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Topic Review
Catalyst Design via Colloidal Synthesis
Supported nanoparticles are commonly applied in heterogeneous catalysis. The catalytic performance of these solid catalysts is, for a given support, dependent on the nanoparticle size, shape, and composition, thus necessitating synthesis techniques that allow for preparing these materials with fine control over those properties. Such control can be exploited to deconvolute their effects on the catalyst’s performance, which is the basis for knowledge-driven catalyst design. In this regard, bottom-up synthesis procedures based on colloidal chemistry have proven successful in achieving the desired level of control for a variety of fundamental studies. This article aims to give an overview of recent progress made in this synthesis technique for the application of controlled catalytic materials in gas-phase catalysis. The focus goes to mono- and bimetallic materials, as well as to recent efforts in enhancing their performance by embedding colloidal templates in porous oxide phases.
  • 4.0K
  • 12 May 2021
Topic Review
Spray freeze-drying in pharmaceutical products
Pharmaceutical manufacturing is evolving from traditional batch processes to continuous ones. The present review deals with the most recent technologies, based on spray freeze-drying, that can achieve this objective. It provides a comprehensive overview of the physics behind this process and of the most recent equipment design.
  • 4.0K
  • 27 Oct 2020
Topic Review
Royal Ordnance L7
The Royal Ordnance L7 is the basic model of the United Kingdom 's most successful tank gun. The L7 is a 105 mm L/52 rifled design by the Royal Ordnance Factories intended for use in armoured fighting vehicles, replacing the earlier 20-pounder (84 mm) tank gun mounted on the Centurion tank. The successful L7 gun has been fitted on many armored vehicles including the British Centurion (starting from the Mk. 5/2 variant), the German Leopard 1 and early variants of the US M1 Abrams (M1 and M1IP). The L7 is a popular weapon and continued in use even after it was superseded by the L11 series 120 mm rifled tank gun, for some Centurion tanks operating as Artillery Forward Observation and Armoured Vehicle, Royal Engineers (AVRE) vehicles. The L7, and adaptations of it, can be found as standard or retrofitted equipment on a wide variety of tanks developed during the Cold War.
  • 3.9K
  • 08 Nov 2022
Biography
William Boeing
William Edward Boeing (/ˈboʊɪŋ/; October 1, 1881 – September 28, 1956) was an United States aviation pioneer who founded The Boeing Company in 1916. Boeing was born in Detroit, Michigan to Marie M. Ortmann, from Vienna, Austria, and Wilhelm Böing (1846–1890) from Hagen-Hohenlimburg, Germany.[1] From a successful family, Wilhelm Böing emigrated to the United States in 1868 and initia
  • 3.9K
  • 05 Dec 2022
Topic Review
History of Statistics
The history of statistics in the modern way is that it originates from the term statistics, found in 1749 in Germany. Although there have been changes to the interpretation of the word over time. The development of statistics is intimately connected on the one hand with the development of sovereign states, particularly European states following the peace of Westphalia (1648); and the other hand with the development of probability theory, which put statistics on a firm theoretical basis (see history of probability). In early times, the meaning was restricted to information about states, particularly demographics such as population. This was later extended to include all collections of information of all types, and later still it was extended to include the analysis and interpretation of such data. In modern terms, "statistics" means both sets of collected information, as in national accounts and temperature records, and analytical work which requires statistical inference. Statistical activities are often associated with models expressed using probabilities, hence the connection with probability theory. The large requirements of data processing have made statistics a key application of computing; see history of computing hardware. A number of statistical concepts have an important impact on a wide range of sciences. These include the design of experiments and approaches to statistical inference such as Bayesian inference, each of which can be considered to have their own sequence in the development of the ideas underlying modern statistics.
