Metal hydrides have recently been proposed for not only hydrogen storage materials but also high-efficiency thermal storage materials. NaMgH3 contains a considerable theoretical thermal storage density of 2881 kJ/kg. However, its sluggish de/re-hydrogenation reaction kinetics and poor cycling stability exhibit unavailable energy efficiency. Doping with active catalyst into NaMgH3 is deemed to be a potential strategy to mitigate these disadvantages. In this work, the enhancement of de/re-hydrogenation kinetics and cycling properties of NaMgH3 is investigated by doping with lamellar-structure 2D carbon-based MXene, Ti3C2. Results shows that introducing 7 wt.% Ti3C2 is proved to perform excellent catalytic efficiency for NaMgH3, dramatically reducing the two-step hydrogen desorption peak temperatures (324.8 and 345.3 °C) and enhancing the de/re-hydrogenation kinetic properties with the hydrogen desorption capacity of 4.8 wt.% H2 within 15 min at 365 °C and absorption capacity of 3.5 wt.%... [more]

The effect of H2SO4 and FeSO4 concentrations and temperature on the efficacy of decontamination of spent ion-exchange resins was estimated. The study was performed on model spent ion-exchange resins purposefully contaminated with hematite and Co-57 radionuclide. It was found that an increase in solution temperature up to 50 °C and the addition of FeSO4 increases the efficacy of decontamination of spent ion-exchange resins by 1 M and 2 M H2SO4 solutions by 1−2 orders of magnitude, whereas the decontamination factor value here is >103. Since under static conditions, the secondary adsorption of Co-57 was observed, the extra washing of ion-exchange resins by 3 M solution of NaNO3 is required. Decontamination under dynamic conditions excludes the secondary adsorption of Co-57, so that the necessity of the extra stage of washing can be skipped. Under dynamic conditions, the consumption of a solution of the composition H2SO4 (1 mol/L) + FeSO4 (0.2 mol/L) is 1.5-fold lower in comparison with t... [more]

The resorcinol (R)-formaldehyde (F) polymerization was carried out in different experimental conditions to obtain RF/Mo doped carbon xerogels with different morphology, porosity and nature and dispersion of metal. Attractive or repulsive electrostatic interactions were forced in the starting aqueous solution of RF-monomers using different synthesis conditions, namely, combinations of cationic or anionic surfactants, Mo-precursors and pH values. The results showed that when both cationic surfactant and Mo-precursor were used at neutral pH, attractive interactions with the anionic RF-macromolecules are favored during polymerization and the final carbon xerogel exhibited the most developed porosity and the strongest Mo-organic phase interaction, leading to deeper Mo-phase reduction during carbonization and the formation of highly-dispersed crystalline nanoparticles of Mo2C. On the contrary, the use of both anionic surfactant and Mo-precursor leads to repulsive interactions, which generate... [more]

Ionic liquids which are often classified as low melting point salts have received significant attention from research groups and industries to be used in a wide range of applications. Many of these applications require thorough knowledge on the thermophysical properties of the ionic liquids before utilizing their full potentials in various fields. In this work, a series of alkylammonium cation and carboxylate anion-based room temperature protic ionic liquids (PILs) were synthesized by varying length of alkyl chain of the cation from diethyl to dibutyl combined with pentanoate, hexanoate and heptanoate anions. These ammonium-based PILs named as diethylammonium pentanoate [DEA][C5], diethylammonium hexanoate [DEA][C6], diethylammonium heptanoate [DEA][C7], dibutylammonium pentanoate [DBA][C5], dibutylammonium hexanoate [DBA][C6] and dibutylammonium heptanoate [DBA][C7] were characterized using Nuclear Magnetic Resonance (NMR) spectroscopy. The thermophysical properties of the PILs namely... [more]

Heterotrophic bacteria are able to form biofilms in water processing systems, adhering to pipe materials and colonizing surfaces. The aim of our research was to identify the critical points in the process of bottled water production at which controls can be applied to prevent, reduce, or eliminate water safety hazards. Microbiological monitoring was conducted using the plate count method and luminometry. To identify the bacterial isolates, we used polyphasic identification based on biochemical tests and molecular analysis using ribosomal RNA. The heterotrophic plate counts were higher in the water filtration station, ultrafiltration (UV) disinfection station, and holding tank. At these points of the industrial process, the water is stagnant or there is poor flow. Molecular analysis identified the bacterial isolates as belonging to Acinetobacter, Agrobacterium, Aeromonas, Brevundimonas, Citrobacter, Enterobacter, Klebsiella, Pantoea, and Rhizobium genera. Bacterial isolates showed vario... [more]

