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Titanium alloy with high corrosion resistance, high strength-to-density ratio, and excellent biocompatibility has a wide range of applications in the field of biomedical implants. Polishing experiments of titanium alloy with a small size and complex shapes were investigated using an ultrasonic assisted magnetorheological finishing (UMRF) device excited by a three-pole magnetic field generator. The models of the normal force and the shear force were first proposed based on the Preston equation to analyze the mechanism of material removal in the UMRF process. Subsequently, the single-factor experiments using titanium alloy nuts (M3) and the MR polishing fluid with silicon carbide abrasives were carried out. Furthermore, to improve the surface roughness and the change rate of surface roughness of nuts, orthogonal tests with a standard L9(34) orthogonal array were designed and performed based on the optimized process parameters obtained from the single-factor experiment. The results indicated the effect on surface roughness and change rate of surface roughness as applied current > roller speed > ultrasonic amplitude > spindle speed and applied current > roller speed > spindle speed > ultrasonic amplitude, respectively. Moreover, the surface roughness was improved from an initial 1.247 μm to a final 0.104 μm after the polishing for 80 min under these optimal process parameters. [ABSTRACT FROM AUTHOR]

Abstract Titanium alloy with high corrosion resistance, high strength-to-density ratio, and excellent biocompatibility has a wide range of applications in the field of biomedical implants. Polishing experiments of titanium alloy with a small size and complex shapes were investigated using an ultrasonic assisted magnetorheological finishing (UMRF) device excited by a three-pole magnetic field generator. The models of the normal force and the shear force were first proposed based on the Preston equation to analyze the mechanism of material removal in the UMRF process. Subsequently, the single-factor experiments using titanium alloy nuts (M3) and the MR polishing fluid with silicon carbide abrasives were carried out. Furthermore, to improve the surface roughness and the change rate of surface roughness of nuts, orthogonal tests with a standard L9(34) orthogonal array were designed and performed based on the optimized process parameters obtained from the single-factor experiment. The results indicated the effect on surface roughness and change rate of surface roughness as applied current > roller speed > ultrasonic amplitude > spindle speed and applied current > roller speed > spindle speed > ultrasonic amplitude, respectively. Moreover, the surface roughness was improved from an initial 1.247 μm to a final 0.104 μm after the polishing for 80 min under these optimal process parameters.

The climbing of trees to pick pinecones is a high-risk exercise. In this study, a mechanical gripper jaw was designed. Frictional characteristics between the pinecones and the mechanical gripper jaw during pinecone picking under different conditions were investigated using a workbench simulation, homemade inclined friction meter, and mass tester. Three-level orthogonal and one-factor tests were conducted. The relationship between the water content and friction properties and between the water content and hardness were investigated, and conclusions were drawn on how water content affected friction properties by influencing hardness. The results showed that the contact material greatly affected the friction properties. The pinecone water content was maintained between 24% and 28% to ensure that the coefficient of friction was maximized and that the pinecones were sufficiently hard to dislodge. Additionally, a prototype machine was used to perform pinecone-gripping experiments to validate the experimental and simulation results. Consequently, the results of this study provide a useful reference for the structural design of pinecone picking robots and the picking reason.

The climbing of trees to pick pinecones is a high-risk exercise. In this study, a mechanical gripper jaw was designed. Frictional characteristics between the pinecones and the mechanical gripper jaw during pinecone picking under different conditions were investigated using a workbench simulation, homemade inclined friction meter, and mass tester. Three-level orthogonal and one-factor tests were conducted. The relationship between the water content and friction properties and between the water content and hardness were investigated, and conclusions were drawn on how water content affected friction properties by influencing hardness. The results showed that the contact material greatly affected the friction properties. The pinecone water content was maintained between 24% and 28% to ensure that the coefficient of friction was maximized and that the pinecones were sufficiently hard to dislodge. Additionally, a prototype machine was used to perform pinecone-gripping experiments to validate the experimental and simulation results. Consequently, the results of this study provide a useful reference for the structural design of pinecone picking robots and the picking reason. [ABSTRACT FROM AUTHOR]

To effectively resolve the inherent conflict between dust control and ice prevention on truck roads during North Surface Coal Mine winters, initially, via monomer preference experiments, the optimal monomers for wetting, moisturizing, and condensing functions were identified as sodium dodecylbenzene sulfonate (B), glycerol (N), and polyacrylamide (R). In parallel, through compound synergistic experiments, the constituent elements of an anti-freezing agent were determined, referred to as F. Subsequently, a four-factor three-level orthogonal test was conducted employing the monomers B, N, R, and the anti-freezing agent F. This evaluation focused on four principal control parameters: penetration rate, evaporation resistance, viscosity, and freezing point. The results led to the identification of the optimal antifreeze and dust suppressant formulation, designated as B2N3R1F3. Within the North Open-Pit Coal Mine, the self-developed dust suppressant was applied to the field test section. Multiple parameters were examined for 6 consecutive days, encompassing the water content of the pavement geotechnical soil, the concentrations of total dust and exhaled dust, and the particle size distribution of dust within this road section. The field test results show that: the average water content of the road surface within the dust suppressant test section measured at 12%; the dust reduction efficiency of total dust and exhaled dust is 93% and 91%; the proportion of dust particles with a size exceeding 500 μm increased by 54.6%. These comprehensive findings provide a empirical framework for the effective resolution of the practical challenge of simultaneously managing dust control and frost protection on truck roads within surface coal mines. [ABSTRACT FROM AUTHOR]

