The joint surface is widely distributed in the rock, thus leading to the nonlinear characteristics of rock mass strength and limiting the effectiveness of the linear model in reflecting characteristics. The JRC/JCS model is the nonlinear failure criterion and generally believed to describe the characteristics of joints better than other models. In order to develop the numerical program for JRC/...

Assessment and analysis of soil slope stability is an important part geotechnical engineering at all times. This paper examines the assessment in fine-grained soils. The effect change shear strength (?), stress (?) angle (?) on factor safety has been studied. It correlates with by considering horizontal seismic coefficients both saturated unsaturated conditions. failure surface was considered a...

the purpose of this study was to evaluate the shear bond strength (sbs) of orthodontic brackets bonded with two types of nano-composites in comparison to a conventional orthodontic composite.sixty extracted human first premolars were randomly divided into 3 groups each containing 20 teeth. in group i, a conventional orthodontic composite (transbond xt) was used to bond the brackets, while two n...

in this paper, dissimilar resistance spot welding of aisi 1075 eutectoid steel to aisi 201 stainless steel is investigated experimentally. for this purpose, the experiments are designed using response surface methodology and based on four-factor, five-level central composite design. the effects of process parameters such as welding current, welding time, cooling time and electrode force are inv...

objectives: micromechanical retention of resin cements to alloys is an important factor affecting the longevity of metal base restorations. this study aimed to compare the bond strength and etching pattern of a newly introduced experimental etchant gel namely nano met etch with those of conventional surface treatment techniques for nickel-chrome (ni-cr) and high noble alloys.  materials and met...

o bjectives: the purpose of this study was to evaluate the effect of salivary ph on the shear bond strength (sbs) of orthodontic brackets to tooth surface. materials and methods: eighty intact premolars were randomly divided into four groups of 20.  after bonding a bracket on each tooth, the groups one to four were stored in artificial saliva at a ph of 3.8, 4.8, 5.8, and 6.8, respectively for ...