mohammad rahimzadeh

Traditionally, distribution networks are radial in topology and passive in nature. Over the past few decades, there has been tremendous interest in non-conventional energy sources, largely driven by dwindling fossil fuel supplies and increasing global warming concerns. The purpose of this research is to manage and improve the reliability of the distribution network with the approach of load response resources in the presence of scattered production resources. In this research, we also considered the effect of storage devices on the congestion and observed that the storage devices act as a load when there is no congestion in the network and draw power from the network and are charged, but in a situation where the congestion in the network is high. They act as a source of power production and are discharged and injected into the power grid, which in turn reduces congestion.

Mass erosion is the movement of rock and soil down the slope, mainly due to gravity. One of the most significant mass movements is debris flow. These are actually fast moving landslides and are a very dangerous natural disaster in mountainous areas. To control erosion and prevent sediment movement downstream, there are various biological and engineering methods available. Debris flow is most commonly controlled by check dams. The main purpose of building these dams is to control and reduce the amount of sediment entering the rivers. The backs of most dams may be filled with coarse-grained sediments and in areas with debris flows, so it is imperative to monitor how well these structures maintain different sediments. In some parts of the Nanor Baneh watershed and in the adjacent basins, there has been debris flow that has caused damage to the forests downstream. Consequently, there has also been a filling of the waterways and reservoirs of check dams. Therefore, the purpose of this study was to investigate the sedimentation granularity of check dams built in various parts of the watershed. Based on available sources, information, and maps of the basin, 58 points were identified, and their surface soil was sampled. To determine soil PSD, a hydrometry method using a 24-hour reading and sieve series was used. There are 88 gabions and masonry check dams evaluated in this research. Sediment samples were collected from each dam at two points and at two depths (a total of 57 sediment samples). After air-drying, the sediment samples were passed through a 2 mm sieve and the size distribution of particles smaller than 2 mm was determined using the hydrometric method (24-hour reading) and the same sieves as the soil samples. To determine the size distribution of particles larger than 2 mm, the sieve method (sieves with openings larger than 2 mm) was used. A comparison of the particle size distribution of soil samples upstream of the dams and the sediments behind the dams was conducted to investigate the effectiveness of these dams in trapping fine-grained and coarse-grained sediments. Finally, the gradation curves and D50 of the sediments behind the dams were examined. Based on the size distribution of particles smaller than 2 mm in the soil and sediment samples, the ratio of sand, silt, and clay in sediment samples (with mean values of 90.53, 5.45, and 4.02, respectively) varied significantly from those in the soil samples upstream of the dams. The results of D50 ratio (< 2 mm) of sediments to the soil sample upstream of check dams (average 25.92) revealed that most check dams were effective in trapping sand and larger particles, but they were less effective in keeping smaller particles in suspended sediments. Furthermore, the high D50 values for the total sediments (average 3.80) indicate that most sediments are coarse-grained. A number of check dams located in the path of the debris flow were also completely filled in one or two rainfall events, according to local evidence and field studies. Most check dams were highly effective at keeping coarse-grained sediments and preventing their movement downstream, according to sediment analysis behind them. But, these dams have little effect on trapping fine-grained sediments, and complementary methods for controlling and trapping them downstream of check dams may be needed. However, the role of these dams in reducing runoff intensity, reducing the peak flow of floods, protecting roads and residential areas downstream and many other effects cannot be ignored.

Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters of these devices. In addition, improved performance is often achieved by operating at or near the resonance point. So, this paper aims to reduce the natural frequency to match the environmental excitation frequency and increase the harvested energy. For this purpose, different geometrical and physical parameters are studied to determine the impact of each parameter. These parameters include the length, thickness, density, and Young’s modulus of each layer. The beam is considered a unimorph cantilever with rectangular configuration and the study is performed using COMSOL Multiphysics software. The results are compared with those obtained by an analytical approach. The results show that changing the parameters made the natural frequency of the system vary in the range of 20 Hz to 200 Hz and increased the output voltage up to 20 V.

Induction motors have become popular in the home appliance and industry due to their ‎advantages over other motors‏.‏‎ These motors require drives for control‏.‏‎ The use of sensorless ‎drive for induction motors is expanding due to its advantages. The advantages of sensorless ‎motor drives include increased reliability, reduced hardware complexity, lower cost ,better ‎noise immunity, and less maintenance requirements. With the advancement of industry and the ‎development of modern industry, more efficient and advanced methods are required for ‎sensorless control of induction motors. In this paper, sensorless control methods for induction ‎motors are introduced and their operation and performance in different modes are investigated. ‎The advantages and superiority of each method over other methods are examined and the ‎simulation forms of the new model reference adaptive system (MRAS)‎‏ ‏and Classical rotor flux ‎MRAS speed observer methods are given and these two methods are compared with other ‎methods.‎

