Experimental Study Of Parameters Research Articles

Establishment of a Digital Laminography facility at the Malaysian Nuclear Agency

Digital Laminography (DL) is a technique that enables the estimation of indication depth from a set of digital projection radiographs. It allows the engineers or researchers to visualize and measure the depth from the object’s surface. The technique applies to welded components and non-metal applications such as composite materials. The technique also allows users to understand engineering problems and further analyze the cause of failures. Malaysian Nuclear Agency is pursuing the building and establishment the DL system at its facility. A gantry is designed to hold a 225kVp X-ray tube that is mechanically moved slowly. A 100 µm pixel size Digital Detector Array (DDA) is used to capture the images. This paper highlights simulation and a preliminary assessment to understand the physics and appropriate steps to build a DL system. It discusses the simulation and experimental study of exposure parameters and setup by digital radiographic testing (RT-D) of known imperfections of a welded steel plate before performing the DL measurement. The radiographic images and their achieved contrast sensitivity and image quality are analyzed according to ISO 17636-2. The results of simulations and experiments demonstrate a good and consistent ability to measure the depth and extension of the reconstructed imperfections within ± 1 mm regarding the actual size and position.

An ANN based modelling, forecasting, and experimental study of emissions and performance parameters running on microalgae biodiesel-nanoparticles blended fuel

An ANN based modelling, forecasting, and experimental study of emissions and performance parameters running on microalgae biodiesel-nanoparticles blended fuel

Experimental and kinetics of the oxidation of ammonium sulfite by hydrogen peroxide in ammonia flue gas desulfurization

ABSTRACT The oxidation of ammonium sulfite obtained from ammonia-based flue gas desulfurization by hydrogen peroxide in aqueous solutions was studied using a stirred reactor. An experimental study of the kinetic parameters of the oxidation process was investigated in the pH of 4.2–5.2 at 25–50°C. r = k 3 H + HS O 3 − H 2 O 2 is valid at sulfite concentrations of 10−4 mol/L for the pH range 4.2–5.2. At 298K and pH of 5.0, third-order rate constant k 3 was found to be (6.9 ± 0.21)×107 (mol/L)−2s−1. When the concentration of sulfite is 0.01 mol/L, the reaction first-order with respect to sulfite and hydrogen peroxide, and the second-order reaction rate constant at pH of 4.2–5.4 is lg k 2 = − 1.0135 pH + 7.4862 . Activation energy of E a = 32.26 kJ/moL. Kinetic data were compared with previous studies. A semi-empirical formula can express the effect of ionic strength on k 3. The kinetic data of ammonium sulfite oxidation with hydrogen peroxide have potential applications in the wet ammonia desulfurization process.

Experimental study and statistical analysis of system performance parameters of a household freezer

The present research comprehensively examines the influences of different input variables, such as cabinet load level, ambient temperature, relative humidity, door opening time and day, on the output parameters of frosting amount, recovery time, and total energy consumption of the upright domestic freezer following the door opening operation. Moreover, a holistic statistical methodology, which is known as the GLM-ANOVA, was implemented for determining the parametric experimental results. Meanwhile, the effects of binary interactions between the input factors on the output parameters were extensively evaluated using statistical methods. As a consequence, the amount of frost increases with an upward gradient as the load level within the cabinet escalates from 25 °C to 32 °C. Both the duration of door openings and the relative humidity level have a double impact on the frosting. Moreover, the duration required for the system to recover from half load to full load more than doubles with an increase in ambient temperature from 25 °C to 32 °C. On the other hand, at an outdoor temperature of 25 °C, the recovery time demonstrates a close to linear relationship with the load level of the cabinet. Furthermore, the duration of door openings and the load capacity within the cabinet are considered two important factors that simultaneously influence the daily energy consumption. The infiltration of ambient air into the freezer compartment and the presence of moisture in the air substantially increase the energy consumption, especially when the relative humidity fluctuates between 30 % and 65 % and the door opening duration stretches from 10 to 20 s, respectively.

