101 research outputs found

    Fault tolerant vector control of five-phase permanent magnet motors

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    Equipped with appropriate control strategies, permanent magnet (PM) machines are becoming one of the most flexible types of actuators for many industrial applications. Among different types of PM machines, five-phase BLDC machines are very interesting in fault tolerant applications of PM drives. Torque improvement in five-phase BLDC machines can be accomplished by optimizing their mechanical structure or by enhancing their controlling methods. New current controllers are proposed in this thesis to improve the quality of generated torque under normal operations of five-phase BLDC machines. Proposed current controllers are based on combination of predictive deadbeat controlling strategy and Extended Kalman Filter estimation. These controllers will be the basis for accurate faulty operation of the motor. Operation of five-phase BLDC machines under faulty conditions has also been considered in this study. To improve the generated torque under faulty conditions, both amplitude and phase angle of fundamental and third current harmonics are globally optimized for the remaining healthy phases. Under faulty conditions, appropriate reference currents of a five-phase BLDC machine have oscillating dynamics both in phase and rotating reference frames. As a result, the implemented current controllers under these conditions should be robust and fast. Predictive deadbeat controllers are also proposed for faulty conditions of five-phase BLDC machines. Fault tolerant five-phase BLDC machines are very interesting in automotive applications such as electrical vehicles and more electric aircraft. In addition, these devices are gaining more importance in other fields such as power generation in wind turbines. In all of these applications, the efficiency of PM machine is of most importance. The efficiency of a typical five-phase BLDC machine is evaluated in this thesis for normal and different faulty conditions. Experimental evaluations are always conducted to verify the theoretical developments. These developments include proposed controlling methods, optimized reference currents, and simulated efficiency of five-phase BLDC machine under different operational conditions

    Knowledge, attitude and practice of urban and ruarl households towards principles of nutrition in Iran: results of NUTRIKAP Survey.

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    Background: The aim of this study was to assess knowledge, attitude and practice of urban and rural households toward principles of nutrition in Iran. Methods: The study population was Iranian households who live in rural and urban areas in all provinces of the country. The sampling method at households’ level in each province was single stage cluster sampling with equal size clusters. The incumbent data was collected by a structured questionnaire and through the interview with the eligible subject in each household. Results: A total of 14,136 Iranian households were selected as total sample size, 9,149 urban households, and 4,987 rural households. Around 57.2% of urban and 49.5% of rural households was aware of food groups. Respectively in urban and rural households, about 35.1% and 39.7% had correct knowledge toward roles of food groups. Approximately 41.5% and 39.9% of households had accurate knowledge about reason of food eating in urban and rural areas, respectively. The results showed that 79.6% of them had favorable attitudes. The most of the households consumed red meat and poultry weekly whereas fish was eaten rarely. Fruits, vegetables and dairy were consumed daily in the most of households. Sugar intake was daily in the most of households and cream and butter intake was weekly. Conclusion: The most of households had moderate knowledge and good attitudes. Practice of families about food consumption was good. The results of this study can be used for proper intervention for improving of health society

    Comparison of Sampling Methods Used to Evaluate Forest Soil Bulk Density

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    The objective of this study was to compare forest soil bulk density values obtained through conventional sampling methods such as the volumetric ring (VR: diameter 5 cm, length 10 cm) and paraffin sealed clod (PSC), with a variation of the VR, where rectangular boxes (RB) of four different dimensions were used. Sampling transects were established on a machine operating trail located in a beech (Fagus orientalis Lipsky) stand in Northern Iran. At each transect, three soil samples were collected at three different locations. Samples from different methods were spaced by a 50 cm distance to avoid direct interactions. The soil class of our study area was Combisols according to the WRB classification with a clay texture. Soil bulk density differed significantly between the three sampling methods. The lowest values were obtained with the RB (average 1.25 g cm-3), followed by the VR (average 1.40 g cm-3), and lastly the PSC (average 1.52 g cm-3). The values obtained with four variations of the RB method ranged from 1.22 to 1.28 g cm-3 and were not found significantly different. When soil bulk density was calculated after the removal of the weight and volume of roots included in the samples, the values were determined to be higher than before but with the same range of magnitude. The lowest coefficient of variation was found for RB4 (CV=2.3%), while the highest values were observed for VR and RB1 (CV=5.7%)

