Fluid Flow and Heat Transfer in Serpentine Channels at Low Reynolds Numbers

Fluid flow and heat transfer in a two-dimensional serpentine channel was investigated numerically for Reynolds numbers between 175 and 725. A fifth-order finite differencing scheme was employed to carry out the computations. Three different geometries were studied. All three geometries consisted of the same wave length and the same shape of top and bottom walls, but different channel heights. In addition, two different inlet/outlet boundary conditions were investigated. It was found that the heat transfer as well as the pressure drop increase with decreasing channel height. For a given channel height, the results show that the time-averaged mean Nusselt number as well as the time averaged mean friction factor scale linearly with the Reynolds number.Air Conditioning and Refrigeration Project 6

Study of second order upwind differencing in a recirculating flow

The accuracy and stability of the second order upwind differencing scheme was investigated. The solution algorithm employed is based on a coupled solution of the nonlinear finite difference equations by the multigrid technique. Calculations have been made of the driven cavity flow for several Reynolds numbers and finite difference grids. In comparison with the hybrid differencing, the second order upwind differencing is somewhat more accurate but it is not monotonically accurate with mesh refinement. Also, the convergence of the solution algorithm deteriorates with the use of the second order upwind differencing

Convergence Speed of the Consensus Algorithm with Interference and Sparse Long-Range Connectivity

We analyze the effect of interference on the convergence rate of average consensus algorithms, which iteratively compute the measurement average by message passing among nodes. It is usually assumed that these algorithms converge faster with a greater exchange of information (i.e., by increased network connectivity) in every iteration. However, when interference is taken into account, it is no longer clear if the rate of convergence increases with network connectivity. We study this problem for randomly-placed consensus-seeking nodes connected through an interference-limited network. We investigate the following questions: (a) How does the rate of convergence vary with increasing communication range of each node? and (b) How does this result change when each node is allowed to communicate with a few selected far-off nodes? When nodes schedule their transmissions to avoid interference, we show that the convergence speed scales with $r^{2-d}$, where $r$ is the communication range and $d$ is the number of dimensions. This scaling is the result of two competing effects when increasing $r$: Increased schedule length for interference-free transmission vs. the speed gain due to improved connectivity. Hence, although one-dimensional networks can converge faster from a greater communication range despite increased interference, the two effects exactly offset one another in two-dimensions. In higher dimensions, increasing the communication range can actually degrade the rate of convergence. Our results thus underline the importance of factoring in the effect of interference in the design of distributed estimation algorithms.Comment: 27 pages, 4 figure

Flow and heat transfer in curved ducts

Imperial Users onl

Skip Trie Matching for Real-Time OCR Output Error Corrrection on Smartphones

Many Visually Impaired individuals are managing their daily activities with the help of smartphones. While there are many vision-based mobile applications to identify products, there is a relative dearth of applications for extracting useful nutrition information. In this report, we study the performance of existing OCR systems available for the Android platform, and choose the best to extract the nutrition facts information from U.S grocery store packages. We then provide approaches to improve the results of text strings produced by the Tesseract OCR engine on image segments of nutrition tables automatically extracted by an Android 2.3.6 smartphone application using real-time video streams of grocery products. We also present an algorithm, called Skip Trie Matching (STM), for real-time OCR output error correction on smartphones. The algorithm’s performance is compared with Apache Lucene’s spell checker. Our evaluation indicates that the average run time of the STM algorithm is lower than Lucene’s. (68 pages

Maternal Periodontitis and Low Birth Weight Babies

Introduction: Low birth weight in developing countries is primarily because of poor maternal health and nutrition. If maternal health plays such an important role in the child’s development, all the means of preventing problems among the pregnant women is of utmost importance. Aim: This study was conducted to assess the relationship between maternal periodontitis and the weight of the baby after birth. Materials and methods: The subjects in the present longitudinalstudy were chosen from the outpatients of Gynecology Department of the People’s Hospital over a period of 1 month. The periodontal status was assessed based on community periodontal index (CPI) and loss of attachment (LOA). Results: All the participants demonstrated periodontal pockets with more than half the population (56%) presenting shallow pockets (pockets of 4-5 mm). Conclusion: In the present study, periodontal status of the mother was significantly related to delivery of low birth weight babies. Thus it can be concluded that periodontitis may be associated with delivery of low birth weight babies

BENTUK PELAYANAN KESEHATAN YANG BAIK UNTUK NARAPIDANA PEREMPUAN HAMIL DI LEMBAGA PEMASYARAKATAN

Jurnal ini membahas tentang pentingnya memberikan pelayanan kesehatan yang baik kepada narapidana perempuan yang sedang hamil di dalam sistem penjara. Kesehatan ibu dan bayi merupakan aspek kritis yang harus diperhatikan selama masa kehamilan dalam lingkungan penjara. Tulisan ini menguraikan prinsip-prinsip penting dalam memberikan pelayanan kesehatan yang baik, termasuk pengujian kehamilan, pemantauan kesehatan rutin, perawatan prenatal yang memadai, perawatan pasca persalinan, pelayanan gizi yang memadai, dan dukungan kesehatan mental. Selain itu, aspek hak asasi manusia juga harus diperhatikan dalam memberikan pelayanan ini. Dengan memperhatikan semua aspek ini, diharapkan narapidana perempuan yang hamil dapat menerima perawatan kesehatan yang optimal untuk menjaga kesehatan mereka dan bayi yang dikandungnya selama masa hukumannya. Jurnal ini membahas kerangka kerja penting untuk menciptakan lingkungan yang mendukung kesehatan dan kesejahteraan narapidana perempuan hamil dalam sistem peradilan pidana

Calculations of hot gas ingestion for a STOVL aircraft model

Hot gas ingestion problems for Short Take-Off, Vertical Landing (STOVL) aircraft are typically approached with empirical methods and experience. In this study, the hot gas environment around a STOVL aircraft was modeled as multiple jets in crossflow with inlet suction. The flow field was calculated with a Navier-Stokes, Reynolds-averaged, turbulent, 3D computational fluid dynamics code using a multigrid technique. A simple model of a STOVL aircraft with four choked jets at 1000 K was studied at various heights, headwind speeds, and thrust splay angles in a modest parametric study. Scientific visualization of the computed flow field shows a pair of vortices in front of the inlet. This and other qualitative aspects of the flow field agree well with experimental data