14,537 research outputs found
The ATLAS SCT grounding and shielding concept and implementation
This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper
IMPROVEMENT OF GROUNDING SYSTEM TO REDUCE THE EFFECT OF LIGHTNING OVERVOLTAGE BY BONDING METHOD
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āļāļēāļāđāļĢāļāļāļąāļāđāļāļīāļāļāđāļēāļāđāļē āđāļāļĒāđāļāđāļ§āļīāļāļĩāļāļēāļĢāļāļĢāļ°āļŠāļēāļāļĻāļąāļāļĒāđāļāļĩāđāđāļŦāļĄāļēāļ°āļŠāļĄ āđāļŦāđāļāļąāļāļāļēāļāļēāļĢāļŠāļāļēāļāļĩāļŠāđāļāļ§āļīāļāļĒāļļāđāļĨāļ°āđāļāļĢāļ·āđāļāļāļāđāļ§āļĒ
āđāļāļīāļāļāļēāļāļēāļĻ āļĻāļđāļāļĒāđāļāļ§āļāļāļļāļĄāļāļēāļĢāļāļīāļ āļāļĩāđāđāļāđāļĢāļąāļāļāļĨāļāļĢāļ°āļāļāļāļēāļāđāļĢāļāļāļąāļāđāļāļīāļāļāđāļēāļāđāļē āļŠāđāļāļāļĨāđāļŦāđāļĢāļ°āļāļāđāļāļāđāļēāđāļĨāļ°āļāļļāļāļāļĢāļāđ
āđāļāļĢāļ·āđāļāļāļāđāļ§āļĒāđāļāļīāļāļāļēāļāļēāļĻāđāļāļīāļāļāļ§āļēāļĄāđāļŠāļĩāļĒāļŦāļēāļĒ
āđāļāļĒāļāļģāļāļēāļĢāļŠāļģāļĢāļ§āļāļāļ·āđāļāļāļĩāđāļāļēāļāļēāļĢ, āļĢāļ°āļāļāļāļēāļĢāļāđāļāļĨāļāļāļīāļāļĢāļ§āļĄāļāļąāđāļāļĢāļ°āļāļāļĢāļēāļāļŠāļēāļĒāļāļīāļāļāļāļāļāļēāļāļēāļĢ āđāļĨāļ°
āļŠāļēāļĒāļŠāļąāļāļāļēāļāļāļĩāđāļĄāļĩāļāļēāļĢāđāļāļ·āđāļāļĄāļāđāļāļĢāļ°āļŦāļ§āđāļēāļāļāļēāļāļēāļĢāļāļąāļāļāļļāļāļāļĢāļāđāđāļāļĢāļ·āđāļāļāļāđāļ§āļĒāđāļāļīāļāļāļēāļāļēāļĻ āđāļĨāļ°āļāļģāļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđ
āļāļĪāļāļīāļāļĢāļĢāļĄāļāļēāļĢāđāļāļīāļāđāļĢāļāļāļąāļāļāļąāđāļ§āļāļĢāļđāđāļāļĩāđāļĄāļĩāļāļĨāļāļēāļāļāđāļēāļāļ§āļēāļĄāļāđāļēāļāļāļēāļāđāļĨāļ°āļāđāļēāļāļīāļĄāļāļĩāđāļāļāļāđāļāļāļāļĢāļēāļāļŠāļēāļĒāļāļīāļ āđāļāļ·āđāļ
āļāļģāđāļāđāļāđāđāļāļāļēāļĢāļāļĢāļąāļāļāļĢāļļāļāļĢāļ°āļāļāļĢāļēāļāļŠāļēāļĒāļāļīāļ āđāļĨāļ°āļāļīāļāļāļąāđāļāļāļļāļāļāļĢāļāđāļāđāļāļāļāļąāļāđāļŠāļīāļĢāđāļ āđāļāļĒāļāļģāļāļēāļĢāļāļĢāļąāļāļāļĢāļļāļāļāļēāļĄ
āļĄāļēāļāļĢāļāļēāļ IEC āđāļĨāļ°āļĄāļēāļāļĢāļāļēāļāļāđāļāļāļāļąāļāļāđāļēāļāđāļēāļāļāļāļ§āļīāļĻāļ§āļāļĢāļĢāļĄāļŠāļāļēāļāđāļŦāđāļāļāļĢāļ°āđāļāļĻāđāļāļĒ
āļāđāļāļāļāļģāļāļēāļĢāļāļĢāļąāļāļāļĢāļļāļāļĢāļ°āļāļāļāļēāļĢāļāđāļāļĨāļāļāļīāļāđāļĨāļ°āļĢāļ°āļāļāļĢāļēāļāļŠāļēāļĒāļāļīāļ āļāļāļ§āđāļēāđāļĄāđāļĄāļĩāļāļēāļĢāļāļĢāļ°āļŠāļēāļāđāļŦāđāļĻāļąāļāļĒāđ
