s.m. abtahi

Soil frost heaving causes significant destruction to road pavements, railways, pipelines, and other lifeline infrastructures. The conventional methods for dealing with the soil frost heave are primarily based on using the materials whose production and use are harmful to the environment. Due to the recent ecological concerns, developing novel alternative methods has received much attention. This study aims to investigate the possibility of using the microbially induced calcite precipitation method to control soil frost heave for less pollution introduction to the soil. In this study, the Sporosarcina Pasteurii bacterium was used for calcite precipitation. The influence of three factors in four levels, including bacteria concentration, cementing solution concentration, and curing time, was investigated based on a plan set by Taguchi design of experiment method. The results were obtained by analysis of means and analysis of variance statistical methods and compared with the conventional frost heave reduction methods. The results were presented in terms of heave ratio. Based on the testing results, the heave ratios (frost heave ratios of the treated to untreated samples) were obtained to be in the range of 0.21 to 0.42. The results showed that bacteria concentration was the most influential factor in the total frost heave of the treated soil. The influence of curing time was in second place, and the effect of cementing solution concentration was relatively less. The minimum frost heave was achieved in 108 colony-forming units per milliliter bacteria concentration, 0.6 mole per litre cementing solution concentration, and 21 days of curing. The findings indicated that the used method could be efficiently used to reach the desired objective. The heave ratios obtained by this method were promising to a great extent compared to the conventional methods. The reduction of frost heave due to the application of this method was attributed to the precipitated calcite within the soil voids and was justified by the scanning electron microscopy images of the treated soil samples. This study proved that the proposed method might be utilized as a potential ecological-friendly approach in the future researches.

Some organizations due to the challenges of the present age and the impact of Research and Development projects on the continuity of them, invest in these projects. The purpose of this study is selecting the optimal portfolio of agricultural Research and Development projects in Fars Agricultural and Natural Resources Research and Education Center. The research is applicable from the purpose aspect and is descriptive-survey method based on essence. By studying the literature and interviewing with experts, project evaluation attributes were identified and 16 projects were evaluated by experts. The attributes weight was calculated by the grey Shannon entropy method that "time risk", "technical backup existence" and "risk execution" are the most important attributes. Then projects were prioritized with the grey theory approach. In order to validate the model results, the projects were evaluated with COPRAS-G method which was seen by comparing results, the rank of projects is not identical in all cases. Therefore, by using the Copeland method, the ranks were combined and the final rank of each project was calculated. According to the results, the total budget was allocated to higher priority projects and the optimal project portfolio was determined. The results of this study can be used to prioritize the projects and to form optimal portfolio in project-oriented organizations such as scientific and research centers.

In order to study of effects of nitrogen fertilizer and seed inoculation with plant growth promoting rhizobacteria (PGPR) on yield، fertilizer use efficiency، rate and effective grain filling period of soybean (Glycine max L.)، a factorial experiment was conducted based on randomized complete block design with three replications in 25 km Gorgan at Golestan province in 2011. Factors were different rates of nitrogen fertilizer in four levels (without nitrogen and application 25، 50 and 75 kg urea/ha) and seed inoculation with plant growth promoting rhizobacteria in five levels (without inoculation، seed inoculation with Pseudomonas putida strain 41، Pseudomonas putida strain 186، Azotobacter chroococoum strain 5 and Bradyrhizobium japonicum). The results showed that nitrogen fertilizer rates and seed inoculation with PGPR had significantly effects on grain yield، grain 100 weight، number of seeds per plant، plant height and all of grain filling parameters. Maximum of grain yield and grain filling period were obtained in application of 75 kg urea/ha × seed inoculation with Bradyrhizobium japonicum. Seed inoculation with plant growth promoting rhizobacteria and Bradyrhizobium japonicum increased nitrogen use efficiency compared to no seed inoculation. Of course، the highest nitrogen use efficiency belonged to seed inoculation with Brady rhizobium japonicum. Means comparison showed that maximum of nitrogen use efficiency was obtained in application of 25 kg urea/ha×seed inoculation with Bradyrhizobium japonicum and minimum of it was obtained in application of 75 kg urea /ha × no seed inoculation. It seems that in order to increasing of grain yield and the other traits (except nitrogen use efficiency) can be suggested that be applied seed inoculation with Bradyrhizobium japonicum × application of 75 kg urea /ha in second cropping of soybean.

This study was designed to optimize the use of organic and chemical fertilizer combinations in the production of red pepper to reduce costs and avoid environmental pollution. Therefore, the effect of 12 different treatments of animal and chemical fertilizers was studied in a randomized complete block design on yield and active ingredient (Capsaicin) red pepper. Variance analysis of the data indicated significant differences at 1% level among the different treatments. Mean comparisons with Duncan's test at 1%, revealed that the maximum yields with averages of 7.6, 7.3 and 7.2 ton.ha-1 were obtained in the treatment numbers of 10 (Organic, nitrogen, phosphorus and potassium, respectively. 20 ton.ha-1, 60, 50 and 50 kg.ha-1), 12 (Organic, nitrogen, phosphorus and potassium, respectively, 40 ton.ha-1, 20, 16 and 16 kg.ha-1), and 8 (40 ton.ha-1 of organic fertilizer) respectively. Variance analysis of active ingredient percentage showed significant differences at the 5% level. Highest active ingredient with average 0.1747% was obtained in treatment of number 3 (nitrogen, phosphorus and potassium, respectively 150, 100 and 100 kg.ha-1). In general it can be concluded that yield could be increased by using a proper combination of organic and chemical fertilizers.

Polymer application for the improvement and modification of the bitumen used in roads surfaces has expanded in recent decades. The roads engineers and constructors, therefore, have used the modified bitumen in asphalts helping in this way to increase roads and pavements service life and improving the durability of the roads and asphalts. The bitumen used in asphalt mixture constitutes only a low percentage of the weight of this mixture (between 4% and 6%), but even this small amount has a significant effect on asphalt performance. The polymers that are mostly used in promoting the bitumen specifications are polymer modifiers including: styrenebutadiene- styrene (SBS), as well as similar polymers such as styrene-butadiene-rubber (SBR), ethylene-vinylacetate (EVA) and polyethylene (PE). Polymers as the most important family of bitumen modifiers are added to bitumen to improve bitumen performance and to increase its effectiveness. Among the existing polymers, SBS is considered as the best bitumen modifier. In this research, SBS as one of the elastomer-thermoplast modifiers was added in different weights (2%-5%) to bitumen 60/70 in Isfahan Refinery and its effect on asphalt properties were investigated. Adding this polymer to bitumen improves the Marshall stability of sample asphalt, flow, module of rupture and asphalt content voids. However, it has a minor effect on asphalt special weight. Adding SBS would also lead to asphalt fatigue life.

With respect to the physical and mechanical limited qualities of bitumen, it benefits from certain specificability in application and its life service. Polymers as the most important modifiers of bitumen are applied to it in order to improve its functional efficiency. Among various polymers, styrene-butadiene- styrene (SBS) is the best modifier of the bitumen. In this work, SBS polymer as one of the modifiers of elastomeric thermoplastics with different weight percentages (2% to 5%) have been mixed with bitumen (60/70) of Isfahan Refinary and its effect on different properties of the bitumen for example penetration index, softening point, Frass breaking point and reduction in weight perecentage has been studied. Furthermore, in this paper, the modified bitumen property on performance grade is the preferred category. Classification of modified bitumen based on performance grade makes it possible to provide perfect bitumen pattern in different climates.