You're using an outdated browser. Please upgrade to a modern browser for the best experience.
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 by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Resistive Gas Sensor
With a series of widespread applications, resistive gas sensors are considered to be promising candidates for gas detection, benefiting from their small size, ease-of-fabrication, low power consumption and outstanding maintenance properties. One-dimensional (1-D) nanomaterials, which have large specific surface areas, abundant exposed active sites and high length-to-diameter ratios, enable fast charge transfers and gas-sensitive reactions. They can also significantly enhance the sensitivity and response speed of resistive gas sensors.
  • 4.8K
  • 17 Aug 2021
Topic Review
Citrus Waste
The scientific name of citrus is Citrus L. and it belongs to the Rutaceae family. It is one of the most important fruit crops that is grown throughout the world. During processing, a large amount of waste is produced from citrus fruits in the form of peel, seeds, and pomace. Every year, the citrus processing industry creates a large amount of waste. The citrus waste is composed of highly bioactive substances and phytochemicals, including essential oils (EOs), ascorbic acid, sugars, carotenoids, flavonoids, dietary fiber, polyphenols, and a range of trace elements.
  • 4.6K
  • 22 Feb 2023
Topic Review
Advantages and Disadvantages of Fenton Process
The Fenton reaction is primarily based on the idea of the formation of oxidizing radicals, which are created by the catalytic action of Fe2+ on the decomposition of H2O2, added in a certain amount and ratio to water, which also contains various organic substances. Oxidative radicals oxidize the present organic substances to varying degrees during the momentary period of their existence. This Fenton reaction is homogeneous because the catalyst (Fe2+ ion) is dissolved in water. However, the catalyst can also be heterogeneous. 
  • 4.4K
  • 22 Feb 2023
Topic Review
Spirulina for Skin Care
Spirulina stands out as a sustainable bioactive microalga with health-promoting properties, and an important active ingredient of natural cosmetics products. 
  • 4.4K
  • 05 Feb 2021
Topic Review
Epoxides Cycloaddition for CO2 Utilization
In the present review (10.3390/pr8050548), CO2 cycloaddition can be seen as a reasonably competent alternative to CO2 transformation, offsetting the high value-added nature by extending material use defer CO2 back to the atmosphere when compared to commodities and fuels such as urea, methanol, and methane.
  • 4.4K
  • 27 Aug 2020
Topic Review
Lipids in Food Flavor Generation
Lipids in food are a source of essential fatty acids and also play a crucial role in flavor and off-flavor development. Lipids contribute to food flavor generation due to their degradation to volatile compounds during food processing, heating/cooking, and storage and/or interactions with other constituents developed from the Maillard reaction and Strecker degradation, among others. The degradation of lipids mainly occurs via autoxidation, photooxidation, and enzymatic oxidation, which produce a myriad of volatile compounds. The oxidation of unsaturated fatty acids generates hydroperoxides that then further break down to odor-active volatile secondary lipid oxidation products including aldehydes, alcohols, and ketones.
  • 4.3K
  • 15 Aug 2022
Topic Review
Catalysts for Synthesis of Ethylene-Propylene-Diene Rubbers
Ethylene-propylene-diene rubbers (EPDM) are one of the most important polyolefin materials widely commercialized and used in various industries in recent years. The production of EPDM is based solely on catalytic coordination polymerization processes. The development of new catalysts and processes for the synthesis of EPDM has expanded the range of products and their manufacturing in terms of energy efficiency, processability, and environmental safety.
  • 4.3K
  • 13 Sep 2022
Topic Review
Applications of Liquid Crystals-Based Sensors
Liquid crystals are a class of chemical substances that exist in intermediate states between crystalline solids and liquids. They thus share the anisotropic properties of crystalline solids as well as fluid properties of isotropic liquids. 
