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:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Elastic Modulus
Elastic modulus (E) is a key parameter in predicting the ability of a material to withstand pressure and plays a critical role in the design of rock engineering projects. E has broad applications in the stability of structures in mining, petroleum, geotechnical engineering, etc. E can be determined directly by conducting laboratory tests, which are time consuming, and require high-quality core samples and costly modern instruments. Thus, devising an indirect estimation method of E has promising prospects.
  • 1.3K
  • 25 Mar 2022
Topic Review
Dryland Food Security in Ethiopia
Global drylands are expanding due to climate change, threatening global food security (FS), especially in Africa. Eastern Africa has 328 million hectares of drylands, 6% of which is covered by crops; most crops are rained on, and irrigated land accounts for only 5 million hectares (22%). In Ethiopia, 75% of the landmass is categorized as dryland, the majority of which experiences high risks of land degradation, natural hazards, and water and food shortages.
  • 1.3K
  • 28 Jun 2021
Topic Review
Mechanisms and Impact of Biofilms
Biofilms comprising aggregates of microorganisms or multicellular communities have been a major issue as they cause resistance against antimicrobial agents and biofouling. To date, numerous biofilm-forming microorganisms have been identified, which have been shown to result in major effects including biofouling and biofilm-related infections. Quorum sensing (which describes the cell communication within biofilms) plays a vital role in the regulation of biofilm formation and its virulence. As such, elucidating the various mechanisms responsible for biofilm resistance (including quorum sensing) will assist in developing strategies to inhibit and control the formation of biofilms in nature. Employing biological control measures (such as the use of bioactive compounds) in targeting biofilms is of great interest since they naturally possess antimicrobial activity among other favorable attributes and can also possibly act as potent antibiofilm agents.
  • 1.3K
  • 13 Oct 2021
Topic Review
3D Printed Electromagnetic Vibration Harvesters
Energy harvesting is the utilisation of ambient energy in order to power electronics such as wireless sensor nodes (WSN) or wearables without the need of batteries. This allows to operate the node over a much longer time period compared to battery-powered devices along with lower maintenance efforts. Furthermore, the low-maintenance requirements allow to operate these WSNs in environments with limited or no accessibility.
  • 1.3K
  • 05 Nov 2021
Topic Review
Snowmelt Models
The snowmelt model is a hydrological model that simulates the processes of snow accumulation, melt, and confluence. Since the snowmelt process involves the complex energy transfer and water transfer processes between the atmosphere and snow, between different snow layers, and between snow layers and soil, it is more complicated than the formation process of rainfall runoff. If there is a rainfall event on snow, it is very difficult to simulate the runoff generation process due to the mixture of rain and snow. Snowmelt simulation is the basis for the simulation of snowmelt flood formation processes, and it plays a crucial role in accurately modelling snowmelt floods.
  • 1.3K
  • 29 Oct 2021
Topic Review
Acoustic Emission Spectroscopy
Acoustic emission (AE) spectroscopy has become the method of choice in many fieldsbecause it is highly sensitive. For example, the AE system constructed by the Vallen company, Germany, has a sampling rate that can reach up to 10 MHz, an arrival time resolution of 100 ns, and an energy resolution of 1.8 × 10−18V2s (i.e., in the attojoule regime, aJ) referred to sensor signal at 34 dB preamplifier gain.
  • 1.2K
  • 28 Oct 2021
Topic Review
Nomenclature for Hydrogeological Instability Risks
The nomenclature for hydrogeological instability risks includes four main risks, which are distinguished according to the risk causes : 1) hydrogeological risk, that is slowly caused by natural factors (e.g. collapse landslides in a calcareous cliff in uninhabited areas and erosion along a marly-calcareous slope) in environments where human activities are minimal, i.e. woods, forests and mountain pastures; 2) hydraulic-pedological farming risk, that implies the occurrence of landslides in every winter and is caused by incorrect crop selection, not suitable for the soil and climate parameters (e.g. on a hilly slope with a clay vertisol type with a landslide having different fronts, when the arable land is cultivated with a cereal-legume crop rotation), or the presence of springs with missing drainage in clay soils with a high gradient;3) hydraulic-infrastructural risk, that is caused by the building up of infrastructures not suitable for the surrounding environment, as they change the downflow of shallow water; 4) hydraulic-infrastructural-pedological-management risk, that is caused by crop operations not suitable for soil and crop parameters, where the selected cultivated plant species are suitable for the environment and field improvements change water downflow (e.g. in soils along hilly calcarenite slopes cultivated with olive orchards, where up-down soil tillage causes shallow water erosion).
