Showing 5 results for Environmental Conditions
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Volume 10, Issue 4 (12-2010)
Abstract
Abstract- Considering the diverse climates of Iran, the need for architectural design according to climate zones is obvious. Especially in critical thermal conditions this need will be more important and becomes the architect’s most important challenge.
Cold climate is one of the important climates which deserve special design. In cold climate, summer is very short and environmental temperature is often below the comfort range, so the most important issue is heating. Since in most of the time we require to increase the temperature up to the comfort range.
This article aims to provide solutions for critical climate conditions. So Tabriz with a dry and cold climate was selected and its thermal analysis was done. Through this analysis we find out when there is heating problems and we can design solutions based on these findings. This information will help us to design the selected site conditions.
Behnam Karamloo, Mansour Khanaki, Mostafa Mafi, Seyed Abas Sadat Sakak,
Volume 16, Issue 10 (1-2017)
Abstract
In this study, the double stage mixed refrigerant LNG system is investigated, which is known for having the highest efficiency among the liquefaction cycles. The main purpose is to evaluate the performance double stage mixed refrigerant LNG system of point of view effect of variations the environmental and operating conditions of feed that has not been previously discussed. Such as variable environmental conditions during liquefaction processes, temperature, pressure and feed gas composition are. To view the response of the DMR liquefaction system to these changes, system which has been designed and implemented, was selected as the base case.The Results show that with decreasing temperature and increasing pressure feed natural gas, as an advantage, specific shaft work decreases and since in this case, minimum approach temperature in heat exchangers only slightly reduced than the allowed amount 3°C therefore with accepting a safety factor less (to insignificant amount) than the optimal case, can be used of this available advantage. Also, with increasing temperature and decreasing pressure of feed natural gas, while increasing the specific shaft work as well as temperature cross occurs in heat exchangers and means to from entering of the feed natural gas in the area prevented with special controls. Also, any changes in mole fraction of natural gas components make temperature cross in heat exchangers. And due to the change of the natural gas components mole percent, during the life of the well, should over time, the refrigerant composition in the cycle is optimized regarding to new conditions.
S.a. Azimi, V. Momeni, M.h. Alaei , A. Mirzaei, M. Rezvani Nasab, M. Ramezani Nezhad, A.h. Mohamadian,
Volume 20, Issue 3 (2-2020)
Abstract
In this research, the effect of adding clay Nanoparticles on increasing the lifetime of glass/epoxy composites under hydrothermal conditions has been investigated. For this purpose, samples containing 3 Vol.% of clay Nanoparticles and samples without clay Nanoparticles in resin epoxy has been manufactured for the fabrication of specimens of the tensile test using hand lay-up and vacuum bag. The specimens were placed under the hydrothermal condition of 90% humidity and 75 °C temperature for 500 hours in the incubator and were tested for tensile properties. The results show that addition of clay Nanoparticles decreases the strength of the composite by 21.39% in the newly produced samples while in a long time, these particles slow down the process of composite degradation, so that in the same environmental conditions, the strength of specimens containing clay Nanoparticles is 9% higher than the specimens without clay Nanoparticles.
Mohammad Saleh Barghi Jahromi, Vali Kalantar, Mehran Abdolrezaie,
Volume 20, Issue 7 (6-2020)
Abstract
In the current study, natural solar ventilation has been investigated aiming at reducing the consumption of fossil and thus, reducing greenhouse gas emissions in a hot and dry climate in which the behavior of various fluid variables (temperature, velocity, and flow rate) is considered in different conditions. Since solar radiation is not uniform throughout the day, passive solar ventilation is unstable. In this regard, the natural displacement flow in a solar ventilator with copper thermal absorber, double-glazed glass compartment to prevent thermal energy loss, as well as phase change materials for the storage of thermal energy has been investigated, experimentally. In the case of no phase change material, due to the creation of a suitable temperature difference, the panel has made the chimney effect possible for natural ventilation in some hours of the day, but in the early hours of the night, the temperature of the panel will be the same as the ambient temperature, and the chimney effect will not be available for proper ventilation. In a panel equipped with phase change materials, the system has acceptably been able to play an important role in reducing the temperature drop in the hours of the day with no solar radiation leading to a reliable air flow rate. In fact, the main purpose of using phase change materials in passive solar ventilation is the same effect, the use of excess energy in cases of energy shortages.
Volume 25, Issue 6 (11-2023)
Abstract
Among several pests infesting okra plants, the cotton mealybug, Phenacoccus solenopsis (Hemiptera: Pseudococcidae) is considered one of the most destructive pests. Field trials were conducted in a private field in Esna District, Luxor Governorate, Egypt, during two successive growing seasons (2021 and 2022) with the aim to study the seasonal fluctuation of P. solenopsis population infesting okra plants (Balady cultivar). Furthermore, the impacts of both climatic conditions and plant age on the seasonal variation of the tested insect pest were determined. The results indicated that P. solenopsis infested okra plants from the first week of March until the end of July, and had three peaks of activity per season, which were recorded in the first week of April, third week of May, and fourth week of June. The mean total population density of P. solenopsis per 10 leaves over the whole first season was 235.96±16.05 individuals and for the second season, it was 242.13±17.01 individuals. June was the most favourable month for P. solenopsis population increase (as measured during weekly inspections), while March was the least favorable in both growing seasons. Pooled effects of environmental conditions and plant ages had a strong relationship with P. solenopsis population density, with an Explained Variance (EV) of 93.26% in the first season and 95.09% in the second season, during the two seasons. Daily mean relative humidity was the most effective variable in explaining changes in the population density of P. solenopsis for the 1st season (2021), while the it was the major element influencing the changes in population in the 2nd season. On the other hand, the daily maximum temperature was clearly the least effective factor in population changes during both seasons. The data presented here can aid to monitor the oscillations in the population density of this pest.