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āļĄāļēāļāļĢāļāļēāļ āļāļ·āļ 4.7, 5.62 āđāļĨāļ° 35.9 āđāļāļŦāđāļĄ āđāļāļĒāļĄāļĩāļāđāļēāļāļ§āļēāļĄāđāļŦāļāļĩāđāļĒāļ§āļāļģāļĢāļ§āļĄāļāļąāđāļāļĢāļ°āļāļāļāļĩāđ 9.235 āđāļĄāđāļāļĢāđāļŪāļāļĢāļĩāđ āđāļĄāļ·āđāļ
āļāļģāļāļēāļĢāļāļĢāļąāļāļāļĢāļļāļāļāļēāļĢāļāđāļāļĨāļāļāļīāļāđāļĨāļ°āļĢāļ°āļāļāļĢāļēāļāļŠāļēāļĒāļāļīāļ āđāļĨāļ°āļāļīāļāļāļąāđāļāļāļļāļāļāļĢāļāđāļāđāļāļāļāļąāļāđāļŠāļīāļĢāđāļāļāļĩāđāļĢāļ°āļāļāđāļāļāđāļēāļ āļēāļĒāđāļ
āļāļēāļāļēāļĢ āļāļĨāļāļēāļāļāļēāļĢāļāļĢāļąāļāļāļĢāļļāļāļāļģāđāļŦāđāļĢāļ°āļāļāļĢāļēāļāļŠāļēāļĒāļāļīāļāđāļĨāļ°āļāļļāļāļāđāļāļĨāļāļāļīāļ āļāļĢāļ°āļŠāļēāļāļĻāļąāļāļĒāđāļāļķāļāļāļąāļāđāļāļĒāļŠāļĄāļāļđāļĢāļāđ
āļŠāđāļāļāļĨāđāļŦāđāļāđāļēāļāļ§āļēāļĄāļāđāļēāļāļāļēāļāļāļīāļāļĨāļāļĨāļāđāļŦāļĨāļ·āļ 2.44 āđāļāļŦāđāļĄ āđāļĨāļ°āļāđāļēāļāļ§āļēāļĄāđāļŦāļāļĩāđāļĒāļ§āļāļģāļĢāļ§āļĄāļāļāļāļĢāļ°āļāļāļĨāļāļĨāļāđāļŦāļĨāļ·āļ
6.595 āđāļĄāđāļāļĢāđāļŪāļāļĢāļĩāđ āđāļĄāļ·āđāļāļāļģāļāļēāļĢāļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāļāļĪāļāļīāļāļĢāļĢāļĄāļāļēāļĢāđāļāļīāļāđāļĢāļāļāļąāļāļāļąāđāļ§āļāļĢāļđāđāļāļĩāđāļāļāļāļĢāđāļāļĄāļĢāļēāļāļŠāļēāļĒāļāļīāļāļāđāļāļāđāļĨāļ°
āļŦāļĨāļąāļāļāļēāļĢāļāļĢāļąāļāļāļĢāļļāļ āļāļĩāđāļāđāļēāļāļĢāļ°āđāļŠāļāđāļēāļāđāļēāļāļĢāļ āļāļĩāđāļĄāļĩāļāļ§āļēāļĄāļāļąāļāļāļāļāļāļĢāļ°āđāļŠāļŦāļāđāļēāļāļĨāļ·āđāļāđāļāļāļāđāļēāļāļāļąāļāđāļāļāļāļ§āđāļēāđāļĢāļāļāļąāļ
āļāļāļāļĢāđāļāļĄāļĢāļēāļāļŠāļēāļĒāļāļīāļāļĄāļĩāļāđāļēāļĨāļāļĨāļ āļāļķāđāļāļŠāļēāļĄāļēāļĢāļāļĨāļāļāļ§āļēāļĄāđāļŠāļĩāđāļĒāļāļāđāļāļāļ§āļēāļĄāđāļĄāđāļāļĨāļāļāļ āļąāļĒāļāļāļāļĢāļ°āļāļāļāļēāļĢāđāļŦāđāļāļĢāļīāļāļēāļĢ
āļāļĢāļēāļāļĢāļāļēāļāļāļēāļāļēāļĻ āļĢāļ°āļāļāļāļēāļĢāļŠāļ·āđāļāļŠāļēāļĢāļāļēāļĢāļāļīāļ āļĢāļ§āļĄāļāļąāđāļāļāļ§āļēāļĄāđāļŠāļĩāļĒāļŦāļēāļĒāļāđāļāļāļĩāļ§āļīāļāđāļĨāļ°āļāļĢāļąāļāļĒāđāļŠāļīāļāđāļāđThis thesis presents the improvement of grounding and earth termination system. To reduce the
effect of lightning overvoltage, the suitable bonding method with Non-Direction Beacon (NDB) station
building is proposed. The lightning overvoltage can cause of electrical equipment damage.
