The energy that can be extracted from the ocean is inexhaustible. An oscillating water column (OWC) is a wave energy converter that extracts this energy. A numerical investigation has been conducted by altering relative opening (α) and Orifice ratio (τ) to assess the maximal energy of a land-fixed rectangular-based OWC model in a nonlinear wave field. The power of OWC has also been evaluated by the wave steepness (H/L) alteration. The numeric analysis has been imposed to obtain the optimal power using Fluent software in a three-dimensional tank. Validation of the present numeric model’s result correlates with the printed empirical data. The Finite Volume Method (FVM) solves RANS equations, and the relevant waves are generated at the inlet of the numerical tank by the inlet velocity approach. The efficiency (η) increases with relative openings (α) increase. The efficiency (η) decreases with wave steepness (H/L) increase. The η reaches the optimum shown in the study at H/L = 0. 02 and τ = 1. 03% for entire values of α. The excellent energy of around 71. 3% is attained at α =75% and H/L = 0. 02. This study is a highly relevant source of information that finds the optimal efficiency of a land-fixed rectangular base OWC and gives prior knowledge of the performance of OWC before the real-life experiment.

Structures such as side Orifices, side weirs, and side sluice gates are known as flow diversion structures among which side Orifices have wide application in hydraulic and environmental Engineering. These flow diversion structures have been extensively used in irrigation and drainage networks, wastewater treatment plants, sedimentation tanks, etc. Therefore, Studying the pattern and characteristics of the flow -such as flow velocity components and free surface- adjacent to the side Orifice would be important. In this paper, the flow over a sharp-crested rectangular side Orifice in an open channel is simulated by FLOW-3D software. RNG k-e turbulence model is used to apply the Navier-Stokes equations and the VOF method is used to model the free surface profile changes. In the present study, the side Orifice discharge and flow patterns are obtained by numerical simulation and are compared with experimental data of Hussian et al (2011) for model verification. The amount of the discharges through the Orifice (both predicted by the present numerical simulation and recorded by the experimental research) are reported along with the relative errors which are about 8-9%. This shows relatively good agreement between numerical and experimental results. Therefore, the numerical model can be employed as a powerful tool for studying flow through side Orifices in open channels.The effects of the side Orifice crest's height (H) on the flow velocity components and free surface adjacent to the side Orifice are also investigated. Results indicate that the discharge ratio (ratio of the discharge through the side Orifice to the inlet discharge of the main channel) is increased with decreasing the height of the side Orifice crest. Maximum and minimum values for longitudinal component of the velocity -for all heights of the side Orifice crest- is reported at the beginning and end of the side Orifice, respectively. By decreasing the height of the side Orifice crest, these maximum and minimum values are respectively increased and decreased. Decreasing the height of the side Orifice crest, the longitudinal component of the velocity in the vicinity of the side Orifice is negative because of the reverse flow formed in this area. Examining the variation of lateral velocity component shows that this component is increased with decreasing the height of Orifice crest. That is why the amount of discharge through the side Orifice is increased with decreasing the height of Orifice crest.The flow direction is upward at the height level of 0.25H; therefore, vertical component of velocity trough the Orifice length is positive in all cases. On the other hand, the flow direction is downward at the height level 0.75H; thus, vertical component of velocity trough the Orifice length is negative in all cases. Absolute value of the vertical velocity is increased by decreasing the height of the side Orifice crest (H) because more flow is diverted to the side Orifice. By increasing the height of Orifice crest significant changes are reported in the free surface profiles especially in the vicinity of the side Orifice.

Submerged rectangular Orifice is among discharge measuring device which is suitable in small canal especially when the amount of fallis not adequat for application of weir, during the past decade many study have been conducted for evaluation of discharge coefficient of Orifice. For free the case of submerged Orifice only an average value of 0.61 has been mentiond in the literature. Since this coefficient depends to the flow characteristics and the Orifice dimensions, an equation for determination of discharge coefficient is needed. The development of such formula is the main goal of this study. To do so an experimental program was conducted and applying the dimensional analysis and data obtained from these tests, one relation was developed. This relation can be used where an accurate value of the discharge coefficient and consequently the flow discharge is needed.

