Submerged arc welding is a complex metallurgical process with a temperature of nearly 2000 ∘C (a temperature much higher than that in traditional steelmaking) and different phases, including flux (slag), metal, and plasma. Flux serves vital functions in order to produce the weld metal with desired qualities. It is well known that understandings of the thermodynamic properties regarding flux and slag are essential to aid in flux design and optimization. Actually, the developments of flux design and thermodynamics have been promoting each other. Within this review, the flux design stages have been documented and reviewed in detail from the perspective of thermodynamics. The thermodynamic design principles for fluxes have been evaluated systematically, the limitations of each flux have been elucidated, and the thermodynamic significance of the designed fluxes upon the development of welding thermodynamics has been analyzed. Based on the hypothesis that thermodynamic equilibrium is attaine... [more]

The conventional disposal of green straws through burning can be eliminated in a biorefinery that converts them into a range of sustainable commercial products. However, this leads to the generation of green straw biorefinery effluent (GSBE). Green straw biorefineries discharge wastewater into the ecosystem that contains high concentrations of COD and NH4+−N. It is one of the most notable sources of visual pollution and disruption of aquatic life as well as public health that requires treatment prior to discharge. To improve the GSBE quality for environmental sustainability, the attainment of sustainable development goals 6, 9, and 14, “clean water and sanitation”, “inorganic and organic waste utilization for added values from material”, and “life below water” is very important. Therefore, the effectiveness of the continuous mode activated sludge (CMAS) system and the biocomposite-based−continuous mode activated sludge (SB-CMAS) system in the treatment of GSBE was investigated in this... [more]

In an attempt to effectively utilize a multitude of surplus sludge from sewage treatment plants, ordinary Portland cement was used to solidify the dry surplus sludge as a building material. The dry surplus sludge and cement were mixed at different proportions with a certain dosage of water and then cured for 3−60 days at room temperature. The unconfined compression strength (RC) of solidified blocks was investigated with respect to the effects of the ratio of liquid to solid (Rl/S), surplus sludge dosage (DS), the dosage of sodium silicate (DNa2SiO3), and the proportion of fly ash (WF). The fabricated solidified blocks were characterized by scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray Diffraction Analysis (XRD). The results demonstrated that RC at 60 days reduced obviously with the increase in Rl/s when Ds was given, whereas RC reduced with DS increased to 15.0 wt% from 5.0 wt% for solidified blocks. When DS was 5.0 wt%, RC of 28 days w... [more]

The development of techniques for coating thermistors with materials possessing excellent chemical resistance and electrical insulation characteristics is necessary to ensure their protection. The present work proposes a coating technique using zirconia (ZrO2), which has excellent chemical resistance and electrical insulation properties, based on initiating a sol−gel reaction of zirconium alkoxide in the presence of a ceramic substrate consisting of the common components of thermistors. The ZrO2 films on substrates were not damaged, even after annealing at 600 °C in air. Several ZrO2 particles were also deposited on the substrate. Pre-silica (SiO2)-coating the substrate, which was performed through a tetraethoxysilane (TEOS) sol−gel reaction, decreased the amount of ZrO2 particles and promoted the formation of thick ZrO2 films, as the reaction between the Zr butoxide and the alkoxyl groups of incompletely hydrolyzed TEOS on the substrate increased the affinity between the ZrO2 layer an... [more]

Organic pollutants (OPs) and heavy metals are environmental toxicants associated with great concerns. Decontamination processes are urgent for both, and the possibility to achieve their simultaneous removal from polluted waters is highly interesting. Additionally, in many cases, the effect of organic matter in the removal process is overlooked and must be considered. This work aimed to study the potential of alginate-based and polycaprolactone (PCL) materials to remove OPs and copper ions in the absence and presence of organic matter. The OPs investigated were the polycyclic aromatic hydrocarbons anthracene and benzo[a]pyrene, and the pesticide chlorpyrifos, both hydrophobic compounds. Copper (II) ions were used as a model of heavy metals. Alginate-based spheres were prepared by gelation, and PCL microparticles were obtained by oil/water emulsion solvent evaporation. The materials with the highest efficiencies for OP removal from aqueous solutions were those with activated carbon and P... [more]

