification factor has been proposed. This amplification factor represents the significant amplification of the site. Acceleration spectra show similar trends for different site classes irrespective of the fact that profiles are selected based on Vs values or SPT-N values. This is observed over a wide range of results and indicates shear modulus as an influencing parameter. Comparison of spectral signatures for different site classes suggests that amplification reduces as the modulus of the soil column increases. Thus, it may be appropriate to classify sites based on shear modulus of soil column

    Hybrid Microgrids for Diesel Consumption Reduction in Remote Military Bases of India

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    Grid connection is often not available at remote locations. As a result, diesel generators are commonly used in Indian remote military bases to generate electricity locally. Transportation of diesel to these remote locations is often difficult and expensive task. Communication and surveillance equipments along with border fences and illumination need reliable electricity supply. Any disruption in diesel supply can severely impact the operation of the military base. Fuel transportation routes are often cut off during extreme weather conditions. In addition, diesel generators are prone to failure and cause significant air pollutions. Renewable energy sources are often available at these remote locations. These renewable energy sources can be used to substitute the diesel based generation partially. In this paper, hybrid microgrids consisting of both renewable and diesel generators are proposed for remote military bases. Use of local renewable sources reduces the dependence on external diesel supply. In addition, the consumption of diesel is reduced due to the use of renewable energy sources. Detailed Cost Benefit analysis has been done to show the effectiveness of the hybrid microgrid. It is shown that this hybrid microgrid can be a possible solution for reduction of diesel consumption in remote military bases of India

    Robust emergence of sharply tuned place-cell responses in hippocampal neurons with structural and biophysical heterogeneities

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    Hippocampal pyramidal neurons sustain propagation of fast electrical signals and are electrotonically non-compact structures exhibiting cell-to-cell variability in their complex dendritic arborization. In this study, we demonstrate that sharp place-field tuning and several somatodendritic functional maps concomitantly emerge despite the presence of geometrical heterogeneities in these neurons. We establish this employing an unbiased stochastic search strategy involving thousands of models that spanned several morphologies and distinct profiles of dispersed synaptic localization and channel expression. Mechanistically, employing virtual knockout models (VKMs), we explored the impact of bidirectional modulation in dendritic spike prevalence on place-field tuning sharpness. Consistent with the prior literature, we found that across all morphologies, virtual knockout of either dendritic fast sodium channels or N-methyl-d-aspartate receptors led to a reduction in dendritic spike prevalence, whereas A-type potassium channel knockouts resulted in a non-specific increase in dendritic spike prevalence. However, place-field tuning sharpness was critically impaired in all three sets of VKMs, demonstrating that sharpness in feature tuning is maintained by an intricate balance between mechanisms that promote and those that prevent dendritic spike initiation. From the functional standpoint of the emergence of sharp feature tuning and intrinsic functional maps, within this framework, geometric variability was compensated by a combination of synaptic democracy, the ability of randomly dispersed synapses to yield sharp tuning through dendritic spike initiation, and ion-channel degeneracy. Our results suggest electrotonically non-compact neurons to be endowed with several degrees of freedom, encompassing channel expression, synaptic localization and morphological microstructure, in achieving sharp feature encoding and excitability homeostasis

    Strong Converse Using Change of Measure Arguments

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    The strong converse for a coding theorem shows that the optimal asymptotic rate possible with vanishing error cannot be improved by allowing a fixed error. Building on a method introduced by Gu and Effros for centralized coding problems, we develop a general and simple recipe for proving strong converse that is applicable for distributed problems as well. Heuristically, our proof of strong converse mimics the standard steps for proving a weak converse, except that we apply those steps to a modified distribution obtained by conditioning the original distribution on the event that no error occurs. A key component of our recipe is the replacement of the hard Markov constraints implied by the distributed nature of the problem with a soft information cost using a variational formula introduced by Oohama. We illustrate our method by providing a short proof of the strong converse for the Wyner-Ziv problem and strong converse theorems for interactive function computation, common randomness and secret key agreement, and the wiretap channel; the latter three strong converse problems were open prior to this work

    Investigation of Recessed Junctionless Double Gate MOSFET for Radio Frequency Applications

