The effects of ultrasonic treatment (UT)-assisted transglutaminase (TGase) catalysis on the physicochemical properties of individual αs-casein (αs-CN), β-casein (β-CN), and κ-casein (κ-CN) were investigated. After 60 min of incubation at 30 °C, αs-CN, β-CN, and κ-CN were cross-linked with TGase (6.0 units/mL), and high molecular weight polymers (>200 kDa) were formed. The use of TGase in conjunction with UT (20 kHz, power of 400 W, and amplitude 20%) led to an increase in the rate of αs-CN, β-CN, and κ-CN polymerization compared to the individual casein that contained TGase but did not undergo UT. SDS-PAGE scrutiny showed that the intensities of αs-CN, β-CN, and κ-CN incubation with regard to TGase and UT at 30 °C for 60 min noticeably decreased to 5.66 ± 0.39, 3.97 ± 0.43, and 26.07 ± 1.18%, respectively (p < 0.05). Particle size analysis results indicated that the molecule size appropriation for the cross-linking of αs-CN, β-CN, and κ-CN ranged from 6000 to 10,000 nm after 60 min... [more]

Hydroquinone (HDQ) is a natural depigmenting agent, which is commonly used in skin-toning preparations. The safety and greenness of analytical methods of HDQ quantification were not considered in previous literature. Therefore, a highly sensitive and ecologically greener reversed-phase high-performance thin-layer chromatography (RP-HPTLC)-based assay was established for HDQ estimation in four different commercial whitening creams (CWCs). The binary ethanol−water (60:40, v·v−1) mixture was utilized as the green solvent system. The estimation of HDQ was carried out at 291 nm. The present RP-HPTLC-based assay was linear in the 20−2400 ng band−1 range. The present analytical method was highly sensitive based on the detection and quantification data. The other validation parameters, such as accuracy, precision, and robustness, were also suitable for the determination of HDQ. Maximum HDQ quantities were obtained in CWC A (1.23% w·w−1) followed by CWC C (0.81% w·w−1), CWC D (0.43% w·w−1), and... [more]

Reduction of fluid resistance using the rheological characteristics of a polymer-surfactant solvent is research that contains many aspects, such as the theory of the drag reduction process, historical journey, and ongoing current research development. Many studies have been conducted, but it is challenging to know all existing and new research threads. The present investigation was conducted using literature studies regarding drag reducing agents. This research will also discuss the characteristics of flowing fluids and their effects on the velocity profile with friction factor of flowing fluids in smooth circular straight pipe geometries based on experimental, theoretical approaches. It concludes with aspects of research conducted around reducing drag using drag reducing agents, ideas about innovations, structuring overlook in testing, and modification of the fluid flow state.

The use of metal oxides as supports for palladium and copper (Pd−Cu) nanoalloys constitutes a new horizon for improving new active catalysts in very important reactions. From the literatures, Pd-based bimetallic nanostructures have great properties and active catalytic performance. In this work, nanostructures of titanium dioxide (TiO2) were used as supports for Pd−Cu nanoparticles catalysts. Palladium and copper were deposited on these supports using the sol-immobilisation method. The composite nanoalloys were characterized using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalyst was evaluated for the oxidation of benzyl alcohol. The effect of the Cu−Pd ratio using sol-immobilization methods supported on TiO2 was investigated. The results show that monometallic Cu/TiO2 was observed to have a low activity. However, as soon as the catalyst contained any palladium, the activity increased with a significant increase in the selectivity towards i... [more]

Biochar can be derived from a wide variety of organic materials including agricultural wastes and residues, animal wastes, municipal solid wastes, pulp and paper mill wastes, and sewage sludge. Its productivity relies on feedstock type and thermochemical conditions of production. Biochar has many application advantages in several fields and has been widely studied in recent years. However, most of these studies are mainly on the powder form of biochar, while its pelleted form is sparsely reported. Even with the reported studies on biochar pellets, there is still lack of knowledge and awareness of the effects of different feedstock on the densification behavior of biochar. The mechanisms of biochar densification, which appear to be sensitive to the conditions predominating during its thermochemical production, are affected by the material from which the biochar is derived. This partly accounts for why biochar pellets have not been widely adopted in various application fields. Therefore,... [more]

