The uncontrolled release of synthetic toxins and micropollutants from industry and consumer sources into freshwater bodies poses a serious risk to aquatic environments and human health. Advanced oxidation processes, specifically heterogeneous photocatalysis, have drawn attention to solve these issues and a possible route to improve the quality of the aquatic environment. This has been obtained by investigating unique materials that can function synergistically with one another. The scientific society has explored different photocatalyst types. Nevertheless, heterojunction photocatalysts in general and binary heterojunction photocatalysts in particular have demonstrated remarkable qualities and unique advantages. The combined impacts of metal oxides (MOx) and metal sulfides (MS) have a dominant synergistic effect. Therefore, metal oxide/metal sulfide heterojunctions are emerging as revolutionary photocatalysts in environmental solutions. Binary composites such as ZnO/ZnS, CuO/CuS, ZnO/CuS, and many others are discussed for their synergetic photocatalytic efficiencies in the degradation of a variety of pollutants, including insecticides, dyes, pesticides, antibiotics, and heavy metals. This review explores multifaceted roles of MOx/MS highlighting the potential of these heterojunctions as a promising pathway towards a more sustainable future. Further, a detailed understanding is provided on how heterojunctions have been employed to catalyze environmental remediation by investigating their different electrical interactions and catalytic capabilities. Finally, the manuscript will recommend guidelines for further advancement in this rapidly evolving, multidisciplinary field of current interest.

The declaration of the movement control order (MCO) in Malaysia has led to the closure of the education sector due to pandemic coronavirus disease 2019 (COVID-19). The teaching and learning (T&L) structure shifted from conventional classroom education to fully online distance learning (ODL). The unprecedented experience of 'home quarantine' has multifaced impacts on students' mental health. The study aimed to obtain the correlation of technical and vocational education and training (TVET) students' depression, anxiety, and stress (DAS) in fully implementing online distance learning. A survey study was used using a quantitative approach and respondent was evaluated by the depression anxiety stress scale-21 (DASS-21). Understudy's t-test and one-way analysis of variance (ANOVA) were utilized to investigate the relationship between these perspectives. Analysis from the DASS-21 inventory revealed that 30% had severe or extremely severe depression, 41% anxiety, and 20% stress among the vocational students. Anxiety showed a hugely significant difference among genders and the department compared to depression and stress. Therefore, the finding suggests that some intervention must ensure online distance learning is conveniently accessible and congenial with practical work for the vocational student syllabus. © 2022, Intelektual Pustaka Media Utama. All rights reserved.

The objects of research are the designs and manufacturing technologies of a combined fiber-optic sensor. It is used in extreme operating conditions. The essence of the task is to study the constructive and technological compatibility of optical and micromechanical principles of simultaneous measurement of several heterogeneous physical quantities. In this regard, the chosen modular conversion principle solves the problem of combined conversion. The developed design and technology of the electro-adhesive connection make it possible to significantly reduce the internal mechanical stresses in the sensor and thereby increase the stability of the combined sensors in extreme operating conditions. Analytical models linking the magnitude and orientation of internal mechanical stresses with the characteristics of temporary stability for complex structures, as a rule, are absent. In practice, the obtained research results can be applied to combined pressure and temperature sensors, pressure and vibration, etc. © 2022, Authors. This is an open access article under the Creative Commons CC BY license

In downhole oil production, a column of pumping and compressor tubing’s is equipped with various operational and technological valves for their intended purpose. Each of these valves has a specific function. Therefore, the basic tubing arrangement may not initially contain a specific valve, the need for which may arise for individual operations during repair and maintenance work. This makes it necessary to carry out labor-intensive work involving special equipment for stopping and silencing wells, lifting underground equipment, completing tubing with the necessary technological valve and its descent into the well. The paper proposes to simplify the layout of a downhole pumping unit and increase its technological capabilities by equipping it with a multifunctional valve, which will allow performing both operational tasks and a wide range of necessary technological operations directly in the well without lifting equipment. © 2024, National Academy of Sciences of the Republic of Kazakhstan. All rights reserved.

