Computer Simulation Program Research Articles

Mechanical discrete simulator of the electro-mechanical lift with n:1 roping

The design process of new products in lift engineering is a difficult task due to, mainly, the complexity and slenderness of the lift system, demanding a predictive tool for the lift mechanics. A mechanical ad-hoc discrete simulator, as an alternative to ‘general purpose’ mechanical simulators is proposed. Firstly, the synthesis and experimentation process that has led to establish a suitable model capable of simulating accurately the response of the electromechanical lift is discussed. Then, the equations of motion are derived. The model comprises a discrete system of 5 vertically displaceable masses (car, counterweight, car frame, passengers/loads and lift drive), an inertial mass of the assembly tension pulley-rotor shaft which can rotate about the machine axis and 6 mechanical connectors with 1:1 suspension layout. The model is extended to any n:1 roping lift by setting 6 equivalent mechanical components (suspension systems for car and counterweight, lift drive silent blocks, tension pulley-lift drive stator and passengers/load equivalent spring-damper) by inductive inference from 1:1 and generalized 2:1 roping system. The application to simulate real elevator systems is proposed by numeric time integration of the governing equations using the Kutta-Meden algorithm and implemented in a computer program for ad-hoc elevator simulation called ElevaCAD.

Properties of superdeformed bands in A ∼ 190 region within the framework of three parameters nuclear softness model

The three parameters nuclear softness model (NS3) have been applied to eleven superdeformed (SD) bands of A ≈190 mass region namely: 191Hg(SD2,SD3), 192Hg(SD1), 194Hg(SD1,SD2), 193Tl(SD1,SD2), 194Tl(SD1,SD3, SD5) and 194Pb(SD1). The level spins and the model parameters are determined by fitting the electric quadrupole transition energies Eγ with the experimental ones, by using a computer simulated search program. Rotational frequencies ħω, kinematic J(1) and dynamic J(2)moments of inertia and the quadrupole deformation parameter β2 have been calculated. In all cases of our selected SD bands the results obtained are in good agreement with experimental ones. J(2) reveal a steady increase with ħω, this can be attributed to the successive alignment of πi13/2 (N = 6) and υj15/2 (N = 7) intruder orbitals in the presence of dynamical pairing correlations. The presence of ΔI = 2 staggering in the two SD bands 1,2 of 194Hg and in the three SD bands 1,3,5 of 194Tl have been investigated by calculating the staggering parameter which represent the fourth order derivative of the gamma-ray transition energies. Also the ΔI = 1 staggering in SD bands of odd nuclei has been investigated in the signature partner pairs 191Hg (SD2, SD3) and 193Tl (SD1, SD2). The yrast SD bands in the isotones 194Pb and 192Hg have almost identical transition energies which implies that their J(2) are also identical. This indicates that either the two occupied 5/2+[642] protons have a very weak influence on Eγ and J(2).

MODELS OF HOURLY DRY BULB TEMPERATURE AND RELATIVE HUMIDITY OF KEY SELECTED AREAS IN NIGERIA FOR ENGINEERING APPLICATIONS

Hourly meteorological data of both dry bulb temperature and relative humidity for 18 locations in Nigeria for the period 1995 to 2009 were analysed to obtain the mean monthly average and monthly hourly average of each of the two meteorological variables for each month for each location. The difference between the maximum and minimum values of the monthly hourly averages of each variable for each month were also computed and taken as the range of that variable for each location. The monthly hourly averages of each variable for each month and for each location were standardized by subtracting the mean monthly average from it and dividing it by the computed range and plotted against time. Twelve curves for the months of the year were obtained for each of the eighteen locations making a total of 216 curves for each meteorological variable. The average of the 216 curves was used to develop Fourier series for each variable. Mean Forecast Error (MFE), Mean Absolute Deviation (MAD) and Mean Absolute Percentage Error (MAPE) were used to compare results of the models with results from the meteorological data. The agreements between them were very good. The values of the mean monthly averages and the ranges for dry bulb temperature and relative humidity were presented in Tables so that these input values that need to be fed into the models are readily available. Since the eighteen locations are well spread out over Nigeria, it is appropriate to use these models as inputs in computer programs for simulation of refrigerator, air conditioning systems and internal combustion engines operating anywhere in Nigeria. http://dx.doi.org/10.4314/njt.v35i2.17

