In this paper, five groups of industrial aluminium back-surface-field (Al-BSF) solar cells were made from silicon wafers from different locations of a B-doped Czochralski silicon ingot. Then, we performed the first LID (45 °C, 1 sun, 12 h), regeneration (100 °C, 1 sun, 24 h), and second LID (45 °C, 1 sun, 12 h) treatments on the cells, and measured the in-situ changes of their I-V characteristic parameters by using an I-V tester during the experiment. The cells were also characterized by Suns-Voc measurement, full-area light beam induced current scanning, and external quantum efficiency measurement at the four breakpoints of treatments (before and after the first LID, after regeneration and the second LID). It was found that the LID and regeneration of the Al-BSF solar cells can be explained by the LID and regeneration reaction of B-O defects and the LID caused by dissociation of Fe-B pairs. After regeneration, the relative decay rate of efficiency decreased from 2.75−3.8% during the f... [more]

This article presents the results of a systematic study on the composition and origin of PM1-2 microspheres in high-calcium fly ash. The composition of individual microspheres was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. It is shown that the compositions of the analyzed microspheres satisfy the general dependency with a high correlation coefficient: [SiO2 + Al2O3] = 88.80 − 1.02 [CaO + Fe2O3 + MgO], r = −0.97. The formation pathway is parallel to the general trend: anorthite, gehlenite, esseneite, tricalcium aluminate, ferrigehlenite, and brownmillerite. The microspheres were classified into four groups depending on the content of major components: Group 1 (CaO > 40, SiO2 + Al2O3 ≤ 35, Fe2O3 < 23, MgO < 16 wt %); Group 2 (30 < CaO < 40, SiO2 + Al2O3 ≤ 40, Fe2O3 < 27, MgO < 21 wt %); Group 3 (CaO ≤ 30, 40 ≤ SiO2 + Al2O3 ≤ 75, Fe2O3 < 10, MgO < 10 wt %); and Group 4 (14 < CaO < 40, SiO2 + Al2O3 < 14, Fe2O3 > 30, MgO ≤... [more]

In a recent advance, zirconium triselenide (ZrSe3) nanosheets with anisotropic and strain-tunable excitonic response were experimentally fabricated. Motivated by the aforementioned progress, we conduct first-principle calculations to explore the structural, dynamic, Raman response, electronic, single-layer exfoliation energies, and mechanical features of the ZrX3 (X = S, Se, Te) monolayers. Acquired phonon dispersion relations reveal the dynamical stability of the ZrX3 (X = S, Se, Te) monolayers. In order to isolate single-layer crystals from bulk counterparts, exfoliation energies of 0.32, 0.37, and 0.4 J/m2 are predicted for the isolation of ZrS3, ZrSe3, and ZrTe3 monolayers, which are comparable to those of graphene. ZrS3 and ZrSe3 monolayers are found to be indirect gap semiconductors, with HSE06 band gaps of 1.93 and 1.01 eV, whereas the ZrTe3 monolayer yields a metallic character. It is shown that the ZrX3 nanosheets are relatively strong, but with highly anisotropic mechanical r... [more]

Establishing a suitable classification and evaluation scheme is crucial for sweet spot prediction and efficient development of shale oil in the Chang 71-2 sub-member of the Longdong area. In this paper, a series of experiments, such as casting thin sections (CTS), scanning electron microscopy (SEM), low-temperature nitrogen adsorption (LTNA), high-pressure mercury intrusion porosimetry (HMIP), and nuclear magnetic resonance (NMR), were integrated to classify the pore throats and shale oil reservoirs in the study area. Moreover, the pore structure characteristics of different types of reservoirs and their contributions to productivity were revealed. The results show that the pore-throat system can be divided into four parts: large pore throats (>0.2 μm), medium pore throats (0.08~0.2 μm), small pore throats (0.03~0.08 μm), and micropore throats ( 0.1 mD), type II (Φ ≥ 8%, 0.05 mD < K < 0.1 mD), type III (Φ ≥ 5%, 0.02 mD < K < 0.05 mD) and type IV (Φ < 5% or K < 0.02 mD... [more]

