Series Of Single-factor Experiments Research Articles

Screening of cellulose-degrading bacteria and optimization of cellulase production from Bacillus cereus A49 through response surface methodology

Cellulose-degrading microorganisms hold immense significance in utilizing cellulose resources efficiently. The screening of natural cellulase bacteria and the optimization of fermentation conditions are the hot spots of research. This study meticulously screened cellulose-degrading bacteria from mixed soil samples adopting a multi-step approach, encompassing preliminary culture medium screening, Congo red medium-based re-screening, and quantification of cellulase activity across various strains. Particularly, three robust cellulase-producing strains were identified: A24 (MT740356.1 Brevibacillus borstelensis), A49 (MT740358.1 Bacillus cereus), and A61 (MT740357.1 Paenibacillus sp.). For subsequent cultivation experiments, the growth curves of the three obtained isolates were monitored diligently. Additionally, optimal CMCase production conditions were determined, keeping CMCase activity as a key metric, through a series of single-factor experiments: agitation speed, cultivation temperature, unit medium concentration, and inoculum volume. Maximum CMCase production was observed at 150 rpm/37 °C, doubling the unit medium addition, and a 5 mL inoculation volume. Further optimization was conducted using the selected isolate A49 employing response surface methodology. The software model recommended a 2.21fold unit medium addition, 36.11 °C temperature, and 4.91 mL inoculant volume for optimal CMCase production. Consequently, three parallel experiments were conducted based on predicted conditions consistently yielding an average CMCase production activity of 15.63 U/mL, closely aligning with the predicted value of 16.41 U/mL. These findings validated the reliability of the model and demonstrated the effectiveness of optimized CMCase production conditions for isolate A49.

Extraction, Isolation and Biological Activity of Two Glycolipids from Bangia fusco-purpurea.

In order to explore the extraction and activity of macroalge glycolipids, six macroalgae (Bangia fusco-purpurea, Gelidium amansii, Gloiopeltis furcata, Gracilariopsis lemaneiformis, Gracilaria sp. and Pyropia yezoensis) glycolipids were extracted with five different solvents firstly. Considering the yield and glycolipids concentration of extracts, Bangia fusco-purpurea, Gracilaria sp. and Pyropia yezoensis were selected from six species of marine macroalgae as the raw materials for the extraction of glycolipids. The effects of the volume score of methanol, solid-liquid ratio, extraction temperature, extraction time and ultrasonic power on the yield and glycolipids concentration of extracts of the above three macroalgae were analyzed through a series of single-factor experiments. By analyzing the antioxidant activity in vitro, moisture absorption and moisturizing activity, the extraction process of Bangia fusco-purpurea glycolipids was further optimized by response surface method to obtain suitable conditions for glycolipid extraction (solid-liquid ratio of 1:27 g/mL, extraction temperature of 48 °C, extraction time of 98 min and ultrasonic power of 450 W). Bangia fusco-purpurea extracts exhibited a certain scavenging effect on DPPH free radicals, as well as good moisture-absorption and moisture retaining activities. Two glycolipids were isolated from Bangia fusco-purpurea by liquid-liquid extraction, silica gel column chromatography and thin-layer chromatography, and they showed good scavenging activities against DPPH free radicals and total antioxidant capacity. Their scavenging activities against DPPH free radicals were about 60% at 1600 µg/mL, and total antioxidant capacity was better than that of Trolox. Among them, the moisturizing activity of a glycolipid was close to that of sorbierite and sodium alginate. These two glycolipids exhibited big application potential as food humectants and antioxidants.

