Recent Trends in Chemical and Material Sciences Vol. 5

A Detailed Review on the Properties and Applications of WO3 Nanostructure-Based Optical and Electronic Devices

Yu Yao, Dandan Sang, Liangrui Zou, Qinglin Wang, Cailong Liu — Fri, 07 Jan 2022 00:00:00 +0000

Tungsten oxide (WO₃) is a wide bandgap semiconductor exhibiting unintentionally doped n-type, excellent electrical conductivity and high electron Hall mobility, and is therefore considered as a candidate material for application in optoelectronics. Reviews on the applications of WO₃ and its derivatives in electrochemistry, photochemistry, hybrid photocatalysts, electrochemical energy storage, and gas sensors have also been appearing recently. In addition, nanostructured transition metal oxides have attracted a lot of attention in the past decade due to their unique chemical, photochromic, and physical properties. And among these transition metal oxides, the applications of WO₃ nanostructure-based optical and electronic devices have gradually attracted extensive research interest due to their unique photoluminescence (PL), electrochromic, and electrical properties. This review focuses on recent advances related to WO₃, starting from fundamental analysis to improve the optoelectronic, electrochromic, and photochromic properties of WO₃ and to develop advanced devices based on tungsten oxide for optical and electronic applications, including photodetectors, light-emitting diodes (LEDs), PL properties, electrical properties, and optical information storage. This review on the prior findings of WO₃-related optical and electrical devices, as well as concluding remarks and forecasts will help researchers to advance the field of optoelectric applications of nanostructured transition metal oxides.

Investigation of Electrical, Acoustical and Optical Properties of Nanopowder Dispersed Cholesteric Liquid Crystal

Santosh Mani, Suren Patwardhan, Samriti Khosla, Pradip Sarawade — Fri, 07 Jan 2022 00:00:00 +0000

The composite materials based on nanopowder dispersed liquid crystals are important both from fundamental research and device applications due to their unique properties such as improvement in various properties like electrical, optical, thermal, energy storage and spontaneous polarization etc. The proper selection of nanoparticle and its size which to be dispersed in particular liquid crystals is very important for a particular application. In the present study, a ferroelectric nanopowder of Barium Titanate (BaTiO₃) was dispersed in cholesteric liquid crystal and the same was confirmed by Fourier Transform Infrared (FTIR) Spectroscopy. The various acoustical properties like ultrasonic velocity, density, Adiabatic Compressibility, Rao Constant, Wada Constant and Acoustic Impedance were investigated by ultrasonic interferometer at room temperature at fixed frequency. The dielectric constant was determined by Precision Impedance Analyzer. In addition to these investigations, particle size and surface area were also measured. Our investigation shows enhanced in dielectric and acoustical properties which may be useful for device applications extensively in microelectronics, low cost- photovoltaic devices, and custom-shaped containers possibly applied as a coating. The sensitivity of Liquid Crystal is enhanced after dispersing ferroelectric nanopowder which increases the performance of the Liquid Crystal.

Effect of the Temperature and the Holding Time on Carburizing Treatment of 18CN4 and 22MC4 Steels

Younès Benarioua — Fri, 07 Jan 2022 00:00:00 +0000

The surface of mechanical parts subjected to sever loads influence to a great extent the resistance to wear and fatigue. In majority of cases, producing of a hard superficial layer on a less tough substrate is conducive to an increased resistance to mechanical wear and fatigue. Hard layer of steel obtained by carburizing which bonded progressively to martensitic area of high hardness and to a core steel of lower hardness and greater toughness is an example of a good solution of the exposed problem. The high hardness of the carburizing layer is due to the increased concentration of carbon atoms located the interstitial sites of austenite before quenching. The lower hardness of the core after quenching is due to the presence of ferrite and pearlite components which appear if the cooling rate after austenitization becomes lower than the critical one. The objective of the present study was to obtain a cemented surface layer on low alloy steel by means of pack carburizing treatment. Different steel grades, austenitization temperatures as well as different soaking times were used as parameters of the solid carburizing treatment. During this treatment, carbon atoms from the cement powder diffuse toward the steels surface and form compounds of iron carbides. The effect of carburizing parameters on the rate transformation, on the thickness and morphology of carburizing layers, on structure and hardness of surface of steels produced by carburizing treatment was investigated by various characterization technic.

Determining the Bulk Growth, Nucleation Kinetics, Optical and Spectral Analysis of Organic Nonlinear Material: 4-Chloroaniline (pCA) Single Crystal

M. Vijayalakshmi, R. Ezhil Vizhi, D. Rajan Babu — Fri, 07 Jan 2022 00:00:00 +0000

Slow cooling was used to form a single crystal of the organic nonlinear optical substance 4-chloroaniline (pCA). Gravimetric analysis was used to assess the material solubility and the metastable zonewidth MSZW was measured at various temperatures. The values of the induction period were calculated for various supersaturation ratios and temperatures. Experimentally obtained induction period values were used to calculate the interfacial energy. Theoretically, the energy results were compared to experimental values determined from the solubility data. The nucleation parameters were determined including Gibb's free energy change, critical nuclei radius, number of molecules present in the nuclei and nucleation rate. X-ray diffraction analysis was used to estimate the unit cell characteristics. The UV-Vis-NIR spectrum was used to examine the transmission properties of the pCA crystal. FT-Raman spectrum analysis was used to identify the various vibrational modes of different functional groups and assign wavenumbers to them. The nonlinear optical property of the grown crystal was measured using a Q-Switched Nd: YAG laser and the efficiency was evaluated by comparing to that of standard KDP.

