Computer Simulation Program Research Articles

The Effect of Fluorine and Hydrogen Concentrations on the Chain Reaction of HF Chemical Laser

A numerical investigation has been performed to examine the effect of fluorine concentration on the chain reaction mechanisms and parameters of hydrogen fluoride (HF) chemical laser. The practical difficulties associated with this type of lasers impose that an alternative route might be quite useful. Thus, particular attention was paid to develop a computer program to investigate various processes. The results of this computer simulation program proved their credibility when compared with the little published data. This computer program is called Reaction Rate Simulation Model (RRSM). An entirely new approach to emulate the reaction mechanisms has been followed. The effectiveness of reaction rates in the processes of HF laser production has been investigated. This simulation program dealt with the percentages of the forward and reverse reactions, when a large number of reactions have been considered. In addition a large number of species have been taken into account in these reactions. From the computer program (RRSM), some valuable results could be predicted with regard to the hydrogen fluoride chemical laser.

Performance Evaluation of Solar Photovoltaic Thermal Air Collector Based on Energy and Exergy Analysis

This work presents a comprehensive parametric study of thermal and electrical performance of four different designs of photovoltaic/ thermal air heaters (PV/T) based on energy and exergy analysis. The results are compared to that from the conventional design of flat duct PV/T. The main goal of these designs is to enhance the heat transfer inside the air duct and consequently to increase the system's electrical power output. A computer simulation program has been developed in order to calculate the electrical and thermal PV/T collector parameters. The results indicate that an increase of 52, 52.4, and 68.25 % in the total system efficiency has been achieved from the corrugated duct, double pass design and finned duct respectively. Furthermore, at a low mass flow rates the electrical efficiency has also been improved for the three types by 9.8, 14.6 and 12.6 % respectively compared to that of flat duct design. The temperature of the PV arrays has a major effect on the exergy efficiency and removing heat from the PV module keeps the net power output at satisfactory level.

Crystallographic and electrochemical corrosion resistance analyses of cataphoretically co-deposited spinel Co>0.5Mn0.1-0.3O0.1-0.4@rGO composites over α-Fe(110) as current collector for supercapatteries

Binder free spinel Co>0.5Mn0.1-0.3O0.1-0.4@rGO composite electrode films were fabricated via galvanostatic electrochemical deposition technique over α-Fe(110) as current collector for hybrid supercapattery. Self-designed, n-MOSFET embedded ATMega328P microcontroller assisted modules were deployed to record the chronopotentiometric as well as galvanostatic charging-discharging analysis for specific capacitance (Cs) measurements. Partial, exchange as well as limiting current densities(iL) and cathodic current efficiency were estimated. Electrochemical signature was analyzed from cyclic voltammetry data. Morphology and chemical nature of the composites were scrutinized with scanning electron microscopy, X-ray photoelectron, FT-IR and Raman spectra. Indigenously designed computer simulation programs coded in Python were used to optimize the deposition parameters and to analyze the crystalline structure from XRD data. The unit cell length for the FCC crystal with an octahedral geometry was ∼ 4.28 Å. An in-depth analysis of potentiodynamic polarization as well as electrochemical impedance spectral data were carried out to scrutinize the corrosion resistance and capacitance characteristics of the composites in KOH. From the Tafel constants, Ecorr, Icorr, Ru, RCT and ZW data, it was accentuated that rGO incorporated composite films offer enhanced corrosion protection for Fe(110) substrates than their individual counterparts along with augmented specific capacitance. Estimated Cs was about 1166 F.g−1 at a scan-rate of 10 mV.s−1. Impact of time-constant (τ) and current density over Cs was analyzed via GCD technique and was about 1458.73 F.g−1 at 2 τ and at 0.5 A.g−1. And the corresponding specific energy and power density were about 183.23 W.h.kg−1 and 237.75 W.kg−1 respectively. These composite electrode films impregnated with rGO not only improved the specific capacitance but also imparts the sacrificial corrosion resistance over the α-Fe(110) as current collector in presence of OH−as electrolyte and can serve as a sustainable electrode material for supercapatteries.

