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Topic Review
Precision Machining by Dicing Blades
Diamond dicing blades are profound cutting tools that find their applications in semiconductor back-end packaging and assembly processes. To fully appreciate the benefits of the dicing blade technique for precision machining, a deeper understanding is required.
  • 891
  • 22 Feb 2023
Topic Review
Switchgear
In an electric power system, switchgear is the combination of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream. This type of equipment is directly linked to the reliability of the electricity supply. The earliest central power stations used simple open knife switches, mounted on insulating panels of marble or asbestos. Power levels and voltages rapidly escalated, making opening manually operated switches too dangerous for anything other than isolation of a de-energized circuit. Oil-filled equipment allowed arc energy to be contained and safely controlled. By the early 20th century, a switchgear line-up would be a metal-enclosed structure with electrically operated switching elements, using oil circuit breakers. Today, oil-filled equipment has largely been replaced by air-blast, vacuum, or SF6 equipment, allowing large currents and power levels to be safely controlled by automatic equipment. High-voltage switchgear was invented at the end of the 19th century for operating motors and other electric machines. The technology has been improved over time and can now be used with voltages up to 1,100 kV. Typically, switchgear in substations are located on both the high- and low-voltage sides of large power transformers. The switchgear on the low-voltage side of the transformers may be located in a building, with medium-voltage circuit breakers for distribution circuits, along with metering, control, and protection equipment. For industrial applications, a transformer and switchgear line-up may be combined in one housing, called a unitized substation (USS).
  • 891
  • 21 Nov 2022
Topic Review
Healthy Building in China
Healthy buildings are a deep-level development of green buildings, which can effectively help relieve stress and improve occupants’ physical and mental health. In addition, they are is likely to play an important role in preventing the spread of respiratory infectious diseases. Therefore, healthy buildings have attracted worldwide attention. The development of healthy buildings in China is quite different from that of other countries and has its own characteristics with many factors, such as project implementation, environmental pollution, and social issues affecting healthy buildings development in China. 
  • 890
  • 28 Mar 2022
Topic Review
WiMAX
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMAX Forum was formed in June 2001 to promote conformity and interoperability, including the definition of system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL". IEEE 802.16m or WirelessMAN-Advanced was a candidate for 4G, in competition with the LTE Advanced standard. WiMAX was initially designed to provide 30 to 40 megabit-per-second data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations. WiMAX release 2.1, popularly branded as WiMAX 2+, is a backwards-compatible transition from previous WiMAX generations. It is compatible and interoperable with TD-LTE.
  • 890
  • 31 Oct 2022
Topic Review
Pretreatment of Hemp Biomass
It is widely accepted that fossil fuel resources emit greenhouse gases (GHG), which are the leading cause for the climate crisis, with the manufacturing, energy, and agriculture sectors as main contributors. The agricultural sector is composed of diversified and potential mobilizable sources of waste which can become an attractive alternative to fossil fuels for energy production, and thus sequester and use carbon. Therefore, a paradigm shift towards more sustainable energy alternatives, efficient waste management, and new technologies is necessary. One good solution is the energetic valorization of lignocellulosic biomass (LCB) which can also originate from agricultural wastes. The biomass consists of cellulose, hemicellulose, and lignin, which are sources of fermentable sugars that can be used for bioethanol production. However, the recovery of sugars requires the pretreatment of LCB before enzymatic hydrolysis, due to its inaccessible molecular structure. Therefore, pretreatment is required to enhance enzyme accessibility as well as bioethanol production. Raw hemp biomass consists of 35-51% cellulose (dry basis, db), 13–28% hemicellulose (db), and 12-22% lignin (db). Chemical pretreatment, more specifically alkaline pretreatment, is the most commonly used for hemp biomass.
  • 890
  • 07 Nov 2022
Topic Review
Piezoelectric MEMS Laterally Vibrating Resonators
Piezoelectric MEMS Laterally Vibrating Resonators (LVRs), which belong to one type of micromachined resonators that uses piezoelectric transduction, are characterized by dominant mechanical vibration in the lateral direction (within the plane of the device). In piezoelectric MEMS LVRs, the electric field is mainly applied across the thickness of the piezoelectric film to generate a lateral strain within the plane of the device with suspended free edges. Due to the lithographically definable resonant frequency, piezoelectric LVRs feature wide operation frequency coverage (from tens of MHz to several GHz) and provide a pathway towards realizing a multi-frequency integrated solution on a single chip. Depending on the structure of resonators, piezoelectric MEMS LVRs can be categorized into two types. The first type of LVRs consists of a piezoelectric film, both as the transducer and acoustic cavity. The second type of LVRs uses the thin piezoelectric film as a transducer only while having most of the acoustic energy propagating in the underlying thicker substrate. Such resonators are usually referred to as thin-film piezoelectric-on-substrate (TPoS) resonators. Typical applications of piezoelectric MEMS LVRs include resonant sensors, oscillators and RF filters.
  • 890
  • 14 Sep 2020
Topic Review
AKG
AKG Acoustics (originally Akustische und Kino-Geräte Gesellschaft m.b.H., English: Acoustic and Cinema Equipment L.L.C.) is an acoustics engineering and manufacturing company. It was founded in 1947 by Dr. Rudolf Görike and Ernest Plass in Vienna, Austria. It is a part of Harman International Industries, a subsidiary of Samsung Electronics. The products currently marketed under the AKG brand mostly consist of microphones, headphones, wireless audio systems and related accessories for professional and consumer markets.
  • 889
  • 20 Oct 2022
Topic Review
Catalyst Supports for Renewable Diesel Production
High energy demand from the market due to the rapid increment of the human population worldwide has urged society to explore alternatives to replace non-renewable energy. Renewable diesel produced from biomass could be the next potential energy source for its high stability, long-term storage, and comparable performance with diesel fuels. In producing renewable diesel, the application of catalyst is essential, and the catalyst support is synthesized with the catalyst to enhance the reaction rate and catalytic properties. The application of the supported catalyst in increasing the selectivity and yield of renewable diesel is significant, in which the catalytic properties depend on the interaction between catalyst and catalyst support. The supported catalyst as a favorable substance to assist in enhancing renewable diesel yield could lead to a sustainable and greener future for the biofuel industry in Malaysia.
  • 889
  • 29 Apr 2022
Topic Review
Billing (Performing Arts)
Billing is a performing arts term used in referring to the order and other aspects of how credits are presented for plays, films, television, or other creative works. Information given in billing usually consists of the companies, actors, directors, producers, and other crew members.
  • 888
  • 14 Oct 2022
Topic Review
MIMO Radars
This entry reports a thorough overview on the last developments concerning the vital sign detection and the human localization employing the multiple-input-multiple-output (MIMO) technology. The wireless motion and vital sign detection represents an outstanding research area aimed at monitoring the health conditions of human subjects and at detecting their presence in different environments with minimal concern. MIMO radars exhibit several interesting advantages over conventional single-input-single-output architectures mainly related to their angle detection capabilities and enhanced signal-to-noise ratio. This paper describes the main features and details the operating principles of MIMO technology. Thereafter, it summarizes the state-of-the-art of the available solutions with the purpose of fueling the research activities on this hot topic.
  • 888
  • 17 Sep 2020
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