ISSN: 1999-8716

Volume 3, Issue 0

Volume 3, Issue 0, Winter 2010, Page 1-513


THE EFFECT OF HEAT SINK FINS LENGTH ANDMATERIAL ON ITS PERFORMANCE

Ahmed A. Abdul Jabber

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 1-11

ABSTRACT:-In this paper an investigation of five lengths of three different materials (steel, copper and aluminum) of one quadrate type of heat sink (which commonly used in earlier high performance graphic cards of built-in motherboards) to measure its conductivity and ability of emitting heat when the chipset works at its maximum performance (reaches a temperature of nearly 60o C) and to investigate the relationship between the heat sink length ,material and its performance taking cost into consideration. It's known that for emitting heat copper came 1st then aluminum and steel in 3rd place, which conform the results, but if we take cost into consideration the aluminum model takes the lead, the results also shows the effect of fins length upon heat sink ability of dissipation heat and it conclude that an aluminum heat sink of 2 -2.5 cm fins length is the best.
Keywords: Investigation, Heat sink, Fins.

STUDYING AND QUALIFYING THE WELDABILITY OF LOW ALLOY STEEL ASTM A242 BY GAS METAL ARC SPOT WELDING

Basem M. Abed

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 1-16

This research deals with influence of the MIG/MAG spot welding process on the mechanical properties of the spot weldment of low alloy steel (ASTM A242) and the determinations of optimum conditions for the spot welding variables , welding current and time for thickness (2.5,5mm) with shielding gas Ar and Co2 . Results show that the maximum shear force for the spot weldment would increase with increasing of the welding current and time to specific amount, after words the shear force would drop at the higher currents and longer time. For (2.5mm) thickness the maximum shear force was (20.6KN) at welding current (280AMP.) and welding time (5Sec.) for the Co2 shielding gas while for the same thickness with Ar shielding gas the maximum shear force was(22.2KN) at welding current (265AMP.) and welding time (5Sec.). with (5mm) thickness the maximum shear force reached (35.2KN) at welding current (330AMP.) and time (5Sec.) when Co2 shielding was used while for the same thickness with Ar shielding gas the maximum shear force was (37.1KN) at welding current (315AMP.) and welding time (5Sec.)

STATE STRAIN AND DEFORMATION FOR POLYMER COMPOSITE MATERIAL BY USING NUMERICAL SOLUTION

Ahmed Falh Hasan

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 12-25

ABSTRACT:-This study deal with composite materials made of E-glass , carbon fiber with epoxy matrix at volume fraction 0.6 , by using mat lab 2008 a was used to state the deformation and strain in both x,y direction .
40*40 mm element was subjected to tensile stress in x direction with value 200,300,400 and 500 MPa with two angle θ=0 and θ=45 degree, the von miss stress distribution has been stated by using solid work at 400,500 MPa.
The results was showed when θ=0 glass fiber have value of strain more than carbon fibers, when θ=45 carbon fiber have value of strain more than glass fibers .the change in right angle gave us zero indicating when θ=0 ,and θ=45 the change in right angle gave us negative indication .the von miss stress at 500 MPa was low factor of safety .
Keywords:- composite material, mat lab, epoxy, strain, deformation.

STUDY OF CHANGEABLE OF A WORK THE ALLERGIES SENSORS IN ENGINE OF VEHICLE AND DESIGN A COMPUTER PROGRAM OR ITS WORK

Lutfi Yousif

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 17-33

Electronic system of injecting the fuel which entered on engines of vehicles are varied and plenty, a study was occurring for system of injecting the fuel of type (multi port)in which a group of allergies sensors is used , then a study of changeable work of these allergies sensors under temperatures and from resistance , voltage ,and the magnetic field , and number of cycles for the engine , amount of speed of vehicle , and marks of presenting of spark . The results:
1. A high resistance from the allergies sensors (cold engine) equal to high voltage equal to plenty of fuel ,A low resistance from the allergies sensors( Hot engine )equal to low voltage equal to few of fuel.
2. A small opening for disk of something equal to voltage of allergies sensors is low equal to few of fuel. A large opening for disk of something equal to voltage of allergies sensors is high equal to plenty of fuel.
3. A high system in the pressure equal to low voltage equal to a more timing equal to iess fuel
A low in the pressure equal to high voltage equal to less timing equal to more fuel
4. A cold temperature of an air equal to high resistance equal to high voltage in the computer equal to more fuel .A warm computer of an air equal to resistance equal to low voltage in the computer equal to less fuel.
5. A low speed of vehicle equal to A weak magnetic field equal to A low voltage of computer. A high speed of vehicle equal to a high magnetic field equal to a high voltage of a computer.
6. Field of the normal work for allergy of the roads between 1,5-3,5 volt less or more from that is leading to delaying of timing at + marks , and depending on these changeable by visual basic language a design of computer program for a weak of allergies sensors in engine of vehicle is occurred.

NUMERICAL SIMULATION OF THE LAMINAR FLOW OF NON-NEWTONIAN FLUID THROUGH A DISK-TYPE PROSTHETIC HEART VALVE

F. Kh; Tazyukov

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 26-39

ABSTRACT:-This work presents the numerical simulation of the laminar flow of Non-Newtonian fluid in a planar channel, which includes locking structure, consisting of the support ring and movable valve. Investigated characteristic of fluid flow in valve, fitted with an artificial valve, as well as the flow various emulsions in channels containing locking valves. As the rheological constitutive relation, the model of a Generalized Newtonian Fluid, predicts the effect of anomaly viscosity. The governed equations that describe the flow were integrated by the Finite Volumes Method, using SIMPLE algorithm. The mesh is structured, with rectangular volumes. Several boundary conditions were explored, being the more realistic results obtained by prescribing the inlet velocity field and atmospheric pressure at the exit. Stream function, mean axial velocity profile, normal and wall shear stresses distributions in the flow field surrounding the prosthetic valve are computed for various values of Reynolds numbers (Re=30, 60 and 90).
Keywords: laminar flow, Non-Newtonian Fluid, artificial valve, planar channel, Finite Volume Method, SIMPLE algorithm.

EFFECT OF SURFACE ROUGHNESS ON BONDING FORCE OF OFHC COPPER USING EPOXY

Saleh Karem Wheed

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 34-42

ABSTRACT:- The effect of five different surfaces roughness of Oxygen Free High Conductivity Copper (OFHC) on shear strength of bonding OFHC with Pearlitic Gray Cast Iron (PCI) and Graphite using Epoxy was study. The results demonstrate that the increase of surface roughness increasing shear strength when bonding similar OFHC, but the lowest surface roughness of PCI specimens gave the highest shear strength (5.8MPa with emery paper of grain size ASTM grit 1200). In another hand the results show that the highest shear strength (11MPa) can be obtained with emery paper ASTM grit 800 when bonding similar specimens of graphite. The highest shear strength of dissimilar metal can obtain (7.8MPa) when bonding OFHC to PCI, but the bonding of Copper to graphite gets only 6.9MPa.

