m.hosseinpour

The salient advantages of inverters based on impedance source networks have made them proper for renewable energy conversion applications that are required to increase input DC voltage and convert it to AC energy. Switched Boost Inverters (SBI) are single-stage DC-AC power converters utilizing an active switch in the impedance network whose output voltage can be greater or less than its input DC voltage. This paper introduces a modified quasi-Z-source inverter (qZSI) structure with an active or quasi-switched boost inverter (qSBI). The suggested inverter provides a high boost factor with a small shoot-through interval and a high modulation index. The distinguished features of the suggested inverter are continuous input current and low voltage stress of switches. Moreover, despite the significant impedance source inverters, the suggested inverter is deprived of initial inrush current. Hence, the input voltage ripple is slight. Operation principles and requisite analyses have been represented, and comparisons based on various parameters with similar inverters have been carried out to showcase the superiority of the suggested inverter. Simulation results have been carried out in MATLAB\Simulink environment. The experimental results validate the accuracy and performance of the suggested inverter.

The voltage feedforward procedures at the point of common coupling (PCC) are utilized to remove current harmonics caused by grid voltage distortion in the grid-connected inverters. However, due to the time delay effect at the weak grid, the voltage feedforward at the point of common coupling can lead to instability of the grid-connected inverter. In this paper, an improved voltage feedforward procedure is presented to interconnect a photovoltaic power conditioning system to the weak grid. The stability of this system is investigated by impedance-based stability criterion in the presence of the voltage feedforward. Based on this analysis, it is suggested that the feedforward signal should be taken from the grid voltage instead of the PCC voltage. A method is introduced to extract the grid voltage from the measured PCC voltage to solve the challenge of direct detection of the grid voltage. To investigate the effectiveness of the proposed method, the photovoltaic power conditioning system based on the L filter connected to a single-phase weak grid has been simulated in Simulink MATLAB. The simulation results reveal the proper and better performance of the proposed grid voltage feedforward in attenuating the harmonics of the injected grid current, and the photovoltaic power conditioning system maintains its suitable stability in the weak grid condition.

Grid-connected inverters are considered vital elements for effectively connecting renewable energy sources and distributed generation system applications. Ripple-induced current harmonics in DC link and high switching frequency are the disadvantages of grid-connected inverters that are reduced by LCL filters. However, the intrinsic resonance in the LCL filter leads to instability of the power transmission system. As a result, suitable damping is essential for removing resonance in the LCL filters. The contribution of this paper is to improve the quality of injectable power of LCL filter-based grid-connected photovoltaic array. For this contribution, the stability of the grid-connected inverter has been investigated using active damping method, and maximum power point tracking (MPPT) for the PV array has been performed. The capacitor voltage feedforward active damping method considering computational delay is presented in this paper. By using the inverter-side current feedback beside this method, the proposed control maintains the system's low-frequency specifications independent of the grid impedance changes. It provides high harmonic rejection capability without additional compensators. Also, the number of sensors is decreased due to the alternative measurement of the capacitor voltage instead of the grid voltage for the phase lock loop (PLL). Meanwhile, maximum power point tracking is implemented using the incremental conductance (IC) technique in the boost converter. In addition, a simple and suitable computational method for designing LCL filter parameters is presented, and the system’s sensitivity is analyzed. Finally, the simulation has been implemented in MATLAB software that indicates the accurate performance of the control system in injecting the maximum power of the photovoltaic array into the grid and the highly desirable quality of the injectable current to the grid.