    Combined Effects of Skidding Direction, Skid Trail Slope and Traffic Frequency on Soil Disturbance in North Mountainous Forest of Iran

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    Harvest traffic with heavy equipment causes damage to forest soils. Whereas increased soil damage has been reported with increasing harvest equipment traffic and on increasing slope gradients, it is unclear how much soil damage is caused by different directions of skidding. We examined the effects of traffic frequency, skid trail slope and skidding direction on the dry bulk density and total porosity of skidding trail soil in an Iranian temperate forest. The studied treatments included combinations of three different traffic frequencies (3, 7, and 12 passes of a rubber-tired skidder), three levels of slope (20%) and two skidding directions (uphill and downhill). The impact on soil properties was greatest during the skidder initial passes. On steep slopes, only three skidder passes were required to cause substantial increases in soil bulk density relative to control plots, regardless of skidding direction. Independently of the traffic frequency and trail slope, uphill skidding caused substantially greater increases in dry bulk density and greater decreases in soil porosity than did downhill skidding. Total porosity was significantly lower on steep slopes than on gentle slopes regardless of traffic intensity and skidding direction. In general, fewer uphill skidder passes were required to achieve substantial soil disturbance than was the case for downhill skidding, possibly because skidders move more slowly when travelling upwards and uphill skidding places greater loads on the skidder rear axle

    Association analysis of-416G > C polymorphism of T-cell immunoglobulin and mucin domain-1 gene with asthma in Iran

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    TIM (T-cell immunoglobulin (Ig) and mucin domain)-1, one of the members of TIM family, expresses on Th2 cells and promotes the production of Th2 signature cytokines. This can increase a series of responses in these cells which could be one of the causes of asthma or asthma-related phenotypes. The aim of this study was to investigate whether a TIM-1 promoter single nucleotide polymorphism (SNP), -416G>C, is associated with asthma in Iranian population. In this case-control study, existence of the -416G>C polymorphism was assessed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in 300 patients with asthma (97 atopic, 203 nonatopic) and 309 healthy volunteers. Additionally, the relationship between these polymorphism genotypes and total serum IgE levels in this Iranian population was evaluated. We discovered a significant association between the -416G>C polymorphism and atopic asthma susceptibility in the population, but this SNP showed no connection with nonatopic asthma (PC polymorphism in TIM-1 gene could be a predisposing factor for atopic asthma in Iranian population, and CC genotype of this SNP can be associated with increased level of IgE in patients with asthma in the same population

    Nutritional knowledge, attitude and practice of Iranian households and primary health care staff: NUTRIKAP survey

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    The aim of this study is to determine knowledge, attitude and practice of Iranian households and health staff on nutrition at province level. The sampling method in NUTRIKAP survey for households in each province is singlestage cluster sampling and the size of clusters is equal. The sampling method for health staff in each province is stratified random sampling. Samples are selected from physicians, health experts, health technicians, nutritionists and health assistants (Behvarz). Overall, 14136 people in 57 clusters in each province and 480 health staff over the country participate in this survey. The necessary data will be gathered by the structured questionnaire and the interview with the eligible person in each household. Data gathering from health staff will be carried out by selfadministered questionnaire. The results of this study can help the bureau of community nutrition to provide the proper interventions to improve nutritional health of households

    Efficacy of biological agents and fillers seed coating in improving drought stress in anise

