Effect of Collar-Slot Combination on the Local Scouring Around the Bridge Piers (original) (raw)
Related papers
Physiology and Pharmacology, 2007
Introduction: Previous studies have shown that low frequency stimulation (LFS) has an inhibitory effect on kindling acquisition. However, the mechanism of this effect has not been completely determined. In the present study, the effect of LFS of the perforant path on seizures induced by rapid perforant path kindling was investigated. Methods: Animals were kindled by electrical stimulation of perforant path. One group of animals (n=6) received LFS (0.1 ms pulses at 1 Hz, 200 pulse, and 50-150 µA) after termination of each kindling stimulations. In control groups, animals received only kindling stimulations (n=8) or LFS (n=4). Basal field potential recording and paired pulse stimulations were done every day, before kindling stimulations. Results: Application of LFS significantly retarded the kindling acquisition and increased the number of stimulations to achieve different seizure stages [F(4,60)=10.9, P<0.0001]. LFS also prevented increment of slope of field excitatory postsynaptic potentials and population spike amplitude during kindling (P<0.001) (There was 88.6±1.7% increment in fEPSP and 94±2.3% increment in PS in kindled group and 3.5±.05% increment in fEPSP and 12.3±0.1% decrease in PS in kindled+LFS group). In addition, LFS significantly prevented the marked increase in early (10-50 ms intervals) and late (300-1000 ms intervals) paired pulse depression induced by kindling (P<0.01). Conclusion: According to obtained results, it may be suggested that LFS of perforant path has a significant antiepileptogenic effect on perforant path kindled seizures through inhibition of synaptic transmission in dentate gyrus. Meanwhile, LFS prevents compensatory increase in the paired pulse depression during kindling acquisition.
Hydraulic and Structural Analysis of Babolrud River Training Using Some Applied Software
DOAJ (DOAJ: Directory of Open Access Journals), 2019
Occurrence of heavy floods in rivers causes a lot of damages and losses. In this research, to highlight the river-training reaches in 10.9 km of Babolrud River, first, using topographic map of the area, the Tin layer was created in GIS software. Then, using the HEC-GeoRAS extension, the main route and cross sections of the river were prepared and introduced to the HEC-RAS model. River discharge with return periods of 2 to 200 years was calculated. Flow analysis in the agricultural and urban areas was performed and the areas which need training measures such as flood-retaining walls and levees were specified and designed. The structural design, stability control and sliding was performed based on the Standard No. 518, using RetainWall software, and design and control of levee stability was performed based on the Standard No. 214, using GeoStudio software. The cost of project implementation was estimated based on the Price List of 2017. The output of HEC-RAS software showed that height of flood-retaining wall in 3 urban reaches ranged between 1.73 to 2.8 m and in 5 agricultural reaches ranged between 1.46 to 2.25 m. It was concluded that the overall cost of levee implementation is about 9.01 billion Rials, of gravity concrete flood-retaining wall is about 9.26 billion Rials and of concrete cantilever inverted T shape flood-retaining wall is about 10.05 billion Rials. Thus, using floodretaining levee is the most economical option.
2008
The effect of removal of smear layer has already been a subject in many investigations, and has been a matter of controversy. Of course there is no doubt that sealer penetration would be facilitated when smear layer removed. The aim of this study was evaluation of the relationship between sealer penetration and apical microleakage after usage of MTAD. Materials & Methods: In this invitro study, 135 human single root extracted teeth were selected. The teeth were divided into three groups (40 samples in each) as experimental groups as follow: Group 1: Serum was used for irrigation (with the smear layer). Group 2: EDTA 17% was used for irrigation (removal of the smear layer). Group 3: MTAD was used for irrigation (removal of the smear layer) and 15 teeth were considered as the control. The teeth in each group were divided into two subgroups (20 teeth) to be filled either with AH Plus or Dorifill sealer. Sixty teeth were selected for dye penetration with methylene blue and statistically analysed using One-Way and Two-Way ANOVA. In the other 60 teeth, sealer penetration was evaluated using SEM. The data were statistically analysed using Kruskal-Wallis and Mann-Whitney tests. The end relationship between dye penetration and sealer penetration was evaluated by spearman correlation test. Results: There was no significant difference between the three types of irrigants. There was a significant difference between the two sealers. AH plus revealed less dye penetration. Minimum dye penetration was observed in MTAD group with AH Plus and maximum dye penetration was observed in Serum group with Dorifill. Sealer penetration in MTAD and EDTA groups were better than Serum group. AH Plus was better than Dorifill. The correlation between sealer penetration in dentinal tubules and dye penetration wasn't statistically significant. Conclusion: Type of irrigant didn't affect apical microleakage but type of sealer affected microleakage. AH Plus proved to be better. AH Plus showed greater sealer penetration. Greater sealer penetration does not necessarily reduce apical microleakage.