  • 4.2K
  • 23 Mar 2022
Topic Review
Compositional Engineering of Perovskites
We give a systematic overview of compositional engineering by distinguishing the different defect-reducing mechanisms. Doping effects are divided into influences on: (1) crystallization; (2) lattice properties. Incorporation of dopant influences the lattice properties by: (a) lattice strain relaxation; (b) chemical bonding enhancement; (c) band gap tuning. The intrinsic lattice strain in undoped perovskite was shown to induce vacancy formation. The incorporation of smaller ions, such as Cl, F and Cd, increases the energy for vacancy formation. Zn doping is reported to induce strain relaxation but also to enhance the chemical bonding. The combination of computational studies using (DFT) calculations quantifying and qualifying the defect-reducing propensities of different dopants with experimental studies is essential for a deeper understanding and unraveling insights, such as the dynamics of iodine vacancies and the photochemistry of the iodine interstitials, and can eventually lead to a more rational approach in the search for optimal photovoltaic materials.
  • 4.1K
  • 28 Oct 2020
Topic Review
High Performance Liquid Chromatography with Fluorescence Detection Methods
Steroids are compounds widely available in nature and synthesized for therapeutic and medical purposes. Although several analytical techniques are available for the quantification of steroids, their analysis is challenging due to their low levels and complex matrices of the samples. The efficiency and quick separation of the high performance liquid chromatography (HPLC) combined with the sensitivity, selectivity, simplicity, and cost-efficiency of fluorescence, make HPLC coupled to fluorescence detection (HPLC-FLD) an ideal tool for routine measurement and detection of steroids.
  • 4.0K
  • 01 Aug 2022
Topic Review
Imidazoline Surfactants
Imidazoline surfactants are a class of surfactants with a hydrophobic tail and an imidazoline hydrophilic head. They are commonly used as emulsifiers, wetting agents, and cleaning agents in a variety of applications, including personal care, industrial cleaning, and agriculture. Imidazoline surfactants are known for their stability in acidic and alkaline conditions, making them a popular choice for many industrial processes. Imidazoline surfactants are mainly the cationic surfactants that contain an imidazoline ring in their chemical structure. They are commonly used as emulsifiers, corrosion inhibitors, and wetting agents in a variety of industrial and household applications. Imidazoline surfactants are typically synthesized by reacting a fatty acid or fatty amine with an imidazole or imidazoline compound. The resulting surfactants have a unique combination of properties, including excellent emulsification, wetting, and corrosion inhibition abilities.
  • 4.0K
  • 24 Mar 2023
Topic Review
Visible-Light-Promoted Carbonylation Reactions
The abundant and inexpensive carbon monoxide (CO) is widely exploited as a C1 source for the synthesis of both fine and bulk chemicals. In this context, photochemical carbonylation reactions have emerged as a powerful tool for the sustainable synthesis of carbonyl-containing compounds (esters, amides, ketones, etc.).
  • 3.8K
  • 11 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.
  • 3.8K
  • 26 May 2021
Topic Review
Propylene Synthesis
Propylene is one of the most important feedstocks in the chemical industry, as it is used in the production of widely diffused materials such as polypropylene. Conventionally, propylene is obtained by cracking petroleum-derived naphtha and is a by-product of ethylene production. To ensure adequate propylene production, an alternative is needed, and propane dehydrogenation is considered the most interesting process.
  • 3.6K
  • 25 Oct 2021
Topic Review
Direct Synthesis of Silicon Compounds
The development of industrial organosilicon chemistry, and thus the development of silicon chemistry, is partly related to the discovery of the direct process of organosilanes synthesis in the 1940s, which allowed the production of organosilanes and silicone polymers on a large scale, and resulted in the development of new technologies to produce organosilicon monomers and polymers. The direct synthesis process, also known as the Müller–Rochow process, is one of the best-known industrial processes for obtaining organosilicon compounds, and has been the basis of the silicone industry.