Experimental study and correlation of critical parameters for three binary mixtures containing R290 and hydrofluoroolefins

The mixtures of R290 (propane) and R1234yf (2,3,3,3-tetrafluoroprop-1-ene), R1243zf (3,3,3-trifluoropropene), or R1234ze(E) (trans-1,3,3,3-tetrafluoropropene) could be potential alternatives for high global warming potential (GWP) refrigerants hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs). Obtaining the critical parameters of mixtures is crucial for establishing thermodynamic models, evaluating the highest operating temperature of refrigerants, determining the phase envelope, and confirming the starting point of the Widom line. However, few studies have been made on their critical properties. In this work, the critical properties of three binary systems containing R290 + R1234yf / R1243zf / R1234ze(E) are obtained experimentally with a metal-bellows volume apparatus. The critical state is judged by direct visual observation of critical opalescence and the recurrence of the vapor-liquid phase interface. The extended total uncertainties for the mole fraction, critical pressure, critical temperature, and critical density were below 0.004, 21 kPa, 50 mK, and 0.6 % (k = 2, 0.95 confidence coefficient), respectively. Experimentally obtained critical data are correlated by the Modified Wilson method and the Redlich–Kister method. The critical parameters of the R290 + R1234yf, R290 + R1243zf, and R290 + R1234ze(E) mixtures are predicted using the Correlated Modified Wilson (CMW) method, He et al.’s method, and the Modified Extended Chueh–Prausnitz (MECP) method. The correlated curve and predicted outcomes are employed for comparison with this work's experimental results. Meanwhile, the critical parameters data obtained experimentally are contrasted with the value of REFPROP 10.0 and other open literature. The fitting and prediction curves somewhat agree with the experimental results.

Swirling flow and heat transfer in a pipe: Decay and transition to axial flow

This paper describes an experimental study of heat transfer, local and total swirl flow parameters in the pipe 80 mm in a diameter and 150 diameters long. The pipe consists of 12 separate pipes of different length, connected to each other using 20 mm ring spacers. These spacers were also used to provide the flow and heat transfer measurements. Overall, eight blade-type swirl generators with central body and profiled according to the power low, are installed at the pipe inlet. The actual swirl intensity S of swirl generators is ranged from 0.38 to 1.29. The profiles of mean axial and tangential velocity, surface heat flux, swirl flow angle, static and total pressure, flow and surface temperature are measured. A few novel scientific results and equations are obtained, including the axial and tangential speed maximum, axial and tangential momentum flux, swirl number decay and energy loss transformation. The common link between the local and total swirl parameters, one-valued correlation between tangential and axial velocity were obtained. The results, presented in the paper led to the conclusion that transition from swirling to axial flow occurs at S ≈ 0.19 in terms of the heat transfer decrease, but at S ≈ 0.10 – in terms of the energy loss reduction.

Numerical and experimental study of thermography parameters for inspection of composites repaired by CFRP patches

ABSTRACT Considering the ever-increasing importance of composite patches applied to repair or reinforce composite structures, radical health monitoring of these patches seems inescapable. Thermography method is one of the most influential non-destructive methods applied to inspect the repaired structures. Since there are many parameters influencing defects detection in repaired composite structures, extracting the most influential method to determine these parameters is significantly important. In the present study, a repaired carbon fiber reinforced plastic (CFRP) composite structure having defects of different dimensions, types and features located in different depths, is investigated by experiment and finite element simulations to assess the influence of the experimental parameters, like the thermal excitation pulse duration and the best image frame. In thermal simulation, two criteria, maximum thermal variations versus time and path length, are developed to derive the most optimum heating duration and the best thermal frames. The obtained results are validated through defining direct and diagonal paths passing through defects demonstrated on thermography images and thermal map images. The average error of thermal variations on different paths displayed on thermography and simulation images is less than 4.5 percent which confirms the correspondence of obtained results of both mentioned methods.

Experimental and numerical study of structural parameters on the heat transfer performance of submerged cooling system

Immersion direct contact cooling effectively transfers heat from electronic components to a cooling solution without additional thermal resistance, due to its high energy density, low power consumption, system simplicity, and integrated thermal management for electronic devices. Current scholarly research on immersed structures predominantly focuses on surface temperature effects, with a scant investigation into internal flow and temperature field distributions concerning boundary layers. This study addresses structural optimization in immersion cooling systems, employing experimental and simulation methods to elucidate the thermal mechanisms by which structural optimization impacts the performance of chip immersion cooling systems. The research examines the impact of panel spacing and liquid level height on the thickness of velocity and thermal boundary layers, as well as the combined effects of natural and forced convection under three distinct cooling modes. Analysis reveals that heat pipe immersion cooling can reduce the heat source junction temperature to 40.7 °C under a 60 W power dissipation, a 47.2 % decrease from the bare heat source temperature. Reducing panel spacing disrupts the thermal boundary, enhancing forced convection and lowering the junction temperature by up to 10.1 % (6.5 °C). As liquid level height increases, the junction temperature initially decreases and then rises, with an optimal height of 175 mm for the best overall heat transfer effect. At low flow velocities (0.04 m/s), the vertical buoyancy-induced flow velocity at the heat source surface (24.2 × 10-6 m/s) exceeds the horizontal forced convection velocity (0.78 × 10-6 m/s), indicating that buoyancy changes due to density differences are significant and must be considered.

