Orthogonal Test Research Articles

Preparation and properties of Ni-SiO2 superhydrophobic coating by brush plating on inner wall of pipeline

Coal is easy to stay on the inner wall of the pipeline during transportation. In order to solve this problem, it is usually necessary to improve the hydrophobicity of the inner wall of the pipeline. In this study, 45 # steel, which is wear-resistant and has good machinability, is used as the matrix for coal pipeline. Ni-SiO2 composite coatings were prepared on the inner surface of 45 # steel pipelines using a novel brush plating tool, and the hydrophobicity of the coatings were evaluated. Firstly, a series of four-factor and three-level orthogonal tests were conducted to investigate the impact of brush plating working voltage (12V, 14V, 16V), nanoparticle concentration (1g/L, 2g/L, 3g/L), brush plating duration (2min, 3.5min, 5min), and bath temperature (25 ℃, 35 ℃, 45 ℃) on the hydrophobicity of the composite coating. Subsequently, optimum process parameters were determined. Then 1H, 1H, 2H, 2H- perfluorodecyltrimethoxysilane was used to modify the coating surface in order to further improve its hydrophobicity. Scanning electron microscope (SEM), energy spectrum analyzer (EDS), optical contact angle measuring instrument, white light interferometer, Vickers hardness tester, scratch tester, friction and wear meter and electrochemical workstation were used to evaluate the coating's related properties. The experimental results show that the Ni-SiO2 nano-composite coating has a higher angle (135°) when the operational voltage of brush plating is 14V, the amount of nanoparticles is 3g/L, the brush plating time is 2min, and the bath temperature is 35 ℃. The concentration of nanoparticles is the biggest factor affecting the hydrophobicity through orthogonal test analysis, so the control variable method is used to further study the influence of the concentration of nanoparticles on the comprehensive performance of the coating. It was found that with the increase of nanoparticle concentration, surface quality and comprehensive performance of the coating showed a trend of increasing first and then decreasing, and the surface of the coating was rougher when the nanoparticles were added at 4g/L, and the maximum porosity was 31.34%. At this time, the contact angle of the super hydrophobic coating has reached 150.1°, which has reached the super hydrophobicity, and the coating has good hardness, wear resistance and corrosion resistance.

Optimization of ventilation and dust removal parameters in plateau extra-long tunnel inclined shaft based on orthogonal numerical simulation test method

Ventilation and dust removal system in the inclined shaft of the plateau long tunnel is an important component for ensuring safe excavation. The arrangement of wind tube and the volume of air flow have a significant impact on the movement of dust. In order to address the issues of poor ventilation and severe dust pollution in the inclined shaft of plateau long tunnels, this study establishes a dust generation and transportation model for the face of the inclined shaft based on the determination of dust source parameters and their physicochemical characteristics during the excavation process. The results indicate that the particles are predominantly spherical with an approximate diameter of 4 μm at a magnification of 500 times. The dust in high-altitude inclined shafts exhibits poor wettability, with a hydrophobic tendency during the excavation phase, making a ventilation dust removal scheme appropriate. After determining the physical parameters corresponding to the elevation of the inclined shaft, a series of orthogonal numerical simulations involving 3 factors at 5 levels were conducted. Analysis of range and variance revealed that optimal dust control is achieved when the air duct height is 5.725m, the distance from the working face is 21m, and the exit wind speed is 29.71m/s. Comparative analysis confirmed the rationality of the ventilation dust removal scheme under the optimal combination of ventilation parameters. This provides guidance for engineering and environmental management in similar construction scenarios.

