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Topic Review

Defect Types and Mechanism of Wind Turbine Blades

There are two main reasons for the damage to wind turbine blades. On the one hand, the wind turbine is in a harsh external environment, and the damage faults are directly caused by external factors, such as strong wind, rain or snow, salt fog, lightning strike, freezing, sandstorm, insects, etc. The other is the invisible defects caused by process problems in the technology of man-made manufacturing. These invisible defects are subject to repeated high loads and harsh external environments during the installation and operation of the wind turbine. The gradual expansion of invisible defects can lead to damage. Due to the complexity of the blade material and structure, each damage type may be caused by a combination of causes. Different defects in the production process and different operating conditions will cause different damage types.

9.9K
28 Sep 2022

Topic Review

A company's earnings before interest, taxes, depreciation, and amortization (commonly abbreviated EBITDA, pronounced /iːbɪtˈdɑː/, /əˈbɪtdɑː/, or /ˈɛbɪtdɑː/) is an accounting measure calculated using a company's earnings, before interest expenses, taxes, depreciation, and amortization are subtracted, as a proxy for a company's current operating profitability (i.e., how much profit it makes with its present assets and its operations on the products it produces and sells, as well as providing a proxy for cash flow). Though often shown on an income statement, it is not considered part of the Generally Accepted Accounting Principles (GAAP) by the SEC.

9.9K
08 Oct 2022

Topic Review

Degeneration Theory

Social degeneration was a widely influential concept at the interface of the social and biological sciences in the 18th and 19th centuries. During the 18th century, scientific thinkers including George Louis Leclerc, comte de Buffon, Johann Friedrich Blumenbach, and Immanuel Kant argued that humans shared a common origin but had degenerated over time due to differences in climate. This theory provided an explanation of where humans came from and why some people appeared different from others. In contrast, degenerationists in the 19th century feared that civilization might be in decline and that the causes of decline lay in biological change. These ideas derived from pre-scientific concepts of heredity ("hereditary taint") with Lamarckian emphasis on biological development through purpose and habit. Degeneration concepts were often associated with authoritarian political attitudes, including militarism and scientific racism, and a preoccupation with eugenics. The theory originated in racial concepts of ethnicity, recorded in the writings of such medical scientists as Johann Blumenbach and Robert Knox. From the 1850s, it became influential in psychiatry through the writings of Bénédict Morel, and in criminology with Cesare Lombroso. By the 1890s, in the work of Max Nordau and others, degeneration became a more general concept in social criticism. It also fed into the ideology of ethnic nationalism, attracting, among others, Maurice Barrès, Charles Maurras and the Action Française. Alexis Carrel, a French Nobel Laureate in Medicine, cited national degeneration as a rationale for a eugenics programme in collaborationist Vichy France. The meaning of degeneration was poorly defined, but can be described as an organism's change from a more complex to a simpler, less differentiated form, and is associated with 19th-century conceptions of biological devolution. In scientific usage, the term was reserved for changes occurring at a histological level – i.e. in body tissues. Although rejected by Charles Darwin, the theory's application to the social sciences was supported by some evolutionary biologists, most notably Ernst Haeckel and Ray Lankester. As the 19th century wore on, the increasing emphasis on degeneration reflected an anxious pessimism about the resilience of European civilization and its possible decline and collapse.

9.9K
21 Oct 2022

Topic Review

The Peshitta (Classical Syriac: ܦܫܝܛܬܐ‎ pšîṭtâ) is the standard version of the Bible for churches in the Syriac tradition. The consensus within biblical scholarship, though not universal, is that the Old Testament of the Peshitta was translated into Syriac from Hebrew, probably in the 2nd century AD, and that the New Testament of the Peshitta was translated from the Greek. This New Testament, originally excluding certain disputed books (2 Peter, 2 John, 3 John, Jude, Revelation), had become a standard by the early 5th century. The five excluded books were added in the Harklean Version (616 AD) of Thomas of Harqel. However, the 1905 United Bible Society Peshitta used new editions prepared by the Irish Syriacist John Gwynn for the missing books.

9.9K
08 Oct 2022

Topic Review

Declaration of War

A declaration of war is a formal act by which one state goes to war against another. The declaration is a performative speech act (or the signing of a document) by an authorized party of a national government, in order to create a state of war between two or more states. The legality of who is competent to declare war varies between nations and forms of government. In many nations, that power is given to the head of state or sovereign. In other cases, something short of a full declaration of war, such as a letter of marque or a covert operation, may authorise war-like acts by privateers or mercenaries. The official international protocol for declaring war was defined in the Hague Convention (III) of 1907 on the Opening of Hostilities. Since 1945, developments in international law such as the United Nations Charter, which prohibits both the threat and the use of force in international conflicts, have made declarations of war largely obsolete in international relations. The UN Security Council, under powers granted in articles 24 and 25, and Chapter VII of the Charter, may authorize collective action to maintain or enforce international peace and security. Article 51 of the United Nations (UN) Charter also states that: "Nothing in the present Charter shall impair the inherent right to individual or collective self-defence if an armed attack occurs against a state." Few nations have formally declared war upon another since then. In addition to this, non-state or terrorist organizations may claim to or be described as "declaring war" when engaging in violent acts. These declarations may have no legal standing in themselves, but they may still act as a call to arms for supporters of these organizations.

