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Topic Review
Modular Multilevel Converter Submodules
Voltage-source converter (VSC) HVDC systems based on modular multilevel converters (MMCs) combine the system advantages of fast and independent active and reactive power control, passive network supply, black start capabilities, frequency support and power oscillation damping with power electronics benefits such as scalable design, increased reliability, lower conversion losses and reduced filtering requirements, thus offering a commercially competitive solution. The structure of the SM is an important element of the MMC. This has been the case, where substantial SM topologies have been presented, specifically aimed at extending the functionalities of the MMC, in many cases aligned with niche applications of the converter rather than generic use as a VSC converter.
  • 4.3K
  • 18 Mar 2022
Topic Review
Capillary-Driven Flow Microfluidics
Point-of-care (POC) or near-patient testing allows clinicians to accurately achieve real-time diagnostic results performed at or near to the patient site. The outlook of POC devices is to provide quicker analyses that can lead to well-informed clinical decisions and hence improve the health of patients at the point-of-need. Microfluidics plays an important role in the development of POC devices. However, requirements of handling expertise, pumping systems and complex fluidic controls make the technology unaffordable to the current healthcare systems in the world. In recent years, capillary-driven flow microfluidics has emerged as an attractive microfluidic-based technology to overcome these limitations by offering robust, cost-effective and simple-to-operate devices. The internal wall of the microchannels can be pre-coated with reagents, and by merely dipping the device into the patient sample, the sample can be loaded into the microchannel driven by capillary forces and can be detected via handheld or smartphone-based detectors. The capabilities of capillary-driven flow devices have not been fully exploited in developing POC diagnostics, especially for antimicrobial resistance studies in clinical settings. The purpose of this review is to open up this field of microfluidics to the ever-expanding microfluidic-based scientific community.
  • 4.3K
  • 24 Jul 2020
Topic Review
Power Generation in Sewage-Water Treatment Plants
Sewage-water treatment comprehends primary, secondary, and tertiary steps to produce reusable water after removing sewage contaminants. However, a sewage-water treatment plant is typically a power and energy consumer and produces high volumes of sewage sludge mainly generated in the primary and secondary steps. The use of more efficient anaerobic digestion of sewage water with sewage sludge can produce reasonable flowrates of biogas, which is shown to be a consolidated strategy towards the energy self-sufficiency and economic feasibility of sewage-water treatment plants. Anaerobic digestion can also reduce the carbon footprint of energy sources since the biogas produced can replace fossil fuels for electricity generation. 
  • 4.3K
  • 05 May 2022
Topic Review
Centrifugal Fan
A centrifugal fan is a mechanical device for moving air or other gases in a direction at an angle to the incoming fluid. Centrifugal fans often contain a ducted housing to direct outgoing air in a specific direction or across a heat sink; such a fan is also called a blower, blower fan, biscuit blower, or squirrel-cage fan (because it looks like a hamster wheel). These fans increase the speed and volume of an air stream with the rotating impellers. Centrifugal fans use the kinetic energy of the impellers to increase the volume of the air stream, which in turn moves against the resistance caused by ducts, dampers and other components. Centrifugal fans displace air radially, changing the direction (typically by 90°) of the airflow. They are sturdy, quiet, reliable, and capable of operating over a wide range of conditions. Centrifugal fans are constant-displacement or constant-volume devices, meaning that, at a constant fan speed, a centrifugal fan moves a relatively constant volume of air rather than a constant mass. This means that the air velocity in a system is fixed even though the mass flow rate through the fan is not. Centrifugal fans are not positive-displacement devices and centrifugal fans have certain advantages and disadvantages when contrasted with positive-displacement blowers: centrifugal fans are more efficient, whereas positive-displacement blowers may have a lower capital cost. The centrifugal fan has a drum shape composed of a number of fan blades mounted around a hub. As shown in the animated figure, the hub turns on a driveshaft mounted in bearings in the fan housing. The gas enters from the side of the fan wheel, turns 90 degrees and accelerates due to centrifugal force as it flows over the fan blades and exits the fan housing.
