bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation analysis of bubble coalescence behavior characteristics in non-Newtonian fluids based on the phase field method
Authors: Long Li
Published: March 2024

Gas-liquid two-phase flow is widely used in various fields of chemical production because of its stability. The bubble coalescence behavior has a significant impact on the size, shape and movement of bubbles. These parameters are important parameters for affecting the interphase mass and heat transfer processes and equipment performance. This paper presents a simulation study of the bubble coalescence behavior of non-Newtonian fluids using the phase field method through simulation software. The relative location of bubbles were divided into three types: vertical, parallel and random; and also the distribution of bubbles can be divided into three cases: symmetric, left-skewed and right-skewed. This paper focuses on the influence of the arrangements of the bubbles on their coalescence behavior in non-Newtonian fluids. The results show that in non-Newtonian fluids, the relative distance of the bubbles and the flow characteristics of the fluid are both key factors in whether bubble coalescence can occur, and they exhibit different patterns of action when the bubbles are in different arrangements. Also bubbles show different patterns of motion in different distributions.
Comparative study of different cavitation erosion assessment methods in cavitating flow around a Delft Twist hydrofoil
Authors: Huang Jiale , Deng Linfeng , Ji Bin , Cheng Huaiyu
Published: March 2024

Cavitation erosion is a common phenomenon in hydraulic machines, which severely threatens their stable operation. Although several methods for erosion risk assessment have been proposed, few researchers work on the comparative study of different cavitation erosion assessment methods. Therefore, this study utilized Large Eddy Simulation (LES) combined with Zwart-Gerber-Belamri (ZGB) cavitation model to conduct the numerical simulation for the cavitating flow around a Delft Twist hydrofoil. The Erosive Power Method (EPM), Improved Gray Level Method (IGLM) and Energy Conservative Method (ECM) are employed separately to evaluate the cavitation erosion. Among the three results, the EPM results cannot accurately predict erosion in the middle region and trailing edge region, where the U-shaped vortex collapse. The results of IGLM and ECM can predict the erosion in the middle region and erosion caused by the U-shaped vortex at the trailing edge. IGLM still needs artificial thresholds, while ECM emphasizes areas with higher cavitation risk by amplifying parameter n. The ECM method is more objective from the simulation results.
Numerical implementation and verification of the Zwart-Gerber-Belamri cavitation model with the consideration of thermodynamic effect
Authors: Ezekoye David , Zheng Zhi-Ying , Wu Jian
Published: March 2024

In the world of pumps, turbopumps, and industrial applications, the absorption and release of latent heat in high-temperature zones play a pivotal role in the cavitation process. This phenomenon exerts a profound influence on system performance, especially when handling hot and cryogenic fluids, which are particularly susceptible to thermodynamic influences. The pressing need arises for a robust computational approach to address the intricacies of thermodynamic effects on cryogenic cavitation. The study at hand introduces a modification to the Zwart-Gerber-Belamri cavitation model, incorporating thermodynamic considerations to simulate quasi-steady cavitating flow around a NACA0015 hydrofoil. The SST k-ε turbulence model and homogeneous mass transfer cavitation model are employed to account for thermal effects, while the Clausius-Clapeyron equation is utilized to adjust the saturated vapor pressure within the cavitation model. Comparing the results with experimental data from Cervone et al. [1], especially in the thermal domain, reveals congruence in the estimated pressure and temperature drop (ΔT) within the cavity under varying free stream temperature conditions. Notably, thermodynamic effects exert a significant influence on cavitation dynamics during the phase-change process, potentially hindering or delaying cavitation in hot and cryogenic fluids. This enhanced cavitation model offers a marginally improved prediction of cavitation in water.
Contribution of interphase force curl to rigid vorticity transport in water-sand two-phase flow with fine particles
Authors: Chen W H , Wang F J , Wang C Y , He C X , Chen X , Tang X L
Published: March 2024

Rigid vorticity transport equation is an effective tool for describing the intuitive vortex evolution characteristics. Compared to single-phase flows, the curl of the interphase force appears as a new source term of this equation under the condition of multiphase flows, which may cause additional contributions. However, the effects of the interaction force on rigid vorticity transport in water-sand two-phase flows with fine particles are still unclear. In this article, taking the Karman vortices induced by a hydrofoil as a typical case, the distributions of rigid vorticity in single-phase flows and two-phase flows were compared, and the dynamics mechanism of the dominant interaction force was analyzed. The following notable results are obtained. Firstly, the drag force can be regarded as the dominant interaction force. Secondly, the effect of the drag force on a vortex tube is mainly manifested as inducing normal strain and the contribution is relatively low. Thirdly, there are only slight differences in the waveform, amplitude, frequency of rigid vorticity and apparent vortical structures between the single-phase flows and the fine-particle two-phase flows. These new findings are helpful for understanding the vortex evolution in water-sand two-phase flows with fine particles.
Numerical investigation of partial cavitation in a Venturi tube by Eulerian-Lagrangian multiscale modelling
Authors: Zhou Zhizhong , Li Linmin , Xuan Xiaoxu , Chen Songying , Yoon Joon Yong , Sun Xun
Published: March 2024