The degradation effect of heat/peroxymonosulfate (PMS) on atrazine (ATZ) is studied. The results show that the heat/PMS degradation for ATZ is 96.28% at the moment that the phosphate buffer (PB) pH, temperature, PMS dosage, ATZ concentration, and reaction time are 7, 50 °C, 400 μmol/L, 2.5 μmol/L, and 60 min. A more alkaline PB is more likely to promote the breakdown of ATZ through heat/PMS, while the PB alone has a more acidic effect on the PMS than the partially alkaline solution. HO• and SO4−• coexisted within the heat/PMS scheme, and ATZ quantity degraded by HO• and SO4−• in PB with pH = 7, pH = 1.7~1. HCO3− makes it difficult for heat/PMS to degrade ATZ according to inorganic anion studies, while Cl− and NO3− accelerate the degradation and the acceleration effect of NO3− is more obvious. The kinetics of ATZ degradation via heat/PMS is quasi-first-order. Ethanol (ETA) with the identical concentration inhibited ATZ degradation slightly more than HCO3−, and both of them reduced the d... [more]

The use of adhesive joints has increased in recent decades due to their competitive features in comparison with other joining methods. They can be used in specific applications where there is no possibility to use alternative connection techniques. Adhesive bonding was used to assemble the prototype of a high-temperature car radiator (operated up to 125 °C) with a total of 12,240 plastic tubes. This work aims to estimate the shear strength of different adhesives intended for bonding the plastics used to assemble the above-mentioned high-temperature radiator. Fourteen commercial adhesives were tested with one thermoset plastic (G11 glass fabric epoxy sheets) and two glass-reinforced thermoplastics (polyamide PA66-GF30 and polyphenylene sulfide PPS-GF40). Tests were conducted according EN 1465 to determine tensile lap-shear strength of bonding. Testing showed that only 4 of the 14 adhesives tested exhibit substantial bonding strength at temperatures above 120 °C and only one is resistant... [more]

Oil leaks into water bodies and increased organic pollutants harm the environment and ecosystem in several ways, and cleaning up oil spills from water bodies is a global challenge. This research aimed to construct modified cellulose nanocrystal (CNC) based aerogels with 3-triethoxysilyl propyl isocyanate (TEPIC) to evaluate their potential application in oil adsorption. Here, a freeze-drying method was employed to make CNC aerogels. The aerogels were characterized using scanning electron microscopy (SEM), Brunauer−Emmett−Teller (BET) analysis, porosity and density measurements, Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA) measurement, compressive strength, and oil adsorption capacity. SEM results confirmed that the aerogels have a largely porous structure, including a community of uniformly interconnected cellulose fibers. Moreover, the studied aerogels had a low density due to the high porosity. Also, the small pore diameter and high specific surface area... [more]

Finding new antibacterial agents from natural products is urgently necessary to address the growing cases of antibiotic-resistant pathogens. Actinomycetes are regarded as an excellent source of therapeutically important secondary metabolites including antibiotics. However, they have not yet been characterized and explored in great detail for their utility in developing countries such as Nepal. In silico molecular docking in addition to antimicrobial assays have been used to examine the efficacy of chemical scaffolds biosynthesized by actinomycetes. This paper depicts the characterization of actinomycetes based on their morphology, biochemical tests, and partial molecular sequencing. Furthermore, antimicrobial assays and mass spectrometry-based metabolic profiling of isolates were studied. Seventeen actinomycete-like colonies were isolated from ten soil samples, of which three isolates showed significant antimicrobial activities. Those isolates were subsequently identified to be Strepto... [more]

