مسعود غلامی

Asphalt mortar and asphalt mixture are viscoelastic materials due to the presence of bitumen in their structures. The master curves of dynamic modulus and phase angle developed through the horizontal shifting of the results using the appropriate shift factors are commonly used to describe the viscoelastic properties of asphalt mortar and asphalt mixture. In this study, constructing master curves of dynamic modulus and phase angle of asphalt mortar and asphalt mixture using the least number of test temperatures and frequencies was investigated. The dynamic modulus test was performed on asphalt concrete and asphalt mortar samples at six temperatures and frequencies. Then, the Laboratoire Central des Ponts et Chaussees method was used to determine the shift factors for constructing master curves. Also, the modified Christensen-Anderson-Marasteanu model was fitted on the master curves to predict their viscoelastic properties at an arbitrary temperature and frequency. In addition, the master curves and the fitted models which are created by using test results at two frequencies and six temperatures, six frequencies and three temperatures, or three frequencies and three temperatures, could provide the same predicted values and patterns as the original fitted model with more than 92% accuracy. So, as a result, it is possible to develop the master curves of the viscoelastic properties of asphalt mixture and asphalt mortar with a lower number of test results that have similar accuracy to the original master curves and reduce the time and cost of experiments up to 50%.

Asphalt mixtures and bitumens are faced with different traffic loading and thermal stresses during their lifetime. Due to their viscoelastic behavior, these materials exhibit different mechanical properties at different temperatures and traffic loading. Viscoelastic properties of bitumens are commonly expressed using the master curves of complex shear modulus (G*) and phase angle (δ) generally created by the horizontal shifting of the frequency sweep test results using shift factors. There are several methods for evaluating temperature shift factors, such as Williams, Landel, and Ferry (WLF) equation, modified Kaelble method, Log-Linear approach, and LCPC method. The LCPC method, developed using the Kramers-Kronig relationship, can be used to accurately evaluate the shift factor of bitumens, mastics, and asphalt mixtures. This study investigated the possibility of generating the master curves of bitumen based on temperature sweep test results rather than frequency sweep test results. Two types of bitumens were investigated in this study, neat bitumen with an 85-100 penetration grade (PG 58-22 performance grade) and SEPS modified asphalt binder with SEPS polymer content of 2, 4, and 6% by weight of the total binder. Temperature sweep tests were performed on all types of bitumens in a range of temperatures between 30 and 90 °C and the frequency of 1.59 Hz. Also, frequency sweep tests were performed on all kinds of bitumens in a range of temperature between 10 and 60 °C and a range of frequency between 0.1 and 100 Hz. The LCPC method was also investigated to calculate the shift factors for the master curves of complex shear modulus and phase angle, and the master curves of viscoelastic properties for all bitumen types are made based on temperature sweep and frequency sweep test results. The results indicated that the SEPS polymer could effectively increase the complex shear modulus and reduce the magnitude of phase angle. So, this polymer improved the rutting resistance of SEPS polymer-modified binders and led to better high-temperature performance of binders. In addition, the LCPC method effectively produced a valid and accurate form of the master curve using temperature sweep test results similar to the master curve using frequency sweep test results. Furthermore, the master curves of complex shear modulus (G*) and phase angle (δ) derived from temperature and frequency sweep test results exhibited comparable patterns and values. By plotting the value of complex shear modulus and phase angle obtained from the temperature sweep master curves versus the complex shear modulus and phase angle obtained from the frequency sweep master curves at the same reduced frequency, it was observed that all points were scattered in the vicinity of the y=x line. It was indicated that the master curves created based on temperature sweep test results have an acceptable approximation and accuracy with the master curves created based on frequency sweep test results. As a consequence, it may be preferable to generate the master curve of viscoelastic characteristics of bitumens using the results of the temperature sweep test, which is faster and more accurate in some conditions, compared to the results of the frequency sweep test.

Canola is one of the main oilseed crops. The effect of Azotobacter chroococcum as one of the biological fertilizer on the quantity and quality of rapeseed can be investigated. The presence of azotobacter in soils has positive effects on plants. Adequate moisture can promote vegetative growth, improve root growth, increase leaf area and durability, prolong flowering period, shoots, number of flowers and grain per pod, seed weight and yield. Moisture stress reduces the quantity and quality of these traits in rapeseed. The aim of this study was to find the right strain, suitable cultivar and appropriate irrigation regime for end of canola season water stress to save water in Lorestan province.

In order to evaluate the amount of protein, proline, soluble sugars and photosynthetic antioxidant enzymes, chlorophyll and carotenoids of rapeseed cultivars under the influence of inoculation of Azotobacter chrooccocum in cut off irrigation conditions, an experiment was conducted in the year 2016-2017 at Sarab Chengai Agricultural Research Station, Khorramabad as a factorial split plot with randomized complete block design with 4 replications. Experimental factors included discontinuation of irrigation at 30% flowering and 30% pod forming stages and optimum irrigation (control), Azotobacter chrooccocum included 63, 70 strains and non-inoculated (control) and three rapeseed genotypes including Neptune, Octane and Okapi (control).