STUDY AND DESIGN THE HYDRODYNAMIC DEEP DRAWING PROCESS FOR BLANKS OF NON UNIFORM THICKNESS

Saad Theeyab Faris

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 40-56

ABSTRACT:- In this study a numerical procedure was proposed for the design of deep drawing process using finite element method (F.E.M) through program code (ANSYS 11) simplified 2-D ax symmetric model of conical cup are been developed. The process of hydrodynamic deep-drawing (HDD) has been modified to draw tapered blanks of small angles , this option unattainable in classical deep-drawing processes has its applications in producing specially –dedicated products .But more generally this process is aimed at decreasing the demand for a strict uniformity of blank thickness and thus relaxing the costly tight tolerances on the preformed blanks. The idea rests on changing the customary clamped die to a self aligned die by letting it be semi- spherical with rotational degrees of freedom.
The automatic self alignment of the die to the current angle of the blank arises from the very nature of the hydrodynamic fluid pressure beneath the blank.
The solution for the statically admissible stresses throughout the flange is produced in an asymptotic expansion fashion. With the inclusion of thickness variation interfacial friction and exponential hardening of the material. Expressions for the limit drawing ratio ( LDR )as a function of the angle of the tapered blank (beside other relevant parameters ) are developed . They are compared favorably with experiments produced on a specially built apparatus.

STUDY THE EFFECT OF PRODUCED TEMPERATURE DUE TO FRICTION ON THE BEHAVIOUR AND CHARACHERISTICS OF THE DRY SLIDING WEAR OF THE ACICULAR BAINITIC DUCTILE IRON

Dhia Ahmed Salal

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 43-54

ABSTRACT:- This research paper shows the effect of the rising temperature due to the friction between the mechanical parts which has an effect on the behaviour and characteristic of the dry sliding wear. Specimens of ductile iron are used in this research for this purpose under the effect of certain applied loads and sliding speeds. It has shown that, the mean temperature is increased with the sliding speed . This research has proved that , the average of the wear can have a high values under the temperature range (300-400)C and its maximum value can be obtained at the sliding speed (1.406) m/sec. The applied load on the ductile iron specimen can be seen in a linear relationship with the average of the wear in all sliding speeds while, at load of (40)N a maximum average wear can be obtained . This research also shows that, the friction factor is increased with the increasing of the surface temperature due the hardening of the graphite layer with the temperature rising.

DIE FAILURE UNDER EFFECT OF DIFFERENT STRESS CONCENTRATORS WITH STATIC AND DYNAMIC LOADING

Mustafa Ahmed Rijab

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 55-65

ABSTRACT:- Forming dies contain one form or another of stress concentrators due to shape corners, holes and notches that contribute to die failure. Avoiding and minimizing the effects of such concentrators is vital in die design and fabrication. The purpose of this paper is to study the effect of multiple concentrators along one axis in an infinite plate subject to tension loading. The study was carried out using Finite Element Method. The present results indicated that stress concentration in the notch has occurred at or near the normal to loading direction. Results concerning multiple stresses concentration factors increases or decreases depending on: the Notch angle, Notch depth, and Notch root radius.

EFFECT OF OXYGEN ON SI ETCH PROFILE USING DC SF6 PLASMA MICROMACHINING

Shrok Abdullah

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 57-66

ABSTRACT:- Plasma etching with tapered profile structure (high aspect ratio structures) in silicon is an important step in manufacturing capacitors for memory devices and integrated components of microelectromechanical systems. In these applications, the goal is to etch an isotropic deep features with high etch rates and with tapered profile while maintaining good uniformity. This study presents a utilization of SF6/O2 glow discharge plasma in silicon etching. The effects of etching gas (SF6) pressure and addition of oxidation gas ratio on the etching rates have been investigated. In plasma etching; the balance between feature sidewall passivation and feature bottom etching lead to anisotropic etching. Since plasma etching process depends on the chemical reaction, its rate is dependant on the diffusion rate of the reactive species generated by the plasma to the etch front and the etch products away from the etch front which affected by the sidewall passivation. Results show that in such plasma process, both etching and passivation reactions occur at the same time. These etching and passivation reactions lead to taper etch profiles when O2 ratio was 10%. Visualization of profiles for N-type and poly-type Si wafers using optical microscopy is complimented by plasma etching rate. Key words: SF6plasma, micro etching, taper profile.

STUDY OF ELECTRICAL PROPERTIES OF HIGH FUSING PORCELAIN PREPARED FROM IRAQI RAW MATERIALS

Mohammed Kasim Salman

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 66-78

ABSTRACT:- In this research study some electrical properties of porcelain bodies prepared from Iraqi raw materials, where the observed changes in these properties change the conditions of the formation of the porcelain body and conditions of measuring these properties, the same conditions that are likely to have been the separation during the currency of an electrical insulator. And found that the dielectric constant decreases the increased frequency of measurement and drop the smaller-sized granular material to potash feldspare. Also found that the loss factor of the body increases with increasing porosity of porcelain body, and dielectric strength of porcelain insulator less with increasing temperature and increases with increasing the thickness of the insulator.

FINITE ELEMENT ANALYSIS OF LASER BEAM SPOT WELDING OF ALUMINUM (2014-0)

Latfe Y.Zedan

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 67-75

ABSTRACT:- In this paper, an axis-symmetric finite element (F.E.A.) model for the resistance spot welding (RSW) of Aluminum 2014-O is developed using the (F.E.A.) software ANSYS(11). It accounts for the interactions of mechanical, thermal phenomena.
The (F.E.A.) is accomplished through the laser beam contact characteristics and thermal effects of Aluminum due to being heated to a high temperature. The phase change due to melting is accounted for a very small area near the laser spot. At the same time, temperature-dependent variable material properties are used for the simulation. In addition shear stress and strain distribution were calculated with a comparison with experimental work of recent studies.

CALCULATION OF A DORSIFLEXION ANGLE OF A PROSTHETIC FOOT FOR AMPUTEES BY USING DEVELOPED TACTILE DISPLACEMENT SENSOR

Muhsin J. Jweeg

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 76-91

ABSTRACT:-This research aims to design, construct, and evaluate a tactile sensor for measuring displacements. The sensor is then employed in a developing computerized displacement measurement in order to assess its potential in sensing and evaluating a dorsiflexion angle of a new dynamic prosthetic foot for amputees. The developed system consists of three main parts namely, the sensor, the data acquisition unit that includes an analogue to digital (ADC) module, and a computer to aid in the processing of acquired data.
One type of tactile sensors was used in the investigation. That is Potentiometric-based displacement sensors. That sensor provide analogue output signals, hence, to enable its input to the employed computer these signals are converted to digital type by the developed ADC-based module which is interfaced to the computer via the Enhanced Parallel Port (EPP).
A number of tests were conducted to establish valid calibration of the system. Early experimental results showed that there are matching between the obtained results and the best fit lines when measuring linear displacement and using the traditional calibration method, therefore, the researcher decided to use that developed sensor in measuring the dorsiflexion angle of the new dynamic prosthetic foot and comparing the obtained results with the standard one.
Key words: Prosthetic foot, Dorsiflexion angle, Tactile displacement sensor.