Abstract The strength of the backfill is crucial for safe and efficient mining, and the cementing material is the key to obtaining a strong backfill. In this paper, industrial waste was used as a raw material, into which basis basalt fibres of different lengths and dosages were incorporated. First, the influencing factors were determined through orthogonal test designs. The optimal ratio of solid–liquid ratio of 2 and basalt fiber content of 2% and length of 6 mm was obtained, and thereby the complete proportion of the backfill material was obtained. The compressive strength and slump of the backfill material mixed with basalt fibres were investigated, and the interfacial mechanism of the backfill material was analysed at the microscopic level using scanning electron microscopy and X-ray diffraction. The results indicated that the degrees of influence of the different factors on the mechanical properties of the backfill material decreased in the following order: Solid–liquid ratio > fibre dosage > fibre length. Furthermore, there were different degrees of interaction among them. Under the best test proportion, that is, when the Solid–liquid ratio was 2, the fibre dosage was 2%, and the fibre length was 6 mm, the slump was 210 mm, and the compressive strength was 5.03 MPa. The mechanical properties were the best at this time. Through data regression, the relationship between the fibre dosage and the average peak stress was established, and the full curve expression for the uniaxial compressive stress–strain of the BFGF specimen was obtained. According to a microscopic characterisation analysis, the slag formed C–S–H gel, which contributed to the early-stage strength of the filling material; fly ash and coal gangue contained a large amount of aluminium, which formed hydrated aluminosilicate with a framework structure, and this contributed significantly to the later-stage strength of the backfill material. The addition of basalt fibres reduces the internal defects of the backfill, allowing the internal pore structure of the backfill to be optimised and the compressive strength to be increased. The results of this study have been successfully implemented in actual projects. Additionally, they provide a reference for similar mine management projects and have considerable promotion and application value.

In response to the problems of low efficiency and difficulty of pruning operations in modern dwarf dense orchards, an adjustable position saw blade pruning machine was designed, mainly consisting of a pruning device, a regulating device and a hydraulic system. Through the mechanical and modal analysis of the circular saw blade, the limit speed of the circular saw blade was derived. A finite element model of the sawing process was established, and a single-factor simulation analysis was conducted for three important parameters: feed rate, circular saw blade speed and branch diameter, and a three-factor, three-level quadratic regression orthogonal test was designed to derive the best matching sawing parameters, which was verified in field tests. The test results showed that the average passing rate was 92.8% at the feed rate of 4 km/h under the circular saw blade speed of 2800 rpm, which was higher than 88.8% at 3 km/h and 88.9% at 5 km/h. The optimum sawing parameters were: the circular saw blade speed of 2800 rpm and feed rate of 4 km/h, which were consistent with the simulation results, and the passing rate of the cut was high at this time, meeting the technical requirements of orchard pruning. [ABSTRACT FROM AUTHOR]

Purposes This work is conducted to achieve the objectives of carbon emission reduction and resource utilization of solid waste. Methods Geopolymer concrete was prepared from red mud and coal-metakaolin, and the effect of four factors on its mechanical properties was investigated with an orthogonal test method. Findings The water-binder ratio was found to have a significant effect on the strength of the geopolymer concrete, followed by Na2O/H2O, while the curing conditions and the aggregate-binder ratio have lesser effect, according to the ANOVA. On the basis of the experimental results, the mathematical model of compressive strength and splitting tensile strength of geopolymer concrete was established, and the fitting effects of the equations were favourable. Further analysis obtained the optimal ratio of geopolymer concrete, and the compressive strength and splitting tensile strengthes of the cube specimens cured for 28 d were 43.6 MPa and 2.87 MPa, respectively. Then, the pore structures of the geopolymer concretes with different W/B ratios were characterised with low-field NMR tests. The results indicate that the geopolymer concrete is predominantly microporous internally. The increased content of evaporable free water increases the porosity and coarsens the pore structure, which macroscopically manifests as a reduction in strength of the material. This study can provide some theoretical guidance for the promotion and engineering application of geopolymer concrete.