  • 3.6K
  • 08 Mar 2023
Topic Review
Gold and Silver Nanoparticle-Based Colorimetric Sensors
Gold and Silver nanoparticles (AuNPs and AgNPs) are perfect platforms for developing sensing colorimetric devices thanks to their high surface to volume ratio and distinctive optical properties, particularly sensitive to changes in the surrounding environment. These characteristics ensure high sensitivity in colorimetric devices. Au and Ag nanoparticles can be capped with suitable molecules that can act as specific analyte receptors, so highly selective sensors can be obtained.
  • 3.5K
  • 23 Nov 2021
Topic Review
Polymers Modifications through Ultraviolet Absorbers Addition
The photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of safe, plastic, ultraviolet stabilizers that do not pose a danger to the environment if released. Plastic ultraviolet photostabilizers act as efficient light screeners (absorbers or pigments), excited-state deactivators (quenchers), hydroperoxide decomposers, and radical scavengers. Ultraviolet absorbers are cheap to produce, can be used in low concentrations, mix well with polymers to produce a homogenous matrix, and do not alter the color of polymers.
  • 3.5K
  • 10 Jan 2022
Topic Review
Biofilm and Pathogen Inhibition in Cooling Towers Using Natural Chemistry
Industrial comfort cooling and process cooling typically employ water evaporative cooling towers (CTs) to dissipate reject heat.  This warm water, enriched with nutrient materials scrubbed from the air or in source water, provides a nurturing environment for a wide variety of neutrophilic microorganisms, some of which are human pathogens.  For example, cases of Legionella pneumophila infection have been traced to CT Systems that have become pubic hazards in recent years.  Typically, one or more toxic microbicides are applied to control the problem.  This article highlights two case studies that utilize ultra-softened (<0.3 mg/L total hardness), highly-concentrated chemical components, naturally present in almost all makeup water sources used by CT Systems, that can generate high-pH, high-TDS cooling water.  At sufficient concentrations, these two natural parameters are hostile to microorganisms, including protozoa and slime-forming (biofilm) bacteria that harbor pathogens.  Field testing for Adenosine Tri-Phosphate (ATP), reported in Relative Light Units (RLU), provides a quick, sensitive method to detect all water-borne microbiological activity present in CT Systems and verifies the effectiveness of the anti-microbial program by quantifiable data, reported as ATP-RLU.
  • 3.5K
  • 28 Oct 2020
Topic Review
β-Ionone
β-Ionone is a natural plant volatile compound, and it is the 9,10 and 9′,10′ cleavage product of β-carotene by the carotenoid cleavage dioxygenase. β-Ionone is widely distributed in flowers, fruits, and vegetables. β-Ionone and other apocarotenoids comprise flavors, aromas, pigments, growth regulators, and defense compounds; serve as ecological cues; have roles as insect attractants or repellants, and have antibacterial and fungicidal properties. In recent years, β-ionone has also received increased attention from the biomedical community for its potential as an anticancer treatment and for other human health benefits. However, β-ionone is typically produced at relatively low levels in plants. Thus, expressing plant biosynthetic pathway genes in microbial hosts and engineering the metabolic pathway/host to increase metabolite production is an appealing alternative.
  • 3.5K
  • 26 Apr 2021
Topic Review
Organic Binders in Archaeological Wall Paintings
Binding media are complex materials, employed to allow pigment grains to adhere to each other and to the surface of the support, through the formation of a coherent and homogeneous film. The function of the binder consists, therefore, in keeping the pigment particles firmly together and at the same time adhering them in the form of a coherent thin film to the surface of the support. The binder must obviously be in the fluid state, in order to form with the pigments a stable, homogeneous, stretchy, and viscous dough.   For the realization of wall paintings and, in later times, for their preservation, different materials with functions of binders, adhesives, paints, protective and consolidating were and are still necessary. There is a very large class of products which can have both constitutive functions but also a function of conservation and restoration. 
  • 3.5K
  • 21 Oct 2021
  • Page
  • of
  • 15
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of COVID-19
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Academic Video Service
Feedback