scholarly journals Thermodynamic Concepts on Efficiency of Aircraft Engines

2021 ◽  
pp. 1-7
Author(s):  
Faradiba Faradiba ◽  
Endah Yuniarti
Keyword(s):  
Meta Analysis ◽  
Heat Engine ◽  
Aircraft Noise ◽  
Maximum Efficiency ◽  
Brayton Cycle ◽  
Aircraft Engines ◽  
Jet Engines ◽  
Analysis Method ◽  
Noise Levels ◽  
Wasted Heat

Along with the development of engine technology to be able to produce maximum efficiency in aircraft jet engines, various modifications were made to the machine tools. Modifications are made by taking into account four main factors, namely: maximum power output, reduced engine weight, low fuel consumption and maximum aircraft payload. This research uses a meta-analysis method, namely the analysis of several research results in line with what has been done previously regarding the efficiency of aircraft jet engines. The thermodynamic concept related to the heat engine which implements the brayton cycle that maximum efficiency can be done by reducing wasted heat energy and maximizing the work produced. From this concept, several attempts to maximize aircraft efficiency, such as modification of design that have a significant impact on weight reduction, fuel barrier design with low fan pressure, high bypass design ratio are also carried out in an effort to reduce aircraft noise levels. Aircraft noise levels can also be minimized by modifying the nozzle and ejector on the engine.

Aircraft Noise Levels, Annoyance and General Health of Residents of Communities contiguous to a Major Airport in Lagos State

2020 ◽  
Vol 8 (4) ◽  
pp. 47-59
Author(s):  
Iheanyichukwu M. Elechi
Keyword(s):  
Health Status ◽  
General Health ◽  
Noise Exposure ◽  
Aircraft Noise ◽  
Poor Health ◽  
Noise Levels ◽  
General Health Status ◽  
Lagos State ◽  
Distant Location ◽  
Self Reported Health Status

The purpose of this study was to investigate the relationship between the aircraft noise exposure, annoyance reactions and health status of the residents living within the vicinity of the Murtala Muhammed International Airport (MMA) in Lagos state, Nigeria. Aircraft noise monitoring was conducted in five locations within the vicinity (0-5Km) of MMA, and a sixth distant location (14km away). Levels of aircraft noise for all five locations within the vicinity of the airport exceeded the EPA Victoria threshold of 75 dB LAmax for the residential area (outdoor). A survey on annoyance induced by aircraft noise exposure and general health status was conducted on 450 local residents in the study locations using the International Commission on Biological Effect of Noise question and a single question that has been applied in Dutch national health care surveys since 1983 on self-reported general health status respectively. Percentage of residents within the vicinity of MMA that were highly annoyed (%HA) exceeded 15% guideline limit stipulated by Federal Interagency Committee on Urban Noise while 14.5% reported poor health status. There was a significant association between the annoyance reactions and aircraft noise levels in the study locations while the association between self-reported health status and aircraft noise levels was not significant. Taken together, the residents within the vicinity of the airport are exposed to aircraft noise levels above permissible limit which may be associated with high annoyance reaction but may not be associated with poor health rating. Evidence-based aircraft noise related policies by government are advocated.

scholarly journals The value of travel time savings in freight transport: a meta-analysis

2021 ◽  
Author(s):  
Jawaher Binsuwadan ◽  
Gerard De Jong ◽  
Richard Batley ◽  
Phill Wheat
Keyword(s):  
Travel Time ◽  
Cost Benefit Analysis ◽  
Meta Analysis ◽  
Cost Benefit ◽  
Freight Transport ◽  
Survey Respondent ◽  
Analysis Method ◽  
Marginal Rate ◽  
Travel Time Savings ◽  
Time Savings