The cavitating flow in a Venturi tube has a complex flow structure. In this paper, the partial cavitation in an axisymmetric Venturi tube, dominated by bubbly shock, is investigated by utilizing Eulerian-Lagrangian multiscale modelling. The unsteady partial cavitation is simulated by Large Eddy Simulation coupled with the Volume of Fluid and the Discrete Bubble Model. The numerical results show a well agreement with the high-speed photography. Through a comprehensive analysis of the development and transportation of macro cavities and micro bubbles, a detailed explanation of the cavity shedding process triggered by bubbly shock is provided. The results highlight the precise capability of the multi-scale method in elucidating the intricate flow field induced by partial cavitation. The findings may pave the way for the further investigations on the underlying mechanisms of partial cavitation, fostering a deeper understanding of bubbly shock dominated cavitating flow.
Research on cavitation characteristics of water-jet pumps with different blade tip clearances based on entropy production theory
Authors: Fei Z Y , Guo Q , Huang X B , Ming X
Published: March 2024

Water-jet pumps are widely used in ship and other power fields. An axial-flow water-jet pump is studied with different size of tip clearance, and the cavitation characteristics are studied based on the theory of entropy production. Modified SST with curvature correction and modified Zwart cavitation model based on vortex identification are adopted, and the numerical calculation method is verified by reference experiments of a model pump. Under normal operating conditions, the results show that when the size of the tip clearance varies from 1.6‰ to 7.9‰ of the impeller diameter, efficiency takes a linear decrease accordingly, and the total entropy production increases linearly. At the same time, the main energy dissipation mode changes from wall dissipation to turbulent dissipation. Under severe cavitation conditions the total entropy production adds 30%. The water-jet pump shows that the entropy production in the impeller section is the highest, which accounts for 40%-50% and is closely related to the vortex and cavitation flow field in the tip clearance of the impeller. The tip leakage vortex region causes cavitation, but significant energy dissipation occurs at the outer edge of leakage vortex and on the nearby wall area, while the attached cavitation on the blade surface is the main source of turbulent dissipation.
Frictional pressure drop of two-phase flow in a horizontal tube under low void fraction
Authors: Feng C N , Miyagawa K , Kawahara T , Katayama Y
Published: March 2024

The frictional pressure drop of air-water two-phase flow is a crucial parameter in hydrodynamic calculations. Solving for precisely calculating frictional pressure drop in it remains a significant challenge due to the various factors affecting two-phase flow characteristic. Currently, various scholars have proposed multiple frictional pressure drop prediction models of two-phase flow. Typically, these models exhibit great errors under low void fraction. To more accurately predict the frictional pressure drop of two-phase flow under low void fraction, this paper experimentally investigated the flow characteristics of air-water two-phase flow in a horizontal tube. The flow rates for water and air are 3-6 kg/s and 0.0004-0.003 kg/s, respectively. The void fraction ranged from 0 to 0.07%. The experimental data and flow patterns of two-phase flow were analyzed, and these data was compared with commonly used frictional pressure drop prediction model of two-phase flow. The results indicated that: (1) Within the scope of this paper, two-phase flow pattern observed include bubbly flow and slug flow. With changes in the void fraction, the number of bubbles and the length of slugs have undergo alterations; (2) All three commonly used prediction models underestimated the frictional pressure drop under low void fraction. Therefore, Considering more influencing factors to improve the accuracy of prediction model is the next research direction. This research has showed the limitations of existing prediction models and emphasized the importance of research on frictional pressure drop of two-phase flow.
Numerical analysis of flow instability with vortex cavitation in venturi tube
Authors: Nakashima T , Enomoto Y , Nakamura T
Published: March 2024

The swirling flow with cavitation can cause pressure pulsations in a draft tube of a hydro turbine at off-design operating conditions. Especially at the full load condition, the cavitation volume may fluctuate greatly, causing pressure pulsations with flow rate fluctuations known as cavitation surge throughout the hydraulic system. The cases that predicted the phenomenon qualitatively using the CFD analysis have been reported previously, whereas the methods to predict the cavitation volume and the fluctuation frequency in the cavitation surge condition quantitatively have not yet been established. Therefore, in this study, unsteady CFD analysis was conducted for the experimental apparatus that simulates the flow in the draft tube downstream of a runner using the stationary guide vane and the venturi tube. In CFD analysis, the influence of the turbulence models by using LES and SST and the influence of the number of meshes in LES simulation were investigated. It was founded that LES simulation captured the vortex generation finely and improved the prediction accuracy of the cavitation volume than SST simulation. On the other hand, it was founded that too fine mesh has a small effect on the prediction accuracy of the cavitation volume, although the resolution of the vortex is improved.
Structure optimization of DTH hammer piston based on RBF neural network and WSO algorithm
Authors: Wang Jiangang , Feng Ding , Liang Jinli , Zhao Yu
Published: March 2024