  • 3.9K
  • 19 Oct 2022
Topic Review
Passivation
Passivation, in physical chemistry and engineering, refers to coating a material so it becomes "passive", that is, less readily affected or corroded by the environment. Passivation involves creation of an outer layer of shield material that is applied as a microcoating, created by chemical reaction with the base material, or allowed to build by spontaneous oxidation in the air. As a technique, passivation is the use of a light coat of a protective material, such as metal oxide, to create a shield against corrosion. Passivation of silicon is used during fabrication of microelectronic devices. In electrochemical treatment of water, passivation reduces the effectiveness of the treatment by increasing the circuit resistance, and active measures are typically used to overcome this effect, the most common being polarity reversal, which results in limited rejection of the fouling layer.[clarification needed] When exposed to air, many metals naturally form a hard, relatively inert surface layer, usually an oxide (termed the "native oxide layer") or a nitride, that serves as a passivation layer. In the case of silver, the dark tarnish is a passivation layer of silver sulfide formed from reaction with environmental hydrogen sulfide. (In contrast, metals such as iron oxidize readily to form a rough porous coating of rust that adheres loosely and sloughs off readily, allowing further oxidation.) The passivation layer of oxide markedly slows further oxidation and corrosion in room-temperature air for aluminium, beryllium, chromium, zinc, titanium, and silicon (a metalloid). The inert surface layer formed by reaction with air has a thickness of about 1.5 nm for silicon, 1–10 nm for beryllium, and 1 nm initially for titanium, growing to 25 nm after several years. Similarly, for aluminium, it grows to about 5 nm after several years. Surface passivation refers to a common semiconductor device fabrication process critical to modern electronics. It is the process by which a semiconductor surface such as silicon is rendered inert, and does not change semiconductor properties when it interacts with air or other materials. This is typically achieved by thermal oxidation, in which the material is heated and exposed to oxygen. In a silicon semiconductor, this process allows electricity to reliably penetrate to the conducting silicon below the surface, and to overcome the surface states that prevent electricity from reaching the semiconducting layer. Surface passivation by thermal oxidation is one of the key features of silicon technology, and is dominant in microelectronics. The surface passivation process was developed by Mohamed M. Atalla at Bell Labs in the late 1950s. It is commonly used to manufacture MOSFETs (metal-oxide-semiconductor field-effect transistors) and silicon integrated circuit chips (with the planar process), and is critical to the semiconductor industry. Surface passivation is also critical to solar cell and carbon quantum dot technologies.
  • 3.9K
  • 03 Nov 2022
Topic Review
76 Mm Gun M1
The 76 mm gun M1 was an American World War II–era tank gun developed by the U.S Ordnance Department in 1942 to supplement the 75 mm gun on the basic Medium tank M4. It was also used to arm the 76 mm Gun Motor Carriage M18 tank destroyer. Although the gun was tested in early August 1942 and classified on August 17, 1942, it was not until August 1943 that the Ordnance Department developed a mounting for the M4 tank that the tank forces would accept. It was not accepted for combat until July 1944. In January 1943, the decision was made to mount the 76 mm on the vehicle that would become the M18. By May 1944, it was being combat tested as the T70.
  • 3.9K
  • 11 Nov 2022
Topic Review
Energy Technology
Energy technology is an interdisciplinary engineering science having to do with the efficient, safe, environmentally friendly, and economical extraction, conversion, transportation, storage, and use of energy, targeted towards yielding high efficiency whilst skirting side effects on humans, nature, and the environment. For people, energy is an overwhelming need, and as a scarce resource, it has been an underlying cause of political conflicts and wars. The gathering and use of energy resources can be harmful to local ecosystems and may have global outcomes. Energy is also the capacity to do work. We can get energy from food. Energy can be of different forms such as kinetic, potential, mechanical, heat, light etc. Energy is required for individuals and the whole society for lighting, heating, cooking, running, industries, operating transportation and so forth. Basically there are two types of energy depending on the source s they are; 1.Renewable Energy Sources 2.Non-Renewable Energy Sources
  • 3.9K
  • 11 Nov 2022
Topic Review
Livery
A livery /ˈlɪvəri/ is a uniform, insignia or symbol adorning, in a non-military context, a person, an object or a vehicle that denotes a relationship between the wearer of the livery and an individual or corporate body. Often, elements of the heraldry relating to the individual or corporate body feature in the livery. Alternatively, some kind of a personal emblem or badge, or a distinctive colour, is featured. The word itself derives from the French livrée, meaning dispensed, handed over. Most often it would indicate that the wearer of the livery was a servant, dependant, follower or friend of the owner of the livery, or, in the case of objects, that the object belonged to them. In the late medieval phenomenon of bastard feudalism, livery badges worn by the "retainers" of great lords, sometimes in effect private armies, became a great political concern in England.
