Tikrit Journal of Engineering Sciences

An investigation was carried out to determine the corrosion rate of carbon steel (A 106 Grade B) as flow line in crude oil production with CO2 content employing three Iraqi crude oil (Kirkuk crude oil, Halfaya crude oil, and Rumalia crude oil) with identical produced water (brine) [1%NaCl, 2%NaCl, and 3%NaCl]. Experiments were performed in an autoclave test apparatus, crude oil-produced water mixtures, water cuts were (0, 10, 20, 30, 40, and 100%), and temperature (20, 40, 60°C). For all experiments, CO2 partial pressure was maintained at 4bar and rotational speed 500 rpm. The corrosion rates were determined by the weight loss method. The results revealed that the corrosion rate of carbon steel increased by increasing water cut and temperature, but decreased with increasing salt concentration for all types of crude oil. Rumaila crude oil exhibited the highest corrosion rate and Kirkuk crude oil exhibits the lowest corrosion rate while Halfaya crude oil exhibits a moderate corrosion rate.

Copper -graphite composites are widely used in a great number of engineering applications such as brushes, switches, sliding bearings, self-lubricating bearings, etc. due to their good thermal and electrical conductivity and excellent tribological properties as compared with other structural materials. There are ongoing attempts in manufacturing copper composites with better properties to enhance their efficiency and increase their effective life. Present research aims to prepare hybrid 95wt.% copper –5wt.% graphite composites reinforced with yttria and tin particles by powder metallurgy technique and to study their effects on mechanical and physical properties of the prepared composites. Powder mixture was mixed by ball mill mixer at 100rpm for 120min with (5/1) balls to powder ratio. The powder mixture was cold pressed at 700MPa for 30sec, followed by sintering at 900 ˚C for one hour. In the first stage, Yttria(Y2O3) was added with (2, 4, 6, 8, 10) wt% to pure copper (Cu) and to (95%Cu-5%Gr) matrices. Typical composite of this stage was ((95%Cu-5%Gr)-4%Y2O3. In the second stage, tin (Sn) was added with (2, 4, 6, 8, 10) wt% to pure copper and((95%Cu-5%Gr)-4%Y2O3 matrices. Typical composite of this stage was ((95%Cu-5%Gr)-4%Y2O3)-6%Sn. The results showed that hardness and true porosity of the composites increases with increasing yttria content. On the other hand, both thermal and electrical conductivity of the composites decreases with increasing yttria content. It was also found that (95 wt.% Cu- 5 wt.% Gr) – Y2O3 composites have always lower wear rate than plain Cu-Y2O3 composites.

The present study attempts to represent the behavior of shallow foundations under the effect of eccentric inclined loading in terms of the main criteria of design which are the ultimate bearing capacity, permissible settlement, horizontal displacement and tilt. Due to the square shape of the analysed foundations, three dimensional finite element analysis are used. Elastic-perfectly plastic behavior of soil and rigid of foundations was adopted using Mohr-Coulomb criterion, 15-Node wedge elements were used to model and represent the soil and 5-Node linear elements with three degree of freedom to model and represent the foundations in used program PLAXIS 3D TUNNEL version 1.2.The results of analysis were presented in the form of pressure-settlement, pressure-horizontal displacement and pressure-tilt characteristics. Then the ultimate bearing capacity of the foundations were gotten and compared with (Meyerhof, 1956) and (Saran & Agrawal, 1991), a good agreement was found between them. Using the data obtained from the analysis, non-dimensional correlations have been developed for predicting the values of settlement, horizontal displacement and tilt of eccentrically-obliquely loaded foundations. These relationships can be used by the engineers.

Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2 and ZnO, with different volume fractions in range of 1-4% and different nanoparticles diameter in the range of 20 – 80nm in base fluid (water) were used. Numerical investigations are conducted using finite volume method. In this study, different parameters such as the geometrical specifications (different steps heights in the range of h1= 0.01m-0.04m and h2 = 0.03m-0.06m for FFS) are used. Different Reynolds numbers in the range of 50-2000 (laminar flow) are investigated to identify their effects on the heat transfer and fluid characteristics. The results indicate that SiO2-water has the highest Nusselt number followed by Al2O3-water,
Cuo-water and ZnO-water. The Nusselt number increases as the volume fraction increases but it decreases as the nanoparticles diameter increases. The velocity magnitude increases as the density of nanofluids decreases. The recirculation region and the Nusselt number increase as the step height, Reynolds number, and the volume fraction increase.

The modern evaluation and analysis techniques for the horizontal deformation of concrete structures such as barrages depend on a geodetic network, with control points, required to carry out the adjustment for the networks according to the adjustment techniques "Least Squares method". The study included measurement of fourteen point in the downstream side, depending on the global satellite navigation system and using the Adjust program to calculate the amount of displacement resulting. A comparison done between the resulted deformations magnitude for the network points for 2014 epoch with respect to the General Directorate for Survey (GDS) at epoch 2005 the deformation or movement could be verified by applying the statistical techniques to analyze the movement. The analysis shows that the movement displacement systems stable and amount 3.5cm.