In the study of block copolymers, many parameters need to be adjusted to obtain good phase separation results. Based on block copolymer polystyrene-b-polycarbonate and homopolymer polystyrene, the effects of the annealing atmosphere, blending ratio, and molecular weight on phase separation were studied. The results show that annealing in air can inhibit the occurrence of phase separation. In addition, snowflake patterns are formed during phase separation. The blending ratio affects the quality of the pattern. The molecular weight affects the size of the pattern, and the size increases as the molecular weight increases. In this article, the influence of process conditions and materials on phase separation was discussed, which has laid a solid foundation for the development of block copolymer self-assembly in the future.

Friction materials, mainly made of reinforced composites, should possess excellent physical and tribological properties, such as a higher coefficient of friction, minimum wear, adequate surface hardness, and higher porosity for various automotive brake applications. Attainment of those properties greatly depends on the settings of different input parameters, such as molding pressure, temperature and time, temperature and time of heat treatment/sintering, etc., during the processing of friction materials. In this article, four multi-criteria decision-making (MCDM) tools, i.e., technique for order of preference by similarity to ideal solution (TOPSIS), evaluation based on distance from average solution (EDAS), VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), and multi-objective optimization on the basis of ratio analysis (MOORA) are applied to identify the optimal parametric combinations for two different friction materials. A comparative analysis of the derived results sugg... [more]

As the anaerobic digestion of energy crops and crop residues becomes more widely applied for bioenergy production, planners and operators of biogas plants, and farmers who consider growing such crops, have a need for information on potential biogas and methane yields. A rich body of literature reports methane yields for a variety of such materials. These data have been obtained with different testing methods. This work elaborates an overview on the types of data source available and the methods that are commonly applied to determine the methane yield of an agricultural biomass, with a focus on European crops. Limitations regarding the transferability and generalisation of data are explored, and crop methane values presented across the literature are compared. Large variations were found for reported values, which can only partially be explained by the methods applied. Most notably, the intra-crop variation of methane yield (reported values for a single crop type) was higher than the in... [more]

Magnetic abrasive finishing (MAF) is a fast, high efficiency and high-precision polishing method on the surface machining of the metals. Furthermore, MAF also can be utilized to polish the stainless tubes in industrial applications; however, stainless tubes are often a non-magnetic material that makes it difficult for the magnetic field line to penetrate into the stainless tubes, thus reducing the magnetic forces in the inner tubes polishing. That is why stainless tubes are not easy to finish using traditional MAF. Therefore, magnetic finishing with gel abrasive (MFGA) applies gels mixed with steel grit and abrasives that were developed to improve the polishing efficiency and surface uniformity of the steel elements. In this study, a guar gum or silicone gel mixed with steel grit and silicon carbides are used as the magnetic abrasive gel to polish the stainless inner tubes. A DC motor was used to control the rotation speed of the chuck and an AC induction motor connected with an eccent... [more]

Iron oxide nanoparticles were employed to fabricate a soft tissue scaffold with enhanced physicochemical and biological characteristics. Growth promotion effect of L-lysine coated magnetite (Lys@Fe3O4) nanoparticles on the liver cell lines was proved previously. So, in the current experiment these nanoparticles were employed to fabricate a soft tissue scaffold with growth promoting effect on the liver cells. Lys@Fe3O4 nanoparticles were synthesized via co-precipitation reaction. Resulted particles were ~7 nm in diameter and various concentrations (3, 5, and 10 wt%) of these nanoparticles were used to fabricate nanocomposite PCL fibers. Electrospinning technique was employed and physicochemical characteristics of the resulted nanofibers were evaluated. Electron micrographs and EDX-mapping analysis showed that nanoparticles were well dispersed in the PCL fibers and no bead structure were formed. As expected, incorporation of Lys@Fe3O4 to the PCL nanofibers resulted in a reduction in hydr... [more]