Rib spalling is one of the main factors restricting the safe and efficient production of the fully mechanized mining face in gangue-bearing coal seams, and the gangue has significant influence on the occurrence of rib spalling. In this study, the instability process and mechanical mechanism of rib spalling in gangue-bearing coal seams were studied, and the sensitivity of gangue parameters to rib spalling was analyzed. The simulation test of rib spalling under different gangue parameters was carried out by orthogonal tests. The width and depth of rib spalling were taken as evaluation indexes, and the influence of gangue parameters on the rib spalling was analyzed by variance analysis and significance tests. The results show that the failure process of rib spalling is characterized by the fracturing failure of the lower coal body, shear failure of the gangue layer, and the falling off of the upper coal body caused by the gravity; the gangue parameters (thickness, density, joint inclination, and internal friction angle) have an important influence on the sliding instability of the coal wall. In the sensitivity analysis, the influence of gangue parameters on the width of rib spalling is ordered as gangue density > joint inclination > gangue thickness > internal friction angle; the influence of gangue parameters on the depth of rib spalling is ordered as gangue density > joint inclination > internal friction angle > gangue thickness. Besides, the greater the gangue density, the less damage caused by stress concentration, and the lower the risk of rib spalling. [ABSTRACT FROM AUTHOR]

Flax is an economically important fiber crop, however, it requires degumming to yield usable fibers. The degumming process of flax roving is a key step in flax processing and production. In this study, deep eutectic solvent (DES; choline chloride–urea) pretreatment was combined with microbial treatment to develop an ecofriendly and effective degumming method for flax roving. The optimal conditions for DES pretreatment (100°C for 120 min with 90% DES) were obtained through orthogonal tests. DES combine microbial treatment could effectively remove gum from the flax fibers. The flax roving fibers were characterized by chemical analyses, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and thermogravimetric analysis. Compared with fibers treated with microbes alone, flax roving fibers subjected to DES combine microbial treatment showed better breaking tenacity (16.77 cN/tex) and average pectin, hemicellulose, and lignin removal rates of approximately 86.4%, 26.7%, and 55.1%, respectively. NMR revealed that the composition of DES was not damaged during pretreatment, which means the bulk solution could be reused. This research showed that DES combine microbial treatment is feasible and effective method for flax roving degumming.

Previous research(Yu et al. [25]) found that choline chloride-urea DES pretreatment could dissolve the hemicelluloses of ramie fibers, while choline chloride-oxalic acid dehydrate DES pretreatment could significantly enhance the nanofibrillation of the recycled fibers. Given the limited literature on DES degumming for flax roving, the effect of treatment temperature, treatment time, liquor ratio, and DES concentration on the DES pretreatment was investigated using orthogonal tests. Keywords: Flax roving; deep eutectic solvent; microbial degumming; Bacillus subtilis; orthogonal tests; gum; ; ; ; ; ; EN Flax roving deep eutectic solvent microbial degumming Bacillus subtilis orthogonal tests gum ZH 9410 9419 10 11/21/22 20221220 NES 221220 Introduction Flax, a traditional cellulosic fiber plant, is widely used in the textile, medical, and composite industries, and an important commercial crop in Europe(Pandey et al. [12]). The flax fibers obtained after DES pretreatment and microbial treatment were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and X-ray diffractometry (XRD). [Extracted from the article]

Volatile halogenated hydrocarbons (VHCs) attracted many attentions due to its toxicity and persistence in the environment. In this research, a novel in situ ecological restoration reactor was applied to the degradation of VHCs in polluted river water. The optimized working condition adaptation of the in situ restoration technique was evaluated through orthogonal tests. The experiments showed that when the water depth was 0.4 m, the HRT was 5 days, and the current velocity was 1 m/s, the optimal removal efficiency of VHCs in the reactor was achieved. And the removal rates of CHCl3, CCl4, C2HCl3, and C2Cl4 reached 70.27%, 70.59%, 67.74%, and 81.82%, respectively. The results showed that both HRT and water depth were significantly related to the removal efficiency of reactor. The physiological state of the plants was analyzed by fitting rapid light curve (RLC) model, which showed that the accumulation of VHCs inhibited the photosynthetic performance of plants. Moreover, the microbial community structures of fillers were tested by high-throughput sequencing, and the findings supported that the microbial community made a great response to adapt to the changes in environment of the reactor. The relative abundance of Rhodocyclaceae increased slightly, which hinted that it had good adaptability to VHCs in polluted river water. The research results confirmed that in situ ecological restoration reactor was a potential approach for removal VHCs in polluted river water. [ABSTRACT FROM AUTHOR]