Analysis of the Vapor Compression Refrigeration Cycle Measures with and without Using a Heat Exchanger for Alternative Refrigerants

One of the most commonly refrigeration systems is the vapor compression refrigeration system. Since energy saving and environmental friendliness remain a challenge, researchers are working hard to find an effective solution to improve the performance of vapor compression refrigeration systems while committing to environmental standards. The main goal of this paper is to identify the best and closest alternative refrigerant to R22 among the alternative cooling fluids taken into consideration in terms of thermodynamic and mechanical properties, environmental protection, and safety of handling. This work presents an analysis and comparison of the various performance measures for a vapor compression refrigeration cycle operating without using and using a heat exchanger for environmentally friendly alternative refrigerants, namely R410A, R407A, R407C, R438, RS-44b, and R417A, and compares them with the refrigerant R22, which has direct environmental impacts on the ozone layer (ODP) and global warming (GWP). The computer simulation program Chemours Refrigerant Expert 1 was used to conduct the analyses. The performance parameters analyzed are coefficient of performance, compressor work, cooling capacity, temperature of condensation, intake and exhaust pressure, volumetric capacity, theoretical displacement, intake, exhaust, condensation and evaporation temperature without and with a heat exchanger, and super heating temperature with a heat exchanger. It was concluded from this study that the best alternative to R22 refrigerant among the alternative refrigerants taken into consideration in the study is the RS-44b refrigerant in terms of all performance measures and environmentally friendly. Keywords: Refrigerant; Vapor compression; Performance measures; Evaporation; Heat exchanger.

Effect of the Geometric Shapes of Elevated Tanks on their Dynamic Response

This study examines the impacts of geometric shapes of elevated tanks owing to the seismic loading action. Four typical tank shapes have been studied, namely: intze tank with a shaft, pure conical tank with a frame, combined conical tank, and cylindrical tank with a frame through a single degree of freedom, two degrees of freedom, and three dimensional finite element method, based on the full and empty condition using computer simulation program LUSAS FEA through added mass approach for accounting fluid-structure interaction. The results revealed that the intze shape is the most suitable shape to be analyzed based on mechanical approaches. While the impossibility of applying these approaches to conical tanks.

Solid phase microextraction device coupled with miniature mass spectrometry and mathematical model of its ion chronogram

Modern solid phase microextraction (SPME) device linked with mass spectrometry (SPME-MS) has evolved from producing ion chronogram as flat noisy signal to as unimodal-like signal. We designed a SPME device, which is closer in morphology to LC column, linked it with a miniature mass spectrometer (SPME-Mini MS), and proposed a mathematical model that elution of compound from the SPME device is equivalent to overlay of elution of the compound from the infinite LC columns with the lengths between 0 and the length of the device and it can generate an ion chronogram as right-skew unimodal signal. Rhodamine B as analyte was used for experimental verification and its unimodal signal was used to fit the parameters of a computer simulation program based on the model. The experimental results and simulations empirically cross-confirmed that SPME-Mini MS can generate ion chronogram as clean right-skew unimodal signal. Furthermore, the SPME-Mini MS system was used for quantitative analysis of psychotropic drugs (i.e. risperidone and aripiprazole) in artificial urine. The results preliminarily demonstrated that the system can utilize area under unimodal signal for quantitative analysis and has potential to be applied for on-site, fast and accurate quantification of drugs and other compounds.

