In this paper theoretical and experimental investigation of a right hand circularly polarized microstrip rectangular patch antenna have been presented. The antenna has a coaxial feed and designed for operating at L1 frequency (1575 MHz) of global positioning systems (GPS). The antenna have been simulated and optimized using the HP-HFSS software in combination with Empipe3D. The inherently narrow bandwidth of the antenna was increased to 70 MHz using an air layer. A useful practical method was proposed in order to minimizing the input VSWR of the antenna. Theoretical and measured results have been presented and compared.

This study aimed to investigate the effect of irrigation regimes on grain yield and physiological indices of aerobic rice genotypes in Khuzestan province for two years (2014 and 2015). Four irrigation regimes (1, 3, 5 and 7 days) in main plots and 12 rice genotypes in sub-plots with three replications were considered. The combined analysis results showed that there were significant differences between genotypes, irrigation regimes and their interaction at all growth stages at 1%. SWR also increased with growth, but 100 days after planting due to the effective role of stem particularly in terms of reducing the amount of water, a decline was seen in this trait. By decreasing the irrigation regime due to less canopy shading, the NAR slowed down. The highest LWR were observed under 5-and 7-day in irrigation regimes, but SLW decreased in these irrigation regimes. The mechanism of escape from stressful conditions reduced the growth period by decreasing the irrigation regime. Finally, it is recommended that this experiment be carried out in irrigation regimes and other genotypes.

Increasing the concentration of heavy metals in soil has adverse effects on ecosystem and causes serious damage to humans. Quantifying pollution can be helpful for soil management. In this study, the pollution of heavy metals has been studied and quantified in agricultural lands around some industrial units at Ardabil plain. For this, we selected 9 industrial units and prepared 46 soil samples (0 to 30 cm). Clay, sand and silt percentages, soil organic carbon content, pH and EC were measured. The heavy metals were extracted by digestion using HNO3 and HCl and the concentration of Pb, Zn, Cu and Cd were measured by AAS. Pollution index (Pi), comprehensive pollution index (Pj), ecological risk (Er) and potential ecological risk (RI) were calculated. The average concentration of heavy metals varied from 0.724 mgkg-1 of Cd to 120.58 mg/kg-1 of Cu. All regions had Pi greater than 2 and showed mild pollution except region 4 which had slight pollution. The pollution index of Cd had the highest value among all heavy metals. Pj had the lowest (1.268) and highest (3.636) mean values in regions 2 and 5, respectively. Region 2 had slight pollution class, regions 1, 6 and 7 had a mild class and regions 3, 4, 5, 8 and 9 had a moderate class. The ecological risk of Pb, Zn and Cu was lower than 3.0 in all regions and ErCd was between 120 and 240 for regions 3, 5, 8 and 9 increasing a serious pollution class and greater than 240 indicating a severe pollution class for other areas. All regions were in the serious pollution class according to the RI index. There is a significant difference between the concentration of Pb (sig. 5%) and Zn and Cu (sig.1%) in all regions. It shows differences between regions cannot be related to parent material and human activities have resulted in an increase in metal concentration.

One of the most important aspects of software project management is the estimation of cost and time required for running information system. Therefore, software managers try to carry estimation based on behavior, properties, and project restrictions. Software cost estimation refers to the process of development requirement prediction of software system. Various kinds of effort estimation patterns have been presented in recent years, which are focused on intelligent techniques. This study made use of clustering approach for estimating required effort in software projects. The effort estimation is carried out through SWR (Step Wise Regression) and MLR (Multiple Linear Regressions) regression models as well as CART (Classification And Regression Tree) method. The performance of these methods is experimentally evaluated using real software projects. Moreover, clustering of projects is applied to the estimation process. As indicated by the results of this study, the combination of clustering method and algorithmic estimation techniques can improve the accuracy of estimates.

Soil water repellency (SWR) is a widespread natural phenomenon that results from a complex interplay between the hydrosphere, lithosphere, biosphere, atmosphere, and anthroposphere. Sewage sludge application can induce soil water repellency (SWR), impacting soil hydraulic properties. This research examined the effect of soil microbial manipulation (removal and addition) on SWR and water retention in a silty-clay-loam soil amended with varying sludge amounts. Three levels of water repellency (zero, weak and strong) were artificially created in a silty clay loam soil by adding urban sewage sludge. The results showed that the elimination of soil microorganisms such as fungi and bacteria and their interactions significantly (P≤0.01) affect the hydrophobicity, soil water retention curve (both wetting and drying) of the sludge-treated soils. Microbial exclusion significantly reduced SWR (21-49%), suggesting that microbial activity contributes to the formation of hydrophobic compounds. Conversely, microbial inoculation increased SWR (27.5-50%), indicating microbial production or transformation of hydrophobic substances.  It is concluded that soil microorganisms can increase soil water repellency. Also, soil microorganisms can affect the soil water retention curve through their influence on soil water holding capacity, depending on microbial diversity. These findings highlight the critical influence of microbial activity on SWR and water holding capacity in sludge-treated soils.

