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Search Results: 1 - 10 of 642 matches for " Payam Najafi "
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Assessment of CropWat Model Accuracy for Estimating Potential Evapotranspiration in Arid and Semi-arid Region of Iran
Payam Najafi
Pakistan Journal of Biological Sciences , 2007,
Abstract: The aim of this research was estimating the accuracy of CropWat software to calculating potential evapotranspiration (ET0) in arid and semi-arid region of Iran. For this purpose, 9 locations of arid and semi-arid regions of Iran selected and the grass lysimeter data collected too. The lysimeter data are collected duration of May through November during 1988-1997. For the comparisons of the ET0 lysimeter data and ET0 resulted CropWat software in different point, three statistical parameters were used include Mean Absolute Relative Error (MARE), Root Mean Square Difference (RMSD) and correlation coefficient (R2). The results of this research show that the average of MARE, RMSD and R2 computed about 31%, 2.3 and 0.7, respectively in the study areas. In addition, the results of this research show that when the average of wind speed was less than 1 m sec-1 or wind speed was more than 1 m sec-1 with low ET0 lysimeter (ET0 less than 6 mm per day), CropWat has a low sensitive for estimating ET0 and it's necessary to improve the results for these areas. In concluded, the results of this research were showed that in these area because of intensive temperature and solar radiation, CropWat can not be estimated ET0 exactly.
Assessment of Change in Soil Water Content Properties Irrigated with Industrial Sugar Beet Wastewater
Sayyed Hassan Tabatabaei,Payam Najafi,Hussein Amini
Pakistan Journal of Biological Sciences , 2007,
Abstract: In this research the effect of industrial sugar beet wastewater has been assessed on the soil water content properties in summer 2005. The evaluated parameters were the soil water content points such as Saturation Percent (SP), Field Capacity (FC), Permanent Wilting Point (PWP), gravitational water and Total Available Water (TAW). The pilot design was fully randomized with three replications and three treatments. The three treatments were: 1-normal water, 2-industrial sugar beet wastewater (50%) and normal water (50%) and 3-sugar beet wastewater (100%). The experiments have been carried out in the field, in 21 columns with the diameter 110 mm and the height of 400 mm. The soil was irrigated using surface irrigation method for 12 events with a constant volume and period. Based on the result, the SP, FC and PWP initial value were 46.5, 35 and 15%, respectively for all the treatments. At the end of the period, the values changed to 47, 36.6 and 17.5% for T2. They are also increased significantly to 48.5, 37 and 18.7% for T3 at the end of the period. The increasing of soil Organic Matter (OM) during the period is expected to be the main factor for this change. The result shows that although the FC and PWP parameters are increased during the period but TAW decreased significantly from the 20 to 18.5%. The other effects of wastewater on soil and leached water quality should be evaluated too.
Assessment of Heavy Metal Pollution in Soils and Crops of Industrial Sites, Isfahan, Iran
Anahita Moradi,Naser Honarjoo,Jaber Fallahzade,Payam Najafi
Pakistan Journal of Biological Sciences , 2013,
Abstract: This study was planned to investigate the concentrations of heavy metal in soils and crops and estimate the potential health risks of metals to humans via consumption of crops grown at industrial sites (Zarrinshahr and Mobarakeh) and control site (Natanz) in Isfahan province, central Iran. The soils and food crops (wheat and rice grains and onion bulbs) were digested by acid digestion method and then were analyzed for Mn, Cu and Zn by atomic absorption spectrophotometer. The results showed that the concentration of Zn in the soils of Mobarakeh was higher than the soils of Zarrinshahr and Natanz. The concentrations of Mn in the soils of Natanz and Mobarakeh were higher than the soils of Zarrinshahr. The concentration of Zn in the wheat was significantly higher than that rice and onion crops. The concentrations of Zn and Cu were higher in wheat crop in Mobarakeh compared with other cases. Results of this study revealed that the concentrations of Zn, Cu and Mn in the soils of studied sites were below than the maximum allowable levels. The average concentration of Zn, Cu and Mn metals in rice, wheat and onion crops were below than the maximum allowable levels of WHO guideline. The estimated daily intakes of heavy metals from the crops of three sites were lower than the tolerable daily intake recommended by FAO/WHO. Consequently, these crops cannot be an important source of Zn, Cu and Mn for risk to human health.