Towards Achieving Sustainable Environmental Efficiency: Rationalizing Energy used in Educational Buildings of University Campus

The research deals with a practical and analytical study comparing the use of the computer program for digital simulation, Design Builder, to calculate the amount of energy consumption in buildings, as the aim of the research is to conclude the most influential architectural elements in reducing energy consumption in the typical building of Al-Azhar College of Engineering for Girls (CEG). This is done by calculating the amount of energy consumption of the college building with its existing specifications while making architectural modifications to the building to conclude which elements have an impact on reducing energy consumption under the influence of the climatic conditions of the city of Cairo. These architectural elements include treating the glass surfaces and curtain walls in the building and increasing the operating temperature of the air conditioners to cool the building, as it is clear from the simulation results that the greatest reduction in the building’s cooling load is by 40%. The research concludes with recommendations that contribute to energy rationalization in educational buildings on campus, thus achieving efficiency in the internal and external environment.

Research on Sports Training Model Based on Training 3D Modeling Technology

The Visual C++ development environment is used, combined with computer simulation software programming and programs to realize the virtual reality of sports training, and realize the comprehensive attack drill of sports training in various sports training environments. Finally, a simulation study is carried out on the 3D model of basketball movement. Research has shown that simulation techniques are able to achieve better training scenarios than reality. It can be used for full attack practice in sports. This system provides a rich set of teaching methods for athletes' comprehensive attack, which helps athletes to have a correct understanding of various tactical systems in the game. It can promote the scientific development of sports teaching.

Does information disclosure alleviate overcrowding? An empirical study based on large-scale COVID-19 nucleic acid test

Nucleic acid testing is a critical means of combating COVID-19. However, the overcrowding caused by large-scale nucleic acid testing increases the risk of virus infection and challenges the existing health supply chain. Aiming at alleviating overcrowding, this paper studies the determinants of people’s choice of testing sites. The results show that physical distance and decision information exert positive influences, whereas the impact of urgency is not significant. The results of a specially designed computer simulation program verify the empirical study. It was also found that information disclosure does not affect the overall completion rate of the nucleic acid testing and the average time taken to complete the testing. However, it aggravates overcrowding in queues. The findings overturn the previous view that information disclosure improves social efficiency. This paper acts as a reference for governments dealing with overcrowding during large-scale social mobilization.

Calculation of the mean emission power in a mobile network cell as a function of users’ density distribution

In this paper we consider two random variables in a cell in the network of mobile users. The first random variable (RV) is the distance of active mobile user from a base station. The second RV is emission power for the random active user if the control of emission power exists. RV emission power is dependent RV of the first RV. That’s why the calculations of mean values for these RVs differ one from the other. The first RV depends only on the users’ density area distribution. The second RV depends on the signal attenuation value in the considered environment. It is proved that, in real conditions, emission power to a user at the mean value of distance from a base station is always lower than mean value of emission power to a user. The difference between these two power values increases as the signal attenuation coefficient increases. These two values are calculated for three characteristic user density distributions in a cell. The results are verified by original computer simulation programs.

Landscape evolution modeling of the normal-fault scarps (Baikal rift system): new experience

The paper considers a new method for determining the quantitative parameters of the relief-forming processes characteristic of the mountainous framing of the basins of the Baikal Rift System (BRS), based on the use of a computer program for numerical simulation of the evolution of the relief CHILD. Particular emphasis was placed on the calculation of approximate values of the rate of tectonic uplift of the near-fault block structures of the Baikal rift. The novelty of the study lies in the adaptation of the CHILD program for solving fault tectonics problems, as well as in the development of a morphotectonic analysis algorithm aimed at searching for specific geomorphological objects that can be considered as uplift indicators. As a result of a series of experiments performed using radioisotope data, three-dimensional models were obtained that simulate the development of near-fault slopes at the Late Cenozoic stage of the development of the BRS, and the probable rates of vertical movements along the faults of the region were determined. It was found that the average Late Cenozoic uplift rates vary within a narrow range of 0,3–0,5 mm/yr, with higher values associated with the northern and northwestern flanks.