In this study, the effects of coal blending ratio, pyrolysis temperature, pyrolysis atmosphere and coal particle size on the quality of pyrolyzed char were investigated via a combination of orthogonal experimental design and grey relational analysis. Coal-XG and Coal-LL were pyrolyzed under various conditions to produce chars which were characterized to ascertain their properties such as chemical structure and reactivity. The results indicated that the pyrolysis temperature has the most significant impact on the quality of the char, followed by the pyrolysis atmosphere, coal blending ratio and coal particle size. The increase in pyrolysis temperature not only diminished char yield but also accelerated the consumption of oxygen-containing functional groups and the polycondensation of small aromatic ring structures throughout the reaction process. This led to a reduction in the reactivity of pyrolyzed char and the establishment of a more ordered structure. Meanwhile, the involvement of CO 2 and H 2 O prevented the condensation of small aromatic rings and fostered the generation of additional oxygen-containing functional groups, which resulted in lower yield and higher reactivity of the char under these two atmospheres. Through systematic analysis, only the Raman characteristic parameter I (Gr+VL+Vr) /I D exhibited a strong positive linear correlation with char reactivity, making it a reliable indicator for characterizing the reactivity of char. • The orthogonal design was used to study four response factors. • GRA was used to find optimal conditions and impact ranking of different factors. • Linear regression was applied to relate Raman/FTIR parameters to reactivity. • Blend experiments were conducted with two coking coals. [ABSTRACT FROM AUTHOR]

The synthetic jet piezoelectric air pump is a potential miniature device for electronic cooling. In order to improve the performance of the device, a small-sized synthetic jet piezoelectric air pump is proposed in this work, which is mainly characterized by petal-shaped inlet channels. First, the structure and working principle of the piezoelectric vibrator and the proposed pump are analyzed. Then, three synthetic jet piezoelectric air pumps with different inlet channels are compared. These inlets are the direct channels, the diffuser/nozzle channels, and the petal-shaped channels, respectively. Furthermore, the performance of the synthetic jet piezoelectric air pump with the petal-shaped inlet channels is optimized by orthogonal tests. Finally, the simulation was used to investigate the heat dissipation capability of the synthetic jet piezoelectric pump. The experimental results show that among the three inlet channels, the petal-shaped channel can greatly improve the performance of the pump. The unoptimized pump with petal-shaped channels has a maximum flow rate of 1.8929 L/min at 100 V, 3.9 kHz. Additionally, the optimized pump with petal-shaped channels reaches a maximum flow rate of 3.0088 L/min at 100 V, 3.7 kHz, which is 58.95% higher than the unoptimized one. The proposed synthetic jet piezoelectric air pump greatly improves the output performance and has the advantages of simple structure, low cost, and easy integration. The convective heat transfer coefficient of the synthetic jet piezoelectric pump is 28.8 W / (m 2 · ° C) , which can prove that the device has a better heat dissipation capability. [ABSTRACT FROM AUTHOR]

The tribological properties of SnO2 nanofluids were investigated using ball-on-plate reciprocating sliding wear tests. It was found that the coefficient of friction was reduced by 34.9% using 3 wt% SnO2 nanoparticles. The wear width and wear depth were reduced by 42% and 50.1%, respectively, using 2 wt% SnO2 nanoparticles. In the orthogonal tests, the frequency had the greatest influence on the friction and wear loss. Additionally, the optimal working conditions were a normal load of 50 N, a motion frequency of 1 Hz, and a surface roughness of 500–600 nm. Additionally, the excellent tribological performance of SnO2 nanofluids could be attributed to the formation of a tribo-film with a low shearing resistance due to the oleic acid and a protective layer due to the embedment of SnO2 nanoparticles. [ABSTRACT FROM AUTHOR]

DEFORM-3D software was used to simulate the forging process with liquid core. Three orthogonal tests were designed to obtain the results with solid-phase thickness, reduction amount and pressing speed as three factors. The significant factors were acquired by the range analysis which affected the values of the equivalent strain and the equivalent stress in the solid-phase region, the solid–liquid two-phase region and the liquid-phase region. We mastered the deformation law during the forging process with liquid core. Four groups of the physical models of the multilayer gradient were also established under laboratory conditions. Fifty-three sets of forging parameters data were recorded including the solid-phase thickness, the reduction amount, the pressing speed and the forming pressure in each group. We constructed the relationship equation between the forming pressure and the other three factors in Origin. The equation provided a theoretical basis for selecting the press tonnage during the forging process with liquid core. [ABSTRACT FROM AUTHOR]

