Self-consistent solution of two-dimensional poisson and Schrödinger wave equations for nanoscale MOSFET approaching ballistic limit

A numerical solution of the potential distribution of two-dimensional Poisson equation and Schr?dinger wave equation under a set of boundary conditions has been obtained for a deep submicron and nanoscale MOSFET. The output characteristics can be found out by simply solving the two-dimensional Poisson equation under specific boundary conditions governed by the physics of the device. The channel potential profile has been presented. It is seen that the classical model underestimates the channel voltage and hence the longitudinal electric field in the channel as compared to that obtained through the quantum mechanical approach. For the purpose of validation, the results obtained on the basis of our model have been compared and contrasted with reported experimental result.     

Theoretical calculation of hydrogen desorption energies of calcium hydride clusters

Recently calcium hydride has attracted attention as a possible component in ternary complex hydrides such as Ca(AlH₄)₂, Ca₂SiH_x and quaternary complex hydrides of the type Li–B–Ca–H. Although in bulk form CaH₂ decomposes reversibly above 600° centigrade we were motivated to see whether calcium hydride in cluster form has properties suitable for hydrogen storage. We report here the results of DFT calculations using VASP^® package for clusters Ca_nH_2n with n = 1, 2, 3, 4, 6, 8, 10, 12, 14, 16, 20 to get the ground state geometries, energies, bond lengths, and desorption energies, after molecular dynamics optimization. The desorption energy vs. cluster size n curve showed that the desorption energy goes up sharply to ∼1.4 eV per H₂ for n up to 4, followed by a broad maximum of ∼1.8 eV per H₂ around n = 12–14, and then tapers off to a nearly constant value of 1.6 eV per H₂ approximating bulk behavior, which compares favorably with previously reported results. Comparison of these results with those of Mg_nH_2n shows that Ca_nH_2n has a lesser potential as a hydrogen storage medium.     

Enhanced microwave processing of epoxy nanocomposites using carbon black powders

The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the knowledge of dielectric properties of the test specimen is required in order to understand the extent of curing using microwaves. In this study, a detailed investigation is carried out by considering a number of carbon black (CB) samples having particulate sizes in the range of 15–65 nm. The dielectric properties of the synthesized CB/epoxy nanocomposites, before and after microwave curing, are measured using the advanced cavity perturbation method (CPM). It is observed that the CB/epoxy nanocomposite having smallest particulate size i.e., 15 nm attains the maximum value of dielectric constant (ε_r′) and loss tangent (tan δ) of 10.79 and 0.05, respectively. These results indicate that the epoxy reinforced with the CB having least particulate size would interact more effectively with microwaves, which are confirmed by the experimental data showing that the nanocomposite with smallest CB particle size of 15 nm requires the minimum curing time. The dielectric properties especially the loss factors of fully cured samples are found to decrease after curing indicating that the dielectric properties of post cured samples can provide an idea about the extent of curing. At last, thermal, mechanical and morphological analyses are also performed on all the microwave cured epoxy samples.     

Generative model based robotic grasp pose prediction with limited dataset

Applied Intelligence - In the present investigation, we propose an architecture which we name as Generative Inception Neural Network (GI-NNet), capable of predicting antipodal robotic grasps...     

Planning and Design of Cost-effective Water Harvesting Structures for Efficient Utilization of Scarce Water Resources in Semi-arid Regions of Rajasthan,India

Water-harvesting structures have the potential to increase the productivity of arable lands by enhancing crop yields and by reducingthe risk of crop failure in arid and semi-arid regions, where water shortages are common because of scanty rainfall and its uneven distribution. In semi-arid regions of Rajasthan, India, existing practice of harvesting rainwater is through anicut and earthen embankments. Because of higher costs and higher technical skills involved in the construction of these structures, these structures have not been accepted by the resource-poor local people. Therefore, in the present paper, the detailed design of some low-cost water-harvesting structures using locally available materials and adaptable to the socio-economic conditions of the beneficiaries is discussed. Two types of cost-effective water-harvesting structures, which include dry stone masonry and upstream-wall cement masonry of heights 1, 2, and 2.5 m for catchments of less than 10, 10 to 20, and 20 to 30 ha, respectively are proposed and designed. The analysis of costs involved in constructing dry stone masonry and upstream-wall cement masonry water-harvesting structures, emergency spillway, anicuts and earthen embankments revealed that the earthen embankments have the least cost of construction whereas the anicuts have the highest construction costs for all the selected heights. However, based on the past experiences, earthen embankments are not suitable for the semi-arid regions of Rajasthan. The economic evaluation of the proposed structures indicated that the dry stone masonry structures are very cost-effective for the region with a benefit-cost ratio of 3.5:1 and the net present worth value of Rs. 102978. Although the economic indicators ranked the upstream-wall cement masonry structures lower than the dry stone masonry structures, the former has greater stability and strength compared to the latter. In practice, both the cost-effective water-harvesting structures (i.e., dry stone masonry and upstream-wall cement masonry) are gaining wide acceptance and popularity in the region through some nongovernmental organizations, which have adopted the design presented in this paper.     

Effect of compression ratio on performance,emission and combustion characteristics of diesel–acetylene-fuelled single-cylinder stationary CI engine

The present investigation aims to depict the effect of compression ratio on performance, emission and combustion characteristics of diesel–acetylene-fuelled stationary compression ignition engine. The optimum values for compression ratio, injection timing and injection pressure for diesel were experimentally found, and baseline data were established as 20, 23° before top dead centre and 210 bar, respectively. In order to investigate the effect of acetylene fuelling, acetylene gas was inducted at four different flow rates of 60, 120, 180 and 240 litres per hour at compression ratio 20. It was observed that the flow rate of 120 litres per hour gave the best performance with highest brake thermal efficiency of 25.09%. In order to find the optimum compression ratio for acetylene fuelling at 120 litres per hour, experimentation was done at different compression ratios of 18, 19, 20, 21 and 22. Experimental results showed that highest brake thermal efficiency of 25.72% was achieved at compression ratio 21 for diesel–acetylene fuelling which was much higher than 23.32% for pure diesel. Carbon monoxide, hydrocarbon and smoke emissions were also measured and found to be lower, while the NOx emissions were higher at optimized values in dual-fuel mode as compared to those for pure diesel. Peak cylinder pressure and net heat release rate were also calculated and found to be higher in dual-fuel mode compared to diesel mode.     

Synthesis of nano-TiC powder using titanium gel precursor and carbon particles

The paper presents a novel process for synthesis of nano-size titanium carbide by reaction between titanium bearing precursor gel and nano carbon particles derived from soot at different temperatures in the range of 1300-1580 °C for 2 h under argon cover. The HRTEM studies of TiC powder synthesized by heating at 1580 °C show the presence of cube shaped particles (~ 60-140 nm) and hollow rods (diameter ~ 30-185 nm). The average particle size of crystallites, calculated by Scherer equation is observed to be ~ 35 nm while the surface area-density measurements indicate it to be ~ 113 nm. The surface area decreases with increase in reaction temperature.