Stakeholder Model for Standard Operating Procedure of Radiation Safety Practice in Radiopharmaceutical Therapy

Using Xofigo procedure as an example of radiopharmaceutical therapy, to provide a quantitative analysis methodology for standard operating procedure development with binary stakeholder model. A Xofigo procedure was selected for this study. After nurse places the intravenous (IV) pole and start delivery of the saline liquid into the patients for required temporal period, calibrated Xofigo syringe will be transported into the treatment room by medical physicist and authorized radiation oncologist starts injecting the Xofigo liquid into the patient through the 3-way stopcock. During this process, the status of liquid path is from the syringe with Xofigo liquid to patient, and the saline liquid tube is shutoff. After about 1 minutes of injection, which most of the Xofigo radioactive liquid is injected into patient side, the 3-way stopcock will shut off the connection between the patient and syringe. The saline liquid then is abstracted into in the syringe from the saline bag hung on the IV pole, the liquid amount will be used for diluting the residual Xofigo liquid inside the syringe. Then the 3-way stopcock switch is switched off the connection between the saline bag and the syringe, and syringe is connected to the patient side again, then the saline liquid inside the syringe is injected into patient, and this process dilutes the residual Xofigo radioactive liquid at the inside surface of the syringe and the path to the patient. This dilution process could repeat a few times, depends on the estimation of residual amount. Then the syringe will be unscrewed from the 3-way stopcock by opening the path from the saline bag to the patient. At this moment, the saline is switched off from outside by cutting the tube with a scissor or unscrewed from the 3-way stopcock. A binary stakeholder quantitative model was used to evaluate the last step with a computational simulation program the tube cut-off process. Based on the numerical results from the simulation program, at the best situation, if the residual isotope liquid had been diluted completely, the radiative dose to both procedures would not be different, and the only difference is the tool used and workload dispatch to both medical physicist and radiation oncologist. And at the worst scenario, there were some radioactive residuals had gone into the IV-saline tube, then the radioactive contamination could be in the scissor, both side of cut off tube, and potential contacting point will increase to two stakeholders, one more tool(scissor), which could be treated as a stakeholder. The optimization principle could be simplified as to decrease the contacting point and contacting stakeholders by a computational simulation of a stakeholder model for a Xofigo radiopharmaceutical procedure. The analysis methodology could expand to all the steps in radiopharmaceutical therapy in developing a standard operating procedure and other complex radiation safety practice simulation system.

Numerical Study of a Three-Bed Adsorption Chiller Employing an Advanced Mass Recovery Process

The performance improvement of a three-bed (equal bed) adsorption chiller employing an advanced mass recovery process has been numerically studied in this paper. The mass recovery scheme is used to improve the cooling effect and a CFC-free-based sorption chiller driven by the low-grade waste heat or any renewable energy source can be developed for the next generation of refrigeration. Silica gel/water is taken as adsorbent/adsorbate pair for the present chiller. The three-bed adsorption chiller comprises with three adsorber/desorber heat exchanger, one evaporator and one condenser. In the present numerical solution, the heat source temperature variation is taken from 500C to 900C along with coolant inlet temperature at 300C and the chilled water inlet temperature at 140C. In the new strategy, if any one bed (3rd bed) is connect with the evaporator during pre-heating or pre-cooling time then it will give better performance than that of existing system. In this strategy, mass recovery process also occurs in all bed. A cycle simulation computer program is constructed to analyze the influence of operating conditions (hot and cooling water temperature) on COP (coefficient of performance), and CC (cooling capacity).

