نشریه کارافن
سال بیستم شماره 61 (بهار 1402)

The use of photovoltaic panels in power grids around the world is expanding. If these panels are equipped with a solar tracker, they produce the maximum amount of possible power every hour. But since the use of these trackers increases investment and maintenance costs, many of these panels are installed without using trackers. Fixed panels are generally installed in such a way that the maximum annual output power is generated. Considering the sharp increase in load during peak hours, it is necessary to investigate the possibility of increasing the participation of fixed photovoltaic power plants in providing peak load. For this purpose, the design of the photovoltaic power plant has been studied in two scenarios. In the first scenario, the photovoltaic panels are installed based on the increase in annual output power generation, and in the second scenario, the photovoltaic panels are installed based on the increase in power generation during the peak hours of the day. The obtained results show that although the second approach has led to a decrease in the total annual power generation by photovoltaic panels, the participation of photovoltaic power plants in supplying the peak load is increased, and the amount of network annual losses is decreased than the first approach.

The petrochemical industry is in the continuation of the oil and gas industry chain. The innovation projects of a company must be consistent with its resources and goals, the purpose of this study was to present a model to improve the capacity of absorbing green technological innovations in the Iranian petrochemical industry. This research was applied in terms of integrated method (qualitative-quantitative) and in terms of purpose and was carried out in 2022. The statistical population of this research was the petrochemical industry companies, which were used to draw causal circles and model the experts in this field using the snowball method. To collect information in the qualitative part of interviews with experts(13 experts) and in the quantitative part, the data obtained from the first part were analyzed in the form of quantitative analysis. The data analysis stage is a multi-stage process during which the data obtained through the use of collection tools in the statistical sample (community) are summarized, coded and categorized and finally processed to establish the basis for various types of analysis. Data and relationships between these data are provided in order to test the hypotheses. In the qualitative part, the coding method was used, and in the quantitative part, Vensim software version 3.7 and and Super decision version 2 were used.was used. The findings showed that structural barriers, legal barriers, attitudinal barriers and infrastructural barriers of the company have an effect on the capacity to absorb technological innovations in the Iranian petrochemical industry.

Electricity distribution network delivers voltage 220V to single phase customers. In weak distribution system, the length of feeders is long so the end of feeders is faced with excessive voltage drop. Compensating for this voltage drop by constructing medium voltage power system and installing new distribution substations is not cost effective. Especially in rural areas where the prospect of development and increase in subscribers is unlikely. Therefore, other flexible and low-cost solutions should be considered. In this research, to compensate for voltage drop, a small group of home subscribers who have voltage drop due to their distance from the distribution substation, a semi-industrial model of solid-state voltage regulator is designed and manufactured. In this structure, dry autotransformers with nominal power of 15KVA will be used as single-phase (or three-phase). The low-voltage autotransformer taps are changed by the use of triac semiconductor switches with voltage closed-loop control. To show the efficiency of this method, a 500VA laboratory sample was made using 12 triacs with 40A rated current, from which successful results were obtained. The measurement results show that this equipment can limit the voltage changes to the range of 0.95 to 1.05 of the nominal value while also not affecting the quality of power. The semi-industrial version of this voltage regulator has been manufactured and successfully tested, in which appropriate protection functions are embedded for operational use in power systems.

Nowadays, due to the increase in the amount of environmental pollutants and the electricity production price of energy carriers, the use of renewable energy sources for electricity production is increasing. Among renewable energy systems, photovoltaic systems, due to their stability, long lifetime, and low maintenance costs, are very popular. Utilization of these systems requires an accurate evaluation and understanding of various aspects of their performance, and ignoring this important issue is not only ineffective, but it may also lead to irrecoverable economic costs. To prevent this problem, several simulator applications are available for pre-construction testing of power generation units. In this paper, in order to simulate and assess the possibility of installing a photovoltaic production unit in the study environment, PVsyst application and accurate meteorological data such as annual radiation rate and environmental temperature have been used. Since solar arrays are installed in both movable and fixed forms, in this paper, the performance of both is examined separately and the model that had lower losses in practice and consequently higher efficiency is introduced. The simulation results showed that in the study environment, using the fixed type of solar panel for generating electrical energy is more appropriate than using the mobile type.

