s. ranjbar

In this paper, an adaptive controller for damping inter-area oscillations based on power system stabilizer and global signals is proposed. In order to investigate the nature of inter-area oscillations, a generalized SMIB model is introduced and the mechanism of inter-area oscillations is analyzed. In order to design the proposed adaptive controller, by using dynamic data gathered from the wide area measuring system, a new index is introduced to identify effective generators in damping the inter-area oscillations. Also, in order to design the adaptive controller, after determining effective generators, the stabilizer parameters are adjusted using intelligent methods. The proposed method for selecting effective stabilizers and selecting global signals is implemented on two different systems including the two-area power system consists of six synchronous generators and a practical nation IRAN power grid. Results indicate the ability of the proposed adaptive scheme to damp inter-area oscillation.

Modern power systems deal with different stability concerns due to operation near to their critical margins. Implementing the small energy resources and online islanding schemes perform as a modification scheme for increasing the system overall stability. This paper presents an adaptive approach for online detection of islanding microgirds in the presence of renewable energy resources consisting of diesel generators. For this issue, based on the concept of thevenin impedance, the microgrid impedance matrix is evaluated. In this case, considering the system angular frequency as an online index within different operating conditions, the islanding operating cases are identified. The proposed scheme uses an online non-model-based index which provides high impedance values in the case of grid-connected operating mode. Through continuous time window, the system impedance derivatives-based matrix is provided which islanding operating scenarios are estimated. In this case, considering a set of analytical evaluations, the required adaptive parameters and corresponding online adjustments are provided. The proposed approach is carried out through a modified microgrid test system consisting of synchronous generators which considering different cases studies, the proposed scheme ability is evaluated. It is revealed that through different case studies about 100 ms time duration is required to estimate an islanding operating condition which the proposed MICI index goes lower than criteria. Simulation results dedicate the effectiveness of the proposed approach for online and fast identification of islanding scenarios with respect to other corresponding techniques.

With countries throughout middle east and north Africa pursuing ambitious targets for a transition to renewable energies, the political economy of a region predominantly analyzed through the prism of fossil fuels is on the verge of radical change. As hydrocarbon prices decline, the low-cost producers of Middle East have an advantage and should be the last to leave the market. The world will demand proportionally more of the region’s oil and gas. Nearly half of the world's oil is located in Middle East, which has long been referred to as the "energy axis" of the planet. In the meanwhile, as the nations of this area progress towards the future, they have realized the need of supplying energy from these other sources, such that the utilization of renewable energy sources, such as the sun, has attracted considerable interest. This study analyzed and assessed these attractions in addition to five middle eastern nations and Turkey, which is located in middle east, close proximity to this area. The approach of comparing government incentives in the development of renewable power plants was used in this study. The final findings revealed the current status of this energy in the target nations. This study may give the target countries and other nations in the middle east with a wealth of information for the formulation of effective policies for the use of renewable resources.

Water hardness can negatively affect the efficiency of pesticides. This study aimed to determine the effect of water hardness and adjuvants added to spray solution on the efficiency of insecticides. Three insecticides, namely, malathion, acetamiprid, and spiromesifen, were mixed in well water samples at 1,869, 645, and 265 mg L-1 hardness, standard, and deionized water, and applied against the second instar nymph of Bemisia tabaci using leaf dip method. In another experiment, Zero-7 at 150 ppm and Arkan at 180 ppm as additives were added to water with 1869 and 645 mg L-1 hardness, separately. LC50 values showed that the toxicity of malathion, acetamiprid, and spiromesifen was 40, 157, and 84 times less in hard water (1,869 mg L-1 hardness) than deionized water. The efficacy of malathion, acetamiprid, and spiromesifen was 13, 65, and 39 times less when they were diluted in water with 645 mg L-1 hardness than deionized water. Malathion provided 37.28 and 18.59% greater toxicity when applied in hard water containing Zero-7 and Arkan than water without the adjuvants. The efficacy of acetamiprid was, respectively, 16.93 and 18.68% greater when it was applied in hard water containing Zero-7 and Arkan compared to water without the additives. Zero-7 and Arkan in hard water enhanced the efficacy of spiromesifen by 10.26 and 13.68% compared to water without adjuvants. Generally, the toxicity of the insecticides on B. tabaci was considerably reduced at the highest levels of water hardness. In contrast, adjuvants overcame the antagonistic effects of cations in hard water.

