Hasil untuk "Chemical engineering"

Ning Zhang, Xi-Yue Li, Huacheng Ye et al.

G. Froment, K. Bischoff

Md Imran Hasan, Gang Lei, Dylan Lu et al.

Electric vehicle (EV) adoption is generating a rapidly increasing stream of retired lithium-ion batteries for second-life deployment. However, thermal safety concerns continue to limit their reuse. This paper reviews second-life battery (SLB) thermal safety and management and organizes existing work through a mechanism-to-deployment framework linking four domains: degradation mechanisms, cell screening, pack configuration, and monitoring. Evidence indicates that thermal risk depends on the degradation pathway rather than capacity fade. In fact, cells with comparable capacity can exhibit substantially different trigger temperatures depending on whether lithium plating or solid-electrolyte interphase (SEI) growth dominates. Therefore, capacity-based screening is insufficient because cells that satisfy capacity thresholds may still remain thermally unstable. The four domains are tightly coupled: the degradation pathway determines screening requirements; screening outcomes constrain pack design; pack topology influences fault escalation; and together these factors determine what monitoring can reliably detect. This review highlights three gaps and outlines future research directions in the field of SLB thermal safety and management: limited aged-cell thermal characterization by degradation pathway, insufficient diagnostic validation under industrial-throughput conditions, and the incomplete translation of screening outputs into design rules.

Shuxin Li, Wenfei Shen, Shuhan Guo et al.

Considered a pivotal advancement for commercial applications, blade coating technology for large area photovoltaic devices has emerged as a forefront research area in the field of polymer solar cells (PSCs). Herein, a high-performance PM6:L8-BO device is fabricated with the blade-coating method in ambient air. Meanwhile, Eu3+-induced diblock polymer aggregates (EIPAs) and Tb3+-induced diblock polymer aggregates (TIPAs) with excellent fluorescent properties were synthesized through self-assembly and incorporated as an additive into the PM6:L8-BO system to increase the ultraviolet light absorption and enhance BC-PSC light harvesting. By employing this strategy, the blade-coating device's power conversion efficiency (PCE) was improved from 12.25 % to 13.63 %, and the relative efficiency was enhanced by 11.3 %. In addition to the performance improvement, the stability of the devices was also enhanced by 19 %, indicating the effectiveness of this approach in producing more efficient and durable PSCs.

Guanzhou Di, Chen Lu, Mengting Xue et al.

ObjectivesRetinal pigment epithelium (RPE) cell transplantation holds therapeutic promise for retinal degenerative diseases, but longitudinal monitoring of graft survival and efficacy remains clinically challenging. The aim of this study is to develop a simple and effective method for the therapeutic quantification of RPE cell transplantation and immune rejection in vivo.MethodsA nanoprobe was developed and modified to label donor RPE cells, and used to monitor the position and intensity of the fluorescence signal in vivo. Immunofluorescence staining and single-cell RNA sequencing (scRNA-seq) were used to characterize the cell types showing the fluorescence signal of the nanoprobe and to determine the composition of the immune microenvironment associated with subretinal transplantation.ResultsThe spatial distribution of the fluorescence signal of the nanoprobe corresponded with the site of transplantation, but the signal intensity decreased over time, while the signal distribution extended to the choroid. Additionally, the nanoprobe fluorescence signal was detected in the liver and spleen during long-term monitoring. Conversely, in mice administered the immunosuppressive drug cyclosporine A, the decrease in signal intensity was slower and the expansion of the signal distribution was less pronounced. Immunofluorescence analysis revealed a significant temporal increase in the proportion of macrophages with nanoprobe-labeled cells following transplantation. The stability and cell-penetrating ability of the nanoprobe enables the labeling of immune cell niches in RPE transplantation. Additionally, scRNA-seq analysis of nanoprobe-labeled cells identified MDK and ANXA1 signaling pathway in donor RPE cells as initiators of the immune rejection cascade, which were further amplified by macrophage-mediated pro-inflammatory signaling.ConclusionNear-infrared fluorescent nanoprobes represent a reliable method for in vivo tracing of donor RPE cells and long-term observation of nanoprobe distribution can be used to evaluate the degree of immune rejection. Molecular analysis of nanoprobe-labeled cells facilitates the characterization of the dynamic immune cell rejection niche and the landscape of donor-host interactions in RPE transplantation.

