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Topic Review
Process of Converting Ammonia to Hydrogen
Hydrogen technology for transition to a hydrogen-based economy requires supplying clean and renewable energy and capture of CO2 from current fossil hydrogen production. Ammonia is the most popular substance as a green hydrogen carrier because it does not carry carbon, and the total hydrogen content of ammonia is higher than other fuels and is thus suitable to convert to hydrogen. Ammonia cracking is a process of producing hydrogen from ammonia decomposition over a catalyst at high temperatures and is preferentially performed at normal pressures. 
  • 21.0K
  • 12 Dec 2022
Topic Review
List of Assyrian Tribes
This page features a list of Assyrian clans or tribes historically centered in the Hakkari, Sirnak and Mardin provinces in Turkey and West Azerbaijan Province in Iran, prior to 1915, or before Seyfo, when they were historically Assyrian settlements, before early 20th century resettlement in Northern Iraq (which simultaneously had Catholic-Assyrian tribes since the 1st millennium) and northwestern Syria (namely in Al-Hasakah) after they were displaced, slaughtered and driven out by Ottoman Turks in 1915 and in the early 1930s, respectively, during the Simele massacre where they endured a similar anguish and predicament. From around 2500 BC, Assyrians primarily lived in the ancient Assyrian cities of Nineveh, Assur, Nohadra, Arrapha and Arbela, which now lie in modern-day northern Iraq, and as well as the mountainous Assyrian region of Hakkari in what is now Turkey, from around 2300 BC. Though after the spread of Islam, many eventually left the ancient Assyrian cities in the Nineveh Plains, where they settled and found refuge in the highland region in southeastern Anatolia, with the existing Assyrian population, and northwestern Iran. The villages in southeastern Turkey are primarily centred in the modern-day towns of Yuksekova, Çukurca and Semdinli in Hakkâri, Uludere in Sirnak Province and Tur Abdin in Mardin Province. Most of the historical Assyrian tribes are located in the region stretching from Tur Abdin to Hakkari, in Upper Mesopotamia, which formed the Nairi lands, serving as the northern Assyrian frontier and border with their Urartian rivals. The Assyrians of this region were Nestorian Christians adhering to the Assyrian Church of the East and lived here until 1924, when the very last Assyrians who survived the Assyrian Genocide and massacres that occurred during 1918 were expelled. Most subsequently moved to the Nahla valley in northern Iraq or elsewhere. The people of these tribes are an ancient people of Mesopotamia who speak Assyrian Neo-Aramaic, a modern Syriac language that's derived from old Aramaic and has influences of Akkadian. In the early-mid 20th century, most settled in Iraq, Jordan, Syria and Iran, where many eventually immigrated to the western world in recent years.
  • 20.9K
  • 02 Dec 2022
Topic Review
Cretaceous–Paleogene Extinction Event
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the Cretaceous–Tertiary (K–T) extinction,[lower-alpha 2] was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the exception of some ectothermic species such as the sea turtles and crocodilians, no tetrapods weighing more than 25 kilograms (55 pounds) survived. It marked the end of the Cretaceous period, and with it the end of the entire Mesozoic Era, opening the Cenozoic Era that continues today. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows high levels of the metal iridium, which is rare in the Earth's crust, but abundant in asteroids. As originally proposed in 1980 by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused by the impact of a massive comet or asteroid 10 to 15 km (6 to 9 mi) wide, 66 million years ago, which devastated the global environment, mainly through a lingering impact winter which halted photosynthesis in plants and plankton. The impact hypothesis, also known as the Alvarez hypothesis, was bolstered by the discovery of the 180 km (112 mi) Chicxulub crater in the Gulf of Mexico's Yucatán Peninsula in the early 1990s, which provided conclusive evidence that the K–Pg boundary clay represented debris from an asteroid impact. The fact that the extinctions occurred simultaneously provides strong evidence that they were caused by the asteroid. A 2016 drilling project into the Chicxulub peak ring confirmed that the peak ring comprised granite ejected within minutes from deep in the earth, but contained hardly any gypsum, the usual sulfate-containing sea floor rock in the region: The gypsum would have vaporized and dispersed as an aerosol into the atmosphere, causing longer-term effects on the climate and food chain. In October 2019, researchers reported that the event rapidly acidified the oceans producing ecological collapse and, in this way as well, produced long-lasting effects on the climate, and accordingly was a key reason for the end-Cretaceous mass extinction. In January 2020, scientists reported new evidence that the extinction event was mostly a result of the meteorite impact and not volcanism. Other causal or contributing factors to the extinction may have been the Deccan Traps and other volcanic eruptions, climate change, and sea level change. A wide range of species perished in the K–Pg extinction, the best-known being the non-avian dinosaurs. It also destroyed a myriad of other terrestrial organisms, including some mammals, pterosaurs, birds, lizards, insects, and plants. In the oceans, the K–Pg extinction killed off plesiosaurs and mosasaurs and devastated teleost fish, sharks, mollusks (especially ammonites, which became extinct), and many species of plankton. It is estimated that 75% or more of all species on Earth vanished. Yet the extinction also provided evolutionary opportunities: In its wake, many groups underwent remarkable adaptive radiation — sudden and prolific divergence into new forms and species within the disrupted and emptied ecological niches. Mammals in particular diversified in the Paleogene, evolving new forms such as horses, whales, bats, and primates. The surviving group of dinosaurs were avians, ground and water fowl who radiated into all modern species of bird. Teleost fish, and perhaps lizards also radiated.