Human melanoma cells are known as one of the most aggressive cancer cells, and consequently, melanoma is one of the most incurable cancer diseases. There is intense activity in research and development of potential medicines for malignant diseases, including alternative forms of remedies. Therefore, the purpose of our work was testing extracts from the common houseleek (Sempervivum tectorum) grown in Slovenia to establish its impact on human melanoma cells. Namely, we wanted to verify if the extracts inhibit growth of malignant cells and their metabolic activity. Soxhlet, cold solvent, ultrasound, and supercritical extraction methods were applied to obtain S. tectorum extracts. Polyphenols and proanthocyanins content in acquired extracts was determined as well as their antioxidative potential. For a relevant comparison, Chinese (CHI) dried and Slovenian (SLO) lyophilized S. tectorum was used. Results showed that the highest contents of polyphenols and proanthocyanins were yielded from... [more]

In addition to bubble number density, bubble size distribution is an important population parameter governing the activity of acoustic cavitation bubbles. In the present paper, an iterative numerical method for equilibrium size distribution is proposed and combined to a model for bubble counting, in order to approach the number density within a population of acoustic cavitation bubbles of inhomogeneous sizing, hence the sonochemical activity of the inhomogeneous population based on discretization into homogenous groups. The composition of the inhomogeneous population is analyzed based on cavitation dynamics and shape stability at 300 kHz and 0.761 W/cm2 within the ambient radii interval ranging from 1 to 5 µm. Unstable oscillation is observed starting from a radius of 2.5 µm. Results are presented in terms of number probability, number density, and volume probability within the population of acoustic cavitation bubbles. The most probable group having an equilibrium radius of 3 µm demon... [more]

Industrial processes and anthropogenic activities generate huge amounts of wastes in the form of chemicals, such as heavy metals, dyes, fertilizers, pharmaceutically active chemicals, battery effluents and so on. When these chemicals are left untreated and discarded in the ground or surface waters, they not only cause pollution and harm the ecosystem but also cause toxic effects on the health of human beings, animals and food crops. There are several methods of removal of these toxic materials from the wastewaters, and adsorption by bio-sorbents has been demonstrated as one of the most inexpensive, efficient and convenient methods. Citrus is one of the largest grown fruit crops in the tropical and subtropical regions on the planet. After processing of the fruits at food processing industries, approximately half of the fruit mass is discarded as waste, which causes a number of pollution problems. Alternately, this biomass can be converted to bio-sorbents for the removal of harmful and t... [more]

Continuous small-scale production is currently of utmost interest for fine chemicals and pharmaceuticals. For this purpose, equipment and process concepts in consideration of the hurdles for solids handling are required to transfer conventional batch processing to continuous operation. Based on empirical equations, pressure loss constraints, and an expandable modular system, a coiled flow inverter (CFI) crystallizer with an inner diameter of 1.6 mm was designed. It was characterized concerning its residence time behavior, tested for operation with seed crystals or an ultrasonic seed crystal unit, and evaluated for different purging mechanisms for stable operation. The residence time behavior in the CFI corresponds to ideal plug flow behavior. Crystal growth using seed crystals was demonstrated in the CFI for two amino acids. For fewer seed crystals, higher crystal growth rates were determined, while at the same time, secondary nucleation was observed. Feasibility for the interconnectio... [more]

Combining biochar with chemical fertilizers or compost not only improves the shortcomings of biochar’s lack of fertility, but also extends the benefits of the compost. The application of biochar composite materials will be a future agricultural management strategy. In this study bagasse compost was mixed with wood biochar (w/w) at rates of 0% (B), 25% (BC), 50% (BC3), and 100% (no biochar, C) to produce four types of particle biochar compound materials (pBCM). These materials were applied to two types of soil (sandy soil and clayey soil) for a 180-day incubation to determine the decomposition rate and the nutrient release efficiency of the pBCMs. The results showed that C treatment had the highest decomposition rate in both types of soil. Overall, the materials decomposed faster in the sandy soil than in the clayey soil. Plants were grown over two 30-day crop periods. The plant yields of treatments C and BC3 were the highest in the first period and respectively decreased and increased... [more]

