Tikrit Journal of Engineering Sciences

Groundwater is the greatest significant source of water in the Bahr Al-Najaf area. In this research the DRASTIC technique has been utilized, to produce a map of ground water vulnerability for the area. Because of the relation between LULC (Land Use and Land Cover) and groundwater pollution, the LULC map was applied with the standard DRASTIC technique to confirm accuracy of vulnerability for pollution. A LULC map is extracted from Enhanced Thematic Mapper (TM) satellite imagery utilizing several methods in GIS. The LULC map shows that three portions of LULC can be recognized (Agricultural land, Wet land and Barren land). The LULC map was weighted and rated then changed to LULC index map. That index map is a supplementary factor that was combined to the standard DRASTIC technique to modify DRASTIC vulnerability in study area. The final vulnerability was obtained by the DRASTIC technique that varies from (70 to 140). The LULC index map as a modified DRASTIC with ranging of (95-175). The modified LULC of DRASTIC technique has a higher correlation (Pearson’s factor) 0.87 per concentration of nitrate values and is suggested as the best suitable technique to be utilized for the area of study.

This paper studies the performance of a proposed desiccant assisted air conditioning system operating under the hot and dry climate conditions of Mosul city, Iraq. The proposed system consists of three stages: indirect/direct evaporative cooler, an enthalpy wheel, and a traditional vapor compression system. The performance of the suggested system is compared with that of the vapor compression system operating at the same conditions. The simulation results showed that an optimum rotational speed of 12.5 rpm is required for the enthalpy wheel to achieve the best system performance. The simulation results also showed the ability of the proposed system to achieve a power consumption saving of 51.03%, in the ventilation mode, and 22.93%, in the mixing mode with a ventilation mixing ratio of 0.4 when compared to the vapor compression system.

The mole ratio of an acid base reaction is one of the important values to state the stoichiometric relationship between acids and bases. However, solving acid-base problems based on stoichiometry is still challenging for new chemists.This issue renders the use of a model for predicting the volume of the acid used an exciting endeavour in academia. This work was to study the individual and interactive effects of the titration parameters such as acid concentration, base concentration and the number of the indicator drops on the volume of acid used in the titration process, using methyl orange as an indicator.We also aimed to study the central composite design (CCD) model of response surface methodology (RSM) for experimental design and modelling of the process. The experimental data were analysed using analysis of variance (ANOVA) and fitted to a second-order polynomial equation using multiple regression analysis. The regression analysis showed a good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R2) value of 0.9751 and model F-value of 43.37. The response surface and contour plots were generated from RSM tool for the interactive effects of the studied parameters on the volume of acid used. The developed model was further validated using existing acid-base titration problems from the Senior Secondary Certificate Examination (SSCE) past questions over 30 years. All observations indicated that the developed model was only valid for a monobasic acid.

Phenol is one of the most dangerous pollutant of petroleum industry. Thus its removal is very essential. One of the most popular method used to remove phenol is through adsorption by activated carbon. In the present work, batch adsorption experiments are carried out under various operating parameters: pollutant concentration (CO) (10, 30, and 50mg/L), and activated carbon dose (CD) (250-1500mg/1.25L with an increment of 250). All experiments are performed at laboratory temperature (19ºC) and pH of 7 ± 0.1 while a full factorial mode is applied. Many adsorption models are used to fit experimental data and find out adsorption capacity (ADC) which is a widely used term.The results show that phenol can be completely removed and the adsorption capacity depends on the pollutant concentration (CO) and adsorbent dose (CD). The actual adsorption capacity (AADC) is calculated and found to be highly different from adsorption capacity.

In the building process, the recycling of aggregates arising from building and demolition debris is one of the best alternatives to maintain the environment and the areas needed to bury these debris. It also helps to preserve natural concrete sources from depletion efficiently. The use of recycled aggregates in new concrete manufacturing, however, leads to a decrease in concrete's strength characteristics. This reduction rises with the rise in the percentage of recycled aggregates used in concrete, which has caused many researchers to undertake many researches on how to enhance the characteristics of recycled aggregate-containing concrete. This paper presents several studies that examined the effect of adding steel fiber to improve the properties of concrete containing a coarse recycled aggregate.

To investigate and understand the effect of lime on the engineering properties of an expansive clayey soil, 4% lime by weight of the dry soil have been added. The stabilized soil specimens were subjected to unconfined compression, swelling potential and pH value tests. Also, a finite element analyses using PLAXIS-2D software were conducted. The studied parameters include the footing size and thickness of lime stabilized soil, and then compared with the natural soil. It was proved that lime content and curing duration had a significant effect on the engineering properties of lime-treated soil. The curing duration had significantly enhanced the strength properties of the lime stabilized soil specimens, where, unconfined compressive strength has significantly improved. Also, the pH value was decreased with increasing curing durations. Moreover, it was found that the swelling potential of the lime-treated soil specimens was reduced by lime addition and increasing of the curing duration. The results of numerical analysis show that the stress-settlement behaviour and ultimate bearing capacity of footing can be considerably enhanced as the thickness of lime-treated increases, and the influence of footing width seems to be insignificant.

This paper deals with the multivariable control system of the distillation tower by applying multi-structures in MATLAB/Simulink for a binary mixture of benzene and toluene. Four structures configurations of the distillation are applied based on the level and temperature variables. The PID controller is used in all structures in multivariable. These structures are compared with different disturbances. The integral absolute error is a criterion to test the controller's performance under step change disturbances. The controller's performance was investigated by recording responses to disturbances in set-point of reflux ratio, flow-rate of top and bottom products. The step testing appears to be the single-ended temperature control with bottom and top-level structures to regulate the flow rate of the bottom and top products. The best structure is top-level, bottom level and condenser temperature because the column made more stable, the integral absolute error is minimum value and fast access to set-point value.