Mechanical Characteristics and Microstructural Changes in Phosphogypsum-Cement-Lime Composite Modified Loess

Loess is widely distributed in China but suffers from inherent deficiencies limiting its direct use as a subbase material in road construction without modifications. This study investigated the utilization of Phosphogypsum (PG), an industrial waste, in a composite stabilizer containing cement, lime and slag powder for modifying loess in the subbase application. An orthogonal test design was employed to optimize the composite proportions. Laboratory tests evaluated the mechanical properties including unconfined compressive strength (UCS), splitting tensile strength, resilient modulus and water stability of modified loess over curing periods up to 90 days. Microstructural evolution was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed the composite containing 25% PG, a cement-slag ratio of 4:6 and 5% lime imparted the highest strengths. Mechanical performances increased with curing time and stabilizer content. Water stability and heavy metal immobilization were satisfactory. Microstructural results revealed microstructural densification occurred through hydration product development binding soil particles. This work demonstrated the technical and environmental viability of recycling PG through loess improvement, offering a sustainable solution for problematic soil stabilization and industrial waste utilization.

Correlation and application of thermal expansion coefficient/elastic modulus for co-sintered composite cermet/ceramic materials

Deformation and stress concentration appearing during high-temperature sintering process significantly affect production quality of solid oxide cell (SOC), due to mismatched mechanical and thermophysical properties of the sintered electrode and electrolyte. In this study, a coarse-grained molecular dynamics (CG-MD) method is developed to evaluate and correlate coefficient of thermal expansion (CTE) and elastic modulus during the entire co-sintering process (including temperature-increasing, −insulation, and -decreasing stages). It is revealed that, in the sintered porous cermet electrode, CTE primarily exhibits an increasing trend until temperature-decreasing stage. Compared to the constant values commonly applied in the literature, the elastic modulus experiences a decay trend with a reduction of 32.14 % in the porous electrode and 9.68 % reduction in the dense electrolyte. The obtained CTE and elastic modulus are correlated with the sintering parameters and further applied to a macroscopical model for predicting overall sintering warpage and stress in a co-sintered SOC half-cell composed of a thick porous electrode and a thin dense layer. The varied CTE is identified as the main factor influencing warpage deformation, while the elastic modulus as a more significant impact on the von Mises stress during the co-sintering of the half-cell. Analysis is further conducted by orthogonal testing method for sintering temperature, sintering time, material content and diameter ratio of the porous cermet nanoparticles, aiming to optimize the varied CTE and elastic modulus, particularly during the temperature-insulation process. Subsequently, the optimized properties are implemented, and it is found that, after sintering insulation for 120 min, the maximum warpage displacement is about 7.34 mm, which represents a decrease of approximately 14.11 %; while the von Mises stress is observed to be 379.24 MPa, which indicates a reduction of around 37.33 % compared with the predictions by the constant properties.

Development of high-speed precision maize metering device for dense planting pattern with standard ridges

This study proposed a high-speed precision dual-chamber maize metering device for the dense planting pattern with standard ridge promoted in China. Through theoretical analysis of the sowing process, parameters for the key components have been designed. The metering device is capable of planting two rows in a single pass for high-speed precision seeding. The effect of operating speed and negative pressure on seed metering quality was investigated. A high-speed camera was used to capture the trajectory of maize seed at different operating speeds, and it was found that intra-row shifts were caused by collisions at the mouth of the seed guide tube and rotation of the seed as it fell. Employing a two-factor, five-level orthogonal rotation test, Investigated the optimal operating parameters for the maize metering device. Response surface analysis showed that optimum seed metering quality was achieved at 14.2 km/h and 13.5 kPa. Validation tests showed a qualified rate of 97.93%, with a coefficient variation of 8.97% for this method. Additionally, an energy consumption analysis indicated a reduction in operating energy consumption of approximately 32% compared to conventional air suction seed metering devices for dense planting with large ridges on the same area of farmland. This study provides insights for reducing energy consumption in the seeding process, contributing to the sustainable development of agricultural resources.