ДОСЛІДЖЕННЯ ТЕХНОЛОГІЧНИХ ПОКАЗНИКІВ РОБОТИ ВІБРАЦІЙНОГО ГРОХОТА З ЕЛАСТИЧНИМИ СИТАМИ

In the metallurgical branch of industry, the problems of separation according to the given size - screening of the original metallurgical raw materials, in particular coke, are relevant. This ensures high-quality operation of the technological equipment of blast furnaces and supply of blast furnace coke of regulated size. In this regard, research is constantly being conducted and the development of new methods of screening and modernization of devices to improve the performance of vibrating screens continues. The purpose of the scientific work: an experimental study of the technological parameters of the vibration screen with elastic sieves. The paper gives a description of the laboratory vibrating sieve with an elastic sieve, which is used in the research. An experimental study of the technological parameters of the screening process of the vibrating screen was carried out and the dependence of the technological indicators on the parameters of the vibrating screen was constructed. It has been shown that the highest screening efficiency is observed at oscillation frequencies in the range of 22-27 Hz. At these frequencies, the efficiency indicators of the screening process vary between 78-90%. A change in the value of the specific load from 10 t/(h m^2) to 16 t/(h m^2) causes a gradual decrease in the screening efficiency from 90% to 65%.

Optimization and Experimental Study of Operation Parameters for Fertilizer Injection Drilling Device Based on Discrete Element Simulation

In addressing the challenges of high energy consumption and low efficiency in fertilization borehole drilling for clayey soils in southern orchards, this study utilizes the Discrete Element Method to establish a simulation model for clayey soils. Through this approach, we identify an optimal set of operational parameters that significantly reduces energy consumption. By utilizing simulation technology to model the drilling process, we analyzed the impact of rotation speed and feed rate on the torque and resistance of the drilling apparatus. Initially, this paper describes field measurements of particle parameters in soils from southern orchards. Subsequently, utilizing the Discrete Element Method and particle contact theory, we established a simulation model to represent the interactions between soil and soil, as well as soil and auger in the soil environment of the southern region. For the Southern orchard clay with a moisture content of 16.8% and a measured angle of repose of 35.55°, parameter calibration was performed. The contact model “Hertz-Mindlin with Johnson-Kendall-Roberts” was selected in EDEM. Using Design Expert, a regression model variance analysis was applied to the discrete element model parameters, leading to the determination of the optimal values for significant soil model parameters. The soil JKR surface energy is 5.85 J·m−2, with a soil–soil restitution coefficient of 0.65 and a soil–steel static friction coefficient of 0.5. Subsequently, discrete element simulation experiments on the drilling apparatus were conducted in EDEM, considering various rotation speeds and feed rates. The simulation analysis indicates that the torque consistently increases with higher rotation speeds, with a maximum relative error of 7%. The torque initially rises from zero to a maximum value, then gradually decreases to a low value, followed by a rapid increase to a higher value, and finally drops back down. This cycle repeats in the observed pattern. The total force experienced reaches its minimum average value of 200 N at a feed rate of 0.05 m/s. Simulation test results indicate that, among the three forces acting on the auger (vertical resistance, horizontal resistance, and lateral resistance), vertical resistance is the primary factor contributing to power consumption. As the rotation speed increases, the maximum value of vertical resistance continues to rise, while horizontal resistance and lateral resistance exhibit a declining trend. As the feed rate increases, the maximum values of resistance in all three directions also increase. When the feed rate exceeds 0.05 m/s, the maximum lateral resistance experiences a sharp increase. Through comprehensive analysis, the optimal operational parameters for borehole fertilization are determined to be a rotation speed of 100 r·min−1 and a feed rate of 0.05 m/s. The aim of this study is to reduce the energy consumption of borehole fertilization operations, minimize carbon emissions, and promote the sustainable development of orchard production.

Experimental study of wellbore strengthening on pressure-bearing capacity

Based on the method of hydraulic fracturing, the simulation experimental device and method of wellbore strengthening pressure bearing capacity were established, and the optimization experimental study of wellbore strengthening process parameters was carried out. A new mechanism of wellbore strengthening based on the synergistic balance of fracturing damage and pressure-bearing capacity was proposed. The results show that the wellbore strengthening effect of intermittent squeezing is more significant than that of direct squeezing. Among them, the effect of constant pressure intermittent squeezing to improve the formation pressure bearing capacity is the best, followed by depressurization squeezing. With the increase of intermittent squeezing pressure, the pressure bearing capacity gradually decreases, and the optimal squeezing pressure is 1/4 of the fracturing pressure. Within the controllable range of rock strength and damage caused by hydraulic fracturing, the plugging efficiency of wellbore strengthening materials can be improved by appropriately increasing the times of squeezing. The optimal time of squeezing is about 5. Under the indoor simulation conditions, confining pressure has no significant effect on wellbore strengthening, which may reduce the plugging efficiency of wellbore strengthening materials.

