Tikrit Journal of Engineering Sciences

Many studies have been performed in recent years on strengthening RC (reinforced concrete) beams in shear and bending using FRP (Fiber Reinforced Polymer) wraps and laminates. Torsional strengthening, however, has not attracted as much attention. The current study on the torsional strengthening of reinforced concrete beams was performed on reinforced concrete beams wrapped by CFRP (Carbon Fiber Reinforced Polymer). Several different configurations were used for the CFRP and the torque-twist angle paths of the beams were recorded to failure. The failure modes and the increase in the torsional strengths are presented in this paper.

Supervisory Control and Data Acquisition (SCADA) systems have been widely used in industry applications. This paper describes design and implementation low-cost universal serial bus (USB) Data Acquisition (DAQ) which connected with computer through USB port and tested in SCADA system, the designed Data Acquisition build using new generation of microcontroller peripheral interface control PIC18F4550 which supported with USB module and it programmed in C-Language, the developed DAQ have 13 input analog channels and 16 digital I/O lines. At personal computer (PC) side, graphical user interface (GUI) application is designed using Laboratory Virtual Instrument Engineering Workbench (LabVIEW) program as SCADA software to acquire and monitor data and control all system I/O. The system consists of hardware part and software part. The main part of hardware is a data acquisition card, and the software part includes data acquisition card control procedures and PC software. The system hardware developed is a low-cost alternative to commercially available systems that use USB controllers. The work has been implemented for temperature sensing and controlling and the results shown currently support the hardware and software developed. It can be used for biomedical analysis, industrial temperature loggers, industrial process, instrumentation controls and in SCADA system.

In this work, an optimization framework is used to obtain useful model for an ammonia synthesis reactor that can be confidently applied to reactor design, operation and control. The main objective in the optimal design of such reactor is the estimation of the optimal reactor length for obtaining the maximum profit from the reactor at the best top temperature with satisfying the process constraints. gPROMS package has been used for modelling, simulation and optimal design via optimization. The optimization problem is posed as a Non-Linear Programming (NLP) problem and is solved using a Successive Quadratic Programming (SQP) method. New results are obtained for reactor length and optimal cost of the reactor. The effect of various top temperatures on the reactor performance is investigated and the simulation of ammonia reactor at each top temperature that provides further insight of the process has also been presented.

A ten steel-concrete composite beams subdivided into five groups formed from standard steel section (W4X13) connected to concrete slab are designed and constructed using three different types of mechanical shear connectors. A stud connector and regular circular hole perfobond connectors are used in addition to a newly suggested type of triangular hole perfobond connector. The beams are experimentally tested using two-point load beam test to investigate the effect of connector’s type on beam resistance at yielding and ultimate stages. The tests also investigate the deflection at mid-span and slip at the ends of the tested beams. It is found that the composite beams with perfobond connectors can develop a strength higher than those obtained with stud connectors, as well as the newly suggested triangular perfobond connector gives strength higher than the regular circular perfobond. Results also show that continuous distribution of perfobond connectors gives resistance more than those with separated perfobond connectors.

Underground power cables are usually used to transfer electric power from distribution stations to the consumer, especially in densely populated areas in which the overhead lines cannot be used. During the process of energy transfer occurring some phenomena such as high temperature of the cable as a result of the losses, as well as the formation of electromagnetic fields around the cable. The aim of this research is to investigate the levels of electromagnetic fields generated by 11kv underground power cable. Research has been conducted in two ways, mathematical calculations and practical measurements. Results show that the mathematical calculations and practical measurements are approximately identical. The safe and unsafe zones from the underground power cable have been determined by comparison of these results with reference values established by the World Health Organization. These results may consider as an important data for the categorization of underground distribution power cables as well as individual sources of EMF to reduce exposure to such fields in order to avoid its negative health effects on human health.

Water quality degradation in the Tigris River would occur in the last two decades since pollutant loads from agriculture drainages, municipal wastewaters, and industrial wastewaters are not envisaged to be handled effectively. This will face the problems of water quality status which is used for multiple purposes, and drinking is one of these. This study used the Bhargava Water Quality Index (WQI) method as a tool to assess the water quality status of Tigris River as a source of raw water for water treatment plants within Salah-Alddin Province. For this purpose, six sectors along the mainstream were chosen to take water samples from January 2010 until December 2010. The study had shown that the stream WQI lies between 2nd class (good -84.31) to 5th class (poor – 39.73). Decline of WQI values had appeared in all sectors in (January and February 2010) and improved after February 2010. The median values of WQI for Balad sector were the lowest in comparison with other sectors due to the effect of human, animal and agricultural activities, whereas, the median values of WQI for Al-dour sector was the highest because the strong hydraulic mix in addition to high water velocity.

This paper presents the results of laboratory model tests of bearing pressure of circular and ring footing on sand. The effects of the embedment depth, internal friction of sand and the ratio of the inner to the outer diameter of the ring footing have been studied, in order to understand the behavior of the sand under the ring footing comparing with the circular one. An optimum ratio of the inner to outer diameter of the ring footing have been indicated which was (0.4), at which the bearing capacity will be greater than the circular footing. Also, the results indicated that there was no interested effect of the embedment depth on that optimum ratio.

