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:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Tropospheric Ozone
Ozone (O3) is a trace gas of the troposphere, with an average concentration of 20–30 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas. Ozone is also an important constituent of the stratosphere, where the ozone layer exists which is located between 10 and 50 kilometers above the earths surface. The troposphere is the lowest layer of the Earth's atmosphere. It extends from the ground up to a variable height of approximately 14 kilometers above sea level. Ozone is least concentrated in the ground layer (or planetary boundary layer) of the troposphere. Ground level or tropospheric ozone is created by chemical reactions between oxides of nitrogen (NOx gases) and volatile organic compounds (VOCs). The combination of these chemicals in the presence of sunlight form ozone. Its concentration increases as height above sea level increases, with a maximum concentration at the tropopause. About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. Although tropospheric ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. Ozone in the troposphere is considered a greenhouse gas, and may contribute to global warming. Photochemical and chemical reactions involving ozone drive many of the chemical processes that occur in the troposphere by day and by night. At abnormally high concentrations (the largest source being emissions from combustion of fossil fuels), it is a pollutant, and a constituent of smog. Its levels have increased significantly since the industrial revolution, as NOx gasses & VOCs are some of the byproducts of combustion. With more heat and sunlight in the summer months, more ozone is formed which is why regions often experience higher levels of pollution in the summer months. Although the same molecule, ground level ozone can be harmful to our health, unlike stratospheric ozone that protects the earth from excess UV radiation. Photolysis of ozone occurs at wavelengths below approximately 310–320 nanometres. This reaction initiates the chain of chemical reactions that remove carbon monoxide, methane, and other hydrocarbons from the atmosphere via oxidation. Therefore, the concentration of tropospheric ozone affects how long these compounds remain in the air. If the oxidation of carbon monoxide or methane occur in the presence of nitrogen monoxide (NO), this chain of reactions has a net product of ozone added to the system.
  • 2.4K
  • 24 Nov 2022
Topic Review
Aquaculture Food Production in Portugal
World aquaculture food production rises every year, amounting, by 2018, to another all-time record of 82.1 million tonnes of farmed seafood, with Asia leading global production. In Europe, although coastal countries present historical fishing habits, aquaculture is in true expansion. Norway, the leading European producer, is the eighth main producer worldwide. Portugal is a traditional fishing country but has invested in the development of aquaculture for the past decade, attaining, by 2018, 13.3 tonnes produced, making Portugal the 16th main producer amongst European Union member states that year. Most Portuguese aquaculture facilities operate in coastal systems, resorting to extensive and semi-intensive rearing techniques. In Portugal, marine food production in transitional systems is particularly interesting as the practice has, worldwide, been continuously substituted by intensive methods. In fact, facilities in transitional systems have developed over time and products gained higher commercial value.
  • 2.4K
  • 18 Mar 2022
Topic Review
Power Generation in Sewage-Water Treatment Plants
Sewage-water treatment comprehends primary, secondary, and tertiary steps to produce reusable water after removing sewage contaminants. However, a sewage-water treatment plant is typically a power and energy consumer and produces high volumes of sewage sludge mainly generated in the primary and secondary steps. The use of more efficient anaerobic digestion of sewage water with sewage sludge can produce reasonable flowrates of biogas, which is shown to be a consolidated strategy towards the energy self-sufficiency and economic feasibility of sewage-water treatment plants. Anaerobic digestion can also reduce the carbon footprint of energy sources since the biogas produced can replace fossil fuels for electricity generation. 
  • 2.4K
  • 05 May 2022
Topic Review
Pine Ridge Indian Reservation
The Pine Ridge Indian Reservation (Template:Lang-lkt), also called Pine Ridge Agency, is an Oglala Lakota Native American reservation located in the U.S. state of South Dakota. Originally included within the territory of the Great Sioux Reservation, Pine Ridge was created by the Act of March 2, 1889, 25 Stat. 888. in the southwest corner of South Dakota on the Nebraska border. Today it consists of 3,468.85 sq mi (8,984.3 km2) of land area and is the eighth-largest reservation in the United States, larger than Delaware and Rhode Island combined. The reservation encompasses the entirety of Oglala Lakota County and Bennett County, the southern half of Jackson County, and a small section of Sheridan County added by Executive Order No. 2980 of February 20, 1904. Of the 3,142 counties in the United States, these are among the poorest. Only 84,000 acres (340 km2) of land are suitable for agriculture. The 2000 census population of the reservation was 15,521; but a study conducted by Colorado State University and accepted by the United States Department of Housing and Urban Development has estimated the resident population to reach 28,787. Pine Ridge is the site of several events that mark milestones in the history between the Sioux of the area and the United States (U.S.) government. Stronghold Table—a mesa in what is today the Oglala-administered portion of Badlands National Park—was the location of the last of the Ghost