AbstractThe value of freight travel time savings (VFTTS) is a monetary value that is considered an important input into cost–benefit analysis and traffic forecasting. The VFTTS is defined as the marginal rate of substitution between travel time and cost and may therefore differ across firms, time and countries. The paper aims to explain variations in the VFTTS by using the meta-analysis method. The analysis covers 106 monetary valuations extracted from 56 studies conducted from 1988 to 2018 in countries across the globe. The meta-analysis method determines the factors that have an impact on these VFTTS variations. The paper briefly introduces the VFTTS concept and describes the adopted meta-analysis methodology, wherein different meta-models are used in VFTTS estimations. The results highlight the necessity of including multiple explanatory variables to ensure adequate explanation of the VFTTS variations. The findings also show that GDP per capita, transport mode and type of survey respondent are statistically significant variables. The paper sheds some light on the variations, thereby advancing the understanding of each factor’s effects on the VFTTS. Furthermore, meta-model outcomes are used to generate new values of travel time savings for different transport modes in freight transport, for several countries. These implied VFTTS can be used as benchmarks to assess existing evidence or provide new evidence to countries where no such values exist.

Effects of Increased Noise Levels by Supersonic Aircraft on Annoyance Levels and Time Estimations

1980 ◽  
Vol 50 (2) ◽  
pp. 563-569
Author(s):  
John A. Allen
Keyword(s):  
Aircraft Noise ◽  
Noise Levels ◽  
Supersonic Aircraft ◽  
International Airport

Several tests designed to assess the effects of increased noise levels created by the Concorde supersonic aircraft were administered to 48 residents living around Dulles International Airport and 31 persons not living near an airport. Results of a pretest questionnaire and lack of significant changes in annoyance levels and time estimations indicate that, while airport-area residents may be more conscious of aircraft noise, changes in the perceived intensities of sounds may not occur.

META ANALYSIS METHOD OVERVIEW OF MODELS USED IN OCCUPATIONAL SAFETY TRAININGS

2021 ◽  
Vol 6 (15) ◽  
pp. 482-490
Author(s):  
Filiz ARICAK ◽  
Evren ÇAĞLARER
Keyword(s):  
Work Environment ◽  
Occupational Safety ◽  
Meta Analysis ◽  
Health And Safety ◽  
Safety Training ◽  
Working Environment ◽  
Future Generations ◽  
Analysis Method ◽  
Training Models ◽  
Safety Procedures

In this study, an analysis of independent studies dealing with occupational safety training in different learning environments, in which various learning materials are used, was carried out. As a method, meta-analysis method was used. For this purpose, databases were used to collect national and international articles and papers suitable for the purpose of the study. Studies that did not mention the tools, equipment and environment used in education in the collected studies were excluded from the research, and 18 studies were included in the meta-analysis. The data obtained studies are categorized according to the education models, the sectors in which the education is applied and the characteristics of the participants in the education. As it is known, occupational health and safety procedures aim at a healthy and reliable working environment for its employees. However, the ultimate goal is to raise not only employees but also future generations with this awareness. The most important instrument of this is undoubtedly education. For this reason, it is necessary to develop training models suitable for the work environment, age, gender and every conceivable situation.

scholarly journals Exposure to Road, Railway, and Aircraft Noise and Arterial Stiffness in the SAPALDIA Study: Annual Average Noise Levels and Temporal Noise Characteristics

2017 ◽  
Vol 125 (9) ◽  
pp. 097004 ◽  
Author(s):  
Maria Foraster ◽  
Ikenna C. Eze ◽  
Emmanuel Schaffner ◽  
Danielle Vienneau ◽  
Harris Héritier ◽  
...  
Keyword(s):  
Arterial Stiffness ◽  
Aircraft Noise ◽  
Noise Levels ◽  
Annual Average ◽  
Temporal Noise ◽  
Noise Characteristics

scholarly journals META-ANALYSIS: TYPES OF MEDIA AND CHARACTERISTICS OF PHYSICAL MATERIALS SUITABLE FOR PHYSICS LEARNING MEDIA BASED ON ADOBE FLASH SOFTWARE

