scholarly journals The Mechanics of Flight

2000 ◽  
Vol 122 (07) ◽  
pp. 54-59
Author(s):  
J. Lawrence Lee
Keyword(s):  
Gas Turbine ◽  
Mechanical Engineering ◽  
Aviation Industry ◽  
Prime Mover ◽  
External Temperature ◽  
Aviation Engines ◽  
Air Conditioning Systems ◽  
Four Cylinders ◽  
Design Construction

This article illustrates contribution of mechanical engineering in the aviation industry. The most obvious role of the mechanical engineer involves the design of engines. From the Wrights’ four cylinders, 12-horsepower engine, aircraft propulsion has evolved into today’s high-bypass turbofans developing over 90,000 pounds of thrust in some instances. The most visible contribution of mechanical engineers to aviation, engines are far from their only contribution. Changes in the design, construction, and capabilities of increasingly modern aircraft challenged the mechanical engineering in many other regards. The introduction of gas-turbine power required a concurrent revolution in manufacturing, test, and maintenance facilities and techniques at the engine builders. As advancements in aircraft construction and power opened the door to higher and faster flight, virtually every system within the airplane had to become more sophisticated, and new ones had to be devised. Air conditioning systems also changed, both to better suit the gas turbine prime mover and to accommodate wider external temperature extremes.

ASPECTS IN BUILDING A COMPANY WEB-SITE AND ITS ROLE FOR THE DEVELOPMENT OF BUSINESS

2018 ◽  
pp. 117-124
Author(s):  
Petar Halachev ◽  
Victoria Radeva ◽  
Albena Nikiforova ◽  
Miglena Veneva
Keyword(s):  
Life Cycle ◽  
Web Site ◽  
The Internet ◽  
A Company ◽  
The Web ◽  
Design Construction ◽  
Made In ◽  
Site Types

This report is dedicated to the role of the web site as an important tool for presenting business on the Internet. Classification of site types has been made in terms of their application in the business and the types of structures in their construction. The Models of the Life Cycle for designing business websites are analyzed and are outlined their strengths and weaknesses. The stages in the design, construction, commissioning, and maintenance of a business website are distinguished and the activities and requirements of each stage are specified.

Microbial Biofilms and Biotechnology – Some Perceptions

2020 ◽  
Vol 09 ◽  
Author(s):  
Subba Rao Toleti
Keyword(s):  
Tissue Culture ◽  
Synthetic Biology ◽  
Industrial Effluents ◽  
Aquatic Environments ◽  
Biochemical Processes ◽  
Microbial Biofilms ◽  
Biofilm Bacteria ◽  
Prophylactic Vaccines ◽  
Design Construction

: The review is an attempt to introduce the readers in brief about biofilms and their implications as well as some new perceptions in biotechnology. Biofilms are adherent microbial communities, which are developed on submerged surfaces in aquatic environments. Biofilms play a significant role in exopolymer production, material deterioration and also cause harmful infections. Further, the role of corrosion causing biofilm bacteria in deterioration of different materials, microbial biofilms and their enzymatic processes in reducing the toxicity of pollutants in industrial effluents are elaborated, along with clean technologies for wastewater treatment. Biotechnology is defined as any technological application that uses biological systems to synthesize or modify products or processes. The applications include biochemical processes, medical care, cell and tissue culture as well as synthetic biology and others. Synthetic biology details about the design, construction of new biological components and systems for useful purposes. Finally, to overcome the limitations that are inherent to the use of cellular host’s, cell-free systems as critical platforms for synthetic biology applications. This mini-review also mentions about new diagnostic products based on enzymes, monoclonal antibodies and engineered proteins as well as novel prophylactic vaccines.

Practitioner Review: Continuity and Change: The Fair Work Act in Aviation

2011 ◽  
Vol 53 (3) ◽  
pp. 392-401 ◽  
Author(s):  
Sue Bussell ◽  
John Farrow
Keyword(s):  
Industrial Relations ◽  
Safety Net ◽  
Aviation Industry ◽  
Continuity And Change ◽  
National Debate ◽  
New Development ◽  
Key Issues ◽  
The Individual ◽  
The Impact

This article begins by discussing the specific industrial relations challenges of the highly competitive aviation industry. It then reflects on the outcome of the recent intense national debate over industrial relations, exploring the consequences of that debate for practice and policy, and discusses some key issues that remain in play. Although the Fair Work Act 2009 may have come about as a reaction to what many perceive as the ‘excesses’ of Work Choices, the new Act does not so much ‘wind back the clock’ as represent a significant new development in Australia’s long and unique industrial relations history. This article will discuss the impact of the changes, to date, made by the Fair Work Act on one organization, including the expansion of the ‘safety net’, and how the new compromise between the role of the ‘collective’ and the role of the ‘individual’ struck by the Act has the potential to fundamentally change the nature and structure of bargaining. We offer these comments as practitioners who have worked under successive industrial relations regimes since the early 1980s.