To control acid mine drainage (AMD) at source, biochar, a new green and environmentally friendly passivator has been introduced to passivate pyrite. However, the raw material and pyrolysis temperature largely determine the physical and chemical properties of biochar, the causal relationship between biochar and pyrite and the underlying mechanism are still unknown. Here, biochar materials (rice-straw biochar (RSB) and sugarcane bagasse biochar (SBB)) at different pyrolysis temperatures (300−600 °C) were utilized for the passivation of pyrite. The results of our investigations revealed that the passivation ability of RSB was superior to that of SBB. The addition of RSB with higher pyrolysis temperatures could greatly enhance the passivation efficiency of pyrite. RSB-500 (produced at a pyrolysis temperature of 500 °C) achieved the best passivation effect on pyrite. RSB can form Fe-O bonds through C=O bonding with pyrite. Moreover, the addition of RSB created a reducing environment in the... [more]

In traditional casting, sand is used as a mould material to carry heat away from the melt. However, sand has certain disadvantages, such as poor thermal conductivity, burning of binders, undesirable transition resulting in mould failure, and defects in the components. To overcome these limitations, magnetic moulding technology was introduced more than a few decades ago, but the process never achieved the required industrial developments to commercialise this technology. It is essential to reconsider and develop this technology further to use it as a regular production process. In this paper, processing of Al/SiCp composite using magnetic moulding technology is discussed. The heat transfer results of magnetic moulding process are simulated using COMSOL Multiphysics software and compared with the sand casting process. The temperature distribution, thermal conductivity, and phase change have been studied, finding that steel shots as mould materials show better heat transfer results when c... [more]

Biocatalytic processes often provide an ecological alternative to many chemical processes. However, further improvements in terms of the economic efficiency are required. In order to achieve that, the concept of process integration is a promising option. Applying this within a biocatalytic process, a highly integrated apparatus working as a reactive extraction centrifuge was developed and operated. For this purpose, a commercially available extraction centrifuge was modified to implement a biocatalytic reaction. The novel apparatus was used within a multi-enzyme cascade for the production of a natural flavor and fragrance, namely cinnamic ester. The characterization of the reactive extraction centrifuge and the suitable operation conditions for the inlet streams and the rotational speed for a stable operation were determined. Furthermore, different initial substrate concentrations were applied to prove the reaction. The results provide a successful proof of concept for the novel reacti... [more]

Sustainable waste utilization techniques are needed to combat the environmental and economic challenges faced worldwide due to the rising population. Biochars, due to their unique surface properties, offer opportunities to modify their surface to prepare application-specific materials. The aim of this research is to study the effects of biochar surface modification by oxidizing chemicals on biochar properties. Pine bark biochar was modified with sulfuric acid, nitric acid, hydrogen peroxide, ozone, and ammonium persulfate. The resulting biochars’ pH, pH at the point of zero charges, and concentration of acidic and basic sites were determined using laboratory experimentation. Instrumental techniques, such as infrared and X-ray photoelectron spectroscopy, were also obtained for all biochar samples. X-ray photoelectron spectra showed that oxygen content increased to 44.5%, 42.2%, 33.8%, 30.5%, and 14.6% from 13.4% for sulfuric acid, ozone, nitric acid, hydrogen peroxide, and ammonium pers... [more]

Residual sludge is a significant waste resource, and the preparation of biochar achieves sludge disposal. Biochar has a high uptake capacity for phosphate. To prepare a sludge biochar adsorbent for phosphate, sludge was chemically and anaerobically treated in the presence of iron salts and pyrolyzed. We investigated the effects of the pyrolysis temperature and iron salt on the phosphate uptake capacity, finding that the pretreatment of the sludge with iron salts removed intrinsic phosphate, thus improving the uptake ability. The optimal adsorbent, denoted SB-B-Fe, was prepared by pyrolysis at 700 °C and subsequently modified with a 20 g/L iron-containing solution, yielding a phosphate uptake capacity of 0.5 mg/g. Further, the performance of SB-B-Fe remains high at pH 5−9 and is less affected by interfering anions. The sorption kinetics are consistent with the pseudo-second-order kinetic model, suggesting uptake by chemisorption, and the Langmuir model has a saturation capacity of 0.85... [more]

