scholarly journals Production processes and statistical analysis of ceramic liner-hole parameters for sustainability and improved thermal efficiency of clean biomass stoves

2021 ◽  
Vol 6 ◽  
pp. 23
Author(s):  
Kenneth Donkor ◽  
George Yaw Obeng ◽  
Richard Opoku ◽  
Anthony Agyei-Agyemang
Keyword(s):  
Thermal Efficiency ◽  
Hole Diameter ◽  
Material Composition ◽  
Distribution Analysis ◽  
Practical Applications ◽  
Engineering Ceramic ◽  
Production Processes ◽  
Ceramic Liner ◽  
Industrial Operations ◽  
Biomass Stoves

In engineering, ceramic liners are used as heat retention, insulation, and wear-resistant components for industrial and domestic applications. However, due to lack of production standards, particularly under small industrial operations, there is variation in liner-hole diameter and inter-hole spacing of liners used in clean biomass stoves. This study assessed the production processes and analysed ceramic liner-hole diameters and inter-hole spacings for standardisation. Standardising liner-hole parameters is a major process towards sustainability and improved efficiency. Methods employed were − material composition, particle size distribution analysis, study of production processes, and 51 liner-hole diameters and 66 inter-holes spacing were randomly sampled and analysed. The results indicated material composition of clay (70%), sand (23%), and sawdust (7%) of various particle sizes. A flow chart diagram of 7 production processes was created for standardisation. At 95% C.I, liner-hole diameter of Ø20.8 ± 2(0.66) mm and inter-hole spacing of 27.5 ± 2(1.06) mm were determined. Mean liner-hole diameter of Ø21.03 mm resulted in a relatively high thermal efficiency, ηT =37%. For practical applications, liner-hole diameter of Ø21 mm and inter-hole spacing of 30 mm are recommended. Standardising the production processes and the liner-hole parameters will contribute to sustainable production and thermal efficiency improvement.

Manpower, Labor Absorption, and Employment in Colombia

1976 ◽  
Vol 18 (2) ◽  
pp. 237-242
Author(s):  
David T. Geithman
Keyword(s):  
Modern Sector ◽  
Practical Applications ◽  
Policy Responses ◽  
Land Redistribution ◽  
Production Processes ◽  
Employment Situation ◽  
Traditional Sector ◽  
Active Policy ◽  
Additional Labor ◽  
Unemployment Problem

The Zudak paper (1976) restates in the Colombian context, without adding much that is new, some of the difficulties inherent in defining for practical applications the capital, labor, and output variables. He decides that the output-to-capital ratio in the case of Colombia is about .6 rather than .5 as suggested by Geithman and Landers in an earlier article in this journal (1973). Zudak concludes that the Colombian unemployment problem might best be managed by (1) improving the operation of the labor market, which Geithman-Landers advocated earlier, and (2) reducing the length of the work week. The latter suggestion, he apparently argues, is preferable to other possible policy responses to the employment situation recommended by Geithman-Landers. These consist primarily of (a) the development of additional labor-using production processes in the modern sector to expand the range of technical substitutability in that sector; (b) an active policy of income redistributton in the direction of greater equality in order to spur the demand for traditional sector output and dampen the demand for modern sector goods; and (c) a serious move toward land redistribution and reform as one available means of loosening the country's capital constraint.

About Simplifications in Gas Turbine Performance Calculations

2007 ◽  
Author(s):  
Joachim Kurzke
Keyword(s):  
Gas Turbine ◽  
Real World ◽  
Thermal Efficiency ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Flow Distortion ◽  
One Dimensional ◽  
Practical Applications ◽  
Turbine Performance ◽  
In Series

