Research Aspects in Chemical and Materials Sciences Vol. 6

In order to address the shortcomings of conventional rubber seals, such as high- and low-temperature resistance, easy aging, and inadequate load-bearing performance, O-type metal rubber seals with a large ring-to-diameter ratio were created using the cold stamping method and stainless steel wire as raw material. Heat treatment and porosity were investigated for their effects on the compression and tensile properties of test samples. It was discovered during uniaxial compression testing that the test sample exhibited typical hysteresis properties, and that the loss factor and energy dissipation of the sample with the same size but varied porosity increased with the reduction in porosity. The heat-treated sample's loss factor and energy dissipation were less than those of the untreated sample. As a result, energy dissipation and change of loss factor are both increased with decreasing porosity. Four samples with varying levels of porosity had their yield strength, ultimate tensile strength, and modulus of elasticity evaluated. It was discovered that the three metrics increased as porosity decreased. Additionally, as porosity decreased, the conductivity of the thermal treatment rose. The three aforementioned parameters were all typically raised. This demonstrated that metal rubber materials have good mechanical properties in high-temperature environments, effectively resolving the issue of ordinary rubbers' susceptibility to aging and failure under typical working conditions. This has significant engineering applications in both theory and practice.

A systematic study on the structural, microstructural and optical properties of Cr doped ZnO nanoceramics with different milling time and temperature has been reported. The weight percent of Cr in ZnO varies from 1 to 4% and the milling time varied from 2h to 10h. X-ray diffraction (XRD) data reveals that up to 3% of Cr can be doped in to ZnO after 10 hour of milling showing single phase polycrystalline Cr-doped ZnO, but for x = 0.04 few peaks related to Cr₂O₃ was noticed. But after calcination at 900 \(^{\circ}\)C no additional peak related to Cr₂O₃ was observed for x = 0.04 sample forming single phase. So up to x = 0.04 Cr is below the solubility limit of Cr in ZnO by ball milling. The data is well matched with rietveld refinement of XRD pattern. Particle growth was observed from FESEM micrograph after calcination and sintering. The band gap of 2% of Cr doped ZnO varies from 3.18eV to 3.06eV with milling from 2hr to 10hr again with increasing Cr concentration from x = 0 to x = 0.04 the variation of band gap was from 3.22eV to 3.235eV. Cr doped ZnO shows blue shift with doping concentration and sintering.

This article is a brief summary article. The results of the three times experiments are reviewed. Two heterogeneous catalysis mechanisms are introduced, namely: Chemical Reaction Mode Cyclic Catalysis Mechanism-CRM and Electron Cyclic Donate-Accept Catalysis Mechanism-ECDAM or Electron Orbital Deformation-Recovery Cyclic Catalysis Mechanism-EODRM. Some difficulties encountered by CRM are listed. The author clearly points out that the CRM is not credible. This false theory has misled us for more than 100 years. About ECDAM, the article also gives a brief description. The view point of ECDAM is that the catalysis phenomenon are physical rather than chemical phenomenon. The catalysts do not participate in chemical reactions, It's just contact, electron cyclic donate-accept or electron orbital deformation-recovery cycle. The theory contains three viewpoints:

1. There is a boundary between the catalyst and the poison.
2. The active of the catalyst or the degree of toxicity of the poison is closely related to the electronegative value of the catalyst or poison.
3. The active of catalyst is closely related to the chemical state.

The work reported the rapid synthesis of nano zeolitic imidazolate framework-8 (ZIF-8) crystals at room temperature in the methanol with the support of ultrasound, and the preparation of porous ZnO by calcination of the ZIF-8 material in the air. The photocatalytic activity of the obtained materials was evaluated through the degradation of methylene blue (MB) under UV irradiation. The results indicated that ZIF-8 and the materials obtained by ZIF-8 heat treatment have photocatalytic activity. However, the MB degradation photocatalytic performance of ZnO samples derived from ZIF-8 was still lower than that of the ZIF-8 samples, indicating that ZIF-8 is an effective photocatalyst for organic pollutant degradation.