  • 20.9K
  • 03 Nov 2022
Topic Review
Erikson's Stages of Psychosocial Development
Erikson's stages of psychosocial development, as articulated in the second half of the 20th century by Erik Erikson in collaboration with Joan Erikson, is a comprehensive psychoanalytic theory that identifies a series of eight stages that a healthy developing individual should pass through from infancy to late adulthood. According to Erikson’s theory the results from each stage, whether positive or negative, influences the results of succeeding stages. Erikson published a book called Childhood and Society around the 1950s that made his research well known on the eight stages of psychosocial development. Erikson was originally influenced by Sigmund Freud’s psychosexual stages of development. He began by working with Freud's theories specifically, but as he began to dive deeper into biopsychosocial development and how other environmental factors affect human development, he soon progressed past Freud’s theories and developed his own ideas. Erikson's stage theory characterizes an individual advancing through the eight life stages as a function of negotiating their biological and sociocultural forces. The two conflicting forces each have a psychosocial crisis which characterizes the eight stages. If an individual does indeed successfully reconcile these forces (favoring the first mentioned attribute in the crisis), they emerge from the stage with the corresponding virtue. For example, if an infant enters into the toddler stage (autonomy vs. shame and doubt) with more trust than mistrust, they carry the virtue of hope into the remaining life stages. The challenges of stages not successfully completed may be expected to return as problems in the future. However, mastery of a stage is not required to advance to the next stage. In one study, subjects showed significant development as a result of organized activities.
  • 20.8K
  • 20 Oct 2022
Topic Review
Physical Law
A physical law or a law of physics is a statement "inferred from particular facts, applicable to a defined group or class of phenomena, and expressible by the statement that a particular phenomenon always occurs if certain conditions be present." Physical laws are typically conclusions based on repeated scientific experiments and observations over many years and which have become accepted universally within the scientific community. The production of a summary description of our environment in the form of such laws is a fundamental aim of science. These terms are not used the same way by all authors. The distinction between natural law in the political-legal sense and law of nature or physical law in the scientific sense is a modern one, both concepts being equally derived from physis, the Greek word (translated into Latin as natura) for nature.
  • 20.8K
  • 01 Dec 2022
Topic Review
Nutritional Value of Fish
Fish are considered highly nutritious products of the aquaculture system due to the presence of well-balanced macronutrients such as proteins, lipids and micronutrients such as vitamins and minerals
  • 20.7K
  • 28 Nov 2022
Topic Review
Onion Dome
An onion dome (Russian: луковичная глава, lúkovichnaya glavá; compare Russian: лук, luk, "onion") is a dome whose shape resembles an onion and is usually associated with Russia n architectural style. Such domes are often larger in diameter than the tholobate upon which they sit, and their height usually exceeds their width. These bulbous structures taper smoothly to a point. It is a typical feature of churches belonging to Russian Orthodox church. Occasionally, there are similar buildings in European countries like in Germany in Bavaria, (German: Zwiebelturm (literally "onion tower") in Austria, the Czech Republic, northeastern Italy, in other Eastern European countries and in Oriental regions like Mughal India, the Middle East and Central Asia. However, the old buildings outside of Russia usually do not have the distinctive typical construction of the Russian onion design. Probably the origin lies in the native architectural style of early Rus' tribes. Other types of Eastern Orthodox cupolas include helmet domes (for example, those of the Assumption Cathedral in Vladimir), Ukrainian pear domes (Saint Sophia Cathedral in Kiev), and Baroque bud domes (St. Andrew's Church in Kiev) or an onion-helmet mixture like the Saint Sophia Cathedral in Novgorod.
  • 20.7K
  • 31 Oct 2022
Topic Review
Government Censorship of Telegram Messenger
Telegram Messenger application has been blocked by multiple countries.