High yield and yield stability across a range of environmental conditions is one of the main objectives of crop breeding programs. In this study, white sugar yield stability of nine sugar beet cultivars commercially released in Iran from 2011 to 2020 with an introduced foreign cultivar as check was evaluated using randomized complete block design with four replications in six research field stations; Karaj, Ardabil, Kermanshah, Mashhad, Moghan, Miandoab, in four cropping seasons 2017-2021. The combined analysis of variance revealed that effects of genotype, year, location, and year × location, genotype × year, genotype × location and genotype × year × location were significant (p ≤ 0.01) on white sugar yield. Analysis of genotype × environment interaction showed that the first seven components were significant (p ≤ 0.01). Based on AMMI1 analysis, cv. Asia, cv. Shokoufa and cv. Arta had white sugar yield stability. Linear mixed model analysis showed that the effects of genotype and genotype × environment interaction were significant (p ≤ 0.01) on white sugare yield. Based on the BLUP method, cv. Perfecta, cv. Asia and cv. Shokoufa had the highest predicted mean value of white sugar yield. Biplot of white sugar yield with the WAASB index showed that cv. Asia, cv. Arta and cv. Shokoufa had higher sugar yield as well as higher white sugar yield stability. Ranking of sugar beet cultivars based on WAASB/white sugar yield ratio identified cv. Arta, cv. Asia and cv. Shokoufa as high yielding with white sugar yield stability. Simultaneous ranking and selection of cultivars based on 50:50 WAASB/white sugar yield ratio resulted the same. Therefore, cv. Asia followed by cv. Shokoufa and cv. Arta had relatively higher WAASBY indices. Considering the results of this study, cv. Asia, cv. Shokoufa and cv. Arta were identified as high yielding with higher white sugar yield stability.

The promotion and development of winter-sown sugar beet is one of the significant approaches for using seasonal rainfalls and saving irrigation water for its production. For this purpose, the present study was conducted to study the of genotype × environment interaction effect on white sugar yield of 11 winter season short-season sugar beet cultivars, and selection of superior cultivars in three regions of Moghan,(2019, 2020 and 2021) Torbat-e-Jam (2020 and-2021), and Joveyn (2020) using randomized complete block design with four replications. Combined analysis of variance showed that the environment, genotype and genotype × environment interaction had significant (P ≤ 0. 01) effect on white sugar yield. The GGE biplot method revealed that the first and second main components explained 83.64% of the total variation in white sugar yield. Based on the GGE biplot method, in Moghan 2021, cv. SVZB2019 and Dravos, and in Moghan 2019 and 2020, in Torbat-e-Jam 2020 and 2021 and in Joveyn 2020, cv. FDIR19B3021, cv. FDIR19B4028 and cv. SVZA2019 identified as the best cultivars with high white sugar yield and yield stability, respectively. In general, it was concluded that the environment played a significant role in phenotypic expression of the white sugar yield in the winter-sown short season sugar beet cultivars. Therefore, it would be necessary to select and release sugar beet cultivars adapted to climatic and agronomic conditions for winter sowing in target environments.

The lateral-torsional buckling (LTB) strength of cellular steel girders that were subjected to web distortion was rarely examined. Since no formulation has been presented for predicting the capacity of such beams, in the current paper an extensive numerical investigation containing 660 specimens was modeled using finite element analysis (FEA) to consider the ultimate lateral-distortional buckling (LDB) strength of such members. Then, a reliable algorithm based on the artificial neural networks (ANNs) was developed and the most accurate model was chosen to derive an efficient formula to evaluate the LDB capacity of steel cellular beams. The input and target data required in the ANN models were provided using the ANN analyzes. An attempt was made to include the proposed formula in all the variables affecting the LDB of cellular steel beams. In the next step, the validity of the proposed formula was proved by several statistical criteria, and also the most influential input variable was discussed. eventually, a comparison study was executed between the results provided by the ANN-based equation and the AS4100, EC3, and AISC codes. It was revealed that the presented equation is accurate enough and can be used by practical engineers.

Grid-connected inverter-based photovoltaic (PV) systems play an important role in Distributed Power Generation (DPG). For this application, quasi impedance source inverter is very suitable due to its ability to increase or decrease the output voltage of the inverter in a single-stage and high reliable condition. Conventionally, to remove the harmonics, which are yielded by switching the grid-connected inverter, LCL filters are utilized at the inverter output. These filters can cause some problems at the Point of Common Coupling (PCC). The aim of this paper is to improve the quality of the injected power of the photovoltaic array, which is connected to the low voltage grid by quasi-Z-source inverter (QZSI). For this purpose, a two-stage control procedure containing DC and AC stages is performed. In the DC stage, the dynamic characteristics of the quasi-Z-source network are investigated by small-signal analysis. Using the transfer functions obtained from the dynamic model, the capacitor voltage of the quasi-Z-source network is suitably controlled to generate the appropriate voltage to the grid interface inverter. In the AC stage, in order to inject high-quality current into the grid as well as eliminating the resonance peak caused by the LCL filter, a systematic procedure is used to design the PR controller parameters and active damping coefficient. Simulation of the overall system includes solar panels, maximum power point tracking algorithm, quasi-Z-source inverter, and LCL filter to model the grid-tied PV system with the possible details. Simulations are carried out in MATLAB/Simulink environment, and results depict suitable performance of the studied power conditioning system with designed parameters.

