Topic Review
Chemical looping
Chemical looping technology in general, is the rising star in chemical technologies, which is capable of low CO2 emissions with applications in the production of heat, fuels, chemicals, and electricity. This entry discusses the technology in general, gives an overview of some pilot scale plants and the different chemical looping processes with focus on the production of heat and chemicals, highlights the importance of the development of oxygen carrier materials with suitable properties, 2.11.0.0 2.11.0.0
  • 2.9K
  • 02 Nov 2020
Topic Review
Unbibium
Unbibium /uːnˈbɪbiəm/, also known as eka-thorium or simply element 122, is the currently hypothetical chemical element in the periodic table with the placeholder symbol of Ubb and atomic number 122. Unbibium and Ubb are the temporary systematic IUPAC name and symbol respectively, until a permanent name is decided upon. In the periodic table of the elements, it is expected to follow unbiunium as the second element of the superactinides, or the g-block and the fourth element of the 8th period. It has attracted recent attention, for similarly to unbiunium, it is expected to fall within the range of the island of stability. Despite many attempts, unbibium has not yet been synthesized, and therefore no natural isotopes have been found to exist. It is currently predicted that it has a g-orbital, the second element of which to have such besides unbiunium, which also has yet to be synthesized. It will most likely require nuclear fission to be produced artificially. In 2008, it was claimed to have been discovered in natural thorium samples but that claim has now been dismissed by recent repetitions of the experiment using more accurate techniques.
  • 2.7K
  • 29 Nov 2022
Topic Review
Shape-Memory Polymers in Dentistry
Objective: To perform a systematic review (SR) of existing literature and a patent landscape report (PLR) regarding the potential applications of shape-memory polymers (SMPs) in dentistry. Search strategy: Clinical and Biomedical online databases (Pubmed, Medline via Embase, Scopus, LILACS, Web of Science, Cochrane Library), Materials Science and Engineering databases (IEEE Explore, Compendex, Proquest), Material Science and Chemical database (Reaxys) so as Patents databases (Questel-Orbit, Espacenet, Patentscope) were consulted as recently as January 2019 to identify all papers and patents potentially relevant to the review. The reference lists of all eligible studies were hand searched for additional published work. Results: After duplicate selection and extraction procedures, 6 relevant full-text articles from the initial 302 and 45 relevant patents from 497 were selected. A modified Consolidated Standards of Reporting Trials (CONSORT) checklist of 14 items for reporting pre-clinical in-vitro studies was used to rate the methodological quality of the selected papers. The overall quality was judged low. Conclusions: Despite the great potential and versatility of SMPs, it was not possible to draw evidence-based conclusions supporting their immediate employment in clinical dentistry. This was due to the weak design and a limited number of studies included within this review and reflects the fact that additional research is mandatory to determine whether or not the use of SMPs in dentistry could be effective. Nevertheless, the qualitative analysis of selected papers and patents indicate that SMPs are promising materials in dentistry because of their programmable physical properties. These findings suggest the importance of furtherly pursuing this line of research.
  • 2.6K
  • 28 Oct 2020
Topic Review
Organosilicon
Organosilicon compounds are organometallic compounds containing carbon–silicon bonds. Organosilicon chemistry is the corresponding science of their preparation and properties. Most organosilicon compounds are similar to the ordinary organic compounds, being colourless, flammable, hydrophobic, and stable to air. Silicon carbide is an inorganic compound.
  • 2.6K
  • 04 Nov 2022
Topic Review
Deicing Fluid
Ground deicing of aircraft is commonly performed in both commercial and general aviation. The fluids used in this operation are called deicing or anti-icing fluids. The initials ADF (Aircraft Deicing Fluid), ADAF (Aircraft Deicer and Anti-icer Fluid) or AAF (Aircraft Anti-icing Fluid) are commonly used.
