Influence Of Different Positions Research Articles

Experimental study on grinding process of Al-Mg2Si aluminum matrix composites

As an aluminum-based reinforcement, Mg2Si particles have excellent properties such as high hardness, high melting point, and high elastic modulus compared with other reinforcements and are widely used in aerospace and automobile fields. However, there is little research on the cutting mechanism of this material. In order to explore the surface grinding mechanism of Mg2Si/Al composites, Grinding simulation of low-volume fraction Mg2Si/Al composites was carried out by ABAQUS, and the influence of different positions of matrix and particle removal on the surface quality of Mg2Si/Al composites was expounded. The plane reverse grinding test was carried out by using CBN (boron nitride) grinding wheel. The L16(43) orthogonal test and three groups of single factor tests were designed. The orthogonal results show that the linear velocity of the grinding wheel has the greatest influence on the surface roughness, and the feed rate and grinding depth are significantly smaller. The range analysis shows that the optimal grinding parameters are: vs = 35 m/s, vw = 0.75 m/min, ap = 0.015 mm. The regression equation for surface roughness was established by using MATLAB. The single factor results show that the surface quality is obviously improved by increasing the linear velocity of the grinding wheel and reducing the feed rate and grinding depth through the observation of the morphology of the processed specimen. The analysis results show that defects such as pits, protrusions, burrs, and a small amount of fish-scale-like on the machined surface are mainly caused by the linear velocity of the grinding wheel, the pulling force of the grinding wheel, and the adhesion of the debris. The defects such as particle micro-cracks, particle pull-out, and matrix cracking on the subsurface, are mainly caused by the compressive stress of the grinding wheel and the stress concentration of the particles. The research results have guiding significance for future composite material cutting research and actual cutting processing.

Numerical simulation of the effect of coaxial and cross-axis injection modes on pulverized coal combustion in the raceway of blast furnace tuyere

The aim of this study is to investigate the influence of the angle of the pulverized coal (PC) injection lance on the combustion characteristics of fuel in the raceway of blast furnace tuyeres. Using FLUENT software, a Euler-Lagrange three-dimensional numerical model was constructed to analyze the influence of different positions of blast furnace tuyere coal powder injection lance (coaxial and cross-axis) on key parameters such as temperature distribution, gas flow, and combustion efficiency. The results demonstrate that adjusting the angle of the injection lance significantly modifies the average and peak temperatures in the raceway, while the composition of gas components remains relatively stable. When the injection lance angle is 10°, the average temperature and peak temperature in the raceway are 2294 K and 2747 K, respectively. When the injection lance angle is 12°, the combustion efficiency of the PC reaches 80.8%. This study reveals the significant impact of the injection lance angle on the combustion process. Especially at an angle of 12°, the combustion efficiency of the blast furnace significantly improves. With coaxial injection, the combustion rate increases as the distance between the injection lance tip and the tuyere increases. This paper is instructive for the optimization of the blast furnace combustion system, which improve fuel utilization efficiency and reduce environmental emissions. This paper provides practical recommendations for adjusting blast furnace operational parameters, offering insights for achieving more efficient and environmentally friendly industrial production.

Influence of the configuration of metal sensing layers on the performance of a bimetallic (Ag–Cu) surface plasmon resonance biosensor

Bimetallic surface plasmon resonance (SPR) sensors have the potential to overcome the drawbacks of individual metals, but the effect of the configuration of the two metallic layers on the performance of the sensors has not been explored. This study examines the influence of different positions of a thin layer of silver in relation to a copper layer on the sensitivity of such a bimetallic SPR sensor. The design of this configuration aims to improve the SPR reflectance curve and strengthen the evanescent electric field to improve the sensor efficiency. Our findings indicate that, by optimizing the architectures of SPR sensors and using a silver–copper bimetallic structure, we can achieve superior performance compared to devices that utilize only silver or copper. The optimized Ag (5 nm)/Cu (55 nm) sensor design, with the best sensitivity of 299.09° RIU−1, can detect a change of 0.43°/(g dl−1) for hemoglobin in blood, 0.35°/(g dl−1) for glucose in urine, and 0.1°/(%) for methanol in ethanol. We also demonstrate the importance of signal quality by introducing two new parameters that offer a better quantitative indication of the efficiency of a sensor than is obtained by using only sensitivity.