Experimental and numerical investigations into the fabrication of alumina ceramic surface microchannel by electrochemical discharge machining

The electrochemical discharge machining (ECDM) is an advanced and promising technology for fabricating micro structures. This method is effectively applicable for non-conductive hard and brittle materials micromachining, such as glass and ceramics. However, the ceramics high melting point and intense heat exchange effects during microchannel fabrication lead to the easy dissipation of thermal energy and the difficulty in processing. To address this issue and expanded the ECDM processing range. This paper dedicated to the investigation of the material removal mechanism and process characteristics for the alumina ceramic surfaces microchannels preparation. Firstly, this study explained the difference of the ECDM critical applied voltage and gas film generation mechanism by analyzing the volt-ampere characteristic curve of 20 wt% NaOH electrolyte with a tool immersed depth of 2 mm and 10 mm respectively. Then, a thermal removal finite element model (FEM) for ECDM was developed. The heat cumulative and intermittent cooling effects applied on the alumina ceramic surface dominated the materiel removal. Additionally, it can be found that the microchannel machining accuracy and bottom surface quality depended on the Gaussian heat source characteristics, gas film formation mechanism, heat accumulation effect, and temperatures spatial and temporal distribution. And a series of single factor experiments for evaluating the parametric studies such as the effect of discharge frequency, applied voltage, duty ratio and tool feed rate on the fabricated microchannel performance are executed. Finally, the complex three-dimensional structures of cross microchannel grid and zigzag microchannel array with variable depth were successfully fabricated on aluminum oxide ceramic surface. Notably, the results highlighted and enriched the ECDM stability, consistency and applicability for alumina ceramic surface microchannel fabrication.

Coagulation pretreatment coupled with indigenous microalgal-bacterial consortium system for on-site treatment of rural black wastewater

Improper treatment of rural black wastewater (RBW) presents substantial challenges, including the wastage of resource, environmental contamination, and economic consequences. This study proposed an integrated process for RBW treatment, consisting of coagulation/flocculation (C/F) pretreatment and subsequent inoculation of indigenous microalgal-bacterial consortium (IMBC) for nitrogen recovery, namely C/F-IMBC process. Specifically, the optimal C/F conditions (polyaluminium chloride of 4 g/l, polyacrylamide of 50 mg/l, and pH of 6) were determined through a series of single-factor experiments, considering CN, turbidity, and dissolved organic matter (DOM) removal, economic cost, and potential influence on the water environment. Compared to the sole IMBC system for RBW treatment, the proposed C/F-IMBC process exhibited a remarkable 1.23-fold increase in microalgal growth and a substantial 17.6–22.6 % boost in nitrogen recovery. The altered RBW characteristic induced by C/F pretreatment was supposed to be responsible for the improved system performance. In particular, the abundance of DOM was decreased and its composition was simplified after C/F pretreatment, based on the analysis for excitation-emission matrices with parallel factor and gas chromatography–mass spectrometry, thus eliminating the potential impacts of toxic DOM components (e.g., Bis(2-ethylhexyl) phthalate) on IMBC activity. It should also be noted that C/F pretreatment modified microbial community structure as well, thereby regulating the expression of nitrogen-related genes and enhancing the system nitrogen recovery capacity. For instance, the functional Cyanobacteria responsible for nutrient recovery was enriched by 1.95-fold and genes involved in the assimilatory nitrate reduction to ammonia pathway were increased by 1.52-fold. These fundamental findings are expected to offer insights into the improvement of DOM removal and nitrogen recovery for IMBC-based wastewater treatment system, and provide valuable guidance for the development of sustainable on-site RBW treatment technologies.

One-step solvothermal synthesis of MoS2@Ti cathode for electrochemical reduction of Hg2+ and predicting BP neural network model

Although mercury is one of the heavy metal pollutants that endanger human health and the environment, it is also an essential raw material needed for industrial development. We try to use electrochemical reduction method to realize the resource utilization of mercury. MoS2@Ti electrodes were prepared using a one-step solvothermal method, and XRD, XPS, SEM and EDS were used to analyze the MoS2 powder. The prepared highly reactive MoS2@Ti electrode was used as a cathode to electrochemically reduce the mercury-containing solution. After a series of single-factor experiments, under the conditions of stirring rate of 400 r/min, electrode spacing of 20 mm, constant potential of 2 V and electrolytic time of 2 h, the removal efficiency of Hg2+ in 10 ∼ 50 mg/L HgSO4-10 % H2SO4 solution reached 94.5 % or above. The reaction mechanism of MoS2@Ti was investigated mainly by using the indirect reaction of superoxide radicals and hydrogen radicals to achieve the reduction of Hg2+. And the MoS2@Ti electrode can still reach 80.0 % removal efficiency after five times of repeated use. A neural network model was used to predict the efficiency of Hg2+ reduction in this system with a high accuracy of RMSE 1.3049 and R2 0.9511. The above study contributes to the realization of the resource utilization of mercury.

