This work analyses 10 adsorption isotherm models applied to adsorption of Cr(III) and Cu(II) from binary solutions on electron-irradiated sheep wool (0-24-100) kGy. The results are compared with fitting the same adsorbates from corresponding single solutions. The competing cation significantly changes the fitting of the selected isotherms to the extent that even simultaneous fitting of the same cation in the single and binary solution is rare. In the case of Cr(III), 4 favourable matches were found out of 30 compared cases, while in the case of Cu(II), only 2 conformities were found. Having the Cr(III) coordination number exclusively of 6, but Cu(II) up to 4, 5, 6, the last coordinates more easily with the ligands provided by keratin, resulting in preferential chemisorption. If there is still a lack of cysteic acid in the wool to interact with Cr(III) also, this is adsorbed on the wool physically, too. The amount of cysteic acid increasing in the wool with the absorbed dose of energy i... [more]

High-chromium vanadium residue (HCVR (HCVR: high-chromium vanadium residue)) is an important secondary resource of valuable metals such as vanadium (V), chromium (Cr), and molybdenum (Mo). The mainstream technology for the utilization of HCVR, the Na2CO3-assisted-roasting−water-leaching method, usually requires roasting temperatures of more than 800 °C and results in the synchronous leaching of Cr with V and Mo. This makes the subsequent separation of V, Mo, and Cr in the aqueous system difficult. In this study, an efficient and clean process for the selective separation of Cr and stepped recoveries of V and Mo from HCVR is proposed via K2CO3-mediated carbonation conversion. Using this process, the roasting temperature can be reduced from more than 800 °C to 200 °C, and 83.14%, 99.94%, and 0.33% of V, Mo, and Cr, respectively, can be leached. Further, using the weakly alkaline ammonium-salt and sulfide precipitation methods, 98.28% pure V2O5 and 98.65% pure MoS2 can be obtained and the... [more]

Phase equilibria in the Ti-Nb-Mn ternary system at 1173K, 1273K and 1373K were studied through the equilibrated alloy method by using scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) techniques. A new stable ternary phase K was confirmed and the composition was around Ti50Nb7Mn43. A wide-range continuous solid solution phase (Ti,Nb)Mn2 with the C14 Laves structure had been found at these temperatures due to the same phase structures of TiMn2 and NbMn2 phases. The solubility of Nb in TiMn4, αTiMn and βTiMn intermetallic compounds was determined. Based on the experimental results and reasonable extrapolations, the isothermal sections of Ti-Nb-Mn ternary system at 1173K, 1273K and 1373K were constructed.

To date, the fracture behaviour of soft, polyurethane-based adhesive joints has rarely been investigated. This work contributes to the experimental investigation of such joints in modes I and III by performing double cantilever beam (mode I) and out-of-plane loaded double cantilever beam (mode III) tests at various loading rates. The tests were evaluated using a J-integral method, which is well established for testing stiff adhesive layers and is conventionally used to determine the cohesive traction at the crack tip. Additionally, fibre-optics measurements were conducted to provide crack extension, process zone length, and cohesive traction from the measured backface strain of the adherends. It was found that the energy release rate seems to be largely independent of the loading mode. However, differences were observed regarding process zone length and resistance curve behaviour. Furthermore, the backface strain measurement allows the determination of the cohesive traction along with... [more]

For the high-salt reservoir of the Fengcheng Formation in the Mahu area, the production decreases rapidly due to the conductivity decrease after fracturing. The analysis shows that this has a great relationship with the special salt dissolution characteristics of the High salinity reservoir. In order to study the problem of salt dissolution pattern, the effect of different temperatures, the salt concentration of fracturing fluid, the viscosity of fracturing fluid, and injection rate on the rate of salt dissolution was evaluated by using the dynamic experimental evaluation method of salt dissolution. Through the grey correlation analysis of salt rock dissolution rate, it can be found that the degree of influence is from large to small which the influence of temperature is greater than fracturing fluid velocity, followed by fracturing fluid viscosity and, finally, fracturing fluid salt concentration. The results of compressive strength tests on salt-bearing rocks after dissolution show t... [more]

