Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Biography
Sarkes Tarzian
Sarkes Tarzian (October 5, 1900 – November 17, 1987) was an Ottoman-born United States engineer, inventor, and broadcaster. He was ethnic Armenian born in the Ottoman Empire. He and his family immigrated to Philadelphia, Pennsylvania, United States in 1907, following their persecution by Ottoman Turks.[1] "His father escaped to America from the Turkish massacres of Armenians, and got a job as
  • 519
  • 26 Dec 2022
Topic Review
Plasma-Enhanced Chemical Vapor Deposition
Plasma-enhanced chemical vapor deposition (PECVD) is a chemical vapor deposition process used to deposit thin films from a gas state (vapor) to a solid state on a substrate. Chemical reactions are involved in the process, which occur after creation of a plasma of the reacting gases. The plasma is generally created by radio frequency (RF) (alternating current (AC)) frequency or direct current (DC) discharge between two electrodes, the space between which is filled with the reacting gases.
  • 515
  • 18 Nov 2022
Topic Review
Navigational Aid
A navigational aid (navaid), also known as aid to navigation (ATON), is any sort of marker which aids the traveler in navigation, usually nautical or aviation travel. Common types of such aids include lighthouses, buoys, fog signals, and day beacons.
  • 512
  • 24 Oct 2022
Topic Review
Gabor Filters
The use of Gabor filters in image processing has been well-established, and these filters are recognized for their exceptional feature extraction capabilities. These filters are usually applied through convolution.
  • 512
  • 19 Dec 2023
Topic Review
Digital Enhanced Cordless Telecommunications
Digital Enhanced Cordless Telecommunications (Digital European Cordless Telecommunications), usually known by the acronym DECT, is a standard primarily used for creating cordless telephone systems. It originated in Europe, where it is the universal standard, replacing earlier cordless phone standards, such as 900 MHz CT1 and CT2. Beyond Europe, it has been adopted by Australia , and most countries in Asia and South America. North American adoption was delayed by United States radio frequency regulations. This forced development of a variation of DECT, called DECT 6.0, using a slightly different frequency range which makes these units incompatible with systems intended for use in other areas, even from the same manufacturer. DECT has almost universally replaced other standards in most countries where it is used, with the exception of North America. DECT was originally intended for fast roaming between networked base stations and the first DECT product was Net3 wireless LAN. However, its most popular application is single-cell cordless phones connected to traditional analog telephone, primarily in home and small office systems, though gateways with multi-cell DECT and/or DECT repeaters are also available in many private branch exchange (PBX) systems for medium and large businesses produced by Panasonic, Mitel, Gigaset, Snom, BT Business, Spectralink, and RTX Telecom. DECT can also be used for purposes other than cordless phones, such as baby monitors and industrial sensors. The ULE Alliance's DECT ULE and its HAN FUN protocol are variants tailored for home security, automation, and the internet of things (IoT). The DECT standard includes the generic access profile (GAP), a common interoperability profile for simple telephone capabilities, which most manufacturers implement. GAP-conformance enables DECT handsets and bases from different manufacturers to interoperate at the most basic level of functionality, that of making and receiving calls. New Generation DECT (NG-DECT) standard, marketed as CAT-iq by the DECT Forum, provides a common set of advanced capabilities for handsets and base stations. CAT-iq allows interchangeability across IP-DECT base stations and handsets from different manufacturers, while maintaining backward-compatibility with GAP equipment. It also requires mandatory support for wideband audio.
  • 511
  • 31 Oct 2022
Biography
Gordon L. Park
Gordon Lesley Park (June 29, 1937 – March 11, 2010) was a petroleum engineer and geologist for the Chevron Oil Company, who served from 1993 to 1996 as a Republican member of the Wyoming House of Representatives from District 49 in Uinta County. Park was born to Harold Gordon Park and the former Iva Hazel Edwards (born 1917) in Lexington in Cleveland County in central Oklahoma. He was reare
  • 511
  • 26 Dec 2022
Biography
Robert S. Williamson
Robert Stockton Williamson (January 21, 1825 – November 10, 1882) was an American soldier and engineer, noted for conducting surveys for the transcontinental railroad in California and Oregon. Inducted into the Army Corps of Engineers in 1861, he had a distinguished record serving in the American Civil War, winning two brevet promotions. When the US Army Corps of Engineers established its San
  • 510
  • 10 Nov 2022
Biography
Richard Hieb
Richard James Hieb (born September 21, 1955 in Jamestown, North Dakota) is a former NASA astronaut and a veteran of three space shuttle missions. He was a mission specialist on STS-39 and STS-49, and was a payload commander on STS-65. After leaving NASA he worked at AlliedSignal and Orbital before spending 14 years as an executive at Lockheed Martin. He is currently a faculty member in the Unive
  • 510
  • 07 Dec 2022
Topic Review
SODAR
SODAR (SOnic Detection And Ranging), also written as sodar, is a meteorological instrument used as a wind profiler to measure the scattering of sound waves by atmospheric turbulence. SODAR systems are used to measure wind speed at various heights above the ground, and the thermodynamic structure of the lower layer of the atmosphere. Sodar systems are in fact nothing more than sonar systems used in the air rather than in water; more specifically, since they operate using the Doppler effect with a multi-beam configuration to determine wind speed, they are the exact in-air equivalent to a subclass of sonar systems known as acoustic Doppler current profilers. Other names used for sodar systems include sounder, echosounder and acoustic radar.