A novel technology for phosphorus recovery from leaching residue of montebrasite by alkaline leaching and crystallization

Phosphate rock, a finite and non-renewable resource on earth, is facing the dilemma of resource depletion and quality decline, thus it is urgent to fully utilize any potential phosphorus resources. In this paper, a novel process combined alkaline leaching and crystallization for phosphorus recovery from the leaching residue of montebrasite (LRM) was proposed. The main component of LRM was determined to be AlPO4. Thermodynamic study of the Al3+-PO43--H2O system was carried out, which revealed that the complete dissolution region of AlPO4 were pH < 0.8 and pH > 12.2. Using NaOH as the leaching agent, a series of single factor experiments were conducted to determine the optimal leaching parameters. The results demonstrated that the extraction rates of P, Al and Si were 89.40%, 86.49% and 23.33%, respectively, at leaching temperature of 60 °C, leaching time of 1 h, liquid-to-solid ratio of 12 mL/g and NaOH concentration of 120 g/L. Moreover, phosphate in leach liquor was recovered in the form of Na3PO4 by crystallization. The recovery rate of P in leach liquor reached 95.72% at 5 °C for standing 24 h, whereas only 6.51% of Al was lost. The process proposed in this study provides the possibility of extracting phosphorus from a new potential phosphorus resource.

Research on influence of polishing fluids parameters on processing effects in reciprocating magnetorheological polishing

PurposeThis paper aims to study the influence of the different parameters of magnetorheological polishing fluids (MRP fluids) on the surface roughness and material removal rate (MRR) of the workpiece surface in the reciprocating magnetorheological polishing (RMRP) process.Design/methodology/approachA series of single-factor experiments are performed to evaluate the influence of the concentration of magnetic particles, concentration of abrasive particles and size of abrasive particles on surface processing effects by using the RMRP method. Moreover, the yield stress and viscosity of MRP fluids are studied based on the Bingham plastic model by varying the MRP fluids parameters.FindingsA reasonable parameter of MRP fluids is crucial to the surface roughness and MRR of the workpiece surface, and the optimized parameters are obtained by the single-factor experiments of RMRP. The results are when the concentration of carbonyl iron particles is 40 Vol.%, the concentration of CeO2 is 5 Vol.% and the size of CeO2 is 2.5 µm in the MRP fluids, the surface roughness of the workpiece remarkably decreases to 28 nm from the initial 332 nm and the MRR of the workpiece increases to 0.118 mg/min.Originality/valueIn this study, the single-factor experiments for the different parameters of MRP fluids are studied to polish K9 glass by using the RMRP device, and the yield stress and viscosity of MRP fluids are investigated by rheological experiments, which provides reference for a reasonable selection of the MRP fluids parameter in RMRP process.

Mechanism and Kinetic Study on Synthesis of Methacrolein Catalyzed by Amine/Acid

Methacrolein (MAL) is an important intermediate extensively used in the manufacture of methyl methacrylate and other materials (polymers and resins). In this study, a series of secondary amines/acids were explored as catalysts for the condensation of formaldehyde and propionaldehyde to prepare MAL. It was found that the structure of the amines and acids directly affected the yield of MAL. The effect of the catalyst was closely related to the nucleophilicity of the amines as well as the steric hindrance effect, while acids also played a role as co-catalysts. Dibutylamine acetate was selected as the catalyst after investigation. The catalytic performance of the system was systematically studied by a series of single-factor experiments, including stirring rate, temperature, reaction time, acid/amine ratio, and the solvent, and the optimized reaction conditions were obtained. In the optimum condition, the yield of MAL was up to 97.3%. Kinetic experiments were performed for the condensation of formaldehyde and propionaldehyde to MAL, and the activation energies, reaction orders, and rate-limiting step of the reaction were determined. The results indicate that the decomposition of the Mannich base is a rate-limiting step.