Effect of Salt Levels and Cropping Methods on Wheat Agronomic Characteristics
Mahdi Khozaei,Ali Soleimani,Payam Najafi,Mohammad Feizi
Pakistan Journal of Biological Sciences , 2007,
Abstract: The purpose of this study was to evaluate the effect of Salt levels and Cropping methods on wheat agronomical characteristics. A Split plot layout within Randomized Complete Block Design with four replication was used. Irrigation water quality were in main plots, it consists in 4, 8 and 12 dS m-1 and Cropping methods were in sub plots that inclusive of traditional cropping, 60 cm furrow, 80 cm furrow and aside sloping 80 cm furrow with double row planting. The results shows the effect of salinity stress on 1000 grain weight, grain yield, sum of tiller, amount of germinated tiller, amount of kernel per spikelet and amounts of spikelet were measured decreased significantly. Effect of cropping methods on LAI, TDW and grain yield were more significantly. The greatest amount of LAI, TDW and grain yield were in 60 cm furrow where as, the lowest of LAI and grain yield were in a side sloping 80 cm furrow in case, the lowest of TDW obtained in traditional cropping method. Effect of cropping method on other measured factors were not significant. Interaction of salt treatments and cropping methods on LAI, TDW and grain yield were more significant where as, the highest amount of LAI, TDW and grain yield in 4 dS m-1 belong to traditional cropping method with exceptional of TDW that was in 60 cm furrow the traits declined significantly in a side sloping 80 cm furrow with the rising salinity stress in 12 dS m-1. According to this study the suitable method with the highest traits agronomy in low salinity (4 dS m-1) and high salinity (12 dS m-1) were traditional cropping method and 80 cm furrow method, respectively.
Effect of Cropping Methods and Salinity Stress on Wheat Agronomic Characteristics
Mahdi Khozaei,Ali Soleimani,Amir Hosein Shirani,Payam Najafi
Pakistan Journal of Biological Sciences , 2006,
Abstract: Water deficit associate with salinity in irrigation water is the major limiting factor in the Center and East of Iran region. Nevertheless, an experiment was conducted in 2005 at Esfahan National Salinity Research. The purpose of this study was to evaluate effect of cropping methods and salinity stress on wheat agronomic characteristics. A Split plot layout within Randomized Complete Block Design with four replication were used. Irrigation quality water irrigation were in main plot, it consists in 4, 8 and 12 dS m-1 and cropping methods were in sub plots that inclusive of traditional cropping, 60 cm furrow, 80 cm furrow and aside sloping 80 cm furrow with double row planting. The results showed effect of raising salinity stress on 1000 grain weight, protein yield, grain yield, biological yield, straw yield and harvest index were decreased significantly. Effect of cropping methods on protein yield, biological yield and straw yield were more significantly. While, the highest amount of the traits agronomic were in 60 cm furrow cropping method, whereas the lowest the agronomic characteristics were in traditional cropping method with the exception of protein yield that lowest was in aside slopping 80 cm furrow. The effect of cropping methods on 1000 grain weight and harvest index were not significantly. According this study the suitable method with the highest traits agronomy in salinity stress was 80 cm method. While, the traditional cropping method did not recommended in high salinity stress condition.
An Inquiry into Cultural Continuity and Change in Housing: An Iranian Perspective  [PDF]
Rafooneh Mokhtarshahi Sani, Payam Mahasti
Sociology Mind (SM) , 2013, DOI: 10.4236/sm.2013.33031

The arrival of modernization has had an adverse effect on current Iranian housing architecture; as such, that it is now finds itself in a difficult predicament. Therefore, various national architectural conferences, in addition to individual investigations, have been focused on the renewal of Iranian housing architecture over recent decades. Whilst these examples have not culminated or resulted in defining a clear Iranian trend and style in housing with recognizable characteristics, it would be useful to explore some of the more successful examples in order to obtain an overview of what has been done in Iran in this respect during recent years. Accordingly, the study has focused on identifying the architectural characteristics of Iranian houses, which have been modified and used in the present designs. In this study, through a comparative typological analysis of the different traditional Iranian housing types, their main characteristics have been categorized. The categorization later applied for the analysis of the contemporary houses designs. The results of this investigation have shown that, in contemporary samples, although the idea of Iranian traditional houses has remained; the concept of traditional houses has been altered and changed.