THE EFFECT OF REINFORCEMENT ON THE ULTRASONIC PULSE VELOCITY FOR CONCRETE

Ali H. Hameed

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 79-92

ABSTRACT:- Two types of samples were studied in the laboratory of university of Diyala .The first sample was used cubes (150*150*150 mm) number (21),and the second sample was used slabs with dimension (500*500*150 mm) number (7),distributed the steel reinforcement with one direction Ø 12, Ø 16 mm ,with spacing (10,15,20 cm ). The reading of ultrasonic pulse velocity by two methods direct and non direct, with horizontal and vertical of reinforcement direction.
The results of the test for average three reading per point of the samples ,with different ages (7,14,28 day) respectively, show that, increase with dimension of steel bar ,age and decrease the spacing with reinforcement ,also the decrease the cover of concrete increase the pulse velocity. The reinforcement samples had showed the increasing in the pulse velocity non direct method by (7.9%, 7.6%, 6.4%) and (12.2%, 11.9%, 11.7%), two bar Ø 12, Ø 16 mm, with spacing (10, 15, 20 cm) receptively.

THE EFFECT OF FUEL WITH ADDITIVES ON THE VIBRATION DYNAMIC RESPONSE OF IC ENGINE

Mauwafak Ali Tawfik

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 92-115

ABSTRACT:- This study targets at finding the effects of methanol blending to gasoline on dynamic response of IC engine. The fuel blends were prepared by blending 0, 10 and 20 vol. % of methanol with a specified amount of gasoline. These fuel blends were designated as M0G100, M10G90 and M20G80, respectively. Base commercial gasoline (Octane No. is 81) was used in this study. The experiments were conducted on a single cylinder, four stroke variable compression “Varicomp” Dual Diesel /Petrol cycles with a dynamometric test unit type (GR0306/000/037A Prodit) under various engine speeds 1200 RPM up 2000 RPM for increment of 400 RPM at constant torque of (10 N.M), and compression ratio is 9 .The data acquired from these experiments present the relation between the cylinder pressure and the crank angle.
For the purpose of investigating the vibration response of IC engine under dynamically loaded and ignition condition, the experimented cylinder pressure profiles of (Prodit) single cylinder four stroke engine for different percentage of methanol blending with gasoline base fuel, was assumed to be created in each cylinder of (Zetor-M-Type) in-line four cylinder-four stroke engine. Transfer matrix method (TMM) was adopted to calculate the vibration of the crankshaft for the latter engine. It is accounted for the shear effect and gyroscopic effect for the mathematical model of the crankshaft and the effect of unbalance forces, Also it's accounted for the dynamic loads that are applied on main and big end bearings , and two coefficients of damping and stiffness represented the oil film for each bearing.
To embrace the theoretical side, a computer program (Fortran 90), which depends on the data acquired from the experimented work, is constructed to compute the vibration response along the crankshaft of engine for each fuel (M0G100, M10G90, M20G80) to compare the vibration for each case of cited mixture of fuel and to get the suitable fuel for engine.
The result of this study showed that the M10G90 yields the best fuel for engine to get better vibration then M0G100 and M20G80.
Keywords:- Internal combustion engine, crankshaft, vibration, gasoline, transfer matrix method

A STUDY ON THE EFFECT OF GAMMA – RAY ON STRUCTURAL AND OPTICAL PROPERTIES OF ZINC SULFIDE (ZnS) THIN FILMS

Kareem K. Mohammad

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 93-103

ABSTRACT:- In this search prepared Zinc Sulfide (ZnS) thin film by using the method of thermal evaporation in vacuum under pressure (10 -5 mbar) of thickness (200) nm on glass substrate at temperature of (100C).
Also the search had included studying some of the structure and optical properties of (ZnS) thin film before and after irradiation from Co- 60 by with double ray doses (10-20) Mrad on respectively. The results. (X-ray) examination showed that all the thin films amorphous structure before and after irradiation through the measurement of the absorption and transmission spectra within the range of wave length of (200-600) nm .It was found the absorption increases but the transmission decreases as a data of waving length with increasing of ray doses .
A calculation were carried out for measuring forbidden energy gap for direct allowed and forbidden, it was noticed that there were decreases in the value of forbidden energy gap as the doses increases also a calculation of the optical constant carried such as extinction coefficient refractive index, reflectance, real imaginary part of dielectric constant of thin films before and after irradiation.

EFFECT OF PUMPING TYPES ON OPTICAL PATH DIFFERENCE IN ND:YAG LASER ROD

Zahraa Mohamed Ali Kamil

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 116-126

ABSTRACT:- The finite element method has been used successfully to determine the temperature distribution throughout Nd:YAG laser rod subjected to one end power pumping cooled by water from the longitudinal side. Displacement, strain and stress are obtained numerically depending on the temperature distribution using Hook’s law. The influence of two types of pumping methods on temperature, displacement, strain and stress is obtained. The optical path difference is obtained and compared with a previously published experimental data and a good agreement has been found. Some conclusions are drawn; Gaussian beam pumping causes higher temperature distribution more than Top hat beam pumping at and near the center of the rod, which may cause higher optical path difference there. Even Top hat beam pumping causes some high tensile hoop stress, it may be a better choice while designing laser system since it results in low optical path difference.
Keywords:- Thermal lensing, Gaussian pumping method, Top hat pumping method, Optical path difference, Thermal stress, Nd:YAG laser rod.

LOW CYCLE FATIGUE BEHAVIOR OF ALUMINUM ALLOYS AA2024-T6 AND AA7020-T6

Zyad Nawaf Haji

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 127-137

ABSTRACT:- In this study low cycle fatigue tests were performed in two aluminum alloys with different chemical composition, namely AA2024-T6 and AA7020-T6 under same heat treatment, using standard round specimens. The tests undertaken in strain control with strain ratio Re = -1.The low cycle fatigue results are used for characterization of the cyclic plastic response and the fatigue life of the alloys. This study revealed that the strength and the different chemical composition have a significant effect on transition fatigue life. The degree of the compatibility and precipitation of elements zinc (Zn) and copper (Cu) on their parent metal lead to obtain higher fatigue properties value in alloy AA7020-T6 than alloy AA2024-T6. Moreover, the cyclic deformation behavior seems to be influenced by the strength and the different chemical composition
Keywords:- Low cycle fatigue, chemical composition, heat treatment.