Parameter Optimization Method for Centrifugal Feed Disc Discharging Based on Numerical Simulation and Response Surface

In this study, a centrifugal feeding disc device is proposed. To investigate the influence of the process parameters on the discharging efficiency and the lifting of the discharging efficiency, the centrifugal feeding disc device was dynamically simulated based on the discrete element method (DEM), and the simulation results were experimentally verified. Based on the quadratic regression orthogonal test method, a significant lossless regression model of process parameters and discharging efficiency was established, and the response surface of the interaction of process parameters was obtained. The results indicated that the order of influence of the process parameters on the discharging speed of the centrifugal feeding disc was as follows: outer turntable speed > inner turntable speed > inner turntable tilt angle > conical turntable angle. The interaction of the conical turntable angle and the inner turntable tilt angle had the greatest influence on the centrifugal feed disc discharge efficiency. The response surface method (RSM) was used to optimize the process parameters, and the optimal combination of process parameters included an outer turntable speed of 135 r/min, an inner turntable speed of 64 r/min, an inner turntable tilt angle of 7°, and a conical angle of 15°. The discharged efficiency of the optimized centrifugal feeding disc device was increased by 31.9%.

Research on the determination and influencing factors of topographic unsymmetrical-loaded tunnels based on the unsymmetrical coefficient

The accurate judgment of topographic bias tunnels is directly related to reasonable tunnel design and construction safety. In this study, numerical simulations were carried out to determine the unsymmetrical coefficient of topographic unsymmetrical-loaded tunnels, according to the critical thickness of the cover layer of the topographic bias tunnel proposed in the Chinese Code. The unsymmetrical coefficient was analyzed via control variable method and orthogonal test method. The results showed that it is appropriate to take 1.2 as the criterion for all types of topographic unsymmetrical-loaded tunnel in practical application. The influence of different topographic factors, mechanical properties of the surrounding rock, rock quality, construction methods and tunnel spans on the unsymmetrical coefficient were summarized by the control variable method. The results of multifactor analysis under an orthogonal design revealed that the influence of Uc is in the following order: slope angle, overburden thickness, construction method, surrounding rock quality, and height-to-span ratio.Article HighlightsThe Chinese code for topographic unsymmetrical-loaded tunnels presents a the determination of the corrected unsymmetry coefficient.Single-factor analysis determines the change pattern of the corrected unsymmetry coefficient under the influencing factors.Polar analysis based on orthogonal tests determines the strength of the factors influencing the corrected unsymmetry coefficient.

Intelligent Inversion Analysis of Surrounding Rock Parameters and Deformation Characteristics of a Water Diversion Surge Shaft

The water diversion surge shaft is vital for a hydropower station. However, the complex geological properties of the surrounding rock make it challenging to obtain its mechanical parameters. A method combining particle swarm optimization (PSO) and support vector machine (SVM) algorithms is proposed for estimating these parameters. According to the engineering geological background and support scheme, a three-dimensional model of the water diversion surge shaft is established by FLAC3D. An orthogonal test is designed to verify the accuracy of the numerical model. Then, the surrounding rock mechanical parameter database is established. The PSO-SVM intelligent inversion algorithm is used to invert the optimal values of the mechanical parameters of the surrounding rock. The support for excavating the next layer depends on the mechanical parameters of the current rock layer. An optimized design scheme is then compared and analyzed with the original support scheme by considering deformation and plastic characteristics. The research results demonstrate that the PSO-SVM intelligent inversion algorithm can effectively improve the accuracy and efficiency of the inversion of rock mechanical parameters. Under the influence of excavation, the surrounding rock in the plastic zone mainly fails in shear, with maximum deformation occurring in the middle and lower parts of the excavation area. The maximum deformation of the surrounding rock under support with long anchor cables is 0.6 cm less than that of support without long anchor cables and 4.07 cm less than that of support without an anchor. In the direction of the maximum and minimum principal stress, the maximum depth of the plastic zone under the support with long anchor cables is 1.3 m to 2.6 m less than that of the support without long anchor cables and the support without an anchor. Compared with the support without long anchor cables and support without an anchor, the support with long anchor cables can effectively control the deformation of the surrounding rock and limit the development of the plastic zone.

