JOURNAL OF CIVIL AND ENVIRONMENTAL ENGINEERING (UNIVERSITY OF TABRIZ)
Year:2010 | Volume:40 | Issue:1 (61)|Papers Count:7

In this paper behavior of long pile under lateral loading using PIV (Particle Image Velocimetry) method, in laboratory, was studied. In these tests the effects of inclination and stiffness of piles, were studied. The soil was made of loose poorly and fine sand (SP). The total length of pile was 40 centimeters and the embedded length of long pile was 37cm. For long pile, the inclined angles were: q=±5o, q=±10o and q=±15o. If the pile is under compression, it is considered positive, otherwise it is negative. After doing tests and analysis of the piles results, it was observed that the bearing capacity of batter pile is more than vertical pile, and the bearing capacity of negative batter pile is more than positive batter pile too. The piles results are observed that the effect of the inclined angle of the pile is more considerable than being positive or negative. For example the bearing capacity of+10o pile is more than -5o pile. It was observed also if inclined angle of the pile increases, the rigid length of pile will reduce, and for negative piles, this length reduces too. In batter pile, under lateral loading, the pile is taken under axial force, consequently cause more settlement.

The possibility of dam failures due to seismic forces, bombardment, piping, overtopping, or mal-designing and construction considerations is probable and can result in the most notable human life losses and extensive property damages. The knowledge of the propagation of the flood waves resulted by dam failure and the resistance effects of bed roughness on the flow velocity variation in the downstream of the dams have an important role in the hydraulics of free surface flows. In the present paper the rapidly varied unsteady flow caused by the failure of a model dam in a rectangular sloping rough channel with dry down stream bed has been analyzed theoretically using the characteristic method on the dimensionless form by means of computer and compared with experimental data existing in the literature. It is concluded that the positive wave front and drying wave front are highly sensitive to hydraulic resistance, consequently increasing the bed roughness causes to decreasing the flow velocity. Also by approaching the positive wave front, the flow velocity increases and tends to the value of wave front velocity. Finally, comparison revealed that experimental data of rough sloping channel agreed closely with the theoretical one. Thus this latest method would provide more satisfactory results for sloping rough channels.

Acrylonitrile is widely used as the main raw material in the production of acrylonitrile butadiene styrene resin (ABS) in the petrochemical industry and other industrial and commercial processes. Acrylonitrile is not easily decomposed by conventional treatment systems due to its toxic characteristics. If it’s not treated properly, it may cause profound damage to the environment. In this study, the performance of an aerated submerged fixed film reactor (ASFFR) has been studied for the removal of acrylonitrile from synthetic ABS wastewater. The experiments were conducted using a bioreactor in laboratory scale with 44.2 L capacity operated at different hydraulic and organic loading rates. The specific surface area and porosity of polypropylene media were 324 m2/m3 and 87% respectively. The reactor was loaded to provide hydraulic retention time (HRT) of 9, 7, 5 and 4 hr and soluble COD of 300 mg/L. The experiments were continued with the constant HRT 4 hr and variable COD concentrations of 350, 400 and 450 mg/L. The reactor demonstrated 95-99% removal efficiencies of SCOD and exhibited efficient and stable performance at organic loadings of 0.8-2.4 kg.AN/m3.day. When the organic and surface loadings were increased to 2.7 kg. AN/m3.day and 23.16 g. AN/m2.day respectively, the COD removal efficiency was decreased to 66% and the system became unstable. Also, different sorts of equations were set to show the relationships between organic loading rates as independent variables and different dependent parameters such as effluent SCOD and VSS concentrations. According to the experimental results, the ASFF reactor was determined as suitable approaches for the treatment of petrochemical effluents contain acrylonitrile.

It is impossible to estimate and ensure the safety of a double-layer space structure without consideration of the influences of uncertainties. In fact, precise manufacturing and assembling of such structure with hundreds or thousands of members is almost impossible and the existence of several imperfections such as non-rectilinearity of geometric axis of members, material and connection defects, initial lack of fit and residual stresses, which inherently has random nature, is inevitable. Consequently, the response of a real-life structure has also random nature. So this paper investigates the effects of these random imperfections on reliability of double-layer space structures by using Monte Carlo simulation method. OpenSees finite element software package is used to perform the numerical analysis. It is demonstrated that these random imperfections have significant influences on reliability assessment of double-layer space structures.

Cylinders with circular hollow sections (CHSs) are widely used elements in the construction of offshore structures such as jacket templates and jack-up rigs, because of their good resistance against bending, torsion and buckling, and a high strength-to-weight ratio. Since the circular cylinders in offshore platforms are subjected to sea waves having a random nature, study of a CHS element under the random waves can provide very useful information and leads to valuable results. Random wave induced forces are the functions of asymmetric pressure distribution around the cylinder and its temporal variation. In the literature, many published works have been focused on the study of the random wave induced forces on the circular cylinders and the pressure distribution around the cylinder under the random waves has not been considerably investigated. In the present paper, using experimental data, the pressure distribution around a circular cylinder is investigated and an equation is proposed for determination of pressure value at an arbitrary point on the surface of the cylinder. Utilized data are the results of experiments conducted on the circular cylinders under the random waves in the Delta wave channel of the university of Delft's hydraulics laboratory.

To avoid water and environmental pollution, the wastewater should be treated and reused. Novel methods of water and wastewater treatment are offered in environmental biotechnology using single cell organisms like micro algae. Since the removal of any contaminant is harmonized to its sanitary and environmental significance, nutrients removal has a specific concern due to emerge of eutriphication in water resources. The aim of this research is to study the behavior of micro algae in removal of nitrate- nitrogen and orthophosphate from municipal waste water. To find a strain which has a higher removal rate of NO3- -N and PO43- -P, 10 strain of micro algae were immobilized in sodium alginate gel and then inoculate in wastewater samples of Shiraz wastewater treatment plant for 12 days. The results show that Chlamydomonas sp. had removed 82.4% of nitrate- nitrogen and 71.9% of orthophosphate from wastewater and had the higher removal rate amongst other species. Likewise, Chlorella vulgaris had the highest oxygenation capacity. According to high growth rate and protein contents of micro algae, the biomass can be used in industries, agriculture, pharmaceutical and food industry.

In this paper, stress analyses in concrete sleeper has investigated by using results of the tests which have been done in main line of railway track. In these tests, special concrete sleeper (B70) installed in railway track. Five load cells fixed inside of the sleeper during constructing of that. After replacing this special sleeper with ordinary sleeper, and tamping in railway track, a train with certain axle load passed through that point of track. Forces on sleeper are analyzed (output of measurement). The results show that B70 concrete sleepers are designed well for tamped and no tamped cases. In the both cases, the stresses in sleeper cross sections are in allowed range. Also, the results show that the track without DTS operation (after replacing of the sleeper) decreases share of sleeper bearing and increases forces on adjacent sleepers. These forces together with dynamic effect of rail-sleeper interaction will accelerate sleeper's deterioration. This means that after replacing failured sleepers, the sufficient length of track must be operated by DTS and Tamping machines.