Tikrit Journal of Engineering Sciences

This paper deals with the linear elastic behavior of thick circular plates on Winkler type elastic foundations with both compressional and tangential resistances. The finite element method with different isoparametric thick plate and brick finite elements are used to solve problems, which were previously solved by the finite difference method. Good agreement was noticed between the different methods

In this study, the behaviour of shallow foundations near slopes is studied using nonlinear elastic finite element analysis. Forty-four cases of strip footings resting on cohesionless soils that were studied by Sud (1984)[1] through model tests, have been analyzed. Pressure-settlement relations has been compared with experimental results of (Sud, 1984) [1], and a good agreement between the two has been observed. Ultimate bearing capacity of shallow foundations near slopes was evaluated using the intersection of two tangents of pressure-settlement curve. The values of ultimate bearing capacity agree well also with (Sud, 1984) [1]. A non-dimensional correlation has been developed between the settlement of footing erected near slope (Sβ) and the settlement of footing resting on level ground (So). The relationship (Sβ/So versus De/B) can be expressed by a unique relation for different slope angles (β). This relation has been found to be dependent on distance of the edge of the footing from slope shoulder; De, and angle of slope; β, while it is independent of the relative density of sand; DR, and the factor of safety. By knowing the settlement of a footing resting on a level ground, the settlement of a footing erected near slope can be evaluated using this correlation.

A non-linear finite element method for elastic – plastic analysis of steel plane frames under sudden loading is investigated. Geometric nonlinearity is considered using the Adaptively Shifted Integration (ASI) technique for the linear Timoshenko beam element.In (ASI) technique, the numerical integration point in an elastically deformed element is placed at the optimal point for linear analysis (midpoint in the linear Timoshenko beam), while the integration point is shifted immediately after the occurrence of a fully-plastic section in the element, using the previously established relation between the location of numerical integration point and that of plastic hinge, to form a plastic hinge exactly at the position of that section. Thus the technique produces higher computational accuracy with fewer elements than the conventional finite element code. As a result, the ASI technique gives a more precise solution with fewer elements than the conventional finite element method. The computer program used in this search employs the one –dimensional element with two nodes for steel structures. The major task of the present work is the development of a computer program which incorporates the above method of analysis, and the accuracy of the analytical results is assessed with respect to the available experimental and analytical data.

Bubbles coalescence frequency and the transition concentration in a dispersion column were studied experimentally by using ethanol-water mixture as a liquid phase and air as a gas phase. The study was devoted to express the effect of the liquid properties on the performance of the dispersion column, and the experimental work was designed for this purpose, where the range of weight percent of ethanol in water, (0.1-0.7) Wt%, and the range of superficial gas velocity of air, (2.5-30) mm/s. The experimental runs were planned using the central composite routable design method. The experimental data obtained agreed quite well with a polynomial type of correlations by using computer program. The experimental data shows that the values of bubble coalescence decrease with increasing superficial gas velocity of air, and ethanol transition concentration was successfully correlated as a function of the superficial gas velocity of air,


ct= 0.158214 − 0.010849Ug + 0.00045Ug2 − 0.000008Ug3 . This equation gives mean deviation of 10.393%.

Results are presented from a series of laboratory experiments conducted on an open channel. Twenty five data sets (L1-L25) have been measured to obtain the magnitude of the longitudinal dispersion coefficient and eight data sets (T1-T8) have been performed to estimate transverse mixing coefficient in channel. The method involves derivation of a new expression for the longitudinal and transverse dispersion coefficients which used routing concentration of pollutant in the advection- dispersion equation solution in water quality mathematical model. Values of longitudinal and transverse dispersion coefficients are compared with measured data and previous similar studies. These comparisons have been showed that tracer technique by using second moment is the most accurate prediction of the longitudinal and transverse dispersions coefficients than the other techniques.

In the present study, modified relations were obtained to relate rainfall intensity with frequency using Weibull method for 15, 30 and 60 minutes duration. This was done to estimate the designed value for rainfall intensity for any mentioned duration at any observation interval. The obtained results show that the rainfall intensity increases with the increasing of return period. Also, for every duration rainfall, the intensity decreases with the increasing of duration. Two types of probability distribution tests were applied for any duration, they are Gumble and Person (III) tests, also, statistical tests were applied to determine the optimum and suitable distribution for the studied data. The obtained relations can be usefull as a design equation for small weirs, culverts and rain downsrtream systems in the case of construction of them in the studied area.

This research concerned with theoretical and experimental study of forced convection through circular cross section channel that is horizontally arranged and heated under constant heat flux. The theoretical part delt with numerical solution for momentum equation of one dimension and energy equation of tow dimension by used of finite difference at variable grid size in vertical direction at gradient pressure between (103-106) The energy equation used implicit method and marching process to find the value and distribution of temperature through this channel. This model have been compared with another that have variable permeability and porosity and show that the change in permeability and channeling phenomena have significant effect on increase of rate of heat transfer and also increase in Nusselt number to 30% and also show show that the increase in gradient pressure is variant with rate of heat transfer ,but this variant disappear in thermal fully develop region. In experimental part testes was carried out for three value of Peclet numbers (17,25,40) with change of amount of power supply for each number. The results show hat the increase rate of heat transfer cause increase of Nusselt number and also show good agreement between theoretical and experimental results especially at low Nusselt number and also show there is deviation of experiential result from the theoretical result at high Nusselt number about 20%.

It is planned for this research to build a simulation computer program aimed to optimum design of shell and tube heat exchanger according to thermal operation conditions. The optimum thermal design requires entering a preliminary dimensions for heat exchanger configuration, and it is controlled by the program to fit the design condition for hydraulic flow. The program includes testing different types of shell and tube heat exchanger to enable the designer from choosing suitable replacement for thermal operation conditions, It also show the effects of the operational conditions such as velocity and pressure drop on the heat transfer process and hydraulic flow for these types of heat exchangers to forfeit the design range of these conditions. The concluded results of the program for the heat exchangers dimensions with the standard specifications of the tubular exchanger manufacturers association (TEMA) showed a good agreement with percentage error not exceeding (4%).

Phosphate and nitrogen compounds considered as an important pollutions that due to feed lakes and slow motion river with algae . hospital effluents considered as a sample for study because it have high rate of nutrients, the paper used two reactor ,the first working under batch system ,the second working under sequencing batch system during circle time of 24 hr for the both reactor.The study made comparison between two reactor on the removal efficiency of phosphate and nitrogen compounds. The results have shown that phosphate removal in sequencing batch reactor(SBR) more than its removal in batch reactor .The heights value of removal achieved after 12hr of reaction in sequencing batch reactor (SBR) .The removal efficiency was between (40-82)% and its between (20- 62)% in batch reactor .Ammonia removal increased as organic load decreased and the removal efficiency increased in sequencing batch system . The heights value of removal achieved after 16 hr of reaction and its approximately substantiate. The removal efficiency of ammonia in (SBR) was between (96-98)%and its between (90- 95)% in batch reactor. The nitrate removal happened only at sedimentation time at the end of reaction in batch reactor but in (SBR) Anoxic condition assisted on the removal of nitrate and its due to rise the pH value of effluents.

An experimental and numerical study conducted on mixed convection through porous medium between inclined two plates , heated from below and cooled from top, an experimental contains manufacturing device and connecting thermocouples then reading temperatures for every thermocouple with inlet air velocity in the range : 5