Addition Of Amount Research Articles

Molecular modification of cyclodextrin glucosyltransferase and its application in the synthesis of α-arbutin

α-arbutin has important applications in cosmetics and medicine. However, the extraction yield from plant tissues is relatively low, which restricts its application value. In this study, we investigated the synthesis of α-arbutin using maltodextrin as the donor and hydroquinone as the acceptor, using a cyclodextrin glucosyltransferase (CGTase) from Anaerobranca gottschalkii. We performed site-saturated and site-directed mutagenesis on AgCGTase. The activity of the variant AgCGTase-F235G-N166H was 3.48 times higher than that of the wild type. Moreover, we achieved a conversion rate of 63% by optimizing the reaction pH, temperature, and hydroquinone addition amount. Overall, this study successfully constructed a strain with improved conversion rate for the synthetic production of α-arbutin and hydroquinone. These findings have significant implications for reducing the industrial production cost of α-arbutin and enhancing the conversion rate of the product.

Synthesis of Ag2O/CaMoO4 S-type heterojunction with enhanced sonocatalytic performance to remove crystal violet in dye wastewater

Herein, an S-type of Ag2O/CaMoO4 heterojunction was prepared by combining CaMoO4 with Ag2O and characterized. The sonocatalytic performance of the Ag2O/CaMoO4 composite was evaluated by analyzing the degradation of basic dye crystal violet (CV). The results showed that the Ag2O/CaMoO4 composite had the best sonocatalytic performance when the molar ratio of Ag2O to CaMoO4 in the Ag2O/CaMoO4 composite was 10 %. When the ultrasonic time was 120 min, the ultrasonic power was 200 W, the addition amount of 10 % Ag2O/CaMoO4 composite was 1.00 g/L and the initial concentration of CV solution was 5 mg/L, the removal rate of CV could reach 97.36 ± 1.46(%). In addition, 10 % Ag2O/CaMoO4 composite showed excellent sonocatalytic degradation performance to cationic dyes Rhodamine B (RhB) and methylene blue (MB), anionic dye Orange II (AO II) and azo dye Congo red (CR), indicating that the catalyst had a wide range of application. The study on the mechanism of sonocatalysis showed that the construction of S-type Ag2O/CaMoO4 heterojunction effectively separated the electron-hole (e−-h+) pairs in the sonocatalysis process, significantly improved the sonocatalytic performance of CaMoO4, and effectively degraded CV, and the degradation of CV was caused by the active components such as h+, superoxide anion radical (O2–) and hydroxyl radical (OH). Furthermore, the 10% Ag2O/CaMoO4 composite showed excellent repeatability and stability. In addition, the sonocatalytic degradation products of CV were detected and the possible degradation pathways of CV were summarized. These results suggested that the Ag2O/CaMoO4 composite was an extremely appropriate sonocatalyst for sonocatalytic degradation of organic pollutants and would provide a valuable research basis for the development of efficient sonocatalysts.

Improvement in the thermal conductivities and bending strengths of graphite film/Cu composites by matrix alloying with Zr

Graphite film/Cu composites were fabricated by the hot-pressing sintering method. The thermal conductivities and bending strengths of the composites were improved by matrix alloying with Zr. By sanding the surface of the graphite film, carbides were easily generated at the interface. The presence of carbides at the interface transformed the interfacial bonding characteristics from mechanical to physical-chemical bonding. Enhanced interfacial bonding could improve the thermal conductivity of the composites. The optimum Zr addition amount was 1.5 wt%, and the thermal conductivity of the composites was 725 W/mK. The enhanced interfacial bonding improved the composite bending strength. When the Zr concentration was 2 wt%, the composite bending strength was 34 MPa, which was an increase of 100 % compared with that of the absence of Zr.