Fetcia Jackulin, P. Senthil Kumar, Gayathri Rangasamy

Among the azo dye, Tartrazine is widely used for most of applications like pharmaceuticals, cosmetics, food, etc. As the demand for dye application is increased, the disposal of dye is also increasing. However it is very difficult to cleave due to its stability. Different methods are available, but the Advanced Oxidation Process (AOP) is an emerging technique used for treating various contaminants. In this study, sulfate radical (SO4−.) based AOP was performed to degrade tartrazine dye using iron oxide (Fe3O4) nanoparticles (NP). This NP was synthesized using the co-precipitation method, analyzed by X-Ray Diffraction (XRD), revealed the crystalline structure of the material and the average size of the particle was 16.17 nm also High Resolution- Scanning Electron Microscope (HR-SEM) showed spherical and cube shape of the particles with agglomeration. Response surface methodology (RSM) was carried out to determine the optimum condition based on central composite design. The optimum conditions were found to be pH-5.34, time- 113.58 min, NP- 0.89 g, SPS- 15.40 mM, and predicted degradation efficiency - 97.22% which was correlated to the experimental value- 96.66% with minimal error. Application of SO4−. radical implied an efficient degradation due to the involvement of both SO4−. and hydroxyl (OH-.) radical. Excess formation of SO4−. radicals, Fe2+ was majorily responsible for suppressive degradation. The intermediate compound was identified from Gas Chromatography-Mass Spectrometry (GC-MS), proved the absence of parent dye and occurrence of degradation due to Fe3O4/PS system.

Shuai Zhang, Tao Wang, Zhipeng Jiang

The contradiction between strength and electrical conductivity of pure aluminum (Al) hinders its wide applications in electrical engineering. In this study, an attempt was made to overcome this limitation by adding carbon nanotubes (CNTs) into Al matrix using friction stir processing (FSP) method. The results showed that CNTs were singly distributed in Al matrix and strong bonded CNTs/Al interfaces without chemical reaction as well as impurity contamination were formed. Interestingly, it was found that the axis of CNTs tended to be parallel to Al (111) planes, which provided a geometric basis for the formation of semi-coherent CNTs/Al interfaces. These semi-coherent CNTs/Al interfaces possessed an extremely low electrical resistivity, which weakened the total electron scattering generated by all CNT/Al interfaces. Meanwhile, strong bonded CNTs/Al interfaces effectively hindered dislocations movement, inducing an improvement of 84 % and 50 % in yield strength and tensile strength of Al respectively. As a result, the strength of Al was significantly improved without losing its electrical conductivity. This study provides a new strategy for breaking through the contradiction between strength and electrical conductivity of Al and then producing CNTs/Al nanocomposites with high strength and high electrical conductivity.

Jingyu Zhao, Hanqi Ming, Tao Guo et al.

Abstract Temperature variation and gas generation at different depths and positions in the coal combustion process were studied to determine the propagation and evolution of high temperature regions in the process of coal spontaneous combustion. This study selected coal samples from Mengcun, Shaanxi Province, People’s Republic of China, and developed a semi-enclosed experimental system (furnace) for simulating coal combustion. The thermal mass loss of coal samples under various heating rates (5, 10, and 15 °C/min) was analyzed through thermogravimetric analysis, and the dynamic characteristics of the coal samples were analyzed; the reliability of the semi-enclosed experimental system was verified through the equal proportional method of fuzzy response. The results reveal that the high-temperature zone is distributed nonlinearly from the middle to the front end of the furnace, and the temperatures of points in this zone decreased gradually as the layer depth increased. The apparent activation energy of the coal samples during combustion first increased and then decreased as the conversion degree increased. Furthermore, the proportion of mass loss and the mass loss rate in the coal samples observed in the thermogravimetric experiment is consistent with that observed in the first and second stages of the experiment conducted using the semi-enclosed system. The research findings can provide a theoretical basis for the prevention and control of high-temperature zones in coal combustion.

Tengfei Wang, Danning Zheng, Beibei An et al.

Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure (0.1 MPa) without any solvent and co-catalyst leading to 96.1% product yield. It can be reused five times to keep the product yield over 90%. These intriguing results are attributed to a new reaction mechanism, which is supported by theoretical calculations along with the measurements of 13C NMR spectrum and Fourier transform infrared spectroscopy (FT-IR). The excellent catalytic activity can be traced to a CO2-philic group along with an electrophilic hydrogen atom. Our work shows that incorporation of CO2-philic group is an feasible pathway to develop the new efficient ionic liquids.