  • 509
  • 29 Sep 2022
Topic Review
List of Tram Track Gauges
A list of tram track gauges is given below.
  • 509
  • 14 Nov 2022
Topic Review
Authentic Learning
In education, authentic learning is an instructional approach that allows students to explore, discuss, and meaningfully construct concepts and relationships in contexts that involve real-world problems and projects that are relevant to the learner. It refers to a "wide variety of educational and instructional techniques focused on connecting what students are taught in school to real-world issues, problems, and applications. The basic idea is that students are more likely to be interested in what they are learning, more motivated to learn new concepts and skills, and better prepared to succeed in college, careers, and adulthood if what they are learning mirrors real-life contexts, equips them with practical and useful skills, and addresses topics that are relevant and applicable to their lives outside of school." Authentic instruction will take on a much different form than traditional teaching methods. In the traditional classroom, students take a passive role in the learning process. Knowledge is considered to be a collection of facts and procedures that are transmitted from the teacher to the student. In this view, the goal of education is to possess a large collection of these facts and procedures. Authentic learning, on the other hand, takes a constructivist approach, in which learning is an active process. Teachers provide opportunities for students to construct their own knowledge through engaging in self-directed inquiry, problem solving, critical thinking, and reflections in real-world contexts. This knowledge construction is heavily influenced by the student's prior knowledge and experiences, as well as by the characteristics that shape the learning environment, such as values, expectations, rewards, and sanctions. Education is more student-centered. Students no longer simply memorize facts in abstract and artificial situations, but they experience and apply information in ways that are grounded in reality.
  • 508
  • 14 Oct 2022
Topic Review
Design Components for Electrospun Vascular Prosthesis
The design parameters for electrospun vascular grafts can be divided into two categories: the constructional parameters, which involve fiber diameter, pore size, porosity, fiber orientation, wall thickness, the number of layers, and material selection. The scaffold’s configuration and material choice are both essential because they have a significant impact on mechanical and biological characteristics, including compliance, tensile strength, burst pressure, blood permeability, and suturability, as well as biological processes such as cell phenotype, extracellular matrix (ECM) formation, and cell diffusion.
  • 508
  • 26 Oct 2022
Topic Review
Liver Support Systems
Liver support systems are therapeutic devices to assist in performing the functions of the liver in persons with liver damage. The primary functions of the liver include removing toxic substances from the blood, manufacturing blood proteins, storing energy in the form of glycogen, and secreting bile. The hepatocytes that perform these tasks can be killed or impaired by disease, resulting in hepatic insufficiency. A sudden onset of life-threatening hepatic insufficiency is known as acute liver failure (ALF). In hyperacute and acute liver failure the clinical picture develops rapidly with progressive encephalopathy and multiorgan dysfunction such as hyperdynamic circulation, coagulopathy, acute kidney injury and respiratory insufficiency, severe metabolic alterations and cerebral edema that can lead to brain death. In these cases the mortality without liver transplantation (LTx) ranges between 40-80%. LTx is the only effective treatment for these patients although it requires a precise indication and timing to achieve good results. Nevertheless, due to the scarcity of organs to carry out liver transplantations, it is estimated that one third of patients with ALF die while waiting to be transplanted. On the other hand, a patient with a chronic hepatic disease can suffer an acute decompensation of liver function following a precipitating event such as variceal bleeding, sepsis and excessive alcohol intake among others that can lead to a condition referred to as acute-on-chronic liver failure (ACLF). Both types of hepatic insufficiency, ALF and ACLF, can potentially be reversible and liver functionality can return to a level similar to that prior to the insult or precipitating event. LTx is the only treatment that has shown an improvement in the prognosis and survival with most severe cases of ALF. Nevertheless, cost and donor scarcity have prompted researchers to look for new supportive treatments that can act as “bridge” to the transplant procedure. By stabilizing the patient's clinical state, or by creating the right conditions that could allow the recovery of native liver functions, both detoxification and synthesis can improve, after an episode of ALF or ACLF. Basically, three different types of supportive therapies have been developed: bio-artificial, artificial and hybrid liver support systems (Table 2). Bio-artificial liver support systems are experimental extracorporeal devices that use living cell lines to provide detoxification and