In addition to all the advantages of renewable energies, their use in the form of wind turbines and solar cells in power grids to provide the required power can be considered a negative factor from the point of view of stability in power systems. The main aim of this paper is design of wide-area damping controller (WADC) in converter of battery energy storage system connected to renewable energy sources including photovoltaic and permanent magnet synchronous generator (PMSG) in large-scale power system. The proposed approach is based on Free-Weighting Matrices(FWM). At first, by using optimal control theory based on delay-dependent feedback, a set of constraints related to linear matrix inequality(LMI) are formulated. Then, for obtaining parameters of optimal control that can tolerate maximum time delay, the FWM approach is employed to solve time dependent on the time delay. In this regard, an iterative algorithm based on conical complement linearization has been also presented to search for parameters of optimal control. Finally, non-linear simulation is implemented on 5-area 16-machine power system in MATLAB. The simulation results clearly demonstrate the desirability of the proposed controller under existing uncertainties.

Most of the profits from the production of agricultural products are spent on energy costs of inputs (including machinery, irrigation, fertilizers, etc.). In this research, energy consumption analysis, emission of greenhouse gases and their optimization from Data Envelopment Analysis (DEA) methods in sugar beet production from the dominant products of Naghadeh city in Azerbaijan Gharbi province were investigated. In this study, efficient and inefficient units were identified. The results showed that the total energy input in the production of sugar beet products is 37548.371 Mj/ha. The highest consumption of inputs in sugar beet is fuel input with 38.81% and chemical fertilizers with 33.49%. Also, the emission of greenhouse gases in the production of sugar beet products was calculated to be 1319 kg/ha. Fuel was the most widely used input at 54% in sugar beet. Energy efficiency was also equal to 1.83. The results of optimization of energy consumption and emission of pollution using data envelopment analysis showed that 4.69% of the total energy of sugar beet in Naghadeh city can be stored. Also, envelopment analysis of the data reduced the greenhouse gases of sugar beet by 246.25 kg of carbon dioxide per hectare.

In the present study, using axisymmetric numerical simulation based on the Euler-Euler method, subcooled flow boiling of pure water in a pipe was investigated and the local and average heat transfer coefficient, local and average vapor volume fraction, and local and average wall temperature under different boundary conditions have been investigated. According to the results obtained from the numerical simulations, the wall temperature increases with increasing pressure. Also, the vapor volume fraction has decreased with increasing pressure. The effect of heat flux on wall temperature and vapor volume fraction is greater than all other boundary conditions. Although numerical approaches give a complete insight into the flow pattern and thermal characteristics, the simulation of complex multiphase flows requires high computational resources and is very time-consuming. In conclusion, we present a deep learning approach based on artificial neural networks to predict the mentioned parameters in pure water. The models presented in the present study accurately predict the output parameters using the hyperparameter tuning method. The results of the prediction models show that these models are able to accurately predict the objective functions with an average absolute error of less than 2.5% and a coefficient of determination greater than 0.9.

Vehicle stability and handling are among the topics investigated widely in automotive industry. Meanwhile, vehicle lateral dynamic behavior plays a pivotal role in vehicle stability and handling. The present study aims to investigate that how the lateral dynamic response of the vehicle is affected by variation of the parameters and to what extent is that affection. To this end, firstly, the dynamic response of the vehicle to the steering angle is simulated by means of lateral dynamics equations of motion. Then, in two different maneuvers, as the affecting parameters are changed, the dynamic response of the vehicle is evaluated. In the current paper, variation of vehicle mass, moment of inertia, and gravity center are considered. In addition, investigations are performed using two models, i.e., 2 degree-of-freedom bicycle model and a high fidelity model proposed in Carsim software package, in order to identify that how the model selection can affect the outcome. Results indicate that in one of the maneuvers, vehicle response evidently changes by varying the parameters, whereas, in the other maneuver, no significant changes observed.

