Impact of nano sized SiC and Gr on mechanical properties of aerospace grade Al7075 composites

Aluminum composites exhibit high resistance to wear and corrosion, possess high strength, offer durability and more such properties. In this study, Al7075, reinforced with nano size SiC - Gr was produced by a stir casting technique and its microstructure and mechanical behavior were evaluated. Reinforcements were added in the range of 0 - 3 wt. %. The microstructure study, tensile and compression strength of the developed hybrid Metal Matrix Composites have been analyzed and examined. From the investigational study, it was found that the reinforcements are evenly dispersed in the base material. The porosity and density of the developed composites were found to be enhanced. The mechanical properties such as ultimate tensile and compressive strength of the developed MMCs could be improved by addition of SiC particulates compared to base material. Further, the strength of developed hybrid composites was found to be decreased by adding of solid lubricant such as graphite (Gr) particulates along with hard ceramic particulates. Finally, fractured surface of the tensile test specimens were analysed using a SEM analysis

Assessment of physiochemical and microbial concentrations in different fresh waters in Tiruchirappalli city: A special emphasize on their correlation

The six fresh water samples belonging to three different sources (Cauvery river water, ground water and bottle drinking water) from Tiruchirappalli city were collected (bi-monthly sampling) during April 2014 to June 2014 for physiochemical and microbiological study. Bacterial and physiochemical parameters levels were two to ten folds higher in river water sample than in ground and bottle water due to discharges of municipal sewage and human activities. The elevated bacterial communities in May month indicated that which received waste materials from landside and more visits due to the lack of water scarcity. The higher pollution index (PI) ratio (>1) were observed in river water samples (than the ground and bottle water) in all the three months indicate the human fecal matters were responsible for water pollution. The order of decreasing microbial and physiochemical values were: May month > April month > June month. The correlation proved that physicochemical parameters were strongly supported to microbial communities due to addition of rich organic content in the water bodies from different pollution sources. Based on the report, this study was suggesting that throughout impoundment is needed to protect fresh water sources

Impact of Organized Retailing on the Informal Retailing of Select Organizations in Bangalore

The Retail sectors have become one of the most dynamic growing sectors in recent times. Retailing has always been an integral part of economic development. Nations with strong retail activity have enjoyed greater economic and social progress. It contributes to the development by matching the individual requirements of the population with the producers and suppliers of merchandise. This study focuses on the growth & development of retail sector. And business practices adopted by Retailing and its impact on informal organizations. This research paper is analytical and empirical in nature. Findings of the study is the highest Pearson correlation value is between ‘Ethical practices’ and ‘Overall Importance Factors in Retail’ and the lowest Pearson correlation value is between ‘Price’ and ‘Overall Importance Factors in Retail

Multilevel governance challenges in transitioning towards a national approach for REDD+:Evidence from 23 subnational REDD+ initiatives

Although REDD+ was conceived as a national approach to reducing emissions from deforestation and forest degradation, many of the early advances have been at the subnational level. It is critical to link these subnational efforts to emerging national REDD+ frameworks, including with respect to finance and benefit distribution, setting reference levels, measurement, reporting and verification (MRV), land policy and safeguards. We use evidence from interviews with proponents from 23 subnational REDD+ initiatives in six countries to characterize the multilevel governance challenges for REDD+. We analyse the differences in perceived challenges between subnational jurisdictional programs and project-based initiatives, and then analyse proponents’ perceptions of the relationship between government policies at multiple levels and these REDD+ initiatives. We find important multilevel governance challenges related to vertical coordination and information sharing and horizontal and inter-sectoral tensions, as well as concerns over accountability, equity and justice. Though the shift to a nested, jurisdictional or national REDD+ is sometimes approached as a technical design issue, this must be accompanied by an understanding of the interests and power relations among actors at different levels. We outline challenges and suggest priority areas for future research and policy, as countries move towards a national REDD+ system

Refined Hybrid Microgrid Architecture for the Improvement of Voltage Profile

Hybrid microgrid is emerging as a flexible and modular solution that integrates various heterogeneous energy resources and loads. This conventional hybrid microgrid architecture can also reduce the number of power conversion stages, when compared to other architectures of microgrid such as, centralized DC bus and centralized AC bus architectures. But, these conventional hybrid microgrid architectures are having poor fault tolerant capacity that leads to severe power imbalances in the microgrid system. With this aspect, this paper propose the refined hybrid microgrid architecture that can handle system uncertainties and improves the voltage profile. The proposed refined hybrid microgrid architecture consists of two layers (AC layer and DC layer) through which each and every constituent of the microgrid is connected. This provides continuity in power supply to the microgrid loads via the possibility of bi-directional power flow between AC layer and DC layer. The proposed architecture is simulated using MATLAB/Simulink®. From the results, it is observed that, this proposed refined hybrid microgrid architecture improves the voltage profile of the system during faults

Stable and Metastable vortex states and the first order transition across the peak effect region in weakly pinned 2H-NbSe_2

The peak effect in weakly pinned superconductors is accompanied by metastable vortex states. Each metastable vortex configuration is characterized by a different critical current density J_c, which mainly depends on the past thermomagnetic history of the superconductor. A recent model [G. Ravikumar, et al, Phys. Rev. B 61, R6479 (2000)] proposed to explain the history dependent J_c postulates a stable state of vortex lattice with a critical current density J_c^{st}, determined uniquely by the field and temperature. In this paper, we present evidence for the existence of the stable state of the vortex lattice in the peak effect region of 2H-NbSe_2. It is shown that this stable state can be reached from any metastable vortex state by cycling the applied field by a small amplitude. The minor magnetization loops obtained by repeated field cycling allow us to determine the pinning and "equilibrium" properties of the stable state of the vortex lattice at a given field and temperature unambiguously. The data imply the occurence of a first order phase transition from an ordered phase to a disordered vortex phase across the peak effect.Comment: 20 pages, 10 figures. Corresponding author: S. Ramakrishna

Bidirectional ConvLSTMXNet for Brain Tumor Segmentation of MR Images

In recent years, deep learning based networks have achieved good performance in brain tumour segmentation of MR Image. Among the existing networks, U-Net has been successfully applied. In this paper, it is propose deep-learning based Bidirectional Convolutional LSTM XNet (BConvLSTMXNet) for segmentation of brain tumor and using GoogLeNet classify tumor & non-tumor. Evaluated on BRATS-2019 data-set and the results are obtained for classification of tumor and non-tumor with Accuracy: 0.91, Precision: 0.95, Recall: 1.00 & F1-Score: 0.92. Similarly for segmentation of brain tumor obtained Accuracy: 0.99, Specificity: 0.98, Sensitivity: 0.91, Precision: 0.91 & F1-Score: 0.88

Minimum and maximum against k lies

A neat 1972 result of Pohl asserts that [3n/2]-2 comparisons are sufficient, and also necessary in the worst case, for finding both the minimum and the maximum of an n-element totally ordered set. The set is accessed via an oracle for pairwise comparisons. More recently, the problem has been studied in the context of the Renyi-Ulam liar games, where the oracle may give up to k false answers. For large k, an upper bound due to Aigner shows that (k+O(\sqrt{k}))n comparisons suffice. We improve on this by providing an algorithm with at most (k+1+C)n+O(k^3) comparisons for some constant C. The known lower bounds are of the form (k+1+c_k)n-D, for some constant D, where c_0=0.5, c_1=23/32=0.71875, and c_k=\Omega(2^{-5k/4}) as k goes to infinity.Comment: 11 pages, 3 figure