At present, there has been no mechanized equipment designed for the separation of the leaves from the stems of wakame in China, and the stem−leaf separation is mainly completed by manual work, which suffers from problems such as low efficiency, high cost, and poor quality. To develop mechanized stem−leaf separation equipment of wakame, it is necessary to have a preliminary understanding of the biomechanical characteristics of wakame. In this study, we adopted an electronic universal testing machine, a texture tester, and a friction tester to investigate the mechanical characteristics of the stems and leaves of salted wakame. Analysis was performed to clarify the effects of salted wakame thickness and loading speed on the tension, compression, shear, and separation mechanical properties as well as the effects of the loading speed, normal force, and contact material on the friction characteristics. As shown in the results, the average tensile strength, shear strength, and resilience of s... [more]

The sulfide stress cracking (SSC) behavior of three micro-alloying 110 ksi grade Cr-Mo casing steels were evaluated according to the A-Method tensile test specified in the NACE TM0177 standard (NACE A-method). The fractures of SSC specimens and the micro-structures of the casing steels were characterized by scanning electron microscopy (SEM) with electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM) in the BF and STEM mode. The results show that on the premise of 110 ksi, the yield strength of Co-Mo steel was satisfactory, finer spherical carbides increased the number of irreversible traps; widened polygonised martensitic laths, lowered dislocation density, and lowered the proportion of high-angle grain boundaries and the Σ3 boundaries decreased hydrogen permeability and diffusivity. The SSC resistance of Co-Mo steel with above micro structure characteristics was enhanced.

Settlement of the pile ends in end-bearing rigid pile composite foundations is generally minimal, so only relying on the cushion to coordinate the pile soil deformation may result in insufficient deformation adjustment capacity. Using a deformation adjustor with a specific stiffness on the top of the pile is a method to coordinate pile−soil deformation, and the stiffness value of the deformation adjustor depends on the accurate calculation of soil deformation; however, the calculation of soil deformation is not mature at present. A new deformation adjustor based on strengths used in composite foundations is proposed, in which foam slabs with different yield strengths are placed on the top of the pile to coordinate the pile−soil deformation. Five tests are used to study the mechanical and deformation properties of a composite foundation with a foam slab. The test results show that when the stress at the top of the pile is less than the yield strength of the foam slab, the coordination o... [more]

The strength aspect of clay soil is a critical concern in practical engineering design. Electroosmosis (EO) has been adopted as a foundation treatment technology in some projects to increase the strength of soft clay. In order to widen the understanding on shear strength performance of EO-treated soil, the behavior of EO-treated soft clay using electrokinetic geosynthetics (EKG) as electrodes under the effect of water immersion was evaluated and compared with that of vacuum preloading (VP) treated soft clay under similar conditions. The main finding was that the EO-treated soil when immersed in water offered more resistance to the change in average water content than VP-treated soil. The average shear strength of EO-treated soil fell by 36.6% during 4 extra days of immersion. When the immersion time was extended to 10 days, the average shear strength fell by 65.4%. In contrast, the immersion time had little influence on the shear strength of VP-treated soil. Hence, if EO-treated soft c... [more]

In this study, a series of g-C3N4 nanosheets were prepared by various thermal oxidative etching times from four different precursors (urea, melamine, dicyandiamide and thiourea). The physicochemical properties of these g-C3N4 nanosheets were analyzed in detail using scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence emission spectra, Fourier transform infrared spectroscopy (FTIR), Brunauer−Emmett−Teller (BET) analysis and ultraviolet-visible diffuse reflectance. The results revealed that the g-C3N4 nanosheets obtained a thinner layer thickness and larger specific surface area, with an extension of thermal oxidative etching time. Meanwhile, sulfamethazine (SMZ), one of the most widely used sulfonamides, was used to evaluate the photocatalyst activity of the g-C3N4 nanosheets prepared in this study. Compared to other g-C3N4 nanosheets, urea-derived g-C3N4 nanosheets under 330 min thermal oxidative etching showed the highest photocatalytic activity for SMZ unde... [more]

