CFD and Statistical Approach for Optimization of Operating Parameters in a Tangential Cyclone Heat Exchanger

Present work optimizes the operational parameters such as solid particle diameter, inlet air velocity and inlet air temperature on heat transfer rate by Taguchi method. Operational parameters play an important role in the performance of cyclone heat exchanger thus the parameter optimization is deemed important. The parameters have been analyzed under varying solid particle diameter (300 and 400 µm), inlet air temperature (323, 373, 423 and 473 K) and inlet air velocity (5, 10, 15 and 20 m/s). Results of heat transfer rate by varying the operational parameters have been found from Computational Fluid Dynamics (CFD) software Ansys Fluent. Orthogonal array of Taguchi, the signal-to-noise ratio and analysis of variance have been employed to found the optimal parameter values and the effect of parameters on heat transfer rate. Mixed level factor and L32 array is chosen for the design of analysis in Taguchi. Result of statistical analysis shows that the developed approach yields worthy results when comparing with predicted simulation values with confidence level of 99.5%. Taguchi analysis reveals that optimized levels of parameters are 300 µm, 473 K & 20 m/s for solid particles diameter, inlet air temperature and inlet air velocity respectively. Confirmation test was conducted in simulation and experiment for optimized parameters and result shows that maximum heat transfer rate was obtained with optimized parameter among the chosen operational parameters

Methionine biosynthesis and transport are functionally redundant for the growth and virulence of Salmonella Typhimurium

Methionine (Met) is an amino acid essential for many important cellular and biosynthetic functions, including the initiation of protein synthesis and S-adenosylmethionine-mediated methylation of proteins, RNA, and DNA. The de novo biosynthetic pathway of Met is well conserved across prokaryotes but absent from vertebrates, making it a plausible antimicrobial target. Using a systematic approach, we examined the essentiality of de novo methionine biosynthesis in Salmonella enterica serovar Typhimurium, a bacterial pathogen causing significant gastrointestinal and systemic diseases in humans and agricultural animals. Our data demonstrate that Met biosynthesis is essential for S. Typhimurium to grow in synthetic medium and within cultured epithelial cells where Met is depleted in the environment. During systemic infection of mice, the virulence of S. Typhimurium was not affected when either de novo Met biosynthesis or high-affinity Met transport was disrupted alone, but combined disruption in both led to severe in vivo growth attenuation, demonstrating a functional redundancy between de novo biosynthesis and acquisition as a mechanism of sourcing Met to support growth and virulence for S. Typhimurium during infection. In addition, our LC-MS analysis revealed global changes in the metabolome of S. Typhimurium mutants lacking Met biosynthesis and also uncovered unexpected interactions between Met and peptidoglycan biosynthesis. Together, this study highlights the complexity of the interactions between a single amino acid, Met, and other bacterial processes leading to virulence in the host and indicates that disrupting the de novo biosynthetic pathway alone is likely to be ineffective as an antimicrobial therapy against S. Typhimurium

Wild Image Retrieval with HAAR Features and Hybrid DBSCAN Clustering For 3D Cultural Artefact Landmarks Reconstruction

In this digital age large amounts of information, images and videos can be found in the web repositories which accumulate this information. These repositories include personal, historic, cultural, and business event images. Image mining is a limited field in research where most techniques look at processing images instead of mining. Very limited tools are found for mining these images, specifically 3D (Three Dimensional) images. Open source image datasets are not structured making it difficult for query based retrievals. Techniques extracting visual features from these datasets result in low precision values as images lack proper descriptions or numerous samples exist for the same image or images are in 3D. This work proposes an extraction scheme for retrieving cultural artefact based on voxel descriptors. Image anomalies are eliminated with a new clustering technique and the 3D images are used for reconstructing cultural artefact objects. Corresponding cultural 3D images are grouped for a 3D reconstruction engine’s optimized performance. Spatial clustering techniques based on density like PVDBSCAN (Particle Varied Density Based Spatial Clustering of Applications with Noise) eliminate image outliers. Hence, PVDBSCAN is selected in this work for its capability to handle a variety of outliers. Clustering based on Information theory is also used in this work to identify cultural object’s image views which are then reconstructed using 3D motions. The proposed scheme is benchmarked with DBSCAN (Density-Based Spatial Clustering of Applications with Noise) to prove the proposed scheme’s efficiency. Evaluation on a dataset of about 31,000 cultural heritage images being retrieved from internet collections with many outliers indicate the robustness and cost effectiveness of the proposed method towards a reliable and just-in-time 3D reconstruction than existing state-of-the-art techniques

An experimental study on premixed charge compression ignition-direct ignition engine fueled with ethanol and gasohol

This paper investigates the combustion, performance and emission characteristics of a partial Premixed Charge Compression Ignition-Direct Injection (PCCI-DI) Engine with premixed fuels ethanol and gasohol (90% gasoline and 10% ethanol by volume) along with direct injection of diesel fuel into the combustion chamber. The experiments were conducted in a four stroke, naturally aspirated, air cooled, constant speed diesel engine with 20% premixed fuels from no load to full load condition. The addition of premixed fuel enhances the air fuel mixture strength and for that the combustion duration is decreased in dual fuel operation. From this experiment it was observed the 70% and 67% reduction in smoke emission from premixed gasohol and ethanol fuel when compared to neat diesel operation. In addition to that, the oxides of nitrogen emissions were reduced to 30% and 24% for premixed gasohol and ethanol fuel. In particular, premixed gasohol reduces the smoke and oxides of nitrogen emissions more than the ethanol and also, significant increase in brake thermal efficiency was noted in 20% premixed gasohol and ethanol in dual fuel mode, when compared to neat diesel operation

Lasers in Orthodontics - A Review

Understanding the various uses of lasers ,is simply to accept, the cutting edge of present day orthodontics .From the daily orthodontic procedure of surface preparation, bonding, debonding till the adjunctive procedures of frenectomy, canine exposure, gingivectomy can be done with lasers. Record maintenance, cast analysis in 3D, holography, spectroscopy, welding, scanning and many more are done with lasers. Future of painless & faster dentistry, in an orthodontics practice, can all be achieved, to the one that understands the use of lasers in the field of orthodontics. Lasers are our tools of tomorrow, only if we are ready with the knowledge of it today