The research methods were proposed as follows : first, the surveying of the building area,
existing grounding and earth termination system, and coaxial cables which are connected to NDB
equipment. Next, the analysis of transient overvoltage behavior is performed to investigate the affect of
resistance and inductance of grounding system. Finally, the improvement has been done by
modification of the grounding system and installation of the surge protection device (SPD) by referring
the IEC 62305 standard and EIT standard.
Before the improvement of grounding system, it is dearly seen that the grounding resistance of
each points is different due to lack of equipotential bonding. Thus, the values of grounding system are
strongly deviated e.g., 4.7 ÎĐ, 5.62 ÎĐ and 35.9 ÎĐ, and the total inductance value is 9.235 ΞH. After
grounding system has been improved and SPD has been installed, the results of grounding system
improvement and earth termination system are shown that the grounding resistance is reduced to 2.44
ÎĐ and total inductance value is decreased to 6.595 ΞH. The analysis of grounding system behavior due
to transient overvoltage by ATP/EMTP program. The current source in the equivalent circuit is
modeled by using the direct stroke current with different front time slope. It can be found that voltage
drop across earth termination has been reduced. The results of grounding system improvement can
reduce the risks of damage to person, equipments and Aeronautical radio system
Assessment and control of spacecraft electromagnetic interference
Design criteria are presented to provide guidance in assessing electromagnetic interference from onboard sources and establishing requisite control in spacecraft design, development, and testing. A comprehensive state-of-the-art review is given which covers flight experience, sources and transmission of electromagnetic interference, susceptible equipment, design procedure, control techniques, and test methods
Electromagnetic Compatibility Considerations for International Space Station Payload Developers
The International Space Station (ISS) is a laboratory for scientific research, innovative technology development, and global education. The ISS provides a number of facilities and platforms for payload developers and investigators to conduct biological, microgravity, and Earth and space observation science, as well as for performing technology development. Due to the unique nature of the ISS vehicle and its electrical power and data systems, achieving electromagnetic compatibility (EMC) with the vehicle requires special considerations by the payload developer. The ISS electromagnetic interference (EMI) requirements and test methods are based on MIL-STD-461, Electromagnetic Emissions and Susceptibility Requirements for the Control of Electromagnetic Interference, Revision C, and MIL-STD-462, Electromagnetic Interference Characteristics, Measurement of, respectively. The low source impedance of the test setup requires special considerations when designing or selecting EMI power filters and switched mode power supplies. Many filters, suited for later revisions of MIL-STD-461, will result in non-compliant designs. ISS electrical power system power quality requirements, imposed to protect the stability of the system, can also affect EMI filter design. The selection and use of commercial-off-the-shelf (COTS) equipment for ISS applications requires special considerations to meet both EMC and crew safety requirements. Furthermore, the ISS environment can provide unique immunity challenges; if the payload developer ignores these challenges, the result is a possible loss of science or impact to technology demonstration. The ISS provides a unique opportunity for the science and technology development community. However, in order to be successful, the payload developer must incorporate special EMC considerations, many of which will be presented
How to protect a wind turbine from lightning
Techniques for reducing the chances of lightning damage to wind turbines are discussed. The methods of providing a ground for a lightning strike are discussed. Then details are given on ways to protect electronic systems, generating and power equipment, blades, and mechanical components from direct and nearby lightning strikes
Aircraft electromagnetic compatibility
Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting
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