2020 ◽  
Vol 8 (1) ◽  
pp. 24
Author(s):  
Hasbi Azis ◽  
Mutia Risma ◽  
Sinta Yolanda ◽  
Desnita Desnita ◽  
Usmeldi Usmeldi
Keyword(s):  
Meta Analysis ◽  
Secondary Data ◽  
Analysis Method ◽  
Physics Learning ◽  
Computer Based Learning ◽  
Adobe Flash ◽  
Temperature Heat ◽  
Computer Based ◽  
The Media ◽  
Physical Materials

This research aimed to analyze the types of media and the characteristics of physics materials that are suitable for use in the development of physics learning media, using Adobe Flash software. The research uses a meta-analysis method, which is a method for analyzing many of the research that has been done. This research uses secondary data obtained from previous research in the form of journals related to the media using Adobe Flash software for senior high school physics subjects. The journals examined in this research consisted of 20 research articles that developed an adobe flash-based interactive learning media for physics learning in senior high schools. The number of articles reviewed consisted of 3 articles from international journals and 17 articles from national journals. Based on the results of the analysis that has been done, found 13 physics materials obtained from 20 journals analyzed, where the concepts of temperature, heat, and transfer are the most widely used material as content in the development of physics learning media based on Adobe Flash software. While the type of media that is widely used in computer-based learning media.

Analysis of the last 10 years of articles and theses on authentic learning: A meta-analysis study

2020 ◽  
Vol 8 (3) ◽  
pp. 78-91
Author(s):  
Ezgi Pelin Yildiz
Keyword(s):  
Sampling Method ◽  
Meta Analysis ◽  
Authentic Learning ◽  
Nursing Curriculum ◽  
Learning Technology ◽  
Learning Approaches ◽  
Analysis Method ◽  
Network Learning ◽  
Purposeful Sampling ◽  
The World

The aim of this research is to examine articles and thesis studies in the field of authentic learning approaches and applications in education in the last 10 years and to reveal the trends in this context. In the methodology part of the research, the meta-analysis method was used. Meta-analysis studies refers to the critical review and integration of the findings of separate studies. For the purpose of the study, a total of 111 pieces of research, published between 2010 and 2021 and selected by purposeful sampling method were analyzed. Databases used in research are Eric, IEEE Xplore, Ebsco, Springer, Science Direct, Scopus, Web of Sciences. Authentic learning approaches and applications in education throughout the world were examined under 16 criteria. These data were interpreted based on percentage and frequency. As a result, authentic learning approaches and applicationare integrated in many fields such as ICT, engineering, network learning technology, nursing, curriculum & instruction, geography, medicine and more.   Keywords: Learning Approaches, Meta-Analysis, Publication Classification, Authenic, Analysis

The Role of Internal Irreversibilities in the Performance and Stability of Power Plant Models Working at Maximum ϵ-Ecological Function

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gabriel Valencia-Ortega ◽  
Sergio Levario-Medina ◽  
Marco Antonio Barranco-Jiménez
Keyword(s):  
Power Plants ◽  
Heat Engine ◽  
Combined Cycle ◽  
Ecological Function ◽  
Operating Conditions ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Engine Model ◽  
Improved Stability ◽  
The Stability

Abstract The proposal of models that account for the irreversibilities within the core engine has been the topic of interest to quantify the useful energy available during its conversion. In this work, we analyze the energetic optimization and stability (local and global) of three power plants, nuclear, combined-cycle, and simple-cycle ones, by means of the Curzon–Ahlborn heat engine model which considers a linear heat transfer law. The internal irreversibilities of the working fluid measured through the r-parameter are associated with the so-called “uncompensated Clausius heat.” In addition, the generalization of the ecological function is used to find operating conditions in three different zones, which allows to carry out a numerical analysis focused on the stability of power plants in each operation zone. We noted that not all power plants reveal stability in all the operation zones when irreversibilities are considered through the r-parameter on real-world power plants. However, an improved stability is shown in the zone limited by the maximum power output and maximum efficiency regimes.

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