To address the issue of piston fracture due to insufficient strength in the Down-The-Hole (DTH) hammer. The effect of the pressure state of the gas chamber on the piston motion is considered. A piston motion model is established based on the steady flow energy equation and the working principle of the piston. The finite element method is used to analyze the dynamic response of the piston during the impact of the drill bit. RBF neural network is employed to construct a surrogate model for the relationship between piston structural parameters (front-end diameter, front-end length, and center bore) and piston strength and performance (impact energy, frequency, and gas consumption). By combining this model with the white shark optimization search algorithm, the design of the DTH hammer’s piston structure parameters is optimized. The minimum piston mass is the objective function. Impact energy, frequency, air consumption and stress are constraint factors. The effect of piston life is considered while meeting rock drilling efficiency. The optimization results show that the stresses in the optimized piston structure are reduced by 13%. The proposed RBF performance prediction model combined with the optimal search algorithm can significantly improve the optimization efficiency.
The design and testing of a high reaction turbine blade profile
Authors: Yang Changzhu , Fan Liyun , Yan Wei , Zhang Hanwen
Published: March 2024

In order to improve the efficiency of high pressure cylinder of 50∼350MW steam turbine and reduce the manufacturing cost, a steam turbine blade profiles are designed. The numerical simulation and test study of the new blade profile are carried out, and the performance of the new blade profile with variable inlet angle and mach number is discussed, and the performance of the new blade profile is improved when applied to stage environment. The results show that the performance of variable inlet angle and variable mach number of the new blade profile is better than that of the original profile. The aerodynamic efficiency of the new blade profile is obviously better than that of the original profile. The blade loss of the new design profile is lower than the original profile, and the aerodynamic efficiency of the new design profile is obviously better than the original profile. The stage test results show that the efficiency of the new design profile increases by about 0.5% compared with that of the original profile.
Turbine performance improvement by the multi-objective optimization for variable nozzle vanes of turbocharger
Authors: Wang Wantong , Morita Junnosuke , Sakurai Yusei , Ueno Takahiro , Morita Isao , Novo Patxi Garcia , Sakaguchi Daisaku
Published: March 2024

This paper focuses on improving the turbine efficiency of a variable geometry system (VGS) of turbochargers for internal combustion engines. The study investigates the shape optimization of the turbine nozzle vane and impeller of VGS through a meta-model-assisted multi-objective optimization. The design parameters of the optimal solution were compared with the baseline model for data and internal flow field analysis to explore which parameters have an impact on performance improvement. It was found that the optimized trailing edge angle of the nozzle vanes allows the exhaust airflow to reach the impeller with the minimum traveling path, and it contributes to mitigating the mixing loss of the flow to the impeller blade. The optimized impeller blade angle leads to an increase in torque and a higher turbine efficiency (> 5%) with the narrow opening, also ensuring a high mass flow in the wide opening. This outcome can contribute to the design and development of high-performance and low-emission turbocharger systems by optimizing the performance of turbine design parameters simultaneously.
Experimental study on a loop thermosyphon with microencapsulated phase change material suspension
Authors: Tan Zhenyu , Li Xunfeng , Zhou Jingzhi , Huai Xiulan
Published: March 2024

Microencapsulated phase change material suspension (MPCMS) represents an innovative category of functional thermal fluids. This novel working fluid not only preserves the substantial energy density and high latent heat of phase change materials (PCM), but also mitigates the issues related to PCM, including susceptibility to aggregation and low thermal conductivity. This article selects phase change microcapsules with a phase change temperature of 70 °C, and uses pure water as the base liquid to prepare MPCMS as the working fluid for the loop thermosyphon. A series of heat transfer experiments are conducted, and the results are compared with those of pure water experiments. A 135mm*650mm copper loop thermosyphon, is designed and constructed to investigate the effect of various input power on the heat transfer performance. The results show that the addition of MPCMS can reduce the wall temperature by up to 2.9°C and the loop thermal resistance by 6.3%. Compared with water, the loop thermosyphon with MPCMS has better start-up characteristics. The performance of the MPCMS is affected by various parameters, which are interconnected. Particles in close proximity to the wall display erratic movement, fluctuating across different temperature zones, thereby undergoing a continuous cycle of melting and solidification. This study establishes a basis for further investigation into the practical implementation of MPCMS in industries.
Microstructure and properties of 316L cladding layer on Hydraulic support cylinder
Authors: Xu Lin , Zhang Haiyu , Liu Eryong , Zhang Jingli , Jiao Yang , Wang Ming , Zhan Lihua , Tang Yan
Published: March 2024

Scanning speed refers to the motion of the laser beam on the surface of the substrate. The transformation of heat affected zone and microstructure of the matrix were observed by increasing the motion speed and martensite content. The effect of scanning speed on the microstructure and properties of the coating was studied. In addition, the electrochemical properties and hardness of the workpiece are also improved.
Study on the impact of Cr content on the microstructure and properties of Cu-Cr alloys
Authors: Liu Keming , Yang Xilian , Wen Jiahao , Shi Jinke , Xu Jiekai , Zhang Yuhan , Fu Kai , He Xuelong , Shen Zhi
Published: March 2024

