Heat/mass transfer in smooth and ribbed rectangular serpentine passages of different aspect ratio\u27s and orientation

An experimental study of heat/mass transfer in rectangular smooth and ribbed serpentine passages with and without rotation in two different aspect ratios (1:4 and 4:1) channel is performed for two different orientations of the test section (90-degree and 45-degree). The Reynolds number is varied in the range of 5,000 to 40,000 and rotation numbers in the range of 0-0.12. Such passages are encountered close to the mid-chord sections or towards the trailing edge of the turbine blade. Two different configurations of the Normal ribs (e/Dh=0.3125, P/e=8 and e/Dh=0.156, P/e=11.2) are placed on the leading and the trailing sides. The experiments are conducted in a rotating two-pass coolant channel facility using the naphthalene sublimation technique. For purposes of comparison, selected measurements are also performed in a 1:1 cross-section. The local mass-transfer data in the fully developed region is averaged to study the effect of the Reynolds and the Rotation numbers. The span-wise mass transfer distributions in the smooth and the ribbed cases are also examined

Simulation of Heat Transfer Phenomenon in Furnace Using Fluent-Gambit

In this project work the simulation of heat transfer and the temperature curve in the furnace is computed out using gambit and fluent software. Comparison of temperature profiles of the material in the furnace using constant temperature heat source and linearly varying temperature of the heat source for unsteady state is done. Also the time for temperature to become steady is compared. The material used in the furnace is aluminum and conduction is the mode of heat transfer, the side walls are adiabatic and maintained at ambient temperature. Also the density variation and solidification-melti ng curve of material filled inside are compared for both conditions. The geometry used is very simple, similar to muffle furnace. The problem will be solved by using the software package FLUENT – GAMBIT. FLUENT is a computational fluid dynamics (CFD) software package to simulate fluid problems. It uses the finite-volume method to solve the governing equations for a fluid. It provides the capability to use different physical models such as incompressible or compressible, in viscid or viscous, laminar or turbulent, etc. Geometry and grid generation is done using GAMBIT which is the preprocessor bundled with FLUENT

High Performance Power Spectrum Analysis Using a FPGA Based Reconfigurable Computing Platform

Power-spectrum analysis is an important tool providing critical information about a signal. The range of applications includes communication-systems to DNA-sequencing. If there is interference present on a transmitted signal, it could be due to a natural cause or superimposed forcefully. In the latter case, its early detection and analysis becomes important. In such situations having a small observation window, a quick look at power-spectrum can reveal a great deal of information, including frequency and source of interference. In this paper, we present our design of a FPGA based reconfigurable platform for high performance power-spectrum analysis. This allows for the real-time data-acquisition and processing of samples of the incoming signal in a small time frame. The processing consists of computation of power, its average and peak, over a set of input values. This platform sustains simultaneous data streams on each of the four input channels.Comment: 5 pages, 3 figures. Published in the Proceedings of the IEEE International conference on Reconfigurable Computing and FPGAs (ReConFig 2006). Article also available at http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4100006&isnumber=409995

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

Background: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. Methods: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. Findings: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96–1·28). Interpretation: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. Funding: National Institute for Health Research Health Services and Delivery Research Programme

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

BACKGROUND: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. METHODS: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. FINDINGS: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96-1·28). INTERPRETATION: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. FUNDING: National Institute for Health Research Health Services and Delivery Research Programme

Development of spintronics devices and Type 1 heterojunctions from graphene nanoribbon superlattices

Graphene physics and edge effects have a substantial influence on the electronic structure of graphene based nanomaterials. In this work, a detailed investigation of the edge effects of graphene nanoribbon superlattices is implemented in order to guide the discovery, design, and development of novel electronic devices. Graphene nanoribbon superlattices are low-dimensional carbon materials that are formed on making junctions with different graphene nanoribbons as components. This leads to a variety of interesting properties as the component ribbons have differing band structures, and edge effects lead to interesting physical applications. Using Density Functional Theory (DFT), we calculate quasiparticle bandgaps, projected density of states and other electronic structure properties to find that based on the superlattice topology, we can form Type 1 heterojunctions and materials with applications in spintronics. These results were used in conjunction with a nearest-neighbor tight-binding approach to differentiate between three structures formed from graphene nanoribbon superlattices with different interface regions. It was found that slight variations in the interface configuration and structure can result in Type 1 heterojunctions whose behavior could be predicted from a simple 1D effective mass model, or devices with localized magnetism at the interface sites with potential applications in spintronics. For devices with magnetic interfaces, we show the possibility of forming ferrimagnetic and anti-ferromagnetic materials systems and their possible application areas. We also explain the trends in total and absolute magnetism for these superlattice as parameters of the system considered

Impact of the 2017 ACC/AHA guidelines on the prevalence of hypertension among Indian adults: Results from a cross-sectional survey

BackgroundThe impact of the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for diagnosis and management of hypertension on the prevalence of hypertension in India is unknown.MethodsWe analyzed data from the Cardiac Prevent 2015 survey to estimate the change in the prevalence of hypertension. The JNC8 guidelines defined hypertension as a systolic blood pressure of ≥140 ​mmHg or diastolic blood pressure of ≥90 ​mmHg. The 2017 ACC/AHA guidelines define hypertension as a systolic blood pressure of ≥130 ​mmHg or diastolic blood pressure of ≥80 ​mmHg. We standardized the prevalence as per the 2011 census population of India. We also calculated the prevalence as per the World Health Organization (WHO) World Standard Population (2000-2025).ResultsAmong 180,335 participants (33.2% women), the mean age was 40.6 ​± ​14.9 years (41.1 ​± ​15.0 and 39.7 ​± ​14.7 years in men and women, respectively). Among them, 8,898 (4.9%), 99,791 (55.3%), 35,694 (11.9%), 23,084 (12.8%), 9,989 (5.5%) and 2,878 (1.6%) participants belonged to age group 18-19, 20-44, 45-54, 55-64, 65-74 and ​≥ ​75 years respectively. The prevalence of hypertension according to the JNC8 and 2017 ACC/AHA guidelines was 29.7% and 63.8%, respectively- an increase of 115%. With the 2011 census population of India, this suggests that currently, 486 million Indian adults have hypertension according to the 2017 ACC/AHA guidelines, an addition of 260 million as compared to the JNC8 guidelines.ConclusionAccording to the 2017 ACC/AHA guidelines, 3 in every 5 Indian adults have hypertension