Xiuqiong Chen, Qingmei Zhu, Zhengyue Li et al.

On account of the rigid structure of alginate chains, the oxidation-reductive amination reaction was performed to synthesize the reductive amination of oxidized alginate derivative (RAOA) that was systematically characterized for the development of pharmaceutical formulations. The molecular structure and self-assembly behavior of the resultant RAOA was evaluated by an FT-IR spectrometer, a ¹H NMR spectrometer, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), a fluorescence spectrophotometer, rheology, a transmission electron microscope (TEM) and dynamic light scattering (DLS). In addition, the loading and in vitro release of ibuprofen for the RAOA microcapsules prepared by the high-speed shearing method, and the cytotoxicity of the RAOA microcapsules against the murine macrophage RAW264.7 cell were also studied. The experimental results indicated that the hydrophobic octylamine was successfully grafted onto the alginate backbone through the oxidation-reductive amination reaction, which destroyed the intramolecular hydrogen bond of the raw sodium alginate (SA), thereby enhancing its molecular flexibility to achieve the self-assembly performance of RAOA. Consequently, the synthesized RAOA displayed good amphiphilic properties with a critical aggregation concentration (CAC) of 0.43 g/L in NaCl solution, which was significantly lower than that of SA, and formed regular self-assembled micelles with an average hydrodynamic diameter of 277 nm (PDI = 0.19) and a zeta potential of about −69.8 mV. Meanwhile, the drug-loaded RAOA microcapsules had a relatively high encapsulation efficiency (EE) of 87.6 % and good sustained-release properties in comparison to the drug-loaded SA aggregates, indicating the good affinity of RAOA to hydrophobic ibuprofen. The swelling and degradation of RAOA microcapsules and the diffusion of the loaded drug jointly controlled the release rate of ibuprofen. Moreover, it also displayed low cytotoxicity against the RAW264.7 cell, similar to the SA aggregates. In view of the excellent advantages of RAOA, it is expected to become the ideal candidate for hydrophobic drug delivery in the biomedical field.

Xiao-qiang Cao, Fei Xiao, Xiao-yu Xie et al.

Functional magnetic Fe3O4@PPy microspheres were prepared and characterized by XRD, FTIR, SEM, TEM, and magnetometer, and the adsorption of Hg(II) onto Fe3O4@PPy was investigated. The results showed that the adsorption of Hg(II) onto Fe3O4@PPy dramatically increases within 5 min and reaches adsorption equilibrium at 200 min. The adsorption of Hg(II) increases with pH increased, and a removal efficiency (RE) of 90.5% was obtained at pH 7.2. The isotherm studies revealed that the adsorption of Hg(II) onto the Fe3O4@PPy fits well with the Langmuir isotherm model, and the calculated qm value of 232.56 mg/g. The adsorption process of Hg(II) onto the Fe3O4@PPy is well-fitted by the pseudo-second-order model with a high correlation coefficient (R2) of 0.999. The thermodynamic coefficients (ΔH°, ΔS°, and ΔG°) were calculated from the temperature-dependent adsorption isotherms and illustrated that the adsorption of Hg(II) on the Fe3O4@PPy was spontaneous and endothermic. Different desorption agents were used to recover Hg(II) adsorbed onto Fe3O4@PPy, and a satisfactory recovery percentage of 93.0% was obtained by using 0.1 M HCl and 0.05 M NaCl. HIGHLIGHTS Amino-functional magnetic Fe3O4@PPy microspheres were prepared and characterized.; The Hg(II) can be adsorbed by Fe3O4@PPy effectively.; The used Fe3O4@PPy could be regenerated by two-component desorbent of HCl and NaCl.;

Qian Deru, Zheng Junhua, Gao Runfeng et al.

The MWD tool for formation pressure is composed of mechanical, electronic and hydraulic components. The internal installation space is small, the structure is complex, and the integration is difficult. In order to reduce the research and development risk of the tool, the formation pressure simulation gauging nipple was developed firstly. The 3D visualization technology was used to establish the virtual digital prototype of the simulation gauging nipple. The hydraulic valve insertion technology was used to study the key modules such as the micro hydraulic system with an output pressure of 20 MPa. Meanwhile, a formation pressure simulation test apparatus was developed as a platform for indoor high-temperature and high-pressure test and test principle verification of simulation gauging nipple. Actual measurement shows that the simulation gauging nipple runs stably at 120 ℃ and 60 MPa. Cores with permeability of 1×10^-3 μm² and 320×10^-3 μm² were selected to investigate the gauging nipple test principle, obtaining the formation pressure test curve, with measurement accuracy reaching 96%. The laboratory test verified the correctness of the measurement principle of the simulation gauging nipple and the accuracy of the measurement data. The research results lay a solid foundation for the development of formation pressure MWD engineering prototype.