Enzymatic conversion of camellia seed oil into glycerol esters: Synthesis and characterization

AbstractThe conversion of triacylglycerols in edible oils into diacylglycerols (DAGs) is of great significance for obtaining products with health benefits. Camellia seed oil (C‐oil), which is rich in oleic acid and linoleic acid, is an excellent raw material for the production of DAGs. In this study, single factor optimization experiments were carried out for hydrolysis and esterification respectively. Using Lipozyme® RM IM as catalyst, the maximum percent of C‐oil hydrolysis reached 87.14% at the reaction temperature of 60°C, reaction time of 24 h, water content of 30% and enzyme addition amount of 4%. The maximum content of camellia seed oil diacylglycerol (C‐DAG) reached 62.49% under the conditions of Lipozyme® RM IM as catalyst, vacuum system, 3% enzyme addition, 2% water addition, reaction temperature of 50°C and substrate molar ratio of free fatty acid to glycerol of 1:1. The high content of DAG was obtained by a coupled method, which eliminated the purification steps and reduced production costs. C‐oil and C‐DAG have been characterized by GC, TG, DSC, and GC‐IMS. Our results showed that the enzymatic coupling method did not affect the structural of the substances, but did affect the crystallization and melting properties of the oils. Moreover, the taste of C‐DAG was more delicate than C‐oil. Finally, the reaction mechanism was analyzed using FTIR spectroscopy, revealing that C‐oil was primarily hydrolyzed into free fatty acids. C‐DAG exhibited ester C‐O stretching vibrations in the range 1280–1030 cm−1, indicating successful esterification reaction between camellia seed oil free fatty acids (C‐FFAs) and glycerol catalyzed by lipases.

Effects of Emulsifiers on Physicochemical Properties and Carotenoids Bioaccessibility of Sea Buckthorn Juice.

The need to improve the physicochemical properties of sea buckthorn juice and the bioavailability of carotenoids is a major challenge for the field. The effects of different natural emulsifiers, such as medium-chain triglycerides (MCTs), tea saponins (TSs) and rhamnolipids (Rha), on the physical and chemical indexes of sea buckthorn juice were studied. The particle size of sea buckthorn juice and the carotenoids content were used as indicators for evaluation. The effects of different addition levels of MCT, Rha and TS on the bioavailability of carotenoids in sea buckthorn juice were investigated by simulating human in vitro digestion tests. The results showed that those emulsifiers, MCT, Rha and TS, can significantly reduce the particle size and particle size distribution of sea buckthorn juice, improve the color, increase the soluble solids content, turbidity and physical stability and protect the carotenoids from degradation. When the addition amount of Rha was 1.5%, the total carotenoids content (TCC) of sea buckthorn juice increased by 45.20%; when the addition amount of TS was 1.5%, the total carotenoids content (TCC) of sea buckthorn juice increased by 37.95%. Furthermore, the bioaccessibility of carotenoids was increased from 36.90 ± 2.57% to 54.23 ± 4.17% and 61.51 ± 4.65% through in vitro digestion by Rha and TS addition, respectively. However, the total carotenoids content (TCC) of sea buckthorn juice and bioaccessibility were not significantly different with the addition of MCT. In conclusion, the findings of this study demonstrate the potential of natural emulsifiers, such as MCT, Rha and TS, to significantly enhance the physicochemical properties and bioavailability of carotenoids in sea buckthorn juice, offering promising opportunities for the development of functional beverages with improved nutritional benefits.

Enhancement of fracture toughness of sol-gel silica glass coating by small amount of silver particle dispersion

Glass coatings find application across diverse fields, offering chemical resistance, insulation, and hardness to substrates. Toughness enhancement of glass coatings is strongly required to maintain these functions in the practical applications. In this study, we propose a novel approach to improve fracture toughness of glass coating by incorporating silver particles into it prepared via the sol-gel method. Samples with 0–2.0 vol% of 73 nm and 730 nm Ag particles in the precursor solution were obtained. The resulting samples exhibited high transparency, minimal change in Young's modulus, and considerably improved fracture toughness. At 73 nm and 730 nm, the maximum fracture toughness occurred at 0.5 vol% and 1.0 vol%, respectively, with a 1.4- and 1.8-fold increase compared to the original coating. This approach shows promise for enhancing glass coating toughness with minimal additive amounts and negligible loss of coating properties.

