Restoration of Equalization and Aeration Tanks of Effluent Treatment Plant at the Mysugar Factory, Mandya, Karnataka, India

This paper deals with the restoration measures resorted to strengthen the structure and prevent the leakage of the equalization and aeration tanks of effluent treatment plant in a sugar factory. These tanks showed distress at the hydraulic test itself before commissioning due to the failure of the reinforced concrete floor and bund lining on account of loss of support due to excessive deformation of the substratum. Extensive sand piling was resorted to strengthen the substratum before recasting the reinforced concrete floor and bund lining to ensure structural stability and prevent leakage. These tanks are functioning satisfactorily since two years after restoration serving the intended functions of the eflluent treatment

Doping Dependence of Thermal Oxidation on n-type 4H-SiC

The doping dependence of dry thermal oxidation rates in n-type 4H-SiC was investigated. The oxidation was performed in the temperature range 1000C to 1200C for samples with nitrogen doping in the range of 6.5e15/cm3 to 9.3e18/cm3, showing a clear doping dependence. Samples with higher doping concentrations displayed higher oxidation rates. The results were interpreted using a modified Deal-Grove model. Linear and parabolic rate constants and activation energies were extracted. Increasing nitrogen led to an increase in linear rate constant pre-exponential factor from 10-6m/s to 10-2m/s and the parabolic rate constant pre-exponential factor from 10e9m2/s to 10e6m2/s. The increase in linear rate constant was attributed to defects from doping-induced lattice mismatch, which tend to be more reactive than bulk crystal regions. The increase in the diffusion-limited parabolic rate constant was attributed to degradation in oxide quality originating from the doping-induced lattice mismatch. This degradation was confirmed by the observation of a decrease in optical density of the grown oxide films from 1.4 to 1.24. The linear activation energy varied from 1.6eV to 2.8eV, while the parabolic activation energy varied from 2.7eV to 3.3eV, increasing with doping concentration. These increased activation energies were attributed to higher nitrogen content, leading to an increase in effective bond energy stemming from the difference in C-Si (2.82eV) and Si-N (4.26eV) binding energies. This work provides crucial information in the engineering of SiO2 dielectrics for SiC MOS structures, which typically involve regions of very different doping concentrations, and suggests that thermal oxidation at high doping concentrations in SiC may be defect mediated.Comment: 13 pages. 9 figures, accepted as a transiction in IEEE electron device. TED MS#8035

Structural and Electrical Characterization of Porous Silicon Carbide Formed in n-6H-SiC Substrates

Investigation of porous silicon carbide layer morphology and its growth rate was studied along with electrical characterization. Morphology of the formed porous SiC layers was analyzed by scanning electron microscopy. The effective carrier density in porous layers was extracted from the capacitance-voltage characteristics of mercury probe Schottky contacts to the porous layer. It was found that the effective carrier density in porous layer and the pore density are in good correlation. The wide bandgap of silicon carbide ͑SiC͒ semiconductor gives it the edge over other materials for making high power, high temperature, and high frequency devices. High thermal conductivity, saturation electric drift velocity, and breakdown electric field adds to its better thermal and electronic properties. In the last few years it has been recognized that nanostructured porous semiconductor networks show interesting optoelectrical properties different from those of bulk semiconductors. These properties are related to the presence of a three-dimensional ͑3-D͒ interfacial structure with a huge internal surface area and huge volume density of surface-localized electrons. At present, extensive research is devoted to nanostructured semiconductor networks. It is believed that such networks will play an important role in future ͑opto-͒ electronic devices ͑solar cells, light emitting diodes, chemical sensors, electrochromic devices, single electron transistors͒. In recent years, porous silicon carbide has been of interest due to its more efficient luminescence compared to bulk SiC. 1 Also, electroluminescent and gas sensor devices based on porous SiC have been demonstrated. 2,3 In order to use porous SiC in device application, the correlation between electrical characteristics and structural morphology of the porous layer must be understood. The goal of this work was to investigate the surface and pore morphology of 6H-SiC with respect to the effect of varying current density used during electrochemical anodization. The characterization technique used to study the surface and pore morphology has never been reported before. Preparation and Characterization Porous silicon carbide ͑por-SiC͒ samples were prepared using n-6H-SiC (0°8Ј off axis͒ wafers from CREE Research Inc. This wafer was nitrogen doped and had a resistivity of 0.174 ⍀ cm. Photo-assisted electrochemical etching was performed on both the polished silicon-and carbon-terminated faces of the samples using a 150 W mercury ͑Hg͒ lamp and a mixture of hydrofluoric acid ͑HF͒ ͑1͒: ethanol ͑1͒ as electrolyte for a time period of 2-60 min. Prior to turning on the current, the sample arrangement in the Teflon cell was kept under the Hg lamp for 1 min. The counter electrode was a platinum wire positioned about 1 cm from the sample. The applied current density was between 10 and 80 mA/cm 2 . Por-SiC samples were analyzed after ultrasonic cleaning in methanol for 10-20 min. Thicknesses of the porous layers were measured by the cylindrical grove technique. In order to study the porous structure beneath the surface, some samples were subjected to dry etching by reactive ion etching ͑RIE͒ to remove a thin ͑0.1-0.3 m͒ surface layer. The RIE was performed in the March Instrument, Inc. system using a gas mixture (CF 4 ϩ 15%O 2 ) at 150 W. A scanning electron microscope ͑SEM͒ was used to study the microstructure of the porous SiC surface layer. In this work we have taken two batches of five samples each, and we are showing the recurring results for SEM images. For the plots, average results of both the experiments are considered. Results and Discussion 5 This explains the formation of thinner porous layer on the Si face compared to the C face at the same conditions. The anodization rate appeared to be directly related to the current density used in these experiments. For the initial period ͑up to 10 min͒, the growth rate increases from 0.3 to 1.1 m/min for the Si face and from 0.8 to 1.5 m/min for the C face when the current