REPARING OF TURBINE INNER CASE BY MANUAL METAL ARC WELDING

Atta Jalal Mohammed Atta

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 138-147

ABSTRACT:- The research consisted of performing the maintenance on the internal cover (shell) of the electric power generating unit turbine which was made of nodular cast iron that was achieved by replacing the damage part, with cast carbon steel, using manual metal arc welding, and AWS ENiFe-CI filler metal electrode. Pre-heating and post-heating were implemented to avoid the formation of brittle phase in the welded zone or Heat Affacted Zone (HAZ). The weldments mechanical tests showed that the welded zone mechanical properties were better than that of the original metal of the internal cover.

USING OF HYBRID FLAME RETARDANTS TO INCREASE THERMAL EROSION RESISTANCE FOR ADVANCED COMPOSITE MATERIALS

Ali Ibrahim

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 148-156

ABSTRACT:- This research aims to attainment two essential purposes : first, using of inorganic flame retardant which represent zinc borate to increase the flame retardancy for advanced composite material consist of araldite resin (CY223) reinforced by hybrid fibers from carbon and Kevlar fibers as a woven roving (º 45 - º 0), by using a surface layer from zinc borate as a coating layer of (4mm) thickness .Then, this system was exposed to a direct flame generated from gas flame (2000ºC) with different flame exposure distances (10 mm, 20mm), and study the range of resistance of retardant material layer to the flames and protected the substrate . Second, forming a hybrid flame retardant by added antimony trioxide to zinc borate with various amount(10%,20%,30%) to enhance the retardant action of this material to flame and exposure this hybrid material to same flame temperature and exposure distances and time periods (5-60 sec) and (5-95 sec). Method of measuring the surface temperature opposite to the flame was used to determined the heat transferred to composite material . The best results was obtained with large exposed distance and large percentage from protective layer which is zinc borate with (30%) antimony trioxide.
Keywords:- Hybrid Flame Retardant, Composite Material, , Inorganic Retardants .

NEURAL NETWORK ANALYSIS FOR SLIDING WEAR OF 13%CR STEEL COATINGS BY ELECTRIC ARC SPRAYING

Ali Khudhair

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 157-169

ABSTRACT:- Artificial Neural Networks (ANNs) are a new type of information processing technique based on modeling the neural systems of human brain. The potential of using neural networks in prediction of wear rate quantities of 13%Cr steel coating produced by arc spraying, has been studied in the present work. The material is subjected to dry sliding wear test using pin-on-ring apparatus at room conditions. Effects of normal load, sliding speed and time on wear rate have been investigated by using artificial neural networks. The experimental results were used to train ANN model successfully with accepted mean square error (MSE) of 0.00077504. The ANN predictions shows very good agreement with experimental values with correlation coefficient of 0.99778, thus ANN can be considered excellent tool for modeling complex processes that have many variables.
Keywords:- Artificial Neural Network; Wear; Coating

CAVITATION IN CENTRIFUGAL PUMPS

Mohammed Khudhair Abbas

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 170-180

ABSTRACT:- Design, operation and refurbishment of centrifugal pumps are strongly related to cavitation flow phenomena, which may occur in either the rotating runner-impeller or the stationary parts of the centrifugal pumps. The numerical simulation (ANSYS CFX software Release 12) can be use to detect the cavitation in centrifugal pump. The total pressure at inflow boundary is reduced in small increment to meet the beginning cavitation.
The CFD results computed by ANSYS CFX software can be shown that the formation bubble form in a lower pressure area which caused by high velocity fluid. Inception cavitation occurs on the blade surface where the leading edge meets the tip. For lower NPSH values the cavitation zones move from leading to trailing edge. The drop in the head-NPSH curve begins when the cavity length is reached the maximum chord length of the blade. The computational grid was generated by SFX-Turbogrid with H-Grid through the blade and flow passage.
Keywords:- Centrifugal pump, CFD, ANSYS CFX software Release 12, Cavitation

STUDYING THE EFFECT OF CUTTING SPEED AND FEED RATE ON TOOL LIFE IN THE TURNING PROCESSES

Naife A. Talib

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 181-194

ABSTRACT:- In this paper, a thorough investigation has been carried out to study the effect of cutting speed and feed rate on tool life at constant depth of cut equal to (1mm) with no cooling fluid. Different cutting speed and feed rate with constant depth of cut are used to optimize these variables for maximum life can be obtained experimentally. The experiments were conducted on the fermented low alloy steel and using high hardness cutting tool of Tungsten Carbide. It was found that the longest life of cutting tool is at cutting speed (66.88 m / min) and feed rate (0.72 mm / rev), where the life of cutting tool is(388.3 min). The shortest life of cutting tool occurring at cutting speed of (263.76m/min) and feed rate (0.8 mm / rev), where the value of the life is about (0.274 min). Thus, we clear note that the cutting speed and feed rate have a direct impact on the longevity of the kit.
Keywords:- Tungsten Carbide, Tool life, Tool wear, Turning processes, Cutting tool.

FUZZY MODELLING APPROACH FOR COP ASSESSMENT SYSTEM

Abbas Mahde Abd

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 195-212

ABSTRACT:- Manage the uncertainty and vagueness of the construction organizations performance (COP) is the appropriate tool to improve the quality and environmental aspects. Because of the benefits of their interaction, the two systems were integrated to formulate the basis for the Integrated Management System (IMS). Quality performance has been assessed to monitor the construction processes and activities status. The developed Evaluating System has been utilized different assessment criteria, sub-criteria, and their combinations. The concepts of fuzzy set theory have been introduced to represent the uncertainty and vagueness of each system requirements.
The study context is limited to construction projects to point out the using of these concepts for analyzing and improving the quality culture in this sector. The findings reflect the relative significance and the probability of fail for each article of the system components, the ability of integration for two or more systems; also some recommendations have been suggested for further development.
Keywords:- Environmental system, integration management, Quality system, construction management

INFLUENCE OF SOIL STRENGTH PARAMETERS ON THE LATERAL PILE RESPONSE

Jasim M. Abbas

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 213-221

ABSTRACT:- A three-dimensional finite element technique has been used to analyze the single pile lateral under pure lateral load. The main objective of this study is to assess the influence of soil strength parameters (c, ) on the lateral behavior of single pile. The lateral single pile response in this assessment considered both lateral pile displacement and lateral soil resistance. As a result, modified p-y curves for lateral single pile response has been improved when taking into account the influence of lateral load magnitudes and soil strength parameters. The finite element method includes linear elastic, Mohr-Coulomb and 16-nodes interface models to represent the pile behavior, soil performance, and interface element, respectively. It can be concluded that the lateral pile deformation and lateral soil resistance due the lateral load are always influenced by lateral load intensity as well as soil strength parameters.
Keywords:- piles, lateral response, soil strength parameter, 3D FE analysis.