This paper describes a modern approach for the protection of transmission lines to ensure their safety against the faults occurred in power systems. Our approach uses a Programmable Logic Controller (PLC) to realize a transmission line as an over current protection relay. A conditioning circuit was designed, implemented and tested to collect data obtained from Hall Effect sensors which convert them to suitable analog values compatible with PLC's inputs. Results obtained by our PLC control system are very similar to those obtained by the conventional relays but more efficient. An Automatic Reclosing System (ARS) for remote faults is also included in this approach. Our PLC control system and its algorithm are illustrated in this paper also. This approach is designed to be used in electrical networks laboratories as an educational unit in electrical departments of engineering collages and technical institutes; it can be used also in real power systems through suitable interfacing facilities.

This study investigates the "bearing capacity" of a strip footing subjected to inclined and "eccentric load" on geogrid reinforced sandy soil by using physical modeling. The effect of each of the "depth ratio" of the first sheet of reinforcement, the vertical space ratio between consecutive sheets, number of reinforcement sheets, and the effective "depth ratio" of reinforcement on the "bearing capacity" were investigated. Also, the combined effect of load inclination angle, eccentricity ratio of the load and the relative density on the ultimate "bearing capacity" were studied. The results illustrated that by increasing the number of reinforcement sheets, the "bearing capacity" increased, but there is an optimum value (4-5). The optimum "depth ratio" of the first sheet of reinforcement was 0.35B. The optimum vertical space ratio between consecutive sheets was 0.25B. Using a test results with helping a statically analysis software program, a new easy and reliable empirical equation for computing the ultimate "bearing capacity" of the strip footing subject to inclined and eccentric load supported on geogrid reinforced sandy soil was developed.

Finite element method with a computer program SEEP/W were utilized to determine the "quantity" of flow through homogeneous earth dams with triangular toe filter. The effect of angle of upstream slope, angle of downstream slope, angle of toe filter, height of dam, crest width of dam, free board, length of toe filter and coefficient of permeability on the quantity of seepage were studied. The results show that, the seepage quantity decreased with increasing angle of toe filter, free board height and crest width of dam. Also, from the results can be concluded that, the flow quantity increased with increasing angle of "upstream slope", angle of "downstream slope" and length of toe filter. Using statistical analysis by a SPSS-19 program, a new empirical equation was suggested to estimate the quantity of seepage through earth dams with triangular toe filter.

Although it is difficult to imagine life without electricity, there are compiling confirmations show that exposure to magnetic fields correlated electricity and radio frequencies pose magnificent hazards to human health. The most economist method to transfer electricity from power generation stations to users is by measures of high power transmission lines, buoyed by big transmission towers. The cables laced between the towers radiate magnetic and electric fields. In this research study, the magnetic field at ground level under 400 kV network lines extended in residential places have been conducted in two ways, mathematical calculation and practical measurement then the obtained results analyzed and compared with the international standards reference values. the reason of chose this type of transmission line is frequently using. The results indicate that they fall within the safe limiter commended by the World Health Organization. the strength of radiation increasing with high of sea level and moisture ratio because of air ionization

The aim of this paper is to determine the performance of the heat exchanger system using the hydraulic fluid . Investigation of heat exchanger system efficiency has been done versus the flow rate on the BETA test loop. This system can be used for investigation the hydraulic thermal changing. The Sequences on this system consist of a heat exchanger circuit that serves as a heat degree reducing from the primary part to the secondary part .The test method is carried out by operating the heat exchanger system with some variations of fluid flow rate in the primary part. The efficiency of system has been determined by comparing the energy value in the primary inlet to the energy value taken out form outlet by a secondary. Obtained results indicates that the increasing of fluid flow rate in the primary part from 3.86x10-4 m3 /s to 8.23x10-4 m3 /s cause a reduction in the efficiency of the heat exchanger system of about 82% to 74%.

Waste food residues are considered as suitable raw materials for the production of low cost adsorbents. In this work, activated carbons was perpetrating from household waste food (orange peels, banana peels, walnut shells, olive stones and their mixture). Chemical carbonization at 500˚C for 1.5hr was used to prepare carbons and their activation by KOH and CaCl2 solutions for 24h. Then added 0.1g of activated carbons to the solution of blue dye prepared laboratory to demonstrate the activation of the types of activated carbons prepared to remove the blue dye. The results indicated that characteristics (yield, burn off, density, moisture content, ash content, pore volume, porosity percent, Iodine number, methyl blue number and removal percent of methyl blue) for all activated carbons were compared with commercial activated carbon. It has been found that activated carbon from orange peels and mixtures activated with CaCl2 had the best adsorption properties reach to the (80, 77.5) % removal blue dye respectively and iodine numbers (741, 735) mg/g . This low coast activated carbons can be used for wastewater treatment.

This work aimed to analyze and evaluate the metrological draught in Iraq. Monthly rainfall data were collected from 22 meteorological stations scattered all over Iraq for the period 1970-2010. Various statistical tests have been performed to examine the data accuracy, e.g. Consistency test, Trend analysis, as well as homogeneity test. The Standard Precipitation Index (SPI) and Theory of Runs are used to analyze the metrological draught and evaluating the draught characteristics. SPI values have been estimated for 12-month time scale, from January to December. To analyze the drought characteristics, the accumulative deficit, drought duration and intensity for each station have been estimated. The results showed that the rainfall data series considered in the study are all consistent with negative trends except Hilla station, random except Haditha and Samawah stations and homogeneous. It was shown that the study area has been suffered from sequent drought events through nearly half of the years considered in the study, and the worst were in 1997-2001 and 2007-2010 in which extreme droughts were dominated several parts of study area.