9.9K
11 Dec 2025

Topic Review

In science fiction and in the beliefs of ufology, a Venusian (/vɪˈnjuːʒən, -ʃən/) or Venerian is a native inhabitant of the planet Venus. Many science fiction writers have imagined what extraterrestrial life on Venus might be like.

9.9K
21 Oct 2022

Topic Review

Barcelona (/ˌbɑːrsəˈloʊnə/ BAR-sə-LOH-nə, Catalan: [bəɾsəˈlonə], Spanish: [baɾθeˈlona]) is a city in Spain . It is the capital and largest city of Catalonia, as well as the second most populous municipality of Spain. With a population of 1.6 million within city limits, its urban area extends to numerous neighbouring municipalities within the Province of Barcelona and is home to around 4.8 million people, making it the sixth most populous urban area in the European Union after Paris, London, Madrid, the Ruhr area and Milan. It is one of the largest metropolises on the Mediterranean Sea, located on the coast between the mouths of the rivers Llobregat and Besòs, and bounded to the west by the Serra de Collserola mountain range, the tallest peak of which is 512 metres (1,680 feet) high. Founded as a Roman city, in the Middle Ages Barcelona became the capital of the County of Barcelona. After merging with the Kingdom of Aragon, Barcelona continued to be an important city in the Crown of Aragon as an economic and administrative centre of this Crown and the capital of the Principality of Catalonia. Barcelona has a rich cultural heritage and is today an important cultural centre and a major tourist destination. Particularly renowned are the architectural works of Antoni Gaudí and Lluís Domènech i Montaner, which have been designated UNESCO World Heritage Sites. The headquarters of the Union for the Mediterranean are located in Barcelona. The city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments. Barcelona is one of the world's leading tourist, economic, trade fair and cultural centres, and its influence in commerce, education, entertainment, media, fashion, science, and the arts all contribute to its status as one of the world's major global cities. It is a major cultural and economic centre in southwestern Europe, 24th in the world (before Zürich, after Frankfurt) and a financial centre. In 2008 it was the fourth most economically powerful city by GDP in the European Union and 35th in the world with GDP amounting to €177 billion. In 2012 Barcelona had a GDP of $170 billion; and it was leading Spain in employment rate in that moment. In 2009 the city was ranked Europe's third and one of the world's most successful as a city brand. In the same year the city was ranked Europe's fourth best city for business and fastest improving European city, with growth improved by 17% per year, and the city has been experiencing strong and renewed growth for the past three years. Since 2011 Barcelona has been a leading smart city in Europe. Barcelona is a transport hub, with the Port of Barcelona being one of Europe's principal seaports and busiest European passenger port, an international airport, Barcelona–El Prat Airport, which handles over 40 million passengers per year, an extensive motorway network, and a high-speed rail line with a link to France and the rest of Europe.

9.9K
16 Nov 2022

Topic Review

Iranian Plateau

The Iranian Plateau or the Persian Plateau is a geological feature in Central Asia, South Asia, and Western Asia. It is the part of the Eurasian Plate wedged between the Arabian and Indian plates, situated between the Zagros Mountains to the west, the Caspian Sea and the Kopet Dag to the north, the Armenian Highlands and the Caucasus Mountains in the northwest, the Strait of Hormuz and the Persian Gulf to the south and the Indo-Gangetic Plain to the east in Indian subcontinent. As a historical region, it includes Parthia, Media, Persis, the heartlands of Iran and some of the previous territories of Greater Iran. The Zagros Mountains form the plateau's western boundary, and its eastern slopes may be included in the term. The Encyclopædia Britannica excludes "lowland Khuzestan" explicitly and characterizes Elam as spanning "the region from the Mesopotamian Plain to the Iranian Plateau". From the Caspian in the northwest to Balochistan in the south-east, the Iranian Plateau extends for close to 2,000 km. It encompasses the greater part of Iran, all of Afghanistan, and Pakistan west of the Indus River containing some 3,700,000 square kilometres (1,400,000 sq mi). In spite of being called a "plateau", it is far from flat but contains several mountain ranges, the highest peak being Damavand in the Alborz at 5610 m, and the Dasht-e Lut east of Kerman in Central Iran falling below 300 m.

9.9K
22 Nov 2022

Topic Review

Popular Culture

Popular culture refers to the set of ideas, practices, images, and phenomena that are prevalent and widely accepted within a society at a given point in time. It encompasses various aspects of daily life, including entertainment, fashion, music, sports, and technology, reflecting the shared interests and preferences of the general public. Popular culture is dynamic and evolves over time, influenced by social, political, and technological developments, making it a key area of study within the realm of social science.

