Log in/Sign up
Arts & Humanities
Biology & Life Sciences
Business & Economics
Chemistry & Materials Science
Computer Science & Mathematics
Environmental & Earth Sciences
Medicine & Pharmacology
Public Health & Healthcare
Uranyl Carbonate Minerals
Uranyl carbonates are one of the largest groups of secondary uranium(VI)-bearing natural phases being represented by 40 minerals approved by the International Mineralogical Association, overtaken only by uranyl phosphates and uranyl sulfates. Uranyl carbonate phases form during the direct alteration of primary U ores on contact with groundwaters enriched by CO2, thus playing an important role in the release of U to the environment. The presence of uranyl carbonate phases has also been detected on the surface of “lavas” that were formed during the Chernobyl accident.
24 Jun 2021
Conductive Heat Transfer in Thermal Bridges
A thermal bridge is a component of a building that is characterized by a higher thermal loss compared with its surroundings. Their accurate modeling is a key step in energy performance analysis due to the increased awareness of the importance of sustainable design. Thermal modeling in architecture and engineering is often not carried out volumetrically, thereby sacrificing accuracy for complex geometries, whereas numerical textbooks often give the finite element method in much higher generality than required, or only treat the case of uniform materials. Despite thermal modeling traditionally belonging exclusively to the engineer’s toolbox, computational and parametric design can often benefit from understanding the key steps of finite element thermal modeling, in order to inform a real-time design feedback loop. In this entry, these gaps are filled and the reader is introduced to all relevant physical and computational notions and methods necessary to understand and compute the stationary energy dissipation and thermal conductance of thermal bridges composed of materials in complex geometries. The overview is a self-contained and coherent expository, and both physically and mathematically as correct as possible, but intuitive and accessible to all audiences. Details for a typical example of an insulated I-beam thermal bridge are provided.
26 May 2022
Effect of Sanitizing Treatments on Respirator Filtration Performance
Disposable respirator masks with an accepted performance rating are seriously compromised from an exposure to saturated alcoholic vapours, can tolerate a one-off spray treatment with an alcoholic solution and retain their attested protection under the influence of alcoholic vapours from the use of hand sanitizer or spray sanitizer.
10 Jan 2022
Methanol to Gasoline (MTG)
The MTG (Methanol to Gasoline) process allows us to transform methanol into hydrocarbons within the range of gasoline boiling points.
04 Mar 2022
Catalytic Mechanism of Photocatalysts Based on GCN Heterogeneous
In the current world situation, population and industrial growth have become major problems for energy and environmental concerns. Extremely noxious pollutants such as heavy metal ions, dyes, antibiotics, phenols, and pesticides in water are the main causes behind deprived water quality leading to inadequate access to clean water. In this connection, graphite carbon nitride (GCN or g-C3N4) a nonmetallic polymeric material has been utilized extensively as a visible-light-responsive photocatalyst for a variety of environmental applications.
16 Jun 2022
A literature survey revealed that GeSn materials have numerous potential applications, including Si-based, integrated high-efficiency light sources; high-mobility electronic devices; low-cost Si-based high-performance shortwave infrared (SWIR) imaging sensors; Si-based photovoltaics; optical signal encoding in the mid-infrared range; high-performance logic applications; Si-based integrated thermoelectrics as wearable devices; Si-based spintronics; Si-based integrated reconfigurable dipoles; and Si-based quantum computing. GeSn-related fundamental research and development applications have also been extensively investigated.