Effects of clogging and cleaning on sound absorption performance of rubberized porous asphalt mixture

ABSTRACT The rubberized porous asphalt mixture (RPAM) has both the sound absorption capacity of air voids and the damping performance of rubber particles, which is a high-potential noise reduction pavement. However, the air voids are inevitably subjected to clogging, resulting in insufficient sound absorption performance. Moreover, it is not clear whether a large amount of rubber particles exacerbates the attenuation of sound absorption performance. Therefore, the purpose of the paper was to explore the attenuation law of sound absorption performance of RPAM under the action of multiple clogging cycles, and then optimise the preparation parameters to improve noise reduction durability. Constant head permeability test was carried out to simulate the clogging process, and manual and high-pressure washing were used to clean the clogged samples. The results showed that the attenuation process of sound absorption coefficient conformed to exponential function. The interconnected air voids were mainly clogged in the fast attenuation phase, and the open voids were clogged in the slow attenuation phase. It was more efficient to clean samples completely clogged than to clean samples clogged for three cycles. More importantly, rubber particles accelerated the attenuation of sound absorption performance during the clogging process. However, the noise reduction durability of RPAM optimised by orthogonal test was significantly improved, even better than that of porous asphalt mixture without rubber particles.

Experimental Investigation of Tensile, Shear, and Compression Behavior of Additional Plate Damping Structures with Entangled Metallic Wire Material

To fulfill the vibration damping requirements of plate structures under complex conditions, additional damping structures with entangled metallic wire material (EMWM) are proposed based on the excellent physical properties of EMWM. A batch of specimens with different filament diameters, densities, and thicknesses are prepared. The stiffness and loss factors are taken as the evaluation indexes, and orthogonal tests are conducted to obtain the tensile, shear, and compression properties. The results show that the optimal parameter combinations can be obtained through orthogonal tests. For the specimens with optimal parameter combinations, the mechanical tests under different loading rates and loading displacements are carried out. With the increase in loading rate, the tensile and shear forces appear to display fracture failure in advance, and the compression performance is stable without significant changes. The change rule under each mechanical test is explored using the stiffness and loss factor evaluation index. It provides a reference for the analysis of the preparation parameters of subsequent additional damping structures with EMWM.

Preparation and characterization of UV-Curable phosphate ester-containing acrylate resin adhesive for dental zirconia restorations

Fumed silica was utilized as a filler, methacryloyloxydecyl dihydrogen phosphate (MDP) served as a reactive monomer, and acrylate acted as a resin monomer to develop zirconia adhesives for dental acrylate resins containing phosphate esters. A uniform design, orthogonal tests, and single-variable experiments were conducted to vary the composition of each component. The effects of different composition ratios on the mechanical properties, hydrophilicity, flowability, and volumetric shrinkage of dental resin adhesives were studied in detail. The resin matrix composition included 43.6 wt% Bis-GMA, 28.2 wt% triethylene glycol dimethacrylate (TEGDMA), and 28.2 wt% hydroxyethyl methacrylate (HEMA). The photocurable system composition consisted of 4 % camphorquinone (CQ), 2.4 % ethyl 4-dimethylaminobenzoate (EDB), 3.2 % dimethylaminoethyl methacrylate (DMAEMA), and 1 % butylated hydroxytoluene (BHT). The adhesive monomer was 12 % MDP, and the filler system comprised 2 % R972 and 3 % OX50. The light curing time was set at 60 s. The adhesive exhibited optimal performance with a bonding strength of 35.9 MPa and a volumetric shrinkage of 13.3 %. According to this study, the proposed zirconia adhesive featuring a phosphate-containing acrylic ester group is a potential light-curing dental resin adhesive with a straightforward synthesis procedure, minimal volumetric shrinkage, good bonding strength, and an appropriate photocuring time.

Working Condition Sensitivity Analysis and Optimal Structure Parameter Determination of IVT Based on CFD and Orthogonal Experiment