Performance investigation and parameter optimization of ultra-light aerated concrete using orthogonal experimental design

In order to investigate the influence of different experimental conditions and additives on the performance of ultra-light aerated concrete (ULAC), more than 300 ULAC specimens with a dry density of around 160 kg/m3 were prepared in this study. The optimum conditions of the experimental process and the dosage range of three admixtures were obtained by two series of single-factor experiments. The results show that the unification of experimental conditions is necessary for the experimental process; the range of water-binder ratio (w/b) is 0.5 ∼ 0.52; the replacement ratio range of fly ash and silica fume are (Rf, 3∼6 %; Rsi, 3∼4 %); the amount of polypropylene fiber (Mpp) is 3∼5 %. Through orthogonal experimental design, the dependence of the compressive strength, flexural strength, dry density, thermal conductivity upon Rf, Rsi, w/b, Mpp, and conditioning agent (Ac, an inorganic material) of ULAC is here investigated. The impact of four factors and their interactions on all property indexes (PIs) was studied by analysis of variance. A modified multiple-index assessment method was proposed to optimize the parameter combination for four PIs of ULAC. The results show that the Rf is the significant influencing factor of all PIs, and the interactions among the three active additives significantly impact the performance of ULAC. Nevertheless, the interaction between Rf and w/b has little impact. The repeated tests show that the deviations between the property index and the target value obtained by the theoretical prediction model are 2.63 %, 2.59 %, 2 % and 4.79 %, respectively, and according to the comprehensive weighted scoring method, the deviations between them are 2.56 %, 1.44 %, 4 % and 4.6 %, respectively. The deviations obtained by the two methods are less than 5 %, demonstrating that this method could be widely used in the ULAC multi-index system parameter optimization.

Performance promotion of aluminum oxide capping layer through interface engineering for tunnel oxide passivating contacts

High-efficiency silicon solar cells depend on passivating contact structure to decrease recombination losses at the crystalline silicon (c-Si) surface and the interface of metal/Si contact. Tunnel oxide passivating contact (TOPCon) technology is one of these structures, in which heavily doped poly-Si is placed over a SiO x layer grown directly on the c-Si wafer. The passivation performance can be further improved by depositing a thin aluminum oxide (AlO x ) layer on one side of the symmetric cell structure, which is attributed to the reduced interfacial defects, facilitated formation of carrier collector layer, and excellent field-effect passivation. Atomic layer deposition (ALD) may be utilized to produce high-quality and pinhole-free AlO x capping layers due to its controllability, homogeneity, and conformality. However, insufficient substrate surface activity is a challenge faced in AlO x deposition because it can impair Al(CH 3 ) 3 nucleation, resulting in an island-like growth over the first few ALD cycles, ultimately deteriorating the passivation effect of AlO x . In this study, we optimized the deposition process of ALD AlO x through a series of single-factor experiments. Subsequently, alternative substrate treatment methods were tested to compare the performance. In particular, we proposed a two-step interface engineering process (chemical mechanical polishing + RCA SC-2 treatment) to enhance the comprehensive performance of the ALD AlO x layer, achieving a high iV OC of 726 mV and low J 0 of 5.4 fA/cm 2 , compared with a reference poly-Si/c-Si passivating contact ( iV OC = 703 mV, J 0 = 19.4 fA/cm 2 ). The result was interpreted in terms of gradually improving substrate surface quality and wettability, together with the gradually decreasing thickness of the interfacial oxide layer. The circumvent of the island growth mode improved the growth quality of the subsequent film, effectively compressed the ALD cycle needed for stable growth, and enhanced the passivation property. Altogether, the present data may guide further efforts to obtain high-efficiency silicon-based solar cells by arising the interface engineering. • The optimum ALD AlO x process parameters are determined to optimize the AlO x coating process for industrial production. • A novel two-step interface engineering process (CMP + RCA SC-2 treatment) is proposed. • The overall passivation quality of the AlO x capped symmetric structure can be improved and the ρ c can be reduced simultaneously.