We report the design, fabrication, and testing of a humidity sensor based on an optical fiber-based evanescent wave probe. The fiber was bent into a U-shape and de-cladded at the location of the bending. The de-cladded section was coated either with Au or with ZnO nanoparticles. Humidity is detected based on the interaction in the surface plasmon resonance of the Au/ZnO nanoparticles excited by an evanescent wave of light passing through the optical fiber. The response of the U-bent fibers to humidity was investigated using a specifically designed low-voltage portable interrogation box. We found that the fibers coated with ZnO nanoparticles were able to detect a minimum 0.1% change in humidity with an average sensitivity of 143 µV/%RH and 95% linearity over the 10% to 80% humidity range. In comparison, samples coated with Au and Au + ZnO nanoparticles demonstrated a minimum change detection of 0.3% RH and 2% RH respectively. The response and recovery time of the sensor were measured to... [more]

The goal of this study was to evaluate the impact of simulating different fuel shapes for the material testing reactor (MTR). Two OpenMC codes were built, and the first OpenMC model was simulated using a curved shape fuel element to mimic the real dimensions and shape of the MTR. The code core parameters were validated with the collected parameters from the experimental work and two well-known Monte Carlo simulation codes (MCNP and SCALE). The validation process included the axial flux profile and criticality. After the OpenMC curve fuel model was validated, the MTR fuel was simulated as flat fuel elements with the exact amount of fuel as in the curve fuel model. By comparing the two OpenMC models’ calculations, it was observed that the radial flux distribution has only a slight difference due to fuel mass similarity. In conclusion, simulating the MTR fuel as flat elements provided a good agreement calculation compared to the real shape, but it was also observed that this might carry s... [more]

Currently, the integration method of silicon PIN radiation detectors faces challenges such as complex processes, poor reliability and thick dead layers. Novel integration methods based on metal bonding technology for realizing the integration of thick and thin PIN detectors are needed with the requirement of reducing signal crosstalk, package volume and weight. Combined with the current research on metal bonding technology, this paper presents an extensive review of metal bonding technology, especially metal Al bonding technology, to provide a certain reference to future research on the bonding processing of high-performance silicon PIN detector devices.

The development of the Mahu tight reservoir has adopted horizontal wells with staged fracturing. In the fracturing, there is a problem of a high fracturing pressure. Acid treatment is often used to lower the fracturing pressure on site. At present, the impact of this acid treatment on the physical parameters of the rocks of the reservoir in the Mahu region has not been systematically studied. Aiming to solve this problem, this paper conducted an experimental study on how acid dissolution affects the physical properties of the Mahu conglomerate, including its porosity, permeability, triaxial rock mechanical parameters, tensile strength, and mineral composition. First, the experimental scheme was designed. Next, a series of experiments were conducted. Finally, the experiment results were analyzed comparatively before and after acidizing. The acid composition, concentration, and contact time were the main factors for the analysis, based on which the acid system and related parameters were... [more]

In this study, the electronic structure of the galena surface was investigated using the first-principle calculation. The results of band structure, density of states, Mulliken population distribution, and frontier orbital analysis showed that galena was the p-type semiconductor of the direct band gap. During the formation of galena crystals, the 3p orbital of the S and the 6p orbital of the Pb played a primary role. Additionally, S atoms in galena quickly lose electrons and are oxidized, while Pb readily reacts with anions. The results of surface structure and electronic properties, such as surface relaxation, surface state energy levels, electronic density of states, and atomic charge distribution showed that the electronics in the 6p orbital of the Pb are transferred to the 3p orbital of the S in galena crystal. They caused the change of atomic valence states in lattice surfaces. The total electron number of the outermost surface layer was also higher than the bulk, giving the galen... [more]

The effects of different mineral admixtures on the evolution of static yield stress of common composite cementitious material paste and ultra-high-performance concrete (UHPC)-based paste were investigated. The results show that there are obvious differences in the role of mineral admixtures in the common paste and the UHPC-based paste. Adding mineral admixtures can change the initial static yield stress of the paste by affecting the particle size, particle shape and the charged particles. The addition of mineral admixtures with small particle size such as silica fume and ultrafine slag can increase the initial static yield stress of common paste but reduce that of UHPC-based paste. Adding mineral admixtures changes the evolution of static yield stress of the paste by affecting the particle spacing and the formation and growth rate of hydration products. In turn, the addition of ultrafine slag or silica fume increases the growth of the static yield stress of common paste. Adding slag, f... [more]

Wire and Arc Additive Manufacturing (WAAM) of Ti-6Al-4V is becoming increasingly important in the aerospace industry for the production of large parts. Due to the high welding requirements of the material, high quality demands are placed on the process. To meet these high demands, quality assurance measures are applied to maintain mechanical and geometrical part properties. First, the interlayer temperatures that are applied influence the final geometry. The part must meet geometric accuracies in order to be machined after the WAAM process. Second, Ti-6Al-4V materials have a high affinity to absorb oxygen from the environment at elevated temperatures. This oxygen uptake results in a discoloration of the surface and an embrittlement of the material. Therefore, a defined and monitored oxygen content in the build chamber is crucial. This work presents an approach to determine limitations for the interlayer temperature of the part and the oxygen content in the build chamber. The influence... [more]

Photoelectrocatalysis takes advantage of electrocatalytic and photocatalytic processes [...]