  • 3.8K
  • 01 Dec 2022
Topic Review
List of Intel Pentium Microprocessors
The Intel Pentium brand refers to mainstream x86-architecture microprocessors from Intel. Processors branded Pentium Processor with MMX Technology (and referred to as Pentium MMX for brevity) are also listed here.
  • 3.8K
  • 26 Oct 2022
Topic Review
Adjustable-Speed Drive
Adjustable speed drive (ASD), also known as variable-speed drive (VSD), describes equipment used to control the speed of machinery. Many industrial processes such as assembly lines must operate at different speeds for different products. Where process conditions demand adjustment of flow from a pump or fan, varying the speed of the drive may save energy compared with other techniques for flow control. Where speeds may be selected from several different pre-set ranges, usually the drive is said to be adjustable speed. If the output speed can be changed without steps over a range, the drive is usually referred to as variable speed. Adjustable and variable speed drives may be purely mechanical (termed variators), electromechanical, hydraulic, or electronic.
  • 3.7K
  • 10 Nov 2022
Topic Review
Zip (File Format)
ZIP files generally use the file extensions .zip or .ZIP and the MIME media type application/zip. ZIP is used as a base file format by many programs, usually under a different name. When navigating a file system via a user interface, graphical icons representing ZIP files often appear as a document or other object prominently featuring a zipper.
  • 3.7K
  • 14 Oct 2022
Topic Review
Sami Drum
A Sami drum is a shamanic ceremonial drum in the culture of the Sami people of Northern Europe. Sami ceremonial drums have two types: a bowl drum in which the drumhead is strapped over a burl, and a frame drum in which the drumhead stretches over a thin ring of bentwood. Both variations are oval-shaped. The drumhead is fashioned from reindeer hide. In Sami shamanism, the noaidi – the Sami shaman – used the drum to get into a trance, or to obtain information from the future or about other places. The drum was held in one hand, and operated with the other hand. While the noaidi was in trance, his free spirit left his body to visit the spiritual world or other places. When used for divination purposes, the drum was used together with a drum hammer and an vuorbi (index or pointer) made of brass or horn. Answers could be interpreted from where the vuorbi stopped on the membrane, and at which symbols. The patterns on the drum membrane reflect the world view of the owner and his family, both in religious and worldly matters, such as reindeer herding, hunting, householding and relations to their neighbours and to the non-Sami community. Many drums were taken out of their use and Sami ownership during the 18th century. A large number of drums were confiscated by Sami missionaries and other officials as a part of an intensified Christian mission towards the Sami. Other drums were bought by collectors. Between 70 and 80 drums are preserved; the largest collection of drums is at the Nordic Museum, Stockholm.
  • 3.7K
  • 27 Oct 2022
Topic Review
Biomimicry
Biomimicry can be defined as the branch of science for developing technology by mimicking nature, where forms and structures of creatures are the basic sources of inspiration to come up with optimized design solutions.
  • 3.6K
  • 12 Mar 2021
Topic Review
AI-Based and Big Data Analytics on Urban Planning
In order to enable a holistic approach to design and planning, there is a need to integrate those data sources and combine them with other more traditional methods of urban assessment. At the same time, there are still various concerns about big data analytics based on AI-related tools connected, for example, with the accessibility to and accuracy of big data, as well as the limitations of different types of AI-based tools which do not permit this kind of analytics to fully replace traditional urban planning analyses. In terms of technological change, the application of big data in design and planning may greatly support traditional planning methods and provide conditions for innovation; however, due to its limitations, it can only enrich but in no way replace traditional urban studies.
