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
Advances in Printed Circuit Board Recycling
Toward improved printed circuit board recycling, recent development and research favours a strategy based on first dismantling WPCBs followed by efficiently sorting electronic components (ECs). This allows obtaining various fractions: (i) bare boards; (ii) solder; (iii) ECs sorted in elementally enriched subfractions. The goal is for each fraction, or subfraction, to have the simplest elemental composition possible, making them easier to reuse directly or recycle, and making it now possible to recover valuable metalssuch as Ti, GaBa, Ta, Nb, W, Lanthanides.
  • 682
  • 19 Apr 2022
Topic Review
High-Temperature Polymer Electrolyte Membranes
Sufficient access to clean energy sources is one of the ongoing key challenges for global development that directly impacts industrial development, economic growth, and human well-being. Historically, the energy sector is widely dominated based on fossil fuels (such as petroleum fuels, natural gas, coal, etc.), which are the primary sources of carbon dioxide (CO2) and other greenhouse gases emissions in the environment. 
  • 674
  • 09 Sep 2021
Topic Review
Synthesis of TiO2 at the Industrial Level
Among a diverse range of dense mineral reserves found across the world, only ilmenite and rutile ores are capable of yielding titanium compounds, specifically titanium dioxide, through industrial processes. Although ilmenite and rutile are extensively used to extract TiO2 at the industrial level, through the sulphate and chloride processes, they can also be recognized to possess the potential to be employed as the raw material to synthesize other titanium compounds as well. Since titanium containing compounds possess the capability to be applied in numerous applications, such as environmental remediation, energy technologies, the pharmaceutical industry, paint industry and textile industry, exploration of the ability of these ore materials to yield titanium species is highly significant in the field of research as well as the industrial sector.
  • 672
  • 17 May 2023
Topic Review
Heterogeneous Catalysis for Biomass Valorization and Fine-Chemicals Production
Heterogeneous catalysts are progressively expanding their field of application, from high-throughput reactions for traditional industrial chemistry with production volumes reaching millions of tons per year, a sector in which they are key players, to more niche applications for the production of fine chemicals. These novel applications require a progressive utilization reduction of fossil feedstocks, in favor of renewable ones. Biomasses are the most accessible source of organic precursors, having as advantage their low cost and even distribution across the globe. Unfortunately, they are intrinsically inhomogeneous in nature and their efficient exploitation requires novel catalysts.
  • 667
  • 17 Dec 2021
Topic Review
Photocatalytic Desulfurization
Desulfurization of fuels such as diesel, gasoline, kerosene, and jet fuel has been a challenging operation and remains critical to the petrochemical industry. The main naturally occurring sulfur-containing organic compounds (SCCs) are sulfides, disulfides, mercaptans, thiophene (Th) and its derivatives (benzothiophene (BT), dibenzothiophenes (DBTs), 4-methylbenzothiophene (4-MBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), 3,7-dimethyldibenzothiophene (3,7-DMDBT), and 2,8-dimethyldibenzothiophene (2,8-DMDBT)). The presence of these SCCs in fuels is undesirable since they create problems during refining, namely deactivation of some catalysts and corrosion of equipment. Moreover, sulfur compounds release toxic SOx and cause severe environmental problems: water and air pollution, global warming, ecological instability, as well as the harmful impact on living organisms. Many countries (USA, European Union, Japan, China and so on) have introduced strict standards to limit the content of sulfur in fuels to 10 ppm.
  • 665
  • 23 Sep 2022
Topic Review
Nanoscience Delivery Systems Used in Nutricosmetic Sector
Nutricosmetics is a new cosmetics sector that uses an integrated “In and Out” approach. Cosmetic products together with food supplements such as micronutrients (minerals, vitamins), macronutrients (peptides, essential fatty acids), and botanicals (herbal and fruit extracts)  are employed to nourish the skin and reduce skin aging.  Biopolymeric nanoparticles, nanofibers, nanoemulsions, nanocapsules, and colloids are delivery systems applied to improve the bioactive components’ performance in food supplements and cosmetics. The toxicity of nano-sized delivery systems is unclear despite food supplements and cosmetic industries using them. 