Labyrinth weirs are one of the kind of nonlinear crest weirs causing the increase of discharge capacity for specified height of water level in canals and dams. In this study, the effects of dentate and Orifice labyrinth weirs on increasing the discharge capacity were investigated. Experiments were conducted in a laboratory flume with length of 12 m and width of 0.8 m. The nine experimental models with 15 cm height were used. The results showed that for L/W=2 and H/P=0.2, the discharge coefficient of the Orifice-dentate labyrinth weir and the dentate labyrinth weir are 75.6% and 17.5%, more than the simple labyrinth weir, respectively. However, dent and Orifice may decrease their efficiency in high heads and the discharge coefficient will be close to simple labyrinth weir. The reason for these changes was increasing the flow interference in downstream of labyrinth weir between dents, Orifices and weir with increasing discharge. Also, the result showed the efficiency of Orifice and dentate on labyrinth weirs will decrease with increasing the weir magnification (L/W) and they lose their effect.

Filling of locks in low lifts, generally accomplish by slots in gates and energy of flow dissipates by stilling basin and baffles. In this new system gate has been designed in the form of box and openings are made in two, upstream (U/S) and downstream (D/S) walls and flow control is done by these gates. This system includes a few Orifices in U/S and some under sluice in D/S. Some laboratory tests have been done for determining discharge coefficient (Cd). Results show that (Cd) for this system is different from (Cd) for Orifices and sluice gates. Generally the latter (Cd) is lower than the former. This is due to difference in Orifice edges and hydraulic loss between two walls. An equation has been developed in this research for multi dabble Orifices.

Using the control tools is an efficient method to decrease the responses of the structure under external excitations. In this regard, this study investigates the performance of two structures equipped with MR dampers and Orifice dampers under blast-induced vibration. In addition to stimulating the underground blast-induced vibration (due to the different nature of these loads), seismic excitation has also been used to evaluate the efficiency of these dampers. These dampers are semi-active devices, which change the output force of the damper by changing the input voltage and magnetic field of dampers. Also, in this paper, clipped-optimal algorithm was used. This algorithm can generate optimal damper force by changing the voltage at each time step based on the input forces. In this research, structural responses based on optimal and maximum voltage are considered. Also, the numerical results of the structure are compared with LQR algorithm. The LQR algorithm is considered a criterion for reducing structural responses to blast-induced vibration. The results indicate that the proposed method (the different locations and types of dampers) is efficient for decreasing the responses of the structure.

Introduction: Clinical use of the late responses during routine neurophysiological examination has significantly increased the diagnostic yield of the neurophysiological evaluation. The H max to M max ratio (H/M ratio) is considered a suitable index for illustrating the level of reflex excitability of the motor pool.Methods: In this study posterior tibial nerve H/M ratio changes in cerebrovascular accidents (CVA) evaluated. This investigation was carried out in 22 normal subjects aged 40-65 years with mean 52 years, and in 40 patients with CVA aged 42-63 years with mean 57 years.Results: In normal subjects no significant differences were found between the mean values observed between right and left sides. In patients significant increased H/M ratios in both sides with more in non-plegic leg (P<0.01) were found. The facilitation of Babinsky sign in patients is significantly associated with low H/M ratios (P=0.003). The H/M ratio changes were not significantly associated with severity of hemiplegia (P=0.3 for lower extremities, P=0.9 for upper extremities). The H/M ratio was increased in ischemic lesions (P<0.01), but in intracerebral hemorrhages the soleus H/M ratio increases in non-plegic side the same as the plegic side.Conclusion: The posterior tibial nerve H/M ratios are increased in CVA bilaterally due to decreased presynaptic inhibition Ia terminals, thus amplitude of H reflexes increased without increased amplitude of M response.