Transportation of fresh fruit and vegetables is complicated because it can be affected by various factors. Truck vibration is one of the most prevalent causes of mechanical damage to fresh fruit during transportation. Poor driving performance, road features, package features, truck features, package location, and fruit features are the main factors that affect truck vibration. After the harvest, the crop's quality can be maintained and cannot be improved. Thus, the globalization of fresh produce trade needs better long-distance transportation systems to deliver high-quality products to the consumer. Fruit packaging is an essential factor in reducing the mechanical damages caused by transportation. A wide-ranging of distribution environments could affect designing packages. Accurate information about the traffic and transportation status of any region helps packaging designers to produce a more precise simulation of the existing conditions. Thus, this research was conducted to analyze the vibration levels for truck transport on highway roads using multi-sensor-based computing on packaged fruit in Iran.

Towards this goal, a wireless sensor network (WSN) made of three sensor nodes with tri-axial accelerometers was designed to measure the vibration levels of a truck equipped with leaf-spring suspension on highway roads. This WSN solution enabled the sensors to be easily mounted at different locations and provided real-time data monitoring. A GPS receiver and a laptop were used to determine the location of the truck, and data analysis, receptively. To analyze the vibration data a, power spectral density function (PSD) levels were applied. A PSD function shows the strength of the variations (energy) as a function of frequency. Broadly, it shows at which frequencies variations are strong and weak. The vibration levels measurement was carried out on three trucks with leaf-spring suspension. The three selected routes represent different roads type in Iran. The reason for sampling the data acquired in the long route was to obtain information from different geographical locations on the country's roads.

The acquired data can be used in laboratory vibration tests if it is independent of the fruit type. Because the acceleration of the truck bed, unlike the one in top rows, does not depend on the fruit type and the acceleration at the end of the truck is higher than at the front, the current study focused on the vibration at the end of the truck bed. Compared to the ASTM 4728 standard, the PSD levels of the truck on highway roads were higher from 1 to 35 Hz and lower from 35 to 200 Hz. The average RMSG values calculated for lateral, longitudinal and vertical directions of heavy trucks were 0.406, 0.236, and 0.654 G, respectively. For trucks with spring suspension, the highest PSD values occurred at frequencies below 6 Hz, and the frequency range of 3-4 Hz was determined as the dominant frequency. Comparing the average RMSG (0.654 G) found with the ones mentioned in previous studies showed that the vertical vibration levels of the truck in Iran are higher than in most countries. Apart from driving quality, these results can be explained by the type of suspension system, amount of load, and road quality.

In sum, the results can be used to simulate the truck transport conditions by programmable vibration simulators to reproduce the vibration conditions for package testing on Iran roads. The findings are highly interested in improving packaging design, reducing fruit damage, maintaining shelf life, smart transportation, and related industries. Thus, potential future works are lab simulations, optimizations of packages, and the development of a real-time vibration monitoring system.

Hypertension is one of the major problems in the world. Adherence to treatment of patients with hypertension is insufficient, and there are conflicting results regarding the effect of peer education. Therefore, this study was conducted to compare the effect of training by peers and health care staff on adherence to treatment in patients with hypertension.

This clinical trial was done on patients with hypertension in Yasuj, Iran, in 2017. Two hundred sixty-four eligible individuals were selected using convenience sampling and randomly assigned to three peers, health center staff, and control groups (88 people in each group). The data collection tool was a researcher-made questionnaire assessing adherence to treatment of patients with hypertension, psychometrically evaluated. The questionnaire was completed by three groups before, after, and two months after the intervention by participants. Five education sessions were conducted weekly by the peer group for intervention group 1 and the health care personnel for intervention group 2. Data were analyzed by SPSS 24, using Repeated Measures Analysis of Variance, Chi-square test, and Bonferroni test.

