Emitters clogging is one of the most important problems in the operation of drip irrigation systems and also it is one of the main obstacles to the development of this irrigation method. To investigate the effect of discharge, Operating Pressure and management of irrigation system on clogging, emitters with discharges of 4 and 8 l/h, under three different Operating Pressures (1. 0, 2. 0 and 3. 0 bar) and under three irrigation management methods (four, two and one times flow cutoff in every four hours operation) were tested for 132 hours. Accordingly the research included 18 treatments with four replicates which lasted for four months from July to October. In order to monitor the clogging in a limited time, 0. 5 g/l of chalk was added to the water reservoir of the system. After 12, 36, 84 and 132 hours of the system operation, the clogging percentage of 4 l/h-emitter was 1. 49, 1. 12, 1. 14, and 1. 07 times more than the clogging percentage of 8 l/h-emitter. Discharge reduction in emitters under higher Operating Pressure was less than that in emitters under lower Operating Pressures. After 132 hours of system operation, the clogging percentages in emitters under Operating Pressures of 1. 0, 2. 0 and 3. 0 bar were 91, 86 and 17, respectively. The effect of irrigation management method in treatments under operation Pressure of 1. 0 and 2. 0 bar did not show a clear trend. Although, there was no meaningful difference between experimental treatments in emitters under 3. 0 bar Operating Pressure, but in those with less flow interruption per the same Operating time, less clogging was observed.

This study was designed and carried out to determine the effects of Operating Pressure and irrigation water salinity on the performance of common Pressure- compensating emitters in irrigation systems. The study evaluated three commercial brands, namely, “Netafim”, “Eurodrip,” and “Peresi Zalvan”. These emitters were tested at flow rates of 8 and 24 L/h under Operating Pressures of 0.5, 1.5, and 2.5 bars. Additionally, two levels of water salinity (5 and 12 dS/m) were considered. The results revealed that increasing Operating Pressure from 0.5 to 2.5 bars and raising salinity from 5 to 12 dS/m led to either increased or unchanged coefficient of discharge variations in different emitters. Comparing pre-test (new) emitters with post-test (used) ones showed variations due to various factors, including Pressure changes, salinity effects, and inherent emitter characteristics. Notably, the impact of salinity did not result in significant differences in emitter performance under varying Pressure conditions. However, for the Netafim and Eurodrip emitters (8 L/hr), averaging the results across all three Operating Pressures indicated that increased salinity led to reduced discharge. Specifically, the reduction was approximately 3.8% for Netafim and 2.6% for Eurodrip. Also, it was concluded that the application of 2.5 bar Pressure led to the entry of parts and solid objects in the irrigation pipes or passed through the filtration system into the emitters, resulting in a decrease in flow rate. However, this problem can be solved to a large extent by washing the pipes before starting the system. Netafim emitters (8 L/hr), despite the lack of significant entry of these objects, had a diaphragm adhesion problem, and showed the greatest decrease in flow rate due to this reason. A detailed examination of the destroyed samples showed that the reason for these differences was the different shape and structure of the water inlet. Accordingly, the smallness of the cross-sectional area of water inlet, reduces the entry of solid parts. Therefore, application of 2.5 bar Pressure resulted in the highest rate of solid parts entry into the Peresi Zalvan with the largest cross-sectional area and the lowest rate of entry in the Netafim (8 L/hr). However, this problem can be solved to a large extent by washing the pipes before starting the system.

When a natural gas pipeline ruptures, the adjacent upstream and downstream automatic control valves (ACV) should close quickly to prevent leakage or explosion. The differential Pressure set point (DPS) at each valve location is the main criteria for value setting in ACV actions. If the DPS is not properly adjusted, the ACV may mistakenly close or it may not take any actions at a proper time. In this study, the effect of characteristic parameters such as pipeline operational Pressure (POP) and pipeline Pressure drop rate (ROD) due to rupture or a major leak was experimentally investigated on DPS. 25 different conditions with the double set of the mentioned typical characteristic parameters were chosen. In each condition, the differential Pressure (DP) was measured over a period of 180 s by statistically analyzing the experimental results, so 25 maximum DP values (DPSs) were obtained. The DPS rises by an increase in ROD or a decrease in POP. Because of using nitrogen gas instead of natural gas for safety reasons and the uncertainties, the DPS results can be practically applied by adding a safety factor of 15%. Finally, the diagram of DPS with respect to ROD and that of non-dimensional DPS (DOP) versus non-dimensional ROD (RTP) were provided for different POP’ s.

Chemical Vapor Deposition (CVD) is one of the most popular methods for producing Carbon Nanotubes (CNTs). The growth rate of CNTs based on CVD technique is investigated by using a numerical model based on finite volume method. Inlet gas mixture, including xylene as carbon source and mixture of argon and hydrogen as carrier gas enters into a horizontal CVD reactor at atmospheric Pressure. In this article the Operating Pressure variations are studied as the effective parameter on CNT growth rate and length uniformity.