  • 20.7K
  • 14 Nov 2022
Topic Review
2004 Indian Ocean Tsunami in Malaysia
The tsunami is one of the deadliest natural disasters, responsible for more than 260,000 deaths and billions in economic losses over the last two decades. The footage of the devastating power of the 2004 Indian Ocean tsunami perhaps remains vivid in the memory of most survivors, and Malaysia was one of the countries affected by the unprecedented 2004 tsunami. It was the first time the Malaysian government had managed such a great disaster. A compilation of post-event observations regarding tsunami characteristics is first presented in the form of maps, followed by building damage, including damage modes of wall failure, total collapse, debris impact and tilting of structures.
  • 20.6K
  • 17 Jun 2025
Topic Review
Unified Atomic Mass Unit
The unified atomic mass unit or dalton (symbol: u, or Da) is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic mass). One unified atomic mass unit is approximately the mass of one nucleon (either a single proton or neutron) and is numerically equivalent to 1 g/mol. It is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest, and has a value of 1.660539040(20)×10−27 kg, or approximately 1.66 yoctograms. The CIPM has categorised it as a non-SI unit accepted for use with the SI, and whose value in SI units must be obtained experimentally. The amu without the "unified" prefix is technically an obsolete unit based on oxygen, which was replaced in 1961. However, many sources still use the term amu but now define it in the same way as u (i.e., based on carbon-12). In this sense, most uses of the terms atomic mass units and amu, today, actually refer to unified atomic mass unit. For standardization, a specific atomic nucleus (carbon-12 vs. oxygen-16) had to be chosen because the average mass of a nucleon depends on the count of the nucleons in the atomic nucleus due to mass defect. This is also why the mass of a proton or neutron by itself is more than (and not equal to) 1 u. The atomic mass unit is not the unit of mass in the atomic units system, which is rather the electron rest mass (me).
  • 20.6K
  • 21 Oct 2022
Topic Review
Vaginal Discharge
Vaginal discharge is a mixture of liquid, cells, and bacteria that lubricate and protect the vagina. This mixture is constantly produced by the cells of the vagina and cervix, and it exits the body through the vaginal opening. The composition, amount, and quality of discharge varies between individuals and can vary throughout the menstrual cycle and throughout the stages of sexual and reproductive development. Normal vaginal discharge may have a thin, watery consistency or a thick, sticky consistency, and it may be clear or white in color. Normal vaginal discharge may be large in volume but typically does not have a strong odor, nor is it typically associated with itching or pain. While most discharge is considered physiologic or represents normal functioning of the body, some changes in discharge can reflect infection or other pathological processes. Infections that may cause changes in vaginal discharge include vaginal yeast infections, bacterial vaginosis, and sexually transmitted infections. The characteristics of abnormal vaginal discharge vary depending on the cause, but common features include a change in color, a foul odor, and associated symptoms such as itching, burning, pelvic pain, or pain during sexual intercourse.
  • 20.5K
  • 14 Nov 2022
Topic Review
Folk Dance
A folk dance is a dance developed by people that reflect the life of the people of a certain country or region. Not all ethnic dances are folk dances. For example, ritual dances or dances of ritual origin are not considered to be folk dances. Ritual dances are usually called "Religious dances" because of their purpose. The terms "ethnic" and "traditional" are used when it is required to emphasize the cultural roots of the dance. In this sense, nearly all folk dances are ethnic ones. If some dances, such as polka, cross ethnic boundaries and even cross the boundary between "folk" and "ballroom dance", ethnic differences are often considerable enough to mention.
  • 20.5K
  • 12 Oct 2022
Topic Review
Methods and Techniques for CO2 Capture
With the increase in electricity consumption around the world, electricity demands are increasing every day. During electricity generation using energy technologies based on fossil fuels, the emission of harmful pollutants into the environment (gaseous, liquid, and solid) occurs as the emission of NOx, SOx, dust, CO2, and wastewater (e.g., from flue-gas treatment installations). A great deal of effort in modern low-emission energy technologies was directed at activities leading to decreased gaseous pollutant emissions. The emission of carbon dioxide (CO2), treated as one of the main reasons for global warming when fossil fuel is burned, cannot be avoided. The carbon capture utilization and storage (CCUS) methods and technologies are among the many ways to reduce CO2 emissions.
  • 20.4K
  • 24 Oct 2024
Topic Review
Holocene Climatic Optimum
The Holocene Climate Optimum (HCO) was a warm period during roughly the interval 9,000 to 5,000 years BP, with a thermal maximum around 8000 years BP. It has also been known by many other names, such as Altithermal, Climatic Optimum, Holocene Megathermal, Holocene Optimum, Holocene Thermal Maximum, Hypsithermal, and Mid-Holocene Warm Period. This warm period was followed by a gradual decline until about two millennia ago.