MATHEMATICAL SIMULATION FOR TRANSIENT FLOW IN PIPES UNDER POTENTIAL WATER HAMMER

Qassem H. Jalut

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 222-236

ABSTRACT:- To protect the physical integrity of a pipeline system, there may be a need to install surge control devices, such as surge relief valves, surge tanks, or air-vacuum valves, at various points in the system. The main purpose of this study is to simulate the transient flow in pipes with water hammer using a mathematical modeling. By taking Omar Almokhtar Reservoir and Omar Almokhtar Grand Reservoir hydraulic system as a case study, where this system located at 35 Km south of Benghazi city. The analysis of simulation of this study is based on a characteristics method assisted by well known software called WANDA which was developed by Delft Hydraulics / Netherlands. Maximum and minimum pressures generated by the different scenarios implemented in this study confirm that the installed air vessels capacity of 1500 m3 are sufficient to control all pressure values within the bar rating of the installed pipes. It is also found that the pipe section just upstream of OMG reservoir air valve(s) with adequate capacity is (are) needed at this section of the pipeline. Air vessels with capacity 1000 m3 are not enough to damps the pressures that occur during transient duration.
Keywords:-Water Hammer, Transient Flow, Air vessels.

STRUCTURAL BEHAVIOUR OF FERROCEMENT SYSTEM FOR ROOFING

Wail N. Al-Rifaie

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 237-248

ABSTRACT:- The growing need for cheaper construction is much-discussed subject. Prefabricated ferrocement panels present a series of possibilities for the solution of construction problem. By using the unique properties of ferrocement with a relatively low amount of reinforcement, be composite floor and wall panels can assembled into an effective multi-purpose panel system. The major advantages of this system over current construction methods are mainly due to the reduction in structural dead load and the use of fewer building elements, which are much easier to handle.
In the present investigation, two ferrocement channel-like beams to form I-cross section beam and four ferrocement plates are cast and tested due to flexural loading. The structural behaviour was monitored by reading the deflection and by observing the crack patterns. The measured values of deflections and the observations made indicated that ferrocement can be used in construction of buildings.
Keywords:- construction, structural, ferrocement.

NON –LINEAR ANALYSIS OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH STEEL AND CFRP PLATES

Ali L. Abbas

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 249-256

ABSTRACT:- Non –linear analysis of reinforced concrete beams strengthened with bonding steel or carbon-fiber reinforcement plates has been investigated in this paper. The ANSYS computer program was used for this purpose. The finite element models are developed using a smeared crack approach for concrete , three dimensional solid elements(solid 65) for concrete, three dimensional solid elements(solid 45) for steel plate ,and three dimensional layered elements(solid 46) for carbon -fiber- reinforced plastic plate( CFRP). Three- dimensional finite element analysis was conducted to obtain the response of the strengthened beams with steel and CFPR plates in terms of applied load -deflection , tension force distribution in the strengthening plates along the reinforced concrete beams, and bond force distribution in the beam with CFRP plate and beam with steel plate. The present study contains six beams, three of them those which are tested by Zarnic et al (1999)which are regarded as case study one and the other three beams are the overhanging beams which are supposed in this study as case study two .One beam for each case study was kept as the control beam while the other two beams were externally strengthened with CFRP and steel plates. Results from the ANSYS finite element analysis are compared with those obtained from experimental results and other available numerical results. The comparisons show good accuracy.
Keywords:- Finite Element Modeling, Reinforced concrete beams, Steel plates, CFPR plates

RANDOMLY MINING OF RIVER DEPOSITS AT AL-MANSURIAH DISTRICT AND IT'S EFFECTS ON ENVIRONMENT AND ECONOMY

Thair Habeeb Al-Jebouri

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 257-267

ABSTRACT:- Study area is within lower Diyala, downstream of Diyala weir. The river deposits along Diyala River and extends to a distance of about 15 kilometers downstream of Diyala weir.
Diyala basin is divided into three parts as follows, upper Diyala. Above Derbendikhan, middle Diyala! From Derbendikhan to Diyala weir and lower Diyala. From Diyala weir to Baghdad. Origin of gravel deposits at study area are the mountains of catchment of Diyala River. There is no outcrop on the surface but only alluvial sediment deposits with thickness of 70 meter.
Gravel deposits include all rounded particles coarser than 2mm, and they are used for manufacture of concrete for building, highway, in the roads as sub-base and in earth dam as a filter. Impacts of dams on sediment yield are restriction supply of gravels to lower Diyala basin. There are more than (80) gravel pits installed along Diyala river on both sides.
Total dissolved solids of Diyala River at study area for a period of one year (2009-2010) have got the highest reading (768 ppm) and lowest reading (470 ppm) and annual average (580 ppm) with an increase of (106.2 ppm) for previously studied at 1991. Effect of randomly mining on environment is the reason behind the morphological changes of Diyala River and became more or less as artificial drainage. The removing gardens in flood plain and leaving water pool without levelling. The effect on economy is clear through the daily production that reaches approximately (6500) cubic meter and the local government should pay more attention to save this national property.

DECISION MAKING TO IDENTIFY SECTION DIMENSIONS THAT PRODUCE ECONOMIC DESIGN FOR REINFORCED CONCRETE BEAMS

Khattab Saleem Abdul-Razzaq

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 268-285

ABSTRACT:- In our life, it is on accepted fact that one of the most important human activities is decision making. It does not matter what field of activity one belongs to. Whether it is political, military, economic, or technological, decisions have a far-reaching influence on our lives. It also could be said that decision making plays an important role in structural design too. The very purpose of which is to find the best way so that a designer or a decision maker can derive a maximum benefit from the available resources.
In the work here, the aim is to find the dimensions of a rectangular beam which may give minimum cost. That was done by variation of rectangular beam height (h) from maximum height (hmax) –which it is here two or three times the beam width (b) – to the minimum beam height (hmin) which it is here indicated from the ACI-code 318-08 deflection minimum heights requirements tables. During this variation of (h), computer program calculates beam reinforcement and cost. Finally, the reader chooses the height (h) and width (b) that give the minimum cost. This search is restricted by ACI-code 318-08 beam design requirements.
This work consists of five parts. The first part deals with the economic design of simply supported rectangular beams with different (b/h) ratios for spans ranging from 2.5m to 12.5m.
The second part deals with the economic design of both fixed ends supported rectangular beams with different (b/h) ratios. The third part deals with the economic design of fixed-pinned ends supported rectangular beams with different (b/h) ratios. The fourth part deals with the economic design of continuous rectangular beams with different (b/h) ratios. The fifth part deals effect of changing the concrete cost Cc to reinforcement cost Cs ratio (i.e. Cs/Cc ratio) and the effect of changing the ratio (b/h) on design results.