Physical Therapy May Not Be Successful for Patients With Cam-Type Femoroacetabular Impingement Syndrome and May Result in Insufficient Hip Range of Motion When Femoral Anteversion Is Less Than 16° and α-Angle Is Greater Than 65°

To identify factors associated with insufficient range of motion (ROM) improvement after the posterior pelvic tilt change in cam-type femoroacetabular impingement syndrome. Preoperative computed tomography images from 71 consecutive patients with femoroacetabular impingement syndrome treated with arthroscopic cam resection were evaluated. Using a dynamic computer simulation program, 3-dimensional models with a 10° posterior pelvic tilt from the supine functional pelvic plane (baseline) were created by computed tomography models. Patients were divided into 2 groups: those who experienced >10° (effective group) and ≤10° (ineffective group) improvements in internal rotation at 90° flexion after a 10° posterior pelvic tilt. Demographic characteristics; preoperative range of internal rotation at 90° flexion; and radiographic parameters, including Tönnis grade, lateral center-edge angle, acetabular roof obliquity angle, central acetabular anteversion, cranial acetabular anteversion, femoral anteversion, and α angle, were compared in the 2 groups. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with insufficient ROM improvement following a 10° posterior pelvic tilt. The 71 patients included 58 men and 13 women, of mean age 41.4 ± 14.6 years. Posterior pelvic tilt was effective in 13 hips and ineffective in 58. Univariate analysis showed that preoperative range of internal rotation at 90°flexion, femoral anteversion, and α angle differed significantly in the 2 groups. Multivariable analysis showed that femoral anteversion <16° (odds ratio 7.4; 95% confidence interval 1.6-35; P= .012) and α angle >65° (odds ratio 6.7; 95% confidence interval 1.2-37; P= .027) were significant factors associated with insufficient ROM improvement after posterior pelvic tilt. Physical therapy may not be successful for patients with cam-type femoroacetabular impingement syndrome and may result in insufficient hip ROM when femoral anteversion is less than 16° and α-angle is greater than 65°. Patients with a prominent cam-type deformity and lower anterior femoral anteversion are at high risk of clinical failure following improvement in pelvic mobility by conservative treatment alone and are likely to benefit from surgery for cam deformity.

Gender difference in secondary school students’ retention in algebra: A computer simulation approach

This research examined how well learners retained algebra concepts after using a computer simulation program. Two research questions and two hypotheses guided the study. A quasi-experimental design was employed. The population consisted of 2,152 junior secondary school two (JSS 2) students from the Udenu Local Government Area in Enugu State. 115 students from two co-educational schools were the study’s sample. Each school had two streams of JSS 2 classrooms, with the experimental and control groups being randomly assigned. The algebra achievement test, which has a reliability score of 0.88, was used to gather the data for this study. The statistical package for social sciences software was used to analyze the collected data. According to the data, students taught algebra using computer simulation had considerably higher average retention scores compared to learners taught utilizing the traditional method. The data revealed furthermore that, a significant gender difference occurred in the mean retention scores of students taught algebra concepts utilizing computer simulation.

Numerical Investigation of Diffraction Patterns of Small Size Apertures Using Light Sources From Xuv to The Visible Region: Simulation for The Small Size Structures

In the present work, a computer simulation program generates Fresnel diffraction patterns from small-size apertures using illumination wavelengths from extreme ultraviolet (XUV) to the visible region suggesting that it can be used to model a wide range of experimental setups. By being able to simulate diffraction patterns for such a broad range of wavelengths, the program can be used to investigate the effects of varying wavelengths and aperture size on the resulting pattern. By using a computer simulation program that can generate Fresnel diffraction patterns across a wide range of wavelengths, one can explore how different wavelengths of light interact with various aperture sizes. This allows one to investigate the effects of changing these parameters on the resulting diffraction pattern. The computer simulation program generating Fresnel diffraction patterns from square apertures by using the illumination wavelength sources from XUV to the visible region has been studied. Changing the aperture-screen distance, the illumination wavelength, and the aperture size provides a clear transition of diffraction patterns from the Fresnel to the Fraunhofer region. The diffraction patterns obtained by the Fresnel integral method have been compared with that simulated by the Fraunhofer calculation. There is a good agreement between the results. The structural similarity index (SSI) exhibits that comparing the diffraction images produced with both approaches agree.