To address liquid accumulation in horizontal gas wells, a specialized internal vortex tool (IVT) was developed for use in the horizontal sections, functioning as a drainage gas recovery device. This tool operates by leveraging centrifugal forces generated during fluid swirl to separate liquid from gas. The study examined the performance of IVT under various operational conditions and sought to identify optimal structural parameters. Through a controlled variable approach, the impact of inlet velocity and the water-gas volume ratio on pressure drop range, MGV (maximum gas velocity), and MVFLP (maximum liquid phase volume fraction) was analyzed. The results indicated that when the inlet velocity is between 2-4m/s and the water to gas volume ratio is between 0.5-2m3/104m3, the smaller the inlet velocity and the smaller the water to gas volume ratio, the better the gas-liquid separation effect of the IVT. An orthogonal test was subsequently employed to fine-tune the tool's structural parameters for different conditions, culminating in the creation of a comprehensive optimization chart for IVT. This study can effectively design drainage gas production tools for gas wells under different working conditions, reduce energy loss during drainage gas production, effectively utilize downhole resources, and achieve the goal of increasing natural gas well production and reducing costs.

Preparation and properties of phosphogypsum-based calcined coal gangue composite cementitious materials

Phosphogypsum (PG) and coal gangue (CG), as the largest solid waste today, the effective utilization of this part of the resource can help to alleviate environmental pollution and resource waste. The aim of this study was to utilize the excellent thermal insulation properties of original PG and the regulation of hydration products by calcined coal gangue (CCG) to produce phosphogypsum-based calcined coal gangue composite cementitious materials (PBCM). The optimal ratio of PBCM was studied through a combination of mechanical properties and thermal insulation properties. Finally, the effect of the foam factor is further investigated. The results show that: CCG can be used as a silicon-rich material with gelling properties to regulate the hydration products generated. The test block with a foam content of 8% has the best performance, with a compressive strength of 2.53MPa and a thermal conductivity of 0.1427W/(m·K). The optimal experimental scheme obtained from the orthogonal test was as follows: The optimal experimental design obtained from orthogonal experiments was as follows: PG, quicklime (QL), sulfoaluminate cement (SAC) and foam contents were 45%, 8%, 8% and 8%, respectively. The CCG: cement and water-solid ratios (W/S) were 3:7 and 0.275, respectively. The development of high-performance composites presented in this study is conducive to enhancing waste utilization and provides a novel approach as well as a theoretical foundation for insulating building materials in practical engineering applications.

Development and optimization of ultimate performance self-levelling epoxy asphalt concrete (USEA) for prefabricated deck pavement

Developing prefabricated bridge deck pavement systems can fundamentally avoid the drawbacks caused by traditional on-site construction such as poor continuity of the construction process and significant differences in pavement layer performance. Prefabricated bridge deck pavement requires that the bridge pavement is completed with the steel deck together in the factory indoors thus it needs the concrete has better self-leveling characteristics which is rare for existing pavement materials. This article develops the ultimate performance self-levelling epoxy asphalt concrete (USEA) which both have excellent self-leveling properties and comprehensive performance. The study initially established the self-leveling asphalt concrete rolling model based on asphalt film thickness theory and Hertz contact theory and the critical rolling mechanical calculation results states that the aggregate particles and the skeleton amounts are the key elements for fluidity of concrete. Comprehensive the analysis of rolling model and research on the curing reaction process of epoxy resin, the study raises the material configuration of USEA and determine the gradation by the Bailey’s method. To guarantee the better pavement performance of USEA, the study designs the orthogonal test and establish the Entropy-TOPSIS model to optimize the details mortar schemes of concrete. Through the model calculation, the epoxy resin content and the SBS modified asphalt oil-stone ratio are determined as 20 % and 8.0 % respectively. In this scheme, the high temperature stability is 2805 times·mm-1, the low temperature bending strain is 3662με and the fatigue life can reach 1.200 million times. The study provides a material selection for the development of prefabricated bridge pavement system and the technical reference for the development of other self-leveling materials which has constructive practical significance.