Results showed that the effect of irrigation interruption on grain yield, proline content, soluble sugars, proteins, antioxidant enzymes and photosynthetic pigments of green tissue was significant. The effect of azotobacter chroococcum strains on all of these traits except grain yield and proline was significant. Rapeseed cultivars differed significantly in terms of seed yield, soluble sugars, enzyme catalase and chlorophyll b, and total chlorophyll a + b. in terms of the accumulation of proline, protein, peroxidase enzyme, carotenoid, chlorophyll a And the chlorophyll a/b ratio was not significantly Different between cultivars. The highest levels of proline, soluble sugars, antioxidant enzymes were obtained in the irrigation cessation treatment from the 30% flowering stage and the highest amount of protein and photosynthetic pigments were obtained from the normal irrigation treatment. Inoculation of rapeseed with Azotobacter chrooccocum strains increased the protein, total chlorophyll and carotenoid of the compared to the non-inoculated treatment. Octane and Neptune hybrids outperformed the total chlorophyll a+b of aerial organisms in terms of the enzyme catalase. However, the Okapi (control) cultivar was superior to octane and Neptune hybrids in terms of soluble sugars. The highest grain yield (4559 kg / ha) was observed in the optimal irrigation (control). In the irrigation cut-off 30% of silique and 30% flowering stages, decreased grain yield (5.99% and 23.65%, respectively) compared to optimal irrigation. Seed yield of Octane and Neptune cultivars were 4584 and 4290 kg ha-1, respectively, which were 24.7% and 19.6% more than Okapi (control) cultivars, respectively.According to the results, Interaction Effects showed that rapeseed cultivars produced the highest protein content in the treatment of normal irrigation and inoculation with 63 and 70 Aztobacter chroococcum strains. The lowest green organ protein was obtained from treatments of noninoculated and irrigation discontinuation from 30% flowering and 30% pod forming stages. Irrigation interruptions led to a significant increase in proline concentration in canola. In irrigation cessation treatment, 30% flowering and normal irrigation were observed with the lowest and highest proline concentrations, respectively. Probably related to its role in regulating osmosis to stabilize cellular membranes and proteins, inhibiting free radicals under stress. Irrigation witholding at 30% flowering and 30% pod forming resulted in a significant increase in antioxidant peroxidase and catalase enzymes activities. Azotobacter chrooccocum strains significantly reduced the levels of peroxidase and catalase enzymes in the rapeseed aerial parts. It is possible that by inoculating the Azotobacter chrooccocum, the plant is less likely to show signs of stress. Irrigation discontinuation significantly reduced chlorophyll a, b, and total levels compared to normal irrigation, possibly due to increased chlorophylase enzyme activity. The interactions between irrigation interruptions, azotobacter inoculation and rapeseed cultivars on the amount of chlorophyll a showed that Neptune and Octane hybrids produced the highest amount of chlorophyll a in the treatment with 70 strain in normal irrigation treatment. The same effects on chlorophyll b levels showed that the highest chlorophyll b levels were observed in octane and Neptune hybrids at 63 and 70 strains in normal irrigation and the lowest chlorophyll b content was observed in octane-free treatment without inoculation with irrigation cessation treatment from 30% flowering stage. Octane hybrid produced the highest total chlorophyll a + b in normal irrigation and bacterial inoculation of the strain 70. The highest accumulation of carotenoids was 0.430 mg g-1 FW in octane hybrid in strain 63 and normal irrigation. The lowest accumulation of carotenoids in was obtained from the untreated bacterium. The concentration of soluble sugars in the cultivars varied. The highest soluble sugars in the Okapi cultivar weighed 56.341 mg g-1 FW and produced less sugar Neptune with 54.89 and octane with 51.960 mg g-1  FW. Therefore, it seems that the accumulation rate of these osmotic regulators is related to higher drought resistance of cultivars.

In order to evaluate the yield and nutrient accumulation in different cultivars of rapeseed under the effect of azotobacter in irrigation conditions, a factorial split experiment based on randomized complete blocks design with four replications was conducted in Khorramabad agricultural research station in 2016-2017. Experimental factors included the withholding irrigation from 30% flowering and 30% pod forming, and normal irrigation (control) as the main plot and inoculation of  Neptune, Oktane and Okapi rapeseed cultivar seeds with azotobacter strains (63, 70) and non inoculation (control)as subplots. The results showed that the irrigation regimes had a significant effect on grain yield and the accumulation of nitrogen, phosphorus, potassium, calcium, magnesium, and manganese in shoot and seeds. The effect of azotobacter was significant on all nutrients (except magnesium) uptake in green tissue and seeds. The interaction effects of irrigation regime, bacteria and cultivar were significant on phosphorus, potassium, magnesium, manganese, and zinc levels in shoot and grain. Maximum grain yield was obtained from optimal irrigation treatment with 4559 kg.ha-1. It was found that Oktane and Neptune cultivars with 4584 and 4290 kg grain.ha-1were superior compared to okapi cultivar. With regards to the positive effect of potassium concentration and inoculation of rapeseed seeds with azotobacter due to its solubilizing properties, increasing the application of potassium in soil and seed inoculation can moderate the negative effects of stress and improve grain yield in rapeseed.