EFFECT OF ACETIC ACID ON THE COMPRESSIBILITY OF GYPSIFEROUS SOIL

Safa Hussain Abid Awn

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 286-298

ABSTRACT:- Gypseous soils contains either Sodium or Calcium salts, which may be considered the most problematic material for foundation engineer. It is associated with settlement problem especially for heavy and hydraulic structures with the presence of water. The risk begins from the first period of wetting or soaking these soils from any source: (rainfall, rising of water table or from any reason). The water will fluctuate or infiltrate through the soil particles and dissolve gypsum particles that fill the voids in the soil. The soil particles will roll and slide and arrange at new positions, because of the disintegration of the soil skeleton and the loosening of soil with the continuous dissolution of gypsum, which translate the soil from solid to semi solid media, with time.
The dissolution of gypsum depends on many factors (gypsum content, temperature, atmospheric pressure, and other factors). Another important factor which is the acidity of the dissolves liquid must be considered. This study shades the lights on the effect of Acetic acid (CH3COOH) on the collapsibility of gypseous soil.
A laboratory model includes 350mm diameter and 400mm height thick plastic container and 18.4kN/m3 density gypsiferous soil prepared locally and compacted in three layers, with70%gypsum content. The stress fixed at 47kPa was applied over 50mm diameter circular footing. The relation between the soaking time and the deformation ratio (settlement/width of footing S/B%) was investigated, with 5 cycles of soaking by the Acetic acid.
The results of laboratory model tests show a pronounce effect of the acidity on the collapsibility of gypsiferous soil. The results of deformation ratio S/B% was (1.22, 8, 12, 15.7, 50%) at the end of (1,2,3,4,5) prewetted cycles by CH3COOH acid, respectively. So the effect of Acetic Acid percent was considerably accelerating the collapsibility of gypsiferous soil with cycling technique.
Keywords:- gypsiferous soil, compressibility.

A MODIFIED COLLAPSE TEST FOR GYPSEOUS SOILS

Safa Hussain Abid Awn

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 299-309

ABSTRACT:- Gypseous soil is one of soils which presents a risk for engineering structures, specially with high contamination of gypsum, because of the problem of collapse of soil under the footings, during soaking of these soils with water from any source. There is another problem causes by leaching process and the continuous dissolution of the residual undissolved gypsum inside the soil skeleton (A. Awn 2004), which creates cavities below hydraulic structures and irrigation channels and reduce the bearing capacity of soil below these heavy structures. It arises during the last two decades, the need for more practical and easier method to measure the collapsibility in the laboratory and field, since more than 10% of the total Iraqi area was gypseous soil and contain 15% to 70% gypsum.
During the last two decades the need was appear for constructing a new practical device to measure the collapsibility during the soaking or leaching test, which is easier than the conventional single or double odometer test (Jennings, J.E. and Knight, K. 1957), (Knight K. 1963). This modified device which is designed and constructed locally, was effective to measuring the collapsibility at field and laboratory in addition to the ability to measure the compressibility at long time leaching for these types of problematic soil.
A model test includes a cylindrical plastic container with 45cm diameter and 500cm height open from top to fix a water control system for fixing the head of water. An artificial gypseferous soil was prepared with (70%, 60%, 50%, 40% and 30% gypsum) was placed inside the container with 17.3kN/m3 density. A standards circular shaft applied 100kPa stress was applied at all stages of tests.
The results of model tests and the new device used in this study shows a simple, high activity in measuring the collapsibility, in addition to the ability to measure the compressibility of such soil at leaching process, at the same time.
Keywords:- gypseous soil, collapsibility, field test.

IMPROVEMENT OF SOFT CLAYS BY END BEARING STONE COLUMNS ENCASED WITH GEOGRIDS

Mohammed Y. Fattah

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 310-326

ABSTRACT:- In this paper, the finite element method is utilized as a tool for carrying out different analyses of stone column–soil systems under different conditions. A trial is made to improve the behaviour of stone column by encasing the stone column by geogrid as reinforcement material.
The program CRISP2D is used in the analysis of problems. The program adopts the finite element method and allows prediction to be made of soil deformations considering Mohr–Coulomb failure criterion for elastic-plastic soil behaviour.
A parametric study is carried out to investigate the behaviour of ordinary and encased floating stone columns in different conditions. Different parameters were studied to show their effect on the bearing improvement and settlement reduction of the stone column. These include the length to diameter ratio (L/d), end support of the stone column and the area replacement ratio (as).
It was found that the effect of encasement length ratio on bearing improvement and settlement reduction increases with the increase in the end bearing soil undrained shear strength.
The encasement of the stone column should be extended to the full stone column length to make the stone column take the full benefit of the end bearing soil support especially for long columns with (L/d) more than 4.
Keywords:- Stone columns, Encased, Geogrid, End bearing, Finite elements.

A NEW MAPPED INFINITE ELEMENT FOR DYNAMIC ANALYSIS OF SOIL-STRUCTURE INTERACTION PROBLEMS

Mohammed Yousif Fattah

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 327-355

ABSTRACT:- In numerical calculations, only a finite region of the foundation radian is analyzed. Unless something is done to prevent the outwardly radiating waves from reflecting from the region's boundaries, errors are introduced into the results. The present work studies such effects, using the finite element method with two types of transmitting boundaries at the edge of the computational grid. The first type is by using mapped infinite element and the second is by using viscous boundaries.
Two types of mapped infinite elements are derived. These types are the 8-noded infinite element extended from that of Zienkiewicz mapped infinite element and the 5-noded coding of mapped infinite element extended from that presented by Selvadurai and Karpurapu in 1988.
The mapping functions and their derivatives of the infinite elements are presented for two cases; the first when the infinite element extending to infinity in the negative ξ direction and in the second case, the infinite element is extending to infinity in the negative η direction.
A dynamic finite-element analysis is carried out for soil-structure interaction problems considering transmitting boundaries. Two types of boundaries are considered: viscous boundaries and mapped infinite elements. The results are compared for three cases; the first one using finite elements only, the second using 5-node and 8-node mapped infinite elements which were added to the finite element code MIXDYN and the third one using viscous boundaries.
In order to check the validity and accuracy of the derived infinite elements in analyzing soil-structure interaction problems considering infinite boundaries, two verification examples are considered for this purpose. The results of the modified program are compared with the results of other program software called ANSYS representing other types of elements modeling infinite boundaries using viscous boundary method.
It was found that the viscous boundaries are more effective in absorbing the waves resulting from dynamic loads than mapped infinite elements. This is clear when comparing the results of both types with those of transient infinite elements.

SOLUBILITY PREDICTION OF CO2 IN SEVERAL PHYSICAL LIQUID SOLVENTS USING CHEMCAD AND HYSYS SIMULATORS

AbdulMonem A. Karim

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 356-373

ABSTRACT:- CHEMCAD and HYSYS process simulators were used to analysis the literature experimental data and predict the solubility of CO2 in three physical solvents (sulfolane, propylene carbonate (PC), and n-methyl-2-pyrrolidone (NMP)) at different temperatures (298.15 , 313.15 , 323.15, and 373.15 K). Two thermodynamic models were used, the first using Peng-Robinson equation of state (PR-EOS) and the second using Soave-Redlich-Kwong equation of state (SRK-EOS). The solubility data of CO2 in all three physical solvents systems were correlated with CHEMCAD simulator using the SRK model without modification (kij = 0).The results showed a small deviation (less than 5%), but higher deviation (about 10%) was noticed only for CO2-NMP system at temperature 373 K. Whereas the results of PR model showed a high deviation (about 20%) with all the three physical solvents systems. Modifications performed by editing user defined binary interaction parameters (BIP) of the systems used, give good results for both simulators.
Keywords:- Solubility prediction of CO2, Physical solvents, CHEMCAD and HYSYS Process Simulators, PR-EOS, SRK-EOS.