MENYIASATI FASILITAS LABORATORIUM CNC BAGI SMK YANG BERKEKURANGAN FINANSIAL

Vocational secondary education (SMK) focused on how to yield a graduate with a high skill level so ready to use as an operator in the world of work (Samadhi, 2014). Therefore kebaradaan laboratory is one of facilities must-have. However, reality shows that there are many SMKs that do not have a CNC laboratory. Lack of adequate funds become classics reasons. This is understandable, because to have a CNC machine worth taking that simple though they should provide funds at least Rp. 350 million, CNC simulator is a highly qualified computer simulation program of CNC machining. From the financial side, this simulator is much very cheap price but in terms of its ability to go far beyond the minimum requirements most of CNC laboratories in SMK existing present. The simulator looks so lively and interesting so that users feel really were in front of actual CNC machine. Because of the strengths of that, the hypothesis could be built is CNC simulators can be used as a medium of learning in the laboratory for the SMK that because of limited funds they dont have a CNC laboratory yet. The research was designed to prove the hypothesis. By using a Likert scale analysis of qualitative data and the data pairs μ test for quantitative data, ultimately it can be seen that the respondents (students and teachers) feel very satisfied (93.33% Likert scale) when using the CNC simulator and because it was an average capability in the field of CNC programming be increased from 73.6 to 95.7 for students and from 98.9 to 87.3 for teachers. From financial aspects the CNC simulator is able to lower the cost of laboratory operations from Rp. 755,000 per month to stay Rp. 175,000 per month. And finally it can be concluded that the simulator can be used to circumvent CNC laboratory in SMK that don’t have much money.Kata kunci: laboratorium CNC, SMK berkekurangan finansial, simulator CNC

Performance evaluation of flash tank-absorption cooling cycle using two ejectors

Combining the ejector-flash tank with the single stage absorption cycle has shown potential improvement in the COP. However, the cycle is still subject for further enhancement. Addition of two ejectors in the cycle to work under low-pressure of evaporator and intermediate-pressure of flash tank could optimize the COP of the cycle. In this study, the effect of adding two ejectors has been investigated. Moreover, a new stream line between 2nd ejector and the rectifier has been created and evaluated. Energy balance analyses of the cycle before and after modification have been carried out. A computer simulation program has been developed to evaluate the performance of the cycles using ammonia–water solution as working fluid, operating under steady-state conditions. The results indicated that the overall COPs increment of the modified cycle are 11.56%, 12.42%, 13.46% and 14.05% at generator temperature of 80 °C, 85 °C, 90 °C, and 95 °C respectively. The results also showed that utilizing a part of streamlines of 2nd ejector decreased the heat power in the generator and hence increase the COP. Generator and condenser thermal loads after modification are found permanently less than that in the cycle before modification which indicates a significant enhancement of the proposed cycle. The results showed also that the proposed cycle is able to work under higher operation temperatures as same performance as the cycle before modification (with one ejector) under lower operation temperatures. So, this investigation could help to promote absorption cooling systems in locations of high temperature conditions.

SPICE Engine Analysis and Circuit Simulation Application Development

Electrical design automation plays an important role in nowadays electronic industry. Various commercial Simulation Program with Integrated Circuit Emphasis (SPICE) packages, such as pSpice Or CAD, have become the standard computer program for electrical simulation, with numerous copies in use worldwide. The customized simulation software with copyright need the understanding and using of SPICE engine which was open-source shortly after its birth. The inner workings of SPICE, including algorithms, data structure and code structure of SPICE were analyzed, and a engine package and application development approach were proposed. The experiments verified its feasibility and accuracy.

Determination of the parameters of a shielded busbar with a rectangular monolithic bus under steady-state conditions with sinusoidal current

A technique to determine the parameters of a shielded busbar with a rectangular monolithic bus at steady-state conditions under sinusoidal current is suggested. The resistances, inductances, magnetic inductions, induced screen current, and bus voltage are calculated taking into account the sinusoidal current frequency and bus and screen materials. The developed technique is based on electromagnetic field equations, which can be programmed using the Mathcard software for engineering calculations of the busbar parameters during computer-aided design of busbars. The validity of the technique is corroborated by the satisfactory agreement between the results of resistance and inductance calculations and the results obtained using the Elcut computer simulation program.