Copper has excellent electrical conductivity, but the disadvantages of low strength and hardness limit its application range. In this paper, Cu-XCr (X=5, 7, and 9, where 5, 7, and 9 are all mass percentages) alloys were treated as the object of study; the impacts of Cr contents on the microstructure, Vickers hardness, and conductivity of Cu-XCr alloys were investigated using an XHC-SV2 upright metallographic microscope, a digital display Vickers hardness tester, and a Sigma2008C digital metal conductivity meter; the optimal Cr content was determined by the comprehensive performance parameter Z. The research results showed that the second phase of Cu-XCr alloys contained dendritic, nearly spherical, and other shapes. The size was relatively small, and the distribution was relatively uniform; the Vickers hardness improved and the electrical conductivity declined with climbing Cr content; when X=7, the comprehensive performance parameter Z of Cu-XCr alloys reached a maximum of 6.7×105 HV2·%IACS.
Synthesis of PMM and Synergistic Flame Retardant Effect with Ammonium polyphosphate
Authors: Dong Yanmao , Shen Zhiyang
Published: March 2024

A novel flame retardant poly {[(2-Methyl-acrylic acid 2-(dimethoxyphosphoryloxy)-ethyl ester]-co-[2-Methyl-acrylic acid 2-(trimethoxysiloxy)-ethyl ester]} (PMM) containing dimethoxyphosphoryloxy and trimethoxysiloxy groups in side chains was synthesized. The structure of PMM was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), and the thermal performance of PMM was characterized by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of PMM on polypropylene’s flame retardancy and thermal behaviors was investigated by limited oxygen index (LOI), vertical burning test (UL-94), and TG tests. The experimental results indicate that the addition of PMM helps to improve the flame retardancy and thermal stability of PP. When the addition of PMM and APP in PC was 15% and 20%, the LOI value of PC reached 28.4%, and the UL-94 test rating reached V-0 level. The charred structure observed by scanning electron microscopy (SEM) indicated that the char surface for PP/APP/PMM system holds an intumescent char structure compared to neat PP, and the synergy exists in the composites. The PMM slightly decreased the tensile property in terms of strength but increased the elongation at break for PP composites.
High temperature chlorine corrosion resistance of gradient high entropy alloy coatings prepared by high-velocity-oxygen-fuel spraying
Authors: Chu Xi , Hu Shu-sen , Dai Zhen
Published: March 2024

The effect of different gradient structures on the high temperature chlorine corrosion resistance of gradient high entropy alloy coating was studied to improve the service life of the heating surface of a waste-incinerated boiler. NiCrAl ceramic composite coating (NC), high entropy ceramic composite coating (HC), and gradient high entropy alloy coating (TC) were prepared on 12Cr1MoV substrate by high-velocity-oxygen-fuel spraying. The effects of morphology and microstructure of different coatings on thermal shock resistance and high temperature chlorine corrosion resistance were studied. The results indicate that the porosity of NC coating, HC coating, and TC coating decreased in turn. In the thermal shock resistance test from 800°C to room temperature, the average number of thermal shock of TC coating can reach 21. The mass change of TC coating in 650°C high temperature Cl corrosion resistance test is less than 30 mg/cm2 after 50 hours. In summary, the gradient high entropy alloy coating with HEA as the metal bonding phase can improve the density of thermal spraying gradient coating, and enhance the thermal shock resistance and high temperature Cl corrosion resistance of the coating. Based on the comprehensive on-site application results, it can be concluded that the use of high velocity oxygen flame gradient high entropy alloy coating can effectively improve the density, thermal shock resistance, and high temperature Cl corrosion resistance of the thermal spraying gradient coating on the heating surface of the boiler, and has broad application prospects.
Doping of metal into transition metal dichalcogenides PdTe2
Authors: Chen Li , Wang Yanan
Published: March 2024

Rh-doped PdTe2 single crystals were successfully prepared using the solid-state reaction. The change of lattice constants and T
c with increasing Rh content were studied and investigated. It was found that there is a very slight increase of lattice constant c with increasing Rh content. The values of T
c were above 2 K when Rh content is equal to 0.05 and 0.1. The largest T
c was~2.7 K for Rh0.05PdTe2 single crystal. T
c does not increase with increasing x from 0.05 to 0.1. M-T measurement of Rh0.05PdTe2 single crystal with applied magnetic field H perpendicular to the c axis and along and c axis gives evidence of type II superconducting behavior. This study shows Rh doping is a promising method to increase T
c and investigate SC in PdTe2.
Design and Synthesis of Polyacrylamide Quaternary Ammonium Salt with Antibacterial Activity
Authors: Shan Chaoyue , Huang Yongle , Wang Yu
Published: March 2024