In this study, two shale samples with different maturities, from Geniai, Lithuania (Ro = 0.7%), and Wenjiaba, China (Ro = 2.7%), were selected for open-system pyrolysis experiments at 400 °C and 500 °C, respectively. The generation of isotopic gases from the shales with different maturities was investigated, and the effects of pyrite catalysis on the carbon isotopic compositions were also studied. It was found that CO2, CH4 and their isotopic gases were the main gaseous products of the pyrolysis of both shales, and more hydrocarbon gases were generated from the low-maturity Geniai shale. The δ13C1 values fluctuated from −40‱ to −38‱, and δ13C2 showed higher values (−38‱~−34‱) for the Geniai shale. In addition, its δ13CCO2 values ranged from −28‱ to −26‱. Compared with the Geniai shale, lower δ13C1 values (−43‱~−42‱) and higher δ13CCO2 values (−19‱~−14‱) were detected for the Wenjiaba shale. As temperature increased, CH4 became isotopically lighter and C2H6 became isotopically heavier,... [more]

Considering the importance of environmental protection and renewable energy resources, particularly solar energy, the present study investigates the temperature control of a solar panel using a nanofluid (NFD) flow with eco-friendly nanoparticles (NPs) and a phase change material (PCM). The PCM was used under the solar panel, and the NFD flowed through pipes within the PCM. A number of straight fins (three fins) were exploited on the pipes, and the output flow temperature, heat transfer (HTR) coefficient, and melted PCM volume fraction were measured for different pipe diameters (D_Pipe) from 4 mm to 8 mm at various time points (from 0 to 100 min). Additionally, with the use of artificial intelligence and machine learning, the best conditions for obtaining the lowest panel temperature and the highest output NFD temperature at the lowest pressure drop have been determined. While the porosity approach was used to model the PCM melt front, a two-phase mixture was used to simulate NFD flow.... [more]

The problem needs to be solved about stability control of small coal pillars along goaf in the coal mining process. In this paper, the effects of water reducer, accelerator and expansion agent on the fluidity, setting time, expansion ratio and stone body strength of grouting materials were analyzed through orthogonal experiments, and the optimal ratio of grouting materials was obtained, and it is applied to the engineering site to obtain the reinforcement effect of the coal pillar grouting material on the coal pillar. The results of the study show that: When the dosage of the accelerating agent is 4%, the amount of water-reducer is 0.3%, and the amount of the expansive agent is 6%, the comprehensive performance of the grouting material is the best. After using the new coal pillar grouting material to strengthen the coal pillars, 30 days of monitoring were conducted to determine the deformation of the surrounding rock of the roadway. The shallow separation layer of the surrounding rock... [more]

This review focuses on the role of magnetic nanoparticles (MNPs), their physicochemical properties, their potential applications, and their association with the consequent toxicological effects in complex biologic systems. These MNPs have generated an accelerated development and research movement in the last two decades. They are solving a large portion of problems in several industries, including cosmetics, pharmaceuticals, diagnostics, water remediation, photoelectronics, and information storage, to name a few. As a result, more MNPs are put into contact with biological organisms, including humans, via interacting with their cellular structures. This situation will require a deeper understanding of these particles’ full impact in interacting with complex biological systems, and even though extensive studies have been carried out on different biological systems discussing toxicology aspects of MNP systems used in biomedical applications, they give mixed and inconclusive results. Chemi... [more]

The cuticular lipid compounds, usually named cuticular waxes, present in the cuticular layering of Quercus suber adult leaves were extracted with solvents of different polarities (n-hexane, dichloromethane and acetone) and analysed by GC−MS. Q. suber leaves have a substantial cuticular wax layer (2.8% of leaf mass and 239 μg/cm2), composed predominantly by terpenes (43−63% of all compounds), followed by aliphatic long chain molecules, mainly fatty acids, and by smaller amounts of aliphatic alcohols and n-alkanes. The major identified compound was lupeol (1.2% of leaves in n-hexane extract). The recovery and composition of cuticular lipids depended on the solvent and extraction time. The non-polar or weak polar solvents n-hexane and dichloromethane extracted similar lipid yields (77% and 86% of the total extract, respectively) while acetone solubilised other cellular compounds, namely sugars, with the lipid compounds representing 43% of the total extract. For cuticular lipids extraction... [more]