Nowadays using 3D printing for prototyping is well known in industrial applications and there are efforts to make functional parts with this technology to reach low volume production markets. By using pellets rather than filaments, the limitations caused by lack of variety of materials can be conquered. Also there will be no need to make a massive part as several divided parts and then glue them together. In this article pellets of ABS, that are well known and functional in industry, are analysed for an extruder to investigate the ability of pellet material extruding. Characteristic specifications of extruder such as Operating Pressure, screw rotational speed and required torque for rotating the screw are achieved for they are important factors to find out the mechanism for experimental tests and selecting suitable Operating parts such as motor and gearbox. At the end, the experimental tests on designed system are done and the result approved the trends of theoretical data.

Background: The current study is to evaluate cardiovascular effects of anesthetic medications and volatile anesthetics on cardiac stress using cardiac stress index (CSI) and rate Pressure product (RPP) and to determine which of them in useful in evaluating cardiac stress after comparing results obtained from each method.Materials and methods: 40 patients, 60-80 years old, who were all performed trans abdominal prostatectomy were studied. Patients were divided into two groups, half of patients were placed in group A and the other half in group B. The study was carried out as a blinded study. CSI was measured and evaluated in group A and RPP changes were studied in group B.Results: The mean CSI were 60.25±5.57, 63.05±5.54, 55.75±4.78 and 67.65±4.88 before anesthesia induction, after induction, before surgical incision and in recovery respectively. There was no meaningful difference.RPP mean in four above mentioned stages was 10.15±0.44, 9.9±0.69, 6.8±0.36 and 9.2±0.61 respectively. There was a meaningful difference between RPP in stages before anesthesia induction and before surgical incision (P<0.0001).Conclusion: Considering the obtained results from this study, it can be seen that even in noncardiac surgery, the stress level is high in patients in the stage before surgery. This figure was not clear in RPP index case and was not in accordance with CSI, which means CSI has been able to illustrate existing stress level better and efficiently.

Background: Obesity is one of the most crucial risk factors in the occurrence of non-communicable diseases. Its prevalence has increased even among health care personnel and could render them susceptible to a myriad of diseases, particularly cardiovascular disorders (CVDs). Diverse treatment methods have been devised in this regard, one of which is the consumption of green tea. Owing to this, the present study attempted to explore the effect green tea exerts on the body mass index (BMI), blood Pressure, and pulse rate of Operating room personnel.Methods: The current before-and-after clinical trial was conducted on 24 Operating room personnel at the Shahid Motahari Hospital in Isfahan, Iran, in 2015. After informed consent forms were obtained from the subjects, they were asked to consume 4 cups of green tea, containing 3 g of green tea leaves in 300 ml of boiled water at 80oC, daily for 8 weeks. Their BMI, blood Pressure, and pulse rate were monitored before and after the consumption of green tea. Data analysis was carried out in SPSS software.Findings: The results of the study demonstrated that systolic Pressure and pulse rate had a considerable decrease after 8 weeks of consumption of green tea. Nevertheless, no effect was observed on BMI and diastolic Pressure.Conclusion: The consumption of green tea can cause a beneficial reduction in systolic blood Pressure and pulse rate, and thus, improve the cardiovascular status.

Background and purpose: Pre-eclampcia is one of the most important factors of mortality and morbidity in mother, fetus and neonate. The exact causative factors are yet unclear. Early diagnosis of preeclampsia remains one of the most important function of antenatal care. The aim of this study was to determine the value of MAP at 13-26 weeks of gestation in predicting the subsequent development of preeclampsia.Materials and methods: In a prospective and longitudinal study, 240 pregnant women seen at the health care centers for prenatal care were registered in the study by random selection, from Oct 2000 to Sep 2003 in Babol, Mazandaran. In this research MAP was measured twice at 13 to 26 weeks of gestation but at 28 weeks until delivery time blood Pressure and proteinuria was determined three times. Women were followed up to check the occurance of pre-eclampcia 24 hours after delivery. Women who had history of any disease and taking medicine were excluded from this study.Results: A significant relationship between the mean MAP (>90 and>85) and incidence of pre-eclampcia was found in this study (p<0.001). For MAP>85, negative and positive prediction values were %96.2, and %41.4, respectively, the sensitivity and specificity were %66.7 and %89.9. For MAP>90, negative and positive prediction values were %95.3, and %58.5, the sensitivity and specificity were %55 and %95.9.Conclusion: MAP>85 or 90 in midtrimester maybe a useful predictor of preeclampsia in 41.4% and 58.5% (respectively). More research is needed to establish an ideal predictive test for preeclampsia that allows its prevention or management.