Propenamine quaternary ammonium salt (NNDBAB) containing unsaturated bonds was synthesized from propenamine and bromobutane by alkylation reaction. Using NNDBAB as a monomer, PNNDBAB was further self-polymerized by free radical polymerization to produce propenamine quaternary ammonium salt (PNNDBAB). The structure of NNDBAB was characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The antibacterial properties of PNNDBAB were characterized by an antibacterial zone test, minimum inhibitory concentration, and smear plate counting. The results showed that PNNDBAB had good bacteriostatic activity, the diameter of the bacteriostatic zone was 27 mm, the minimum bacteriostatic concentration was 0.5 mg/L, and the bacteriostatic rate of 1wt% was 71.0%. The bacteriostatic effect was significant. The antibacterial effect of PNNDBAB is long-lasting. When added to the emulsion, the antibacterial effect of PNNDBAB can be sustained within 15 days.
Study on the freezing resistance and repair technology of prestressed high-strength concrete pipe piles
Authors: Qi Guangzheng
Published: March 2024

This article takes a prestressed high-strength concrete tube pile (PHC tube pile) in Tianjin Port as the research object, considers the influence of the type of admixture, forming process, and maintenance method in the process of concrete fabrication, and carries out a rapid freeze-thaw test of PHC tube pile concrete. The changes in the mass loss rate, relative compressive strength, and relative dynamic modulus of elasticity with the number of freeze-thaw cycles, as well as the influence characteristics and mechanism of the admixture type, forming process, and curing method, were obtained. Based on this study, the repair and reinforcement of the base concrete were carried out using ultrahigh toughness cementitious composites and cementitious permeable crystalline composites, and a rapid freeze-thaw test was conducted on the repaired concrete specimens to verify the repair and reinforcement effects of the two materials. The study showed that the mass loss rate, relative strength, and relative dynamic elastic modulus can better characterize the freezing resistance of PHC piles, and it is safer to use the relative dynamic elastic modulus as the evaluation index of the freezing resistance of PHC pile concrete than the mass loss rate. The concrete admixture, forming process, and maintenance method have significant effects on the freezing resistance of the PHC pipe pile mix. The splitting damage surface of both ultrahigh-toughness cementitious composites (UHTTC) and cementitious capillary crystalline waterproofing (CCCW) repaired concrete is a reinforced surface, and both repair materials can improve the freezing resistance of PHC pipe piles through the crack arresting effect and reduction in initial porosity.
Polymerization of polar α-olefin with high activity and high syndiotactic selectivity catalyzed by scandium metal catalyst of fluorene coordination
Authors: Liu Yi , Liu Jia , Li Xiaofang
Published: March 2024

High functional poly α-olefin can be synthesized from polar α-olefin containing heteroatomic groups by coordination polymerization. These highly functional poly α-olefin materials can obviously improve the non-polar poly α-olefin materials, such as the appearance, printability, adhesion, rheology, compatibility with other polymer materials and blending properties to improve their added value and expand their industrial application range. In this paper, a series of polymer materials with potential application value were prepared with a catalyst of scandium fluorene Flu-Sc(THF)n (CH2SiMe3)2 to achieve high reaction activity (63.1×103g/(molcath)) and high selectivity polymerization (rrrr>99%) of polar α-olefin with different heteroatoms and different chain lengths.
Technological process for treating radioactive TBP/OK spent solvents
Authors: Ma Jing , Wang Ke , Li Meijiao , Liu Tiejun , Yang Cuiling
Published: March 2024

Tributyl phosphate (TBP) and kerosene (OK) spent radioactive organic solvents will be produced during the nuclear fuel reprocessing process, which may cause equipment corrosion by direct incineration. Therefore, additives need to be added to prepare a uniformly stable suspension. The amount of each raw material added during the preparation process and the stirring operation can have a significant effect on the performance of the suspension. In this paper, the influence of the amount of each raw material and the stirring rate on the emulsion formation, stabilization time, and fluidity of suspension is studied through different experiments to optimize the suspension formulation of the pyrolysis/incineration processes. The experimental results show that when the volume content of TBP was 30%~60%, the prepared suspension had excellent performance and could be used as the basic solution for suspension formulation. In contrast, when the volume content of TBP was more than 80%, the prepared suspension became less stable, the emulsion phase broke and settled, and the performance of the suspension was poor. When the volume contents of TBP were 30% and 60%, respectively, the DBP content was less than 0.26% and 0.6%, respectively, the Ca-P ratio was 1.25~1.75. Water content was 8~12%. The prepared suspension had great emulsion formation and fluidity. The viscosity and stability time meet the requirements with little secondary waste. The suspension can be applied in TBP/OK spent radioactive organic solvents pyrolysis/incineration reprocessing project.
Effect of nanoparticles on mechanical properties in composite coated materials enhanced by metal nanoparticles
Authors: Liu Xiaoqin , Peng Chenglong
Published: March 2024

The development of modern high-tech urgently needs high-performance materials with low elastic modulus, high yield strength, and large elastic strain performance. However, traditional metal materials lack the characteristics of combining the advantages of these high-performance materials. The metal nanoparticles, with super large elastic strain and ultra-high yield strength, enhance the incomparable superior performance of traditional single materials and have a wide application prospect in many modern high-tech industries. In addition, the nanoparticles will reunite in the collective, which has a certain impact on the mechanical properties of the composite coating materials. Several metal nanoparticles were selected as reinforcing materials and epoxy resin polymer as a matrix material to explore and analyze the influence of nanoparticles in the composite coating materials of metal nanoparticles. The hydrothermal method was used to enhance the properties of the epoxy resin polymer, disperse the epoxy resin, make the Huangyang resin composite coating, and study the effect of nanometer content on the mechanical properties of the composite coating. According to the research results, the appropriate amount of nanometers can optimize the performance of the coating of epoxy resin. When the number of nanoparticles added is 0.05%, the mechanical properties of the coating reach the best.
Molecular simulation of the effect of epoxy side chains on the microstructure and trap characteristics of the cured system
Authors: Chen Xingyu , Zhao Xiaoyang
Published: March 2024