Temperature stress analysis is of prime importance to ensure the adequate servicing of super-long frame structures during their service life. The existing design codes and recommendations for reinforced concrete (RC) structures provide methodologies for the reinforcement of design elements that neglect differences in the linear expansion coefficients of steel and concrete. In this paper, we present a numerical method based on a degenerated three-dimensional solid virtual laminated element for simulating and analyzing the temperature stress of a two-layer super-long frame reinforced concrete structure subjected to allover cooling action, whereby the difference in the linear expansion coefficients of steel and concrete are taken into consideration. The results show that the difference in the linear expansion coefficients of steel and concrete, with different constraints, affects the temperature stress experienced by each material in the structure, and this difference adversely affects at... [more]

New resources of food, pharmaceuticals or biotechnological products are needed. The huge biodiversity of aero-terrestrial lichen-symbiont microalgae belonging to the Chlorophyta group remains unexplored despite they present interesting features such as extreme stress tolerance and growth in water shortage. Appropriateness for human consumption demands the demonstration of the absence of toxic effects. In vitro biocompatibility of crude homogenates of axenic microalga Asterochloris erici, isolated from the lichen Cladonia cristatella, was analyzed after treatment of cultured L929 fibroblasts with different concentrations of microalgal homogenates. The microalgal protein content (37%) was similar to spirulina or soybean. Antioxidant capacity (10.6 ± 0.6 µmol TE/g WW) or phenolic content (7.5 ± 0.5 mg GAE/g DW) were high compared to Chlorella. The results show that crude homogenates of A. erici do not induce cytotoxicity but seem to have some cytostatic effect inducing slight cell cycle a... [more]

With a rapidly increasing amount of waste, waste management is an extremely important issue. Utilising processes such as combustion and biological processing significantly decreases the accumulation and volume of waste. Despite this, huge volumes of resulting waste that still need to be managed remain. This paper identifies various methods of processing organic waste, discussing both thermal and biological techniques for waste management. Additionally, this paper demonstrates that the end products remaining after processing waste are oftentimes functional for agricultural use. These materials are excellent byproducts used to produce various organic, mineral and organomineral fertilisers. For instance, it appears that the production of fertilisers is the most promising method of utilising fly ash that results from the combustion of waste. In order to minimise the environmental risk of polluting soil with heavy metals, waste, as well as ashes resulting from combustion, must meet the crit... [more]

Antibiotics, nowadays, are not only used for the treatment of human diseases but also used in animal and poultry farming to increase production. Overuse of antibiotics leads to their circulation in the food chain due to unmanaged discharge. These circulating antibiotics and their residues are a major cause of antimicrobial resistance (AMR), so comprehensive and multifaceted measures aligning with the One Health approach are crucial to curb the emergence and dissemination of antibiotic resistance through the food chain. Different chromatographic techniques and capillary electrophoresis (CE) are being widely used for the separation and detection of antibiotics and their residues from food samples. However, the matrix present in food samples interferes with the proper detection of the antibiotics, which are present in trace concentrations. This review is focused on the scientific literature published in the last decade devoted to the detection of antibiotics in food products. Various extr... [more]

In this paper, reduced graphene oxide (RGO) was prepared by a modified Hummers method and chemical reduction method, and an RGO/TiO2 NTs (RGO/TiO2 nanotubes) photoelectrode was prepared by the electrochemical deposition method. The as-prepared RGO/TiO2 NTs were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their photocatalytic activities were investigated by measuring the degradation of methylene blue (MB) under simulated solar light irradiation. The SEM and XRD results indicated that the original tubular structure of TiO2-NTs was not changed after RGO modification. The surface of the TiO2 NTs photoelectrode was covered with a non-uniform, flake-shaped reduced graphene oxide film. The thickness of the RGO/TiO2 NTs was increased to about 22.60 nm. The impedance of the RGO/TiO2 NTs was smaller than that of the TiO2 NT photoelectrode. The optimal preparation conditions of RGO/TiO2 NT photoelectrodes were investigated by using a single factor method and re... [more]

