May 2013 (Journal of Modern Science and Technology)

May 2013 (Journal of Modern Science and Technology)

Total Articles - 4

Pages 1-18

Author: Shamail Ahmad and Iftikhar Ahmed Channa

It is an established fact that the grain size of the steel has a marked impact on its mechanical properties. Steel with large grain size has lower yield strength, tensile strength, impact toughness, fatigue life and susceptibility to brittle fracture while has better creep resistance. Besides this it also affects the corrosion resistance and other properties of the steel. The purpose of this paper is to establish a definite mathematical relationship between the ferritic, pearlitic and average grain size for the steel having ferritic-pearlitic structure. For this reason a hot rolled AISI 1060 sample is selected and are cut into three pieces. Out of these three samples, one sample is normalized from 815 C and one from 845 C. Then all the samples are subjected to volume fraction, ferritic, pearlitic and average grain size measurements. Ferritic and pearlitic grain sizes are measured by Intercept Method for Two-Constituents and average grain size is measured by Heyn/Hilliard/Abrams Intercept Method. The results have shown that the experimentally measured average grain size of steel is equal to the sum of the products of ferritic and pearlitic grain sizes with their relative volume fractions that is it satisfies the rule of mixtures.

Pages 19-29

Author: Md Abdus Salam, Nc Chattopadhyay, Md Jalal Uddin Rumi and H.E.M.Zahidul Islam Eunus

With introduction of Jet powered Aircraft in 1950s Engine Jet Noise menace. With the current rate of growth of aviation and extensive utilization of jet powered commercial airliners it is expected that total aviation (civil and military) is slightly to go by more than 4%. In these aircraft, modern technologies are being used where the use of jet engines is inescapable. All types of engines are generating noise which has negative impact on environment as well as human being. Although individual aircraft has become quieter over the past 30 years but flight frequencies have increased. High speedy supersonic aircrafts are also using for military purposes. This paper focuses on the review of various methods employed in the past to reduce the jet noise as also the future expected methodologies hence the subject deals with sources, causes of noise and its propagation with a solution to prevent. Though it is a vast field in aviation sector, this topic is discussed in brief.

Pages 30-44

Author: Md. Ariful Islam, Md. Asadujjaman, Md. Nuruzzaman and Md. Mosharraf Hossain

Hospital beds and other similar types of beds are used not only in hospitals, but also in other health care facilities and settings, such as nursing homes, assisted living facilities, outpatient clinics, and in home health care. There has more variations in the design of hospital bed and no one is designed with considering anthropometric data of Bangladesh. Anthropometry involves the systematic measurement of the physical properties of the human body, primarily dimensional descriptors of body size and shape which can be used to identify the physical dimensions of hospital bed. In this study, 35 patients and 35 doctors have given their opinion through a set of questionnaires. A total of 103 students of Rajshahi University of Engineering and Technology (RUET) participated for anthropometric measurement. Four anthropometric dimensions related to normal hospital bed have measured using meter scale. The result shows that back pain, fatigue, blood circulation problem, comfort and sleep are related to the anthropometric factors of hospital bed. Analytic Hierarchy Process (AHP) analysis shows that patient bed length is most responsible for patient physical demand which is related to anthropometric factor stature. Linear regression analysis shows the relationship of stature with others anthropometric measurement related to normal hospital bed. This study will help the furniture industries in Bangladesh to design the products and will provide a clear conception about physical dimensions of Bangladeshi people.

Pages 45-51

Author: Nikhil Verma and Md Rejwanul Haque

Distance Measuring Equipment (DME) is based on the radar principle and provides information of distance (slant range) from the aircraft to the ground station. DME collocated with other navigational instrument (i.e. VHF Omnidirectional Range) allows aircraft to determine its location (longitude, latitude, and altitude) during flying. The Federal Aviation Administration's (FAA) has proposed Alternative Position, Navigation, and Timing (APNT) architecture when Global Navigation Satellite System (GNSS) is unavailable with alternate options of VHF Omnidirectional Range (VOR), DME, TACtical Air Navigation (TACAN) etc. This paper discusses the opportunities and challenges related to use of DME as an alternate source of positioning, navigation and timing, in absence of GNSS services. Also, paper proposes DME-DME network as a reliable APNT with Required Navigation Performance (RNP) to meet future air traffic capacity. This paper is based on the work carried out at Department of Aeronautical Engineering, Military Institute of Science and Technology (MIST), Dhaka, between Jun-2011 to Dec-2012, as the part of the studies in Airborne Radio Navigation System and future trends.

Total Articles- 4

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