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Topic Review
Pole Shift Hypothesis
The cataclysmic pole shift fringe theory suggests that there have been geologically rapid shifts in the relative positions of the modern-day geographic locations of the poles and the axis of rotation of the Earth, creating calamities such as floods and tectonic events. There is evidence of precession and changes in axial tilt, but this change is on much longer time-scales and does not involve relative motion of the spin axis with respect to the planet. However, in what is known as true polar wander, the solid Earth can rotate with respect to a fixed spin axis. Research shows that during the last 200 million years a total true polar wander of some 30° has occurred, but that no super-rapid shifts in the Earth's pole were found during this period. A characteristic rate of true polar wander is 1° or less per million years. Between approximately 790 and 810 million years ago, when the supercontinent Rodinia existed, two geologically rapid phases of true polar wander may have occurred. In each of these, the magnetic poles of the Earth shifted by approximately 55°.
  • 8.4K
  • 10 Oct 2022
Topic Review
Plasma technology water purification
Plasma technology water purification is a new water treatment technology developed according to the trend of industrial water use in the 21st century. It is effective, efficient, scalable, versatile and customizable. These technologies must be able to adapt to new contaminants, reduce energy consumption, maintain or improve the proportionality between power and flow, demonstrate various flow capacities, minimize the transformation of existing infrastructure, prepare for imminent regulations, and tailor chemistry to site-specific requirements. New methods of water treatment by plasma must have all the above-mentioned properties and pose the least risk to public health. NTAPPs and their chemical reactions release energy and reactive chemical species that can kill bacteria and microorganisms, resulting in the disinfection of water. The advantage of this technique is that it can be performed in ambient air under atmospheric pressure without a vacuum system. Furthermore, NTAPP does not involve chemical products such as Cl. NTAPP can be used for water treatment in three ways: via direct, indirect, and bubbling methods.
  • 7.9K
  • 10 Jun 2021
Topic Review
DPSIR Model
       The Driving force – Pressure – Status – Impact - Response (DPSIR) framework has been widely used in literature to analyse environmental problems. The DPSIR facilitates the investigation of all the possible cause-effect relationships and to plan appropriate technological responses.  This contribution shows an application of the DPSIR to the remediation of contaminated sites, exploiting the case study of the Mar Piccolo di Taranto (Southern Italy). Methodologically, several references were considered, whose information was classified according to the logical scheme of the DPSIR. Among the results it is interesting to observe how, due to its natural hydrogeological network conformation, the Mar Piccolo represents the final receptor of pollutants from industrial, anthropic and agricultural activities. The mobility of contaminants from sediments to the water column and the subsequent bioaccumulation into marine organisms pose a serious threat of unacceptable magnitude to human safety. Responses may concern restriction of area use, control of pollution fonts as well as the implementation of suitable contaminated marine sediment remediation measures. It is noted that the preliminary organization of the existing data can lead to the development of a DPSIR-based Environmental Decision Support System (EDSS). 
  • 7.7K
  • 30 Oct 2020
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.
  • 7.7K
  • 03 Nov 2022
Topic Review
Rainfall Data
As is widely recognized, rainfall data is necessary for the mathematical modelling of extreme hydrological events, such as droughts or floods, as well as for evaluating surface and subsurface water resources and their quality. The phase, quantity, and elevation of generic hydrometeors in the atmosphere can be estimated by ground-based radars. Satellites can provide images with visible and infrared radiation, and they can also serve as platforms for radiometers to derive the quantity and phase of hydrometeors. Radars and satellites provide spatial information on precipitation at wide scales, avoiding many problems connected to local ground measurements, including those for the areal inhomogeneity of a network. However, direct rainfall observations at point scale can be obtained only by rain gauges installed at the soil surface.
  • 7.7K
  • 29 Jan 2022
Topic Review
Bearing (Navigation)
In navigation, bearing is the horizontal angle between the direction of an object and another object, or between it and that of true north.
  • 7.5K
  • 05 Dec 2022
Topic Review
Water Literacy
Water literacy may be considered generally as the culmination of water-related knowledge, attitudes and behaviors.  It holds growing importance for sustainable water resource use and management.  While use and definitions of the concept of water literacy vary broadly in the literature, the synthesis of these identifies common elements and themes in a holistic framework.
  • 7.5K
  • 03 Feb 2022
Topic Review
Soil Bioremediation
Petroleum hydrocarbons, heavy metals and agricultural pesticides have mutagenic, carcinogenic, immunotoxic and teratogenic effects and cause drastic changes in soil physicochemical and microbiological characteristics, thereby representing a serious danger to health and environment. Therefore, soil pollution urgently requires the application of a series of physicochemical and biological techniques and treatments to minimize the extent of damage. Among them, bioremediation has been shown to be an alternative that can offer an economically viable way to restore polluted areas.
  • 7.5K
  • 27 Oct 2020
Topic Review
Plastic Sand as a Construction Material
Plastic waste pollution poses a serious environmental concern. At the same time, the cement industry is among the biggest sources of CO2 emissions, which poses another environmental challenge. Plastic sand bricks could be a workable solution for combating issues related to solid waste. The compressive strength decreased with increasing ratios of plastic to sand. Plastic sand bricks weighed less than the conventional bricks.
  • 7.4K
  • 10 Jun 2022
Topic Review
Ground-Penetrating Radar in Soil Studies
Information on the spatiotemporal variability of soil properties and states within the agricultural landscape is vital to identify management zones supporting precision agriculture (PA). Ground-penetrating radar (GPR) and electromagnetic induction (EMI) techniques have been applied to assess soil properties, states, processes, and their spatiotemporal variability. 
  • 7.3K
  • 14 Jun 2023
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