Ultra-wide temperature range aqueous electrolyte through local aggregation anchoring active water towards practical aqueous zinc metal battery

The key to realizing the application of aqueous electrolytes to extreme environments lies in rational constraints on active water. Herein, a strategy for local aggregation electrolyte (LA-Zn(OTf)2) with dynamic anchoring of active H2O is proposed and achieved by precisely regulating the molecular weight and addition amount of organic long chains enriched with hydrogen-bond acceptors. The results show that the saturated vapor pressure of LA-Zn(OTf)2 is reduced by 16 % at 90 °C and it does not freeze at -30 °C, achieving a wide operating temperature range of 120 °C. In LA-Zn(OTf)2, the local aggregation of Zn2+, solvent water, and ether bonding groups form a contact ion pair (CIP) structure, which enables rapid and stable deposition of Zn metal. Moreover, a stable organic-inorganic solid electrolyte interface (SEI) is formed to suppress corrosion and hydrogen evolution. At room temperature, the Zn|LA-Zn(OTf)2|Zn symmetric cell is stably cycled for over 4000 h at 1 mA cm-2. At the extreme temperatures of 90 and -30 °C, the Zn|LA-Zn(OTf)2|NVO full cells achieve stable cycling more than 1400 and 2000 cycles at 0.5 A g-1, respectively, and the capacity retention rates are 70.1 % and 80.5 %, respectively.

Synthesis of iron-manganese bimetallic materials supported by activated carbon and application of activated persulfate in the degradation of soil contaminated by crude oil

Heterogeneous catalytic processes based on zero-valent iron (ZVI) have been developed to treat soil and wastewater pollutants. However, the agglomeration of ZVI reduces its ability to activate persulfate (PS). In this study, a new Fe–Mn@AC activated material was prepared to activated PS to treat oil-contaminated soil, and using the microscopic characterization of Fe–Mn@AC materials, the electron transfer mode during the Fe–Mn@AC activation of PS was clarified. Firstly, the petroluem degradation rate was optimized. When the PS addition amount was 8%, Fe–Mn@AC addition amount was 3% and the water to soil ratio was 3:1, the petroluem degradation rate in the soil reached to the maximum of 85.69% after 96 h of reaction. Then it was illustrated that sulfate and hydroxyl radicals played major roles in crude oil degradation, while singlet oxygen contributed slightly. Finally, the indigenous microbial community structures remaining after restoring the Fe–Mn@AC/PS systems were analyzed. The proportion of petroleum degrading bacteria in soil increased by 23% after oxidation by Fe–Mn@AC/PS system. Similarly, the germination rate of wheat seeds revealed that soil toxicity was greatly reduced after applying the Fe–Mn@AC/PS system. After the treatment with Fe–Mn@AC/PS system, the germination rate, root length and bud length of wheat seed were increased by 54.05%, 7.98 mm and 6.84 mm, respectively, compared with the polluted soil group. These results showed that the advanced oxidation system of Fe–Mn@AC activates PS and can be used in crude oil-contaminated soil remediation.

Fast, Efficient Tailoring Growth of Nanocrystalline Diamond Films by Fine-Tuning of Gas-Phase Composition Using Microwave Plasma Chemical Vapor Deposition.

Nanocrystalline diamond (NCD) films are attractive for many applications due to their smooth surfaces while holding the properties of diamond. However, their growth rate is generally low using common Ar/CH4 with or without H2 chemistry and strongly dependent on the overall growth conditions using microwave plasma chemical vapor deposition (MPCVD). In this work, incorporating a small amount of N2 and O2 additives into CH4/H2 chemistry offered a much higher growth rate of NCD films, which is promising for some applications. Several novel series of experiments were designed and conducted to tailor the growth features of NCD films by fine-tuning of the gas-phase compositions with different amounts of nitrogen and oxygen addition into CH4/H2 gas mixtures. The influence of growth parameters, such as the absolute amount and their relative ratios of O2 and N2 additives; substrate temperature, which was adjusted by two ways and inferred by simulation; and microwave power on NCD formation, was investigated. Short and long deposition runs were carried out to study surface structural evolution with time under identical growth conditions. The morphology, crystalline and optical quality, orientation, and texture of the NCD samples were characterized and analyzed. A variety of NCD films of high average growth rates ranging from 2.1 μm/h up to 6.7 μm/h were successfully achieved by slightly adjusting the O2/CH4 amounts from 6.25% to 18.75%, while that of N2 was kept constant. The results clearly show that the beneficial use of fine-tuning of gas-phase compositions offers a simple and effective way to tailor the growth characteristics and physical properties of NCD films for optimizing the growth conditions to envisage some specific applications.

