Scour holes formed downstream from a stepped spillway may affect the safety and stability of a structure. The development of such scour hole can cause failure of the structure by undermining the riverbed, thus it is important to develop criteria that result in understanding how such a scour hole can develop. The literature contains many studies dealing with energy dissipation, aeration and oxygen transfer in stepped spillways. However, their downstream scour hole depth and geometry is not well documented. In this study, a physical model is employed to study the impact of offtake channel BASE ANGLE of stepped spillways on the scour hole. The area of the longitudinal profile of the scour hole is used to evaluate the amount of scour at downstream from the stepped spillways. Experimental results showed that the takeoff ANGLE of 30o is the optimum ANGLE which gives minimum longitudinal area and maximum depth of the scour hole.

Statement of the Problem: Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance.Purpose: The purpose of this study was to evaluate the effect of gap ANGLE on the tensile strength of BASE metal solder joints.Materials and Method: A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered ANGLEs by employing an explicitly designed device. They were divided into 4 groups regarding the gap ANGLE; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10o, Group2: 20o, and Group3: 30o gap ANGLEs. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (p< 0.05).Results: The mean tensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p£0.490).Conclusion: Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint.

Background: Class II malocclusion is one of the most prevalent occlusion discrepancies. Knowledge of growth changes in craniofacial components can help clinicians plan orthodontic treatment, determine the proper timing to initiate the treatment, and predict the treatment outcome, especially in growth modification protocols. This study evaluates craniofacial skeleton changes in class II malocclusion subjects compared to class I malocclusion. Methods: In this cross-sectional study, cephalograms of 858 individuals aged between 7 and 23 were investigated. The samples were divided into the class I group (ANB ANGLE 0–, 4) and class II group (ANB ANGLE ≥,4 degrees), including 426 and 432 cephalograms, respectively, and each group was divided into seven subgroups considering age. Cephalometric analysis was performed using OnyxCeph software, and statistical analyses of variance, mean, paired t test, and independent samples t test were performed using SPSS software. Results: The results showed no significant differences between class I and class II groups in variables related to the cranial BASE and vertical facial height. In class II groups, the SNA ANGLE was significantly greater. The total mandibular height (Co-Gn), facial ANGLE (Npog-FH), and SNB ANGLE were significantly greater in class I compared to the class II group. Conclusion: Protrusion of the maxilla affects the formation of class II malocclusion, but an underdeveloped mandible is the main component of Class II malocclusion formation. With increasing age, especially after puberty, the mandible may become more retruded in class II patients.