Study on Decomposition and Transformation of Calcite-1 by Shearing at High Pressure

Hiroshi Furuichi — Fri, 07 Jan 2022 00:00:00 +0000

Transmission X-ray diffraction patterns were taken on imaging plates from calcite-1 slowly sheared at high pressure up to 16 GPa parallel to (101) plane and in the [2-1-1] direction at room temperature. They showed 22 broad diffused rings. Judging from the appearance of the rings, we may say that the formed substances are in an amorphous state. The patterns revealed that most of the rings do not correspond to calcite-1, but to high-pressure substances except graphite2H, CaO and CaC₂. They were thought to have formed through decomposition and transformation to its polymorphism. They remain at atmospheric pressure. Although the results mentioned above seem to be contrary to the common knowledge among scientists, phenomena that support the results are mentioned in the text. Severe discontinuous dry rubbing decomposes a compound to simple substances and compounds constituting of the elements of the original compound. Calcite-I sheared at high pressure not only transformed to its polymorphism but also decomposed to compounds and simple substances.

An Ecological Approach for Recovery Residual Area of the Human Productive Activity: A Brief Study

Teodoro Semeraro — Fri, 07 Jan 2022 00:00:00 +0000

The growth of urban populations causes cities, and their suburbs, to spread, expand, and replace natural lands by agricultural. Urbanization brings land-use change, altering the relationship between human societies and environmental resources. Therefore, the management of natural resources connected to urban expansion has become one of the most important challenges in attaining sustainable landscape. Quarrying is a crucial component of local socio- economic development providing key materials for infrastructures and buildings. However, like many other human activities, quarrying causes a significant impact on the environment. In Mediterranean countries, quarrying activities exert increasing pressures on limited soil and water resources, thus accelerating erosion processes and subsequent destruction of existing arable lands. Quarrying operations can profoundly alter pre-existing ecosystems and perturb hydro- geological and hydrological regimes. They can profoundly modify the substratum, change landscape patterns and integrity, destroy natural habitats and interrupt their natural succession, as well as alter genetic resources. The resulting situation is seriously compromised by anthropic regeneration processes on degraded sites after the end of quarrying activities, which are not focused on potential natural vegetation which these sites could develop, considering the surrounding ecosystems. The aim of the study is to present an ecological approach to transform the residual area of industrial production into a new ecological patch of the landscape that can support the ecological network. This project aims to integrate environmental and landscape aspects with the economic and social ones in order to guarantee the sustainability of the proposed intervention. The new project modifies the one presented at the start of the quarrying activity which planned planting of trees directly on the bottom of the quarry,. The new project foresees the partial filling of the quarry using waste materials according to the environmental legislation. This allows to protect the groundwater better and to create a microclimate more suited to the development of natural vegetation. The quarry filling activity represents an economic activity for the company and therefore can guarantee the development of jobs for at least 5 years. In addition, the proposed project aims to reconstitute the pre-existing vegetation, consistently with the surrounding ecosystem. This will allow the development of the priority habitat *6220: Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea (Directive 92/43/CEE), producing a landscape of recognized ecological value, not detached from the surrounding landscape. In this way, the closed quarry can act as a stepping-stone and play a significant role in regulating green infrastructure in landscapes. The configuration of the vegetation planed might as well be compatible with the presence of low-density PV panels combining the energy police with Biodiversity Strategy 2030.

Selected Coating Properties of Black Alder Wood as a Function of Surface Preparation, Varnish Type, Coating System and Exposure Conditions

Emilia-Adela Salca — Fri, 07 Jan 2022 00:00:00 +0000

Solid wood furniture still keeps its popularity on the market. Attributes such as reliability, environment-friendliness, appearance, and value are the main parameters to describe the overall quality of solid wood. Light-coloured species are preferred and black alder is one of them. Due to its workability, properties, and excellent grain orientation, black alder has the potential for furniture manufacturing. In this chapter selected coating properties of black alder as a function of surface preparation, varnish type, coating system and various exposure conditions are presented. The findings of various previous studies presented in this work could have practical applications in the furniture industry for producing value-added furniture units according to their specific conditions.

Overview on Organic and Inorganic Materials Used for Furniture and Its Decorations

Emilia-Adela Salca — Fri, 07 Jan 2022 00:00:00 +0000

Natural materials contributed to the development of human life on Earth. These materials have been used for more than 10,000 years. Raw wood or stone have been used for specific purposes and functions, including furniture. Over the centuries the human creativity led to the creation of different types of furniture and decorations. This chapter represents a synthesis of various organic and inorganic materials used for art furniture decorations. Synthetic classifications of the basic materials, as well as specific materials for furniture are compiled. Out of their large variety, selected natural materials are here approached, such as wood, gold, silver, tin, brass, amber, ivory, tortoiseshell and nacre. A specific format is applied to each one of the materials providing information about the structure, classification, identification, properties, and substitutes.