Study on oil film spreading characteristics on the jet lubricating tooth surface of aviation herringbone gear

Purpose During the oil lubrication process of aviation herringbone gears, lubricating oil is injected into and spreads around the tooth surface. Its spreading characteristics directly affect the lubrication state and transmission efficiency of gears. This study aims to investigate the effect of changing the injection parameters and gear operating conditions on the oil film deposition during injection lubrication. Design/methodology/approach The computational fluid dynamics method was used to establish the computational domain for the simulation and optimization using an orthogonal test. The oil film spreading and thickness of the tooth surface were calculated with the change in gear speed, fuel injection distance and fuel injection speed. Optimized oil injection lubrication parameters were obtained, and design ideas were provided for the oil injection lubrication analysis of aviation herringbone gears. Findings Under different operating conditions, such as varying the injection speed, gear rotational speed and injection distance, there were differences in the distribution of the lubricating oil film formed on the tooth surface. The thickness of the oil film decreases as the distance from the injection port increases. The thickness of the oil film deposition can be increased by increasing the injection velocity and reducing the gear rotation speed. The injection distance had a relatively small effect on the spreading thickness of the deposited oil film, affecting only the dynamic spreading process of oil film deposition. Furthermore, the simulation results are compared with the analytical calculation results, and finally the experimental verification is carried out. Originality/value Oil spray lubrication characteristics are important for achieving precise gear lubrication designs in the aerospace field. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2023-0250/

Optimization of polishing fluid composition for single crystal silicon carbide by ultrasonic assisted chemical-mechanical polishing

Silicon carbide (SiC) is renowned for its exceptional hardness, thermal conductivity, chemical stability, and wear resistance. However, the existing process is difficult to meet the high standards of uniform corrosion in its polishing process and surface roughness and flatness after polishing, new polishing fluids and technique optimization are crucial for development. The study optimized and validated the composition of the polishing fluid used in ultrasonic-assisted chemical-mechanical polishing (UACMP). Abrasives significantly influenced the material removal rate (MRR) and surface roughness (Ra), contributing 67.63% and 56.43%, respectively. Organic bases and pH buffers significantly affected Ra, accounting for 19.66% and 21.44%, respectively. The optimum composition was determined, consisting of triethylamine (3wt%), potassium hydrogen phthalate (1wt%), a composite of silica and alumina abrasive particles (5wt%), and hydrogen peroxide (6wt%), which reduced the Ra from 95 nm to 3 nm. The MRR achieved 25.96 nm/min. In comparison to the 7 nm minimum roughness from the orthogonal test, the optimal scheme’s Ra was reduced by 57.14%, leading to a significant enhancement in overall surface quality. In this paper, a new type of additive is added to prepare the polishing liquid, which provides a new idea for the UACMP of SiC and has a great impact.

Optimization Study of the Structural Parameters of an Artificial Percolation Intake Riverbed Based on a Numerical Orthogonal Test

Research on water abstraction techniques in sandy rivers is crucial for addressing water scarcity issues in northern China. This study introduces an artificial percolation water intake riverbed structural model designed to prevent sand intake and facilitate the extraction of clear water from sandy rivers, the main function of which is to artificially construct a helical flow field to realize the separation of water and sand and, at the same time, percolate the water. In this paper, we use a numerical orthogonal test method to study the influence of structural parameters and their combinations on water extraction by percolation, and the preferred combination of structural parameters. The main conclusions of this paper are as follows: Under the condition of certain structural parameters of the artificial riverbed, the single-width flow rate has an important effect on the mean circumferential flow rate of the vortex tube and the vortex tube seepage volume. The effect of different structural parameters on the mean circumferential flow rate of the vortex tube and the vortex tube seepage varies in magnitude. The longitudinal slope of artificial riverbed i had the greatest and most significant effect on the mean circumferential flow rate of the vortex tube, and each structural parameter had some effect on the vortex tube seepage Q but not to a significant level. When the sand content of the water flow is 15 kg/m3 and the maximum sand grain size of the suspended mass is 2 mm, the optimal structural parameter combinations of the artificial riverbed under different working conditions are as follows: Combination 20 is the optimal structural parameter combination for q = 0.3 m2/s; Combination 24 is the optimal structural parameter combination for q = 0.6 m2/s; and Combination 24 is the optimal structural parameter combination for q = 0.9 m2/s. The present study is of great significance for understanding the influence of each structural parameter and its combination on the effect of the water intake and sand discharge of an artificial percolation intake riverbed, and for optimizing the combination of the structural parameters of an artificial percolation intake riverbed.