PROPERTIES OF A SECONDARY DISCHARGE PLASMA SUPPORTED BY A ROTATING GLIDING DISCHARGE

In this work, the results of an experimental study of plasma parameters of a secondary discharge at atmospheric pressure, sustained by a low-power (~ 100 W) rotating gliding discharge in an air stream under conditions of a significant excess of the plasma channel length of the secondary discharge over the length of the self-sustained discharge channel in the range of 1...100, are presented. Plasma parameter determination was carried out using emission spectroscopy of the plasma with the SpecAir program. The assessment of the electric field intensity in the secondary discharge plasma was based on the dependencies between the discharge voltage drop and the length of the discharge current channel.

Experimental Study of Multiple Physical Parameters Monitoring during Uniaxial Loading Process of Sandstone

Aiming at the damage evolution and energy release characteristics of sandstone in failure process, uniaxial and cyclic loading experiments were conducted with the average temperature, infrared temperature field, acoustic emission (AE), and displacement field being monitored simultaneously. The results show that in the low stress stage, the initial pores and fissures are compressed and the thermoelastic effect is insignificant. At the same time, the AE events are active, but most of the events are released with low energy. Then, the surface of the specimen shows stratified displacement phenomenon in the vertical direction. In the following stage, the thermoelastic effect is significant, and the average temperature of specimens shows a linear correlation with stress, whereas the AE is relatively inactive, and vertical surface deformation shows further homogenization and saliency. Because of the top and bottom constraints, the horizontal displacement field shows axis symmetrical distribution of double half-ellipse like a drum. During the yielding phase and the rupture moment, the average temperature rises obviously because of the heat from the friction of the rupture surface, and the temperature field also appears the phenomenon of differentiation; in the meantime, a large amount of AE events occur and the proportion of high energy events increases; further, the deformation field is significantly gathered near the ruptured position. Finally, the time sequence of the multiple physical parameters (AE parameters, average temperature, temperature fields, horizontal and vertical displacement fields) is summarized, which can be a reference for the stress state and failure analysis.

Experimental Study of Variation Sediments and Effective Hydraulic Parameters on Scour Downstream of Stepped Spillway

Experimental Study of Variation Sediments and Effective Hydraulic Parameters on Scour Downstream of Stepped Spillway

Experimental study of explosion parameters of hybrid mixture caused by thermal runaway of lithium-ion battery

The explosion characteristics of the runaway battery vented gas (BVG) was studied using an 8 L column type device. The effects of ambient temperature, turbulence condition, and graphite dusts-ejected along with the BVG on the explosion process-were investigated. At 25 ℃, the explosion limits of pure BVG, the maximum explosion pressure (Pmax), and the maximum rate of explosion pressure rise (dP/dt)max is 10.8–45.8% by volume, 0.62 MPa, and 37.6 MPa/s, respectively. At 80 ℃, the three parameters changed to 10.4%− 46.5%, 0.49 MPa and 35.5 MPa/s. Moreover, these three parameters changed to 10.2–47.5%, 0.45 MPa and 33.3 MPa/s at 120 ℃. The increase in temperature reduced Pmax of BVG. While turbulence had little effect on the explosion pressure of BVG, it has significantly affected the dP/dt value. Adding graphite dusts helps BVG get to Pmax at a much lower volume concentration. As temperature increased, this effect became greater. Also, the graphite dusts can reduce the time of BVG to attain the Pmax value after igniting – the maximum reduction is from 325 ms to 158 ms. As ambient temperature increased, the combustible gas molecules were reduced, resulting in a lower Pmax value. The heat released from the BVG explosion drives the graphite involving dust explosion when oxygen is excessive. The above findings can provide a reference for the prevention of environmental explosions caused by the thermal runaway of lithium-ion batteries in process industry.