  • 664
  • 23 Mar 2022
Topic Review
Cu-Based Catalytic Sites for Methane to Methanol
Direct conversion of methane to methanol is an effective and practical process to improve the efficiency of natural gas utilization. Copper (Cu)-based catalysts have attracted great research attention, due to their unique ability to selectively catalyze the partial oxidation of methane to methanol at relatively low temperatures. Many different catalysts have been studied to achieve a high conversion of methane to methanol, including the Cu-based enzymes, Cu-zeolites, Cu-MOFs (metal-organic frameworks) and Cu-oxides.
  • 661
  • 08 Nov 2022
Topic Review
Molecular Solar Thermal Energy Storage
The design of molecular solar fuels is challenging because of the long list of requirements these molecules have to fulfil: storage density, solar harvesting capacity, robustness, and heat release ability. All of these features cause a paradoxical design due to the conflicting effects found when trying to improve any of these properties.
  • 658
  • 06 Sep 2022
Topic Review
PENG-Based Non-Invasive Medical Sensors
Piezoelectric nanogenerators (PENGs) not only are able to harvest mechanical energy from the ambient environment or body and convert mechanical signals into electricity but can also inform people about pathophysiological changes and communicate this information using electrical signals, thus acting as medical sensors to provide personalized medical solutions to patients.
  • 654
  • 19 Jan 2023
Topic Review
Photocatalytic Methane Reforming
Methane reforming is an important potential technology for solving both environmental and energy problems. This technology is important because methane is counted as a greenhouse gas, but on the other hand, it can be reformed into industrially valuable compounds.
  • 651
  • 15 Jan 2021
Topic Review
Three Species of Lycium Genus
The genus Lycium belongs to the Solanaceae family and comprises more than 90 species distributed on diverse continents. Lycium barbarum is by far the most studied and considered to possess healthy properties. The biological properties of L. barbarum fruits are mainly attributed to polysaccharides, particularly complex glycoproteins with different compositions. In contrast, L. europaeum, L. intricatum, and L. schweinfurthii found particularly in the Mediterranean region, are poorly studied, although used by native populations. The evaluation of the chemical composition and biological, nutritional, or pharmacological properties of these species must be unveiled. Such studies will not only enrich knowledge but may also lead to the use of some of these species in food to replace L. barbarum or other plant species. Since L. europaeum, L. intricatum, L. infaustum and L. schweinfurthii generally occur in impoverished areas, the culture and transformation of these species products could contribute to the sustained enrichment of the populations living in those zones.
  • 649
  • 17 Jan 2023
Topic Review
Bioactive Compounds from Fruit Crop Wastes
The food industry as a whole is one of the main contributors for food losses and waste generation. To deal with such wastes, research and efforts have been made for the development and valorization of bioactive compounds present in food wastes such as leaves, peels, seeds, and pulp.
  • 648
  • 10 Feb 2023
Biography
Alexander Gaskov
Professor Alexander Gaskov, our dear colleague, friend and teacher, passed away on 18 January 2021, from COVID-19. He was a brilliant scientist in the area of chemistry of semiconductor materials for physical and chemical sensors. He spent his entire research career, which began in 1966, in the Division of Inorganic Chemistry of the Department of Chemistry, Moscow State University. During all hi
  • 642
  • 31 Aug 2022
Topic Review
Triboelectric Nanogenerators in Sustainable Chemical Sensors
The rapid development of sensing technology has created an urgent need for chemical sensor systems that can be rationally integrated into efficient, sustainable, and wearable electronic systems. In this case, the triboelectric nanogenerator (TENG) is expected to be a major impetus to such innovation because it can not only power the sensor by scavenging mechanical energies and transforming them into electricity but also act as the chemical sensor itself due to its intrinsic sensitivity towards the chemical reaction that occurs at the triboelectric interface.