The cold roll forming is one of the common processes to form metal profiles in the industry. Due to the nature of the bending deformation in cold roll forming process, spring-back is one of the most important defects. In order to compensate the spring-back, the amount of spring-back must be correctly predicted. In this article, the effect of the hole and its position on the spring-back has been investigated by experimental and numerical methods. three channel section profiles made of St12 and thickness of 1 mm, without hole, with circular holes on the bend area and with holes on the flange were used. Cold roll forming was done in three stations with a fixed bending radius pattern with 15 degree bending in each forming station and numerical solution using Abaqus finite element software. The results indicate that there is a relationship between the amount of spring-back and the position of the hole in such a way that the amount of spring-back in hole on the bend area profile is 9% more than the hole-less profile and in hole on the flange profile is 16% less than hole-less profile. Also, according to finite elements results, it was observed that the amount of equivalent strain in the bend area of the profile with holes on the bend area is 20% less and in the profile with holes near the bend area is 16% more than the profile without holes, which can justify the difference observed in the amount of spring-back.

There are different categories of materials like elastomers, polymers, hydrogel foams, and biological tissues that respond with large deformations (in comparison with solid metals) while under small stresses. By using a strain energy density function, it is possible to investigate their non-linear mechanical behavior. In the current study a strain energy density function for transversely hyperelastic material is proposed and its coefficients are approximated (using least square error) by incorporating experimental results into the model. Expected deviations between the proposed model and the experimental results for the fibrous layer of articular capsule, ligaments, and the human knee tendos are bounded by 1e-5 MPa and 1e-7 Mpa respectively. The proposed strain energy density function is a function of two invariants with more accuracy than the proposed one by Qiu and Pence, Merodio and Ogden and Guo et al. which uses a strain energy density function with only one invariant. Using the strain energy density function, a closed analytical form independent of integrals terms for expressing the stress within a thick-walled cylindrical tube for transversely isotropic hyperelastic materials, that has similar mechanical behavior to that of a human artery, is derived. The analysis for the stress, deformations is done considering artery like structures with both ends open and closed while under axial loads.

Nowadays, robots are employed widely, and they are utilized in many operations and occupations. They are not just luxury devices or entertainment tools, but they are used to reduce costs and increase the accuracy of functions such as robotic surgery or agricultural harvesting in countries with high labor costs. One type of robot is a wire-driven robot developed recently for industrial inspections, laparoscopic surgeries, and crop harvesting. This type of robot has a limited range of payloads supporting and accuracy in positioning, but simple structure and adaptability by working space lead to focus by researchers. The current paper introduces a wire-driven flexible robot where its kinematic and dynamic models are presented based on the Euler-Bernoulli beam theory. Regards to stated models, a proportional-derivative-integrator controller (PID) is employed for this dynamic system. In addition, an adaptive neuro controller with two hidden layers and five neurons was established for that. Various functions such as step, ramp, sinusoidal, random, and square signals are exposed to both controllers as inputs to study their stability and accuracy. The adaptive neuro controller responses are as good as the PID controller though in the face of random and sinusoidal inputs did not show better performance.