In this article, a nonlinear elastic Bernoulli–Euler beam model is presented to investigate the chaotic behavior and primary and superharminic resonance of single walled carbon nanotubes embedded in a visco-elastic medium at an elevated temperature. Using the Galerkin method and fourth-order Runge-Kutta method the governing equation is solved. The bifurcation diagram and largest Lyapunov exponent are employed to detect the critical amplitude of external force of periodic and chaotic response of single walled carbon. Having known the critical values, phase portrait and Poincare maps are presented to observe the periodic and chaotic behavior of the system. Moreover, the amplitude–frequency response for the primary superharmonic resonance of system is derived with the multiple scale method to investigate the feasibility of jump phenomenon. The sensitivity of jump phenomenon are studied for the selected viscoelastic foundation parameters, detuning parameter and external amplitude load. The results show that the amplitude of external force, viscoelastic foundation parameters, detuning parameter and temperature change in the cases of high and low temperature have a significant effect on the frequency response with jump phenomenon of system. In addition, the chaotic vibration of CNT can be controlled by changing of amplitude of external force.

 Aiming to explore learners’ viewpoint regarding training program of health care providers based on CIPP model, this research was conducted on health care providers in the city of Sabzevar in 2017. This cross-sectional study was carried out on 139 health care providers working in the health centers of Sabzevar. The data were collected through a researcher-made questionnaire containing demographic characteristics and evaluation questions of training program of health care providers in four domains: context, input, process, and output.  The three modes of undesirable, slightly desirable and desirable were measured in each domain.  Through investigating learners’ viewpoint, the results of the research indicated that the situation of context and output of training program of health care providers were highly desirable, while the situation of input and process of the program were somewhat desirable. Overall, the results showed that the highest score among the four factors of the CIPP model belonged to the context factor with the mean score of 39.46 + 8.53 and the product factor with the mean score of 28.61 + 7.36 reflected the lowest score. The final results of the exploring learners’ viewpoint of training program of health care providers indicate a range of slightly desirable to desirable situation for the program. To achieve a highly desirable level, it is incumbent upon the officials to reinforce the important factors such as teaching and assessment methods to their instructors. In addition, creating a definite plan for costs and developing the accessibility of welfare facilities seem to be crucial. Finally, it is worth planning more accurately in order to increase learners’ contribution while undertaking ongoing evaluation to receive feedback for revising the teaching program.

Depression is one of the most frequent psychiatric disorders in the world with occurs with higher incidence in women. In the present study, the effect of water-alcoholic extract of Papaver rhoeas L. on forced swimming test (FST) in Swiss-Webster mice were examined.
We used Swiss-Webster mice (20-25 g) to execute FST on them. The plant extract (1, 10, 30, and 100 mg/kg) was injected to the animals 30 minutes before each session. Fluoxetine (20 mg/kg) was used as standard antidepressant drug. In another group of animals, 30 minutes after extract administration, blood samples were taken from retro-orbital sinus for corticosterone assay. Yet in third group, the drugs were injected to the animals and 30 minutes later, their activities were tested in an open field apparatus.
Our experiments showed that the extract efficiently reduced FST time both in male and female mice dose-dependently. This effect was comparable with fluoxetine. In addition, corticosterone assay indicated that plasma corticosterone in animals which received extract was higher than those amounts in fluoxetine and saline controls. Moreover, the animals did not show any motor activity deficit in all doses of the extract and fluoxetine compared to saline control.
The extract of Papaver rhoeas can reduce immobility time which is comparable to the effect of fluoxetine. Also the effect of the extract is contrary to its effects on plasma corticosterone level and or animals’ activity.

Carbapenem resistant Pseudomonas aeruginosa is a serious cause of nosocomial infections. The main purpose of the study is to determine the prevalence rate of imipenem resistant Pseudomonas aeruginosa carrying metallo- beta- lactamase (MBL) genes. 236 Pseudomonas aeruginosa isolates were collected from teaching hospitals of Ahvaz University of Medical Sciences during a period of 9 months in 2012. These strains were identified using conventional microbiological tests. The susceptibility of isolates to antibiotics were assessed using disk diffusion test. The IMP-EDTA combination disk phenotypic test was performed for detection of MBL producing strains. Finally, polymerase chain reaction (PCR) was performed to detect MBL genes, blaIMP-1, blaVIM-2 and blaSPM-1 in imipenem resistant strains. Out of 236 examined isolates, 122 isolates (51.4%) were resistant to imipenem. The IMP-EDTA combination test showed that among 122 imipenem resistant strains, 110 strains (90%) were phenotipically MBL producers. Additionally, the results of PCR method showed that 2 strains (1.6%) and 67strains (55%) of imipenem resistant Pseudomonas aeruginosa isolates contained blaVIM-2 and blaIMP-1 genes respectively. No SPM-1gene was found in the examined samples. Resistance of P. aeruginosa isolates to imipenem due to MBL enzymes is increasing in Ahavaz. Because of clinical significance of this kind of resistance, rapid detection of MBL producing strains and followed by appropriate treatment is necessary to prevent the spreading of these organisms.