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Topic Review
French Cruiser Dupleix (1930)
Dupleix was the fourth unit of the Suffren class. She entered service in 1933 and spent the interwar period in the Mediterranean. She participated in the International Patrol during the Spanish Civil War. September 1939 found her still in Toulon. She participated in the search for the Graf Spee in the Atlantic before returning to Toulon. The only time she fired her guns in anger was during the bombardment of Vado, Italy in mid-June 1940. She was at Toulon at the time of the Franco-German Armistice in June 1940. She remained at Toulon until the French Fleet there was scuttled in late November 1942. She was subsequently raised by the Italians in 1943. She was named in honour of Joseph François, Marquis Dupleix (1697 - 1763) a French trader in the service of La Compagnie des Indes. He travelled between North America and India. He was appointed Governor-General of French India in 1742. A post he held until his death in 1763.
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Topic Review
Mount Polley Tailings Spill
The Mount Polley tailings spill occurred in the Cariboo region of central British Columbia, Canada . The spill began 4 August 2014 with a breach of the Imperial Metals-owned Mount Polley copper, gold and silver mine tailings pond, releasing its water and slurry with years worth of mining waste into Polley Lake. The spill flooded Polley Lake, creating a plug at Hazeltine Creek, and continued into nearby Quesnel Lake and Cariboo River. By 8 August the four-square-kilometre (1.5 sq mi) sized tailings pond had been emptied of the majority of supernatant (process water) that sits atop the settled crushed rock solids (mining waste, or 'tailings'). The cause of the dam breach and subsequent tailings spill has been investigated with a final report published 31 January 2015. Imperial Metals had a history of operating the pond beyond capacity since at least 2011. Remediation and reconstruction has been underway at the site since 2014. These efforts have included investigation on impacts to human health and safety and affected ecosystems while removing the tailings spill, reconstructing creek shorelines, installing fish habitats, and replanting trees and other local vegetation. Investigation by the remediation team showed elevated levels of selenium, arsenic and other metals consistent with historical tests before the dam breach. These initial reports had been concerned about the chemical impact of the tailings spill on the surrounding environment, but it was determined through subsequent investigation and remediation that the challenge posed by tailings spill was physical in nature.
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Topic Review
Sound Reduction Index
The sound reduction index is used to measure the level of sound insulation provided by a structure such as a wall, window, door, or ventilator. It is defined in the series of international standards ISO 16283 (parts 1-3) and the older ISO 140 (parts 1-14), or the regional or national variants on these standards. In the United States, the sound transmission class rating is generally used instead. The basic method for both the actual measurements and the mathematical calculations behind both standards is similar, however they diverge to a significant degree in the detail, and in the numerical results produced. Standardized methods exist for measuring the sound insulation produced by various structures in both laboratory and field (actual functional buildings and building sites) environments. A number of indexes are defined which each offer various benefits for different situations.
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Topic Review
Detroit Diesel 60
The Detroit Diesel Series 60 is an inline-six 4 stroke diesel engine produced since 1987. At that time, it differed from most on-highway engines by using an overhead camshaft and "drive by wire" electronic control. In 1993, it was popular on many USA buses in the 11.1 L (677 cu in) displacement.
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Topic Review
CMOS Amplifiers
CMOS amplifiers are ubiquitous analog circuits which are used in computers, audio systems, smart phones, cameras, telecommunication systems, biomedical circuits and many other systems, and their performance has great impact on the overall specifications of the systems. They take their name from the use of MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as opposite to Bipolar Junction Transistors (BJT). MOSFETS are simpler to fabricate and therefore less expensive than BJT amplifiers, still providing a sufficiently high transconductance to allow the design of very high performance circuits. In high performance CMOS amplifier circuits, transistors are not only used to amplify the signal but are also used as active loads to achieve higher gain and output swing in comparison with resistive loads. CMOS technology had been primarily introduced to design digital circuits. In the last decades, in order to improve speed, power consumption, required area and other aspects of digital integrated circuits (ICs), the feature size of MOSFET transistors has shrunk (minimum channel length of transistors reduces in newer CMOS technologies). This phenomenon predicted by Gordon Moore in 1975, which is called Moore’s law, and states that in about each 2 years, the number of transistors doubles for the same silicon area of ICs. Progress in memory circuits design is an interesting example to see how process advancement have affected the required size and their performance in the last decades. In 1956, a 5MB Hard Disk Drive (HDD) weighted over a tone, while these days having 50000 times more capacity with a weight of several tens of grams is very common. While digital ICs have enormously benefited from the feature size shrinking, analog CMOS amplifiers have not gained corresponding advantages due to the intrinsic limitations imposed by an analog design, like the intrinsic gain reduction of short channel transistors which affects the overall gain of amplifier. Novel techniques to achieve higher gain also create new problems, like stability of amplifier for closed-loop applications. In the following, we will address both aspects and summarize few different methods to overcome these problems.