Ye Cui, Di Liu, Yang Zhang et al.

A TA1 (Ti alloy)/low alloy steel (LAS) composite plate was manufactured by explosive welding. The effects of the bonding interface microstructure on the mechanical properties and fracture behavior of the composite plate were investigated. The results show that the interface has a wavy structure with intermetallic compounds (IMCs) enclosed by a steel matrix. The metallurgical bonding interface was achieved by local diffusion, with a several micrometer-thick diffusion layer. Two kinds of microcracks were formed in the IMC region and the diffusion interface. Microcracks in the IMC region propagate with difficulty due to the impediment of the IMC/steel interface. The microcracks initiated at the interface need to propagate into the fine-grain steel matrix before crack connection and delamination. The shear strength of the TA1/LAS composite plate was over 350 MPa. The composite plate could be bent up to the equipment limit (135 degrees). Excellent mechanical properties were obtained since the crack propagation was hindered by the refined or elongated steel grains induced during explosive welding.

Caoxing Huang, Xucai Wang, Chen Liang et al.

Abstract Background Prehydrolyzate, which is from the prehydrolysis process in dissolving pulps industry, contains various sugar-derived and lignin compounds such as xylooligosaccharides (XOS), gluco-oligosaccharides, xylose, glucose, and soluble lignin (S-L). The XOS has several beneficial effects on human physiology. XOS and S-L in prehydrolyzate are difficult to efficiently fractionate due to their similar molecular weights and water solubility. In this work, we proposed a sustainable and green process using polystyrene divinylbenzene (PS-DVB) resin to simultaneously separate and recover XOS and S-L. Enzymatic hydrolysis with endo-1,4-β-xylanase and fermentation with P. stipites were sequentially applied to purify XOS to minimize xylose content as well as amplify contents of xylobiose and xylotriose. In addition, 2D-HSQC NMR was used to analyze the structural characteristics of XOS and S-L. Furthermore, the biological abilities of antioxidants and prebiotics of these fractions were investigated by scavenging radicals and cultivating intestinally beneficial bacterias, respectively. Results Results showed that PS-DVB resin could simultaneously separate XOS and solubilized lignin with excellent yields of 93.2% and 85.3%, respectively. The obtained XOS after being purified by enzymatic hydrolysis and fermentation contained 57.7% of xylobiose and xylotriose. 10.4% amount of inherent xylan was found in the S-L fraction obtained by PS-DVB resin separation. 2D-HSQC NMR revealed that lignin carbohydrate complexes existed in both XOS and S-L as covalent linkages between lignin and 4-O-methylglucuronoarabinoxylan. The biological application results showed that the antioxidant capacity of S-L was stronger than XOS, while XOS was superior in promoting growth of intestinal Bifidobacteria adolescentis and stimulating production of short-chain fatty acids by Lactobacillus acidophilus. Conclusions The proposed strategy of sequentially combining hydrophobic resin separation, enzymatic hydrolysis, and fermentation was successfully demonstrated and resulted in simultaneous production of high-quality XOS and solubilized lignin. These biomass-derived products in prehydrolyzate can be regarded as value-adding prebiotics and antioxidants.

Xianpeng Zhou

The energy-saving effect of chemical plants is influenced by many factors, it is a complicated and systematic project to evaluate it scientifically and objectively. On the basis of the evaluation criteria of green energy-saving effects of public buildings and factories at home and abroad, this paper combines with the development status of China's chemical industry, formulates the principle for the selection of evaluation indicators for the energy-saving evaluation system of chemical plant green buildings, selects relevant contents including land resources, energy, water resources, and materials as evaluation indicators; this paper uses Analytic Hierarchy Process (AHP) to calculate the weights of the evaluation indicators in the evaluation system, the results show that, energy, water, and materials account for the largest proportion of the entire evaluation system, and it’s the focus of the energy-saving effect of the chemical plants buildings; at last, this paper constructs energy consumption indicators of chemical plant green buildings to evaluate the comprehensive effect of building energy conservation.