14 Mar 2022
Metal-Organic Frameworks in CO2 Cycloaddition with Epoxides
The level of carbon dioxide in the atmosphere is growing rapidly due to fossil fuel combustion processes, heavy oil, coal, oil shelter, and exhausts from automobiles for energy generation, which lead to depletion of the ozone layer and consequently result in global warming. The realization of a carbon-neutral environment is the main focus of science and academic researchers of today. Several processes were employed to minimize carbon dioxide in the air, some of which include the utilization of non-fossil sources of energy like solar, nuclear, and biomass-based fuels. Consequently, these sources were reported to have a relatively high cost of production and maintenance. The applications of both homogeneous and heterogeneous processes in carbon capture and storage were investigated in recent years and the focus now is on the conversion of CO2 into useful chemicals and compounds. It was established that CO2 can undergo cycloaddition reaction with epoxides under the influence of special catalysts to give cyclic carbonates, which can be used as value-added chemicals at a different level of pharmaceutical and industrial applications. Among the various catalysts studied for this reaction, metal-organic frameworks are now on the frontline as a potential catalyst due to their special features and easy synthesis. Several metal-organic framework (MOF)-based catalysts were studied for their application in transforming CO2 to organic carbonates using epoxides. Here, we report some recent studies of porous MOF materials and an in-depth discussion of two repeatedly used metal-organic frameworks as a catalyst in the conversion of CO2 to organic carbonates
25 Nov 2021
MXenes—A New Class of Two-Dimensional Materials
A new class of two-dimensional nanomaterials, MXenes, which are carbides/nitrides/carbonitrides of transition and refractory metals, has been critically analyzed. Since the synthesis of the first family member in 2011 by Yury Gogotsi and colleagues, MXenes have quickly become attractive for a variety of research fields due to their exceptional properties. Despite the fact that this new family of 2D materials was discovered only about ten years ago, the number of scientific publications related to MXene almost doubles every year. Thus, in 2021 alone, more than 2000 papers are expected to be published, which indicates the relevance and prospects of MXenes.
28 Mar 2022
Calcium Silicate-Based Materials - Antimicrobial
Endodontic materials have significantly improved dental treatment techniques in several aspects as they can be used for vital pulp treatments, as temporary root canal medication, in definitive fillings, in apical surgeries, and for regenerative procedures. Calcium silicate-based cement is a class of dental material that is used in Endodontics in direct contact with the dental structures, connective tissue, and bone. Because the material interacts with biological tissues and stimulates biomineralization processes, its properties are of major importance. The main challenge in endodontic treatments is the elimination of biofilms that are present in the root canal system anatomical complexities, as it remains even after chemical-mechanical preparation and disinfection procedures. Thus, an additional challenge for these biomaterials is to exert antimicrobial activity while maintaining their biological properties in parallel.
29 Jul 2021
Hypopigmentation Mechanisms of Anti-Tyrosinase Peptides from Food Proteins
Skin hyperpigmentation resulting from excessive tyrosinase expression has long been a problem for beauty lovers, which has not yet been completely solved. Although researchers are working on finding effective tyrosinase inhibitors, most of them are restricted, due to cell mutation and cytotoxicity. Therefore, functional foods are developing rapidly for their good biocompatibility. Food-derived peptides have been proven to display excellent anti-tyrosinase activity, and the mechanisms involved mainly include inhibition of oxidation, occupation of tyrosinase’s bioactive site and regulation of related gene expression. For anti-oxidation, peptides can interrupt the oxidative reactions catalyzed by tyrosinase or activate an enzyme system, including super-oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) to scavenge free radicals that stimulate tyrosinase. In addition, researchers predict that peptides probably occupy the site of the substrate by chelating with copper ions or combining with surrounding amino acid residues, ultimately inhibiting the catalytic activity of tyrosinase.
06 May 2022
Featured Entry Collections
Encyclopedia of Social Sciences
Encyclopedia of ZEMCH Research and Development
Encyclopedia of Engineering
Encyclopedia of Piezoelectrics
Log in/Sign up
Terms and Conditions
Browse our user manual, common Q&A, author guidelines, etc.
Rate your experience
Let us know your experience and what we could improve.
Report an error
Is something wrong? Please let us know!
Other feedback you would like to report.
Did you find what you were looking for?
Do you agree to share your valuable feedback publicly on
Yes, I agree. Encyclopedia can post it.
No, I do not agree. I would not like to post my testimonial.
Upload a screenshot
(Max file size 2MB)