Design and Verification of Acoustic Room for Consumer Product Safety Testing
Shulun Mak,
Chiho Li,
Waifan Tang,
Chiwing Lai
Issue:
Volume 5, Issue 3, June 2020
Pages:
50-55
Received:
9 April 2020
Accepted:
22 May 2020
Published:
3 June 2020
Abstract: Sound Producing Toys consists the sound emitting characteristics to attract children’s attention, such as emitting music or simulating animal’s call. The excess sound pressure level (SPL) could damage the human hearing. The international toy safety standards are established to limit the maximum sound pressure level emitted from the product. The Chief Executive of the Hong Kong SAR established the Task Force on Economic Challenges (TFEC) on October 2008. In early 2009, the TFEC has identified six economic areas where Hong Kong enjoys clear advantages. The Six Industries are (i) testing, inspection and certification (TIC), (ii) medical services, (iii) innovation and technology, (iv) cultural and creative industries, (v) environmental industries, and (vi) educational services. The Open University of Hong Kong is offering the undergraduate degree programmes in testing and certification. For the teaching and research purpose, an acoustic room was built to support the areas of sound pressure level measurement in the Open University of Hong Kong. The acoustic room was primarily designed to serve the sound pressure level measurement of the consumer products, including toys and children’s products and gain the Hong Kong Laboratory Accreditation Scheme (HOKLAS) with reference to ISO/IEC 17025. This paper describes the flow of design, consideration of design factors, verification method, applications and limitations of acoustic chamber.
Abstract: Sound Producing Toys consists the sound emitting characteristics to attract children’s attention, such as emitting music or simulating animal’s call. The excess sound pressure level (SPL) could damage the human hearing. The international toy safety standards are established to limit the maximum sound pressure level emitted from the product. The Chi...
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Transient Enhancement of Smart Grid Using SMES Controlled by PID and Fuzzy Logic Control
Ahmed Alshahir,
William Collings,
Richard Molyet,
Raghav Khanna
Issue:
Volume 5, Issue 3, June 2020
Pages:
56-65
Received:
20 May 2020
Accepted:
3 June 2020
Published:
17 June 2020
Abstract: A Smart Grid is an electrical system that is comprised of energy sources, controls, computers and equipment integrated to operate as a unit in the form of an electrical grid to respond to changing power demands. Renewable energy technologies such as a wind turbine are part of this unit. The output power of wind generators experiences dramatic daily fluctuations that are caused by changes in weather patterns. This may adversely affect the power quality and system. To mitigate the effects of these variations, energy storage devices (ESDs) such as superconducting magnetic energy storage system (SMES) can be incorporated into the power system to enhance transient performance and inject or draw electricity to the grid as required. The important role of SMES in the system is to control the system by improving transient stability, which is achieved by use of control technologies. VSC-Based SMES has been used. In this paper, a Proportional-Integral-Derivative (PID) controller and Fuzzy Logic control (FLC) are compared and contrasted. The goal in this paper is to determine which of the two control technologies provides a superior performance while also taking the computational complexity of the simulation into account. Two scenarios in the results have been performed in MATLAB/Simulink 2016b software and the simulation results have validated that FLC is more efficient compared to PID. However, FLC takes approximately 70% more control time.
Abstract: A Smart Grid is an electrical system that is comprised of energy sources, controls, computers and equipment integrated to operate as a unit in the form of an electrical grid to respond to changing power demands. Renewable energy technologies such as a wind turbine are part of this unit. The output power of wind generators experiences dramatic daily...
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Solar Arrays and Battery Power Sources Conceptual Design for Low Earth Orbit Microsatellites
Mohammed Bekhti,
Messaoud Bensaada
Issue:
Volume 5, Issue 3, June 2020
Pages:
66-70
Received:
27 November 2019
Accepted:
31 March 2020
Published:
28 June 2020
Abstract: The power system is a vital subsystem in a spacecraft. As long as the spacecraft has power, it can perform its mission. Almost all other failures can be worked out by ground operations from ground stations but a power loss is very fatal for the spacecraft. In the early years of spaceflight, the power system was also the limiting factor in any mission duration. Many studies show that solar cell power (short-circuit current and open-circuit voltage) are degraded by space environment radiation. The power system is designed such that the end of life (EOL) power is adequate for the mission’s requirements. Beginning of life (BOL) power is set by the estimate of the radiation damage over the spacecraft’s lifetime. It is well known in the literature, the radiation damage to solar cells is caused by high-energy protons from solar flares and from trapped electrons in the Van Allen belt. The purpose of this paper is to investigate the power system design trades involved in the mission analysis of a low earth orbit (LEO) satellite at an altitude of 700 km. Based on the power requirements of the payload and the constant power requirements for the remainder of the spacecraft (platform subsystems), the solar arrays and batteries for the spacecraft will be sized.
Abstract: The power system is a vital subsystem in a spacecraft. As long as the spacecraft has power, it can perform its mission. Almost all other failures can be worked out by ground operations from ground stations but a power loss is very fatal for the spacecraft. In the early years of spaceflight, the power system was also the limiting factor in any missi...
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