Dances. The U.S. authorities' attempt to repress this movement eventually led to the Wounded Knee Massacre on December 29, 1890. A mixed band of Miniconjou Lakota and Hunkpapa Sioux, led by Chief Spotted Elk, sought sanctuary at Pine Ridge after fleeing the Standing Rock Agency, where Sitting Bull had been killed during efforts to arrest him. The families were intercepted by a heavily armed detachment of the Seventh Cavalry, which attacked them, killing many women and children as well as warriors. This was the last large engagement between U.S. forces and Native Americans and marked the end of the western frontier. Changes accumulated in the last quarter of the 20th century; in 1971 the Oglala Sioux Tribe (OST) started Oglala Lakota College, a tribal college, which offers 4-year degrees. In 1973 decades of discontent at the Pine Ridge Reservation resulted in a grassroots protest that escalated into the Wounded Knee Incident, gaining national attention. Members of the Oglala Lakota, the American Indian Movement and supporters occupied the town in defiance of federal and state law enforcement in a protest that turned into an armed standoff lasting 71 days. This event inspired American Indians across the country and gradually led to changes at the reservation, with a revival of some cultural traditions. In 1981 the Lakota Tim Giago started the Lakota Times at Pine Ridge, the first independent Native American newspaper in the nation; he published it until selling it in 1998. Located at the southern end of the Badlands, the reservation is part of the mixed grass prairie, an ecological transition zone between the short-grass and tall-grass prairies; all are part of the Great Plains. A great variety of plant and animal life flourishes on and adjacent to the reservation, including the endangered black-footed ferret. The area is also important in the field of paleontology; it contains deposits of Pierre Shale formed on the seafloor of the Western Interior Seaway, evidence of the marine Cretaceous–Paleogene boundary, and one of the largest deposits of fossils of extinct mammals from the Oligocene epoch.
  • 2.3K
  • 07 Oct 2022
Topic Review
Geography and Cartography in Medieval Islam
Medieval Islamic geography and cartography refer to the study of geography and cartography in the Muslim world during the Islamic Golden Age (variously dated between the 8th century and 16th century). Muslim scholars made advances to the mapmaking traditions of earlier cultures, particularly the Hellenistic geographers Ptolemy and Marinus of Tyre,:193 combined with what explorers and merchants learned in their travels across the Old World (Afro-Eurasia). Islamic geography had three major fields: exploration and navigation, physical geography, and cartography and mathematical geography. Islamic geography reached its apex with Muhammad al-Idrisi in the 12th century.
  • 2.3K
  • 26 Oct 2022
Topic Review
Climate Change Maladaptation
Maladaptation is caused by adaptation that fails to reduce vulnerability or inadvertently increases it. Maladaptation can be defined as: ''maladaptation occurs when short-term strategies increase vulnerability in the long term'' or ''action taken ostensibly to avoid or reduce vulnerability to climate change that impacts adversely on, or increase the vulnerability of other systems, sectors, or social groups.''
  • 2.3K
  • 29 Mar 2021
Topic Review
Green and Blue Infrastructure
Green and blue infrastructure (GBI) is defined as a network of landscape components, which include green areas and water bodies. Such an infrastructure, available within an urban space, provides diverse environmental, economic, and social benefits to people and other living organisms.
  • 2.3K
  • 20 Aug 2021
Topic Review
Palm Oil Mill Effluent Treatment
POME is considered as one of the major problems that has generated voluminously from the palm oil industries. Pre-treatment is utmost required prior discharge to the environment. This review deals with current POME treatment techniques.
  • 2.3K
  • 26 May 2021
Topic Review
Triangulation Station
A triangulation station, also known as a triangulation pillar, trigonometrical station, trigonometrical point, trig station, trig beacon, or trig point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity. The nomenclature varies regionally: they are generally known as trigonometrical or triangulation stations in North America, trig points in the United Kingdom, trig pillars in Ireland, trig stations or points in Australia and New Zealand, and trig beacons in South Africa; triangulation pillar is the more formal term for the concrete columns found in the UK.
  • 2.3K
  • 02 Dec 2022
Topic Review
Stone Mountain
Stone Mountain is a quartz monzonite dome monadnock and the site of Stone Mountain Park near Stone Mountain, Georgia. At its summit, the elevation is 1,686 feet (514 m) above sea level and 825 feet (251 m) above the surrounding area. Stone Mountain is well known for not only its geology, but also the enormous rock relief on its north face, the largest bas-relief in the world. The carving depicts three Confederate figures, Jefferson Davis, Robert E. Lee and Stonewall Jackson, and has been the subject of widespread controversy. Stone Mountain was once owned by the Venable Brothers. It was purchased by the State of Georgia in 1958 "as a memorial to the Confederacy." Stone Mountain Park officially opened on April 14, 1965 – 100 years to the day after Lincoln's assassination, although the park had been in use for a few years. It is the most visited destination in the state of Georgia. Stone Mountain is more than 5 miles (8 km) in circumference at its base. The summit of the mountain can be reached by a walk-up trail on the west side of the mountain or by the Skyride aerial tram.
  • 2.3K
  • 04 Nov 2022
  • Page
  • of
  • 270
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
Video Production Service
Feedback