Performance of Reflective Film on the Light Environment of Chinese Solar Greenhouse

To enhance the utilization of solar energy in Chinese solar greenhouses (CSGs), a new method for optimizing the internal lighting environment of CSGs using reflective films is proposed. The influence of different positions and angles of reflecting film on solar radiation in greenhouses was studied, using the solar radiation on the inside surface of the CSG as an evaluation index. According to the findings, total solar radiation increased by 5.33% when the reflective film was positioned on the north roof at an angle of 0°. The light interception on the north wall decreased from 7.91% to 10.54% when the angle was raised from 15° to 25°. The crop canopy was not significantly affected by the reflective film’s various placements and angles, and the benefits of additional light were insufficient to compensate for the drawbacks of crop shading. This result provides a theoretical basis for the application of reflective films in relevant agricultural facilities. Reasonable installation of reflective film in the greenhouse can increase the light interception of plants inside the greenhouse and further increase the income of farmers.

High-velocity impact damage and compression after impact behavior of carbon fiber composite laminates: Experimental study

In this paper, the impact resistance of carbon fiber/resin composite laminates with a thickness of 2.5 mm at different impact velocities, angles and positions was investigated experimentally. In the process of high-velocity impact, fiber shear failure and tension failure are the main failure modes. When the impact velocity is 300 m/s, the fiber tension failure and matrix compression failure under oblique impact are more than that under normal impact, and the energy absorption of laminates is also lager than that under normal impact. The ballistic limits, energy absorption and delamination area of the center and edge impact of laminate are similar. In addition, the CAI tests are conducted to study the influence of different positions on the residual compressive strength of laminates after high-velocity impact, and the fracture loads and failure modes of two impact positions are quite different. The failure modes of the center impact laminate are main buckling failure, and the failure modes of the edge impact laminate are compression failure near the bullet hole side of the fixture and buckling failure near the center of the laminate. The research results can provide a reference for the residual strength of laminates after impact at different locations in practical situations.

Analysis and Research on Lightning Inrush Wave Overvoltage in EHV GIS Substation transformation project

When lightning intrudes into the over-voltage in the 500 kV substation, the lightning wave will be introduced into the substation along the line, which will seriously affect the insulation level of the equipment. In this paper, firstly, the working principle, characteristics, and lightning current simulation of the ZnO arrester are described. Then, the electromagnetic transient program (EMTP-ATP) used in a 500 kV GIS substation carried out the simulation research to the lightning over-voltage, specifically studied the lightning protection effect of metal oxide arrester, compared the lightning over-voltage under the different lightning locations and operation mode, and calculated the 500kV GIS Substation under the single in single out operation mode, 500kV. The influence of different positions of lightning arresters in GIS on the magnitude of lightning over-voltage and the lightning over-voltage on the substation equipment in GIS is also described.

Analysis of the Notch Filter Insertion Position for Natural Frequency Vibration Suppression in a Magnetic Suspended Flywheel Energy Storage System

The composite material flywheel rotor of a flywheel energy storage system (FESS) has a low natural frequency. When the system suffers from noise interference, the magnetic bearing generates a force with the same frequency as the natural frequency and causes vibration to occur. Thus, it is necessary to suppress the natural vibration of the magnetic suspended (MS) FESS. The LMS adaptive notch filter is generally adopted for vibration suppression. The vibration suppression performance of the system is different when the insertion position of the notch filter is different. This paper analyzes the influence of the notch filter in different insertion positions of the control system. Through the transfer function from noise to magnetic bearing force, theoretical analysis of the influence of different positions of the notch filter is performed. Corresponding experiments are performed in a 500 kW MS FESS prototype. The theoretical analysis is verified experimentally.

Study on the storage time of a cold box based on conduction-convection-radiation coupling

A theoretical model coupling with conduction-convection-radiation was proposed to calculate the storage time of a cold box. The experimental and numerical results at amounts and positions of a refrigerant were used to verify the theoretical model of the cold box. The numerical results at various ambient temperatures were also used to verify the theoretical model. The theoretical model analyzed the influences of different positions of the refrigerant and the thickness of the cold box on the storage time. The determination value K was proposed. Results show that the maximum error between theoretical results and experimental and numerical results was 2.26 %, indicating that the theoretical model of storage time is consistent with the experimental and numerical results and the theoretical model can replace numerical simulation to reduce time. The storage time from the refrigerant position from bottom to top gradually decreases. The best thickness of the cold box was 27.5–38.75 mm, which was independent of the positions of the refrigerant, ambient temperatures, materials of the cold box and the refrigerant, and the sizes of the cold box.

