From the environmental point of view, application of bioengineering techniques in civil projects such as landslide stabilization is given priority in recent years. In this paper, the influence of the diameter of tree roots on the increase of shear resistance of soil was investigated by means of series of in-situ direct shear tests. Thirty tests were carried out on a natural deposit CL soil containing midow roots by means of a set up designed in soil laboratory of SCWMRI. Since the existing roots in natural deposits have different diameters, a no dimensional index referred to as Root Diameter Ratio (RDR) was defined as the ratio of the mean root diameter to the maximum root diameter. The results showed, in general, the increased shear resistance of the soil due to the presence of roots was inversely proportional to the root diameters. In fact the apparent cohesion of soil increases considerably as the root diameter increases, while at the same time the internal friction angle decreases smoothly. However, the shear resistance growth stops at a given diameter, then stabilizes after a slight declination. A similar behavior was observed for the soil cohesion, while the internal friction angle showed a completely opposite behavior.

Measuring over 453 faults with slickenside lineation on 28 Karaj Formation localities in southern part of central Alborz, different methods including: conjugate faults analysis, R% method, fluctuation histogram of and right dihedra model were tested comparatively .On the basis of these methods, the arithmetic mean of the angle of internal friction determined to be 35.75 degrees in the whole study area. In different localities low internal angle coincides with high fracture density, low topographic relief and vice versa. Interception of misfitangle curve with ordinate axis shows astonishingly the same magnitude as the mean angle of rock-mass internal friction

The friction properties of granular materials play an important role in the determination of specifications for designing hoppers, transporting passages, dryers, silos and machines through which grain flows. In this study, the angle of repose and internal friction coefficient were determined for three common wheat varieties (Sardary, Gaspard and Saysoter) at four moisture contents (12, 15, 18, 21 w.b.%). Four contact surfaces (black, mild, aluminum and galvanized sheets) were used to measure the angle of repose. The tests were done in five replications. Analysis of variance was used to analyze the data and Duncan’s multiple range test was used to compare the effect of the means (P<5%). The results showed that the effects of moisture content, variety and contact surface were significant for the angle of repose. The effects of grain moisture content and variety were significant for the internal friction coefficient (P<1%). When moisture content of the grain increased, the angle of repose and internal friction coefficient increased significantly. Only where grain moisture level changed from 18 to 21% w.b. the internal friction coefficient did not change significantly. The highest and lowest internal friction coefficients belonged to the Sardary and Saysoter varieties, respectively. The highest and lowest the angles of repose belonged to the Gaspard and Sardary varieties, respectively.

Determination of cohesion and angle of internal friction of the asphalt is of special importance for designing and estimating the bearing capacity of asphalt mixtures. This is usually done by performing the triaxial test. To perform such experiment, however, advanced experimental equipments and experienced people are needed.In the present study, a new method to determine the cohesion and angle of internal friction parameters of the asphalt is introduced. This method is based on using the unconfined compression and indirect tensile tests instead of triaxial test to measure the shear strength parameters (C,f). In the present study, asphalt samples with different size distribution, percentage of filler, percentage of fracturing and percentage of bitumen were made and tested against Unconfined and indirect tensile experiments. Based on the results obtained from these experiments, the Mohr- Coulomb circles were plotted and cohesion and angle of internal friction of asphalt were determined using Mohr- Coulomb theory. To assess the validity of the results, the Hveem test was performed on the samples with similar characteristics as tested samples with unconfined and indirect tensile experiments and the relation among the results was obtained and analysed.

Designing and optimization of the intake manifold is one of the important steps in the development of the internal combustion engines. In this paper, the flow inside the intake manifold of an internal combustion engine is investigated by numerical modeling. The convective flux models are adopted to simulate the unsteady compressible flow behavior. To solve the governing equations, for calculating the flow specifications, a FORTRAN 90 code was written by the authors by different finite-volume methods. Three schemes, namely second-order averaging, first-order upwind and second-order Roe have been applied and their performance was compared in terms of computational efficiency. The inlet and outlet conditions are modeled by a combination of characteristics and extrapolation. To obtain better accuracy and a realistic flow model, wall friction and heat transfer terms have been included and the effects of friction and heat transfer on flow specifications have been investigated. For validation of our work, comparsions between our results and the other researchers have been done.

In this paper, numerical methods are utilized to investigate the analyses of the elastic and inelastic cyclic behavior of nine reinforced concrete columns having various reinforcement configurations under cyclic compressive load. The response curves of the columns are compared with that of experimental results. In this research, tow main and important concrete mechanical properties "cohesion" and "internal friction angle" are used for the analysis. To evaluate these parameters it is possible to utilize the only one single parameter as the concrete compression strength and the relevant equation proposed in this work. The results exhibit that the specimen's behavioral model for the complete period of loading and unloading regime, is affected by the complete stress-strain curve of concrete under monotonic load.

Background & Aim: Increasing economic role of medicinal herbs in recent society and complexity of modern technologies in production (planting and harvesting), transportation, storage, processing, quality evaluation, distribution, marketing and consumption of these products require a thorough understanding of their physical properties. Coefficient of friction of plant on the various surfaces is needed in designing of silos, storage of agricultural products and handling equipment, such as conveyors, and design of other equipment used in post harvest processing.Experimental: In this study, static coefficient of friction for two values of water content (wet basis) 58% and 53% for rosemary and, 65% and 63% for lavender on three surfaces, galvanized steel, glass and wood was investigate. For this purpose an apparatus made that includes an electrical motor and an optical sensor for precise measurement of the slipping moment of the product and its coefficient of friction.Results & discussion: Average values of maximum and minimum of static coefficient of friction that obtained for rosemary at 58 percent of water content were 0.87 on the wood surface and 0.46 on the glass, respectively. While at 53 percent water content, the maximum and minimum average values of coefficient of static friction obtained for rosemary were on wood, 0.66 and glass 0.38, respectively. The minimum average value of coefficient of friction for the lavender at 65 percent water content was 0.66 and on the glass however after the reduction of water content, at 63 percent water content, obtained 0.56 on the glass, too.Industrial and practical recommendations: The understanding of the engineering properties of herbal drugs for creating appropriate industrial procreation methods is of great importance.