  • 20.4K
  • 01 Nov 2022
Topic Review
Investment in Tourism Infrastructure Development
Investment in tourism infrastructure includes investment in components such as transport and communications infrastructure, the hotel and restaurant industry, and recreation facilities... Investment in tourism infrastructure development to make destinations and services increasingly attractive is considered a key measure in developing a country’s tourist destinations. It has a strong and positive impact on visitor attraction. 
  • 20.3K
  • 18 Sep 2021
Topic Review
Sensible and Latent Heat Thermal Energy Storage
Sharing renewable energies, reducing energy consumption and optimizing energy management in an attempt to limit environmental problems (air pollution, global warming, acid rain, etc.) has today become a genuine concern of scientific engineering research. Furthermore, with the drastic growth of requirements in building and industrial worldwide sectors, the need for proper techniques that allow enhancement in the thermal performance of systems is increasingly being addressed. It is worth noting that using sensible and latent heat storage materials (SHSMs and phase change materials (PCMs)) for thermal energy storage mechanisms can meet requirements such as thermal comfort in buildings when selected correctly.
  • 20.3K
  • 29 Jul 2022
Topic Review
Alpha (Ethology)
In studies of social animals, the highest ranking individual of a dominance hierarchy is sometimes designated as the alpha. Males, females, or both, can be alphas, depending on the species. Where one male and one female fulfill this role together, they are sometimes referred to as the alpha pair. Other animals in the same social group may exhibit deference or other species-specific subordinate behavior towards the alpha or alphas. Alpha animals usually gain preferential access to food and other desirable items or activities, though the extent of this varies widely between species. Male or female alphas may gain preferential access to sex or mates; in some species, only alphas or an alpha pair reproduce. Alphas may achieve their status by superior physical strength and aggression, or through social efforts and building alliances within the group, or more often, simply by breeding and being the parent of all in their pack. The individual with alpha status sometimes changes, often through a fight between the dominant and a subordinate animal. These fights are often to the death, depending on the animal.
  • 20.3K
  • 04 Nov 2022
Topic Review
Cement Production in Nigeria
Cement is the most common and extensively used adhesive in the construction industry. It is employed on highways, houses, embankments, bridges, commercial establishments, and flyovers. In recent years, the Nigerian cement industry has grown from import dependency to an export-thriving epicentre within Africa. The country possesses the largest cement industry within West Africa, with at least 12 registered companies amounting to a merged cement capacity of 58.9 Mt/yr. Dangote Cement is the largest cement producer in Nigeria and West Africa, manufacturing a combined share of more than 28.5 Mt/yr of cement capacity. Also, LafargeHolcim (through its subsidiary AshakaCem & Lafarge WAPCO) and BUA Group boost 18.9 Mt/yr and 11.5 Mt/yr of integrated cement capacity, respectively.
  • 20.3K
  • 16 Sep 2021
Topic Review
Digitalisation of organisations and COVID-19
The COVID-19 pandemic caused profound shifts in the functioning of organisations, with the increased mobilisation of the implementation of digitalisation processes in the activities of the members of these coordinated collective units. In this perspective, based on our academic experience and recent literature, this paper offers some dimensions that seem to us relevant to ponder with special urgency, and that will shape both organisations in the near future and an organisational culture that is, in many cases, renewed.
  • 20.2K
  • 28 Oct 2020
Topic Review
List of Socialist States
Several past and present states have declared themselves socialist states or in the process of building socialism. The majority of self-declared socialist countries have been Marxist–Leninist or inspired by it, following the model of the Soviet Union or some form of people's or national democracy. They share a common definition of socialism and they refer to themselves as socialist states on the road to communism with a leading vanguard party structure, hence they are often called communist states. Meanwhile, the countries in the non-Marxist–Leninist category represent a wide variety of different interpretations of the term socialism and in many cases the countries do not define what they mean by it. Modern uses of the term socialism are wide in meaning and interpretation. Because a sovereign state is a different entity from the political party that rules that state at any given time, a country may be ruled by a socialist party without the country itself claiming to be socialist or the socialist party being written into the constitution. This has occurred in both one-party and multi-party political systems. In particular, there are numerous cases of social democratic and democratic socialist parties winning elections in liberal democratic states and ruling for a number of terms until a different party wins the elections. While socialist parties have won many elections around the world and most elections in the Nordic countries, many of those countries have not adopted socialism as a state ideology or written the party into the constitution. Several countries with liberal democratic constitutions mention socialism. India is a liberal democracy that has been ruled by non-socialist parties on many occasions, but its constitution makes references to socialism. Certain other countries such as Croatia, Hungary, Myanmar, and Poland have constitutions that make references to their communist and socialist past by recognizing or condemning it, but without claiming to be socialist in the present.
  • 20.2K
  • 22 Nov 2022
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