The Realm of Management in Radiology: What Are the Borders?
Payam Tarighi
Iranian Journal of Radiology , 2010,
Abstract: If we carefully think about "management", there is little space in our life far from its influence. We feel the presence of management in every decision, from the most personalized matters to world-wide issues. In an interesting general model, there are four categories for management levels: managing yourself, managing people, managing the organization and finally, managing the society. So we need management as a scientific key for dealing with challenges in every category Challenges facing the medical imaging industry are numerous, such as handling daily changing technologies, managing resources (human and financial) for providing high competitive cost-effective consumer-satisfying services, quality improvement and many other obstacles. How can we be sure about the best practice, medical safety, correct investments, cost-saving and other similar topics in our settings? Questions like these can not be answered truly unless we believe management as an inseparable part of our practice which needs to be handled by professionals whether as consultants or as leaders. This presentation focuses on defining the realm of management in radiology from the health administration specialist point of view.
Experimental Validation and Simulation of Fourier and Non-Fourier Heat Transfer Equation during Laser Nano-Phototherapy of Lung Cancer Cells: An in Vitro Assay  [PDF]
Mohammad E. Khosroshahi, Lida Ghazanfari, Payam Khoshkenar
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.518208
Abstract: This paper investigated the numerical scheme extended to solve the hyperbolic non-Fourier form of bioheat transfer equation and the experimental trials were conducted to validate the numerical simulation. MNPs were prepared via co-precipitation and modified with a silica layer. The amino modified Fe3O4/SiO2 nanoshells were covered with gold colloids producing nanoshells of Fe3O4/SiO2/Au (MNSs). In vitro assays were performed to determine the effect of apoptosis of QU-DB lung cancer cells based on the cells morphology changes. Cell damage was reduced by decreasing the power density of laser. Also, a larger area of damage on cell culture plates was observed at longer intervals of laser irradiation. The effect of nanoshell concentration and irradiation rate has been evaluated. A maximum temperature rise of 6°C was achieved at 184 W/cm2 and concentration of 0.01 mg/ml. The experiment confirmed a hyperbolic behaviour of thermal propagation. The results revealed that the three-dimensional implementation of bioheat equation is likely to be more accurate than the two-dimensional study.
On the ErdÖs Distance Conjecture in Geometry  [PDF]
Amir Jafari, Amin Najafi Amin
Open Journal of Discrete Mathematics (OJDM) , 2016, DOI: 10.4236/ojdm.2016.63012
Abstract: ErdÖs asks if it is possible to have n points in general position in the plane (no three on a line or four on a circle) such that for every i (1≤i≤n-1 ) there is a distance determined by the points that occur exactly i times. So far some examples have been discovered for 2≤n≤8 [1] [2]. A solution for the 8 point is provided by I. Palasti [3]. Here two other possible solutions for the 8 point case as well as all possible answers to 4 - 7 point cases are provided and finally a brief discussion on the generalization of the problem to higher dimensions is given.
Analysis of V Transmission Lines Response to External Electromagnetic Fields
Ahmad Cheldavi;Payam Nayeri
PIER , 2007, DOI: 10.2528/PIER06093003
Abstract: In the present paper the response of V transmission line to electromagnetic illumination has been obtained. Also in order to determine the VTL frequency operation band for both TE and TM modes a Gaussian pulse source has been applied to the structure. The VTL structure has received considerable attention in high frequency and microwave IC packaging. The purpose of this study is to determine high frequency design considerations in order to reduce the effects of electromagnetic interference (EMI) on the VTL structure and maintain the desired performance. It was observed that the effect of incident EM waves on the V lines performance is considerably lower than conventional microstrips, however the V lines are more sensitive to sources at close proximity. In addition, although the V lines show lower dispersion at higher frequencies, their frequency operation band is limited by a resonance like behavior which is directly related to the V groove dimensions. The full wave analysis is carried out using the Yee-cell based 2 Dimensional Finite Difference Time Domain method (2D-FDTD), while enforcing a very stable and efficient mesh truncation technique.
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