Tikrit Journal of Engineering Sciences

In the present work, a comparative performance analysis of the gas turbine power plant with and without power augmenting devices was carried out. The intercooler, turbine burner (reheater), and heat exchanger were inserted individually and together to reveal the effect of each device. A model for each addition was derived on the base of the simple cycle and adapted to reflect the effect of the performance parameters on the plant power and thermal efficiency. The heat exchanger with different effectiveness improves the thermal efficiency but for low pressure ratios, while the intercooler has low effect at low pressure ratios. Its effect increases with increasing of this ratio and this needs advanced materials. The intercooler cooling percent was considered as 50%, 75% and 100%. The use of turbine burner alone augments the output power by 19.4% but on the expense of thermal efficiency (dropped by 4%) and fuel price. The interstage compressor cooling augments the power by 1.3%, while the efficiency increases slowly and needs a large amount of compression. The combination of intercooling with turbine burner enhances the power by 13.4%. So the regeneration must be installed with them to ensure an enhancement in plant compatibility and thermal efficiency.

The present work deals with studying the dynamic behavior of a batch distillation column and implemented two types of control strategies for the separation different types of binary systems. The model was derived and then simulated using "MATLAB" program. The experimental data of dynamic behavior were to tune the parameters of PID controller and developed the training of neural networks controller by using supervised learning algorithms. The simulation results show a qualitatively acceptable behavior. This study shows also that the response of PID controller was oscillatory behavior with high offset value while neural network controller gave less offset value and less time to reach the steady state. In general, a good improvement is achieved when the neural network controller is used compared with PID control.

The work in this research presents an experimental, theoretical and field study in order to investigate the settlement of Gypseous soils and the effect of water percolation on collapsibility of this soil. In this research, more than five sites where chosen to extract the gypseous soil samples with different gypsum content; the sites located in different regions in Salah Aldeen Governorate. In order to estimate the settlement and collapse of gypseous soils, field tests consist of standard penetration test for depths (1m to 5m) for each site and plate load test were conducted in dry and soaked cases.
The results show that the settlement of gypseous soils in dry condition is less than the same soils that have low values of gypsum in its formation, the settlement value of lightly gypseous soils can be evaluated from the basic equations depending on data of SPT.
In soaking case with short term flooding, gypseous soils shows compressible and they are sufficiently reliable soil base, while in the case of long term flooding settlement develops due to dissolution of salts and gypsum. The magnitude and the rate of the settlement depend on initial gypsum content, relative amount of leached salts, the mineralogy and type of soil and soil properties and acting load.
The standard penetration test does not use in calculating the settlement for the soils that have gypsum in its formation in soaking condition.

Owing to the energy crisis and pollution problems of today investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using exhaust gas after treatments methods like PM filters and EGR for NOx reduction. In this study, the combustion characteristics of diesel fuel were compared with that produced from adding EGR at several percentages to air manifold. The tests were performed in a four-cylinder direct injection (DI) diesel engine at constant engine speed (1500 rpm) and variable loads (from no load to 86 kN/m2), the tests were repeated with constant load (77 kN/m2) and variable engine speeds (from 1250 to 3000 rpm).
The experimental results showed that adding EGR to diesel engine provided significant reductions in brake power (bp), brake thermal efficiency and exhaust gas temperatures, while high increments in brake specific fuel consumption (bsfc). High EGR percentage (as 30% in this article) caused an 11.7% reduction in brake thermal efficiency, 26.38% reduction in exhaust gas temperatures and 12.28% in volumetric efficiency at full load conditions.

In this research, trial mixes were conducted according to Self-Compacted Concrete (SCC) specifications, a mix that gave a higher compressive strength to the age of seven days has been selected. Then after selecting the appropriate mix, concrete samples had poured and were distributed into five groups; each group consists of six cubes, six cylinders, and six prisms. The samples of each group are testing for compressive, tensile splitting, and flexure strengths respectively for the ages of 7, 14, 28, 60, and 90 days respectively. Before of conduction of destructive tests, the samples were tested using ultrasonic waves to determine the relationship between the concrete strength and pulse velocity and in the same way for all ages in above. Experimental results showed that, all concrete mechanical properties have improved, and the maximum improve was in flexural strength followed by compressive strength and tensile splitting strength. The cube compressive strength increased according to (G1 at 7 days curing) from 34.3% to 71.8%, the percentage of increase of tensile strength according to (G1 at 7 days curing) from 16.8% to 64.3% , modulus of rupture increased according to (G1 at 7 days curing) from 34.6% to 98.7% for ages (14, 28, 60, 90 days) respectively. Pulls velocity increased according to (G1 at 7 days curing): For cube from 5.1% to 23.9%, for cylinder from 21.4% to 40.3%, for prisms from 7.1% to 29.2%.

Gypsum has been used as building material over a very long period of time. The production of gypsum plaster in Iraq confined on three types; plaster of Paris, ordinary gypsum and mechanical gypsum. The purpose of this study is to present a proposal to produce another type of gypsum plaster called Keene's cement, it has improvement characterizes than the other types of gypsum. In this study different percentage of alum solution has been used to soaked in gypsum lumps and different recalcinating temperatures also have been used. The results show that 12% of alum and 250 C° recalcinating temperature gave the highest result of compressive strength of Keene's cement product.