  • 4.3K
  • 23 Oct 2022
Topic Review
Bee Products Treat Polycystic Ovarian Syndrome-Related Infertility
Bee products, including honey, have been utilized since ancient times for nutritional and therapeutic purposes. Other bee products such as bee pollen, royal jelly, and propolis have caught a lot of attention. Being high in antioxidants and bioactive compounds, these products have established their applications in the pharmaceutical field as supplementary or alternative medicines. Polycystic ovarian syndrome (PCOS) as a hormonal disorder in which the ovaries produce an irregular quantity of androgen. Bee products, especially honey, have been used since ancient times as a safer alternative to sugar. Being rich in antioxidants, honey indirectly helps PCOS patients by lowering the risk of oxidative stress, inflammation, and type-2 diabetes.
  • 4.3K
  • 12 Apr 2023
Topic Review
Effective Atomic Number
Effective atomic number has two different meanings: one that is the effective nuclear charge of an atom, and one that calculates the average atomic number for a compound or mixture of materials. Both are abbreviated Zeff.
  • 4.3K
  • 22 Nov 2022
Topic Review
Cairo Declaration on Human Rights in Islam
The Cairo Declaration on Human Rights in Islam (CDHRI) is a declaration of the member states of the Organisation of Islamic Cooperation (OIC) adopted in Cairo, Egypt, on 5 August 1990, (Conference of Foreign Ministers, 9–14 Muharram 1411H in the Islamic calendar) which provides an overview on the Islamic perspective on human rights, and affirms Islamic sharia as its sole source. CDHRI declares its purpose to be "general guidance for Member States [of the OIC] in the field of human rights". This declaration is widely acknowledged as an Islamic response to the United Nations' Universal Declaration of Human Rights (UDHR), adopted in 1948. It guarantees some, but not all, of the UDHR and serves as a living document of human rights guidelines prescribed for all members of the OIC to follow, but restricts them explicitly to the limits set by the sharia. Because of this limit, the CDHRI has been criticized as an attempt to shield OIC member states from international criticism for human rights violations, as well as for failing to guarantee freedom of religion, justifying corporal punishment and allowing discrimination against non-Muslims and women.
  • 4.3K
  • 18 Oct 2022
Topic Review
20% Project
The 20% Project is an initiative where company employees are allocated twenty-percent of their paid work time to pursue personal projects. The objective of the program is to inspire innovation in participating employees and ultimately increase company potential. The 20% Project was influenced by a comparable program, launched in 1948, by manufacturing multinational 3M which required employees to have 15% time: to dedicate up to 15 percent of their paid hours to a personal interest. Technology company Google is credited for popularising the 20% concept, with many of their current services being products of employee pet projects. Some schools have also utilized the principles of the 20% Project to foster creativity and boost productivity.
  • 4.3K
  • 25 Nov 2022
Topic Review
List of Intel Core I7 Microprocessors
The following is a list of Intel Core i7 brand microprocessors. Introduced in 2008, the Core i7 line of microprocessors are intended to be used by high-end users.
  • 4.3K
  • 24 Nov 2022
Topic Review
Powered Hang Glider
A foot-launched powered hang glider (FLPHG), also called powered harness, nanolight, or hangmotor, is a powered hang glider harness with a motor and propeller in pusher configuration. An ordinary hang glider is used for its wing and control frame, and the pilot can foot-launch from a hill or from flat ground, needing a length of about a football field to get airborne, or much less if there is an oncoming breeze and no obstacles.