The composition of the coating used In the piston ring has a great effect on friction and wear in combustion engines. In the present study, the wear behavior of three samples of TU3 engine ring with hard chromium, chromium nitride, and diamond-like carbon coatings were studied and compared. Various coating properties including chemical composition, microstructure, thickness, roughness, and hardness were studied. Also, the microstructure and wear mechanism was studied using a scanning electron microscope (SEM) and energy dispersive analysis (EDX). A reciprocating wear test device was used to check the wear behavior of the piston rings. In the end, an attempt was made to investigate the relationship between properties and tribological behavior created in piston rings. The high hardness and the presence of graphite as a solid lubricant were among the most important factors for the appropriate wear behavior of the piston ring with a diamond-like carbon coating. Due to the lack of complexity and high hardness, the piston ring with hard chromium coating has a sticky wear mechanism and does not show proper wear behavior. The worst wear behavior was observed in the piston ring sample with chromium coating. Low adhesion to the substrate, low hardness, high roughness and thickness, and single layer can be considered as the most important factors of inappropriate wear behavior of this sample. Also, the results showed that the wear resistance of diamond-like carbon coating is almost four times that of chromium nitride coating and six times that of hard chromium.

Employing lightweight steels in the transportation industry, especially the automotive industry, has received lots of attention in today’s time, and much research has been done to replace the low carbon steel used in the transportation industry with lighter materials. In this regard, in the present study, a new class of lightweight steels called architectured steels involving alternating layered structure of steel and aluminum was produced. In this process cold rolling process was employed to make a connection between a simple low carbon steel and 6061 aluminum alloy. In order to improve the inter-layer connection and properties of the product, the prepared samples were subjected to annealing treatment at different time (30-120 min) and temperatures (400-500° C). Finally, after examining the conditions of different annealing processes, the best cycle to achieve an appropriate combination of strength and ductility was determined. In the end, the best mechanical properties (610 MPa UTS and 16.1% elongation) was obtained in the specimen annealed at 400°C for 90 min.

The aim of this research is to design and fabricate a natural dye-sensitized solar cell using a semi-solid electrolyte and substituting a platinum electrode with Zirconium oxide/Tungsten oxide nanorods (ZrO2/WO2NR) nanocomposite for reducing the costs. To prepare the semi-solid electrolyte, a combination of three substances, cesium iodide (CsI), tin iodide (SnI) and tin fluoride (SnF2) were used. The result of this compound is cesium tin iodide (CsSnI3-xFx), which due to the high mobility of the cavity equal to 585 cm2V-1S-1 and the ability to dissolve in organic solvents, can be a good alternative to liquid electrolyte replacement. The photoanode structure was examined by scanning electron microscopy. The effect of black and simple henna was investigated by UV-visible spectroscopy to select the dye. The counter electrode was fabricated by ZrO2/WO2NR nanocomposite by micro-spray method. The results showed that natural henna dye offers better performance with the peak absorption at 665 nm. The utilization of ZrO2/WO2NR nanocomposite, in addition to good catalytic properties, also showed a voltammetric cycle similar to platinum, which results in longer life and stabilization of output power over the time. The performance evaluation of the fabricated sample indicated the open circuit voltage of 0.17 V, the short circuit current of 4.08 mA and the efficiency of 0.95%, which is 2 times higher than in comparison with liquid electrolyte-based cells.

Disorders of the autonomic nervous system (ANS) complicate the clinical course in patients with acute stroke. This research presents a model that can be used to detect any deficiency in the autonomic nervous system and show its relationship with the occurrence of stroke. The data used in the present research is provided by using the studies conducted on the functioning of the autonomic nervous system in patients suffering from stroke (brainstem). The focus of this research is to examine the studies that present the function of the autonomic nervous system in the early period after stroke. This study determines the effect of stroke location on autonomic nervous system function. And by examining the vital parameters of the body, he tries to relate them to the functioning of the autonomic nervous system. In the final step, using other research, vital data associated with the functioning of the autonomic nervous system is identified. Then, using these data and using a fuzzy system based on Takagi-Sugno’s logic, the correct functioning of the autonomic nervous system is estimated with parameters in the heart, brain, and blood plasma measurements. This estimate helps to identify the patient's condition and his proximity and distance to stroke.