This paper presents the methodology for the preparation of hydrochar obtained from waste materials of natural origin and investigates its applicability for removing mercury ions from aqueous systems. The sorption properties of the obtained hydrochar were investigated in a batch and in a flow-through column system. The hydrochar material was obtained from apple pomace, which was hydrothermally carbonized in 230 °C for 5 h in a hydrothermal reactor. The hydrochar formed in the process was thermally activated with an inert gas flow—CO2. Obtained materials were characterised with XRD, FTIR-ATR, SEM-EDS and nitrogen sorption (BET) analyses, which confirmed the obtaining of a highly porous carbon material with a specific surface area of 145.72 m2/g and an average pore diameter of 1.93 nm. The obtained hydrochar was analysed for sorption of mercury ions from aqueous solutions. Equilibrium isotherms (Langmuir, Freundlich, Dubinin−Radushkevich, Temkin, Hill, Redlich-Peterson, Sips and Toth) and... [more]

Rotated clinching is a novel cold plastic deformation joining process, which is suitable for the multi-point simultaneous joining of sheet metals. However, the effect of various parameters on the mechanical properties of joints using rotated clinching remains unclear. The purpose of this study is to analyse the important parameters that affect the joint’s shearing strength and relationship between them. The relational expression between the four process parameters (die depth, rotation angle, small fillet radius and large fillet radius) and joint shearing strength was established using the response surface method. Additionally, the quantitative relationship between them was expressed by this relational expression, and the significance of process parameters were evaluated using the analysis of variance. The results revealed that the most significant parameter regarding the shearing strength was die depth h, with the contribution of 47.1%, followed by rotation angle α and small fillet rad... [more]

Many different biopolymers are used to stabilize emulsions, of which starch is of particular concern. To improve the characteristics and technical utility of native starch, various types of changes can be made. This article is a report describing the molecular dynamics of water by the low-field nuclear magnetic resonance (LF NMR) of chemically (E 1412 and E 1420) and physically modified starch (LU 1432) gels and the effect of their use on the stability of oil/water emulsions obtained using bovine and porcine fats. The analysis of changes in spin−spin and spin−lattice relaxation times over time showed that the presence of the type of starch modification significantly affects the values of T1 and T2 relaxation times, as well as the correlation times. Research on time-related changes in water binding in oil-in-water emulsions showed that potato starch modified by chemical methods can be used as an emulsifier. Compared to physically modified starch, chemically modified starches have a much... [more]

Graphite/polymer composites are brittle materials, and tool wear, which has a significant impact on the quality of the machined surface of the material, is very serious during the cutting process. In general, the magnitude of the cutting force directly affects the tool wear; the larger the cutting force, the more severe the tool wear, which in turn affects the machined surface quality of graphite/polymer composites. Therefore, in this study, the effects of machining parameters on cutting forces during orthogonal cutting of graphite/polymer composites were investigated using single-factor and multifactor experiments with cutting speed, cutting thickness, tool rake angle, and rounded edge radius as influencing factors, and the parameters were optimized. The obtained results showed that reducing the cutting thickness and increasing the tool rake angle would significantly reduce the cutting force. During the orthogonal cutting process, when the tool had a small edge radius, the cutting for... [more]

Dimethyl carbonate (DMC) is an eco-friendly and sustainable compound with widespread industrial applications. Various extensive routes have been exploited in the chemical industry to produce DMC. However, these routes have several environmental and energy drawbacks. In this study, a promising novel industrial scheme for the synthesis of DMC via the oxidative carbonylation of vaporized methanol with dimethyl oxalate (DMO) as a byproduct is investigated. A methanol conversion of 81.86% and a DMC selectivity of 83.47% were achieved using an isothermal fixed-bed reactor at 130 °C. The DMC is withdrawn at a purity of >99 mol% via pressure-swing azeotropic distillations. Heat integration was performed to optimize energy consumption, reducing the energy requirements by 28%. An economic evaluation was performed for estimating the profitability via cash-flow diagrams, predicting a payback period of 3.7 years. The proposed green process exhibits several benefits, including high profitability and... [more]

