m. hasanzadeh

The design calculations of the spent fuel pool require the consideration of various parameters such as neutronic, thermal-hydraulic, safety, shielding, economic and operation. Considering the high cost of designing and building of a new spent fuel pool as well as the existence of empty spaces in the pool of some research reactors, neutronic and shielding calculations for the feasibility of using second pool of a typical research reactor as a spent fuel pool is done using ORIGEN2.1 and MCNP6 codes. The first step is the determination of the distance between fuels (grid pitch) in such a way that the effective multiplication factor for the worst possible case is less than 0.95, that 13 cm grid pitch fulfills this condition. Source term calculation for a fuel with the highest burnup (60%) is done as the most pessimistic condition. Continuous operation and 24 hours cooling are considered as the shortest possible time to transfer spent fuels to the storage rack in order to have the most pessimistic conditions in the design of spent fuel rack. For a rack with 100 spent fuels that is 87 cm away from the pool wall on each side, a 300 cm layer of water on top of the fuels and 85 cm thick concrete wall are enough for the possibility of using second pool as a spent fuel pool. It has been found that it meets the dose rate criteria of less than 1 and 10 μSv/h behind the wall and above the pool water level.

Thermal comfort is one of the important and effective parameters on the health and efficiency of the human body, and textiles play a significant role in providing this parameter. In this regard, many engineered textiles have been proposed by adjusting different thermal mechanisms. In the present study, the recent developments in the field of active and passive temperature control (heating, cooling and two-mode textiles) have been expressed with emphasis on the effective mechanism of heat transfer in the desired textile. Finally, the used methods are compared and the challenges and opportunities in this field are pointed out.

This paper aims to design a suitable irradiation box of topaz stones and improve the neutronic parameters by maintaining the necessary conditions for their cooling in Tehran Research Reactor (TRR). In this way, by defining an appropriate neutron filter and simulating the irradiation box in the TRR core with MCNPX2.7 code, the neutronic parameters of the core are calculated, and the best configuration is selected. Then, various components of the irradiation channel are simulated using the Solidworks software, and thermal calculations are performed using the Flow Simulation plug-in. The results showed that although the presence of water in the irradiation channel and topaz box results in good cooling for topaz stones, the slowdown of fast neutrons causes intense activation of the stones. However, by using a closed-loop independent of the reactor pool water and a gaseous fluid such as air, the thermal neutron flux and consequently the activity of the stones is reduced. Moreover, the results demonstrated that, in this case, acceptable conditions could be provided for long-term and safe irradiation of stones by selecting the appropriate fluid velocity and adjusting the core power.

The purpose of this paper is to investigate the possibility of using tubular fuel assemblies in Tehran Research Reactor (TRR) from the thermal hydraulic perspective. Tubular fuels have been used successfully in many Russian model research reactors in recent decades. The most important advantages of this fuel are higher neutron flux, more reactivity and less fuel loading compared to the current plate fuels. In this study, by selecting a tubular fuel assembly of IRT-4M type that is more geometrically compatible with the geometry and dimensions of the core grid plate, we modeled it using the Fluent software and also the RELAP5/Mod3.2 code. The thermal hydraulic parameters of this assembly have been calculated under the operating conditions of current MTR fuel. The results of the calculations showed that the maximum clad temperature in both calculation tools is sufficiently lower than 105°C, which indicates that without changing the current flow rate of the core, the heat produced in the tubular fuel can be well removed. Moreover, the maximum fuel temperature in tubular fuel is about 10°C lower than the maximum fuel temperature in the current standard fuel element, which is another advantage for this fuel type.

The purpose of this paper is to investigate the possibility of using fuel with annular geometry (Tubular) in Tehran research reactor (TRR) from a neutronic perspective. The use of annular fuels requires less fuel load due to higher flux generation and higher reactivity. It is noteworthy that one of the most important advantages of this type of fuel is the creation of an area in the center of the fuel complex for irradiation of materials and production of radiopharmaceuticals. Therefore, in the TRR, a new fuel with annular geometry has been adopted to replace the current fuel with cubic geometry. This fuel is similar to TRR fuel in terms of materials. For this purpose, the neutron conditions of the core are simulated using MCNPX2.7 and WIMS-CITATION codes. Then the obtained results from these codes were compared with the SAR results of the TRR. The obtained results in this paper show that to achieve the reactivity equivalent to the first core of the TRR, the critical mass of the tubular core fuel is up to 17% less than the critical mass of the first core fuel. On the other hand, using annular fuel, the neutron flux in the radiation channels increases up to about 14%. Also, according to the results of this study, the proposed tubular core, a core with an arrangement of 16 and at least 8 packages of 6 control rods are needed to achieve safety standards.

Severe hemorrhage is the leading cause of death in comilitary and civilian trauma. Approximately half of road crash fatalities occur due to severe hemorrhage before hospital arrival. In severe cases of bleeding, the use of agents that accelerate blood coagulation (hemostatic agents) is required. The aim of this study was to review on the hemostatic agents and products, from research to commercial stages, and categorizing them based on the physiology of hemostasis. Moreover, the applications and adverse effects of each category have been reviewed and compared; it can be an important step towards optimal clinical application of products and novel original reasearch design continuing the previous studies.

Literature search was conducted in scientific databases of PubMed, Scopus, Science Direct, SID, Magiran and IranMedex without filtering release date, by combining related keywords including hemostatic agents, bleeding, dressings and trauma. The abstracts were screened by two reaserchers independently to select the appropriate studies.