Improved generalized regression neural network for quantitative analysis of crude oil density by gas chromatography

在油气勘探开发领域,快速识别储集层原油性质对于工程技术人员有非常重要的指导意义。地球化学录井技术是用于判断储集层原油性质的常规手段,能为储集层综合评价提供专业认识。该文研究了地化录井中的岩石热解分析和气相色谱分析的原理,提出了一种利用色谱谱图对原油密度进行定量分析的新方法,再结合原油性质密度划分标准,可快速判断储集层原油性质。首先使用计算机图像处理软件对色谱图进行标准化和归一化预处理,并分析了岩石热解气相色谱谱图的曲线特征规律,提出了岩石热解气相色谱谱图的特征参数提取方法,将色谱图转换为特征参数矩阵。其次,研究了3种人工智能预测分类模型,为了适合该实验对储集层原油密度的预测,对其做了部分优化改进,利用元启发式优化算法(麻雀搜索优化算法)对广义回归神经网络的超参数进行了优化,提高了模型的精度和收敛速度。最后,通过现场获得的气相色谱图样本对各模型进行训练并验证,综合对比3种模型预测的结果,发现基于麻雀搜索算法优化的广义回归神经网络预测模型效果最佳,模型稳定,预测密度误差小,可泛化能力强。该研究所提出的方法能为储集层的综合评价研究和现场施工提供可靠的数据支撑。

Investigation of inter-stage passive flow control for turbine performance improvement on regulated two-stage turbocharger

Abstract The flow field coupling effect between the HPT (high pressure turbine) and LPT (low pressure turbine) introduces a particular flow structure to the two-stage turbocharging system. Compared to the isolated turbines, the performance of these two connected turbines will inevitably be affected by each other. However, in the open state of the bypass valve, the influence of the bypass flow on this flow field coupling effect is still unknown. In this study, the inter-stage performance interaction of regulated two-stage turbocharger was investigated through the three-dimensional numerical method. With the bypass valve open, the influence of different positions of the bypass branch on the inter-stage coupling effects is investigated. The results manifest that the different positions of the bypass branch significantly change the performance of low pressure turbine and the flow interactions within the inter-stage. When the bypass branch is on the right, the LPT efficiency improves by approximately 2.2%. The detailed flow field analysis of the inter-stage pipe, volute and rotor is conducted to reveal the flow mechanism behind the inter-stage interactions. Based on this investigation, a new passive flow control scheme is proposed to ameliorate the swirling flow at the LPT inlet and improve the performance of LPT.

Measurement and analysis of machining induced tribological characteristics in dual jet minimum quantity lubrication assisted turning of duplex stainless steel

In this work, the sustainable machining approach is promoted by implementing the dry and minimum quantity lubrication (MQL) cooling conditions in the turning of duplex stainless steel. Initially, the turning experiments were performed under dry as well as MQL conditions and then, the influence of different positions of MQL nozzles on tribological and machining performance of 2205 duplex steel was investigated. The cutting parameters were kept fixed and the performance is evaluated in terms of surface roughness, micro-hardness, energy consumption, tool wear, machined surface microstructure and chips morphology. The results demonstrated that the highest average surface roughness values were obtained under dry conditions, with a value of 2.20 µm while MQL (flank + rake directions) produces the lowest surface roughness value of 1.55 µm with an improvement of 30%. Moreover, dual-jet MQL gives the lowest energy consumption (229 kJ) and tool wear (0.15 mm) with 23.67% and 52.38% enhancement, respectively.

Numerical study on surface-heterogeneity-induced anisotropic impact dynamics of droplet

Droplet impact on flat surfaces with heterogeneity is expected to trigger unusual impact dynamics, such as anisotropic spreading and directional rebounding, which in turn could be utilized in the control of droplet motion in many industrial processes. The present work illustrates a numerical study on droplet impact on a flat superhydrophobic substrate coated with a heterogeneous rectangle area, the influence of different positions and wettability of this heterogeneous area on the impact dynamics is investigated. The simulation results show the wettability of the heterogeneous area can impose significant influence on the spreading, retracting, and bouncing processes, especially when the heterogeneous area is located on a site other than the initial contact point, the bouncing of droplet is more likely to happen, and the contact time also becomes shorter. The clear pictures and analysis of the impact dynamics could advance the knowledge of how to control droplet motion by surface coatings.