An alternative to 5-hydroxymethyl-2-furfural (HMF), which is a promising furan derivative that can be used as a starting material for the preparation of non-petroleum-derived polymeric materials from sugars, is 5-acetoxymethyl-2-furfural (AMF). The less-hydrophilic acetyl group of AMF has advantages over the hydroxy group of HMF in terms of thermal stability and isolation. In previous studies, fructose has been used as a starting material along with lipases for the enzymatic synthesis of AMF. In this study, we designed a hybrid synthesis system that includes the isomerization and esterification of glucose into AMF. For the step-by-step conversion of glucose to 1,6-diacetylfructose (DAF), glucose-isomerase and immobilized lipase (Novozym 435) were used as enzymes. Furthermore, for the synthesis of AMF, the direct dehydration of DAF was performed using a cation exchange resin (Amberlyst 15), combined with several industrial solvents, such as dimethylsulfoxide (DMSO), acetonitrile (AN) an... [more]

TLC combined with densitometry was used, and chromatographic conditions were developed to determination both fluoxetine and sertraline in pharmaceuticals. The mobile phase with the composition of acetone, chloroform, and ammonia (10:5:1, v/v) allowed separation of the most degradation products of sertraline and fluoxetine from all nineteen used in the study of mobile phases. Therefore, this mobile phase was selected as optimal for the analysis of sertraline and fluoxetine in pharmaceutical formulations. The RF values of sertraline and fluoxetine differ from the degradation products of fluoxetine and sertraline. Therefore, the developed chromatographic conditions can be used for the simultaneous determination of fluoxetine and sertraline. Confirmation of the identity of the active substance can be made on the basis of the compliance of the RF values and the spectrodensitograms of the substance from the pharmaceutical preparation and the standard of fluoxetine or sertraline, respectively... [more]

The automation of cell production processes demands strict requirements with regard to sterility, reliability, and flexibility. Robots work in such environments as transporting devices for a huge variety of disposables, e.g., cell plates, tubes, cassettes, and other objects. Therefore, the blades of their grippers must be designed to hold all of these different materials in a stable, gentle manner, and in defined positions, which means that the blades require complex geometries. Furthermore, they should have as few edges as possible, so as to be easy to clean. In this report, we demonstrate how these requirements can be met by producing stainless steel robot grippers by additive manufacturing.

Acyclovir (ACV) is a synthetic acyclic nucleoside analogue active against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2). The current research entails optimization, development, and validation of the sensitive, accurate, and precise high performance liquid chromatography-photo-diode array detector (HPLC-PDA) bioanalytical method for quantification of ACV in rat plasma. The central composite design (CCD) of Design Expert (quality by design tool) was employed for identification of significant attributes (flow rate and concentration of buffer), which affected the performance of the developed method. The elution of ACV was achieved by separating the XBridge C18 column and the mobile phase comprising of the potassium dihydrogen phosphate buffer (pH-6.8) and acetonitrile in a 90:10 v/v ratio pumped at a flow rate of 1.0 mL/ min. The method was validated as per International Council for Harmonization (ICH) guidelines in terms of selectivity, linearity, recovery, accuracy, and precision.... [more]

Impedance spectroscopy has a high potential to detect chemical reactions in flowing systems. In this work, the approach using impedance spectroscopy as a possible analytical tool for a continuous hydrothermal syntheses (CHTS) is presented. With the CHTS-process, it is possible to produce metalloxide nanoparticles with a close particle size distribution and specific surface properties. For this, it is necessary to evaluate the electrode geometry, frequency and other factors influencing the impedance with respect to concentration measurements. In case of frequency-sweep measurements possible electrode geometries for C4D-Sensors (capacitively coupled contactless conductivity detection) are evaluated. Then distinguishability and reproducibility are tested applying titration measurements to show the ability for concentration detection in constant flow systems. The possibility to measure concentration changes in flowing systems in a reproducible and fast manner as well as with high distingui... [more]

Although water contamination with drug residues is a threat to public health, there are currently barely any effective methods of purifying water from pharmaceutical substances. In this study, continuous-flow sonoplasma treatment was used for the complete degradation of tetracycline and ciprofloxacin in polluted municipal water. The addition of CeO2 nanoparticles as catalysts significantly increased the degradation rate of the antibiotics, and a degradation degree of 70% was achieved. The presence of reactive oxygen species in the CeO2-nanoparticle-containing sonoplasma-treated system was experimentally proven for the first time using the chemiluminescence technique.