Both educational interventions by peers and health care personnel effectively increased adherence to treatment of patients with hypertension (p<0.05). Although at the end of the intervention, education by peers and health care staff had the same effect on increasing treatment adherence, two months after the intervention, peer education on adherence to treatment was greater than education by health center staff.

Peer education also increases adherence to treatment in patients with hypertension; thus, due to its cost-effectiveness and the lack of special equipment, peer education is recommended as a suitable approach.

Vitamin D deficiency is a major health concern in the world countries such as Iran. This study was carried out to compare effects of vitamin D supplements in doses of 50000 IU/month and 1000 IU/day on serum 25-hydroxy vitamin D (25(OH)D).

In this triple-blind randomized controlled trial, 90 college students with serum 25(OH)D levels < 30 ng/ml were divided into three major groups of 30 to receive vitamin D3 supplements of either 50000 IU/month and 1000 IU/day or placebos. Intervention was carried out for 12 weeks. Levels of serum 25(OH)D, calcium, phosphorus and parathyroid hormone were assessed as well as weight, waist circumference and blood pressure at the baseline and end of the intervention.

At the end of study, levels of 25(OH)D increased in all groups. This increase was higher in 50000 IU group, compared to 1000 IU group (27.0 ±8.6 instead of 21.2 ng/ml ±9.7, p = 0.01) and in 1000 IU group, compared to placebo group (21.2 ±9.7 instead of 14.0 ng/ml ±11.7, p = 0.04). Parathyroid hormone significantly decreased in all groups with no significant differences between the groups. Intra-group changes were not statistically significant for calcium, phosphorus, weight, waist circumference and blood pressure. Comparison of changes based on 100 IU supplement intake did not show significant differences in 25(OH)D levels between the two supplemental groups. However, decrease of parathyroid hormone was greater in 1000 IU group, compared to 50000 IU group (-2.7 ±4.2 instead of -1.3 pg/ml ±2.1, p = 0.01).

Monthly and daily supplements improved 25(OH)D levels. Based on 100 IU supplement intake, daily supplements caused further decreased parathyroid hormone, which suggested that daily supplementation might include more benefits than monthly supplementaion.

In this paper, we investigate optical properties of silver pyramid nanostructures (SPNs) by means of discrete dipole approximation (DDA), when these nanoparticles are embedded into the water. Absorption, scattering and extinction cross-sections of the SPNs were calculated by change of incident wavelength in visible and near infra-red region. Moreover, height, wavelength and full width at half maximum (FWHM) of extinction cross-section peaks (due to plasmon resonances) were studied by change of nanostructure's size and dielectric constant of medium. Our results show that, there are only two peaks of dipole and quadruple modes in this spectrum.

In the present research, for the development of Fars province minimum temperature atlas, minimum daily temperature data of 20 evaporative stations of Fars Regional Water Organization and five synoptic stations of Fars Meteorological Organization were used. At first, two starting times were selected for all of the stations. The first was the first day of Farvardin for analyzing the spring frost and the secend was the first day of Mehr for analyzing the autumn and winter frost. Also, the temperature range of 0 to –1.5 was classified as mild frost or freeze, the temperature range of -1.5 to –3 as the moderate frost or freeze and temperature below –3 as severe frost or freeze. The data of minimum temperatures, the first and the last days in which the three temperature ranges occurred and the day of the lowest temperature based on the two starting times were recorded. The selected number of days (dates) were fitted to the distribution functions by SMADA software and the best distribution function was identified using the statistical parameter Root Mean Square. The best fitted distribution functions were Pearson type III and log Pearson type III. Then, based on the fitted distribution function, the number of days for the occurrence of the first and last frost and number of days for the occurrence of the first lowest temperature were determined at 50 and 70% probability levels. Finally, each of these occurrence dates was plotted with Surfer software using the geographical positions of each station (longitude and latitude) for Fars province. Based on these plotted maps, the best days of planting and harvesting of the crops can be determined throughout the Fars province.