In steam power plants, and high pressure high temperature water flow, phase change takes place resulting in bubbly flow. Such flow causes vibration and noise in the conduits. The present study emphasized on cavitations during a dual phase flow (water-vapor) with a variation of velocities at different conditions in converge-divergence nozzle. The investigation was carried out experimentally and numerically, by CFD simulation. A transparent material is used of PMMA in order to visualize the various regions of the flow. Furthermore, the effect of flow velocities on vibration and noise was evolved in the experimental measurements. The CFD simulation model of this problem is defining a dual compressible viscous flow with k-epsilon model for the turbulence modeling. The analyses of the simulation results and the experimental observation have been seen to be comparatively conscionable in the cavitation zone and the estimation of the throat pressure cavitations during a dual phase flow with a variation of mass transfer conditions. A model were combined with a linear viscous turbulent model for the mixed fluids in the computational fluid dynamics software. A CFD Code with modified user intervention is used to simulate steady cavitation. Some of the models were also tested using a three dimensional CFD code in configurations of cavitation on three-dimensional a converge-diverge sections. The pressure distributions and volume fractions of vapor at different cavitation numbers were simulated, which agreed well with experimental data.

There is a need for development of alternative materials for the building industry with low carbon footprint and at the same time saving energy. Clay has been used as a building material from the beginning of humankind. The Compressed Earth Blocks often referred to simply as CEB, is a type of manufactured construction material formed by the compression of the soil in a mold with the help of a manual or motorized press to form a regular block of appropriate shape and size. For the purpose of researches, the press is manufactured locally at Mosul Technical Institute. In the present work, the effect of semi-hydrate gypsum as stabilizer on some of the mechanical and physical properties of unfired CEB was determined. A series of test blocks were fabricated using a local soil stabilized with 0, 5, 10, 15, 20 and 25% semi-hydrate gypsum, for each of the precedent ratios, three percentages of mixing water were used 10, 20 and 30%, and compacted with a manual press. Results for compressive strength, flexural strength, water absorption and drying shrinkage are presented in the paper. Results show that the addition of semi-hydrate gypsum improves the mechanical and physical properties of CEB. These preliminary results reinforce their suitability for application in low cost buildings.

In this study, the behavior of square footing on gypsum soil is studied under inclined and eccentric loads via fabrication of a simulator of square footing (100 mm * 100 mm), fabrication of load tester and putting the soil in a box having a dimension of (900 mm * 900 mm * 600 mm). A sample of soil is taken from Tikrit University in Salah Al-Din province under 3 m depth which has a gypsum content of (50.48 %). The load test is performed on square footing at eccentricity of (e/B= 0, 0.1, 0.2 and 0.3) and an angle of inclination of the impacted load with the column ( i= 0°, 5°, 10°, 15°and 20°). The local specifications of the soil are measured (density, moisture, maximum density and ideal moisture), it is found that that the vertical falling, horizontal displacement, and base inclination increases with the increasing of eccentricity and inclination of impacted load, the soil resistance is less than the theoretical results for previous researchers in vertical load whereas it is approaching the theoretical results in inclined load. It is also observed that soil resistance decreases with the increasing of eccentricity of impacted load at local density and humidity, whereas it approaches the theoretical results at maximum density, ideal moisture, and vertical load conditions and gives results higher than that of theoretical analysis in inclined load where it decreases with increasing the eccentricity of impacted load. It is found that a high settlement occur in footing when a water (unsaturated with gypsum salts) diffuses through the soil, then gypsum become soluble thereby the soil resistance decreases because of rupturing of chemical bond between gypsum and soil.

Groundwater is considered one of the important water resources in the world. Due to rain shortage and the decrease of Tigris river discharge in the last years, wells excavation and groundwater use for different purposes had been increased without any planning. Therefore, it is necessary to conduct the studies about groundwater quality in Ninevah governorate and define its suitability uses. Additionally, to identify the levels of some trace elements in it, twenty seven wells recently excavated were selected in the study area located south-east Mosul city of about an area of 1500km2. These wells were located in rural and urban areas of various activities: agricultural, industrial and residential. Water samples were collected each two months starting at December 2008 till June 2009. Physical tests were conducted including total dissolved solids, electrical conductivity, as well chemical tests, which include pH, total hardness, positive ions: calcium, magnesium, sodium, potassium, and negative ions: sulfates, nitrates, chlorides, in addition to some of trace element: lead, cadmium, zinc and copper using standard methods for water examination. The geological formation and stratigraphy of the area were described. The right side wells are located within Fatha formation while left side wells are located within Injana formation. Water quality data were statistically analyzed and the results showed significant difference among the wells for all the parameters. These are attributed to the variations geological formations within the study area between Fatha formation which contains gypsum and calcite which has the ability to dissolve in water, while Injana formation contains less amounts of such rocks. Three dimensions contour maps were drawn for water quality parameters and wells coordinate. They showed a clear view for water quality distribution in the area which can be a guide in the excavation of wells of better water quality.

As for maintenance important role had to be take practical measures to implement the maintenance work to ensure all the way continuing operations efficiently and prevent interruptions sudden and at the lowest possible cost, for the purpose of achieving this goal must adopt sophisticated methods guarantee us the perfect application for maintenance work and that the manner in Quality Management. In this research study the reality of the Division maintenance at the university (how the assignment of work, administrative structure, how the decision-making, documentation, …. etc.) and through theoretical study of quality management and maintenance and through field visits and interviews and look at how Division maintenance was reached a new administrative regime can be applied to achieve better performance through conversion administrative system from the Division of maintenance to the maintenance department and the distribution of tasks and the establishment of unit quality and other units new help to organize and develop the performance and was also preparing form is used to adjust the cost of the stomach and form to adjust training methods workers, have also been preparing a flowchart illustrates the stages of decision-making starts identifying the problem and ending the assessment of the resolution and corrected in case of an error.