Construction of phosphorus-containing polyimine vitrimer film by incorporating ionic liquid BMIM∙PF6 for enhanced mechanical, flame-retardant and reprocessable properties

A composited flame-retardant phosphorus-containing polyimine vitrimer films (Ionic-PIs) were synthesized by using ionic liquid BMIM∙PF6 containing flame retardant elements N, P and F as the regulator. The effects of the addition amount of BMIM∙PF6 on the mechanical properties, degradation, recycling, and flame retardancy were investigated. Compared to intrinsically phosphorus-containing polyimine film (PI), the composited Ionic-PIs exhibited better mechanical strength and toughness. Hydrogen bonding interactions between BMIM∙PF6 and polyimine network greatly increased Ionic-PI’s mechanical strength at a low addition of 1 wt%, and the microphase separation caused by the aggregation of BMIM∙PF6 drastically enhanced their toughness as the addition increased. Ionic-PIs exhibited excellent reprocessability at 85 °C and degradable recyclability under acidic conditions. In addition, due to the synergistic effect of condensed-phase and gas-phase flame-retardant mechanisms, the Ionic-PIs possessed good flame retardancy with LOI above 27 % and a UL-94 test reaching VTM-0 grade, which was important for the high-fire safety of polyimine vitrimer. This work is helpful to provide a simple and feasible strategy to modulate the comprehensive properties of cross-linked polyimine vitrimer film and to expand their applications in many fields.

Preparation of poly(lactic acid) grafted glycidyl neodecanoate by solid phase grafting and its compatibilization for poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) composite

AbstractPoly(lactic acid) (PLA) grafted glycidyl neodecanoate (GND) with a single epoxy group (PLA‐GND) is prepared in this paper by solid phase grafting, and the effects of different reaction conditions on the grafting percentage of PLA‐GND are investigated. Furthermore, PLA‐GND is used as a nonreactive compatibilizer to prepare PLA‐GND/PLA/poly(butylene adipate‐co‐terephthalate) (PBAT) composite by melt blending. The results show that PLA‐GND has the highest grafting percentage of 2.15% when the feed weight ratio of GND to PLA is 0.2, the feed weight ratio of triphenylphosphine to PLA is 0.02, the additive amount of xylene is 1 mL, the reaction temperature is 120°C, and the reaction time is 115 min. The GND segments of PLA‐GND and PBAT segments could form a physical entanglement microdomain because of the similar aliphatic chain of GND and PBAT, which would improve the compatibility of PLA and PBAT. PLA‐GND/PLA/PBAT composite has the highest tensile strength, elongation at break, impact strength, crystallinity, heat deformation temperature, and melt flow rate at a PLA‐GND content of 5%, which are 38.54 MPa, 118.65%, 15.83 kJ/m2, 5.71%, 65.3°C, and 36.3 g/10 min, 14.53%, 390.90%, 68.94%, 224.43%, 16.19%, and 224.40% higher than those of PLA/PBAT composite, respectively.Highlights PLA grafted GND with a single epoxy group is prepared by solid phase grafting. PLA‐GND as a non‐reactive compatibilizer compatibilizes PLA/PBAT composite. The similar chain of GND and PBAT is helpful to form the physical entanglement. The physical entanglement is essential to improve compatibility of PLA and PBAT. PLA/PBAT composite has excellent overall performance at a PLA‐GND content of 5 wt%.