Because of their high nutritional value, the demand for scallops is increasing year by year. In the process of improving people’s living standards, the ready-to-eat characteristics and dry sales characteristics of this product make its shelling process particularly important in the production process. However, the mechanism of ultra-high pressure shelling has not yet been clarified. Therefore, in-depth study of the structural change of the scallop connection interface is of vital importance to explore the mechanism of ultra-high pressure shelling and the development of intelligent equipment from the mechanical point of view. The obturator muscle fibers and the inner surface materials of the shell at the obturator muscle scar of the scallop at 100, 200 and 300 MPa were obtained for Raman spectrum, Fourier-transform infrared spectrum and scanning electron microscopy analysis. The results showed that under the pressure of 200 MPa, the degree of protein denaturation of scallop adductor mus... [more]

The increasingly intense consumption of plastics and, above all, their improper disposal in the environment are causing serious environmental concerns. Great efforts have been made for the development of new methods aimed at facilitating and speeding up the identification and sorting of different materials in the plastic recycling process. In this field, new strategies based on fluorescent tagging have been developed. This work concerns the synthesis and characterization of new fluorescent copolymers of polyethylene (PE) and polystyrene (PS), which are among the most produced and consumed plastic materials. The synthesized copolymers are potentially suitable for use as fluorescent markers of PE and PS. Ethylene-co-N-pentenyl carbazole (P(E-co-PK)) and styrene-co-4-(N-carbazolyl)methyl styrene (P(S-co-SK)) copolymers were prepared by Ziegler−Natta and free radical polymerization, respectively. If excited at 300 nm, both P(E-co-PK)s and P(S-co-SK)s give fluorescence emissions resulting i... [more]

The application of adhesively bonded joints in aerospace structural parts has increased significantly in recent years and the general advantages of their use are well-documented. One of the disadvantages of adhesive bonding is the relevant permanence, when compared to traditional mechanical fastening. End-of-life processes generally require the separation of the adherents for repair or recycling, and usually to achieve this, they combine large mechanical forces with a high temperature, thus damaging the adherents, while consuming large amounts of energy. In this work, a novel disassembly technique based on laser-induced shock waves is proposed for the disassembly of multi-material adhesively bonded structures. The laser shock technique can generate high tensile stresses that are able to break a joint, while being localized enough to avoid damaging the involved adherents. The process is applied to specimens made from a 3D-woven CFRP core bonded to a thin Ti layer, which is a common asse... [more]

Remarkable developments have been achieved in recent decades in terms of the utilization of isolated enzymes as green alternative catalysts in polymer science [...]

(1) Background: In this study, the potential use of Dioscorea rotundata hydrocolloids was evaluated to develop low-fat mayonnaise. (2) Methods: The effect of different concentrations of hydrocolloids on the physicochemical, microstructural, and rheological properties of mayonnaise was evaluated. (3) Results: Physicochemical analyses showed pH values that were stable over time but decreased with increasing hydrocolloid concentration. The color parameters showed a decrease in luminosity and an increase in the values of a* and b* over time, which can be translated into an increase in yellow and a decrease in white, with a greater accentuation in the control sample. The rheological study allowed us to obtain a non-Newtonian flow behavior of the shear-thinning type for all samples, and the flow curves were well-fitted by the Sisko model (R2 ≥ 0.99). The samples had an elastic rather than viscous behavior, typical of dressings and emulsions. This indicates that the storage modulus was greate... [more]

Cellulose acetate (CA) is a semisynthetic, biodegradable polymer. Due to its characteristics, CA has several applications, including water membranes, filament-forming matrices, biomedical nanocomposites, household tools, and photographic films. This review deals with topics related to the CA membranes, which are prepared using different techniques, such as the phase inversion technique. CA membranes are considered very important since they can be used as microfiltration membranes (MF), ultrafiltration membranes (UF), nanofiltration membranes (NF), reverse osmosis (RO) membranes, and forward osmosis (FO) membranes. Membrane fouling results from the accumulation of materials that the membrane rejects on the surface or in the membrane’s pores, lowering the membrane’s flux and rejection rates. There are various forms of CA membrane fouling, for instance, organic, inorganic, particulate fouling, and biofouling. In this review, strategies used for CA membrane antifouling are discussed and su... [more]

