Computation of longitudinal velocity in the vertical direction and extracting the applied theories have been conventional manner from past years among the hydraulic engineers. In many previous investigations, the researchers have tried to extract some applied equations, separately, by dividing the flow depth namely from bed to water surface to various regions. As it is accepted by all of the researchers, the laminar sublayer zone has a linear velocity profile while out of this zone, the velocity simulation follows a logarithmic law which its accuracy in estimation of the velocity decreases by increasing the distance from the bottom of the channel. Also, it is not applicable for dip phenomenon which occurs bellow the free surface. In the current study, 12 experimental data series, operated under different experimental conditions, were collected from previous researches. Also, three common theories of log law, log-wake law, and modified log-wake law have been applied to simulate longitudinal velocity profile in the vertical direction. Finally, it is seen that the modified log-wake law has a better agreement with the experimental data, and also it can be operated for predicting the dip phenomenon bellow the free surface. For solving the equation of the mentioned theory, the factors of von Karman, wake strength, and shear velocity are assumed unknown. Then, the mentioned parameters have been extracted using a non-linear optimization technique of the least square curve fitting.

In the present paper, the Zelt algorithm has been extended for ray tracing through an anisotropic model. In anisotropic media, the direction of the propagated energy generally differs from that of the plane-wave propagation. This makes velocity values to be varied in different directions. Therefore, velocity modeling in such media is completely different from that in an isotropic media.The velocity model for ray tracing is parameterized in terms of blocky trapezoid cells where the velocity changes inside the cells linearly. Thomsen's approximations in weakly anisotropic media were used to estimate anisotropic velocity vectors. Rays were traced in direction of group vector in the vertical transversely isotropic (VTI) media, whereas, the anisotropic Snell's law must be satisfied by the phase angle and phase velocities across the interface.The synthetic examples are given to demonstrate and verify the ray tracing algorithm. Reflected and turning waves were traced through the isotropic and anisotropic velocity models. Lateral and vertical velocity variation caused deviation on trajectory of the traveltime curve.The results show that the difference between isotropic and anisotropic traveltimes increases with offset, especially when the ratio offset/depth exceeds 1.5.

Study of turbidity current hydrodynamics plays an important role in increasing the economical life of dams though reduction in sediment accumulation. In the present experimental study, the effect of entrance densimetric Froude number of turbidity current in sub and super critical conditions (Fr=0.6-3.5) have been tested through effect of channel slope and change related to opening height of entrance gate on vertical distribution of flow velocity and currents' thickness under two dimensional flow conditions. The experiments were run in a 12 mlong by 0.2 m-wide by 0.5 m-high channel. Kaolin with the specific gravity of 2.65 and the mean particle diameter, D50, equal to 4.5 mm, was used as the cohesive suspended material. The results show that due to increasing in Froude number of entrance flow, the thickness of the turbidity current was increased while the layer-averaged velocity was decreased in the longitudinal direction. When the inlet densimetric Froude number reaches 0.7, the turbidity current tends to reach to a stable condition. Also the results show that the equivalent height of average velocity is about 0.8 times of the depth-averaged thickness of the current.