TREATMENT AND RE-USING OF BOILER BLOWDOWN IN THERMAL ELECTRIC POWER PLANTS

Thamer J. Mohammed

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 374-390

ABSTRACT:- This work studied the utilization of a pilot plant of ion exchange as a treatment method and re-use for blowdown water in South-Baghdad electric power plant. The pilot plant consisted of two columns of QVF (4.75 cm internal diameter & 90 cm long); cation and anion exchangers’ together form the demineralization process. The study is divided into two parts; the first part is to study the effect of flow rate, bed depth, silica concentration on breakthrough time and adsorption capacity for ion exchange pilot plant. The second part is to study the effect of pH with the range of 4.5 to 10 on breakthrough time and adsorption capacity by using two kinds of cation (strong and weak cation resins
The experimental data collected were represented by two dimensional figures and fitted to a second order polynomial mathematical model, with correlation coefficient about 0.98.
The best operating condition attaining maximum breakthrough time and higher adsorption capacity at flow rate (12.46 L/hr) and maximum bed depth (50 cm) with minimum silica concentration (o.1ppm) .The system of WAC resin and SBA resin was more effective than a system of SAC&SBA resin in treating boiler blowdown water.
The cost estimation is saving 274560 $ by treating boiler blowdown water due to elimination of some processes such as coagulation, filtration and R.O processes, and also reduction in chemicals consumption.
Keywords:- Re-using wastewater, Boiler blowdown .

THE INHIBITIVE ACTION OF MAGNESIUM HYDROXIDE ON HOT ASH CORROSION OF STAINLESS STEEL IN A KEROSENE FIRED FURNACE

M. M. Barbooti

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 391-405

ABSTRACT:- The inhibitive effect of magnesium oxide on the hot ash corrosion of steel structures of power generation station was studied using a kerosene fired furnace. Three alloys were selected including [SA 178A, 209 T1, 213 T11], prepared as rectangular pieces from water wall tubes and superheater tubes of a local power station. The heating chamber of the furnace had shelves on which specimens are placed. Mg(OH)2 was mixed with synthetic slag (67%wt V2O5 and 33% wt Na2SO4) at molar ratios of 1:1, 1:2 and 1:3, respectively and applied on the surface of the cleaned specimens. The tests were carried out at fixed (4 h) and various time intervals (2-10 h) to study the normal oxidation at various temperatures (550-950˚C). The rate of oxidation is accelerated in the presence of vanadic slag and resulted in increased corrosion rate with increasing temperature (550-950 oC ). X-ray diffraction indicated the formation of NaV3O8, Na2O.V2O4.5V2O5, Na4V2O7, VOSO4, Na2SO4 and iron oxide (Fe2O3) . The weight loss of the three alloys specimens indicated a Clear reduction in the degree of corrosion with increasing Mg(OH)2 content. The scale changed into a powder form which can be easily removed from the surface of the specimens. The best results were obtained with the mole ratio 3:1, which gave inhibition efficiency of 85% at 550°C. The inhibition efficiency increases with temperature decrease. With the introduction of Mg(OH)2 with the ash magnesium vanadate Mg3V2O8 was a major constituent together with some MgO.
Keywords:- Magnesium Hydroxide, Hot Ash corrosion, Inhibition.

APPLICATION OF TWO THEORETICAL MODELS TO CORROSION OF MILD STEEL AND COPPER – NICKEL ALLOY IN HYDROCHLORIC ACID

Anees A. Khadom

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 406-413

ABSTRACT:- The aim of present work is to apply Barnartt`s three point method (TPM) and McLaughlin method on the corrosion rate data of mild steel and Cu-Ni alloy in hydrochloric acid. The data of our previous work of corrosion of mild steel and copper – nickel alloy in hydrochloric acid were taken in order to apply these methods. The parameters of these methods, such as, corrosion currents and Tafel slopes were estimated using Levenberg-Marquardt estimation method. Both methods can be used to represent the corrosion rate data with high correlation coefficient. The results were more accurate with McLaughlin equation.
Keywords:- Corrosion, three point method, hydrochloric acid, metal alloys.

EFFECT OF ORGANIC COATING ON MILD STEEL CORROSION OF REINFORCED CONCERT IN SOME GYPSEOUS IRAQI SOILS

Saad Ahmed. Jafar

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 414-426

ABSTRACT:- The present work studies the effect of different types of gypseous Iraqi soils on the corrosion rate of embedded steel in mortar, and studies the effect of coated steel and concrete on the corrosion rate. Three different types of soils were used, which were collected from different locations in Iraq, (Falluja, Kirkuk and Najif) and hydrated gypsum was also used.
Three types of organic coatings were used. Red and black oxides were used for coating the steel and asphalted bitumen for coating the mortar (concrete).
This study shows that the corrosion potential is shifted to more positive direction (more noble) for the coated steel and mortar than the un-coated steel and mortar, whereas the corrosion current for the coated steel and mortar is lower than the un- coated steel and mortar.
Kirkuk soil solution is lower corrosive than the Falluja soil solution, the later is lower corrosive than Najaf soil solution and the gypsum is the most corrosive. The expected time to visible deterioration of uncoated structures is more than ten years with Falluja and Kirkuk soils, whereas it is between 3-10 years with Gypsum and Najaf soils.
Keywords:- gypseous Iraqi soils, embedded steel, mortar, organic coating.

HYDRODYNAMICS OF A CONCENTRIC TUBES AIRLIFT REACTOR

Aseel Abd Aljabbar

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 427-444

ABSTRACT:- In airlift reactors transport phenomena are achieved by pneumatic agitation and circulation occurs in a defined cyclic pattern through a loop. In the present work, the effect of geometrical relations on gas holdup and liquid velocity, and consequently on the gas-liquid mass transfer coefficient, was studied in a 15-liter airlift bioreactor with Ad/Ar = 0.224, Ad : downcomer cross-sectional area, and Ar : riser cross-sectional area. Measurements of the volumetric oxygen transfer coefficient (KLa) were taken in a raw water-air system using a sulfite oxidation method for depleting the oxygen to zero. The unsteady state concentration of oxygen is then measured using DO probe. Different conditions were examined by varying parameters such as superficial air velocity in the riser (Usg), using two types of air sparger which have a remarkable effect on KLa values. The effect is due to their influence on gas holdup and liquid velocity, consequently affecting KLa. Superficial air velocity in the riser (Usg) ranged from 0.03 to 0.06 m.s-1 and KLa varied between 0.01 to 0.07 s-1. Empirical equations were obtained between KLa and Usg as:
KLa = 0.28 Usg 0.53 for cross sparger
KLa = 0.58 Usg 0.86 for o-ring sparger
Keywords:- Airlift, Bioreactor, hydrodynamics, oxygen mass transfer rate.