  • 639
  • 24 Nov 2022
Topic Review
Nonprecious Metal Homogeneously Catalyzed Formic Acid Dehydrogenation
Formic acid (FA) possesses a high volumetric concentration of H2 (53 g L−1). Moreover, it can be easily prepared, stored, and transported. Therefore, FA stands out as a potential liquid organic hydrogen carrier (LOHC), which allows storage and transportation of hydrogen in a safe way. The dehydrogenation to produce H2 and CO2 competes with its dehydration to give CO and H2O. For this reason, research on selective catalytic FA dehydrogenation has gained attention in recent years. Several examples of highly active homogenous catalysts based on precious metals effective for the selective dehydrogenation of FA have been reported. Among them are the binuclear iridium-bipyridine catalysts described by Fujita and Himeda et al. (TOF = 228,000 h−1) and the cationic species [IrClCp*(2,2′-bi-2-imidazoline)]Cl (TOF = 487,500 h−1). However, examples of catalytic systems effective for the solventless dehydrogenation of FA, which is of great interest since it allows to reduce the reaction volume and avoids the use of organic solvents that could damage the fuel cell, are scarce. 
  • 636
  • 30 Nov 2021
Topic Review
Basic Principles of COF-Based Sensing
Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers with polygonal porosity and highly ordered structures. The most prominent feature of the COFs is their excellent crystallinity and highly ordered modifiable one-dimensional pores. Since the first report of them in 2005, COFs with various structures were successfully synthesized and their applications in a wide range of fields including gas storage, pollution removal, catalysis, and optoelectronics explored. In the meantime, COFs also exhibited good performance in chemical and biological sensing, because their highly ordered modifiable pores allowed the selective adsorption of the analytes, and the interaction between the analytes and the COFs’ skeletons may lead to a detectable change in the optical or electrical properties of the COFs.
  • 632
  • 17 May 2022
Topic Review
Enzymes Related to Early Skin-Aging
Skin is the largest organ of the human body and is a great shield, as it protects it from external infections (environmental and chemical pollutants) as well as from UV irradiation. However, it is vulnerable since its degradation can occur both due to extrinsic and intrinsic factors, leading to early aging. Among all, extrinsic skin aging, called photoaging, is a remarkable result of oxidative stress caused by UV irradiation. In addition, reactive oxygen species (ROS) have also been found to contribute to skin aging, as they are produced in skin cells through UV irradiation, although at low concentrations they could be beneficial for some signaling pathways. Environmental and chemical pollutants also produce ROS, triggering a number of pathologies. Skin’s connective tissue includes a number of constituents, including collagen fibrils, elastic fibers, glycoproteins, and glycosaminoglycans. Among all, proteins like elastin, collagen, the glycosaminoglycan hyaluronic acid, and a polymeric pigment called melanin play pivotal roles in the regulation of skin’s elasticity as well as its protection against UV irradiation.
  • 632
  • 28 Nov 2022
Topic Review
Vanadium Oxides
Vanadium-based compounds exhibit a range of oxidation states, including V5+, V4+, V3+, and V2+, making them feasible to composite with many other anions and cations to form vanadium oxides, vanadium carbides, vanadium nitrides, vanadium sulphides, vanadium phosphates, and metal vanadates.Among them, vanadium oxides have attracted interest for energy storage in the past decades.
  • 630
  • 24 May 2021
Topic Review
Hydrogen Production via Chemical Looping Water-Splitting
Hydrogen is an important green energy source and chemical raw material for various industrial processes. The major technique of hydrogen production is steam methane reforming (SMR), which suffers from high energy penalties and enormous CO2 emissions. As an alternative, chemical looping water-splitting (CLWS) technology represents an energy-efficient and environmentally friendly method for hydrogen production. The key to CLWS lies in the selection of suitable oxygen carriers (OCs) that hold outstanding sintering resistance, structural reversibility, and capability to release lattice oxygen and deoxygenate the steam for hydrogen generation. 
  • 627
  • 26 Apr 2023
Topic Review
Biolubricants Based on Vegetable Oils
Biolubricants are a kind of lubricant obtained from plants (mainly vegetable oils such as cardoon, corn, palm, safflower, or rapeseed oils), which makes them biodegradable and environmentally friendly (especially important if they are spilled in the environment).  They mainly act as anti-friction media between contact surfaces.
  • 623
  • 20 Sep 2023
  • Page
  • of
  • 15
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