Optimum Design of Profiled Root–Trimming Device for Pull–Cut Harvester of Leading–Drawing–Cutting Type

In this study, a leading–drawing–cutting–type profiled root–trimming device was designed to address the problems of high impurity and damage rates that occur with the operation of a pull–cut garlic harvester. The main components of the designed device include a pull–clamp mechanism, roll–pulling mechanism, root–trimming knife mechanism, lifter, gearbox, universal drive shaft, motor, and frame that, together, can complete the root–trimming operation for a pull–cut garlic harvester. An orthogonal regression test was carried out by taking the roller diameter, the roller inclination angle, the knife rotation speed, and the working speed as factors and by taking the impurity rate and the damage rate as indices. The results of the orthogonal regression test showed that the impurity rate was most strongly affected by the roller diameter, followed by the knife rotation speed, the working speed, and the roller inclination angle. Meanwhile, the damage rate was most strongly affected by the knife rotation speed, followed by the roller diameter, the working speed, and the roller inclination angle. The regression analysis showed that when the roller diameter was 100 mm, the roller inclination angle was 25°, the knife rotation speed was 200 r·min−1, and the working speed was 1.22 km·h−1, the comprehensive trimming quality reached its maximum value of 97.82%. The verification result of the parallel test gave a value of 97.52%, which was mainly affected by the irregular sizes of the bulbs, but it showed no significant difference from the regression analysis results. The tests verified that the profiled root–trimming device could be applied to develop the technology of garlic pull–cut harvesters.

Preparation and tissue structure analysis of horse bone collagen peptide

Horse bone is rich in collagen, with a composition similar to that of human collagen. Collagen peptides supply nutrients needed for human growth that act as antioxidants, lower blood pressure. This study explored the extraction of collagen and the preparation of collagen short peptides from Mongolian horse bones. Bones were collected from horses of varying ages, and the collagen content along with calcium salt distribution were observed through staining and imaging analyses. Next, the bones were processed into a powder and then subjected to ultra-high-pressure processing for degreasing. The degreasing conditions were optimised by single-factor and orthogonal tests. Following this, collagen was extracted using an acid-enzymatic method, and its structural characteristics and thermal stability were assessed. The collagen short peptides were extracted from the collagen samples, and the effects of the enzymatic hydrolysis time, temperature, pH, and enzyme amount on the extraction rate were evaluated. Finally, the resulting collagen peptides were analysed for antioxidant activity. In summary, this experiment optimised the extraction conditions for horse bone collagen, demonstrating that the ultra-high-pressure method minimally affects collagen structure, and the extraction rate was high. Hence our method has significant development potential.

Ultra-high pressure assisted extraction of water-soluble polysaccharides from Moringa oleifera seed husks and their antioxidant activities

ABSTRACT The process conditions and antioxidant activity of ultra-high pressure assisted extraction of polysaccharides from Moringa oleifera seed husks were studied. Taking the yield of polysaccharides as the index, the effects of degree of crushing, extraction pressure, holding pressure time and material-to-liquid ratio on the yield of polysaccharides from Moringa oleifera seed husks were investigated. The optimal extraction conditions were determined by single-factor test and orthogonal test: a holding time of 10 min, a material-to-liquid ratio of 1:25, an extraction pressure of 350 MPa, and a polysaccharide yield of 0.264%. Its antioxidant activity can be determined by measuring the total antioxidant capacity and their ability to scavenge DPPH and ·OH radicals. The results showed that the IC50 of Moringa oleifera seed husk polysaccharides on DPPH and hydroxyl radicals were 0.0662 g/L and 0.0844 g/L, respectively. The total antioxidant capacity was 0.1826 mm/g (expressed as the equivalent concentration of ferrous sulfate). Compared with hot water extraction methods, ultra-high pressure assisted extraction methods can shorten extraction time, improve extraction efficiency. The water-soluble polysaccharides extracted from Moringa oleifera seed husks by ultra-high pressure assisted extraction technology also have higher antioxidant activity than that by hot water extraction method at the same concentration.