The present research describes the variations of the intermediate principal stress, σ2, in plane strain condition which occurs in many earth structures, such as embankment dams, retaining walls and strip footings. For this purpose a series of drained monotonic plane strain tests on Leighton Buzzard sand under different initial magnitudes of σ2 were performed. The sand samples were initially packed to dense and loose samples. The Biaxial Tester, which is able to simulate the plane strain condition and also to measure the variation of σ2 during the test, was employed in the research. It is shown that the stress-strain response of sand and its shear strength at failure do not vary significantly and almost independent of the initial magnitudes of σ2, but are dependent on its initial void ratio. This implies that if different initial values of σ2 create various directional anisotropic structures, they play no part in the plane strain tests. Also a numerical model, which is capable of including σ2, is proposed to predict particularly stress-strain response of sand and magnitude of σ2 at failure. The variations of stress ratio σ2/(σ1 + σ3) were monitored during shearing to clarify the significance of intermediate principal stress.

The Granular soil has a complex macroscopic response under seismic loading. Due to the many uses of the results of cyclic triaxial tests, the numerical modeling of these tests is needed to facilitate the prediction of soil behavior and reducing the cost of laboratory tests. The aim of the present research is to evaluate the ability of the discrete element method to investigate the dynamic behavior of sand by simulating a number of drained stress-controlled cyclic triaxial tests under three-dimensional conditions. In addition, the effect of parameters such as the number of loading cycles, soil relative density, cyclic stress ratio, particle shape and loading paths on the dynamic properties of soil (shear modulus and damping ratio) is also considered. The results indicate that numerical simulation by the discrete element method can accurately represent the variations of soil dynamic properties with the considered variables. The comparison of experimental results from the literature and numerical models carried out in this study shows that the rate of decreasing in shear modulus and increasing in damping ratio of the samples with non-spherical particles with shear strain is higher in the given cyclic stress ratio and porosity. The cyclic stress ratio does not significantly affect the shear modulus, damping ratio and the coordinate number of samples. The coordinate number of the sample with spherical and non-spherical particles (e=0.3) is obtained 7.7 and 6.4, respectively, at the end of the simulation test. In the same condition, the samples with non - spherical particles have undergone more deformations.

Soil reinforcing is one of soil improvement methods by using of reinforcing Materials (with suitable performance in tension) in soil (with fairly compressive strength and weakness in tension). In recent years, numerous studies have been carried out about the application of reinforced soil and bearing capacity of Granular soils. Generally, these studies are limited to reinforced embankment with geosynthetics and steel stripes and even plastic parts. So using of plastic waste to improve the bearing capacity of embankment has not been considered. Therefore, in this research the effect of plastic wastes to improve the bearing capacity of Granular soils has been investigated. The variables considered are using one type of disposal plastic wastes in different weight percentages at irregular (random) reinforcement and regular reinforcement (with specified layers) in Granular embankment. The research was carried out in small laboratory scale using CBR tests. According to results, placing plastic waste parts in sandy soil increases the bearing capacity remarkably. The optimum values were obtained at 2% to 2. 5% plastic weight ratios to soil weight. Also the required energy conditions to attain optimum percentage were investigated. In this regard, the strain-stress behavior of soil was studied. The results show that increasing of plastic parts to 2%-2. 5% at irregular and regular condition, respectively, raises the soil elasticity coefficient to 234 and 152% respectively.

One of the intrinsic properties of foams, porous Materials, and Granular Materials, are their ability to mitigate the blast wave. The current research study investigates the capability of Granular Materials in the mitigation of blast wave both experimentally and numerically. In the experimental section, the explosion shock tube facility was employed to conduct a series of experiments. Sawdust and mineral pumice were used as Granular Materials in the sandwich panel core and their mechanical properties were obtained by performing quasi-static compression tests. Moreover, the commercial hydrocode AUTODYN was used to numerically simulate the process while the smooth particle hydrodynamics method (SPH) was employed to model Granular Materials. The obtained results indicate that mineral pumice leads to more mitigation of the blast wave compared to sawdust. Besides, using a low thick core made of Granular Materials is not considerably effective and using a high thick core leads to more mitigation of the blast wave.

Resilient modulus and California Bearing Ratio (CBR) in unbound Granular Materials are the key technical characteristics of layers in a flexible pavement design. Among the factors affecting these two parameters, the aggregate gradation is the most important. Using particle size distribution curve developed by AASHTO, together with other considerations mentioned in the related regulations have yielded desirable results in many cases. However, many roads loaded by heavy vehicles, for which all technical instructions of standard regulations were observed, have undergone deformations caused by subsidence of layers. According to the related technical documents, one hypothesis could be the proximity of aggregate gradation to the boundary areas. Therefore, the aim of this study was to determine the effect of changes in the scope of aggregation in the border areas on strength parameters. For this purpose, effects of aggregate grading variation on two types of aggregates, i. e. limestone and quartzite (as determined by AASHTO) were investigated using specific gravity, CBR, and resilient modulus tests. The results showed that, in the gradation boundaries determined by AASHTO, the difference between specific gravity values was insignificant. In the CBR and resilient modulus tests, however, there was a significant difference between test results in the upper and lower limits of gradation. In addition, gradation variation had a lower impact on resistance parameters in quartzite aggregate compared to limestone aggregate. Therefore, under special utilization conditions, Materials with highest values of technical specifications should be used, since even Materials whose technical specifications are in the standard range may not behave as expected in real world situations.

Subjected to external loads, Granular Materials experience severe deformation in a narrow zone before their failure. This phenomenon, which is called strain localisation or shear band, is of vital importance in assessing the stability of the geotechnical structure, studying the stress-strain behaviour of soil and rock Materials, and analysing the interaction of soil and structure. The present study is aimed to investigate the effect of various factors on the pattern and inclination of shear band in a general three-dimensional condition of stress using the Discrete Element Method (DEM). Several tests were simulated using a developed version of the TRUBAL program called GRANULE. The GRANULE code was further developed to add the capability of carrying out simulations with different intermediate principal stresses and modelling specimens containing non-spherical particles. The shear band was detected by tracking the motion of the particles and plotting the rotation distribution of particles within the sample. The results prove that the shear band inclination and its pattern, are greatly affected by intermediate principal stress, particle shape, and confining stress. Moreover, it was observed that the change in the b value plays a key role in the alteration of the 3D configuration of the shear band.

Objective: Toxoplasmosis, caused by an intracellular protozoan parasite, and the Toxoplasma gondii, is widespread throughout the world. In recent years, significant progress has been made in the identification of vaccine candidates which could induce a protective response. GRA7, an excretory 29 kDa Toxoplasma gondii a dense Granular antigen released by infected host cells. In tachyzoite-infected cells, p29 accumulates within the parasitophorous vacuole and co-localizes with its delimiting membrane. Materials and Methods: In the present work, first genomic DNA of Toxoplasma gondii was extracted and used for amplifying of GRA7 gene as a template. Then PCR product was extracted from agarose gel and cloned into TOPO vector. The plasmid containing GRA7 gene was extracted from the transformed bacteria (TOP10 strain) and sequenced. Results: Sequence analysis of GRA7 gene cloned into TOPO vector showed only one base difference when composed with the gene bank sequence for RH strain was only one base. Conclusion: The results indicated that this clone is suitable for subcloning in Prokaryotic and Eukaryotic plasmid.