DESIGN AND SIMULATION OF ASK 31 CHANNEL FREQUENCY HOPPING SPREAD SPECTRUM (FH/SS) TRANSCIEVER SYSTEM USING CONTIGUOUS BAND PASS FILTER BANKS

Khalid Awaad Humood

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 445-462

ABSTRACT:- This paper propose a design and simulation of Amplitude Shift Keying (ASK ) 31 channel frequency hopping spread spectrum (FH/SS) transceiver system. The proposed design is implemented using Matlab/Simulink package. There are many available synchronization techniques that can be used in frequency hopping spread spectrum (FH/SS) transceiver system most of these techniques require complex search operation and hence need complex hardware. In this paper a contiguous parallel digital band pass filter (BPF) banks for 31 channel FH/SS transceiver system has been designed and implemented successfully in real time using Matlab /Simulink. This designed bank of digital filters is used as a new, simple and efficient approach for synchronization of the system. This proposed system can be used to transmit and receive digital information with a data rate of 160 k bit /sec for frequency hopping rate of 160 k hop/sec and spread the transmitted data in the high frequency (HF) band, 18.6 MHz (3-21.6 MHz). Two models of jamming: multi-tone jamming (MTJ) and hopper jamming (HJ) were designed and simulated with and without the presence of Additive White Gaussian Noise (AWGN) to test the proposed design system . The obtained results proved that the proposed system passed these tests successfully.
Keywords:- FH/SS, ASK, Contiguous BPF, Noise and Jamming.

USING NETWORK RECONFIGURATION AS A TOOL FOR MITIGATING VOLTAGE SAGS IN PRACTICAL DISTRIBUTION SYSTEMS

Balasim Mohammed

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 463-472

ABSTRACT:- Voltage magnitude is one of the major factors that influence the quality of power supply. In this paper a practical method is presented for mitigating voltage sag in power distribution systems by means of network reconfiguration. The method initially identifies the weak areas in the system when it is subjected to faults in the system. Then it tries to reconfigure the network by locating the weak areas as far away as possible from the main source. Network reconfiguration is implemented by changing the opening and closing switching status of the switches in a network. A practical test distribution system is analyzed and reconfigured to illustrate the applicability of the proposed method. The results proved that the proposed voltage sag mitigation method can improve the system voltage profile during faults and hence decrease the use of voltage sag mitigation devices. Such a technique can be used to improve power quality and reliability of power distribution networks.
Keywords:- power, distribution network, reconfiguration, voltage sag.

IMPROVEMENT OF DIRECT TORQUE CONTROL SYSTEM USING RADIAL BASIS FUNCTION NEURAL NETWORK AND FUZZY CONTROL TECHNIQUES

Mohammed Khalaf Masood

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 473-484

ABSTRACT:- Direct Torque Control (DTC) is one of the most effective and modern methods for speed control of three phase induction motors, but it suffers from some drawbacks, that it needs an estimator for the electromagnetic torque and stator flux, and the existence of inherent ripples in the output torque. So it needs to an improvement.
In this work a proposed DTC system supported by Radial Basis Function Neural Network (RBFNN) and a Fuzzy Controller (FC) are constructed to avoid the above drawbacks. The (RBFNN) is used as a rapid estimator for the electromagnetic torque and stator flux and the Fuzzy Controller is used instead of the hysteresis comparator for torque and flux errors in order to organize the switching state selector in a more accurate manner. After studying the (RBFNN) it is concluded that it will be more accurate to use it during training and simulation in the independent outputs mode for the torque, stator flux and the sector. Also, accurate results can be achieved from this network for the torque, stator flux by using different values for the spread spectrum in order to let the switching state selector acts regularly. The simulation of the proposed DTC system is done by using a (Matlab/Simulink) program. The proposed DTC system shows a considerable reduction in torque ripples, and best starting performance. This improvement leads to an ability to increase the sampling period four times the conventional one.
Keywords:- Induction Motor, Radial Basis Function Neural Network, Fuzzy Control, Direct Torque Control.

DESIGN ANALOG RC-ACTIVE 2ND-ORDER AUDIO LOW PASS FILTER (LPF)

Khalid Awaad Humood

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 485-498

ABSTRACT:- The electronic filters are considered as a very impartment element of electronic circuits . These filters have a basic rule in electronic and communication devices and systems.
Using these filters , the correct decisions can be taken depending on the applications which it have been used for it. These decision which have been done may have relations with frequency, amplitude, type of signal and the function of applications. In this research RC-active 2nd-order Low Pass Filter (LPF) is designed for low frequency (audio frequency) passing. This filter is designed and simulated using EWB technique. The simulation results obtained from implementation this designed filter is nearly identical with the results obtained from theoretical analysis approximately. These results mean that the designed filter is passed the test successfully.
Keywords:- RC, Active, LPF, Audio frequency.

EFFECT OF HEATING INTERVAL AND CONTAMINATION WITH WATER ON STEAM TURBINE LUBRICANT VISCOSITY

Shaker S. Hassan

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 3, Issue 0, Pages 499-513

ABSTRACT:- Several factors affect lubricant viscosity that make its value undesirable and out of the working range. This study includes the effect of two factors, heating interval and contamination with water, on kinematic viscosity at atmospheric pressure for steam turbine lubricating oil. The experimental program take into account increasing the temperature of the lubricant oil (ISO32) by heating to specified temperature and time interval. Also the lubricant has been contaminated with a particular water contents. The values of these factors are chosen to represent the inspected real working conditions of steam turbine lubricant at south Baghdad thermal power plant. Experimental heating intervals are (20, 40, 60, 80 and 100) hours. Heating temperature is (60)◦C. Water contamination of oil expressed as a percentage are 0.3%, 0.6%, 0.9%, 1.2% and 1.5%.
The results show that oil kinematic viscosity decreases as heating interval increased by (4.7, 12, 19.6, 27.1, 34.2)%. Also the oil kinematic viscosity decreases as contamination with water increases by (1.1, 2.3, 3.6, 4.9, 6.9) % respectively and as an average for the above heating intervals. The decrease in kinematic viscosity due to heating approximately reaches unrecommended level at 40 hours as experimental heating interval, while the decrease in kinematic viscosity of oil due to contamination with water reaches unrecommended level when water content in oil exceeds 1.5%.
Keywords: Lubricant Contamination, Viscosity, Steam turbine Lubrication.