Epoxy resin is widely used in power equipment as encapsulation insulation material, but its development and application are affected by its thermal stability, charge accumulation, and poor thermal conductivity. In this paper, epoxy resin’s properties are improved by side-linked grafting, and the microstructure and trap properties of epoxy resin that are grafted with Si-O covalent bond, C-F covalent bond, lipid ring structure, and benzene ring are studied by molecular dynamics method. The simulated structure shows that the epoxy side links do not affect the amorphous structure, but the molecular segment mobility, the number, and the free volume of hydrogen bonds will be affected by the system’s chemical structure. Among them, the introduction of bisphenol AF can increase the free volume of the system, improve molecular segments’ mobility, and affect the formation of hydrogen bonds. Molecular segments’ movement can be inhibited by Alicycles’ introduction. The hydrogen bond energy and hydrogen bond quantity of the system will be increased by the new hydroxyl group’s introduction. The system’s thermal conductivity is reduced by epoxy side links. The grafting of specific polar structures in the epoxy resin system can introduce deep hole traps and shallow electron traps.
Porous structure based on Fenton reaction-assisted chemical etching of commercial silicon powder and its application for electrocatalytic reduction of carbon dioxide
Authors: Li Junpeng , Wang Zi
Published: March 2024

Silicon-based porous nanocomposites are considered promising as electrode materials for the photoelectrochemical reduction of carbon dioxide. However, the high cost of raw materials and tedious processing for building nanostructures may not be conducive to large-scale industrial applications in terms of cost. Herein, we would like to introduce a porous structure prepared by Fenton reaction-assisted chemical etching of low-cost commercial silicon powder in the mixed solution of hydrogen fluoride and hydrogen peroxide. These porous particles are further decorated with silver nanoparticles to explore their feasibility for photoelectrochemical reduction of carbon dioxide. As shown by experimental results, this silicon-based nanocomposite is capable of catalyzing the conversion of carbon dioxide into carbon monoxide. The low cost of commercial silicon powder (~$3000/ton) compared with that of silicon wafers also renders this method potential and feasible for large-scale production of silicon-based porous materials.
Study on the wettability of the stainless steel pieces prepared by different methods
Authors: Zou Junchen , Chen Yingqi , Sun Xiaoquan , Huang Wenhao , Wu Qin , Chen Yongqiang , Yuan Dan , Zhang Zhao
Published: March 2024

With the increase in air quality problems derived from the emission of cooking oil fumes, the oil fume purifier was widely installed in household kitchens to eliminate the oil fume. However, because of the great adhesion of the oil, the elimination efficiency of the oil fume purifier goes down and its cleaning difficulty goes up. To solve the problem, four reagents were chosen to fabricate the amphiphobic surface by immersion and chemical vapor deposition. The results showed that the surfaces modified by alcohol reagent, organic fluorine group resin reagent, and heptafluorodecyl trimethoxysilane were only hydrophobic, while perfluorodecanoic acid-modified surface was amphiphobic and its contact angles for water and peanut oil were 138.3° and 125.5° respectively. Therefore, perfluorodecanoic acid could be used to prevent sticking and recycle the condensate of cooking oil fumes on the stainless steel surface of the oil fume purifier.
Cluster dynamics of proton irradiated RPV steel at room temperature
Authors: Wan Qiangmao , Tang Jiaxuan , Chen Lisha , Pang Jiangjun , Jiang Shaofei , Ding Hui , Shu Guogang
Published: March 2024

The life of reactor pressure vessels in nuclear power plants will be extended to 60 years, while the irradiation data of materials from commercial and experimental reactors are rare and expensive. There is an urgent need to solve how to accurately predict the changes in microstructure and mechanical properties of high-dose irradiated materials of RPV. The cluster dynamics method can be used to establish the relationship between nanostructure and macro properties and to study its evolution over a long period of years. Based on the average rate field theory, a cluster dynamics model was developed for the evolution of irradiated microstructure of RPV steel, which considers both homogeneous and heterogeneous nucleation of solute clusters. The model was successfully used to simulate the influence of the proton irradiation-induced cluster size and number density of RPV model steel with a low copper content at room temperature.
Multi-character selection for identifying superior oil palm cultivar using MGIDI
Authors: Sitepu A F , Yenni Y , Sujadi
Published: March 2024