The catalyst’s photocatalytic activity under sunlight was tested using graphene oxide (GO) from plant cellulose waste and modified by ZnO nanomaterial. The absorbance of the dye’s solution (Rhodamine 6G) was recorded as λmax = 555 nm at regular time intervals. The degradation kinetics of rhodamine was evaluated by applying first-order integrated rate expression, kt = −ln (C/C0). The half-life (t1/2), the rate constant (k), and the time constant τ (Tau) have been obtained by the above rate expression. The rate constant of the reactions carried out with the different materials was calculated and the values obtained were: k_ZnO =1.574 × 10−2, k_GO =1.01 × 10−2 and k_C-GO-ZnO = 4.7 × 10−3 min−1. The degradation efficiency presented by GO, ZnO and GO-ZnO catalysts was 66.67, 70.84, and 70.07%, respectively. FTIR spectroscopy was used to investigate the interactions between the catalyst and the dye. To the best of our knowledge, waste-derived GO-ZnO has not been previously reported for the p... [more]

In this work, protonated forms of potassium polytitanate were obtained by treating the precursor in HCl solution at pH 2.0, 3.0, 4.0, 5.0, 6.0, or 7.0. The synthesized materials were studied using XRD, FTIR, and XRF. The ion-exchange properties were studied using a LiCl solution with a concentration of C(Li+) = 0.01 mol/L. It was shown that extraction of lithium by potassium polytitanates is dependent on their protonation degree. It has been established that the samples with the highest degree of protonation obtained at pH = 2.0 and 3.0 have the highest efficiency in the ion-exchange extraction of Li+ ions from an aqueous solution. For determination of exchange ion rates and the mechanism of the ion-exchange process, pseudo-first- and pseudo-second-order models as well as the Weber−Morris intraparticle diffusion model, were employed. Experimental data with their participation are in good agreement with the pseudo-second-order kinetic model. The calculated kinetic parameters were qe = 0... [more]

Polyurethane foam (PUF) is actively used for thermal insulation. The main characteristic of thermal insulation is effective thermal conductivity. We studied the effective thermal conductivity of six samples of PUF with different types and sizes of cells. In the course of the research, heat was supplied to the foam using an induction heater in three different positions: above, below, or from the side of the foam. The studies were carried out in the temperature range from 30 to 100 °C. The research results showed that for all positions of the heater, the parameter that makes the greatest contribution to the change in thermal conductivity is the cell size. Two open-cell foam samples of different sizes (d = 3.1 mm and d = 0.725 mm) have thermal conductivity values of 0.0452 and 0.0287 W/m⸱K, respectively, at 50 °C. In the case of similar cell sizes for any position of the heater, the determining factor is the type of cells. Mixed-cell foam (d = 3.28 mm) at 50 °C has a thermal conductivity... [more]

In this work, we have successfully fabricated nanocrystalline Co2MnSi Heusler alloy glass-coated microwires with a metallic nucleus diameter (dnuclei) 10.2 ± 0.1 μm and total diameter 22.2 ± 0.1 μm by the Taylor−Ulitovsky technique for the first time. Magnetic and structural investigations have been performed to clarify the basic magneto-structural properties of the Co2MnSi glass-coated microwires. XRD showed a well-defined crystalline structure with a lattice parameter a = 5.62 Å. The room temperature magnetic behavior showed a strong in-plane magnetocrystalline anisotropy parallel to the microwire axis. The M-H loops showed unique thermal stability with temperature where the coercivity (Hc) and normalized magnetic remanence exhibited roughly stable tendency with temperature. Moreover, quite soft magnetic behavior has been observed with values of coercivity of the order of Hc = 7 ± 2 Oe. Zero field cooling and field cooling (ZFC-FC) magnetization curves displayed notable irreversible... [more]

The research aims to produce, model, and optimise the mechanical properties of novel composite material through a structured multidisciplinary approach. The primary objective is to combine materials science, mechanical engineering, and statistical concepts to ensure Design for Manufacturability (DFM) from the industrial perspective. More specifically, the article is intended to determine the optimal mixture components and predictive model of Al-Si alloy with Al2O3 by accommodating multi-responses that enable DFM. The study adopted ASTM standards to prepare and test the novel composite material. Additionally, the Mixture Design of Experiment (DOE) approach was used to design the experimentation and subsequent analysis. In addition, microstructural images, Cox Response Trace plot, and Response Optimiser plot are effectively utilised to draw robust inferences. For multi-response modelling and optimisation, the composite material’s mechanical properties, like impact strength, hardness, den... [more]