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    Many plants, including anise, have tiny, non-uniform seeds with low and light nutrient reserves. The seeds also show a weak establishment, especially under stressful conditions where their accurate planting in the soil and optimal yield are tough. This study sought to improve anise seeds' physical and physiological characteristics under drought stress. To this end, two factorial experiments under laboratory and greenhouse conditions were performed in a completely randomized design with 4 and 3 replications, respectively. Five levels of seed inoculation (inoculation with T36 and T43 of Trichoderma harzianum, and CHA0 and B52 of Pseudomonas fluorescent, and non-inoculation which means that control seeds were not treated with microbial inoculant), three levels of coating (K10P20, K10P10V5, and non-coating), and three levels of drought stress (0, -3, and -6 bars) were considered as the factorial experiment [vermiculite (V), kaolin (K), and perlite (P) numbers refer to the amount of material used in grams]. The laboratory experiment revealed that the combined treatments of bio-agents with coating increased the physical and germination characteristics of anise seeds compared to the control treatment. The greenhouse experiment showed that drought stress reduced the initial growth indices. Still, the combination treatments of biological agents and coating (fillers) could alleviate the destructive effects of drought stress to some extent and improve these indices. The best treatment was provided by T36 and K10P20 in both experiments, which significantly increased morphological indices.Peer reviewe

    Therapeutic Updates on Lichen planopilaris and Frontal Fibrosing Alopecia: A Systematic Review

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    Introduction: Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are skin diseases that affect the quality of life. Although a systematic review on LPP and FFA treatment was published in 2013, further updates are needed. The aim of this study is to review systematically the studies published after the last systematic review.Methods: We searched Scopus, PubMed, Embase, and ISI Web of Science. All the studies published during March 2012-June 2017 were included in this review. Two reviewers separately selected the studies and extracted the data. The results of studies were categorized as unimproved, stabilized, and improved based on the articles reports.Result: Among the 38 studies, 20, 17, and one studies assessed LPP, FFA, and both treatments, respectively. The papers were case reports, case series, cohorts, and randomized controlled trials. Antimalarial agents and pioglitazone resulted in enhancement in 73 and 71% of the LPP patients, respectively. Improvement and stabilization were observed in almost one third of the topical steroid users and 6/12 of Tacrolimus/Pimecrolimus users in LPP. Improvement and stabilization in FFA was found in 68% of the individuals using antimalarial agents, 83% of intralesional steroid users, all cases of finasteride users, and 95% of the people utilizing dutasteride.Conclusion: Contrary to the previous systematic review, we found antimalarial agents more effective than steroids in LPP. Finasteride/dutasteride may have favorable impacts on FFA. Intralesional steroids showed to be more effective than antimalarial agents in FFA. Still further studies are needed in order to define a treatment protocol. Low quality and heterogeneity of the articles were among the limitations for making a conclusion

    Environmental and ecological studies in northern Alborz aimed at developing the fisheries resources

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    Caspian Sea with an area of 400 thousand square kilometers is the largest lake in the world. The Caspian Sea about 1200 km from north to south on the longest section and an average width of 320 km. Along the coastline around the Caspian Sea is about 6500 kilometers. Caspian Sea is about 78,000 cubic kilometers of water volume that is 44% of stocks of blue lakes around the world. Caspian Sea basin, which is composed of seven major basins of the main watershed from west to east are: juniper, Talsh- Anzali, large Sefidrood between Haraz Sefid and, Hraz- Gharehsou, Nagorno Sv- Gorgan and Atrak in the basin of Aras no limits to the beach. Aras sub-basin is located in the North West and Iran, the second largest sub-basin of the Caspian Sea. Talysh-Anzali on the Caspian Sea basin West and the seventh largest sub-basin of the Caspian Sea. White basin is located in the South East of the Caspian Sea and the extent of the sub-basin of the Caspian Sea. Haraz located in the south Caspian Sea basin and the ninth largest sub-basin of the Caspian Sea. Gorgan is located in the South East of the Caspian Sea basin and the fourth largest sub-basin of the Caspian Sea. In these areas, about 28 percent of the total fish production in the northern waters of aquatic allocated
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