Water deficit in arid and semi-arid regions is the major yield-limiting factor of crop plants in arid and semi-arid regions. So, prevention of water loss is the first major step to obtain proper crop yield in rainfed lands of these regions. This study was conducted to investigate the effect of mulch application on soil water retention under rainfed conditions in a semi-arid region. Toward this, five wheat straw mulch levels (0, 25%, 50%, 75%, and 100% of land surface cover) were used according to the randomized complete block design at three replications in a rainfed land with 10% steepness in Zanjan. About 6 ton straw mulch was used in 100% treatment. Fifteen plots with 2m×5m in dimensions were installed in the land and S was measured using the volumetric method in each mulched plot at 7-day interval during wheat growth period (from October 2015 to July 2016). Results indicated that SWR temporally varied during the growth period, so that the highest value of SWR in the mulched plots was observed in March, when the heavy rainfalls were occurred in the area. SWR was significantly related to straw mulch level (R2= 0. 95, p< 0. 001). Increasing SWR in the mulched plots was attributed with increasing soil water holding capacity. Application of straw mulch positively affected on the soil water holding capacity. The highest SWR was observed in 100% mulch (10. 62%), about 11% more than that one in the contour plot. There was no significant difference between 75% mulch and 100% mulch in SWR as well as soil water holding capacity, so the application of 75% straw mulch can be considered as the optimum level for increasing soil water holding capacity as well as SWR in the rainfed lands of semi-arid regions.

Background and Objectives: Soil Water Repellency (SWR) is one of the dynamic soil characteristics that either reduce water penetration in the soil or prevent it. In the northern forest areas of Iran, fire is one of the most important environmental concerns and is one of the main causes of the change in soil water repellency phenomenon. Therefore, this study aims to investigate prescribed fire effect on the soil of forest areas of Toshen's watershed, temporal variability and its interaction with physical and chemical properties of soil in Golestan Province. Materials and Methods: Soil of forest areas in the slope class of 15-30% and depth of 0-5 cm of soil surface was studied in 30 replications in laboratory. Physical and chemical properties of soil, including percent of clay, silt and sand, soil organic matter, pH, EC and aggregate stability (MWD) were investigated before and after fire. In order to study the effects of fire on soil water repellency in laboratory conditions, prescribed fire was applied. SWR was determined with Water Drop Penetration Time and Molarity of an Ethanol Droplet tests, before and after fire. Results: According to the WDPT test, before the fire, 100% of plots were wettable (class 1), but one day after the fire, 100% of the plots were showed slightly water repellent (class 2 and 3). The MED test showed that all plots were wettable (class 0) before the fire. One day after the fire, the intensity of SWR increased, so that 30, 50 and 20% of the plots were slightly water repellent (class 1), moderately water repellent (class 2) and less strongly water repellent (class 3), respectively. Investigating the process of temporal variability of both SWR indices showed that the SWR class after the fire is temporary and up to one month after that, the SWR classes is greatly reduced. The results showed that there are good correlations between two post-fire hydrophobic tests. (R2=0. 85). There was a moderate correlation between two WDPT and MED SWR tests with pH, EC, MWD and soil organic matter, but as for soil texture components, there was poor correlation. Relatively poor SWR correlations with soil physical and chemical characteristics indicate that these changes are not likely to be the main cause of SWR changes. Some of these changes can be explained by the variability of aggregate stability after the fire. These changes in the mechanical stability of the soil structure can be caused by two main mechanisms: (1) Changes in the composition of the solid components in the soil that increase the cohesion forces between the particles in the aggregates. Consequently, the stability of the soil structure against the physically destructive forces increases. (2) Changes in the physicochemical properties of the soil solution (an increase in the EC) that prevent clay dispersion and microaggregate destruction (physicochemical mechanism). Conclusion: Finally, the results of this study showed that despite the high wettability in loess soils, fire can be an external factor that causes a weak and immediate increase in SWR. The slightly soil water repellent may be due to the following: (i) SWR often occur in coarse soils with high organic matter. (ii) The samples were taken from the soil surface layer (0-5 cm), while the fire can cause some organic matter to accumulate in the subsurface layers and cause SWR on lower horizons.

Ensemble modelling is expanding in several areas of engineering, especially different aspects of water engineering. Accurate estimation of saffron water requirement (SWR), an essential strategic production of the agriculture sector, is a crucial and influencing act in local water planning of this region. Hence, this study aimed to check the applicability of ensemble modelling in enhancing SWR at Birjand, Southern Khorasan, Iran. The actual water requirement of saffron was recorded in the field lysimetric laboratory at the University of Birjand. The simulation of water requirement was conducted utilizing Decision Tree Regression (DTR) with input climate features. Additionally, Boosting and Bagging methods were employed to establish and enhance the ensemble process of soil water requirement (SWR) simulations. To track the effectiveness of any method, some comparative tests were designed, such as statistical criteria (RMSE and MAE) detection, Violin plot analysis, over/underestimation, times series comparison, and error improvement test. Results indicated that although the acceptable performance of DTR in simulating SWR, the probable improvement was potentially felt. Derived results confirmed that supervised ensemble modelling (Boosting) could enhance the accuracy of DTR by more than 30 percent (reducing absolute error from 36 mm to 23.65 mm), resulting in declining RMSE from 0.44 mm to 0.07 mm. Further, different experiment outcomes revealed that the Boosting algorithm quality is more appealing than DTR and Bagging outputs.

A low-cost and portable vector network analyzer (VNA) which covered operating frequency between 1MHz to 3GHz is used for vector reflection coefficient and standing wave ratio (SWR) of the various microst rip antennas. This paper presents measurements of various ult ra wideband (uwb) microstrip antennas for applications in biomedical field. Select ion of antenna is an important key for detection of different situations in biological signals. Measurements of antennas were performed by using miniVNA Tiny which operates by radiat ing an electromagnetic wave through an antenna and measuring standing wave rat io (SWR) and return loss. However, the miniVNA Tiny is low-cost components and easy-toproduce antennas. The results indicate the good performance for UWB systems, especially microwave medical imaging applications. However, this device may enable for a low cost stepped-frequency system for use in t issue spect roscopy, field monitoring, and potent ially in breast tumor detect ion.