Enhancing Tomato Production by Using Non-Conventional Water Resources within Integrated Sprinkler Irrigation Systems in Arid Regions

This research evaluated the importance of establishing an integrated sprinkler irrigation design connected to fish farm ponds in order to achieve environmental and financial benefits. To achieve the aim of the study, two field experiments were conducted at a private farm in the Nubaria area of Beheira Governorate during the 2022 and 2023 seasons to quantify all the benefits from using fish water effluent (FWE) in irrigation. The obtained results indicated that the effluent could represent a good source of irrigation and bio-fertilization. The yield of tomato was higher when using FWE for irrigation compared with using groundwater for irrigation (IW). This was due to the additional amounts of dissolved bio-nitrogen along with other nutrients present in the FWE. The proportion of dissolved nitrogen added by using FWE was 22.3 kg nitrogen per hectare in 2022 and 24.6 kg nitrogen per hectare in 2023, in addition to some other major elements such as phosphorus and potassium, which are also among the main nutrients needed by crops. It has also been noticed that the fertility of the sandy soil increased with the use of FWE for irrigation. One of the most important results was the possibility of reducing the addition of nitrogen mineral fertilizers by 25%, thus saving on N fertilizers when growing tomato. In addition to the vitality of the FWE and its macro- and microelements, algae, microorganisms, and other organic materials, the use of this type of water as an alternative source for irrigation, along with the reduction in the amount of added mineral fertilizers, will reduce the degree of groundwater contamination with mineral fertilizers and increase the income of farmers. It was also observed that the air temperature decreased during the growing season when compared with the temperature of uncultivated surrounding areas.

Research on the Application of New Polylactic Acid (PLA) Fiber Concrete Materials in Urban and Rural Flood Resistance

This paper aims to study and apply new polylactic acid (PLA) fiber concrete materials to improve urban and rural flood resistance, enhance flood control and drainage capabilities, and promote sponge city construction. Through the analysis of the characteristics, proportion optimization and performance of PLA fiber concrete in actual projects, it is found that the material has good mechanical properties, environmental adaptability, economy and environmental protection, and has important application prospects in urban and rural flood control and drainage. By adjusting the proportion, selecting the appropriate fiber type and addition amount, the flood resistance and drainage capacity of concrete can be improved. Combined with 3D printing technology and modern scientific and technological means, the application and development of PLA fiber concrete will be further promoted to achieve a win-win situation of continuous improvement of urban and rural flood resistance and environmental protection. With the support of relevant technologies and policies, PLA fiber concrete has broad application prospects in sponge city construction and urban and rural flood control and drainage, and will make important contributions to improving the level of urban and rural disaster prevention and mitigation.

Effects of conjugation of egg lysozyme to theaflavins on their structure and function

Proteins modified by polyphenols have more advantages. In this study, we investigated the effect of covalent conjugation of egg white lysozyme (LYZ) with theaflavin (TF) on its structure and related functions. The LYZ-TF covalent conjugation was prepared by an alkaline method (pH 9.0) with a branching rate of about 80%. The results such as SDS-PAGE and UV spectroscopy proved the formation of the covalent conjugation. The results of fluorescence and infrared spectroscopy showed that the conformation of the LYZ-TF coupling was altered, with an increase in α-helix content by more than 10% and an increase in surface hydrophobicity compared to LYZ. The results of relevant functional characterization experiments showed the thermal stability and antioxidant properties of LYZ modified by TF, but its enzymatic activity and in vitro antimicrobial properties were inhibited. Notably, the amount of TF addition also affected the structure and function of the conjugates. These results provide some theoretical guidance for the development of novel food functional materials with enhanced properties.

Dendroremediation of soil contaminated by mining sludge: A three-year study on the potential of Tilia cordata and Quercus robur in remediation of multi-element pollution