Concrete pavements are widely used by pavement engineers due to their advantages over flexible pavements such as longer lifetime, good performance and durability, etc. However, concrete pavements represent some drawbacks such as shrinkage that increases the tensile stress in concrete, which may lead to cracking, warping, etc. Drying shrinkage is the most important type of shrinkage in concrete pavements. polypropylene fibers can be used to control or reduce width of cracking by bridging both sides of crack. In this study, the effect of Emboss fiber on the behavior of concrete pavement was investigated. Slump, compressive strength, third-point flexural strength, electrical resistance, skid resistance, free shrinkage and restrained shrinkage by ring test were performed. Two water-cement ratios of 0.35 & 0.4 were used for mix design and the percentage of polypropylene fiber used in mixtures was respectively 0.44% by concrete volume. The results showed that the use of Emboss Fiber reduced the workability of concrete. Also, these reinforcements had different effects on compressive and flexural strength and electrical resistance depend on homogeneity of Emboss fiber reinforced concrete. Furthermore, toughness indices and energy absorption of concrete were significantly increased by using Emboss fiber reinforced concrete. In addition, using fiber indicated a slight reduction in the amount of free and restrained shrinkage and occurrence of first-crack. polypropylene fibers had a key role in controlling crack width by bridging both sides of crack. Finally, no certain relationship was observed between using SRA and changing the skid resistance of concrete pavement.

Concrete pavements are widely used by pavement engineers due to their advantages over flexible pavements such as longer lifetime, good performance and durability, etc. However, concrete pavements represent some drawbacks such as shrinkage that increases the tensile stress in concrete, which may lead to cracking, warping, etc. Drying shrinkage is the most important type of shrinkage in concrete pavements. To prevent or reduce the amount of cracking, shrinkage reducing admixture (SRA) can be used. This admixture controls shrinkage by reducing water surface tensile in capillary tubes. In this study, the effect of shrinkage reducing admixture on the behavior of concrete used in concrete pavement was investigated. Slump, compressive strength, third-point flexural strength, electrical resistance, skid resistance, free shrinkage and restrained shrinkage by ring test were performed. Two water-cement ratios of 0.35 & 0.4 were used for mix design and the percentage of shrinkage reducing admixture used in mixtures was 2% by weight of cement. The results showed that the use of SRA had negligible effect on workability. Also, the use of SRA caused about 10% reduction in compressive and flexural strength and electrical resistance. Furthermore, a reduction of 10% and 20% was observed in free and restrained shrinkages, respectively, followed by a 40% reduction in crack width and more than one week delay in occurrence of first crack. Finally, no certain relationship was observed between using SRA and changing the skid resistance of concrete pavement.

An important issue with respect to the hydraulic power systems is the frequency stabilization. To design Load Frequency Control (LFC) with high efficiency, control parameters need to be adjusted so that the system frequency remains stable even under changeable conditions. Controlling the frequency and changes in the turbine time constant requires that three term control parameters of Proportional-Integral-Derivation (PID) and Transient Droop Compensators (TDC) in hydraulic power systems be adjusted separately, without considering the damping parameters simultaneously with the load working condition. Owing to the significance of the above issues in hydraulic power systems, this paper aimed to study the adjustment of parameters using the methods of Particle Swarm Optimization (PSO), Desired Time Response Specification (DTRS), and Maximum Peak Resonance Specification (MPRS). The obtained results of simulation revealed that the method of Desired Time Response Specification (DTRS) is superior to the other methods under most conditions considering the frequency deviation and turbine output power.

The importance of vessel structure has been shown in pathogenesis of the equine and bovine laminitis. Investigation on vessel structures is necessary to diagnose the mechanism of laminitis. Due to lack of literature on ovine digital arteries. Ovine digital vessels were studied using corrosion casting method. The hind limbs of 15 lambs of 3 months ages were separated from tarsus joint. After the dissection of dorsal metatarsal artery, normal saline and resin metacrylat were injected into the vessels. In this species, the dorsal common digital artery and common plantar digital artery have the main function in blood supply. One branch runs to the heel bulb and the other runs to the axial wall and sole. The third branch of these arteries is responsible to blood supply of periople tissue. The common dorsal digital artery and abaxial proper digital artery drain all venous blood from the claw. The dorsal proper digital artery arises from the numerous smaller veins which are joined to form the deep and superficial venous networks of coronary margin and wall. This vein delivers blood to the common dorsal digital artery. The axial proper plantar vein drained into the abaxial proper plantar vein. Two main vessels which arise from venous network of wall, sole and plantar surface of the bulb, drain into the abaxial proper plantar vein.