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:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Sensors for Hydrogen Peroxide Detection
 Hydrogen peroxide (H2O2) is a key molecule in numerous physiological, industrial, and environmental processes. H2O2 is monitored using various methods like colorimetry, luminescence, fluorescence, and electrochemical methods. Here, we aim to provide a comprehensive review of solid state sensors to monitor H2O2. The review covers three categories of sensors: chemiresistive, conductometric, and field effect transistors. A brief description of the sensing mechanisms of these sensors has been provided. All three sensor types are evaluated based on the sensing parameters like sensitivity, limit of detection, measuring range and response time. We highlight those sensors which have advanced the field by using innovative materials or sensor fabrication techniques. Finally, we discuss the limitations of current solid state sensors and the future directions for research and development in this exciting area. 
  • 2.4K
  • 30 Jan 2021
Topic Review
Cotton Production in Pakistan
Cotton production in Pakistan is integral to the economic development of the country. The nation is largely dependent on the cotton industry and its related textile sector, and the crop has been given a principal status in the country. Cotton is grown as an industrial crop in 15% of the nation's land during the monsoon months of May to August, known as the kharif period, and is grown at a smaller scale between February and April. Record production of cotton was reported at 15 million bales of 470 pounds (210 kg) each in the form of phutti (seed cotton) during 2014–15, which was an 11% rise compared to the previous season (2013–14). Production-wise, as of 2012–13, Pakistan occupied the fourth position among the cotton growers of the world, the first three being China, India and the United States, in that order. In respect of exports of raw cotton, Pakistan holds third position, and is the fourth in consumption (about 30 and 40 per cent of its production). It is the largest exporter of cotton yarn.
  • 2.4K
  • 16 Nov 2022
Topic Review
Resistance of PVD Coatings
Due to the increasing maintenance costs of hydraulic machines related to the damages caused by cavitation erosion and/or erosion of solid particles, as well as in tribological connections, surface protection of these components is very important. Up to now, numerous investigations of resistance of coatings, mainly nitride coatings, such as CrN, TiN, TiCN, (Ti,Cr)N coatings and multilayer TiN/Ti, ZrN/CrN and TN/(Ti,Al)N coatings, produced by physical vapor deposition (PVD) method using different techniques of deposition, such as magnetron sputtering, arc evaporation or ion plating, to cavitation erosion, solid particle erosion and wear have been made. The results of these investigations, degradation processes and main test devices used are presented in this paper. An effect of deposition of mono- and multi-layer PVD coatings on duration of incubation period, cumulative weight loss and erosion rate, as well as on wear rate and coefficient of friction in tribological tests is discussed. It is shown that PVD coating does not always provide extended incubation time and/or improved resistance to mentioned types of damage. The influence of structure, hardness, residence to plastic deformation and stresses in the coatings on erosion and wear resistance is discussed. In the case of cavitation erosion and solid particle erosion, a limit value of the ratio of hardness (H) to Young’s modulus (E) exists at which the best resistance is gained. In the case of tribological tests, the higher the H/E ratio and the lower the coefficient of friction, the lower the wear rate, but there are also many exceptions
  • 2.4K
  • 13 Oct 2020
Topic Review
Biological Degradation of Polymers
Biodegradable plastics can make an important contribution to the struggle against increasing environmental pollution through plastics. This entry provides an overview of the main environmental conditions in which biodegradation takes place and then presents the degradability of numerous polymers. 
  • 2.4K
  • 23 Nov 2020
Topic Review
Electrode Passivation
The main reason for electrode passivation is adsorption/deposition of a passivating compound on working electrode surface. The most pronounced consequences are the decrease of the rate of electrode reaction resulting in the shift of half-wave or peak potential to more negative (in the case of cathodic reaction) or to more positive (in the case of anodic reaction) potentials and in the decrease of peak current, which is especially in the case of pulsed technique influenced by this rate. 
  • 2.4K
  • 22 Feb 2021
Topic Review
Applications of Coacervates
Coacervates are one of the most intriguing systems in colloid chemistry. The term comes from the Latin words “co” (jointly) and “acerv” (a mound). Coacervation is a phenomenon in which a colloidal solution gets separated into colloid-rich and colloid-poor phases.
  • 2.4K
  • 15 Sep 2022
Topic Review
Removal of Purines from Beer
Beer corresponds to a fermented alcoholic beverage composed of several components, including purine compounds. These molecules, when ingested by humans, can be catabolized into uric acid, contributing to uric acid’s level increase in serum, which may lead to hyperuricemia and gout. To assure a proper management of this disease, physicians recommend restrictive dietary measures, particularly by avoiding the consumption of beer. Therefore, it is of relevance to develop efficient methods to remove purine compounds from alcoholic beverages such as beer. There are several enzymatic, biological, and adsorption methods reported envisaging purine compounds’ removal. Some enzymatic and biological methods present drawbacks, which can be overcome by adsorption methods. Within adsorption methods, adsorbent materials, such as activated carbon or charcoal, have been reported and applied to beer or wort samples, showing an excellent capacity for adsorbing and removing purine compounds. By ensuring the selective removal of purine compounds from this beverage, beer can be taken by hyperuricemic and gouty patients, avoiding restrictive dietary measures, while decreasing the related healthcare economic burden. 
  • 2.3K
  • 23 Nov 2021
Topic Review
Basalt Fiber-reinforced Polymer Properties
Reducing the fingerprint of infrastructure has become and is likely to continue to be at the forefront of stakeholders’ interests, including engineers and researchers. It necessary that future buildings produce minimal environmental impact during construction and remain durable for as long as practicably possible
  • 2.3K
  • 08 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.
  • 2.3K
  • 25 Oct 2021
Topic Review
Chitin
       Chitin, being the second most abundant biopolymer after next to cellulose, has been gaining popularity since its initial first discovery by Braconot in 1811. However, fundamental knowledge and literature on about chitin and its derivatives from insects are difficult to obtain. The most common and sought-after sources of chitin are shellfishes (especially crustaceans) and other aquatic invertebrates. The amount of shellfishes available is obviously restricted by the amount of food waste that is allowed; hence, it is a limited resource. Therefore,Hence, insects are the best choices since, out of 1.3 million species in the world, 900,000 are insects, making them the most abundant species in the world. In this review, a total of 82 samples from shellfishes—crustaceans and mollusks (n = 46), insects (n = 23), and others (n = 13)—have been collected and studied for their chemical extraction of chitin and its derivatives. The aim of this paper is to review the extraction method of chitin and chitosan for a comparison of the optimal demineralization and deproteinization processes with, so as to consideration of insects as alternative sources of chitin. The methods employed in this review are based on comprehensive bibliographic research. Based on previous data, chitin and chitosan yield contents of insects in their study favorably compares and competes with those of commercial chitin and chitosan—for example, 45% in Bombyx eri, 36.6% in Periostracum cicadae (cicada sloughs), and 26.2% in Chyrysomya megacephala. Therefore, according to the data reported by previous researchers, with comparable yield values to those of against crustacean chitin and the great interests of in insects as alternative sources, efforts towards comprehensive knowledge in this field are relevant.
  • 2.3K
  • 30 Oct 2020
  • Page
  • of
  • 467
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
Video Production Service
Feedback