Multifunctional β-Cyclodextrin Polymer for Simultaneous and Effective Removal of Organic Micropollutants, Heavy Metals, and Detrimental Microorganisms from Water

A new porous β-cyclodextrin-based polymer (PCD-Gs) adsorbent was synthesized by the copolymerization of allyl-β-CD and partially allylated gallic acid under different monomer feeding ratios. With a series of single-factor experiments, it was found that the PCD-Gs not only exhibited ultrarapid and efficient absorption capacity for bisphenol A and Cd(II) but also possessed strong bactericidal ability and good resistance to salt and acid. Multivariate analyses showed that there was no competitive adsorption but a positive effect between Cd(II) and bisphenol A on PCD-Gs in the binary system. Besides, the PCD-Gs had outstanding regeneration ability and removal efficiency even at environmentally relevant concentrations. Combined with 1H NMR analysis, a multimechanism was suggested that the polymer of PCD-Gs possesses multiple action sites and presents great potential for simultaneously and effectively removing organic micropollutants, metal ions, and detrimental microorganisms from contaminated water, which contributes to deep purification of water and simplification of the water treatment process.

Oblique ultrasonic vibration-assisted polishing for grating structures of BK7 optical glass

As a classical optical structure, grating is widely applied in semiconductor, biomedicine, and optical communication fields. However, the existing machining methods are difficult to accommodate the increasing requirements. A novel polishing method of optical glass BK7 was proposed based on ultrasonic vibration-assisted polishing with polishing oblique angle θ. It has better machining accuracy compared to common polishing. Finite element static analysis was performed to investigate the effect of polishing oblique angle on the processing of grating structures, and the feasibility and advantages of this method were illustrated theoretically. Meanwhile, the path corner profile, material removal rate, material removal depth, and surface roughness were analyzed. A series of single-factor experiments were performed to verify the feasibility of the proposed method. The experimental results indicate that a better grating corner profile and a higher material removal rate can be obtained with ultrasonic vibration. The introduction of polishing oblique angle can significantly improve the accuracy of grating corner profile and material removal rate calculation. This paper can provide useful insight and guidance to facilitate high-efficiency and high-precision machining of grating structures.

Selective adsorption of Hg(ii) with diatomite-based mesoporous materials functionalized by pyrrole-thiophene copolymers: condition optimization, application and mechanism.

A novel diatomite-based mesoporous material of MCM-41/co-(PPy-Tp) was prepared with MCM-41 as carrier and functionalized with the copolymer of pyrrole and thiophene. The physicochemical characteristics of the as-prepared materials were characterized by various characterization means. The removal behaviour of Hg(ii) was adequately investigated via series of single factor experiments and some vital influence factors were optimized via response surface methodology method. The results exhibit that diatomite-based materials MCM-41/co-(PPy-Tp) has an optimal adsorption capability of 537.15 mg g-1 towards Hg(ii) at pH = 7.1. The removal process of Hg(ii) onto MCM-41/co-(PPy-Tp) is controlled by monolayer chemisorption based on the fitting results of pseudo-second-order kinetic and Langmuir models. In addition, the adsorption of Hg(ii) ions onto MCM-41/co-(PPy-Tp) is mainly completed through forming a stable complex with N or S atoms in MCM-41/co-(PPy-Tp) by electrostatic attraction and chelation. The as-developed MCM-41/co-(PPy-Tp) displays excellent recyclability and stabilization, has obviously selective adsorption for Hg(ii) in the treatment of actual electroplating wastewater. Diatomite-based mesoporous material functionalized by the copolymer of pyrrole and thiophene exhibits promising application prospect.