The synthetic jet piezoelectric air pump is a potential miniature device for electronic cooling. In order to improve the performance of the device, a small-sized synthetic jet piezoelectric air pump is proposed in this work, which is mainly characterized by petal-shaped inlet channels. First, the structure and working principle of the piezoelectric vibrator and the proposed pump are analyzed. Then, three synthetic jet piezoelectric air pumps with different inlet channels are compared. These inlets are the direct channels, the diffuser/nozzle channels, and the petal-shaped channels, respectively. Furthermore, the performance of the synthetic jet piezoelectric air pump with the petal-shaped inlet channels is optimized by orthogonal tests. Finally, the simulation was used to investigate the heat dissipation capability of the synthetic jet piezoelectric pump. The experimental results show that among the three inlet channels, the petal-shaped channel can greatly improve the performance of the pump. The unoptimized pump with petal-shaped channels has a maximum flow rate of 1.8929 L/min at 100 V, 3.9 kHz. Additionally, the optimized pump with petal-shaped channels reaches a maximum flow rate of 3.0088 L/min at 100 V, 3.7 kHz, which is 58.95% higher than the unoptimized one. The proposed synthetic jet piezoelectric air pump greatly improves the output performance and has the advantages of simple structure, low cost, and easy integration. The convective heat transfer coefficient of the synthetic jet piezoelectric pump is 28.8 W/(m2·°C), which can prove that the device has a better heat dissipation capability.

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Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Climate change necessitates research into interactions between elevated carbon dioxide (CO2) concentrations and drought on plant photosynthetic physiology. This study describes the physiological properties of Platycladus orientalis (Chinese thuja) and Quercus variabilis (Chinese cork oak) saplings cultivated through orthogonal treatments of four CO2 concentrations combined with five soil volumetric water contents (SWC). It highlights the differences between the interactive effects from the treatments. Water stress had little effect on photosynthetic traits until the soil volumetric water contents exceeded 70–80 or 100%. Similar variations in carbon-13 isotope abundance (δ13C) of water soluble compounds (δ13CWSC) extracted from leaves of two species have been observed. Whether soil volumetric water contents exceeded or fell below the water threshold values (70–80% of field capacity for P. orientalis and 100% of field capacity for Q. variabilis), instantaneous water use efficiency decreased. Elevated carbon dioxide could increase iWUE and enhance drought tolerance, depending on stimulating net photosynthetic rates and declining stomatal conductance and transpiration rates. Augmenting either drought, excess water, or ambient carbon dioxide could alleviate the physiological inhibition caused by the stresses described above. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking soil layer 7 undisturbed fine sand layer in Shanghai as the test object, using GDS triaxial test apparatus, we carried out the orthogonal tests of 4 factors and 3 levels repeated pumping and recharging to explore the deformation characteristics of fine sand in dewatering. The strain and stress characteristics of single sample were discussed under the effect of dewatering and the orthogonal analysis of the nine samples were also conducted. It was revealed that axis strain of fine sand includes elastics, main consolidation and second consolidation, while the radius strain shows the up and down and increases constantly as the repeated pumping and recharging. And the water level drawdown has the greatest effect on the deformation characteristics of fine sand, and the intermittent time and recharging speed are moderate and nearly the same, and the precipitation speed is the least significant. The deformation mechanism of fine sand is closely related to its single grain microstructure. Finally the validity analysis of the orthogonal test shows the consistency and effectiveness of the test results. The research conclusion can provide technical guidance and theoretical basis for controlling ground settlement induced by dewatering in deep foundation pit engineering. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes an experimental investigation into the compaction characteristics of cement-stabilized macadam base materials (CSMBM) in a saline soil area. Through the field tests, the main causes of arch expansion in an existing road were analyzed. Based on this, the compaction tests and microscopic tests were designed to analyze the impacts of temperature, sodium sulfate content and cement content on the compaction characteristics of CSMBM. Then, the orthogonal test was designed to analyze the effects of the degree of the temperature, the cement content, and the sodium sulfate content on the compaction results of the CSMBM. Feld tests results show that the temperature, sodium sulfate content and cement content may be the main causes of arch expansion. The compaction tests show that with the temperature increasing, the optimal water content (OWC) decreases, but the maximum dry density (MDD) increases; with the sodium sulfate content increasing, the OWC increases, but the MDD decreases; with the cement content increasing, both MDD and OWC increase. The microscopic tests show that the increase of temperature and cement content is beneficial to the compactness between cementitious materials and aggregates, while the increase of sodium sulfate content makes the whole structure of cementitious materials and aggregates increasingly rough. The orthogonal test shows that the temperature has the greatest influence on the MMD, and the sodium sulfate content has the greatest influence on the OWC. Thus, in a sulfate saline soil area, the construction temperature, the sodium sulfate content and the cement content should be controlled to ensure the compaction quality of CSMBM.