Introduction: Vegetation has traditionally been viewed as a nuisance and obstruction to channel flow by increasing flow resistance and water depth. However, in recent years, vegetation has become a major component of erosion control and stream restoration. Most of research efforts focus on describing vegetation roughness, determining drag coefficients and empirical formulas for resistance under various vegetation configurations. While the development of experimental solutions for vegetative resistance is important, understanding the detailed characteristics of flow through vegetation is also important. Yang et al. (2007) conducted flume experiments with different types of vegetation, and found that, in the cases of non-vegetated floodplains, all measured streamwise velocity distributions followed the logarithmic distribution, but for vegetated floodplains, they followed an S-shaped profile. Nezu and Sanju (2008) studied turbulence structures and coherent motion in vegetated canopy open-channel flows. They divided the whole flow region into three sub-zones, i. e., the emergent zone, the mixing-layer zone and the log-law zone. In the present study, a set of experiments have been designed under different conditions to elucidate the flow structure. The main focus is to examine how the vertical velocities, are affected by simulated vegetation arranged in emergent and submerged conditions. In addition, the effect of dowel density, configuration, and relative depth are examined. Methodology: The experiments were conducted in a fixed bed rectangular flume, 9 m long and 0. 6 m high and 0. 8 m wide. The slope of bed flume was 12 ×10-5. The main channel and floodplain had widths of 24 and 28 cm, respectively, and the main channel had a side slope, s, of 0. The bankfull height, h, was 6 cm. Vegetation were simulated by wooden dowels. The wooden dowels were 140 mm tall and 7 mm in diameter. The dowels were attached to a PVC sheet bolted to the bottom of the flood plain in linear and staggered arrangement. The spacing of the dowels varies from 2. 5-10 cm in both lateral and streamwise directions forming stem density of 0. 41, 1. 64%, 6. 04%. The flume was operated under a uniform flow condition, and measurements of discharge, point velocity and flow depth were taken. Flow depths were measured by means of a pointer gauge, discharges were measured by a digital flowmeter, installed upstream of the channel, and a micro propeller current meter were used to velocity measurements. Within the measurement cross section, located at 5. 6 m, the authors arranged ten verticals, where the lateral values of y from the first vertical to the last were 0, 4, 8, 12, 12. 2, 26 and 34 cm. When the vertical distance from the measurement point to the bed was less than 175 mm, the measurement interval was 10 mm and 5mm in the main channel and floodplain, respectively. Results and Discussion: The experimental results are presented in three parts, flow through non-vegetated floodplain first, flow through emergent vegetation second and followed by the submerged case. The effects of density and dowel configuration are included in each of the sections. Each section ends with a discussion on the effects of rigid dowels on logarithmic profile. In the cases of non-vegetated floodplains, all measured streamwise velocity distributions followed the logarithmic distribution, but for vegetated floodplains, they followed an S-shaped profile. It is seen that after implanting the vegetation over the floodplain, the velocity over the floodplain decreases whereas it increases in the main channel. Also, as the vegetation density, λ , increases, velocity increases in the main channel and decreases in the floodplain. In the presence of emergent vegetation on floodplain, logarithmic profile does not exist even in the main channel, however it seems that the formation of the S-shaped profile in the main channel is under the bankfull height and above the bankfull height the vertical velocity profile takes on a logarithmic profile again. On the basis of the present experimental results, the whole flow region is divided into the following three sub-zones: (1) Emergent zone (0 ≤ 𝑧 ≤ ℎ 𝑝 ), (2) Mixing-layer zone (ℎ 𝑝 < 𝑧 ≤ ℎ 𝑙 𝑜 𝑔 ), , (3) Log-law zone (ℎ 𝑙 𝑜 𝑔 < 𝑧 ≤ 𝐻 ). In the present study, hp was equal to 0. 2 H and hlog was equal to 0. 5 H. In the emergent zone (0 ≤ 𝑧 ≤ ℎ 𝑝 ) the velocity is almost constant due to strong wake effects of vegetation stems although it may behave slightly in a counter-gradient fashion. In the second zone (hp ≤ z ≤ hlog), the vertical velocity profile are similar in both submerged and emergent conditions, and the effect of bed roughness is completely eliminated and the velocity gradients are reduced and almost fixed. The velocity in the third zone (ℎ 𝑙 𝑜 𝑔 < 𝑧 ≤ 𝐻 ) is significantly higher than the velocity in the second zone. In the log-law zone (ℎ 𝑙 𝑜 𝑔 < 𝑧 ≤ 𝐻 ), the log-law of velocity distribution for rough beds is reasonably applied even to vegetated flows. Comparison the longitudinal velocity profiles for linear and staggered dowel arrangements indicates an increase in the resistance due to the linear arrangement compared to the staggered arrangement. Conclusion: In the cases of non-vegetated floodplains, all measured streamwise velocity distributions followed the logarithmic distribution, but for vegetated floodplains, they followed an S-shaped profile. However, in the main channel, higher than the bankfull height the velocity profile is logarithmic. The results shows that as the vegetation density, λ , increases, the velocity increases in the main channel and decreases in the floodplain. Linear arrangement resulted higher resistance compared to staggered vegetation arrangement. The velocity profile at all locations above the dowel array are very well represented by the following semi logarithmic expression. In fully submerged vegetation, the whole flow region was divided into three sub-zones, i. e., the emergent zone, (0 ≤ 𝑧 ≤ ℎ 𝑝 ) the mixing-layer zone (ℎ 𝑝 < 𝑧 ≤ ℎ 𝑙 𝑜 𝑔 ), and the log-law zone(ℎ 𝑙 𝑜 𝑔 < 𝑧 ≤ 𝐻 ). In the present study, hp was equal to 0. 2 H and hlog was equal to 0. 5 H.