  • 2.6K
  • 28 Sep 2022
Topic Review
Chloramine
Chloramines are derivatives of ammonia by substitution of one, two or three hydrogen atoms with chlorine atoms: monochloramine (chloroamine, NH2Cl), dichloramine (NHCl2), and nitrogen trichloride (NCl3). The term chloramine also refers to a family of organic compounds with the formulas R2NCl and RNCl2 (where R is an organic group). Monochloramine (chloramine) is an inorganic compound with the formula NH2Cl. It is an unstable colorless liquid at its melting point of −66 °C (−87 °F), but it is usually handled as a dilute aqueous solution, in which form it is sometimes used as a disinfectant. Chloramine is too unstable to have its boiling point measured. It is listed as a tumorigen and mutagen. The wholesale cost in the developing world is about 13.80 to 18.41 U.S. dollars per 500 grams.
  • 2.6K
  • 16 Nov 2022
Topic Review
Charlotte's Web (Cannabis)
Charlotte's Web is a high-cannabidiol (CBD), low-tetrahydrocannabinol (THC) Cannabis strain marketed as a dietary supplement under federal law of the United States. It is produced by the Stanley brothers in Colorado. It does not induce the psychoactive "high" typically associated with recreational marijuana strains that are high in THC. In September 2014, the Stanleys announced that they would ensure that the product consistently contained less than 0.3% THC. Charlotte's Web is named after Charlotte Figi, born (2006-10-18) October 18, 2006 (age 16), whose story has led to her being described as "the girl who is changing medical marijuana laws across America." Her parents and physicians say she experienced a reduction of her epileptic seizures brought on by Dravet syndrome after her first dose of medical marijuana at five years of age. Her usage of Charlotte's Web was first featured in the 2013 CNN documentary "Weed". Media coverage increased demand for Charlotte's Web and similar products high in CBD, which has been used to treat epilepsy in toddlers and children. It was originally called "Hippie's Disappointment" as it was a strain that had high CBD and could not induce a "high". While anecdotal reports have sparked interest in treatment with cannabinoids, there is not enough evidence to draw conclusions with certainty about their safety or efficacy. Physicians worry that some parents are willing to try treatments before proper research has been conducted, and that they may be disappointed. They are "alarmed by parallels to past miracle-cure manias later proved false..." and "...wary of the heightened placebo effect in treatments involving children, when reports of progress depend on the view of parents."
  • 2.6K
  • 02 Nov 2022
Topic Review
Fluorescein Derivatives
This entry is dealing with fluorescein and its derivatives and focuses on their uses as pH-sensor in a biological context. It gathers chemical properties of the fluorescein family of compounds combined to biological issues. 
  • 2.6K
  • 17 Dec 2020
Topic Review
Types of Electrochemical Energy Storage Devices
Researchers are increasingly paying attention to sustainable methods for storing energy. Many researchers are now concentrating their efforts on the development and exploration of novel materials for use in energy storage devices due to the limited supply of existing energy sources such as oil, coal, and natural gas, and escalating regional tensions. Because of these issues, sustainable renewable energy sources have been touted as an alternative to nonrenewable fuels. Deployment of renewable energy sources requires efficient and reliable energy storage devices due to their intermittent nature. High-performance electrochemical energy storage technologies with high power and energy densities are heralded to be the next-generation storage devices. Transition metal chalcogenides (TMCs) have sparked interest among electrode materials because of their intriguing electrochemical properties.
  • 2.5K
  • 09 Jun 2022
Topic Review
Ballast Contamination Mechanisms
Ballasted railway tracks constitute the major transportation grids in many countries across the globe; they convey commuters, as well as freight and bulk cargoes, between cities, mines, farmlands, and ports . The railtrack structure can be categorised into two groups: the substructure and the superstructure. The substructure comprises the subgrade, the sub-ballast, and the ballast, while the superstructure encompasses the sleepers (timber or concrete), the fastening mechanism, and the steel rails.
  • 2.5K
  • 14 Jan 2021
  • Page
  • of
  • 44