Recent research papers have confirmed the prevalence of microorganisms resistant to numerous antimicrobial agents, leading to spreading infections, extended hospitalizations, and increased mortality rates. The amplifying factors stimulate the need to discover new molecules able to cut off the developing resistance of pathogens against medicines. The current study presents a molecular docking procedure applied on 15 new pyridine−thiourea derivatives in order to test their activities against S. aureus and E. coli. The protein crystal structures were obtained from the Protein Data Bank (PDB). Processes such as geometry optimization, molecular properties (log P, polarizability, E HOMO, E LUMO, area and volume of the molecules, and ovality), drug-likeness, pharmacokinetic and pharmacogenomic profiles, and molecular docking studies are discussed in the present research. The approach involved the determination of the molecular properties for each chemical structure by using the Spartan 14 sof... [more]

Despite the globally increasing use of platinum-based cytostatic drugs in the treatment of several types of cancer, only limited attention has been paid to developing a treatment for contaminated liquid samples originating from hospitals, laboratories and manufacturing facilities before and after their administration. In this work, we assess the efficiency of a low-cost adsorbent material, a dithiocarbamate-functionalized silica, in removing cisplatin from a solution containing it in the 0.5−150 mg L−1 concentration range. The advantage of having a surface-functionalized silica is that adsorption can occur by either non-covalent interaction or surface complexation. In the latter case platinum(II) is de-complexed and the original drug is no longer present. Adsorption occurs through a first rapid step, followed by a second slower process. This is likely due to the fact that in our operating conditions (0.9% w/v NaCl), only the original compound is present, for which ligand substitution i... [more]

The high-temperature sintering of CaO-based materials leads to the serious decay of energy storage performance during the calcination/carbonation cycle. To overcome the loss in porosity problem, an efficient CaO-based material for thermal energy storage was synthesized using bamboo fiber as the biotemplate. The synthesis parameters (bamboo fiber addition, pyrolysis, Al2O3 loading) and the energy storage reaction characteristics of CaO-based energy storage material were optimized on the basis of cyclic calcination/carbonation experiments. The results show that the sacrificed biotemplate enhances the porosity of the synthetic material, denoting improved energy storage density. The cumulative energy storage density of the templated material over 50 cycles is 24,131.44 kJ/kg higher than that of limestone. The carbonation conversion and energy storage density of the templated CaO-based material doped with 5 wt.% Al2O3 and 0.5 g bamboo fiber reach 0.75 mol/mol and 2368.82 kJ/kg after 10 cycl... [more]

A significant issue for the ecosystem is the presence of boron in water resources, particularly in produced water. Batch and dynamic experiments were used in this research to extract boron in the form of boric acid from aqueous solutions using boron selective resins, DIAION CRB05. DIAION™ CRB05 is an adsorbent that is effective in extracting boron from aqueous solutions due to its high binding capacity and selectivity for boron ions, and it is also regenerable, making it cost-effective and sustainable. Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), and FTIR analysis for DIAION CRB05 characterization. To increase the adsorption capacity and find the ideal values for predictor variables such as pH, adsorbent dose, time, and boric acid concentration, the Box−Behnken response surface method (RSM) was applied. The dosage was reported to be 2000 mg/L at pH 2 and boron initial concentration of 1115 mg/L with 255 min for the highest removal anticipated from RSM.... [more]

Material treatment in pulsation reactors (PR) brings the possibility of synthesizing powdery products with advantageous properties, such as nanoparticle sizes and high specific surface areas, at an industrial scale. The extraordinary material properties can be ascribed to special process parameters in a PR, primarily the periodically varying conditions and the consequently enhanced heat and mass transfer between the medium and the particles of the material. Understanding the connections between the PR operation parameters, such as fuel and air intake or PR geometry, and the resulting process parameters (temperature distribution, flow velocity and pressure field, and frequency of the pulsations) is essential to enabling a controllable treatment process. Despite the long history of pulsation reactor technology, many connections and dependencies remain unclear. Thus, the influence of the fuel (and air) supply on the pulsation reactor behavior is experimentally examined in this study. The... [more]

The effects of the adhesive thickness and overlap of a polyurethane adhesive have been studied by using different substrate configurations. Single lap joint (SLJ) specimens have been tested with homologous substrates, carbon fibre-reinforced plastics and painted metal substrates. Furthermore, a configuration with dissimilar substrates has been included in the experimental campaign. Both types of these adhesive and substrates are used in the automotive industry. The bonding procedure has been carried out without a surface treatment in order to quantify the shear strength and stiffness when surface treatments are not used on the substrates, reproducing typical mass production conditions. Three different ageing cycles have been used to evaluate the effects on SLJ specimens. A finite element model that uses cohesive modelling has been built and optimised to assess the differences between the different adopted SLJ configurations.