Enzymatic hydrolysate of poplar wood was used in this study to produce biobutanol by a mutant M-18. Plackett-Burman and Box-Behnken designs were adopted in order to screen crucial factors from various nutrient factors affecting butanol production. These factors included reducing sugar content of hydrolysate, MgSO4•7H2O, yeast extract, K2HPO4, FeSO4•7H2O, CaCO3, and ammonium sulfate. The results demonstrated that a reduction in sugar content, K2HPO4, and CaCO3 were the most critical factors. Yeast extract was also found to have a significant effect on biobutanol production by performing an analysis of variance (ANOVA). Optimal variables were 44.53 g/L of reducing sugar concentration, 1.36 g/L of K2HPO4, and 4.65 g/L of CaCO3 according to the Box-Behnken design. A model was established and used to predict a maximum biobutanol production of 7.59 g/L. Optimal conditions of fermentation were determined by orthogonal tests. Three distinct factors with important effects on biobutanol production were explored. The pH was identified as having the most significant effect on biobutanol biosynthesis. Optimized fermentation conditions for biobutanol production were determined at an initial pH of 6.5, temperature 36 °C, and inoculum quantity 9%. Under these conditions, a maximum biobutanol production of 8.41±0.20 g/L was achieved in verification experiments in a 3 L fermentation tank.

The hyporheic zone is a transition zone for the exchange of matter and energy between surface water and subsurface water. The study of trends and sensitivities of bed hyporheic exchanges to the various influencing factors is of great significance. The surface−groundwater flow process was simulated using a multiphysics computational fluid dynamics (CFD) method and compared to previous flume experiments. Based on that, the single-factor effects of flow velocity (u), water depth (H), dune wave height (h), and bed substrate permeability (κ) on hyporheic exchange in the bed hyporheic zone were investigated. The sensitivity analysis of various factors (H, u, dune wavelength (L), h, bed substrate porosity (θ), κ, and the diffusion coefficient of solute molecules (Dm)) in the surface−subsurface water coupling model was done using orthogonal tests. The results indicated that u, h, and κ were positively related, whereas H was negatively related to hyporheic exchange. H and u showed large effects, whereas κ, Dm, and θ had moderate effects, and L and h showed small effects on hyporheic exchange. This study provides valuable references for the protection and recovery of river ecology.

Internal erosion at soil–structure interfaces is a dangerous failure pattern in earth-fill water-retaining structures. However, existing studies concentrate on the investigations of internal erosion by assuming homogeneous materials, while ignoring the vulnerable soil–structure-interface internal erosion in realistic cases. Therefore, orthogonal and single-factor tests are carried out with a newly designed apparatus to investigate the critical hydraulic gradient of internal erosion on soil–structure interfaces. The main conclusions can be draw as follows: (1) the impact order of the three factors is: degree of compaction > roughness > clay content; (2) the critical hydraulic gradient increases as the degree of compaction and clay content increases. This effect is found to be more obvious in the higher range of the degree of soil compaction and clay content. However, there exists an optimum interface roughness making the antiseepage strength at the interface reach a maximum; (3) the evolution of the interface internal erosion develops from inside to outside along the interface, and the soil particles at the interface flow as a whole; and (4) the critical hydraulic gradient of interface internal erosion is related to the shear strength at the interface and the severity and porosity of the soil.

Effects of three important operating conditions (liquid flow rate, gas flow rate and regeneration temperature) on the CO 2 capture and mass transfer performance of the absorption of CO 2 into a hybrid solvent MEA–Methanol were studied in a pilot-plant absorber packed with three different packings consisting of Sulzer BX500, Mellapale Y500 and Pall rings 16 × 16 through orthogonal tests. CO 2 absorption experiment was conducted under the optimal operating parameters of three packings achieved from the orthogonal experiments (liquid flow rate 30 l/h, flue gas flow rate 3 m 3 /h and regeneration temperature 74 °C for Mellapale packing 500Y, liquid flow rate 40 l/h, flue gas flow rate 3 m 3 /h and regeneration temperature 74 °C for Pall rings packing 16 × 16 and liquid flow rate 40 l/h, flue gas flow rate 5 m 3 /h and regeneration temperature 74 °C for Sulzer packing BX500). The results showed that regeneration temperature was the most important factor affecting the CO 2 capture efficiency and gas flow rate had little effect on the CO 2 capture efficiency. In addition, the optimal operating conditions of the three packings were achieved in this study and Sulzer BX500 packing had the best mass transfer performance. [ABSTRACT FROM AUTHOR]

The present work reported tests of a new solvent 30 wt% MEA-Methanol compared to aqueous 30 wt% MEA solvent in a pilot-plant test bed, which comprises the complete absorption/desorption. The two solvents were studied in the same way in the test bed and detailed results were reported for both solvents. The measurements were carried out at a constant CO 2 removal rate of 90% by an adjustment of the regeneration energy in the desorber for systematically varied L/G ratios, flue gas flow rate and absorber height. Results from these studies indicated that MEA-Methanol solvent had a faster CO 2 absorption rate and a lower regeneration energy consumption compared to aqueous MEA solvent. Regeneration heat duty (Q reg ) of MEA-Methanol solvent at optimum operating conditions was obviously lower than that of aqueous MEA solvent (3.22 MJ/kg CO 2 and 4.04 MJ/kg CO 2 , respectively), which showed that MEA-Methanol had a potential to replace aqueous MEA solvent in industrial CO 2 pilot plant. [ABSTRACT FROM AUTHOR]