Hybrid 2/3 level inverter is a combination of three-level diode clamped inverter and conventional two-level inverter. This structure has the advantages of both two-level and three-level structures. Also, the number of switches is less than three level diode clamped inverter. In this paper, a modified structure for a hybrid 2/3 level inverter, which is based on quasi-Z-source network, is investigated. This structure improves the performance of the 2/3 level inverter and develops the voltage boost capability of the structure. Increasing the output voltage can be achieved by selecting the appropriate short-circuit interval in quasi-Z-source network. In addition, short-circuit intervals in quasi-Z-source networks allow the inverter to operate without any dead time, which results in higher quality for output AC voltage. A modified switching method is presented for the proposed inverter and the related calculations are performed. Also, a simple control scheme is proposed to balance the neutral-point of the structure and to compensate the voltage imbalance of the Quasi network’s capacitors. The proposed structure can be used to connect different distributed generation sources to an islanded load or to a low voltage grid. Simulations are carried out in MATLAB/Simulink environment and results depict suitable performance of proposed inverter.

In order to compare and determine the potential, and compatibility level of different sugar beet (Beta vulgaris L.) cultivars at different planting and harvest dates, a two years (2014-16) trial was conducted in Etka Dehloran field. In the first and second year, the trial was performed in split plot- and split-split plot based on randomized complete block design, respectively with three replications. In the first year, the main plots consisted of 15 cultivars and the planting date of 2nd October 2014 and the split plots included harvest dates of 14th and 30th April 2015. In the second year, the main plots consisted of five selected cultivars from first year trial, three planting dates (16th September, 1st and 16th October) in split plots, and three harvest dates (14th and 30th April and 14th May) in split split plots. The evaluated traits were root yield, sugar content, sugar yield, white sugar yield, Na and K content and extraction coefficient of sugar. Results of analysis of variance in the first year showed that there was a significant difference between the cultivars in terms of studied traits. According to the evaluated traits, among 15 studied cultivars and based on bolting resistance, Antek, Azaba, Silvetta, Spartak, and Sharif were superior to other cultivars; therefore, these cultivars were selected for continuous screening in the second year of the trial. In the second year, there was a significant difference between cultivars in terms of studied traits, so that the highest root yield was related to Sharif cultivar (83.32 tha-1). The highest sugar content (17.29%) and extraction coefficient of sugar (14.68%) were related to Silvata cultivar.

In this paper we introduce the concept of $tCC$-modu-les which is a proper generalizationof ($t$-)lifting modules. Let $M$ be a module over a ring $R$.We call $M$ a $tCC$-module(related to $t$-coclosed submodules) provided that for every$t$-coclosed submodule $N$ of $M$, there exists a direct summand $K$ of $M$such that $M=N+K$ and $Ncap Kll K$.We prove that a module with $(D_3)$ property is $tCC$if and only if every direct summand of $M$ is $tCC$. It is also shownthat an amply supplemented module $M$ is $tCC$ if and only if $M$ decomposed to$overline{Z}^2(M)$ and a submodule $L$ of $M$ that both of them are $tCC$.