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    Junctionless Metal Oxide Semiconductor Field-Effect Transistor (JL MOSFET) is one of the promising candidate to replace the junction based MOSFET for upcoming technology nodes. Semiconductor industries are continuously urging for large ON current with the low OFF current and low specific on resistance. However, high ON current is achieved in Conventional (Conv.) JL DG MOSFET by using high doping concentration at the cost of high OFF current which leads depletion mode operation. Moreover, low doping, narrow channel thickness and high work function gate materials are using to operate Conv. JL DG MOSFET in enhancement mode (Vth > 0Â V for N-JL DG MOSFET, Vth < 0Â V for P-JL DG MOSFET) but ON current is reduced in all above mentioned solutions. To overcome the above mentioned problems, a new architecture is developed called Recessed JL DG MOSFET. In Recessed JL DG MOSFET silicon region is recessed under the gate region and some gate portion is extended towards source and drain region. Recessed JL DG MOSFET shows the same ON current as achieved in Conv. JL DG MOSFET with very low OFF current (leakage current) by considering high doping concentration. Surface potential, electron density, energy band distribution, drain current have been investigated to proof the enhancement mode operation of Recessed JL DG MOSFET. Figure of Merits (FOMs) for RF performance such as Trans-conductance, capacitance and intrinsic power gain (S21), Trans-conductance frequency product (TFP), Gain frequency product (GFP) and Gain trans-conductance frequency product (GTFP) have also investigated of Recessed JL DG MOSFET

    Electric current driven formation of micro-and nano-sized beads in thin Cr films

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    Nano films of chromium with thicknesses from 20 to 200 nm were deposited on silicon substrates and were treated by electric current induced by AFM tip in ambient atmosphere. The melting on the nanoscale, electric current induced migration of the material and chemical reaction of oxidization of chromium were revealed in melting craters around the point of application of the current by optical and electronic scanning microscopy, AFM, and Raman spectroscopy. The flow of the material induced by electric current is accompanied by formation and motion of the matrix of the spherical nanoparticles (beads) in the crater of melt on its periphery. The reaction of chromium oxidation and surface tension of the melted material on the silicon substrate are expected to be responsible for the matrix of nano beads formation under comparatively small currents. Raman spectroscopy confirms that in the vicinity of the periphery of the melted craters around AFM tip application, the beads of oxide phase Cr2O5 are present

    Phase inconsistency as a major source of error in NGFS forecast

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    South Asian monsoon exhibits multiscale spatiotemporal variability. Analyzing the nature and behavior of numerical weather forecast error associated with these space-time heterogeneities will eventually help in improving the models. We investigate the spatiotemporal error characteristics of the National Centre for Medium-Range Weather Forecasting (NCMRWF) Global Forecast System (NGFS) model over South Asian land and ocean separately. Although error grows with lead-time, it saturates within 3�5 days of forecast initiation. The saturated error is only about 15�25 higher than that of day-1, indicating that most of the error accumulates within first 24-h of forecast. Increase in error over oceanic regions is due to an increase in the area with high error at all precipitation ranges with large day-to-day variability. However, over land error growth is primarily confined at locations of high mean precipitation. Decomposition of error arising due to intensity and phase variations reveals that about 90 of it arises from the model�s inability to capture phase of precipitation at various timescales. We show that NGFS cannot capture synoptic scale variations (< 10 day) after day-2. Both the high-frequency (10�20 day) and low-frequency (30�60 day) intraseasonal variations are reasonably predicted up to day-3. At diurnal timescale, NGFS forecasts show a peak in precipitation about 3�6 h prior to that observed, both over land and ocean. Surprisingly, this error does not change with lead-time. Lastly, we show that major error characteristics do not depend on the seasonal mean monsoon rainfall

    Quantum channels over graph states using generalized measurement-based quantum computation framework

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    Measurement-based quantum computation (MBQC) is an alternative way of quantum information processing that describes the unitary evolution of a quantum state using the cluster state and well-defined sequential measurements. We give a closed form expression for the unitary evolution that a state goes through in terms of the network parameters and measurement outcomes on various qubits of the network. We extend the framework of MBQC to describe quantum channels. Using the new framework, we define a valid quantum unital channel between any two nodes of a graph consisting of nodes connected by edges. We describe the channel in terms of the network parameters and initial state. Our generalization consists of modifying the unitary operation, measurement operators, initial arbitrary state of the qubits at all the nodes of the network. We also study the inverse problem of devising an appropriate approximate unitary in the generalized MBQC to create any given quantum channel

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