Tikrit Journal of Engineering Sciences

The effect of initial dry unit weight and type of soil on water and nitrate migration through saturated-unsaturated soil is experimentally investigated using laboratory one-dimensional model (40 mm diameter, 100 mm height) under various head boundary. The results were compared with the numerical results by using packages of finite element name SEEPW and CTRAN of GEOSLOPE software.
The results show that the initial dry unit weight has a significant effect on the transport process of water and contaminant through saturated-unsaturated soils, Nitrate concentration more sensitive than water flow to change in initial dry unit weight due to variation in mechanical dispersion that affected by porosity and void ratio which depended on dry unit weight of soil. Water content and nitrate concentration was highly affected by soil type and water application boundary conditions.

In the present work the relationship between the microstructure and the hardness of the Steel both with and without an addition of niobium was studied. Investigation by direct observation using optical microscopy was carried out.
The purpose of this work was to analyze the effects of the low thermomechanical treatment of ausforming on the final microstructure and hardness of steel and of the same steel modified with niobium.
It was found that the deformation during low thermomechamical treatment of ausforming introduces changes in the microstructure, such as carbide precipitation, which affect the hardness of the steel.
The results show that the mechanical properties of the ausformed Steel depend on the deformation temperature, amount of deformation. The addition of niobium lead to change in the hardness of the Steels investigated.

New medical devices such as surgery devices, physiotherapy devices, cosmetological devices and Magnetic Resonance Imaging (MRI) systems generate a complex electromagnetic fields, so they consider as a potential hazard for medical personnel during surgical procedures. The aim of this research is to detect the EMFs emitted from medical devices and determine the safety ranges from these devices which emit EMF radiations in order to protect Medical staff from its risks. The research has been performed in two parts, numerical calculation and practical measurement. Practical measurements are done in Dijlah hospital at Tikrit city. Obtaining results shows that the practical measurements are consistent with the mathematical calculation results. Comparison of these results with the safety standard guideline limits shows that they are within the acceptable exposure limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and that means there is no health risk from exposure to these fields if the exposure is for a short and not continued periods and lay within the acceptable limits.

In this research the ability of using porcelinite as coarse aggregate to produce light weight concrete was investigated. The experimental program consists of preparing and testing a mixes to investigate mechanical properties of concrete, with a total of 15 cubes (100×100×100) mm, 30 cylinders (100×200) mm. The tests include compressive strength, splitting tensile strength, fresh and hardened density of light weight concrete for different porcelinite percentages ranged between(0% to 100%) of the coarse aggregate weight. The obtained results for tested specimens were compared to control one. Test results indicated that using of porcelinite in concrete mix reduces the strength of concrete Porcelinite aggregate represents a reduction in density ranging between (10%-36%) of normal weight concrete, therefore there is an advantage using this type of light weight aggregate in this country where soil bearing capacity is low in most construction sites.

In this article, multi-input multi-output (MIMO) linear model predictive controller (LMPC) based on state space model and nonlinear model predictive controller based on neural network (NNMPC) are applied on a continuous stirred tank reactor (CSTR). The idea is to have a good control system that will be able to give optimal performance, reject high load disturbance, and track set point change. In order to study the performance of the two model predictive controllers, MIMO Proportional-Integral-Derivative controller (PID) strategy is used as benchmark. The LMPC, NNMPC, and PID strategies are used for controlling the residual concentration (CA) and reactor temperature (T). NNMPC control shows a superior performance over the LMPC and PID controllers by presenting a smaller overshoot and shorter settling time.

An experimental investigation was carried out to study thermally developing fully developed laminar forced convection in a horizontal equilateral triangular channel where the channel surface was heated uniformly. The channel length was (1.5 m) long and constructed from three plane (100 mm) walls to form the equilateral triangular cross section. The experiments were conducted for three mass flow rates (1.91×10-3, 2.54×10- 3 and 3.03×10-3 kg/s) and four heat fluxes (91, 171, 272 and 406 W/m2). Reynolds number range was (1198  Re 1988). It was found that local Nusselt number increasing as the heat fluxes and the mass flow rate increased. Also it was found that the greatest local Nusselt number value was in the beginning of the channel then it decreased accompanied by growing the thermal boundary layer along the channel. Present experimental results have a good agreement with previous results obtained for similarlyconfigured channels.