Explosive forming of cone was investigated from some new analytical, numerical, and experimental aspects. In the analytical modeling, it is supposed that deformation profile of plate is a truncated cone during process, which will be deformed to a fully formed cone at the end of process. The variation of plate thickness was also neglected. Analysis required equations for determining vertical velocity and vertical displacement profiles during process; required pressure and final product dimensions are also given in this analytical model. ABAQUS/Explicit package was used for FEM simulation. The results of analytical model given in this paper are fully agreed with experimental and numerical (FEM) results.

Precise Estimation of water exchange between surface and subsurface flow in hyporheic zone which is habitat of microorganisms is vital. The temperature can be used as a tracer for estimation of water exchange through sediment water interphase. In this study, for the first time in Iran, an instrument was designed and constructed to make the measurement and recording of sediment temperature in the depth of hyporheic zone possible. In this regard, measurements were made in the Ziarat River of Golestan Province by the aforementioned instrument, and surface and subsurface water exchange rates were calculated using an extended conceptual model of heat transfer. For this purpose, in a 40 m interval of the river, 10 cross sections were selected at 4 m intervals, and at each cross section, temperature of 4 different depths of the riverbed (immediately below the bed, 0. 25, 0. 50, 0. 75 m) were recorded in July and January. The results showed that in all seasons there is a constant flow due to the difference of thermal potential between surface and subsurface of the river flow which leads to the transfer of nutrients to micro-organisms and consequently to the permanent self-purification of the river. The average of vertical exchange for July and January was 0. 34 mm/day and 0. 86 mm/day respectively.

Statement of Problem: Total removal of tissues and remnant microorganisms as well as canal shaping is the essential objectives of endodontic therapy. A successful endodontic treatment is obtained through Shilders principals, however; complete observation of this technique using stainless steel files manually is problematic and time-consuming. Modern technology, in order to eliminate such problems, has presented new facilities such as Nickel-Titanium (NiTi) files and engine driven instruments.Purpose: The aim of this in-vitro study was to compare the canal debridement efficiency of three engine driven instruments: Rotary, Reciprocal and vertical.Materials and Methods: In this experimental study, 60 mesial roots of human first and second mandibular molars were divided into three groups randomly. In each sample, one canal was considered as case, the other one as control. Files used in Reciprocal and vertical groups were of handy Ni-Ti type and in rotary group, rotary Ni-Ti files were used. After debridement, the roots were sectioned at 3mm and 5mm from anatomic apex, stained and examined under light microscope. Comparison criteria between case and control groups were based on residual debris and predentin and the level of root canal preparation and shaping after debridement. Data were subjected to kruskal-Wallis non-parametric test.Results: There was no significant difference between the efficiency of debridement at 3mm and 5mm sections between all groups. But difference in time consumption was significant ranked from the shortest to the longest as rotary, reciprocal and vertical.Conclusion: The efficiency of debridement between the three automated instruments was approximately equal, however; the instrumentation time was different between three groups. Rotary system was the fastest one, as compared with reciprocal (second) and vertical (last). It may be concluded that rotary system has a superiority over the other two groups in conventional root canal therapies.

Considering the significance of Zagros heights in precipitation distribution, the present study using the RegCM4 model and its simulations, the effect of Zagros heights on convective Cumulative precipitation and vertical velocity of different levels of the atmosphere was investigated. The required data was obtained from NCEP/NCAR with a 2. 5 resolution from 22 to 38 latitude and from 38 to 58 longitudes on a grille with a horizontal resolution of 10 KMs and 30 SEC time steps for 2000 to 2005. Comprehensive cumulative convective systems were evaluated in two control run an experimental run and, effects of the Zagros heights in warm and cold seasons of the year was examined on these parameters. Results indicated that cores of rainfall during December-January after crossing system have been weakened, while April systems in East Zagros have continued to operate with the same power. Zagros heights in the months of December-January increased rainfall in West Iran and reduced in the Zagros East. In contrast, in April, there is no significant difference between the two runs in the Zagros East between convective precipitations. And maximum precipitation in both runs, is focused in West Iran and Zagros region and its minimum is focused Zagros East and Iran's central plains; But by eliminating the Zagros heights, the convective rainfall this month has increased on the shores of the Caspian Sea. The Zagros heights has to effect on vertical wind velocity profiles of Low levels and the speed and extent of the jet stream cores of high levels of the atmosphere; So that in April resulted movement atmospheric jet stream from level 200 to 400 hp and increases their speed and extent; So, the flows pattern of the mesoscale convective systems and the convective precipitation resulting from them were influenced by the elevation pattern; and kind and how the Zagros heights effects on convective precipitation and vertical profiles of wind speed in the warm and cold months of year is different; in a way that, the wind slowed down at low levels of the atmosphere in December and increased in January and April.