synthesis support to the failing liver. Bio-artificial liver (BAL) Hepatassist 2000 uses porcine hepatocytes11 whereas ELAD system employs hepatocytes derived from human hepatoblastoma C3A cell lines.9, Both techniques can produce, in fulminant hepatic failure (FHF), an improvement of hepatic encephalopathy grade and biochemical parameters. Nevertheless, they are therapies with high complexity that require a complex logistic approach for implementation; a very high cost and possible inducement of important side effects such as immunological issues (porcine endogenous retrovirus transmission), infectious complications and tumor transmigration have been documented. Other biological hepatic systems are Bioartificial Liver Support (BLSS)12 and Radial Flow Bioreactor (RFB).15 Detoxification capacity of these systems is poor and therefore they must be used combined with other systems to mitigate this deficiency. Today its use is limited to centers with high experience in their application. Artificial liver support systems are aimed to temporally replace native liver detoxification functions and they use albumin as scavenger molecule to clear the toxins involved in the physiopathology of the failing liver. Most of the toxins that accumulate in the plasma of patients with liver insufficiency are protein bound, and therefore conventional renal dialysis techniques, such as hemofiltration, hemodialysis or hemodiafiltration are not able to adequately eliminate them. Between the different albumin dialysis modalities, single pass albumin dialysis (SPAD) has shown some positive results at a very high cost; it has been proposed that lowering the concentration of albumin in the dialysate does not seem to affect the detoxification capability of the procedure. Nevertheless, the most widely used systems today are based on hemodialysis and adsorption. These systems use conventional dialysis methods with an albumin containing dialysate that is later regenerated by means of adsorption columns, filled with activated charcoal and ion exchange resins. At present, there are two artificial extracorporeal liver support systems: the Molecular Adsorbents Recirculating System (MARS)10 from Gambro and Fractionated Plasma Separation and Adsorption (FPSA), commercialised as Prometheus (PROM) from Fresenius Medical Care.13 Of the two therapies, MARS is the most frequently studied, and clinically used system to date.
  • 508
  • 29 Nov 2022
Biography
Robert Curbeam
Robert Lee Curbeam, Jr. (born March 5, 1962) is a former NASA astronaut and captain in the United States Navy.[1] Curbeam graduated from Woodlawn High School, Baltimore County, Maryland in 1980. He earned a Bachelor of Science degree in Aerospace Engineering from the United States Naval Academy in 1984, a Master of Science degree in Aeronautical Engineering from the Naval Postgraduate School in
  • 506
  • 30 Nov 2022
Biography
Earl Schuyler Kleinhans
Earl Schuyler (Sky) Kleinhans (February 3, 1905 – September 21, 1996) was an airplane and flying boat aeronautical engineering pioneer with primary experience at Sikorsky and Douglas Aircraft where he advanced over a 36-year career to become chief engineer and retired as the Chairman of the Scientific Advisory Board in 1969 for McDonnell Douglas. Some of the engineering talent of Sky Kleinh
  • 504
  • 15 Nov 2022
Topic Review
RMX (Operating System)
iRMX is a real-time operating system designed specifically for use with the Intel 8080 and 8086 family of processors. It is an acronym for Real-time Multitasking eXecutive.
  • 504
  • 06 Dec 2022
Biography
Leonard Greene
Leonard Michael Greene (June 8, 1918 – November 30, 2006) was an American inventor and aerodynamics engineer who held more than 200 patents, many of which are aviation-related. He is most well known for his contributions to aviation technology, including his invention, the Aircraft Stall Warning device, which warns pilots when a deadly aerodynamic stall is imminent. To build the device, Greene
  • 504
  • 29 Dec 2022
Biography
Alexander A. Nikolsky
Alexander Alexandrovitch Nikolsky (Russian: Александр Александрович Никольский, 1903-1963) was a Russia n-born American aeronautical engineer who worked in the domain of rotary-wing aircraft. Professor Alexander Alexandrovitch Nikolsky (nicknamed "Nick"), was born in 1903 in the Russian Empire. He began his career as a cadet in the Russian Imperial Navy. He was se
  • 503
  • 14 Dec 2022
Topic Review
Xiaomi Smart Home
Xiaomi Smart Home Products (also known as Mi Ecosystem products) are products released by third-party manufacturers who have partnered with Xiaomi. These products are managed by Mi Home app.
  • 502
  • 22 Nov 2022
Topic Review
Sugar as Snow Analog in Penetration Testing
Understanding the mechanical properties of snow and ice is necessary for the efficient design and construction of cold regions infrastructure. Testing and evaluation is most commonly undertaken in situ or using samples within cold labs. However, there is an inevitable uncertainty as to the accuracy of results obtained from ex situ testing. Therefore, development of suitable proxies for snow, such as sugar or foam, is valuable, potentially enabling further research in this field.
  • 501
  • 06 Apr 2022
  • Page
  • of
  • 50
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
ScholarVision Creations
Feedback