Plastics is already an integral part of man’s daily lives. Whatever man is doing, wherever man is moving, he will use plastic. Decades of experiences from plastic manufacturers led to the versality, flexibility and applicability in almost every activity man could ever had. But the affordability and availability of plastics lead human to a throw-away culture, that results to severe plastic pollution both in grounds or in waters. In the Philippines alone, 163 million plastic sachet packets, 48 million shopping bags, and 45 million thin film bags are used daily, with approximately 0.28 - 0.75 million tons dropped into the ocean each year. Plastics cannot be totally replaced with other materials. There are products, containers, bottles that can be used as replacement but the superior qualities of plastics make it the first choice of everyone. In well populated cities and countries with lesser natural resources, replacing plastics with organic materials like papers poses worse environmental footprints. As it is seen that plastics are irreplaceable, and to mitigate the problems on plastics, lots of international projects and collaborations that aims to developed technologies and system that will replace fossil-based plastics with biodegradable, recyclable, bio-based plastics and create the circular economy of plastics, aside from the plastic waste management projects such as the 3R’s, the ecoloop, etc.  Prevention is better than cure. While every country implements waste management, there are pilot projects that manufactures bio-based or biodegradable plastics. The main objective is to use biodegradable materials in manufacturing plastic materials making the product biodegradable plastics. The Project ‘PEFerence’ and the ‘Project Effective are two huge international and inter-industry collaborations funded by the European Union to pilot manufacturing bio-based plastics. With the production and process being perfected through times, it is expected that the capability of the projects to manufacture more bio-based plastics and the utilization of such products will eventually increase, and decrease the price.

The improvement of performance and decrease in emissions from a 4-stroke, single-cylinder diesel engine powered by Diesel-Waste Plastic Oil (WPO) obtained through pyrolysis process is discussed here. The Diesel-WPO blend and the nano additive were mixed using an ultrasonicator and a mechanical homogenizer. The Rice husk-based nanoadditives were mixed with WPO at concentrations of 25, 50, 75, and 100 ppm. The fuel mixture's stability was examined before it was employed in a diesel engine for performance and emission research. The results show that when compared to diesel, the W20 combination (20% WPO, 80% Diesel) indicated a 3.5% decrease in brake thermal efficiency (BTE) and an increase in brake-specific fuel consumption (BSFC) of 5.7%, at full load. When compared to Diesel, the W20NA75 blend's BTE increased by 2.6% and its fuel consumption decreased by 3.1% after the addition of Non Metallic Nano Additives (NA). When compared to diesel at maximum load, emissions such as hydrocarbon (HC), carbon monoxide (CO), and smoke opacity decreased by 15.3%, 7%, and 20.4%, respectively, while oxides of nitrogen (NOx) emission increased by 14.1%. It can be concluded that adding rice husk nanoparticles to W20 blend at a 75 ppm concentration helped CI engines run more efficiently and emit less pollutants. The inclusion of non-metallic nanoparticles to the WPO-diesel blend had a significant impact on the results, which also revealed a significant improvement in brake thermal efficiency.

We calculated the structural, electronic and optical properties of the LaxSc1-xSb ternary alloy with 0 \(\le\) x \(\le\) 1 by using the first-principles full potential linear muffin-tin orbital (FPLMTO) method based on the generalized gradient approximation (GGA96). The lattice constants, bulk modulus, electronic band structure, density of states, and optical properties such as dielectric function, refractive index, and extinction coefficient for (x=0.25, 0.5, and 0.75) are calculated and discussed. Our results are in good agreement with available data in the literature. It is observed that for x=0.75, the compound is characterized by the direct band gap materials approximately zero between M and \(\Gamma\) direction. It has been found that the La0.75Sc0.25Sb system is probably a semiconductor despite that both binary (LaSb) and (ScSb) are metals in the rocksalt phase. The density of states calculations indicates that the lower part of the conduction b and is totally occupied by Sc-3d and La-4f states and the upper part of the conduction band is occupied by the La-5d state while the lower part of the valence band is dominated by the Sb-5p state.

This study analyzed the behaviour of organization molecular chemically modified tetraether lipids caldarchaeol-PO₄ on the modification of the solid surface-supported wafer silicon to amino-silanised using Langmuir-Blodgett films, Self Assembling Monolayers (SAMs), ellipsometry, and atomic force microscopy (AFM). On the silicon wafer with an amino-silaned surface, the monolayers of caldarchaeol-PO₄ remained stable. By using the Langmuir-Blodgett technique and SAMs, the organisations of molecular monolayers of caldarchaeol-PO₄ have been examined. In the Langmuir-Blodgett procedure, surface pressure is carried out in monolayers of more flat, inhomogeneous caldarchaeol-PO₄. A large flat domain is displayed by another way of monolayers caldarchaeol-PO₄ using SAMs. Monolayers caldarchaeol-PO₄ by the Langmuir-Blodgett method appears to be stable and chemically resistant after washing with organic solvent and an additional treatment ultrasonification with various lipid thicknesses of about 2 nm to 6 nm. Conversely monolayers caldarchaeol-PO₄ by SAMs appear less than monolayers caldarchaeol-PO₄ by the Langmuir-Blodgett method, thicknesses varying from 1 nm to 3 nm.