Engineering Commons^™

Behavior Of Square And L-Shaped Slender Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Wen Hu Tsao

Dissertations

A numerical analysis was developed to evaluate the complete load-deflection and moment-curvature relationships for square and L-shaped slender reinforced concrete columns subjected to biaxial bending and axial load. This computer model can be used for any cross section geometry and material properties of normal concrete. The analysis was based on a deformation control and both the ascending and descending branches of curves can be studied. The finite difference method was introduced to calculate the deflections which satisfy the compatibility equations. Six square slender columns and eight L-shaped slender columns were tested to compare their experimental load-deformation results with the analytical …

Frictional Resistance Of Geotextiles, Md. Khairul Alam

Theses

The pullout resistance of geotextiles was examined using pullout tests. A suitable wooden box with large (2 ft x 2 ft x 4 ft) dimensions was used to avoid the effect of boundary and to simulate field conditions. Two types of failure patterns were observed. For shallow embedment (<3 ft), geotextile produced a movement of the surrounding mass of sand in the shape of an inverted cone due to interlocking friction between geotextile and sand particles. The cone angle decreases with increase in depth of embedment. For embedment equal to or greater than 3 ft., no sand cone developed and the failure occurred along the interface of geotextile and sand. For 1 ft. surcharge, the increase in the pullout resistance due to combined horizontal and vertical embedment was about 30 %.

Influence Of Heavy Metal Concentration On Rotating Biological Contrator Performance, Huei-Sheng Cheng

Theses

Seven heavy metals ( Fe⁺², Mn⁺², Zn⁺², Ag⁺, Pb⁺², Cu⁺², Cd⁺² ) at various concentrations were investigated in a Rotating Biological Contactor (RBC) system. The experimental data indicated that the degree of heavy metal toxicity in the biological system mainly depended on the ratio of inflow heavy metal concentration to organic loading. The optimal ratio of heavy metal to organic loading was determined on the basis of the maximum removal of chemical oxygen demand (COD) under different operating conditions. In addition, the effect of heavy metal on …

Disc Size Scale-Up In Rotating Biological Contactor System, Chi-Sheng Chang

Theses

Disc size scale-up of prototype and small-scale RBC plants are successfully developed by applying the 114 data sets obtained from 12 RBC plants to the evaluation of percent sBOD remaining. These data analyses are performed by the least square method, therefore, the scale-up factors of the prototype and the small-scale are determined at different hydraulic loading. Furthermore, the relationship between scale-up factor and the disc diameter are established under the given flow rate, the number of stages, and the number of discs. A group of Curves are obtained and can be utilized for the full-scale RBC plant preliminary design. The …

Centrifugal Modeling Of Leaking Underground Storage Tanks, Kuo-Neng George Chang

Theses

There are between 2 to 3.5 million Underground Storage Tanks (UST) located through this nation. Most of these tanks store gasoline and fuel oil. Many tanks in fact are or will soon be leaking, thus making them one of the major sources of groundwater contamination in USA. The fate and transport of chemicals from the leaking USTs is estimated from mathematical models. A major difficulty in these modeling efforts has been a crucial lack of information concerning the constitutive relationships governing multiphase contaminant movement.

Centrifugal modeling is an alternative to mathematical modeling, which may give an insight to the problem …