Effects of three important operating conditions (rich solvent flow rate, rich solvent loading and regeneration temperature) on the regeneration performance of the desorption of CO 2 from a hybrid solvent MEA-Methanol were studied in a pilot-plant stripper packed with three different packing consist of Sulzer BX500, mellapale 500Y and Pall rings 16 × 16 through the orthogonal tests. The results showed that regeneration temperature was the most important factor affected the CO 2 cyclic capacity Δ ɑ and the solvent flow rate was the most important factor affected the regeneration heat duty Q reg . And the optimal operating conditions under three packing were as follows: rich solvent flow rate = 30 L/h, the rich solvent loading = 0.5 mol CO 2 /mol amine and the regeneration temperature affected Δ ɑ and Q reg greatly, a higher regeneration temperature caused a bigger Δ ɑ and a higher Q reg . In addition, the regeneration performance of Sulzer packing BX500 was the best and that of Pall rings packing 16 × 16 was the worst achieved in this study. [ABSTRACT FROM AUTHOR]

• Material removal modeling of cylindrical polishing considering multi-scale contact. • Surface roughness modeling by Hertz contact, G-W model and single grain cutting. • Taguchi orthogonal experiments, ANOVA and level average response analysis. • Discussion of contact area, contact gap, single grain's cutting depth. • Investigation on influences of loading force and grain size at multi-scale. In this paper, the material removal and the surface roughness in the cylindrical polishing with a soft pad and free abrasives are investigated theoretically and experimentally. Existing our studies have suggested that there is different contact deformation at dimension scales of millimeter, micrometer and nanometer. On that basis, the material removal model is proposed by integrating the contact at different scales in accordance with the Hertz contact, the Greenwood and Williamson's model (G-W model) of rough contact and the single grain's cutting depth. Furthermore, a model of surface roughness is built based on the idea that more materials are removed at the peak on the workpiece's surface, whereas few materials are removed at the valley. The polishing experiments and simulation of cylindrical AISI 52100 steel using the polyurethane polishing pad and the free abrasives of aluminum oxide powder were performed through the Taguchi orthogonal tests, which indicated that the simulation results were well consistent with the experimental results. Under the optimal conditions, the material removal rate (MRR) of 0.40 μm/min was achieved, and the surface roughness R a was reduced from 104.90 to 20.22 nm after the polishing for 12 min. The contributions of the loading force, the abrasives concentration and the grain size on the MRR and the surface roughness are investigated in accordance with the variance and the level average response, and their reasons are discussed at different scales. It is revealed that the influences of loading force and grain size are significantly different at multi-scale. Furthermore, the parameters related to the contact (e.g., nominal contact area, average contact gap and single grain's cutting depth) under different conditions are studied. [Display omitted] [ABSTRACT FROM AUTHOR]

Lightweight, hybrid parts are extensively used in the manufacturing of modern aerospace or automobile structures like fiber metal laminates (FMLs) to replace the monolithic metallic parts. Presently, smaller and complex-shaped FML parts are made by applying the stamp-forming techniques. However, due to limited strain of the composite fibers, such techniques are unfit for forming complex profile laminated parts. This study focuses on the use of hydro-mechanical deep drawing (HMDD) for the three layers simultaneous forming of the metallic blanks to fabricate a hemispherical structure which will then be used to make a FML part. Orthogonal test strategy is formulated to investigate the influence of variables such as cavity/pre-bulging pressures, pre-bulging height, and die-binder gap to optimize the forming conditions. FE-based experimental study is done to research the thickness distribution and spring back of the formed multilayer structure. Results show that the research is sufficient in predicting these attributes and can provide a basis to understand the fundamental phenomenon for three-layered, simultaneously formed structures. Hybrid parts fabricated by using multilayer forming can expand the application areas of FMLs. [ABSTRACT FROM AUTHOR]

In this paper, TiO 2 -based geopolymer microspheres (TiO 2 @GMs) were prepared by dispersion-suspension-solidification technique using water glass activated metakaolin-based geopolymer slurry as a binder. The effects of different factors on the sphericity and particle size of TiO 2 @GMs were investigated, and the order of importance was found to be TiO 2 dosage > water volume > water glass modulus > rotation speed. Secondly, in the Fenton system under UV light irradiation, TiO 2 @GMs exhibited excellent performance in the degradation of tetracycline hydrochloride (TC). At a TC concentration of 20 mg/L, liquid-to-solid ratio of 0.3 g/L, H 2 O 2 (30 wt%) of 10 mM, and pH = 4.47, 98.6% TC was degraded by TiO 2 @GMs within 30 min TiO 2 @GMs can be easily separated from the reaction product and showed excellent recycling performance, with a degradation efficiency of 90.6% after five success reuses. Finally, a plausible photocatalytic degradation mechanism of TiO 2 @GMs for TC was discussed. This newly designed TiO 2 @GMs composite can be deemed as an alternative material for the degradation of TC and other similar antibiotic on large scale. [Display omitted] • Preparation of different TiO 2 @GMs by suspension dispersion solidification method. • The degradation process of TC by TiO 2 @GMs includes adsorption and photocatalytic. • The degradation rate of TC by TiO 2 @GMs is better than that of similar catalysts. • TiO 2 @GMs have excellent recycling and rapid settling properties. • The photocatalytic degradation mechanism of TC by TiO 2 @GMs was explained. [ABSTRACT FROM AUTHOR]