Indonesia’s Climate Change Policies: Under the Tug of Domestic and International Influences

Paris Agreement with its ‘bottom-up’ approach is an attempt to address climate change problem. The Parties of the Paris Agreement decide their own policies in the national scope and present it as pledges in the form of Nationally Determined Contributions (NDCs). I explore the evidence to the shaping of the climate change policies in Indonesia, mainly regarding NDCs and the engagement of actors behind the shaping of that pledge. The main question is which actor or combination of actors in terms of domestic and international interests actually influenced and shaped Indonesia’s NDCs? This article aims to give practical evidence regarding the influences of different positions among competing interests through negotiation. In terms of Indonesia’s policymaking, this study is hoped to foster a viewpoint for the sake of acceptable practices to intensify policymaking preferences. In this literature review Liberal Intergovernmentalism propositions were used in examining the dynamics at the domestic level as well as transnational/regional negotiation and interdependence. I also used multiple sources from other studies and governmental documents in the analysis of this qualitative research. As a result, some evidence were found, showing the influence of domestic actors such as Local and Environmental NGOs, CSOs, public perceptions to certain extent, and insignificant influence of business groups. I also found that the transnational institutions and developed countries have impacts on Indonesia’s CC policy framework, funding provision and the balance between mitigation and adaptation.

Simulation Study on the Influence of Fire Partition on Curtain Wall Temperature in Super High-Rise Buildings in China

The poor fire resistance characteristic of super high-rise curtain wall makes the curtain wall design one of the main approaches to improve its capacity for prevention and control over fire and smoke spread. The propagation of smoke leads to the increase in the temperature of the curtain wall on the upper and lower floors of the fire floor and consequently leads to glass fracture and other serious consequences. Current codes have control over fire resistance performance and size of fire partition materials but do not include requirements on the position of curtain walls on floors. By changing the position of fire partition in curtain walls, the paper carries out three comparative simulation experiments on two forms of fire partition: spandrel and fire prevention cornice. Besides, PyroSim is used to calculate the comparative simulation of fire and smoke spread and obtain the data on temperature variation nephogram and monitoring points in the center line of glass curtain walls during different fire scenarios, so as to discuss the influence of different positions of spandrels and fire canopy on fire hazard and smoke. This study finds out the following: fire canopy can better prevent the longitudinal spread of fire smoke than spandrels. The fire canopy above spandrels can reduce the flue-gas temperature. The higher the spandrels above floors, the faster the temperature of the central lines of glass curtain walls above fire floors reduced. However, the higher the spandrels above floors, the more uneven the distributions of high-temperature regions and low-temperature regions, thus leading to the increase in horizontal temperature differences of glass panels. This research conclusion can be taken as a reference for fire protection design of super high-rise glass curtain wall.

Binding Site Effect in Metal‐Organic Frameworks for Property Regulation of Metal Nanoparticles

Metal nanoparticles (MNPs) supported on metal–organic frameworks (MOFs) have exhibited excellent performance in various catalytic reactions. As a class of crystal catalysts, the roles played by MOFs different positions in regulating the MNPs properties are distinct. It is therefore meaningful to clarify the influence of different positions of MOFs on MNPs to help reveal the structure–activity relationship. However, the random dispersion of MNPs in the MOFs matrixes is usually an obstacle existing in the traditional preparation methods. Herein, a facile strategy is developed to precisely control the MNPs growth behavior on the target binding sites of MOFs. The MNPs on edges of MOFs show significantly improved hydrogen evolution reaction performance in comparison to those on the planes of MOFs, mainly because the electronic structure of MNPs is regulated by special interface originating from MNPs growth on the edges of MOFs, which provides high density of unsaturated copper ions. The effect of different binding sites of MOFs on MNPs properties is clarified, which is highly desired for fine‐tuning the structures and properties of the MOF composites.

DM Interference Propagation Mathematical Modeling in SiC Wirebond Multichip Power Module

In this brief, a novel differential-mode (DM) interference propagation mathematical modeling method based on parasitic inductive coupling theory for SiC wirebond multichip power module (SWMPM) with adjacent decoupling capacitor is proposed. Based on the proposed model, the strong and weak inductive coupling theory of DM interference equivalent circuit is proposed. And the influence of different position of decoupling capacitors on DM equivalent current is mathematically analyzed. A custom-made 1.2kV 160A power module based on DM interference optimized layout is built. It is compared with a commercial SiC power module, which can verify the feasibility and validity of the theoretical analysis.