Modern antibiotics face many obstacles, starting with the ever-increasing resistance of microorganisms directed against the antibiotic. An important problem is also the existing trend of polypharmacy. The aim of this study was to develop qualitative and quantitative conditions for the determination of cefepime-hydrochloride solution individually and in mixtures containing other substances with biological activity, such as ketoprofen, gestodene with ethinylestradiol, estradiol, caffeine, calcium ions, paracetamol, bisoprolol, acetylsalicylic acid and ibuprofen, using thin-layer chromatography combined with densitometric analysis. The influence of temperature on the stability of cefepime in these situations was investigated. Furthermore, the effect of UV radiation on the stability of the antibiotic in model drug mixtures was tested. On the basis of the dependence of changes on the concentration of cefepime over time, the order of the reaction was designated, followed by the kinetic param... [more]

Domoic acid (DA) is a neurotoxin mainly produced by Pseudo-nitzschia diatom, which belongs to the genera Rhomboida. It can combine with the receptors of glutamate of neurotransmitters, then affecting the normal nerve signal transmission of the organism and causing nervous system disorders. However, as a natural marine drug, DA can also be used for pest prevention and control. Although the distribution of DA in the world has already been reported in the previous reviews, the time and location of its first discovery and the specific information are not complete. Therefore, the review systematically summarizes the first reported situation of DA in various countries (including species, discovery time, and collection location). Furthermore, we update and analyze the factors affecting DA production, including phytoplankton species, growth stages, bacteria, nutrient availability, trace metals, and so on. These factors may indirectly affect the growth environment or directly affect the physiol... [more]

The productivity prediction of gas wells in carbonate gas reservoirs is greatly affected by the characteristics of gas−water two-phase flow and fracture seepage parameters. Compared with numerical simulation, the productivity prediction based on the analytical model is fast and widely used, but the traditional analytical model is fairly simplified while dealing with the nonlinear problem of the two-phase seepage equation, leading to a large discrepancy in the results of dynamic analysis. To solve this problem, this paper considers the characteristics of gas−water two-phase flow in the reservoir and fracture, uses the dual-medium model to characterize the stress sensitivity of the fracture and reservoir, and establishes a gas−water two-phase productivity prediction model for carbonate gas reservoirs. Combining the flowing material balance equation with the Newton iteration method, the nonlinear parameters of the percolation model are updated step by step with the use of average formatio... [more]

Adsorption kinetics of As and Pb onto composite beads synthesized with stone powder, chitosan, and maghemite (SCM beads) with weight ratio of 1:1:0.5 were investigated in batch mode. Several kinetic models such as pseudo-first order kinetic model (PFOKM), pseudo-second order kinetic model (PSOKM), two compartment first order kinetic model (TCFOKM), and modified two compartment first order kinetic model (MTCFOKM) were utilized to analyze the kinetics. Although the beads had low specific surface area and pore volume, MTCFOKM, one of two compartment models, could predict the most accurately because the As and Pb were adsorbed onto at least two kinds of adsorption sites such as functional groups in chitosan and Fe in maghemite. In MTCFOKM, both the fast adsorption fraction (f1’) and the fast adsorption constant (k1’) for Pb were higher than those for As. Therefore, the equilibrium time (teq) for Pb adsorption was shorter than that for As adsorption, indicating that Pb adsorption was more a... [more]

Successful progress in industrial development requires the use of cost-effective materials and advanced innovative materials with improved properties [...]