S. Mutlu, Y. Mennah Govela, F. Marra et al.

Preparation method may influence acid diffusion and buffering capacity of foods, which will consequently influence food breakdown and nutrient release during gastric digestion. The objective of this study was to determine the acid uptake into red beets during in vitro gastric digestion and characterize the buffering capacity of red beets as a result of different preparation methods. Red beets were cut into cylinders and they were examined as raw, steamed (15 min at 105°C) or pickled (steamed 15 min at 105°C, 7 days immersed in 2% acetic acid). Cylinders were covered to insulate their sides and back to have a one-dimensional diffusion system, before soaking in simulated gastric juice for up to 96 h (37°C). Before digestion, buffering capacity was measured by adding 0.2 M HCl to blended raw, steamed, or pickled beets until the pH value was below 1.5. After digestion, acidity measurements were performed. Acidity was significantly influenced by preparation method and digestion time (p < 0.05). Acidity of raw beets had the greatest increase from 0.46 mmol H+/g dry matter to 3.71 mmol H+/g dry matter during 96 hours of incubation. On the contrary, decrease of acidity was observed in pickled beets during 96 hours of incubation (15.28 mmol H+/g dry matter to 7.50 mmol H+/g dry matter). Preparation method significantly influenced buffering capacity (p < 0.001). Pickled beets had a higher buffering capacity of 0.051 mmol H+/(pH g) compared to raw and steamed beets which had buffering capacity values of 0.035 and 0.034 mmol H+/(pH g), respectively. Beet resistance to changes in pH, or buffering capacity, may cause differences in acid uptake of red beets in the gastric environment after different preparation methods. Higher acid uptake (3.25 mmol H+/g dry matter) was observed in raw beets with respect to steamed beets (2.35 mmol H+/g dry matter) during 96 hours of incubation as a result of higher buffering capacity and structural changes due to preparation method. The study of the relationship between food preparation and behavior during digestion can be important for development of innovative functional food products for specific consumer groups.

D. Himmelblau, J. B. Riggs

Stanisław WRZESIEŃ, Michał JASZTAL

Discs of ventube fan rotor were chosen as an object of the study. As a result of an analytical calculation, distribution of radial and circumferential stress and safety factor along rotor’s disc radius was calculated. Present paper displays relation between reliability function of structure element and safety factor through introducing probabilistic description of its value. Presented form of the reliability function gave the possibility of influence’s estimation of stress and strength’s variate dispersion round the expected value on reliability of structure element. Authors weighed deterministic value of safety factor against its value calculated in probabilistic way for various stress and strength distribution parameters.

Anne J. Herrington

This study investigated the context for writing in two college chemical engineering classes, viewing each as a disciplinary community. The study used a combination of quantitative and qualitative methods: a survey of all students and professors participating in these classes, open-ended and discourse-based interviews with ten students and two teachers, observation of classes, and analysis of claims and warrants used in students' written reports. The findings indicate that these two courses represented distinct communities where different issues were addressed, different lines of reasoning used, different writer and audience roles assumed, and different social purposes served by writing. These find- ings show the function that writing can serve in introducing students not only to the intellectual activities of a discipline, but also to the social roles and purposes of various disciplinary communities. The findings also show some of the problems that arose in specific classroom contexts when professors gave students mixed messages as to the audience for writing and when no issue was perceived for writing.

A. Estokova, L. Palascakova

Building materials belongs to the sources causing direct radiation exposure, therefore the natural radionuclide content of building materials is necessary to be still discussed over the world. Cements cause direct radiation exposure because of their radium (226Ra), thorium (232Th) and potassium (40K) content. Like other construction materials, the natural level of radioactivity in cement gives rise to external and internal indoor exposure. This work is focused on the assessment of natural radioactivity of cements commonly used in the Slovak Republic. The cement samples of CEM I, CEM II, CEM III and CEM V types from the significant Slovak cement producers were analyzed in the experiment. The samples were tested for the radionuclides content by using gamma spectroscopic measurements. The radionuclides activity in the Portland cements ranged from 5.8 – 21.6 Bq kg-1, 16.0 – 38.23 Bq kg-1 and 52.0 – 733.6 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The measured radionuclides content was compared to the specific requirements in relation to the Slovak eco-labelling process. The index of mass activity of natural radionuclides (gamma index) in cements was calculated in the range from 0.122 – 0.484.