  • 1.2K
  • 25 Jan 2022
Topic Review
Biomass Combustion in Chile
Chile is a country that is highly dependent on importing energy, particularly fossil hydrocarbons, even though it possesses a variety of energy resources that are relatively well distributed. Around 24% of the country’s power grid comes from forest-based biomass, with firewood being the most-used energy source, mainly for heating and cooking purposes: 97% of firewood is used for heating, and the other 3% is used for domestic water heating and, in some cases, for cooking food. Given that firewood is used by thousands of people during the year, wood burning has had severe social and environmental consequences in densely populated cities such as Temuco. These consequences are mainly due to biomass combustion, which is an important source of particulate matter stemming from the incomplete combustion of components like cellulose, hemicellulose, and lignin, in addition to temperature-produced changes caused by combustion from uncontrolled sources. 
  • 1.1K
  • 06 Jul 2021
Topic Review
Salt Stress in Plants
Salinization of soils and freshwater resources by natural processes and/or human activities has become an increasing issue that affects environmental services and socioeconomic relations. In addition, salinization jeopardizes agroecosystems, inducing salt stress in most cultivated plants (nutrient deficiency, pH and oxidative stress, biomass reduction), and directly affects the quality and quantity of food production. Depending on the type of salt/stress (alkaline or pH-neutral), specific approaches and solutions should be applied to ameliorate the situation on-site.
  • 1.1K
  • 23 Mar 2022
Topic Review
Temperature and Root System of Two Lupine Species
The aim of this entry was to assess the effect of elevated temperature on the growth, morphology and spatial orientation of lupine roots at the initial stages of development and on the formation of lupine root architecture at later stages. Two lupine species were studied—the invasive Lupinus polyphyllus Lindl. and the non-invasive L. luteus L. The plants were grown in climate chambers under 25 °C and simulated warming at 30 °C conditions. The angle of root curvature towards the vector of gravity was measured at the 48th hour of growth, and during a 4-h period after 90° reorientation. Root biometrical, histological measurements were carried out on 7-day-old and 30-day-old plants. The elevation of 5 °C affected the root formation of the two lupine species differently. The initial roots of L. polyphyllus were characterized by worse spatial orientation, reduced growth and reduced mitotic index of root apical meristem at 30 °C compared with 25 °C. The length of primary roots of 30-day-old lupines and the number of lateral roots decreased by 14% and 16%, respectively. 
  • 1.1K
  • 18 Jan 2022
Topic Review
The Water–Energy–Food Nexus Index
The water–energy–food (WEF) Nexus Index is a quantitative measure and representation of country-level WEF security based on 21 water, energy, and food security indicators. The WEF nexus has emerged as a leading tool for assessing integrated resource management strategies and for monitoring progress towards the WEF-related Sustainable Development Goals. A notable outcome of WEF nexus research has been the calculation of the global WEF Nexus Index, which provides a quantitative ranking of country-level WEF security for 170 nations.
  • 1.0K
  • 11 Feb 2022
Topic Review
Development Environments and Factors of Subsidence Dolines
On covered karsts, the frequent and rapid development of subsidence dolines result in the striking change of surface conditions and this process may cause a significant damage to man-made constructions. According to current scientific knowledge, a prediction on the development of subsidence dolines and their development sites, by which the damage could be reduced to a great extent, is not possible yet. Based on literary data, in this study, development environments and impacts are described that affect subsidence doline development and the site of development. Point of views are suggested for predicting the development and development sites.
  • 1.0K
  • 11 Jan 2022
Topic Review
Epithelial Cells in Environmental-Associated Airway Diseases
People are exposed to contaminants through the respiratory tract and skin; they first reach the bloodstream and, subsequently, the organs, causing more or less serious damage to health. Thus, the effects of atmospheric pollution affect the respiratory tract with acute symptoms and the circulatory system with cardiovascular events, leading to hospitalizations and mortality. In addition to the acute effects, long-term effects can also be had, including an alteration of lung function in adults, children, and adolescents. Specifically, in children and adolescents, chronic exposure to air pollution is associated with a reduction in forced vital capacity (FVC), which correlates with age and can be interpreted as a reduction in the lung growth and respiratory function of the lower airways. Children, together with elderly persons, are the most sensitive subjects to environmental pollution; to these are added subjects with chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Emerging contaminants induce pulmonary toxicity by promoting an inflammatory response in lung epithelial cells.