The energy of cyanobacterial hydrogen (H2) produced via bio-photolysis is being investigated as a potential solution to early-century environmental challenges. The main limiting factors of cyanobacterial H2 photoproduction are the availability of electrons for [NiFe]-hydrogenase (H2ase) and the suppression of bidirectional H2ase activity induced by O2 acquired from water molecules splitting in photosystem II. The current study investigated how photosynthetic inhibitors (PIs) affected H2 production in non-N2-fixing cyanobacteria. Study findings revealed a rather high H2 yield in Synechocystis sp. PSU 1262, as well as a beneficial (14.2-fold) influence of 500 μmol KCN on the H2 production by the aforesaid strain. A 12/6-h light/dark cycle increased H2 production by 80.3% in cells supplemented with 500 μmol KCN. Under the optimised conditions, the photobiological H2 production of Synechocystis sp. PSU 1262 increased from 49.6 to 1552 nmol H2 mg−1 Chl a h−1. PIs suppressed chlorophyll a concentration under illumination, lowering the O2 levels, which enhanced bidirectional H2ase activity in Synechocystis sp. PSU 1262 cells. Applying varied light modes, preceded by the incorporation of PIs at optimal concentrations in H2 production by research cyanobacterial strains, improved the H2 yield and contributed significantly to the research originality. © 2023 Hydrogen Energy Publications LLC

The increasing demand for sustainable and efficient energy storage materials has led to significant research into utilizing waste biomass for producing activated carbons. This study investigates the impact of the structural properties of activated carbons derived from various lignocellulosic biomasses—barley straw, wheat straw, and wheat bran—on the electrochemical performance of supercapacitors. The Fourier Transform Infrared (FTIR) spectroscopy analysis reveals the presence of key functional groups and their transformations during carbonization and activation processes. The Raman spectra provide detailed insights into the structural features and defects in the carbon materials. The electrochemical tests indicate that the activated carbon’s specific capacitance and energy density are influenced by the biomass source. It is shown that the wheat-bran-based electrodes exhibit the highest performance. This research demonstrates the potential of waste-biomass-derived activated carbons as high-performance materials for energy storage applications, contributing to sustainable and efficient supercapacitor development.

This article presents the results of implementing a digital signal processing method for analyzing the acoustic emission (AE) signature and detecting defects such as cracks and pores. The signal processing method is based on a cascade connection of digital high-pass filters and ensures the selection of informative signals and increases the signal-to-interference ratio. In order to control the formation of defects in the process of selective laser melting, the paper presents the results of experimental testing of the cascade filtration method for detecting defects in the internal structure such as cracks and pores. The signal components recorded during the development of defects during the growth of additive manufacturing products were extracted. AE signatures were analyzed and statistical relationships were assessed. The relationship between the parameters of the AE signal and the values of laser radiation power has been identified, which characterizes the process of defect formation. © 2024 IEEE.

The article presents the analysis and stability program of the closed non-linear system frequency converter-brushless motor “(FC-BM)”, which differs significantly from the analysis of linear systems. First of all, this is because the stability property of a nonlinear system depends on the initial conditions and external influences: for some input signals, the system will be stable, while for others it becomes unstable. Consequently, the stability criteria developed in the linear theory cannot be applied to their analysis. The stability of a non-linear automatic control system means that small changes in the input signal or disturbances, initial conditions, or plant parameters will not take the output variable beyond a sufficiently small neighborhood of the equilibrium point or limit cycle. Since several equilibrium positions can exist for a non-linear system, stability should be analyzed in the vicinity of each of them. This complicates the task of research.

The excessive use of wood as a raw material in furniture industries has raised environmental concerns that have attracted the attention of many individuals. Consequently, various innovations have been explored in developing alternative materials for the furniture industry. One promising resource that has the potential to be developed as a raw material for furniture applications is Nipah palm husk. Nipah palm husk is classified as an agricultural waste that is barely used within society and industries. Hence, in this study, Nipah palm husk will be utilized as the primary material to fabricate particle board by involving tapioca as an adhesive. This research aimed to investigate the effect of tapioca concentrations on water absorption, modulus elasticity, modulus of rupture, and screw-holding strength of the produced Nipah palm husk particleboard. The results of this study showed that the particle board produced with a 40% tapioca adhesive concentration exhibited the most favorable physical and mechanical properties with a water absorption rate of 25%, an elastic modulus of 21188.93 kg/cm2, a modulus of rupture of 55.53 kg/cm2, and a screw holding power of 7.53 kg. The findings indicated that Nipah-based particle board has the potential to be developed as an alternative for the furniture industry. © 2023, Universitas Negeri Padang. All rights reserved.

The results of comprehensive research on the status of sewage treatment in Almaty are presented in this article. The results of the reconstruction and modernization of treatment facilities intended to improve the sewage treatment efficiency, including the results of pretreatment of wastewater with excess sludge in the primary clarification tank, and the results of hydrobiological and microbiological analysis of activated sludge in the aeration tank are presented. The analysis of the study results of the chemical composition of incoming, clarified and treated wastewater is presented. Besides, the results of the analysis of the water balance of wastewater are presented © 2022. Journal of Ecological Engineering. All Rights Reserved.