Any gas turbine performance simulation tool employs simplifications, some more, some less. It depends on the intent of the simulation which simplifications are appropriate. For beginners, many are necessary for teaching how the gas turbine works from principle. For practical applications — because of the accuracy requirements — many simplifications introduced in textbooks are not appropriate. This paper comments on the simplifications that are typically made. Simplified gas property models are quite acceptable for ideal cycle analysis. For the examination of real cycles, however, especially the model of the burner should be better than those described in most textbooks. This is because these models yield the best cycle efficiency at stoichiometric fuel-air-ratio while a realistic burner model leads to the conclusion that the best thermal efficiency happens to be at significantly lower fuel-air-ratios respectively temperatures. For off-design simulations many simplifications have the aim to avoid iterative solutions or restricting the algorithms to one-dimensional iterations. If more than one iteration variable shows up — which is the case with multi-spool engine simulations — then the problem is solved with fitting several one-dimensional iterations into each other. This methodology is described in most textbooks, but it is nearly never used in industry because the logic is more complex than necessary and difficult to adapt to special needs. The seeming simplification is actually a complication when applied to real world problems. Universities should teach as a standard the multidimensional Newton Raphson iteration technique which allows writing gas turbine cycle codes with nearly no restriction to the methods of formulating the laws of physics. The consequence of simplified mathematics is often an off-design simulation which does not employ compressor and turbine maps. Such a methodology yields accurate values for thermal efficiency respectively specific fuel consumption only within a narrow range of operating conditions; the accuracy of the results is not sufficient for real world applications. Of course also in programs for industrial use the reality is modeled with many compromises. Some simplifications which have not so obvious consequences are discussed. For example, there is an influence of the speed-flow characteristics in the booster map on its operating line if an often used type of fan performance representation is employed. Another example is that an oversimplified description of what happens in the compressor interduct can lead to wrong conclusions when the effects of inlet flow distortion on the stability of compressors in series are sought.

scholarly journals Ultrafast Deep-Ultraviolet Laser-Induced Voltage Response of Pyrite

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1555
Author(s):  
Xuecong Liu ◽  
Yudong Li ◽  
Haoqiang Wu ◽  
Yawen Yu ◽  
Honglei Zhan ◽  
...  
Keyword(s):  
Laser Energy ◽  
Low Cost ◽  
Response Speed ◽  
Voltage Response ◽  
Induced Voltage ◽  
High Concentration ◽  
Uv Photodetectors ◽  
Practical Applications ◽  
Production Processes ◽  
Deep Ultraviolet

Ultrafast, high-sensitivity deep-ultraviolet (UV) photodetectors are crucial for practical applications, including optical communication, ozone layer monitoring, flame detection, etc. However, fast-response UV photodetectors based on traditional materials suffer from issues of expensive production processes. Here, we focused on pyrite with simultaneously cheap production processes and ultrafast response speed. Nanoseconds photovoltaic response was observed under UV pulsed laser irradiation without an applied bias at room temperature. In addition, the response time of the laser-induced voltage (LIV) signals was ~20 ns, which was the same as the UV laser pulse width. The maximum value of the responsivity is 0.52 V/mJ and the minimum value of detectivity was about to ~1.4 × 1013 Jones. When there exists nonuniform illumination, a process of diffusion occurs by which the carriers migrate from the region of high concentration toward the region of low concentration. The response speed is limited by a factor of the diffusion of the carriers. With an increment in laser energy, the response speed of LIV is greatly improved. The high response speed combined with low-cost fabrication makes these UV photodetectors highly attractive for applications in ultrafast detection.

scholarly journals Effect of Parameters Behavior of Simarouba Methyl Ester Operated Diesel Engine

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4973
Author(s):  
Keerthi Kumar N. ◽  
N. R. Banapurmath ◽  
T. K. Chandrashekar ◽  
Jatadhara G. S. ◽  
Manzoore Elahi M. Soudagar ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Hole Diameter ◽  
Design Parameters ◽  
Engine Operation ◽  
Brake Thermal Efficiency ◽  
Smoke Opacity

Being an energy source of another origin, the compression ignition (CI) engine’s typical design parameters might not suit Simarouba oil methyl ester (SuOME). Present experimental investigation targets are determining the effects of engine design parameters, including fuel injection pressure and nozzle geometry, on the engine, concerning performance and emissions such as carbon monoxide (CO), unburnt hydrocarbon (HC), oxides of nitrogen (NOx), and smoke opacity, with SuOME as fuel. Comparisons of brake thermal efficiency (BTE) and different emissions from the engine tailpipe were performed for different fuel injection pressures and a number of injector holes and diameter of orifices were opened in the injector to find the optimum combination to run the engine with SuOME. It was observed that the combined effect of an increase in injection pressure of 240 bar from 205 bar, and increasing number of injector holes from three to six with reduced injector hole diameters from 0.2 to 0.3 mm, recorded higher brake thermal efficiency with reduced emission levels for the SuOME mode of operation compared to the baseline standard operation with SuOME. For 240 bar compared to 205 bar of injection pressure (IP) for SuOME, the BTE increased by 2.35% and smoke opacity reduced by 1.45%. For six-hole fuel injectors compared to three-hole injectors, the BTE increased by 3.19%, HC reduced by 9.5%, and CO reduced by 14.7%. At 240 bar IP, with the six-hole injector having a 0.2 mm hole diameter compared to the 0.3 mm hole diameter, the BTE increased by 5%, HC reduced by 5.26%, CO reduced by 25.61%, smoke reduced by 10%, while NOx increased marginally by 0.27%. Hence, the six-hole FI, 240 IP, 0.2 mm FI diameter holes are suitable for diesel engine operation fueled by Simarouba biodiesel.