Determination of organophosphorus pesticides based on graphene oxide aerogel solid phase extraction column

以氧化石墨烯气凝胶三维纳米材料作为固相萃取的吸附剂,结合高效液相色谱,对食品中的有机磷农药(辛硫磷、双硫磷、倍硫磷、杀螟硫磷)进行检测分析。首先,利用冷冻干燥的方式制备得到氧化石墨烯气凝胶,通过扫描电镜、红外光谱、比表面积吸附等一系列的实验手段对其形貌及物理特性进行了表征,证明其成功合成。从扫描电镜中可见石墨烯的层状褶皱结构,其表面积为740.51 m2/g。然后,将氧化石墨烯气凝胶直接填充于固相萃取柱中,在未借助任何硅胶等基体的条件下进行萃取研究;通过单因素实验,系统研究了萃取和洗脱条件对有机磷农药萃取回收率的影响。结果显示,在上样体积15 mL、样品溶液pH值4、上样速率1.0 mL/min、洗脱剂1.0 mL乙腈的条件下萃取回收率最高。与商用的萃取材料进行比较,包括碳十八硅胶柱(C18)、阴离子交换柱(SAX)、氨基柱(-NH2)和硅酸镁柱(Florisil),氧化石墨烯气凝胶填充的固相萃取柱的萃取回收率有明显提高。实验考察了氧化石墨烯气凝胶直接填充的萃取柱的寿命,结果显示该萃取柱可以重复使用15次,可见解决了分散无基体支撑的石墨烯纳米片容易破碎、堵塞筛板的问题。与液相色谱联用建立分析方法,4种有机磷农药的线性范围较宽,辛硫磷、双硫磷和倍硫磷的线性范围为1~200 μg/L,杀螟硫磷的线性范围为2~200 μg/L,线性拟合良好(线性相关系数r2≥0.9949),检出限为0.2~0.5 μg/L,满足于我国和其他国家限定标准的检测。将该方法应用于实际样品,在苹果皮中未检测到有机磷农药,对其进行加标,回收率为70.5%~93.6%,相对标准偏差≤10.4%。

Experimental study on designing optimal vibration amplitude in ultrasonic assisted incremental forming of AA6061-T6

Superimposing ultrasonic vibration with metal working process has been proven as effective auxiliary method for improving the quality characteristics. Since, the incremental forming is a state-of-the-art sheet metal working process, number of researches which applied ultrasonic vibration to this process are limited and further studies are still required to basically understand its influence on performance measures. In the present study, an experimental attempt was made to understand how the vibration amplitude influences the forming force, thickness distribution and dimensional accuracy of the samples formed by incremental forming process. In order to do so, series of single factor experiments were designed by variation of vibration amplitude (0, 5, 10 and 15 µm) as main parameter and other parameters were kept constant. The obtained results revealed that increasing the vibration amplitude up to a certain value results in reduction of forming force and dimensional deviation, as well it results in thinning in critical region. At the end of the work, an optimization framework was designed to find interaction effect of process factors with achieving regarding minimized process time as well desired sample quality. It is found from optimization results that superimposing high vibration amplitude provides condition for obtaining minimum process time as well desired quality characteristic of workpiece.

Effect of Acid Treatment on the Catalytic Activity and Mechanical Stability of SmMnO3/Cordierite Monolithic Catalysts

AbstractSmMnO3/cordierite monolithic catalysts were synthesized by a modified citric acid method and treated with dilute HNO3, which was used to explore the effect of acid treatment on the catalytic performance and mechanical stability of the monolithic catalysts. Firstly, acid treatment can significantly improve catalytic activity of catalyst in o‐xylene oxidation, which is attributed to the increase of the specific surface area of the catalyst and the change of surface oxygen species. A series of single factor experiments show that the SmMnO3/cordierite monolithic catalyst treated by 1.0 mol/L HNO3 for 6 h and calcined at 450 °C for 1 h has the best performance. Furthermore, the mechanical stability of the catalysts treated by dilute HNO3 was tested, which show that too long acid treatment time and too high acid concentration will reduce the mechanical stability of the catalyst and 1.0 mol/L HNO3 treatment for 1 h is the best. Different calcination temperature and calcination time will also affect the mechanical stability of the catalyst. Finally, the catalyst has good stability of catalytic performance and mechanical stability.