  • 1.0K
  • 15 Mar 2022
Topic Review
Fertilization and Soil Microbial Community
Crop production is currently expanding globally due to an increased demand for food, animal feed and biofuels; the latter has been stimulated by the increase in oil prices making bioenergy crops more competitive and profitable compared to fossil fuels. Chemical fertilizers (also termed mineral, inorganic or synthetic fertilizers) contain a high concentration of a primary nutrient (nitrogen, N; potassium, K; phosphorous, P) as inorganic salts. Secondary elements (calcium, magnesium and sulfur) can also be added to soil by chemical fertilizers. Micronutrients (boron, manganese, iron, zinc, copper, molybdenum, cobalt and chlorine) are in general absent in NPK chemical fertilizers and can be supplied by specific synthetic and expensive plant nutrients with soil or foliar applications. Soil microbes have different responses to fertilization based on differences in the total carbon (C), nitrogen (N) and phosphorus (P) contents in the soil, along with soil moisture and the presence of plant species.
  • 1.0K
  • 11 Mar 2022
Topic Review
A city Multi-Floor Manufacturing Cluster
Multi-floor manufacturing cluster (MFMC) comprise production and service enterprises of various types of ownership, mainly SMEs, with different production orientations, with the presence of small-scale in-house equipment. This feature of MFMC promotes business competition, allowing for creating collaborative and networked organizations that can happen at some stages of development and can reach a level of a virtual manufacturing network based on Digital Twins models to fulfil customer orders.
  • 962
  • 28 Mar 2022
Topic Review
Recovery of Rare Earth Elements
Rare earth elements (REEs) as defined by the International Union of Pure and Applied Chemistry (IUPAC) include metals characterized by similar properties, namely scandium (Sc), yttrium (Y) and all the lanthanides. The latter correspond to the chemical elements listed in the periodic table of Mendeleev that have an atomic number ranging from 57 for lanthanum (La) to 71 for lutetium (Lu). REEs are often subdivided into “light rare earths elements” (LREEs) and “heavy rare earths elements” (HREEs) according to their atomic numbers. Yttrium is oftentimes associated with HREEs due to chemical similarities, including ionic radii. In some cases, the elements from samarium to terbium are considered as the “middle rare earth elements” (MREEs). 
  • 959
  • 03 Aug 2021
Topic Review
Conventional Event Tree Analysis on Liquefied Natural Gas
Liquefied natural gas (LNG) is stored in facilities located in urban areas and transported over public roads. A shift towards the broader use of LNG is economically and environmentally justified. Conventional event trees for LNG emergency release in three different units is a concept that is based on the physical and chemical properties of LNG. It has been designed with deep consideration and analysis of past experiences and real cases of LNG incidents. The idea of having training checkpoints, such as ‘decision points’ and ‘learning curve points’ in the continuum of a training or exercise enable the achievement of optimal learning objectives in a flexible way which take into account the trainee individual mental and physical disposition on a day, scalability of difficulty level as well as realistic scenario paths determined by the performance of the trainees facing concrete operational problems.
  • 937
  • 07 Mar 2022
Topic Review
Urban Heat Island Analysis
Urban Heat Island （UHI ) studies have been conducted for over 200 years, since the first conceptualization by Luke Howard in 1818. Generally, an urban heat island (UHI) is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas because of human activities. The temperature difference is usually greater at night than during the day and is most apparent when winds are weak.
  • 920
  • 08 Dec 2021
Topic Review
Integration of Environmental Justice and Sustainability in Practice
The environmental justice (EJ) movement has been a key factor in the United States’ struggle to provide a healthy environment for all to thrive. The origins of the movement date as far back as the 1960’s, led primarily by people of color and low economic status communities living in America’s most polluted environments. More recently, the just sustainability movement calls for the inclusion of EJ considerations, including social justice, equity, and human rights, into sustainability science and initiatives.
  • 918
  • 13 Jan 2022
Topic Review
Methods of Thermal Treatment of Radioactive Waste
Nuclear power is generated by a small amount of fuel, as related to other non-renewable energy sources. The volume of waste formed in this process is comparably small. Thermal treatment of waste is a term given to any treatment technology that involves high temperatures in the processing of the waste feedstock. All the thermal treatment methods used for normal waste have been applied to radioactive waste.  
  • 918
  • 24 Jan 2022
  • Page
  • of
  • 6
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
ScholarVision Creations
Feedback