Research on Animal Production
In the current study, two groups of lines Coturnix Japonica Quail that were selected for hig (HW) and low (LW) body weight at the age of 4 weeks for 7 generations were used. HW line after selection for 7 generations was significantly heavier than LW line in the same generation at the age of 28days (p<0.01). 21 females, and 11 males from the HW, 18 females and 10 male from the LW lines were mated in the reciprocal cross to produce two groups, one group with HW male parents and the other group with LW male parents. To determine the reciprocal and heterosis effects for hatch weight and 4 weeks body weight and also for reproductive traits including age at sexual maturity, weight of sexual maturity, percentage of fertility and percentage of hatching, the groups produced by reciprocal crossing were compared with parental lines. The differences between two lines were significant for the mean of all traits except for egg number (P<0.01). The effect of heterosis was significant for age at sexual maturity, percentage of fertility and percentage of hatching but was not significant for other traits. The maternal or reciprocal effect was significant for all traits except for egg number trait (P<0.01).
Thin-Walled Structures, 2016
In in this paper, cyclic behavior of SS316L cubic shells under pure torsional load was experimentally and numerically studied. Experimental tests were carried out by a servo-hydraulic NSTRON 8802 machine under torsional load-control condition. In this loading condition and based on experimental results, due to the existence of larger shear stress along the shell thickness, increasing of torsional torque amplitude caused the enhancement of ratcheting angle and reduction of shells's life. Also, the effect of cutout and its size on ratcheting behavior of cubic shell were investigated , According to experimental results, it was seen that the sensitivity of ratcheting angle to cutout position near the applied load was high and the shell's life decreases in this condition. Numerical analysis was done by Abaqus software and using the nonlinear isotropic/kinematic hardening model. There is a good agreement with that of experimental results.
The effect of wood species on particleboard properties
تحقیقات علوم چوب و کاغذ ایران, 2010
In this study, particleboard was produced by Eucalyptus and Poplar wood mixture. Variations of this study were as follow: - Combinations of Eucalyptus and Poplar wood were (%100 , %0) , (%66.5 ,% 33.5) , (%33.5 ,% 66.5) and (%0 ,% 100) respectively. - Resin content ( %8 and %10) Physical and mechanical properties of boards such as MOR, MOE, IB TS2 and TS24 were tested according to EN standard. The effects of raw materials combinations on bending properties were significant. Maximum of MOE and MOR were observed in %66.5 of Poplar wood and % 33.5 of Eucalyptus wood. As expected, Physical and mechanical properties of boards were improved by increasing of resin content. Results indicated that TS2 and TS24 were increased with increasing of Poplar wood in combinations. Also the minimum of these properties were obtained in combinations of Eucalyptus and Poplar wood, %100, %0 respectively.
Seismic Wave-Field Propagation Modelling using the Euler Method
Journal of Computational Methods In Engineering, 2020
Wave-field extrapolation based on solving the wave equation is an important step in seismic modeling and needs a high level of accuracy. It has been implemented through a various numerical methods such as finite difference method as the most popular and conventional one. Moreover, the main drawbacks of the finite difference method are the low level of accuracy and the numerical dispersion for large time intervals (∆t). On the other hand, the symplectic integrators due to their structure can cope with this problem and act more accurately in comparison to the finite difference method. They reduce the computation cost and do not face numerical dispersion when time interval is increased. Therefore, the aim of the current paper is to present a symplectic integrator for wave-field extrapolation using the Euler method. Then, the extrapolation is implemented for rather large time intervals using a simple geological model. The extrapolation employed for both symplectic Euler and finite difference