Efficient selection methods are needed in oil palm breeding programs. Selection efficiency will increase if the selection is conducted on several characters simultaneously. However, the selection of segregating progeny is difficult because it is quantitative. MGIDI (Multi-trait Genotype Ideotype Distance Index) is formed based on Monte Carlo simulation to select superior progeny by considering several characters simultaneously. The aim of this study is to evaluate and identify planting materials with compact palm and good production traits using MGIDI. Data were obtained from 21 DxT palms planted at Dolok Sinumbah Plantation, PT. Nusantara IV Plantation, North Sumatra. The imbalanced North Carolina II mating design was employed to produce the materials for this study. The observed characters are the bunch analysis component and vegetative traits. Based on the factorial analysis (FA) results, these characters were grouped into three groups where FA1 contains ODM, OWM, HI, and DIAM. FA2 consists of BW and FB. FA3 consists of MF, OB, SF, KF, and LAI. Based on MGIDI, the selected superior progenies were DT11, DT6, and DT1. Aside from these genotypes DT15 was near the cut point, suggesting that it has an interesting feature. Positive selection gains (0.57-1.52) are obtained for the desired traits, and negative selection gains (-0.24 – (-0.88)) for undesirable traits. Visualization of the strength and weaknesses of each genotype can also assist breeders in decision-making to improve the progeny in the next breeding cycle.
Browning prevention of oil palm somatic embryos in the temporary immersion system with antioxidant mixture and modification of basal media
Authors: Sinta Masna Maya , Saptari Rizka Tamania , Riyadi Imron , Sumaryono
Published: March 2024

Browning on in vitro culture is one of the problems in somatic embryo regeneration that leads to growth inhibition and death of explants. This study aimed to prevent and control browning of oil palm somatic embryos (SE) in the Temporary Immersion System (TIS). The research was conducted in two stages; the first stage was applying an antioxidant mixture at concentrations of 20, 50, and 100 mg L-1 on the browning palm oil SE in TIS. The second stage was carried out by modification of the basal media, namely DF (control), MS, SM, and SMT. The explants used in experiment 2 were browning and fresh SE. The results showed that using 50 ppm antioxidants mixture increased the formation of new SE by up to 15 embryos per flask. Applying SMT basal media on browning SE could decrease browning rate sharply after two cycle cultures by up to 60% browning rate reduction. In this media, it was also seen that the number of new SE increased by up to 250 embryos and produced 15 germinants, while in control, only 60 SE and five germinants were formed. Whereas using SMT basal medium on fresh embryos could prevent browning and increase the formation of new embryos and germinants. In conclusion, using 50 ppm antioxidants can stimulate the formation of new embryos. Using SMT basal media could prevent browning and overcome the occurrence of browning in embryos by increasing the formation of new embryos and germinants.
In vitro antifungal activity of several organic compounds against Ganoderma boninense
Authors: Yusup Ciptadi Achmad , Eris Deden Dewantara , Mulyatni Agustin Sri , Pradana Mahardika Gama , Widiastuti Happy
Published: March 2024

Ganoderma boninense is the pathogenic fungi responsible for oil palm basal stem rot (BSR), one of the major diseases that can lead to plant death. Until recently, the most effective methods for controlling BSR disease were still in search. We tested several organic compounds that had the potential as fungicides for G. boninense, namely allicin, hesperidin, rutin, and polyphenol. The G. boninense used in this study was isolated from Bah Jambi, North Sumatra. The in vitro antifungal activity was tested using the media poisoning methods with 0.25%, 0.5%, 1%, 2%, and 4% concentrations with three replications. The growth capacity of treated G. boninense colonies was done using the Bavendamm test. The organic compounds showed different degrees of inhibition and increased with increasing concentration. Allicin was the most effective compound against G. boninense, with a 100% inhibition rate at the lowest concentration, followed by polyphenol. The G. boninense treated with allicin and polyphenol has neither grown nor produced a reddish-brown area underneath when reinoculated to a tannic acid-containing medium. This result indicates the treated inoculum has no growth capacity. Allicin and polyphenol showed high potential as active compounds of organic fungicide against G. boninense.
Enhancing the regeneration of TIS-derived somatic embryos of oil palm (Elaeis guineensis Jacq.) with CaCl2 and GA3
Authors: Saptari R T , Sinta M M , Riyadi I , Sumaryono
Published: March 2024

Micropropagation of oil palm through somatic embryogenesis (SE) technique provides clonal and uniform seedlings as high-quality planting materials for plantation. However, a problem associated with oil palm SE is the low regeneration rate of the somatic embryos. It was revealed that nutrient balance played a vital role in the success of SE regeneration. Therefore, a study was conducted to determine the balance between a macronutrient, calcium, and the germination-inducing hormone, Gibberellin (GA3) in enhancing the regeneration of the oil palm somatic embryos derived from the Temporary Immersion System (TIS). Treatments consist of various concentrations of CaCl2 (440, 880, or 1320 mg L-1) and enrichment of GA3 (2 or 4 mg L-1) applied into SE regeneration media, followed by the observation of regeneration rate and shoot tip necrosis after five weeks of culture. The study revealed that CaCl2 in the concentration of 880 mg L-1 was the best in stimulating oil palm TIS-derived SE regeneration. A higher concentration of GA3 (4 mg L-1) was needed in the first transition of SE from TIS into SE regeneration media in solid culture, while further SE-derived shoots development needed a lower concentration of GA3.
Recent Developments in F1 Hybrid Project
Authors: Nasution Olviyani , Iswandar Harry Ericson , Ramadhani Kurnia , Handoko Joko , Milani Ayu , Premana Angga , Djuhjana Jajan
Published: March 2024