The chemical co-precipitation method was used to prepare magnetically separable Fe−Mn oxide composites, and the degradation of p-chloroaniline (PCA) using MnFe2O4 activated peroxydisulfate (PDS). The MnFe2O4 catalyst exhibited highly catalytic activity in the experiments. XRD, FTIR, SEM and TEM were used to characterize the catalytic materials. MnFe2O4 calcined at 500 °C was more suitable as a catalytic material for PCA degradation. The elevated reaction temperature was beneficial to the degradation of PCA in neutral pH solution. The reaction mechanism of the MnFe2O4 catalyzed oxidative degradation of PCA by PDS was investigated by free radical quenching experiments and XPS analysis. The results showed that sulfate radicals (SO4•−), hydroxyl radicals (•OH) and singlet oxygen (1O2) may all be participated in the degradation of PCA. XPS spectra showed that the electron gain and loss of Mn2+ and Fe3+ was the main cause of free radical generation. The possible intermediates in the degradat... [more]

The biodegradation behavior of a ternary alloy Mg-4Li-1Ca (LX41) was investigated. Preliminary studies of the alloys showed that its property profile may qualify it as a material of choice for bioresorbable bone implants. However, no data on the in vivo behavior of the alloy were available to date. Here we report the results on the in vivo response of juvenile growing rats to implantation over a period of 24 weeks based on micro-computed tomography and histology examination. A comparison with an established Mg-Zn-Ca alloy revealed a higher biodegradation rate of LX41. However, LX41 implants were well integrated, and their faster degradation did not negatively affect bone in-growth and morphology. While lower degradation rates are still desirable, especially at the initial stage of bioresorption, the results obtained suggest that the moderate degradation rates observed will not be detrimental to long-term outcomes of LX41 implantation.

In this study, the bioactive components in the stem of Hibiscus taiwanensis S. Y. Hu were extracted by supercritical carbon dioxide (SC-CO2), and the inhibition activity of the extract tyrosinase was analyzed. When the particle size of the powder was controlled to be 50 mesh, the effects of temperatures (40, 45, 50, 55, and 60 °C), pressures (15, 20, 25, 30, and 35 MPa), concentrations of entrainment agent (ethanol) (60, 80, and 95%) and CO2 flow rates (80, 100, 120, and 140 L/min) on the extraction rate, respectively, were studied with the single-variable method. The optimal parameters included an extraction temperature of 55 °C, an extraction pressure of 30 MPa, 80% ethanol as the entrainment agent, and the CO2 flow rate of 100 L/min. Under the optimal conditions, the extraction rate of Hibiscus taiwanensis S. Y. Hu reached more than 0.5% within 2 h. At the same time, the chemical compositions of the extract were investigated by using high-resolution liquid chromatography-mass spectr... [more]

3D bioprinting is an emerging research field developed by the deep cross-fertilization of 3D printing technology with multiple disciplines such as mechanics, materials, and biomedicine. Extrusion 3D bioprinting, the most widely used 3D bioprinting technology, can print biomaterials with different viscosities and has a wide range of material applicability. In this study, we prepared a composite hydrogel with gelatin-oxidized nanocellulose as the matrix and glycerol as a multifunctional co-solvent, and the optimal composition of the hydrogel was determined by material characterization. The microstructure of the hydrogel was visualized by scanning electron microscopy (SEM), and it can be seen that the composite hydrogel material has a three-dimensional porous network structure with microporous pore sizes ranging from 200−300 µm. The infrared spectra also showed that the addition of glycerol did not interact with gelatin-oxidized nanocellulose while improving the hydrogel properties. Meanw... [more]

Rough processing of iron ore employs dry methods which means that equipment is tuned to process large particles, but fine magnetic material less than a few tenths of a millimeter in size is not separated as efficiently. The relevance of this study is determined by the fact that dry beneficiation waste contains recoverable iron-bearing magnetite of commercial value. Commercial justification of waste beneficiation is associated with mining and grinding costs that are already included in the prime cost of the commercial concentrate. The future of tailings retreatment prospects depends on technology and efficiency of the employed equipment, the development of which is the subject of this paper. At first stage, fine iron is recovered by air sizing, with pitched curtain air classifiers embedding simple design and high performance. Powder materials were magnetically separated by a manufactured drum-type separator in which, to increase the separation efficiency, the process was performed at in... [more]