Prediction of water quality under the impacts of fine dust and sand storm events using an experimental model and multivariate regression analysis

Many regions of the world, especially arid and semiarid areas, occasionally experience fine dust and sandstorms, known environmental problems that make normal life difficult. Since the intrusion of large amounts of dust into treatment plants may significantly change the water quality indices, the main goal of this study was to estimate these indices during the events, which can help decision-makers to improve water quality. To achieve relationships using nonlinear multivariate regression analysis, a long-term (three years: April 2017–February 2020) experimental study of water quality parameters including total dissolved solids (TDS), hydrogen content (pH), electrical conductivity (EC), chlorine (Cl), total hardness, sodium (Na), and magnesium (Mg) for water samples from wastewater treatment plants in Sistan region (Iran) was conducted where is one of the most popular regions in the world with high amount of annual fine dust level. Analysis of ANOVA showed that of all the independent parameters considered in this study, water quality parameters strongly correlated with monthly mean sand and dust storm index (SDSI), wind speed, temperature, and the number of monthly windy days. For the regression analysis, 25 months of data were used for the simulation process and 10 months for validation. The final results showed that the relationships obtained from the nonlinear multivariate regression analysis could predict the water quality indices very well (with R2 more than 0.75) except for Mg with R2 equal to 0.55. In addition, the maximum mean relative error belongs to Mg (10.8%) and then Na (9.9%) whereas the minimum mean relative error belongs to pH (2.6%) and then EC (2.9%).

Optimization and Experimental Study of Structural Parameters for a Low-Damage Packing Device on an Apple Harvesting Platform

To address the issues of low efficiency and high damage rates during apple harvesting and packing, a parameter optimization experiment was conducted on a low-damage packing device for an apple harvesting platform based on Adams 2019 software. The aim was to reduce the mechanical damage to apples during the packing process. Firstly, kinematics and energetics analyses of the apple packing process were performed, and a mathematical model for damage energy was established to identify the main factors and their ranges that influence the mechanical damage to apples. Secondly, using the fruit damage rate and packing efficiency as the evaluation criteria, a second-order orthogonal rotating regression experiment was conducted with the inclination angle of the fruit conveying tube, the inner wall radius of the fruit conveying tube, and the length of the fruit conveying tube as the experimental factors. Regression mathematical models were established to assess the relationship between the evaluation criteria and the experimental factors. Finally, the impact of each experimental factor on the evaluation criteria was analyzed to determine the optimal structural parameters for the low-damage packing device of the apple harvesting platform, and validation experiments were conducted. The results showed that when the inclination angle of the fruit conveying tube was 47°, the inner wall radius of the fruit conveying tube was 84 mm and the length of the fruit conveying tube was 0.12 m, the average fruit damage rate was minimized at 7.2%, and the average packing efficiency was maximized at 1925 kg/h. These results meet the requirements for apple harvesting operations, and the research findings can serve as a reference for the structural design and packing operation parameter optimization of apple harvesting platforms.

Study of natural convection heat transfer for a cylindrical and semicylindrical heat transfer system geometry

The paper presents the experimental and numerical study of the heat transfer parameters for the heated tube bank and arc-shaped plate made up of four tubes and four arc protrusions arranged one above the other. To evaluate the local heat transfer coefficients, the holographic interferometry is used as the experimental method, while the numerical simulations are performed by the Ansys Fluent software. The tube bank supplemented by the fin of different thickness and the double arc-shaped plate is further considered to improve the heat transfer parameters and the numerical results are compared with the basic arrangements. Considering the natural convection, the Rayleigh numbers are specified in the range of 16,460 to 46,340. It is observed that the tube bank achieves a higher average Nusselt number in the range of 37%–82% compared with the other arrangements depending on the Rayleigh number. The tube bank with fins does not increase the heat transfer parameters; however, there is an increase in average heat flux compared to the tube bank without fins. The double arc-shaped plate arrangement slightly increases the heat transfer and markedly increases the average heat flux compared to the single one. The highest average heat flux is achieved for the double arc-shaped plate and tube bank with fins in the range of 27.430 Wm-2 to 126.139 Wm-2.

Research of Electromagnetic Parameters of the Radio-Frequency Micromechanical Switch Designed for Operation in 5G Transceiver Systems

This article presents the results of an experimental study of the electromagnetic parameters (scattering parameters) of a manufactured experimental sample of a capacitive single-pole single-throw radio-frequency micromechanical switch with an electrostatic activation mechanism designed to operate in the transceiver radio-modules of 5G mobile networks in the frequency range NR FR1, namely at a central resonant electrical frequency of 3,6 GHz. The effective operating frequency range of the developed and manufactured experimental sample of a radio-frequency micromechanical switch is the S-frequency range. The basis for the development of the presented experimental sample is the developed methodology for designing capacitive radio-frequency micromechanical switches with an electrostatic activation mechanism.

Experimental study of acoustic emission parameters during cyclic testing of metal products of additive manufacturing

Experimental study of acoustic emission parameters during cyclic testing of metal products of additive manufacturing