Increasing the short circuit current due to the penetration of distributed generations (DGs) in various voltage levels and meshed topology is a basic problem in power systems. Using fault current limiter (FCL) is an efficient approach to mitigate the exceeded short circuit levels. In this paper, a new approach is presented for multiple FCLs locating to decrease short circuit levels in meshed networks with several subsystems and multi-level voltages. Modified hybrid genetic algorithm (GA) and sensitivity analysis (SA) are used to determine the type, number, location, and voltage level of FCLs. Also, an effective sensitivity index is proposed, which can reduce the search space for optimal allocation. This method suggests the optimal allocation with the least investment cost in multi-level voltages networks according to the FCL costs. The proposed method is evaluated in the IEEE 30-bus, 57-bus, and 300-bus test systems. Numerical results indicate the accuracy and efficiency of the proposed method.</div>

Nowadays, due to the widespread use of social networks, they can be used as a convenient, low-cost, and affordable tool for disseminating all kinds of information and data among the massive users of these networks. Issues such as marketing for new products, informing the public in critical situations, and disseminating medical and technological innovations are topics that have been considered by the owners of companies as well as government and private organizations. In order to achieve this goal, the methods of maximizing the speed and quality of information dissemination in social networks have been studied by researchers in various fields of science. One of the best ways to increase the speed of information diffusion is to take advantage of the social status of influential node. The role of some people within the networks is more prominent than the others, who are known by titles such as leader, important, influential, central, and vital. These people having the centrality in the social networks can have the greatest impact on the network. Identifying these people allows us to control the way of information dissemination, the spread of diseases, the more effective advertising of commercial products, or the identification of the head of different social groups. Different measures have been proposed to identify these people and to measure the centrality of nodes in a network. Identifying influential people in a network is not easy task, and the criteria for being important are varied. Therefore, there is no general index that best determines the importance of people in a network, and this index varies from one network to another and from one situation to another. In addition, whether these indexes are local or global can be a point of contention and it can produce different concepts of centrality. This paper aims to provide a new measure so-called “socio-spatial centrality” to find the central nodes in the location-based social networks, which is a linear combination of social centrality and spatial centrality. In the new proposed measure, the central node is the one that, while having more direct neighbors than the other nodes, its neighboring nodes will have a uniform and proper spatial dispersion within the given area. Degree centrality has been used to determine the social centrality and the standard distance is used to calculate the spatial centrality. By simultaneously assessing the nodes' degree and the spatial dispersion of their neighbors, the top-k nodes are identified as influential nodes. The proposed measure, along with the existing methods for measuring centralities such as degree centrality, betweenness centrality, and closeness centrality, has been applied to two real location-based social networks. The results show that the geographic coverage of the selected nodes by the socio-spatial centrality was the highest in comparison to other centrality measures, and the correlation between the output of the new centrality measure as well as the conventional centrality measures is decreasing with the increase in the number of selected nodes. Overall, evaluations show the positive impact of the proposed method on the geographic coverage maximization in location-based social networks.

Congenital anomalies are also known as birth defects and congenital disorders. Congenital anomalies occur in about 3-7% of the newborn babies worldwide. The purpose of this study was to determine the incidence of congenital anomalies and their determinants in hospitals affiliated with Isfahan University of Medical Sciences in 1395.

This cross-sectional study was conducted in all infants born in 1395. The data were analyzed with the SPSS software version 20 using Binary logistic regression.

Of 5455 births in Isfahan hospitals, 121 neonates were diagnosed with major congenital anomalies. The total incidence of major congenital anomalies was 2.2 per 100 births. The results showed a statistically significant relationship between maternal blood group, consanguinity, sex and height of infant with congenital anomalies in newborns (P <0.05). Moreover, 26.7% of all abnormalities were related to limbs and the lowest percentage was related to genetic abnormalities, digestive system, anus, and spine with an incidence of 0.7% for each.

More attention should be paid to premarital genetic counseling in order to identify the consanguinity factor as a risk factor for genetic abnormalities. Moreover, pregnant women should be educated about the timely intake of micronutrients to control abnormalities.

The current research was done with the goal of recognizing the barriers which impede women not to reach senior and middle managerial positions in NISOC. The research was an applied one in goal and a survey research in nature. The statistical population of the research included the official staff with B.A degree and above. 141 individuals were selected through stratified random sampling, using the sample’s volume formulas. Data collection instrument was the researcher initiated questionnaire, which was validated through face and content validity by the experts. The reliability of the questionnaire was calculated via Cronbach’s alpha. The collected data were tested and analyzed through applying factor analysis. The result of research showed that social, cultural, organizational, domestic and individual barriers effect on women not to promote toward senior and middle managerial positions in NISOC.