Performance evaluation of porous gas channel ribs in a polymer electrolyte fuel cell

Commercialization of hydrogen fuel cells is scaling at an unprecedented rate. As a result, developers are focused on stack manufacturability and the associated challenges to scaling-up an assembly with thousands of individual parts that have strict dimensional tolerances. This paper first proposes a fuel cell architecture designed for continuous manufacturing that could result in all components of a stack being contained in a rolled good. This concept would move the reactant gas distribution channels into the gas diffusion substrate. The performance of the porous ribs that would result from this concept is compared with a conventional solid rib flow distributor. Performance and cell resistance are presented in a series of single factor experiments that investigate a wide PEMFC operating space. The results show that a porous rib cathode flow field is feasible, with performance benefits at near- and over-saturated operating conditions.

Feasibility of fly ash as fluxing agent in mid- and low-grade phosphate rock carbothermal reduction and its reaction kinetics

Abstract The feasibility of industrial waste fly ash as an alternative fluxing agent for silica in carbothermal reduction of medium-low-grade phosphate ore was studied in this paper. With a series of single-factor experiments, the reduction rate of phosphate rock under different reaction temperature, reaction time, particle size, carbon excess coefficient, and silicon–calcium molar ratio was investigated with silica and fly ash as fluxing agents. Higher reduction rates were obtained with fly ash fluxing instead of silica. The optimal conditions were derived as: reaction temperature 1,300°C, reaction time 75 min, particle size 48–75 µm, carbon excess coefficient 1.2, and silicon–calcium molar ratio 1.2. The optimized process condition was verified with other two different phosphate rocks and it was proved universally. The apparent kinetics analyses demonstrated that the activation energy of fly ash fluxing is reduced by 31.57 kJ/mol as compared with that of silica. The mechanism of better fluxing effect by fly ash may be ascribed to the fact that the products formed within fly ash increase the amount of liquid phase in the reaction system and promote reduction reaction. Preliminary feasibility about the recycling of industrial waste fly ash in thermal phosphoric acid industry was elucidated in the paper.

Preparation and performance evaluation of polyvinyl alcohol grafted polyacrylic acid for plugging

Well-leakage is a very difficult problem in the process of drilling at home and abroad. At present, it mainly relies on the cumulative effect of plugging slurry to implement plugging regardless of the number of times and costs. Commonly used plugging slurry and plugging technology are difficult to guarantee the success rate and scientific of plugging malignant leakage, which has an extremely bad impact on the development of the petroleum industry. In this study, With polyvinyl alcohol and acrylic acid as main agents, a plugging material of acrylic acid grafted polyvinyl alcohol was prepared, and the influence of the composition of the reaction system on the gel state of the system was studied. Through a series of singlefactor experiments, the best formula for preparing the plugging material was determined, polyvinyl alcohol and acrylic acid (specific gravity 1:3) + crosslinking agent (0.1wt%) + initiator (0.3wt%). The gel plugging agent using above formula to prepare has good gel strength and suitable gel time, and has a good application prospect in solving the problem of lost circulation.

Hierarchical Flower-Like Hollow SiO2@TiO2 Spheres with Enhanced Thermal Insulation and Ultraviolet Resistance Performances for Building Coating.

In this paper, a novel 3D hierarchical flower-like hollow SiO2@TiO2 sphere (FHST) with a large number of irregular nanosheets was successfully prepared by a solvothermal method and subsequent calcination process, in which multiple different functional components were perfectly integrated into a single nanostructure. The morphology and structure of FHSTs were characterized by SEM, TEM, XRD, XPS, and BET. The growth mechanism of the 3D flower-like structure was obtained through a series of single-factor experiments, of which hexamethylenetetramine acted in a vital role. Moreover, it was also used as a filler for polyacrylate substrate to improve the thermal insulation and ultraviolet resistance properties of architectural coatings. The results showed that the composite film with FHSTs had lower thermal conductivity and higher light reflection performance compared to those with hollow SiO2 spheres, hollow TiO2 spheres, and hollow SiO2@TiO2 spheres. More significantly, its transmittance at the full wavelength of ultraviolet light was almost zero, exhibiting a prominent inhibitory effect on UVA. In addition, compared with commercially available hollow glass microspheres, FHSTs had more excellent thermal insulation performance in practical applications.