The diffraction of obliquely incident wave by a symmetric rectangular submarine TRENCH with the effect of SURFACE tension at the free SURFACE is investigated using two dimensional linearized potential theory. The reflection and transmission coefficients are computed numerically using appropriate multiterm Galerkin approximations involving ultraspherical Gegenbauer polynomials. These coefficients are represented graphically against the wave number in a number of figures. The theoretical observations are validated computationally. The derived result will coincide analytically and graphically with the results already present in the literature neglecting the effect of SURFACE tension, which confirms the correctness of the result presented here. We observed the zero reflection phenomenon in the graphical representation. It is also noted that the values of reflection coefficient decreases as the SURFACE tension increases. We conclude that realistic changes in SURFACE tension on the free SURFACE have a significant effect on the present study.

In the present work, CHARACTERIZATION of the SURFACE TRENCHes and vacancies with Amplitude Modulation AFM (AM-AFM) using Molecular Dynamics (MD) is simulated and the effects of the tip shape on the resulting images are investigated. The simulated system includes a recently developed gold coated AFM probe which interacts with a sample including a SURFACE TRENCH or a single-atom vacancy. In order to examine the behavior of the above system, including different transition metals, a Molecular Dynamics (MD) simulation with Sutton-Chen (SC) interatomic potential is used. Special attention is dedicated to the study of tip geometry effects such as the tip apex radius, the tip cone angle, the probe tilt angle, the tip apex atoms number, and the tip axis direction with respect to the FCC lattice structure on the resulting images.

Due to the loss of life and damage to SURFACE and underground structures, stabilization of TRENCHes in order to control and stabilize landslides is very important. In the current study, the effect of the implementation of the pile has been analyzed to increase the stability of the TRENCH under the impact of the earthquake. Therefore, a TRENCH with 45° angle which reinforced by the pile, was analyzed with variable parameters, including the diameter of the pile (D) that was with a 0.9m diameter and other pile with 1.5m diameter, the buried length of the pile (L) was 10m and 15m. The space between the piles (S) to each other was implemented by three sizes; 0.3m, 4.5m and 0.6m, and the implementation of the pile with five forms on the span of the TRENCH was analyzed to study its different behavior under seismic conditions. The results showed that with increasing the diameter of the pile and the implementation of the pile, the horizontal displacement of the span of the TRENCH reduces 25% to the normal state. In addition, with an increase in the length of the pile, the level of the subsidence is 24 to 30 percent lower than the normal state.

Excavation of TRENCHes by blasting is an important application of explosives. The number of pipeline TRENCHes blasted during the recent years has increased in many countries. However, excavation of narrow TRENCHes by blasting has had limited application. The intention of this study was to assess the feasibility of shallow and narrow TRENCH excavation in rock media by blasting. One major application of narrow TRENCHes is the placement of fiber optic communication cables. This paper presents the results of a blasting research work on construction of such channels. As a result of this work, a channel, 40 cm in width and 90 cm in depth, was excavated successfully. The specific charge used varied between 1.66 - 2.89 kg/m3 using gelatin dynamite as explosive charge. The initiation devices were of short delay Nonel, electric detonators (instantaneous and half second), and detonating cord (5gr/m & 10gr/m). The nominal burden was 50Cln and the effective burden was 43.8 cm. The blast hole spacing and sub drilling were 48 cm and 20 cm, respectively.

Background and Aims: When composite resin polymerizes, shrinkage stresses tend to produce gaps at the tooth/ restoration interfaces. SURFACE sealants may reduce or avoid problems related to the marginal interface. The aim of this study was to evaluate the effect of two different SURFACE sealants (Fortify and Optiguard) on the microleakage of class V resin composite restorations.Materials and Methods: Twenty three sound noncarious molars were collected. Totally, 45 Class V cavities with the occlusal margins in enamel and cervical margins in cementum were prepared in both buccal and lingual SURFACEs. The specimens were randomly assigned in three groups (15 cavities in each group) and then restored with a resin composite. After the finishing and polishing procedures, the restorations in each group were covered with a specific SURFACE sealant, except for the control samples, which were not sealed. After placing restorations, the specimens were thermocycled and then immersed in a 50% silver nitrate solution (tracer agent) for four hours, sectioned longitudinally and analyzed for leakage using a stereomicroscope in a blind manner. The marginal microleakage was evaluated at the occlusal and cervical interfaces and compared among the three groups using the Kruskall-Wallis and the Mann-Whitney U tests.Results: Microleakage was found in all groups at both occlusal and cervical margins. Significantly greater leakage was observed at the cervical margins compared to the enamel margins of the material groups (P=0.005).There was no statistically significant difference among the groups at occlusal margins (P=0.66). In the cervical region, Fortify showed improved results and statistically presented the lowest degree of microleakage (P=0.003).Conclusion: The used sealant materials presented different rates of effectiveness and Fortify decreased marginal microleakage significantly.

DIN 1.6580 low alloy steel has been plasma nitrided using the novel Through Cage (TC) plasma nit riding technique. Experimental results show that the thickness of the compound layer increases with temperature, as well as nitrogen percent, in the gas mixture, that an increase in screen hole size has no effect on the compound layer thickness under screen top lid conditions and, also, that an increase in screen hole size at the same temperature results in an increase in the thickness of the compound layer under iron plate top lid conditions. The results of micro-hardness measurements indicate that SURFACE hardness increases with temperature, as well as nitrogen volume, in the treatment gas. It was also found that the hardness values obtained using a screen top lid are relatively greater than those obtained using an iron plate top lid.

In this research, it is tried to investigate the soil erosion by the indices of rainfall erosive, evaluation of the basin potential for TRENCH erosion, morphometric of TRENCHes and statistical analysis to suggest some required recommendations for erosion control. Also we used hydro climatic indices for studying the above said factors. Also in relation with the high development of TRENCHes in the study basin, we did morphometric work in the 20 TRENCHes.With respect to steep slope of the skirts, great interfere of human (existence of 19 villages in the study basin), stormy rainfall, water way systems has caused the destruction and movement of non-resistant materials from the areas (fertilized agricultural soils)The average annual soil erosion in Kalgan Chayi basin is 235.79 ton/ha/y (table No.1) and the total erosion in whole of the area is 5552845 ton/per year.The index of wet soil (WS) in February and March were negative and indicates the potential of the under study area for TRENCH erosion in these months. Hydrothermal coefficient (HTK) 1.715 in the limit of 1.25 up to 2.5 shows the potential of the area soil for creating TRENCHes.Comparison of the results of statistical analysis by linear power regression showed that linear regression is better than power one in TRENCHes study.Some suggestions:Therefore, applying watershed management methods appropriate with the climatic and topographic conditions of the area are presented as the following:- Creating terrace at the mild slopes and making banquette (U, V gradients) at the pendants by using Sakardent formula which is adapted with semi-arid areas (by calculating distances, gradient and amount of earth filling and earth moving)- Applying watershed management methods of change in the slopes by dry laid masonry and establishment of weirs in the waterways and active TRENCHes (check dam and log) which their material exist in the environment.- Avoiding plow in the slopes (perpendicular to the contour lines) and preventing excessive and over grazing, burning bushes and trees.