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Topic Review
History of the Aircraft Carrier
Aircraft carriers are warships that evolved from balloon-carrying wooden vessels into nuclear-powered vessels carrying scores of fixed- and rotary-wing aircraft. Since their introduction they have allowed naval forces to project air power great distances without having to depend on local bases for staging aircraft operations. Balloon carriers were the first ships to deploy manned aircraft, used during the 19th and early 20th century, mainly for observation purposes. The advent of fixed-wing aircraft in 1903 was followed in 1910 by the first flight from the deck of a US Navy cruiser. Seaplanes and seaplane tender support ships, such as HMS Engadine, followed. The development of flat top vessels produced the first large fleet ships. This evolution was well underway by the early to mid-1920s, resulting in the commissioning of ships such as Hōshō (1922), HMS Hermes (1924), Béarn (1927), and the Lexington-class aircraft carriers (1927). Most early aircraft carriers were conversions of ships that were laid down (or had even served) as different ship types: cargo ships, cruisers, battlecruisers, or battleships. During the 1920s, several navies started ordering and building aircraft carriers that were specifically designed as such. This allowed the design to be specialized to their future role, and resulted in superior ships. During the Second World War, these ships would become the backbone of the carrier forces of the US, British, and Japanese navies, known as fleet carriers. World War II saw the first large-scale use of aircraft carriers and induced further refinement of their launch and recovery cycle leading to several design variants. The USA built small escort carriers, such as USS Bogue, as a stop-gap measure to provide air support for convoys and amphibious invasions. Subsequent light aircraft carriers, such as USS Independence, represented a larger, more "militarized" version of the escort carrier concept. Although the light carriers usually carried the same size air groups as escort carriers, they had the advantage of higher speed as they had been converted from cruisers under construction.
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Topic Review
Dialysis
In medicine, dialysis (from Greek διάλυσις, dialysis, "dissolution"; from διά, dia, "through", and λύσις, lysis, "loosening or splitting") is the process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer perform these functions naturally. This is referred to as renal replacement therapy. The first successful dialysis was performed in 1943. Dialysis may need to be initiated when there is a sudden rapid loss of kidney function, known as acute kidney injury (previously called acute renal failure), or when a gradual decline in kidney function, chronic kidney disease, reaches stage 5. Stage 5 chronic renal failure is reached when the glomerular filtration rate is 10–15% of normal, creatinine clearance is less than 10 mL per minute and uremia is present. Dialysis is used as a temporary measure in either acute kidney injury or in those awaiting kidney transplant and as a permanent measure in those for whom a transplant is not indicated or not possible. In Australia, Canada, the United Kingdom, and the United States, dialysis is paid for by the government for those who are eligible. In research laboratories, dialysis technique can also be used to separate molecules based on their size. Additionally, it can be used to balance buffer between a sample and the solution "dialysis bath" or "dialysate" that the sample is in. For dialysis in a laboratory, a tubular semipermeable membrane made of cellulose acetate or nitrocellulose is used. Pore size is varied according to the size separation required with larger pore sizes allowing larger molecules to pass through the membrane. Solvents, ions and buffer can diffuse easily across the semipermeable membrane, but larger molecules are unable to pass through the pores. This can be used to purify proteins of interest from a complex mixture by removing smaller proteins and molecules.
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Topic Review
Operational View
Operational View (OV) is one of the basic views defined in the enterprise architecture (EA) of the Department of Defense Architecture Framework V1.5 (DoDAF) and is related with concept of operations. Under DODAF 2, which became operational in 2009, the collections of views are now termed 'viewpoints' and no longer views. Other enterprise architecture frameworks may or do have operational views. For example, the MODAF has an Operational Viewpoint and the NATO Architecture Framework has an Operational View (collection of subviews). This article will further explain the construction of the Operational View of the DoDAF V1.5.
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Topic Review
Hybrid Fibre-Coaxial
Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s. In a hybrid fiber-coaxial cable system, the television channels are sent from the cable system's distribution facility, the headend, to local communities through optical fiber subscriber lines. At the local community, a box called an optical node translates the signal from a light beam to radio frequency (RF), and sends it over coaxial cable lines for distribution to subscriber residences. The fiberoptic trunk lines provide adequate bandwidth[weasel words] to allow future expansion and new bandwidth-intensive services.
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Topic Review
List of Seaplanes and Amphibious Aircraft
The following is a list of seaplanes and amphibious aircraft, which includes floatplanes and flying boats, by country of origin. Seaplanes are any aircraft that has the capability of landing on water while amphibious aircraft are equipped with wheels to alight on land, as well as being able to land on the water. Flying boats rely on the fuselage or hull for buoyancy, while floatplanes rely on external pontoons or floats. Some experimental aircraft used specially designed skis to skim across the water but did not always have a corresponding ability to float. This list does not include ekranoplans, 'Wing-In-Ground-effect' (WIG), water-skimmers, wingships or similar vehicles reliant on ground effect.
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