The vast amounts of mining and metallurgical wastes containing unimaginable quantities of toxic metal(loid)s require searching for managed ways. The study aimed to long-term assess the growth, elements accumulation (As, Cd, Hg, In, Mn, Mo, Pb, Sb, Sn, Ti, Tl, Zn) and proline content in 2-year-old Tilia cordata Mill. and Quercus robur L. seedlings growing under 1 and 3% extremely polluted mining sludge (MS) after 1, 2 and 3 years.Both species were able to grow efficiently without significant differences resulting from the impact of MS. The overall rise was higher for T. cordata than for Q. robur. The accumulation ability for As, Hg, In, Mn, Mo, Pb, Ti, and Zn in the whole plant was significantly higher for T. cordata, while Cd, Sb, Sn and Tl did not differ considerably between species. The highest content was found for As, Mn and Zn (68.7, 158, and 157 mg per plant, respectively) for T. cordata after 3 years of growth. The calculated Bioconcentration Factors were the highest for Cu (1.23), In (6.86), and Zn (38.4) for Q. robur, as well as for As (1.55), Hg (3.24), Mn (32.8), Mo (1.64) and Ti (18.0) for T. cordata after 3 years. The highest Translocation Factors were observed for In (1.35) and Sn (1.25) after 3 years, as well as for Mn (2.72, 3.38, and 3.03 after 1, 2, and 3 years) for Q. robur seedlings. The proline content was higher for Q. robur, regardless of which organ was examined, and the differences increased with the time of the experiment and the amount of MS addition (possibly more sensitive to stress).Young T. cordata seedlings show much greater potential than Q. robur. This is the first time that a demonstration of the high potential of long-living trees in multi-element MS remediation has been described.

The role of arabinoxylan purified from wheat bran in bread and biscuits: Impacts on digestibility and colonic fermentability in vitro

In this study, arabinoxylan (AX) isolated from wheat bran was used to prepare AX-fortified bread and biscuits, and the effects of the amount and method of AX addition on the nutritional properties of baked products were investigated through simulated digestibility and colonic simulated fermentability analysis in vitro. The purified AX demonstrated a high total sugar content (92.75%), high molecular weight (Mw) (669.8 kDa), low polymer dispersity index (PDI) and low arabinose to xylose (A/X) ratio (1.21). In vitro digestibility test indicated that AX addition could dose-dependently inhibit the starch digestibility in both bread and biscuits. Most importantly, it could also dose-dependently transfer more starch and protein into the colon through the gastrointestinal tract, leading to the changes in total amount and chemical composition of food residues. Results from the in vitro fermentability test showed that alterations in the composition of food residue affected its fermentability: a high relative ratio of carbohydrate to protein could enhance its prebiotic effect. This study provides valuable insights into the role of dietary fibres in baked foods, aiming to achieve precise nutrition for high-fibre food products.

Onions, Salt and Palm Oil Marination Reduced Polycyclic Aromatic Hydrocarbon in Cooked Chevon and Beef Meat: A Risk Assessment Study

The roles of foods in human health can be greatly influenced by processing. The process of singeing deposits polycyclic aromatic hydrocarbons (PAHs) on meat. However, some food additives have shown tendencies to reduce PAHs levels in singed food. This study conducted a risk assessment study on the effect of onions, salt and palm oil marination on Polycyclic aromatic hydrocarbon in cooked chevon and beef meat. The singed meat samples were cooked with specific quantities of additives (onions, salt and palm oil). PAHs levels were analyzed using Gas Chromatography Mass spectrophotometer (GC-MS) and the health risk assessment was conducted as described by USEPA. Our findings revealed that meat samples singed with augmented fire wood accumulated more PAHs than those singed with only firewood; also chevon accumulated more PAHs than beef. PAHs content in all singed meat samples cooked with maximum quantity of additives (15 g) for 30 min had reduction in concentration of about 99%. The estimated daily intake (EDI) showed that PAHs concentration were higher in uncooked meat samples singed with augmented firewood. The least concentration of PAH was seen in cooked chevon singed with only firewood (9.39E-06 mg/kg/day). The hazard quotients (HQs) evaluated showed that cooking the meat samples with additives, notably decreased PAHs concentration (from between 10−1 and 10−3 to between 10−5 and 10−7). The hazard index (HI) observed showed that PAHs concentration in cooked samples were lower than in uncooked samples. The Carcinogenic potency showed that the uncooked singed meat samples could lead to health complications except for the chevon sample singed with only firewood. However, all cooked samples showed lower health hazards with potency index which were all less than one (<1). The findings suggest that chevon accumulated PAHs more than beef. However, the carcinogenic potency of the PAHs in chevon was less than beef after cooking with additives.

