Review of the Nanostructuring and Doping Strategies for High-Performance ZnO Thermoelectric Materials

Unique properties of thermoelectric materials enable the conversion of waste heat to electrical energies. Among the reported materials, Zinc oxide (ZnO) gained attention due to its superior thermoelectric performance. In this review, we attempt to oversee the approaches to improve the thermoelectric properties of ZnO, where nanostructuring and doping methods will be assessed. The outcomes of the reviewed studies are analysed and benchmarked to obtain a preliminary understanding of the parameters involved in improving the thermoelectric properties of Zn

Research summary on the processing, mechanical and tribological properties of aluminium matrix composites as effected by fly ash reinforcement

Fly ash is the main waste as a result of combustion in coal fired power plants. It represents about 40% of the wastes of coal combustion products (fly ash, boiler ash, flue gas desulphurization gypsum and bottom ash). Currently, coal waste is not fully utilized and waste disposal remains a serious concern despite tremendous global efforts in reducing fossil fuel dependency and shifting to sustainable energy sources. Owing to that, employment of fly ash as reinforcement particles in metallic matrix composites are gaining momentum as part of recycling effort and also as a means to improve the specifications of the materials that are added to it to form composite materials. Many studies have been done on fly ash to study composite materials wear characteristics including the effects of fly ash content, applied load, and sliding velocity. Here, particular attention is given to studies carried out on the influence FA content on physical, mechanical, and the thermal behavior of Aluminium-FA composites. Considerable changes in these properties are seen by fly ash refine-ment with limited size and weight fraction. The advantage of fly ash addition results in low density of composites materials, improvement of strength, and hardness. It further reduces the thermal expansion coefficient and improve wear resistance

Microstructural characterization of fly ash particulate reinforced AA6063 aluminium alloy for aerospace applications

Aluminium-fly ash (FA) particulate reinforced composites (AA6063-FA) have been used in automotive and aerospace industries because of their low density and good mechanical properties. Three different weight fraction of FA: 2%, 4% and 6% are added to AA6063 alloy using compocasting method. The effect of FA particulates on microstructure, density and compression strength of AA6063- FA composites are investigated. Field Emission Scanning Electron Microscope (FESEM) micrographs reveal that the FA particulates are uniformly distributed in AA6063 alloy. The results also show that density, compression strength and microstructure of the AA6063-FA composites are significantly influenced by the FA amount. The increase in the weight fraction of FA will improve the microstructure and enhance the compression strength. The density of AA6063-FA composites decreases as the incorporation of FA increases

Photo-electrochemically synthesized light emtting nanoporous silicon based UV photodetector: influence of current density

Nanoporous silicon (n-PSi) with diverse morphologies was prepared on silicon (Si) substrate via photo-electrochemical etching technique. The role of changing current density (15, 30 and 45 mA cm−2) on the structure, morphology and optical properties was determined. As-prepared samples were systematically characterized using XRD, FESEM, AFM and photoluminescence measurements. Furthermore, the achieved n-PSi sample was used to make metal–semiconductor–metal (MSM) UV photodetector. The performance of these photodetectors was evaluated upon exposing to visible light of wavelength 530 nm (power density 1.55 mW cm−2), which exhibited very high sensitivity of 150.26 with a low dark current. The achieved internal photoconductive gain was 2.50, the photoresponse peak was 1.23 A W−1 and the response time was 0.49 s and the recovery time was 0.47 s. Excellent attributes of the fabricated photodetectors suggest that the present approach may provide a cost effective and simple way to obtain n-PSi suitable for sundry applications

Recent Advances in Porous Ceramics

Porous ceramics have recently gained growing importance in industry because of their many applications like filters, absorbers, dust collectors, thermal insulation, hot gas collectors, dielectric resonators, bioreactors, bone replacement and automobile engine components. Generally, porous ceramics have good properties such as mechanical strength, abrasion resistance, and chemical and thermal stability. These porous network ceramic structures also have relatively low density, low mass and low thermal conductivity. Furthermore, permeability is one of the most important properties of porous ceramics for different applications such as membranes because this property directly relates to the pressure drop during filtration. Pore size control is one key factor in fabrication of porous ceramics. The size of particles and their distribution of the raw materials, manufacturing techniques, types of binder used, distribution of binder, and sintering affect the final porosity and pore connectivity, are important things that must be considered during the manufacturing of a porous ceramic body. Therefore, the development of porous ceramic research requires sufficient mechanical and chemical stability as well as permeability. This book covers a wide range of topics such as porous ceramic structure and properties, preparation, simulation and fabrication, sintering, applications for bioceramics, sensors, magnetics and energy saving

Additive manufacturing: a layered taxonomy and classification for material engineering process

Material engineers continuously make every effort for the evolution of novel and prevailing production performances to supply our biosphere with resource-proficient, economical, and hygienic substances with superior package operation. The mitigation of energy depletion and gas releases as an utmost significance worldwide is a renowned datum; which also needs the improvement of delicate substances employing budget-proficient and ecologically pleasant methods. Consequently, copious exploration has been aimed in the study of methods retaining a potential to wrestle these widespread essentials. Material engineering processes have advanced as a feasible substitute for conventional steel fragment construction methods. CE has experienced an extraordinary advancement throughout the previous three decades. It was originally utilised uniquely as a state-of-the-art reserve of the paradigm. Referable to the expertise development which permits merging countless engineering procedures for the output of a modified portion that employed intricate configurations, CE expertise has got cumulative responsiveness. As such, this article intends to furnish a comprehensive appraisal of chemical fabrication progressions for steel substance evolution utilised in different applications. The inspection encompasses the current advancement of CE know-hows, a detailed taxonomy and classification of manufacturing operations. The focal point of the upcoming perspective of CE in substance investigation and application is further deliberated

A review on graphene - based polymer composite coatings for the corrosion protection of metals

Graphene-based coating is an emerging field that focuses on developing advanced coatings by exploiting new generation materials with superior properties. Researchers are striving to develop coatings that are cost-effective, easy to prepare and highly effective by integrating graphene with a wide range of suitable materials for surface protection applications. In this critical review, different types of high performing graphene-based polymer composite coatings have been described for anticorrosion application. An in-depth survey on methods of preparation, coating application techniques and their influence on the corrosion behavior of coatings is presented briefly. Newly developed strategies to enhance the protection efficiency of graphene-polymer matrix coatings are also covered concisely. The authors hope that this review will assist prospective academicians and researchers in developing novel highly efficient graphene-based anticorrosion composite coatings for industrial applications