  • 4.3K
  • 04 Nov 2022
Topic Review
Agriculture 5.0 and Remote Sensing
Constant industrial innovation has made it possible that 2021 has been officially marked by the European Commission as the beginning of the era of “Industry 5.0”. In this 5th industrial revolution, RS has the potential of being one of the most important technologies for today’s agriculture. RS sprouted in the 19th century (specifically in 1858) through the use of air balloons for aerial observations. At present, it occupies a central position in precision agriculture (PA) and soil studies. It is also important to mention some of the interchangeable terms most commonly used include “precision farming”, “precision approach”, “remote sensing”, “digital farming”, “information intensive agriculture”, “smart agriculture”, “variable rate technology (VRT)”, “global navigation satellite system (GNSS) agriculture”, “farming by inch”, “site specific crop management”, “digital agriculture”, “agriculture 5.0”, etc. RS is a vast term that covers various technological systems, such as satellites, RPAs, GNSS, geographic information systems (GIS), big data analysis, the Internet of Things (IoT), the Internet of Everything (IoE), cloud computing, wireless sensors technologies (WST), decision support systems (DSS), and autonomous robots.
  • 4.3K
  • 14 Sep 2021
Topic Review
Weather Radar
The history of Weather Radar (abbreviation of RAdio Detecting And Ranging) begins during World War II, when military radar operators noticed extraneous echoes showing up on their display. David Atlas was one of the pioneers of radar meteorology, along with John Stewart Marshall, Walter Palmer and Richard Doviak. Weather radars send pulses of electromagnetic energy into the atmosphere, a microsecond of long microwave radiation to identify the presence of hydrometeors.
  • 4.3K
  • 17 Feb 2022
Topic Review Peer Reviewed
Benefits of Badminton for Preventing Cognitive Decline and Dementia
Badminton is one of the most popular racket sports played by all age groups worldwide. Anyone can practice and play badminton as a leisure or competitive sport, regardless of age, experience, or skill level. It does not require physical contact among players or expensive equipment. Compared with closed-skill exercises (e.g., running and swimming), open-skill exercises (e.g., badminton and table tennis) have been reported to significantly improve cognitive function and prevent cognitive decline. This mini review aimed to investigate the findings related to badminton intervention for cognitive function, with attention to the modifiable risk factors of dementia in adults. Additionally, we outlined the characteristics of badminton’s physical demands. This narrative review encompassed studies reported from 2013 to 2023 from multiple databases, including PubMed and Google Scholar. Keywords such as “badminton”, “dementia”, “cognitive function”, “physical activity”, and “depression” were used to identify relevant articles. Various studies, including randomized controlled trials, cohort studies, and case–control studies, were selected to provide a comprehensive overview of badminton intervention. Quantitative data analysis suggests that at a cognitive level, high-intensity badminton can enhance cognitive function with at least 10 min of play once weekly or 20 min of play once weekly on average, whereas moderate-intensity badminton can be effective when played for at least 30 min once weekly or 35 min twice weekly on average. For modifiable risk factors, recreational badminton for about 3 h weekly could effectively manage blood pressure. For body fat percentage and fasting serum glucose levels, recreational badminton for about 10 h weekly exerted positive effects. For depressive states, a moderate-intensity badminton program for 100 min weekly was effective. For lipid profiles associated with dementia occurrence, prolonged badminton intervention for more than 3 months may be beneficial. The characteristics presented here indicate that intervention with regular badminton exercise could effectively improve cognitive function and prevent cognitive decline in older adults.
  • 4.3K
  • 18 Jun 2024
Topic Review
Dry Permanent Magnetic Separator
Dry magnetic separation is a technology that sorts magnetic minerals from gangue using air as the medium instead of water. When raw ore is fed to the magnetic separator, the magnetic particles are subjected to magnetic force due to the nonuniform magnetic field. When the magnetic force exceeds the competitive force (i.e., gravity and fluid drag force), the particles are captured on or attracted towards the surface of the drum and consequently enter the magnetic product. Meanwhile, the gangue or poor intergrowth particles are not subjected to magnetic force and are separated into the non-magnetic product under the action of competitive force. In other words, magnetic minerals and gangue have different trajectories in a magnetic separator, thereby achieving the purpose of separation. Dry magnetic separation has been recently adopted by plants to cope with cost and environmental pressures.