Energy performance of buildings in Poland on the basis of different climatic data

Typical Meteorological Years (TMY) were prepared in Poland due to the introduction of obligatory energy certification for buildings. They are based on source data collected by the Institute of Meteorology and Water Management from 1971 to 2000. Predictions indicate that until the end of the 21st century, the air temperature will increase. Therefore, the characteristics obtained with the use of TMY may differ from the energy demand of buildings used nowadays. This article compares energy demand calculated with the use of TMY and subsequent climatic data from 2001 to 2012, for three different locations in Poland. The analyses were performed with the use of the dynamic simulation computer program, for typical living quarters in a multifamily residential building with different construction and window orientation. Results obtained with the use of TMY and subsequent climatic data show that the typical years can be used for the evaluation of heating demand. However, cooling demand calculated with the use of TMY was significantly lower in comparison with the mean cooling demand for the years 2001–2012. This may distort the energy needs and indoor environment conditions in summer, and cause discomfort or unnecessary energy use in presently occupied dwellings.

Influence of ambient air relative humidity and temperature on thermal properties and unsteady thermal response characteristics of laterite wall houses

This paper presents the experimental investigation of the effect of ambient air humidity and temperature on thermal properties of the laterite rocks used in South-West coastal India. The experimental technique employed was transient plane source method in the saturated salt solution humidity controlled chamber. Experimental results showed an increase of thermal conductivity by 14.7% and specific heat by 9.15% with an increase in the relative humidity of ambient air in the hygroscopic range. A porous and ferruginous matrix of laterite was studied using a scanning electron microscope. The effects of relative humidity of the ambient air and temperature on the unsteady state thermal heat transfer characteristics such as transmittance, admittance, decrement factor, time lag, surface factor, surface factor time lag and heat capacity for different thicknesses of the laterite rock walls were investigated analytically. One dimensional heat flow equation under periodic convective boundary conditions was solved using matrix algebra and a computer simulation program which employs a cyclic admittance method was developed using MATLAB to compute unsteady state thermal characteristics. Results indicate that the decrement factor reduces by 8.35% and time lag increases by 2.88% with an increase in the relative humidity of ambient air compared to the dry state for the Indian standard laterite rock thickness.

Performance evaluation of combined ejector LiBr/H2O absorption cooling cycle

The objective of this work is to develop a computer simulation program to evaluate the performance of solar-assited combined ejector absorption (single-effect) cooling system using LiBr/H2O as a working fluid and operating under steady-state conditions. The ejector possess no moving parts and is simple and reliable, which makes it attractive for combination with single-stage absorption cycle for further improvement to the system's performance. In this research, improvement to the system is achieved by utilizing the potential kinetic energy of the ejector to enhance refrigeration efficiency. The effects of the entrainment ratio of the ejector, operating temperature, on the thermal loads, and system performance have been investigated. The results showed that the evaporator and condenser loads, post-addition of the ejector, is found to be permanently higher than that in the basic cycle, which indicates a significant enhancement of the proposed cycle and the cooling capacity of the system increasing with the increase in evaporator temperature and entrainment ratio. The COP of the modified cycle is improved by up to 60 % compared with that of the basic cycle at the given condition. This process stabilizes the refrigeration system, enhanced its function, and enabled the system to work under higher condenser temperatures.

Movement of CO<sub>2</sub> Concentration in the Room

CO2 concentration in rooms, where we spend most of our lives, has become a problem that is solved by ventilation. In buildings, where is the ventilation additionally implemented, has become a problem with distribution systems. Between professionals is solved system so called “Cascade ventilation”, where is enough to incriminated room was at the junction of the inlet and exhaust air. If this assumption will be confirmed, it will facilitate the management of air distribution systems, especially in the case of renovations. Therefore would be no implementation of ceilings, which constitute a considerable part of the budget. Cascade system is based on the principle of Dalton's Law of partial pressures. For test of this theory has been used room, where is located 8 CO2 sensors. Here was monitored the movement of CO2 concentration from resources (human) and its distribution through the room in horizontal and vertical direction. The experiment was also simplified simulated in a computer program ANSYS Fluent and simulation results are compared with measured values.