Техникалық қызмет көрсету көлемін оңтайландыру негізінде моделі у35.615 гидромеханикалық беріліс қорабы сенімділігін арттыру

Calculation of the costs of creating operational reliability when troubleshooting gearbox in the hydromechanical gearbox and eliminating the regularities of the restoration processes of its operation took into account the nature of the ongoing repair work. Calculation of the main deficit function is carried out in relation to the processes of restoring computer operability, including non-stationary processes in general, using a computer simulation program developed by a computer.

Development of a method for online control of plastic deformations of a tank wall and assessment of its residual life

A method of operational control of the residual resource of the tank is proposed. As a tool, the measurement of deformations of the tank wall, the assessment of plastic deformations are used. To determine the deformation, it is proposed to use a light guide installed on the wall, with the help of which the change in the curvature of the wall is measured. A device prototype containing a light guide and the necessary electronics has been developed, and the dependence of the device readings on the curvature of the light guide has been experimentally determined. The simulation of the tank in the computer simulation program was carried out in order to compare the integral of the relative deformation over the height of the tank with the readings of the device. An algorithm for processing measurements of device readings and estimating the residual life of the tank is proposed.

The Phasor Diagram of a Superconducting Synchronous Electrical Machine

This paper describes a universal method proposed by the author for the evaluative analytical calculation of the main parameters of synchronous electrical machines, including superconducting ones. Traditional methods for analytical calculation of parameters to build a phasor diagram of electrical machines require a calculation of all dimensions of the active zone, tooth-slot zone and frontal parts of armature windings. All sizes and local states of magnetic circuit saturation are necessary for the calculation of magnetic conductivities. Traditional analytical methods use, among other things, empirical formulas and non-physical coefficients and allow one to calculate only standard machines with classic tooth-slot zones and armature winding types. As a result of drawing a phasor diagram using traditional methods, the angle between the electromotive force and voltage is calculated, which is the machine’s internal parameter and has no major significance for users. The application of modern computer programs for simulation requires a preliminary analytical calculation in order to obtain all dimensions of the three-dimensional model. FEM simulation programs are expensive, require expensive high-performance computers and highly paid skilled personnel. Fast analytical techniques are also required to assess the correctness of the obtained automatic computer simulation results. The proposed analytical method makes it possible to quickly obtain all the main parameters of a newly designed machine (including superconducting ones and those of non-traditional design) without a detailed calculation of the dimensions of the tooth-slot zone and armature end-windings. The characteristic values of load angles are set according to the results of simple calculations, and the desired values, obtained via plotting, represent the inductive resistances of armature winding and inductive voltage drop across it. Results of practical significance, calculated from the voltage diagram, are as follows: the inductor’s magnetomotive force necessary to maintain the nominal load voltage value, regardless of the magnitude (including double overload) and type of the connected load, or the main dimensions of the active zone.

Моделирование работы диода и оценка параметров его работы

The article discusses the simulation of the operation of a diode based on the compiled electrical circuit, and also considers the analysis of the operation of the dido under various operating conditions using the AnyDynamics 8 computer simulation program. Various approaches to the concept of modeling, model, and mathematical model are considered. The classification of models of semiconductor devices, current-voltage characteristic (CVC) and device operation scheme are evaluated. The physical properties of the diode are considered, then a transition is made to the analysis of the operation of the diode in a physical model, and on its basis a mathematical model of the diode is built, since the model works with small changes in current and voltage, then the transition is made to a low-signal model and a system of differential equations, behavior of an ideal diode. Classes of elementary elements are being developed, from which it is possible to build an electronic circuit, diode, resistor, capacitor, coil. A circuit is determined with the help of which it is possible to simulate the operation of a circuit with a connected ideal diode. The result of the work of the electrical circuit in the program AnyDynamics 8 was the creation o behavior of an ideal diode. Analysis of the obtained graphs in the future will allow you to perform modeling and analysis of the operation of an ideal diode.