This paper investigates the effect of steel and polypropylene fibers on static behavior of simply supported deep beams of normal concrete strength under patch loading. Also the paper studied the effect of web opening and its positions on shear capacity and mode of failures for steel fiber concrete deep beams under the same conditions of loading and strength.
Sixteen beams of (1000*300*100mm), eighteen cubes (150*150*150mm) and thirty cylinders (150*300mm) in dimensions were cast with different fiber volume content (0, 0.4, 0.64 and 0.89%) as additives. Shear capacity, mode of failure and three of mechanical strengths were tested.
After testing, the results indicate that shear capacity increases with increasing volume of steel fiber content with change on mode of failure while midspan displacement decreases.

The aim of this research is to design a multi-job control system for controlling on different job on home or office by using a simple scientific technique. Making more holes on walls of home to connect a wire or control cable for any job does not desired.
The research is aiming to design a wireless control system. This control system can send any command to any device in the home or office without making any more holes in walls.
This research depends on using the 220 VAC 50 Hz wires, which had been provided in home or office. The frequencies used to control the devices will be carried by the 50 Hz current used in home. These frequencies have been chosen between 30-110 kHz, and we can use (8) channels in this band to prevent interference of commands. The wireless control on the devices will be done by using a PC computer and simple BASIC program. ON-OFF command can be sent by the operator to any device by a transmitter built and interface with that compute.

This study focused on the behavior of concrete when EM1 was added, to achieve the objective of this study a practical work was done on many concrete mixes. EM1 was added as weight percentage from cement weight (0%, 3%, 6.5%, 10%). The mixes was casted as cubic and cylinders samples and tested after 7, 14 and 28 days. Water cement ratio, compression strength, tensile strength, plastic index and wet density of hardened concrete were computed. The results shows that EM1 increases the workability of concrete compare with reference mixes so EM1 can used to increase the plastic of concrete and increase the compression and tensile and concrete density.

The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion resistance of the normalised steel is in-between them. Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time.

In this research an experimental study was carried out to show the effect of time of
opening and closing the solenoid valve on the effectiveness of finned cross flow heat
exchanger, which has changed the time of opening and closing the solenoid valve (2, 4,
6 sec.) with change the mass flow rate of water each time and the range values between
(0.027-0.0816 kg/s) with constant of mass flow rate of air at (0.032 kg/s).
The results obtained from experiment works that the decreasing in the time of opening
and closing the solenoid valve from (6 sec.) to (2 sec.) leads to increase internal heat
transfer coefficient (hi) the highest increase was by (18.37%) at mass flow rate of water
(0.027 kg/s) and increase the overall heat transfer coefficient (U) and the highest
percentage of increase (7.36%) at mass flow rate of water (0.027 kg/s).
The experimental results obtained show that the increasing both the number of units
transmitted (NTU) and effectiveness of the finned heat exchanger when decrease the
time of opening and closing the solenoid valve from (6 sec.) to (2 sec.) and the highest
percentage of the increase occurring is (8.4%) and (1.74%) respectively at mass flow
rate of water (0.027 kg/s).

In this research work the morphologic and bed material characteristic for 21 km of Tigris River at Mosul city were studied. Seventy seven cross sections were established on this reach. These cross sections were surveyed. Water surface levels were measured at each section and samples of surface and subsurface of bed material were collected. The concentration of the suspended loads was measured at different time periods.
The results show that the river at the studied reach have a different morphology and includes three different shapes (meander part, braided part and straight part), also the rivers contents different bars. The sinuosity of river was 1.3 and bed slope was equal to 5*10-4, the deepest part was extending beside the right bank from upstream of Ninevah Bridge to downstream of Al-Horriya Bridge. The bed of Tigris River at the studied reach is distinguished in two layers surface and subsurface The D50 of these layers was equal to 32 mm and 13 mm respectively .The river bed are approached the armoring condition. The surface bed material particles have mainly a disc shape ,then blade, spherical, cylindrical with percentage 50%, 20%, 18% and 12% respectively.. The concentration of suspended load was in rage of 6-30ppm during the whole year except the rain fall periods where the suspended concentration may increased over 3000ppm.