This paper presents a new design for controlling microwave oven (MWO) device which has become used daily in last few years. The aim of this work is to develop the operation of the recent MWOs, where three new features have been proposed to be supplemented to the new design, the first one is adding a load cell under a turntable specified for MWO to measure the weight of the processed food instead of setting it manually. The second feature is incorporating the fuzzy techniques with the design of MWO by designing a fuzzy controller capable to decide the suitable power level and total heating time automatically according to the measured weight. While in the third feature a steam sensor has been suggested to be added in the upper cavity of the MWO, so the controller will be able to decide the remaining time to finish once the presence of a steam is detected. Finally the output results of the controller have been tested practically on some kinds of food using the available MWO. The results proved the efficiency of using this design by finding the suitable parameters to process food without dependence on the repeated estimation by the user.

The maximum power point tracker techniques vary in many aspects as simplicity, digital or analogical implementation, sensor required, convergence speed, range of effectiveness, implementation hardware, popularity, cost and in other aspects. This paper presents in details comparative study between two most popular algorithm technique which is incremental conductance algorithm and perturb and observe algorithm. Two different converters buck and cuk converter use for comparative in this study. Few comparisons such as efficiency, voltage, current and power output for each different combination have been recorded. Multi changes in irradiance, temperature by keeping voltage and current as main sensed parameter been done in the simulation. Matlab simulink tools have been used for performance evaluation on energy point. Simulation will consider different solar irradiance and temperature variations.

In this research, the major problem of mass concrete (Differences in Temperature) was studied. Expanded polystyrene and perlite were added in different percentages to investigate the effects on some mechanical properties and thermal conductivity of concrete. Two stages of work were performed.
In first stage, reference mix was designed at proportion (1cement: 1.41sand: 2.72gravel) with (0.4) water cement ratio. Four tests were conducted, these tests including density, compressive strength, flexural strength and thermal conductivity through exponential equation depending on dry density. In the second stage, polystyrene beads and perlite were added as volumetric ratio with (10, 15, 20, 25, and 30) percentages to the original size of reference mix and conducted the tests and study their effects .The results showed a significant improvement in thermal insulation and reduced thermal conductivity (40 , 22) % by using (30) % of polystyrene and perlite respectively. The decreasing in some mechanical properties can be seen and this decreasing did not have serious effects on the design efficiency of the structure which conformed with the specifications.

A single cylinder variable compression ratio spark ignition engine type PRODIT was used in this study. The experiments were conducted with gasoline fuel (80 octane No.)at equivalence ratio (Ø =1). This study examined the effects of exhaust gas recirculation on emission. It was conducted at engine speeds (1500, 1900, 2300 and 2700 r.p.m.).
The exhaust gases were added in volumetric ratios of 10%, 20% and 30% of the entering air/fuel charge. The results showed that the EGR addition decreases the CO2 concentrations, in the same time CO and HC concentrations increase remarkably. NOx concentration decreased highly with the increase of EGR percentage at variable engine speeds and constant torque. Also, it decreased when the engine run at constant speed and variable engine torque. The exhaust gas temperature decreased with increasing EGR ratio.

The investigations have been concentrated on decreasing fuel consumption by using alternative fuels and on lowering the concentration of toxic components in combustion products. LPG as an alternative to gasoline has emerged as a solution to the deteriorating urban air quality problem, especially in an oil country like Iraq. LPG has already been used as cooking fuel in Iraq. In the present paper practical tests of various operating parameters and concerns have been prepared for better understanding of operating conditions and constrains for a LPG fueled internal combustion engine.
The results show that HUCR for gasoline was 8:1, and for LPG was 10:1. bsfc reduced by using LPG at its HUCR, while at CR=8:1 it became higher than that for gasoline. Volumetric efficiency reduced by using LPG due to its gaseous nature, but it was improved when the engine was run at HUCR. Brake thermal efficiency depends on bsfc and bp, so LPG preceded gasoline at medium speeds and torques. Exhaust gas temperatures reduced by using LPG, the minimum values were when the engine operated at CR= 8:1. The maximum values were for gasoline share.

Tigris River considers the main resource of water for Mosul city, therefore it is of great importance to evaluate its quality continuously. In this study, chemical and physical properties of Tigris River had been studied within Nineveh governorate during the year (2012) by using the average values for ten selected sites. Computing of Water Quality Index (WQI) was done by using Weight Average (WAV) method. In spite of the large amount of the wastewater disposed into the river, the results indicated that Water Quality (WQ) in all the studied sites was suitable for irrigation purposes. For drinking purposes, only the first northern four sites were in need to simple treatment, while the following remaining sites need conventional treatment. The efficiency of the three main Water Treatment Plants (WTPs) on Tigris River were computed according to a new (WQI) that include new additional parameters and different relative weights. These three plants are; Mosul new left side (WTP), Mosul right side monotheist (WTP), and Mosul old left side (WTP). The efficiency results were (07, 62, 55)% respectively. The Low efficiency of the old plant was due to the high effluent concentrations of turbidity, SO4, total hardness, and TDS.