Microalga-based fuels are promising solutions for replacing fossil fuels. This feedstock presents several advantages such as fast growth in a harsh environment and an ability to trap gases emitted from industries, thus reducing global warming effects. An efficient way to convert harvested microalgae into biofuels is hydrothermal liquefaction (HTL), which yields an intermediate product called biocrude. In this study, the elemental and molecular compositions of 15 different HTL biocrudes were determined by means of different techniques. Wild algae were cultivated in an industrial environment with plant emissions as a carbon source in fresh or seawater. It was notably observed that the culture medium had an influence on the biochemical composition and mineral matter content of algae. Thus, seawater algae were characterized by larger amounts of carbohydrates and mineral matter than freshwater ones, which also affected the oil yields and the light and heavy fractions of biocrudes.

In recent work, deep eutectic solvents (DESs) as ionic liquid analogues have been abundantly used in catalysis. Herein, vanadium phosphorus oxide (VPO) catalysts were synthesized from mono-, bi-, and tri- metallic DES of Nb, Zr, and Mo metal dopants as structure-directing agents and electronic promoters for n-butane selective oxidation towards maleic anhydride. Higher MA selectivity and larger n-butane conversion was successfully obtained using the newly developed catalysts, while oxidation by-product COx (CO, CO2) was minimized. Characterization techniques including FTIR, DSC, XRD, TEM, SEM, EDS, Raman spectroscopy, TGA, XPS, and NH3-TPD were employed to fully characterize the DESs, precursors and catalysts. This work led to an increase of 7.8% in MA mass yield with 16% more n-butane conversion as compared to an unpromoted VPO catalyst. Moreover, the utilization of a low-carbon alkane brought in a green impact on the chemical plant as well as the environment.

It was experimentally established that the dependence of the partial pressure of methanol on the molar fraction of methanol in oil shows a pronounced negative deviation from Raoul’s law, which significantly changes the idea of the influence of a large excess of methanol during non-catalytic synthesis of biodiesel. The efficiency of use of a molar excess of methanol is reduced as it grows, and with a more than 10-fold molar excess of the amount of reacted methanol, is practically constant. The comparison of biodiesel production processes in the range 220−235 °C showed that a slight change in the process temperature more effectively affects the biodiesel yield than an increase in the molar excess of methanol. A mathematical model of the process of transesterification of rapeseed oil in reactors of various types (batch and tubular reactors) is developed. A satisfactory correlation between the experimental and calculated data was observed. The calculation showed that the rate constants of... [more]

This paper describes the important significance of cutting-edge technology in the machining of polycrystalline diamond (PCD) cutting inserts by comparing the evaluation criteria. The LASER technology of cutting-edge machining is compared with grinding and electrical discharge machining (EDM) technologies. To evaluate the data from the experiments, the Grey Relational Analysis (GRA) method was used to optimize the input factors of turning to achieve the required output parameters, namely the deviation of roundness and chip cross-section. The input factors of cutting speed, feed rate, depth of cut and corner radius were applied in the experiment for three different levels (minimum, medium and maximum). The optimal input factors for turning of aluminum alloy (AW 5083) were determined for the factorial plan according to Grey Relational Grade based on the GRA method for the multi-criteria of the output parameters. The results were confirmed by a verification test according to the GRA method... [more]

Graphite/polymer composites are brittle materials that are prone to producing cracks and concavities on machined surfaces, and their surface quality shows greater randomness. This work aims to overcome the large fluctuations in the machined surface quality of graphite/polymer composites, realize the prediction of machined surface roughness under different machining conditions and optimize the process parameters. A graphite/polymer composite material was cut orthogonally using different machining parameters, and the machined surface roughness of the cut samples was measured by a noncontact surface profiler to obtain training samples for Artificial Neural Network (ANN). In this study, a trained radial basis function neural network was used to predict the machined surface roughness, and the prediction accuracy was more than 93%. A Genetic Algorithm (GA) was used to optimize the established ANN, and then grey relational analysis was used to compare the accuracy of the GA optimization resul... [more]