Pretrained language models are very important because of their application in issues related to natural language processing. Language models such as BERT have become more popular among researchers. Due to the focus of these language models on English, other languages are limited to some multilingual models. In this article, the VarzeshiBERT language model is presented for the purpose of Persian sports analysis in topics related to this linguistic field. This language model is based on the Bert language model and was trained using the collected dataset. Three problems are used to evaluate the new language model: sentiment analysis, named entity recognition and text infilling. In order to train this language model, due to the lack of a suitable dataset, a wide range of sports events and news in the Farsi language has been prepared from several online sources. Due to the specialization of this model and compared to the language models presented for the Persian language, this model has provided better results in all three problems. This model has the best performance with 71.7% and 95.2% in text infilling and Named Entity Recognition, respectively. In sentiment analysis, the sports model has brought better results. These results show that using a language model related to any specialized field will have better results compared to language models related to the general field of texts.

Ion flotation is a method for the metal ions recovery from aqueous solutions. In this method, the metal ions in floating froth are recovered. In hydrometallurgical methods for extracting copper from leach solution, firstly, solution is recovered by using solvent extraction method (SX), then copper is recovered by using Electrowining method. SX is the most common method; nevertheless, there is limitation in input minimum concentration. As a result, diluted solution cannot be concentrated with this method. In this study, the use ofion flotation method for copper recovery from a diluted leach solution from copper Mine in Qom is investigated. The Experiments were carried out on the Mine diluted solution using Denver mechanical cell types, in PH value of 6, 9 and 12 when the copper ion concentration was 10 ppm. ethanol and methyl iso-butyl carbonyl (MIBC) were used as frother. hexa decyl trimethyl ammonium bromide (HTAB) and Sodium dodesyl sulfate (SDS) were used as collector. The efficiency of this method was evaluated by measuring copper recovery. Best results were obtained at pH value of 12, by using HTAB as collector with amount of 100 ppm and 0.1% (V/V) MIBC as frother. Under these circumstances, copper recovery, have been reported 82.3%.

Doxorubicin is an anticancer drug that prevents the growth and progression of cancer cells. Considering that in some samples the amount of doxorubicin is very low, so choosing a preconcentrative method is very important and necessary. In this study, dispersive solid phase extraction, by using graphen oxide nano particles, was used as an efficient preconcentration method.Different affecting parameters, such as adsorption time, desorption time, amounts of adsorber, type and volume of organic solvent (desorbing solvent) and pH were investigated and optimized.After optimization of the experimental conditions, doxorubicin concentration was measured at wavelength of 478.5 nm. The calibration curve was linear in the 0.06 to 6.5 mgL-1 doxorubicin concentration range, and the detection limit (at an S/N ratio of 3) was 0.018 mgL⁻¹. Relative standard deviation (RSD%) for ten replicate measurement of doxorubicin solution was 2.8%.The enrichment factor and recovery of the extraction method were 58 and 78% respectively. The proposed method was applied to the determination of doxorubicin in real samples with satisfactory analytical results.

Composite shear wall consisting of steel sheet with reinforced concrete cover is one of the most common systems resistant to lateral loads in tall structures. The main purpose of this study is to investigation the effect of reinforced concrete cover, steel sheet thickness, door and window opening on the seismic behavior of steel frame with composite shear wall. For this purpose, in the present study, after validation of numerical modeling, 19 specimens of composite steel shear wall with a height of 3.2m and a span length of 5m are modeled. The results of this study show that the utimate strength, stiffness, dissipated energy and ductility in the model with reinforced concrete cover without opening and with a steel sheet with a thickness of 15 mm, respectively 12.24, 63.78, 7.82 and 4.37 times the reference model and in the same model without reinforced concrete cover, these values are 8, 41.61, 4.46 and 6.24 times the reference model, respectively. In other words, the reinforced concrete cover, due to the prevention of buckling of the steel sheet due to compressive force, has increased the utimate strength, dissipated energy and ductility. Also, in reinforced concrete cover, increasing the thickness of the steel sheet from 10 to 15 mm has little effect on the utimate strength.