In this study, according to the basics of blood coagulation, the hemostatic agents and products were classified into five groups based on the mechanism of action including: (1) coagulants and procoagulants, (2) the concentrators of coagvlant factors, (3) mechanical cougulaton substrates, (4) physiologic coagulants and (5) chemical coagulants. The mechanism of action, applications, and side effects have been compared in each category.

Each hemostatic product can be more effective in special situations, in military and civilian trauma, due to their potency and mechanisms of action.

The fabrication of polypropylene composites using various types of reinforcements to improve the mechanical properties has received much attention in recent years. In this paper, enhancing the mechanical properties of polypropylene composites by adding different classes of natural and synthetic particle and fiber reinforcements were reviewed. Accordingly, it was found that the fabrication of polypropylene composites leads to an increase either in the strength of samples and corresponding mechanical properties. Moreover, surface modification and processing reinforcements, especially natural fibers via chemical and physical methods were studied. The results show an increase in the adhesion of reinforcements surface inside the polypropylene, which results in strength enhancement and improving the mechanical properties of polypropylene composites. The evidence from this study points towards the idea that the increased use of modified natural fibers in polylropylene composites and those natural or synthetic reinforcements which form hybrid composites provide promising research topics in the future.

Citrus, as a critical horticultural product, has a special place in our country's economy. Meanwhile, scale insects such as Planococcus citri and Pulvinaria aurantii are the most important pests of citrus in northern Iran and cause economic damage. To prevent the damage of these pests, various insecticides are recommended. Due to a waxy layer on their bodies, it is difficult to control them chemically. Excessive use of pesticides and repeated spraying can have adverse effects on non-target organisms. In the present study, the effect of three compounds was conducted on some biological and reproductive characteristics of a coccinellid predator, Cryptolaemus montrouzieri. Also, these compounds were grouped according to the criteria of the International Organization for Biological Control (IOBC).

The effect of three compounds at field recommended concentration and half dosage of them in 9 treatments, including: 1, 2: mineral oils, EC, at two concentrations of 5 ml/L and 10 ml/L, 3, 4: mineral oils mayonnaise, at two concentrations of 5 ml/L and 10 ml/L, 5, 6: insecticidal soap palizin 1.25 and 2.5 ml/L, 7, 8: buprofezin 0.25 and 0.5 ml/L and 9: water (control) were investigated on C. montrouzieri. Treatments were done on eggs via dipping method and on the fourth instar larvae and adults via direct spray on mealybug-infested citrus seedling after releasing the ladybeetle.

Mayonnaise oil (10 ml/L) caused a 43.4% reduction on egg hatching compared with that of control. Buprofezin treatment (0.5 ml/L) with 36.6, 35.5 and 40% mortalities on fourth instar larvae, male and female adult respectively, was significantly different compared to the control. In the treated females with buprofezin 0.5 ml/L, mean of longevity and fecundity were 30.9 days and 26.1 eggs compared to the control 87.8 days and 114 eggs, respectively. According to IOBC standard method, mayonnaise (5 ml/L) as harmless (E=24.6, class 1), buprofezin as moderately harmful (E=84.1, class 3), and other compounds as slightly harmful (class 2) were classified. Used compounds at half doses had a low adverse effect on tested parameters compared with field recommended concentration.

Many researchers emphasize the harmlessness of oils to pests' natural enemies. Also, the safety of palizin on them has been reported by some researchers. The use of buprofezin in the larval stage reduced the percentage of adult exit from the pupa, and in the maturing stage, reduced the number of ladybeetle eggs compared to other compounds, so its toxicity is observed to this predator. On the other hand, the effectiveness of mineral oils and palizin in reducing the population of citrus scales has been positively evaluated by researchers. Therefore, these compounds can be used as alternatives to chemical pesticides in the integrated management of citrus pest programs. Also, the mentioned compounds had a less adverse effect on the ladybeetle at the half dosage of the recommended concentrations, which can be used in combination with the ladybeetle to pest control.

The global financial crisis, started in 2008, has affected many economies and it has also caused a significant drop in global growth during past years. As time went on, various sectors has been affected due to decrease in demand and prices. Using CGE model, this paper investigates the effects of global agricultural price decrease on agricultural trade balance of Iran. The results showed that decrease in prices of agricultural goods has had a negative effect on trade balance of all agricultural products except three products, namely, wheat, industrial crops and wood products. In brief, the decline of global agricultural prices deteriorated the agricultural sector trade balance mainly due drop in export of horticultural products

The driver’s Sleepiness is an important risk factor for road accidents leading to death or disability. Little is known about sleep quality in Iranian drivers. This study was aimed to assess the sleep quality in those Iranian drivers recognized as responsible for a recent road accident in which at least one of the car occupants had been severely injured or killed.

In a cross-sectional study, 453 Iranian drivers were assessed within the first 24 hours after severe road accidents. After getting completed the informed consent forms and demographic questionnaires, we used Symptom Check List-90-Revised (SCL-90-R) and Pittsburg Sleep Quality Index (PSQI) for screening psychiatric problems and sleep quality impairments, respectively. Data was analyzed using descriptive statistical methods and multivariate linear regression analysis through SPSS-10 software.

Mean (±SD) nocturnal sleep duration of drivers was found to be 6.3±2.8 (median: 6). Based on PSQI, a total number of 263 drivers (73.5%) were poor sleepers. PSQI was correlated with a GSI more than 0.81 according to SCL-90-R, having used drugs which can affect the sleep, and a history of similar previous accident(s). Retired individuals had a better sleep quality.

Our study showed that sleep problems, especially early morning awakening, frequent need to lavatory during night, early insomnia and feeling too warm or cold, are common among Iranian drivers with severe road accidents.