Enhancing Teaching and Learning for Basic Electrical Engineering Course Using Simulation as a Tool

One of the common difficulties faced by an entrant of an undergraduate course studying Electrical Engineering is in understanding the fundamentals of Alternating circuits (a.c.). In order to address the identified difficulty, modern engineering tool was introduced to enhance the learning in a.c. circuits as simulation tool plays an important role within the frame of teaching and learning in education across the world. With the performance of students in continuous internal examination (CIE) being less, there was a need to improvise their understanding the concepts of a.c. circuit, hence this activity was planned and implemented. The activity was initiated with the introduction to Personal computer Simulation Program with Integrated Circuit Emphasis (PSPICE) simulation tool. Simulation tool was applied in designing structured learning experiences and it was targeted to enhance teamwork competencies and understand the fundamentals of a.c. circuits. Students were trained to simulate complete and well-formed circuits which helped their learning environment suitable for supplementing traditional method of chalk and talk instruction. The activity was concluded by a feedback survey to measure the effectiveness of learning through simulation assignment on teachingl it helped them to understand theoretical concepts better. It also showed increased involvement in learning during the activity. The performance in CIE was compared with semester end examination (SEE), and it was found that the students' performance in SEE showed significant improvements in understanding the concepts of a.c. circuits. The work presented in this paper summarizes the effectiveness of simulation package used in enhancing teaching and learning in fundamental course of electrical engineering.

Simulate_CAT: A Computer Program for Post-Hoc Simulation for Computerized Adaptive Testing

This paper presents a computer software developed by the author. The software conducts post-hoc simulations for computerized adaptive testing based on real responses of examinees to paper and pencil tests under different parameters that can be defined by user. In this paper, short information is given about post-hoc simulations. After that, the working principle of the software is provided and a sample simulation with required input files is shown. And last, output files are described.

Optimization and preparation of Pt–Al2O3 double cermet as selective solar absorber coatings

To prepare high performance Pt–Al2O3 double cermet selective solar absorber coatings, a computer simulation programme has been used to calculate the appropriate complex refractive index of the Pt–Al2O3 double cermet structure. Based on the reflectance, the factors which affect the spectral selectivity of the solar absorber surfaces such as the nature of the IR reflecting metal, and the volume fraction as well as the thickness were optimized. A series of Pt–Al2O3 cermet films with different values of volume fraction and thickness were prepared onto glass and stainless steel substrates. The reflectance spectra of all the single films were in a good agreement with the calculated spectra. The measured optical constants as well as those deduced from the fitting were used as a database to optimize the selective solar absorber coating. Based on the optimized parameters, a Pt–Al2O3 double cermet with a layer stratification consisting of Mo ∼100 nm/Pt–Al2O3 ∼ 60 nm (0.39 HMVF)/Pt–Al2O3∼ 40 nm (0.19 LMVF)/Al2O3∼ 80 nm was prepared using a sputtering system at room temperature. The reflectance of the optimized Pt–Al2O3 double selective solar absorber coatings was also consistent with the theoretical calculation, the corresponding absorptance and thermal emittance were excellent: α ∼0.97 and ε ∼0.05, respectively. Considering the literature by enlarge, such experimental results overcome almost all Al2O3 based selective solar absorber coatings realized so far.

고고도핵폭발 전자기펄스 피해 분석을 위한 전산모사 연구

This paper describes computer simulation program of high-altitude electromagnetic pulse (HEMP). The HEMP is produced by the gamma rays form high-altitude nuclear explosion. The gamma rays generate a current of compton electron that leads to the production of electromagnetic fields. In case of high altitude nuclear burst, the electrical fields at the earth's surface are strong enough to be damaged for electrical and electronic device over a very much larger area. Therefore, national infrastructure will be serious damage such as power grid and communication network. In this paper introduce simulation program for calculation of HEMP and present to simulation study results of high altitude nuclear explosion experiment from U.S. and U.S.S.R.

A randomized control trial comparing use of a novel electrocardiogram simulator with traditional teaching in the acquisition of electrocardiogram interpretation skill

BackgroundAccurate interpretation of the electrocardiogram (ECG) remains an essential skill for medical students and junior doctors. While many techniques for teaching ECG interpretation are described, no single method has been shown to be superior. PurposeThis randomized control trial is the first to investigate whether teaching ECG interpretation using a computer simulator program or traditional teaching leads to improved scores in a test of ECG interpretation among medical students and postgraduate doctors immediately after and 3months following teaching. Participants' opinions of the program were assessed using a questionnaire. ConclusionsThere were no differences in ECG interpretation test scores immediately after or 3months after teaching in the lecture or simulator groups. At present therefore, there is insufficient evidence to suggest that ECG simulator programs are superior to traditional teaching.