A sustainable separation concept for large-scale recycling of NdFeB magnets under atmospheric pressure was developed by utilizing a combination of two separation concepts known from the literature: (I) selective pre-separation by in situ chlorination and evaporation of ground oxidized NdFeB material and (II) subsequent distillation for high-purity recovery of all recyclable chlorinated material components, especially its Rare Earth Elements (REEs). Theoretically, simplified estimations of the time conversion curves at 1173 K, 1273 K, and 2000 K of a single particle resulted in the idea of realizing chlorination in some kind of combustion chamber, fluidized bed, or continuous combustion chamber. After chlorination, all non-volatile components, such as REE chlorides, are condensed out of the vapor phase in a single-stage phase separator. For subsequent fine separation by distillation (1292−1982 K for Rare Earth Chlorides and 418−867 K at 2500 kPa for boron and zirconium chloride recovery... [more]

To accurately evaluate the shale oil resources in the Funing Formation of the Gaoyou Sag, Subei Basin, light and heavy hydrocarbon correction models of S1 were developed based on the rock pyrolysis of liquefrozen, conventional, and oil-washed shales. The improved ΔlogR technique was applied to establish the TOC, S1, and S2 logging evaluation methods. The results showed that the S2 values after oil washing were significantly lower than before. The difference between these two S2 (ΔS2) values is the heavy hydrocarbon correction amount of S1, which is about 0.69 S2. There was almost no loss of light hydrocarbons during liquefrozen shales’ pyrolysis tests; the ratio of liquefrozen to conventional S1 values is the light hydrocarbon correction factor, which is about 1.67. The corrected S1 is about 3.2 times greater than the conventional shale-tested value. The S1 and TOC are obviously “trichotomous”; a TOC greater than 1.5% and corrected S1 larger than 4.0 mg/g corresponds to the enriched re... [more]

In the fishmeal industry, seawater is used to transport fish to the factories. Due to this, “pumping water” with high concentrations of organic matter is generated that is treated via chemical coagulation before letting it into the sea. The objective of this study is to characterize and compare the sludge obtained from conventional chemical coagulation and the sludge from the electrocoagulation process. A pilot electrocoagulation plant was built next to a chemical coagulation plant. The sludge obtained from both methodologies was analyzed for its proximal composition, its iron and aluminum content, and the fatty acid profile in its contained fat. Electrocoagulation was found to produce sludge with a higher concentration of lipids and ash, which indirectly confirmed that it removes more organic pollutants and salts than chemical coagulation. The contents of aluminum and iron in the sludge obtained by electrocoagulation were 4.2% and 0.025%, respectively, while those in the sludge obtain... [more]

In the original publication, there was a mistake in Figure 6 [...]

This research aims to provide insights into the biological efficacy of a newly formed hydrophobic deep eutectic solvent (DES). A DES based on menthol was successfully synthesized with fatty acids. The DESs’ properties as enzyme activators were examined against a neat counterpart. The menthol:decanoic acid (1:1) combination showed improved thermal stability, strong catalytic activity, and reusability for up to four subsequent cycles under ideal conditions (pH 7.0, 40 °C for 2 h). The hydrophobic DES replaced hexane in ester synthesis, where RNL@DES5 showed better fatty acid conversion compared to neat RNL. This study demonstrated promising applications of hydrophobic DESs in non-aqueous organic reactions.

RTA (Rate Transient Analysis) is a valuable method for obtaining reservoir parameters and well performance, but current RTA models hardly consider the MLVF (Multi-Layer Vertical Fractured) well in a layered tight gas reservoir. To capture the production response caused by the fracture with non-uniform length and conductivity, a novel RTA model for an MLVF well in a layered tight reservoir was presented. In this paper, we present a novel tight gas reservoir RTA model, an extended MLVF well with non-uniform fracture length and conductivity to investigate the production decline feature by the combined RTA type curves. After that, the proposed RTA model is verified to ensure calculation accuracy. Sensitivity analysis is conducted on the crucial parameters, including the formation transmissibility, formation storability, fracture length, fracture conductivity, and fracture extension. Research results show that there are three rate decline stages caused by a multi fracture with non-uniform c... [more]

Power cable condition diagnosis and deterioration location rely on signatures of aging characteristics which precede the final breakdown. The purpose of this study was to investigate how to diagnose and locate the aging and/or deterioration of power cables through the analysis of the impedance spectroscopy. The concepts of the reference frequency and characteristic frequency of cable impedance spectroscopy are defined for the first time. Based on the reference frequency, the optimal frequency range for analysis of impedance spectroscopy can be determined, whilst based on characteristic frequency, a set of criteria for assessing cable conditions are examined and established. The solution proposed in this paper has the advantage of being easier to implement than the previously reported “broadband” impedance spectroscopy methods, as it helps to reduce the frequency range for measurement instrumentations; the proposed method also does not need the measurements of the parameters of the cabl... [more]