Evaluation of the design concept is known as one of the main phases in the development of product production because it determines the course of activities in the first stage of product design. However, usually at this stage the information is subjective and depends on the judgment of experts. How to control and manage these individual uncertainties is considered an important issue. Therefore, this research presents a systematic evaluation method based on integrating the analytic hierarchy process and the Technique of Order Preference by Similarity to Ideal Solution, which is known as the TOPSIS method, and in this article, rough numbers is used to evaluate the concept of design in a subjective environment. Rough numbers are used with the purpose of introducing the preferences and subjective judgments of people in the analytic hierarchy process. Then, an improved rough number is also provided by TOPSIS method to rank the options. To demonstrate the validity and effectiveness of the proposed method, this method is being implemented at the Unilever Cosmetics and Hygiene Company and designed to design the above-mentioned OMO concentrate washing powder to indicate that the proposed method can effectively increase the uncertainty in the assessment of the design concept under uncertainty conditions.

Today, simulation studies have found many applications in industrial engineering and other sciences. In today's competitive market, companies and organizations are trying to increase productivity and efficiency by designing and modeling effective and efficient system operations. In this regard, to reduce evaluation time and reduce costs, use similar methods. Graphic construction in software environment and the use of statistical software are instructive and efficient. The purpose of this research was to reduce costs, increase production, reduce the unemployment time of operators and machines, as well as reduce inventories between the production processes. Simulation was used to achieve these goals. The steps of conducting the research are summarized as follows. First, the layout in the factory was identified, in the next step, timing was done for the devices and operators. Real data was transferred from the production line to the software environment and then 15 different scenarios were designed and simulated in the software environment. Then, using TOPSIS method, the best scenario was selected and using the experts and factory managers, the validity of the model was confirmed and then the model Execution and simulation results were recorded.

Flight delays are one of the most important and pervasive problems in the aviation industry. One way to reduce flight delays is to use backup planes. In previous research, less attention has been paid to the issue of backup aircraft and especially the location of their deployment in order to reduce air traffic delays. Therefore, in this research, an agent-based modelling and simulation is used to find the optimum deployment location of backup aircrafts. The main objectives of this study were to investigate the effect of locating backup aircraft as well as the effect of increasing their number in reducing the average delay time of air flights. In modeling, three scenarios were examined based on the number of backup aircraft. The first, second and third scenario consisted of one, two and three backup aircrafts, respectively. The results showed 26% and 29% increase in the number of backup aircraft from one to two aircrafts and from two to three aircrafts in reducing the average delay time. In addition, in each of the scenarios, the difference between the worst and best locations found for the deployment of backup aircrafts and its impact on latency was examined. This effect was 70%, 77% and 84% in the first, second and third scenarios, respectively. These huge differences showed the great impact of optimal location of the deployment centers in reducing the flight delays.

Economical and resilient operation of energy systems has always been one of the important and main priorities of the energy systems operators. However, with the progress made in various fields of energy systems, especially power systems, the discussion of resilience and reduction of energy not supplied has become more important. In other words, in addition to the supply of energy consumers, the issue of energy welfare is raised which is a function of the energy not supplied index. And according to that, the consumer expects the energy receives with maximum possible power quality and minimum outage. Therefore, in this paper a bi-objective optimization model is proposed to improve the economic performance of the energy hub system and to improve the resilience of electric consumers under adverse weather conditions, in which the operational cost of the hub energy is minimized and on the other hand, the consumer welfare index, which is a function of the energy not supplied index of the system, has been maximized. It is assumed that outage rate of electrical lines can be affected by weather conditions. To solve the optimization problem, the epsilon constraint method has been used and in the following, the fuzzy Max-Min method is used to select the optimal solution from among the set of solutions.