scholarly journals Effects of Nanofluids in Improving the Efficiency of the Conical Concentrator System

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 28
Author(s):  
Alsalame Haedr Abdalha Mahmood ◽  
Muhammad Imtiaz Hussain ◽  
Gwi-Hyun Lee
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Thermal Efficiency ◽  
Fossil Fuels ◽  
Distilled Water ◽  
Flow Rates ◽  
Practical Applications ◽  
Heat Transfer Fluids ◽  
Significant Research ◽  
Collector Efficiency

Fossil fuels are being depleted, resulting in increasing environmental pollution due to greenhouse gases and, consequently, emerging detrimental environmental problems. Therefore, renewable energy is becoming more important; hence, significant research is in progress to increase efficient uses of solar energy. In this paper, the thermal performance of a conical concentrating system with different heat transfer fluids at varied flow rates was studied. The conical-shaped concentrator reflects the incoming solar radiation onto the absorber surface, which is located at the focal axis, where the collected heat is transported through heating mediums or heat transfer fluids. Distilled water and nanofluids (Al2O3, CuO) were used in this study as the heat transfer fluids and were circulated through the absorber and the heat storage tank in a closed loop by a pump to absorb the solar radiation. The efficiency of the conical concentrating system was measured during solar noon hours under a clear sky. The collector efficiency was analyzed at different flow rates of 2, 4, and 6 L/min. The thermal efficiency, calculated using different heat transfer fluids, were 72.5% for Al2O3, 65% for CuO, and 62.8% for distilled water. Comparing the thermal efficiency at different flow rates, Al2O3 at 6 L/min, CuO at 6 L/min, and distilled water at 4 L/min showed high efficiencies; these results indicate that the Al2O3 nanofluid is the better choice for use as a heating medium for practical applications.

scholarly journals Competitiveness of Manufacturing Industry in India: Need for Flexible Manufacturing Systems

2019 ◽  
Vol 8 (12) ◽  
pp. 3041-3047
Keyword(s):  
Cost Effectiveness ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Manufacturing Industry ◽  
Global Competition ◽  
Ongoing Process ◽  
Manufacturing Operations ◽  
Production Processes ◽  
Industrial Operations

The ongoing process of globalization has brought about radical changes in industry and business across the globe. Because of global competition, there is ever growing need for higher productivity as well as quality in production. So also, there is a imminent need for improving cost effectiveness in industrial operations to withstand the competitive pressures. So, every business constantly seeks innovative ways of production processes for improving their competitiveness. In this context, this study looks into the need for Flexible Manufacturing Systems (FMSs) in Indian, the effectiveness of FMS in raising the productivity of manufacturing operations, FMS adoption being still in its infancy in India. FMS concept, its suitability, its applications and main trends are discussed. Suitable suggestions for effective FMS implementation in Indian industry are made.

A New System For Optomanual Semiautomatic Quantitative Image Analysis

1977 ◽  
Vol 35 ◽  
pp. 210-211
Author(s):  
H.P. Rohr
Keyword(s):  
Image Analysis ◽  
Volume Density ◽  
List Type ◽  
Distribution Analysis ◽  
Type Number ◽  
Point Counting ◽  
Human Eye ◽  
Quantitative Image ◽  
Point Density ◽  
Electronic Counting

Today, in image analysis the broadest possible rationalization and economization have become desirable. Basically, there are two approaches for image analysis: The image analysis through the so-called scanning methods which are usually performed without the human eye and the systems of optical semiautomatic analysis completely relying on the human eye.The new MOP AM 01 opto-manual system (fig.) represents one of the very promising approaches in this field. The instrument consists of an electronic counting and storing unit, which incorporates a microprocessor and a keyboard for choice of measuring parameters, well designed for easy use.Using the MOP AM 01 there are three possibilities of image analysis:the manual point counting,the opto-manual point counting andthe measurement of absolute areas and/or length (size distribution analysis included).To determine a point density for the calculation of the corresponding volume density the intercepts lying within the structure are scanned with the light pen.

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

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