Computerized design, generation and simulation of meshing and contact of hyperboloidal-type normal circular-arc gears

The authors proposed an approach for computerized simulation of meshing and contact of misaligned hyperboloidal-type normal circular-arc gears (HNCGs). According to local conjugate theory, the point-contact design method for HNCGs was presented, and the equations of pinion-gear tooth surfaces were deduced. Using the moving frame method, the errors and the variations were quantified, and the error-variation equations were established. Based on Hertz contact hypothesis, the contact region of pinion-gear teeth was determined, and the computerized simulation program for tooth contact was developed. By the visualization of 3D- and 2D-contact regions, the influence of misalignment errors on the shift of the bearing contact has been explored. Numerical examples that illustrate the developed theory were provided.

Effect of Air Space Thickness within the External Walls on the Dynamic Thermal Behaviour of Building Envelopes for Energy Efficient Building Construction

This paper presents the comprehensive investigation of the effect divided air space thickness within the wall on unsteady heat transfer characteristics such as thermal transmittance, thermal admittance, decrement factor and time lag of five building material walls for energy efficient building enclosure design. The five building material composite walls such as laterite stone, mud brick, cellular concrete, dense concrete and cinder concrete with total thirty configurations were studied. A computer simulation program was developed to compute unsteady heat transfer characteristics using the cyclic admittance procedure. From the results, it is observed that the decrement factor decreases with the increase in the divided air space thickness within the composite wall for all building materials. Dense concrete was observed to be the energy efficient from the lowest decrement factor point of view among five studied building materials. Dense concrete decrement factor decreases by 23.65% for 0.02 m air space thickness compared to the conventional composite wall without air space. It is also noticed that the time lag increases with the increase in the divided air space thickness within the composite wall for all building materials. Cellular concrete was observed to be the energy efficient from highest time lag perspective among five studied building materials. Cellular concrete time lag increases by 6.23% for 0.02 m air space thickness compared to the conventional composite wall without air space. The results of the study help in designing energy efficient building enclosures.

Simulation Method for Measuring Multitasking Proficiency

AbstractMultitasking is defined as conducting several tasks simultaneously. There are three characteristics of multitasking. First, multitasking has circular characteristic and demand the performance of several tasks. Second, there is a shift of attention from one task to another. Third, the performance happens in limited time. Many companies apply multitasking to make their human resources more effective and efficient. If this proficiency can be predicted, companies will be able to reduce their expenses by appropriate selection or potential review to their human resources particularly in Indonesia. Therefore, this study attempted to create computerized simulation program as the measurement methods of multitasking performance. Simulation have reflected the real situation by: the existence of various types of matter in the three sets of tasks that must be done within a certain time limit, the subject can move or choose task that they want, and the presence of dual task. Measurement conducted in a quiet room, adequate temperature and lighting, and adjustable workstation. The result of this study built practical implication that the multitasking performance measurement method by using computerized simulation could create the multitasking condition. Therefore, companies or industrial practitioners can use the simulation method to measure the multitasking proficiency of their employees.

Detailed Monte Carlo Simulation of electron transport and electron energy loss spectra.

A computer program for detailed Monte Carlo simulation of the transport of electrons with kinetic energies in the range between about 0.1 and about 500 keV in bulk materials and in thin solid films is presented. Elastic scattering is described from differential cross sections calculated by the relativistic (Dirac) partial-wave expansion method with different models of the scattering potential. Inelastic interactions are simulated from an optical-data model based on an empirical optical oscillator strength that combines optical functions of the solid with atomic photoelectric data. The generalized oscillator strength is built from the adopted optical oscillator strength by using an extension algorithm derived from Lindhard's dielectric function for a free-electron gas. It is shown that simulated backscattering fractions of electron beams from bulk (semi-infinite) specimens are in good agreement with experimental data for beam energies from 0.1 keV up to about 100 keV. Simulations also yield transmitted and backscattered fractions of electron beams on thin solid films that agree closely with measurements for different film thicknesses and incidence angles. Simulated most probable deflection angles and depth-dose distributions also agree satisfactorily with measurements. Finally, electron energy loss spectra of several elemental solids are simulated and the effects of the beam energy and the foil thickness on the signal to background and signal to noise ratios are investigated. SCANNING 38:475-491, 2016. © 2015 Wiley Periodicals, Inc.