9.8K
25 Jan 2024

Topic Review

Methods of Residual Stress Measurement

This entry introduces several commonly used residual stress measurement methods.

9.8K
01 Nov 2020

Topic Review

Sensor Technology in Autonomous Vehicles

With the significant advancement of sensor and communication technology and the reliable application of obstacle detection techniques and algorithms, automated driving is becoming a pivotal technology that can revolutionize the future of transportation and mobility. Sensors are fundamental to the perception of vehicle surroundings in an automated driving system, and the use and performance of multiple integrated sensors can directly determine the safety and feasibility of automated driving vehicles.

9.8K
31 Mar 2021

Topic Review

Collagen is the major fibrillar protein in most living organisms. Among the different types of collagen, type I collagen is the most abundant one in the tissues of marine invertebrates. The present overview has focused on a brief history of collagen, basic structure and synthesis, nomenclature, types, and classifications, sources of collagen with the emphasis on sea cucumber collagen, and related functional properties.

9.8K
13 Oct 2020

Topic Review

Performance Comparison of SQL and Graph Databases

In developing NoSQL databases, a major motivation is to achieve better efficient query performance compared with relational databases. The graph database is a NoSQL paradigm where navigation is based on links instead of joining tables. Links can be implemented as pointers, and following a pointer is a constant time operation, whereas joining tables is more complicated and slower, even in the presence of foreign keys. Therefore, link-based navigation has been seen as a more efficient query approach than using join operations on tables. Existing studies strongly support this assumption. Query complexity has received less attention. For example, in enterprise information systems, queries are usually complex so data need to be collected from several tables or by traversing paths of graph nodes of different types.

9.8K
15 Jul 2022

Topic Review Video

Ecological Stoichiometry

Ecological stoichiometry considers how nutritional needs of organisms for basic body-building molecules shape their ecology. It asks how nutritional demands of organisms and supply of nutrients in their environments affects organisms growth, their interactions with the biotic and abiotic worlds and nutrient cycling in whole ecosystem.

9.8K
04 Nov 2020

Topic Review

The Heritage Foundation

The Heritage Foundation (abbreviated to Heritage) is an American conservative think tank based in Washington, D.C., primarily geared towards public policy. The foundation took a leading role in the conservative movement during the presidency of Ronald Reagan, whose policies were taken from Heritage's policy study Mandate for Leadership. Since then, The Heritage Foundation has continued to have a significant influence in U.S. public policy making, and is considered to be one of the most influential conservative public policy organizations in the United States .

9.8K
07 Nov 2022

Topic Review

IQ and the Wealth of Nations

IQ and the Wealth of Nations is a 2002 book by psychologist Richard Lynn and political scientist Tatu Vanhanen. The authors argue that differences in national income (in the form of per capita gross domestic product) are correlated with differences in the average national intelligence quotient (IQ). They further argue that differences in average national IQs constitute one important factor, but not the only one, contributing to differences in national wealth and rates of economic growth. The book has drawn widespread criticism from other academics. Critiques have included questioning of the methodology used, the incompleteness of the data, and the conclusions drawn from the analysis. The 2006 book IQ and Global Inequality is a follow-up to IQ and the Wealth of Nations by the same authors.

9.8K
14 Oct 2022

Topic Review

Lithium Recovery via Chemical Precipitation

Lithium is a vital raw material used for a wide range of applications, such as the fabrication of glass, ceramics, pharmaceuticals, and batteries for electric cars. The accelerating electrification transition and the global commitment to decarbonization have caused an increasing demand for lithium. The current supply derived from brines and hard rock ores is not enough to meet the global demand unless alternate resources and efficient techniques to recover this valuable metal are implemented.

9.8K
21 Feb 2023

Topic Review

Biopolymers for Medical Applications

Biopolymers are the organic substances present in natural sources. The term biopolymer originates from the Greek words bio and polymer, representing nature and living organisms. Large macromolecules made up of numerous repeating units are known as biopolymers. As per the IUPAC definition, a macromolecule defines a single molecule. The biopolymers are found to be biocompatible and biodegradable, making them useful in different applications, such as edible films, emulsions, packaging materials in the food industry, and as drug transport materials, medical implants like medical implants organs, wound healing, tissue scaffolds, and dressing materials in pharmaceutical industries.

9.8K
18 Mar 2022

Topic Review

Angle-Resolved Photoemission Spectroscopy (ARPES)

Angle-resolved photoemission spectroscopy (ARPES) is a vital technique in which spectra are collected from both the energy and momentum of photoemitted electrons and is indispensable for investigating the electronic band structure of solids.

9.8K
08 Dec 2020

Topic Review

Extraction Methods of Medicinal Plants for Antimicrobial Textiles

Medicinal plants are the product of natural drug discoveries and have gained traction due to their pharmacological activities. Pathogens are everywhere, and they thrive in ideal conditions depending on the nutrients, moisture, temperature, and pH that increase the growth of harmful pathogens on surfaces and textiles.

9.8K
22 Aug 2022

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