Microstructural and Mechanical Properties of Al2O3 and Al2O3/TiB2 Ceramics Consolidated by Plasma Pressure Compaction

Alumina oxide ceramics were produced by plasma pressure compaction (P2C) sintering process. Two types of pure α-alumina (Al2O3) and a mixture of alumina and titanium diboride (TiB2) powders were used as starting materials. Microstructure and mechanical properties, namely hardness, elastic modulus, and fracture toughness, were analyzed and correlated to the type of the sintered powders and the adopted manufacturing route. The microstructural development and the chemical composition variation induced by the sintering process were assessed by using scanning electron microscopy and x-ray diffraction. Nano-indentation and Chevron notch beam techniques were adopted to estimate the mechanical properties of the sintered ceramics. The conducted analyses show the capability of P2C technique to produce sound alumina ceramics. Pure alumina bulks exhibit a good level of compaction and mechanical properties close to those achievable with conventional sintering processes, such as hot isostatic pressing or spark plasma sintering. No significant alterations in the chemical composition of the ceramics were observed. The addition of the titanium diboride in the alumina powders caused a moderate increase in the grain size lowering the hardness and Young’s modulus of the sintered alumina and, at the same time, increased its fracture toughness to the occurrence of toughening mechanisms, like crack bridging and crack deflection

Lorentz transformations that entangle spins and entangle momenta

Simple examples are presented of Lorentz transformations that entangle the spins and momenta of two particles with positive mass and spin 1/2. They apply to indistinguishable particles, produce maximal entanglement from finite Lorentz transformations of states for finite momenta, and describe entanglement of spins produced together with entanglement of momenta. From the entanglements considered, no sum of entanglements is found to be unchanged.Comment: 5 Pages, 2 Figures, One new paragraph and reference adde

Complex Energy Spectrum and Time Evolution of QBIC States in a Two-Channel Quantum wire with an Adatom Impurity

We provide detailed analysis of the complex energy eigenvalue spectrum for a two-channel quantum wire with an attached adatom impurity. The study is based on our previous work [Phys. Rev. Lett. 99, 210404 (2007)], in which we presented the quasi-bound states in continuum (or QBIC states). These are resonant states with very long lifetimes that form as a result of two overlapping continuous energy bands one of which, at least, has a divergent van Hove singularity at the band edge. We provide analysis of the full energy spectrum for all solutions, including the QBIC states, and obtain an expansion for the complex eigenvalue of the QBIC state. We show that it has a small decay rate of the order $g^6$, where $g$ is the coupling constant. As a result of this expansion, we find that this state is a non-analytic effect resulting from the van Hove singularity; it cannot be predicted from the ordinary perturbation analysis that relies on Fermi's golden rule. We will also numerically demonstrate the time evolution of the QBIC state using the effective potential method in order to show the stability of the QBIC wave function in comparison with that of the other eigenstates.Comment: Around 20 pages, 50 total figure

Unital quantum operators on the Bloch ball and Bloch region

For one qubit systems, we present a short, elementary argument characterizing unital quantum operators in terms of their action on Bloch vectors. We then show how our approach generalizes to multi-qubit systems, obtaining inequalities that govern when a ``diagonal'' superoperator on the Bloch region is a quantum operator. These inequalities are the n-qubit analogue of the Algoet-Fujiwara conditions. Our work is facilitated by an analysis of operator-sum decompositions in which negative summands are allowed.Comment: Revised and corrected, to appear in Physical Review

AFMB-Net: DeepFake Detection Network Using Heart Rate Analysis

With advances in deepfake generating technology, it is getting increasingly difficult to detect deepfakes. Deepfakes can be used for many malpractices such as blackmail, politics, social media, etc. These can lead to widespread misinformation and can be harmful to an individual or an institution’s reputation. It has become important to be able to identify deepfakes effectively, while there exist many machine learning techniques to identify them, these methods are not able to cope up with the rapidly improving GAN technology which is used to generate deepfakes. Our project aims to identify deepfakes successfully using machine learning along with Heart Rate Analysis. The heart rate identified by our model is unique to each individual and cannot be spoofed or imitated by a GAN and is thus susceptible to improving GAN technology. To solve the deepfake detection problem we employ various machine learning models along with heart rate analysis to detect deepfakes