Phosphomolybdic acid is a kind of novel oxidant. The basic nitrogen compounds (BNC) in diesel was removed by phosphomolybdic acid/hydrogen peroxide as oxidant, alcohol was used as extractant to extract oxidation products from diesel. The effect of factors on removing of BNC was reviewed systematically. On the basis of single factor investigations, orthogonal experiments were done to optimize the denitrification process. The result showed that the optimum process conditions is that usage of phosphomolybdic acid is 0.020 g, volume of hydrogen peroxide is 2.5 mL, reaction temperature is 318 K, and reaction time is 35 min. The BNC in diesel is reduced from 85.79 to 21.28 μg/g, and the denitrification rate reaches 75.2% under the optimum condition. [ABSTRACT FROM AUTHOR]

The structural bent-angle drilling tool is a new type of directional drilling tool developed independently, in order to improve its build-up rate and better play its trajectory capacity, in order to successfully achieve directional drilling. To this end, this paper establishes a mechanical model of structural bent-angle drilling tools by using the longitudinal and transverse bending method of BHA continuous beams, conducts a study on the influencing factors of their skewing ability, and grasps the influence law of drilling tool structure on their skewing ability. In addition, in order to study the build-up rate of structural bent-angle drilling tools under the action of multiple factors, the drilling tool structure is optimized based on orthogonal tests. The results show that the lateral force of the bit decreases with the increase of the curvature of the well body and the decrease of the structure bending angle, the bit pressure and the diameter of the near bit holder. The build-up rate increases with the increase of the structure bending angle, the bit pressure, the diameter of the near bit holder and the distance from the bit to the near bit holder. The structure bending angle is the main factor affecting the build-up rate of the structure bending angle drilling tool, and the build-up rate of the optimized structure (structural bend angle (γ) = 0.9 ° , bit pressure (P B) = 6 t , near drill bit holder diameter (D 1) = 0.215 m , distance from drill bit to near drill bit holder (L 1) = 0.6 m) is 8.3939 ° / 30 m , which is 65.5% higher than the original structure (γ = 0.5 ° ; P B = 3 t ; D 1 = 0.212 m ; L 1 = 0.6137 m)(2.8949 ° / 30 m). The research results can lay the theoretical foundation for improving the build-up rate of structural bent angle drilling tools. • Mechanical modeling of structural bent-angle drilling tools using the longitudinal and transverse bending method. • The factors affecting the ability of structural drilling tool are studied. • The law of influence on skew-making ability of structure bent-angle drilling tool is mastered. • Optimization of the structure of structural bent-angle drilling tools based on orthogonal tests. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction (SFE) coupled with high-speed counter-current chromatography (HSCCC) was successfully used for the extraction and on-line isolation of the anthocyanidins from the petals of Chaenomeles sinensi s in two stages. The SFE parameters were optimized by an orthogonal test, and the solvent systems of SFE and HSCCC were calculated and optimized with the help of a multiexponential function model. In the first stage, the lower phase of the solvent system of n-butanol/ tert-butyl methyl ether/acetonitrile/0.1% aqueous TFA (0.715:1.0:0.134:1.592, v/v/v/v) was used as both the SFE modifier and the HSCCC stationary phase, after extraction, the extractants were pumped into HSCCC column, and then eluted with the corresponding upper phase to isolate the moderately hydrophobic compounds. In the second stage, the upper phase of the solvent system of n-butanol/ethyl acetate/acetonitrile/0.1% aqueous TFA (1.348:1.0:0.605:2.156, v/v/v/v) was used as both the SFE modifier and the HSCCC stationary phase, followed by elution with the corresponding lower phase to separate the hydrophobic compounds. With the help of two-stage SFE/HSCCC, six compounds including delphinidin-3- O-glucoside (Dp3G), cyanidin-3- O-glucoside (Cy3G), peonidin-3- O-glucoside (Pn3G), delphinidin (Dp), peonidin (Pn), and malvidin (Mv) were successfully separated within 300 min. The targeted compounds were identified by UV spectrophotometry, MS, and NMR spectroscopy. This research has opened up great prospects for the industrial application of SFE-HSCCC for the automatic extraction and separation of unstable compounds. [ABSTRACT FROM AUTHOR]