Trichlorosilane (SiHCl3) is an important raw material for preparing solar cells and semiconductor chips in the Siemens method. Since the boiling points of SiHCl3 and methyldichlorosilane (CH3SiHCl2) are close to each other, it is difficult to remove CH3SiHCl2 from the raw material to obtain high-purity products by traditional distillation methods. Therefore, we propose an efficient catalytic approach to convert CH3SiHCl2 to methyltrichlorosilane (CH3SiCl3) with an anion-exchange resin as the catalyst and tetrachlorosilane (SiCl4) as the Cl donor in a continuous-flow fixed bed reactor. Seven anion-exchange resins, including D201, D301, D303, 201 × 7, D301F, D315 and D380 were evaluated. The results showed that D301 resin had the best performance. Reaction conditions such as reaction temperature, reactant molar ratio and catalyst stability were investigated. The maximum conversion of CH3SiHCl2 was 60% at an optimum reaction temperature of 150 °C, n(CH3SiHCl2):n(SiCl4) = 1:3 and a liquid... [more]

Autoclaved aerated concrete is an excellent thermal insulation wall material, but with a large amount of waste. This paper describes the high-temperature activation and rehydration activity of waste cement−lime−sand autoclaved aerated concrete (SAAC) and discusses the high-temperature phase transition of SAAC. SAAC calcined at 750 °C was confirmed to be a metastable and amorphous state, which could hydrolyze Ca2+ ions with reactivity in water. The conductivity curve demonstrates that the concentration of ions in the suspension decreases rapidly at 150−250 min, and the hydration reaction turns dominant at this time. The hydration heat curve also displays a hydration exothermic peak at 2.5 h. In addition, the conductivity measurement of suspension and the exothermic measurement of hydration reaction proves that SAAC calcined at 750 °C has a hydration activity and can rehydrate with SiO2 in the system. The rehydration activity was verified by replacing 30% cement in the standard test bloc... [more]

Forty-eight crude oils with variations in specific gravity (0.782 ≤ SG ≤ 1.002), sulphur content (0.03 ≤ S ≤ 5.6 wt.%), saturate content (23.5 ≤ Sat. ≤ 92.9 wt.%), asphaltene content (0.1 ≤ As ≤ 22.2 wt.%), and vacuum residue content (1.4 ≤ VR ≤ 60.7 wt.%) were characterized with HTSD, TBP, and SARA analyses. A modified SARA analysis of petroleum that allows for the attainment of a mass balance ≥97 wt.% for light crude oils was proposed, a procedure for the simulation of petroleum TBP curves from HTSD data using nonlinear regression and Riazi’s distribution model was developed, and a new correlation to predict petroleum saturate content from specific gravity and pour point with an average absolute deviation of 2.5 wt.%, maximum absolute deviation of 6.6 wt.%, and bias of 0.01 wt.% was developed. Intercriteria analysis was employed to evaluate the presence of statistically meaningful relations between the different petroleum properties and to evaluate the extent of similarity between th... [more]

Uranium aerosols are released from uranium-containing materials in high-temperature environments caused by nuclear accidents or other processes. Research on the generation characteristics of uranium aerosols under such conditions is an important part of nuclear-safety analysis. In this experiment, the similarity between metal cerium aerosols and uranium material aerosols was evaluated from the aspects of particle size distribution and source term. Combined with the experiment data, the effect of air flow rate and sampling time is discussed. The calculation result of the air release fraction (ARF) is 6.07 × 10−3−4.8 × 10−2, and the respirable fraction (RF) is 0.810−0.978, respectively, showing that the size distribution of particles and ARF of the cerium aerosol are different from the results of the uranium aerosols in the literature, while the RF is similar to the results obtained by using the uranium−niobium alloy in the literature.