Innovative adhesive formulations have been developed in the laboratory based on urea-formaldehyde resin by adding medicinal plants to an industrial adhesive formulation containing raw materials: urea-formaldehyde resin, urea, ammonium sulphate and starch. Specifically, Thymus species (Thymus bleicherianus, Thymus capitates, Thymus satureioides, Thymus vulgaris and Thymus zygis) replaced part of the starch and were considered as the second filler in the formulations. The physico-chemical properties of the resulting adhesive formulations, such as: pH, viscosity, gel time, solids content, density, concentration of free formaldehyde and color were measured, and characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared spectroscopy (FTIR). In order to evaluate the mechanical performances of adhesive formulations based on plants, plywood panels were produced and their m... [more]

An environmentally friendly, biobased film was prepared from cellulose and lignin extracted from oil palm dried long fiber (DLF). DLF crude cellulose was first extracted from this lignocellulosic biomass by an alkaline pretreatment process at an elevated temperature (5.75 wt% NaOH, 200 °C, and 1 h), before it was carboxymethylated to obtain carboxymethyl cellulose (CMC). CMC is highly soluble in water, whereas lignin was precipitated out of the filtrate of the alkaline pretreatment process by adding acid to pH 2 (50 wt% H2SO4). The lignin/CMC films were synthesized at varying lignin concentrations of 0.25%, 0.5%, and 1% (w/v) in ethanolic solution with 0.25% (v/v) of glycerol; a neat CMC film was also prepared as a control. These lignin/CMC films were evaluated and compared for their morphological, physical, chemical, and thermal characteristics. The films displayed a brownish physical appearance, which was attributed to the natural color of lignin. The successful incorporation of lign... [more]

A quick and accurate chromatographic−densitometric method for the determination of ceftobiprole in biological material (whole blood and urine) was developed. Preparation of the test sample required extraction of the drug from the matrix and was carried out by testing methanol or acetone as extracting agents, which were successfully used to isolate ceftobiprole from biological material. Under optimization of the procedure, various stationary and mobile phases were tested. Lastly, HPTLC cellulose plates and a mixture containing ethanol, 2-propanol, glacial acetic acid, and water in the ratio 4:4:1:3 (v/v/v/v) were chosen. Densitometric detection was made at a maximum absorbance of 316 nm. The developed method was validated; a linear function of the ceftobiprole concentration was obtained in the range of 2.4−72 µg/mL (r > 0.99) for both methanol and acetone solutions. The average accuracy of the devised method was measured at nearly 100%; nevertheless, the limit of the quantification was... [more]

Hydroxyl radical (·OH) is a key component that leads to the cleavage of the glycosidic bond in the process of chitosan (CS) degradation by hydrodynamic cavitation (HC). In this paper, methylene blue (MB) was selected as the trapping agent of ·OH and the yield of ·OH in an impact-jet hydraulic cavitator was investigated. The results showed that the cavitation intensity and the number of passes (N) were the two main factors affecting the yield of ·OH. A smaller cavitation number (Cv) or a larger N indicated that more ·OH can be produced. Based on the dimensionless number correlation method, the yield of ·OH was correlated with Cv, N, Euler number (Eu), Reynolds number (Re), and a dimensionless parameter (γ), and a prediction model of ·OH yield was established. The relative deviations between the experimental and calculated values of the ·OH yield were basically within 10% by the prediction model. On the basis of the prediction model, the yield of ·OH produced in the process of CS degrada... [more]

With their relative ease of production and coupled strong surface functionality and electrical conductivity properties, graphene oxide (GO) and reduced graphene oxide (rGO) are exciting, yet overlooked, graphene-like additive prospects for activated carbon (AC) electrodes in supercapacitors. In this work, we incorporated small amounts of synthesized GO and rGO in AC electrodes via a simple mixing procedure to explore their effects. In addition to materials characterizations, symmetric supercapacitors were made from these electrodes and tested across current densities ranging from 0.1−10 A g−1 and across 10,000 additional charge-discharge cycles at 2 A g−1. Performance measurements indicate that GO and rGO enhance the rate resistance and capacity, respectively, of AC electrodes, but these effects are modest and do not prevent increases in internal resistance over the course of 10,000 cycles. The overall ineffectuality of GO and rGO is reasoned to be due to their isolation and infrequenc... [more]