Influences of Cu content on the microstructure and reinforcing behavior of network AlN/Al composites at 350 °C

Reinforcement configuration of Al composites has recently been at the center of attention. In this study, through the analysis of microstructure and tensile properties, effects of Cu content on the reinforcing behaviors of AlN network were investigated in details. Results indicated that the increasing amount of Cu would form micron Al2Cu which would decorated on the AlN network. With the increasing amount of Cu addition from 1.5% to 6%, the particle size of Al2Cu increased from 1 μm to 10 μm. Besides the micron Al2Cu, Cu elements were also existed in θ′ precipitates in the region where were poor of AlN and segregated on the surface of AlN. Given the microstructure changes with different Cu addition, the tensile properties at room temperature increased with Cu addition while the average tensile strength at 350 °C were decreased from 102 MPa to 85 MPa. The addition of elements would affect the bearing capacity of the 8.2AlN/Al–Cu composites at 350 °C. Firstly, the micron Al2Cu phase would suffer the load and get stress concentration. It would lead to the premature imitation of voids and strongly impair the strengthening behavior of AlN network. Secondly, the nano θ′ precipitates would become coarsen and the hinder effects of dislocation would be enhanced at 350 °C. Finally, the segregated Cu atoms on the AlN surface could increase the deformation coordination of AlN network and help decrease the stress concentration.

Screening and Identification of High-Yielding Strains of Conjugated Linoleic Acid and Optimization of Conditions for the Conversion of CLA.

Conjugated linoleic acid (CLA) is a class of naturally occurring octadecadienoic acid in humans and animals and is a general term for a group of conformational and positional isomers of linoleic acid. In order to obtain the development of excellent lactic acid strains with a high production of conjugated linoleic acid, 32 strains with a possible CLA conversion ability were obtained by initial screening using UV spectrophotometry, and then the strains were re-screened by gas chromatography, and finally, the strain with the highest CLA content was obtained. The strains were optimized for cultivation by changing the amount of substrate addition, inoculum amount, and fermentation time. The results showed that the yield of the experimentally optimized strain for the conversion of conjugated linoleic acid could reach 94.68 ± 3.57 μg/mL, which was 74.4% higher than the initial yield of 54.28 ± 2.12 μg/mL of the strain. The results of this study can provide some basis for the application of conjugated linoleic acid production by Lactobacillus paracasei in the fermentation of lactic acid bacteria.

CFD Characterization and Field Test Study on Plugging Air Leakage with Time-Varying Viscosity Solidified Foam to Prevent Coal Spontaneous Combustion

ABSTRACT From the perspective of plugging air leakage paths and preventing coal spontaneous combustion in the goaf of coal mines, filling and plugging the ends of the working face is crucial. Generally speaking, rapidly solidified foam slurry is beneficial to plugging air leakage paths. However, researchers have not yet clarified the accumulation and diffusion rules of rapidly solidified foam, resulting in low efficiency in plugging air leakage paths. To solve the above problems, this study takes the goaf of 1301 working faces of the Shandong Lilou Coal Industry as the research object, uses the computational fluid dynamics modeling method to construct a physical model of pressure injection foam slurry, and optimizes the on-site application process parameters of plugging the end of the working face. The numerical simulation results show that coagulant can improve the accumulation characteristics and plugging efficiency of foam slurry, and the optimal addition amount is 3 wt%. In addition, as the perfusion flow increases from 5 to 15 m3/h, the airflow rates on the working face gradually increases and the oxidation zone gradually shrinks. Therefore, the grouting flow is preferably 15 m3/h. Field test results show that rapid-setting inorganic solidified foam blocks the airflow at the air inlet corner from leaking into the goaf and weakens the composite reaction of coal and oxygen. The temperature at each monitoring point first decreased, then stabilized, and the final temperature was maintained at 27-28°C. The CO concentration gradually decreased and finally remained below 20 ppm. The CO concentration of the mine’s total return airflow is stable below 10 ppm. This study can provide theoretical guidance for the technological design of using solidified foam to rapidly plug the air leakage paths at the end of the fully mechanized caving working face.