  • 3.6K
  • 03 Dec 2021
Topic Review
Fuel Dispenser
A fuel dispenser is a machine at a filling station that is used to pump gasoline, petrol, diesel, CNG, CGH2, HCNG, LPG, LH2, ethanol fuel, biofuels like biodiesel, kerosene, or other types of fuel into vehicles. Fuel dispensers are also known as bowsers (in Australia ), petrol pumps (in Commonwealth countries), or gas pumps (in North America).
  • 3.6K
  • 06 Dec 2022
Topic Review
An Informative Lithium-Ion Battery Datasheet
Lithium-ion battery datasheets, also known as specification sheets, are documents that battery manufacturers provide to define the battery’s function, operational limit, performance, reliability, safety, cautions, prohibitions, and warranty. A datasheet lists information about the product for both informational and advertising purposes. Product manufacturers and customers rely on the datasheets for battery selection and battery management. 
  • 3.6K
  • 29 Sep 2021
Topic Review
Thorium-Based Nuclear Power
Thorium-based nuclear power generation is fueled primarily by the nuclear fission of the isotope uranium-233 produced from the fertile element thorium. A thorium fuel cycle can offer several potential advantages over a uranium fuel cycle [Note 1] —including much greater abundance of thorium found on Earth, superior physical and nuclear fuel properties, and reduced nuclear waste production. One advantage of thorium fuel is its low weaponization potential; it is difficult to weaponize the uranium-233/232 and plutonium-238 isotopes largely consumed in thorium reactors. Between 1999 and , the number of operational thorium reactors in the world has risen from zero, to a handful of research reactors, to commercial plans for producing full-scale thorium-based reactors for use as power plants on a national scale. Some believe thorium is key to developing a new generation of cleaner, safer nuclear power. In 2011 a group of scientists at the Georgia Institute of Technology assessed thorium-based power as "a 1000+ year solution or a quality low-carbon bridge to truly sustainable energy sources solving a huge portion of mankind’s negative environmental impact." However, development of thorium power has significant start-up costs. Development of breeder reactors in general (including thorium reactors, which are breeders by nature) will increase proliferation concerns. After studying the feasibility of using thorium, nuclear scientists Ralph W. Moir and Edward Teller suggested that thorium nuclear research should be restarted after a three-decade shutdown and that a small prototype plant should be built.
  • 3.6K
  • 18 Oct 2022
Topic Review
Railway Nationalization
Railway nationalization is the act of taking rail transport assets into public ownership. Several countries have at different times nationalized part or all of their railway system. More recently, the international trend has been towards privatization. In some areas, notably Great Britain, resultant problems with track maintenance have led back to a more mixed solution, with a nationalised infrastructure operator but privately run train operating companies. National characteristics influenced the structures under which countries' rail networks developed. Some national railways were always under direct State management, some were State-planned but privately operated (as in France, others were wholly private enterprises lightly regulated (as in Great Britain, Ireland and Spain). Nationalization was therefore a bolder step to take in some countries than in others. While ideology has played a role, so too has the need for systematic reconstruction of vital infrastructure devastated by war, often following a period of State control over private companies initiated during the conflict.
  • 3.5K
  • 01 Dec 2022
Topic Review
9K111 Fagot
The 9K111 Fagot (Russian: Фагот; "bassoon") is a second-generation tube-launched SACLOS wire-guided anti-tank missile system of the Soviet Union for use from ground or vehicle mounts. The 9K111 Fagot missile system was developed by the Tula KBP Design Bureau for Instrument Building. "9M111" is the GRAU designation of the missile. Its NATO reporting name is AT-4 Spigot.
  • 3.5K
  • 21 Oct 2022
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