  • 4.3K
  • 24 Oct 2022
Topic Review
The Biological Effects of Retinoids in the Skin
In the early 20th century, retinol (commonly known as vitamin A) was isolated and characterized as an essential nutrient for human health. Retinoids are natural and synthetic vitamin A derivatives that are effective for the prevention and the treatment of non-melanoma skin cancers. The effects of retinoid signaling on skin physiology have been studied extensively.
  • 4.3K
  • 01 Nov 2022
Topic Review
World View
A world view or worldview is the fundamental cognitive orientation of an individual or society encompassing the whole of the individual's or society's knowledge and point of view. A world view can include natural philosophy; fundamental, existential, and normative postulates; or themes, values, emotions, and ethics. The term is a calque of the German word Weltanschauung [ˈvɛltʔanˌʃaʊ.ʊŋ] (listen), composed of Welt ('world') and Anschauung ('view' or 'outlook'). The German word is also used in English. It is a concept fundamental to German philosophy and epistemology and refers to a wide world perception. Additionally, it refers to the framework of ideas and beliefs forming a global description through which an individual, group or culture watches and interprets the world and interacts with it. Worldview remains a confused and confusing concept in English, used very differently by linguists and sociologists. It is for this reason that James W. Underhill suggests five subcategories: world-perceiving, world-conceiving, cultural mindset, personal world, and perspective. Worldviews are often taken to operate at a conscious level, directly accessible to articulation and discussion, as opposed to existing at a deeper, pre-conscious level, such as the idea of "ground" in Gestalt psychology and media analysis. However, core worldview beliefs are often deeply rooted, and so are only rarely reflected on by individuals, and are brought to the surface only in moments of crises of faith.
  • 4.3K
  • 26 Oct 2022
Topic Review Peer Reviewed
Alphonse II of Aragon (1164–1196)
Alphonse II King of Aragon (1164–1196). He was the first king of the Crown of Aragon and son of the Queen Petronila of Aragon (1157–1164) and the count of Barcelona, Ramon Berenguer IV (1137–1162). Aware of the new political reality that he embodied as King of Aragon and Count of Barcelona, Alphonse II made significant changes to his iconography. Among the most important of these is the binomial that he incorporated to his pendent seals; that is, a portrayal of Alphonse enthroned as king on the obverse and Alphonse as count and mounted on a horse on the reverse. As a known bibliophile and as a result of his desire to reorganise his chancellery following the union of various political entities, he ordered the compilation of the Liber Feudorum Maior, the folios of which demonstrate his potestas regia through their lavish iconography. He was no less innovative in his coinage, on which he included, for the first time, the image of his head wearing the crown.
  • 4.3K
  • 13 Apr 2022
Topic Review
Tranditional Use and Nutritional Value of Lansium domesticum
Lansium domesticum (Langsat, Meliaceae) is a tropical fruit mainly found in Southeast Asian countries, particularly in Thailand, Malaysia, Indonesia, and the Philippines.
  • 4.3K
  • 21 Apr 2022
Topic Review
Cocaine
Cocaine is one of the most consumed stimulants throughout the world, as official sources report. It is a naturally occurring sympathomimetic tropane alkaloid derived from the leaves of Erythroxylon coca, which has been used by South American locals for millennia. Cocaine can usually be found in two forms, cocaine hydrochloride, a white powder, or ‘crack’ cocaine, the free base. 
  • 4.3K
  • 27 Apr 2022
Topic Review
Structure from Motion
Structure from Motion (SfM) is a photogrammetric range imaging technique for estimating three-dimensional structures from two-dimensional image sequences that may be coupled with local motion signals. It is studied in the fields of computer vision and visual perception. In biological vision, SfM refers to the phenomenon by which humans (and other living creatures) can recover 3D structure from the projected 2D (retinal) motion field of a moving object or scene.
  • 4.3K
  • 06 Oct 2022
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