The Role of Wind on Double Skin Facades in High Rise Office Building

2013 ◽  
Vol 787 ◽  
pp. 711-716
Author(s):  
Daryanto ◽  
Eko Budihardjo ◽  
Wahyu Setyabudi ◽  
Gagoek Hardiman
Keyword(s):  
Energy Conservation ◽  
Building Envelope ◽  
Office Buildings ◽  
Thermal Discomfort ◽  
High Rise ◽  
Double Skin ◽  
The Subject ◽  
Air Conditioning Systems ◽  
Double Skin Facades

There was an indication that high rise buildings in Jakarta was not designed based on energy conservation principles. The most important aspects of the high-rise buildings is energy saving technology located in the building envelope design. Building envelope with a full glass design functions for widening view and enhancing natural lights, even though but it is also increasing energy consumption and thermal discomfort due to the intensity of solar radiation in hot humid climates. During the current decade, the development of double building envelope type (Double Skin Façade: DSF) seemed more just to improve the aesthetics and the use of natural light, while the wind and thermal performance aspects were still lack of serious consideration. Those aspects will be chosen as the subject matter in this research. The research was aimed to investigate and compare the value of heat transfer in the building envelope of high-rise office buildings. Samples were taken from five DSF buildings, with closed and open cavity. CFD software is used for simulation of the five different models of DSF. The research proves that the high-rise office buildings as the research object in Jakarta do not apply energy conservation principle. The utilization of wind in the DSF cavity can reduce temperature and relieve the burden of air conditioning systems that is energy save. An important finding of the research is the need for ventilation in the design of a double skin at high-rise office buildings in the humid tropics.

Modelling the Air-Cooled Gas Turbine: Part 1 — General Thermodynamics

2001 ◽  
Author(s):  
J. B. Young ◽  
R. C. Wilcock
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Real Gas ◽  
Thermal Mixing ◽  
Ideal Gases ◽  
Formal Framework ◽  
Considerable Simplification ◽  
Cycle Efficiency ◽  
General Thermodynamics

This paper is Part I of a study concerned with developing a formal framework for modelling air-cooled gas turbine cycles and deals with basic thermodynamic issues. Such cycles involve gas mixtures with varying composition which must be modelled realistically. A possible approach is to define just two components, air and gas, the latter being the products of stoichiometric combustion of the fuel with air. If these components can be represented as ideal gases, the entropy increase due to compositional mixing, although a true exergy loss, can be ignored for the purpose of performance prediction. This provides considerable simplification. Consideration of three idealised simple cycles shows that the introduction of cooling with an associated thermal mixing loss does not necessarily result in a loss of cycle efficiency. This is no longer true when real gas properties and turbomachinery losses are included. The analysis clarifies the role of the cooling losses and shows the importance of assessing performance in the context of the complete cycle. There is a strong case for representing the cooling losses in terms of irreversible entropy production as this provides a formalised framework, clarifies the modelling difficulties and aids physical interpretation. Results are presented which show the effects on performance of varying cooling flowrates and cooling losses. A comparison between simple and reheat cycles highlights the rôle of the thermal mixing loss. Detailed modelling of the heat transfer and cooling losses is discussed in Part II of this paper.

Marine Gas Turbine Performance Model for More Electric Ships

2011 ◽  
Author(s):  
George M. Koutsothanasis ◽  
Anestis I. Kalfas ◽  
Georgios Doulgeris
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Gas Turbines ◽  
Electric Propulsion ◽  
Operating Conditions ◽  
Prime Mover ◽  
Creep Life ◽  
Hull Fouling ◽  
Turbine Performance

This paper presents the benefits of the more electric vessels powered by hybrid engines and investigates the suitability of a particular prime-mover for a specific ship type using a simulation environment which can approach the actual operating conditions. The performance of a mega yacht (70m), powered by two 4.5MW recuperated gas turbines is examined in different voyage scenarios. The analysis is accomplished for a variety of weather and hull fouling conditions using a marine gas turbine performance software which is constituted by six modules based on analytical methods. In the present study, the marine simulation model is used to predict the fuel consumption and emission levels for various conditions of sea state, ambient and sea temperatures and hull fouling profiles. In addition, using the aforementioned parameters, the variation of engine and propeller efficiency can be estimated. Finally, the software is coupled to a creep life prediction tool, able to calculate the consumption of creep life of the high pressure turbine blading for the predefined missions. The results of the performance analysis show that a mega yacht powered by gas turbines can have comparable fuel consumption with the same vessel powered by high speed Diesel engines in the range of 10MW. In such Integrated Full Electric Propulsion (IFEP) environment the gas turbine provides a comprehensive candidate as a prime mover, mainly due to its compactness being highly valued in such application and its eco-friendly operation. The simulation of different voyage cases shows that cleaning the hull of the vessel, the fuel consumption reduces up to 16%. The benefit of the clean hull becomes even greater when adverse weather condition is considered. Additionally, the specific mega yacht when powered by two 4.2MW Diesel engines has a cruising speed of 15 knots with an average fuel consumption of 10.5 [tonne/day]. The same ship powered by two 4.5MW gas turbines has a cruising speed of 22 knots which means that a journey can be completed 31.8% faster, which reduces impressively the total steaming time. However the gas turbine powered yacht consumes 9 [tonne/day] more fuel. Considering the above, Gas Turbine looks to be the only solution which fulfills the next generation sophisticated high powered ship engine requirements.

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