Effects of dyes on tensile strength and thermal damage of laser biological tissue soldering

Laser tissue welding is a hot issue in surgical research due to its advantages of non-contact, instant water tightness, no suture removal, no rejection and anti-infection. However, the contradiction between strength and thermal damage has not been solved completely. The addition of dye can solve the problem. Therefore, in order to improve the welding strength and quality, this paper studies the influence of different position and concentration of dye on the welding strength and determines the optimal concentration and applied position. Two kinds of flux were prepared, which were based on bovine serum albumin solution and stained with indocyanine green and methylene blue respectively. Comparing the welding effect of flux, the indocyanine green group is more remarkable. When the concentration of indocyanine green is 2.0 mg/mL, the maximum tensile strength reaches 19.32 ± 1.22 N/cm2, which is significantly higher than that of the control group without flux. When the flux is applied to the front side, the tensile strength is higher than the reverse side group. Two kinds of flux can effectively reduce the thermal damage. Our study demonstrates that indocyanine green and methylene blue are significant organic chromophores in laser welding process, which can promote the efficiency of photo-thermal conversion, improve welding strength and reduce thermal damage.

Research on Influence of Angle of Deflector on Air Flow in Spray Area Based on Numerical Simulation

The movement and distribution of the airflow field of the sprayer are very important for the distribution and penetration of the droplets. It is the focus and difficulty of the research to find the airflow field distribution of the fan outlet that matches the parameters of the canopy of the fruit tree. In order to study the influence of the angle change of the deflector of the orchard air-driven sprayer on the three-dimensional spatial distribution of the external air velocity field, this paper numerically simulated the external flow field based on computational fluid dynamics. The spray requirements of different fruit tree crown shapes were analyzed. The ICEM CFD software was used to model the external flow field. In order to improve the calculation efficiency, the model was divided into mixed grids. The k-ε turbulence model and Fluent solver are used for numerical solution. The flow fields of different deflectors are analyzed, and the influence of different positions and different sizes of deflector angles on the external flow field is determined.

The Duty of Retreat in Self-defense Law

It is diffi cult in determination of self-defense that Whether the defenders have the duty of retreat in the face of the unlawful infringement which can be avoided. The continental theory stands that defenders do not have to retreat, and China takes a similar position. In the history of Anglo-American law, the principle was the obligation of affi rmative withdrawal. The SYG bill passed by several U.S. states since 2005 totally denies the retreat duty in defense, but the SYG bill faces controversy due to the 2013 trial of Trayvon Martin in Virginia. Based on the social effect of case law, the American academic research on the duty of retreat in self-defense is to investigate the infl uence of different positions on social security. In our judicial practice, self-defense has a results-only situation, which limits the authorized defense right. However, the recognition of self-defense should not be overcorrected and go to the other extreme. The defender who uses the fatal defense means should be obliged to retreat. Under the premise of the possibility of retreat, the principle of balancing and proportion of legal interests restricts the establishment of self-defense.

Electrodes Optimization of an Annular Flow Electromagnetic Measurement System for Drilling Engineering

The early monitoring of downhole overflow can be effectively realized by the downhole annular electromagnetic flow detection system. In order to improve the accuracy of the electromagnetic measurement system of downhole annular flow, it is important to optimize the excitation system and electrodes of this system. This research focuses on the optimization of the electrodes for the electromagnetic measurement system of downhole annular flow, whose excitation system has been optimized. First, the basic principle of electromagnetic measurement of downhole annular flow is analyzed. Then, the influence of different positions of the four-point electrodes on the virtual current distributions is analyzed, and the optimum electrode positions and distributions are introduced. On this basis, the influence of shape and size of the large electrode on virtual current density distribution is analyzed. Based on the theoretical study of the influence of electrode on virtual current density distribution, taking hemispherical electrodes and arc electrodes as examples, this paper optimizes hemispherical electrodes and arc electrodes with different shapes and sizes by using finite element simulation method, and proposes three indexes to evaluate the annular virtual current density distributions when the electrodes of different shapes are used. The optimum parameters of shapes and sizes of the hemisphere electrodes and arc electrodes under specific structures of the downhole annular electromagnetic flow measurement system are obtained. This research has great significance for the optimization of electrodes in the downhole annular electromagnetic flow measurement system, and can also be used as reference for the electrode optimization of the traditional electromagnetic flowmeter.