London Sumatra (Lonsum) has continuously pursued the F1 hybrid project to produce the genetic and phenotypic uniformity of palms that highlight the exceptional qualities of the parents. Selection of haploid palms that have been duplicated by tissue culture techniques to become doubled haploid is an efficient method for producing highly homozygous palms. About 206 dura haploids and 47 haploid pisifera from different populations were obtained by abnormal seed and seedling screening. During this time, one of four dura-doubled haploids that produce normal flowers have proliferated. Due to the unavailability of doubled haploid pisifera, the potential of dura doubled haploid as a parental candidate was tested by crossing it with highly homozygous diploid pisifera (>80%). The offspring are referred to as semi-hybrids and are currently in an immature state. Going forward, the F1 hybrid project will cross doubled haploid dura and pisifera while continuing to monitor the potential of semi-hybrids.
Geospatial technology on road, terrace and planting point for oil palm cultivation in hilly terrain
Authors: Totok S , Dzulfansyah D , Hermanto A , Tey S H
Published: March 2024

One of marginal area for oil palm cultivation is on hilly terrain, which pose various agro-management problems start from planting preparation, during oil palm growth/maintenance and up to the harvesting and transporting of the fresh fruit bunches. Geospatial technology was used to help designing road system with focuses on 1) road gradient of less than 7°, 2) road density of less than 200 m/ha and 3) carry distance of about 100m along the terraces. Commercial trial in Pelalawan Riau showed that the design can be implemented resulting average road gradient of 4.7°, road density of 234 m/ha and average carry distance of 143m. Geospatial technology was also used to help designing terraces where digital terrain model was used to produce suitable rajah line location. On planting point, improved Gawthorn and Violle method was introduced incorporating geospatial analysis in detection of potential etiolation areas. The method produced stand per ha of 142 palm/ha (and 145 in commercial) with minimized potential etiolation area to 6%.
Comparative incidence of Ganoderma basal stem rot and upper stem rot disease in oil palm in relation to soil type and geographical distribution
Authors: Hendra H , Haryadi D , Sidhu M , Samosir Y , Tan J S
Published: March 2024

The greatest danger to oil palm sustainability in Indonesia is posed by basal stem rot (BSR) and upper stem rot (USR). However, information on their comparative incidence in relation to soil types and geo-distribution remains scarce. As such, data from annual surveys carried out over 95,000 ha of first-generation oil palms planted in Asian Agri estates was reviewed and analyzed. The highest infection levels occurred in North Sumatra, followed by Riau and Jambi. Likewise, infection levels were highest in peat (24.79 palms/ha), followed by alluvial (13.41 palms/ha), volcanic (7.25 palms/ha), and inland (0.07 palms/ha) soil types. Averaged over three provinces and all four soil types, infection due to USR was more dominant than BSR, comprising 52.3% and 47.7%, respectively. Molecular assays of infected tissue confirmed that both BSR and USR were caused by the genus Ganoderma with the major species being G. boninense. Longitudinal dissections of oil palm trunks infected by USR indicated no infection connectivity with the basal portion of the trunk, unlike BSR, where the infection is through root contact. Transmission through basidiospores is likely to play an essential role in USR epidemiology. Understanding pathogen distribution, species identity, and its transmission epidemiology are prerequisites to control diseases more effectively.
Breeding using parents of restricted origins
Authors: Nur F , Forster B P , Caligari P D S
Published: March 2024

Breeding using parental lines of restricted origins (BPROs) is a term used to give a description of populations that can be traced back to specific origins. Breeding material available at Verdant is obtained via Dami Oil Palm Research Station (Papua New Guinea). BPROs have been conserved and, or developed independently by selfing, sib crossing, and inter-progeny crossing within the BPRO. Deli Dura is a well-known female breeding population along with the famous AVROS male lines. Other breeding materials being conserved, targeted, and developed by Verdant include: Calabar, Sibiti, and Ekona materials, plus other breeding materials initially received from the former Binga Research Station, Democratic Republic of Congo. Verdant is also exploiting several lines of La Mé material. Breeding using marker-defined genotypes is deployed to target breeding using selected parents. Progeny and palms with distinct genetic variation and complementary traits can be identified by in-depth genotyping (e.g., Diversity Array Technology, DArT marker analysis) – PCoA plots generated from DArT show distinct diversity clusters within and among breeding materials. AVROS and Deli Dura breeding materials are separated by relatively large genetic distances, which may account, in part, for their success in producing commercial Teneras. The PCoA plots also show that Deli Duras are distinct from Dabou and Angola Duras. Variation in Pisifera germplasm is associated with allelic variation at the SHELL gene (Sh). Various Sh allelic combinations are found in the BPRO materials: A/A, 1/1, and 8/8.