The aim of the present work is to study the e possibility of controlling cracking due to differential temperature rise and differential shrinkage between surface and interior of mass concrete is bot climate .The experimental work consisted of meanaring temperature change with time various depths, within en the mass concrete foundation of 850 cubic meters in Measurements of the concrete shrinkage were also taken surface and st shot climate, The current understanding is that at a temperature difference of 20 C between the core of mais concrete and ita marface will cause cracking lo hot climate, higher temperature difference usually develops, and combined with shrinkage may cause development of wide cracks, even whes precautions are taken,
... Show MoreDe-waxing of lubricating oil distillate (400-500 ºC) by using urea was investigated in the
present study. Lubricating oil distillate produced by vacuum distillation and refined by furfural
extraction was taken from Al-Daura refinery. This oil distillate has a pour point of 34 ºC. Two solvents were used to dilute the oil distillate, these are methyl isobutyl ketone and methylene chloride. The operating conditions of the urea adduct formation with n-paraffins in the presence of methyl isobutyl ketone were studied in details, these are solvent to oil volume ratio within the range of 0 to 2, mixer speed 0 to 2000 rpm, urea to wax weight ratio 0 to 6.3, time of adduction 0 to 71 min and temperature 30-70 ºC). Pour point of de-w
Numerical solutions are presented for the transient natural convection heat transfer problem in horizontal isothermal cylindrical annuli, enclosed in heated inner and cooled outer cylinders. Solutions for laminar case were obtained within Grashof number based on the inner diameter which varied from 1x102 to 1x105 in air. Both vorticity and energy equations were solved using alternating direction implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. The structure of fluid flow such as a velocity vector and temperature distribution as well as Nusselt number were obtained and the effect of diameter ratio on them is examined. In addition, the Grashof number was changed with the influence of variation
... Show MoreThe volumetric mass transfer coefficient kL.a was calculated using two gases (air and CO2) in water and NaOH solution. The experiments were carried out using 0.1 m column diameter. Empirical and Artificial Neural Network (ANN) correlation were developed to predicted mass transfer coefficient in form of dimensionless groups (Sh, Re,Bo and We). The use of Back Propagation Neural Network (BPNN) gave better results than other correlations found in literature and than the empirical one found in this study.
Gypseous soils are distributed in many regions in Iraq. Therefore, it is necessary to study the geotechnical properties of such soils due to the possible large damage that may incur structures founded and constructed in or on them. The soil used in this study is from Al-Najef City, Iraq. It is poorly graded sand. It also has a gypsum content of about 28-32٪. The mineralogical and chemical properties of the soil are established at first. However, this study is concerned with the dissolution of gypsum and its effect on the soil. The importance of the progress of dissolution is verified through the study of the characteristics of the soil skeleton and the pore fluid. Three differential equations are used to study this effect, namely, conti
... Show MoreThe Digital Elevation Model (DEM) considered a common tool in producing topographic maps, orthophotos and civil engineering projects besides other different engineering applications. As a result many software packages were developed and used to produce DEM from different sources like field surveys, scanned topographic maps and stereo photos exposed from air or space.
This paper is devoted to evaluate the most suitable and accurate interpolation method in producing digital elevation model for the data gathered from existed topographic maps which are also compared with data gathered from field survey. Map scale (1:25000) with contour interval (50m) were chosen in the tests. The accuracy tests based on the National Mapping Accuracy Stand
A numerical method has been introduced to predict the flow through a complex geometry bounded by the fuselage, airfoil supports and rotating dish of the AWACS. The finite volume computational approach is used to carry out all computations with staggered grid arrangement. The (k-ε) turbulence model is utilized to describe the turbulent flow. The solution algorithm is based on the technique of automatic numerical grid generation of curvilinear coordinate system having coordinate lines coincident with the boundary counters regardless of its shape. A general coordinate transformation is used to represent complex geometries accurately and the grid is generated using a system of elliptic partial differential equations technique. The ext
يهدف البحث إلى تأكيد أهمية إتباع الإدارة السليمة والتخطيط المحكم للكلفة منذ بداية إقرار المشروع الإنشائي لتسهيل مهمة وضع الاسس الصحيحة لمتابعة وضبط كلفة المشروع بالإضافة إلى تحديد المعوقات الأساسية التي تؤثر على عملية ادارة وتخطيط الكلفة الإنشائية ومحاولة تقديم مقترحات حلول لها من خلال توضيح دور الأطراف المشاركة في العملية الإنشائية . واستنادا إلى المعلومات الأولية والقراءات الاستطلاعية والبيانات التي
... Show MoreThe static characteristics of porous floating ring journal bearing under hydrodynamic
lubrication condition when operating with an improved boundary conditions are theoretically
analyzed. An isothermal finite bearing theory was adopted during this analysis. The effect of
different parameters, namely, permeability, geometrical dimensions of the ring and the bearing are
considered. It was assumed that oil is supplied through the outside diameter of the bearing under
low supply pressure. The angular extent of the oil – film formed in journal – ring and ring – bearing
oil films was obtained by applying the integral momentum equation at the leading edge of the oil –
film to define the beginning of the oil e
In this study, a different design of passive air Solar Chimney(SC)was tested by installing it in the south wall of insulated test room in Baghdad city. The SC was designed from vertical and inclined parts connected serially together, the vertical SC (first part) has a single pass and Thermal Energy Storage Box Collector (TESB (refined paraffin wax as Phase Change Material(PCM)-Copper Foam Matrix(CFM))), while the inclined SC was designed in single pass, double passes and double pass with TESB (semi refined paraffin wax with copper foam matrix) with selective working angle ((30o, 45o and 60o). A computational model was employed and solved by Finite Volume Method (FVM) to simulate the air i
... Show MoreThe present paper describes and analyses three proposed cogeneration plants include back pressure steam-turbine system, gas turbine system, diesel-engine system, and the present Dura refinery plant. Selected actual operating data are employed for analysis. The same amount of electrical and thermal product outputs is considered for all systems to facilitate comparisons. The theoretical analysis was done according to 1st and 2nd law of thermodynamic. The results demonstrate that exergy analysis is a useful tool in performance analysis of cogeneration systems and permits meaningful comparisons of different cogeneration systems based on their merits, also the result showed that the back pressure steam-turbine is more efficient than other pro
... Show MoreExperiments were carried out to study the local and average heat transfer by natural convection in
a vertical concentric cylindrical annulus. The experimental setup consists of an annulus has a radius ratio
of 0.555 and inner cylinder with a heated length 1.2m subjected to the constant heat flux while the outer
cylinder is subjected to the ambient temperature. The investigation covers heat flux range from 58.2
W/m2
to 274.31 W/m2
. Results show an increase in the natural convection as heat flux increases leads to
an improve in the heat transfer process. An empirical equation of average Nusselt number as a function of
Raylieh number was deduced .
This paper reports the conversion of a large unsignalised roundabout (HURIYA SQUARI!) relatively close to the University of Baghdad campus to a signalized intersection. The study focused on reduction of vehicle delay and queue length at this intersection area. During the course of this research project, two software packages for the analysis and design of isolated intersection, SIDRA (Akcelik, R.1986 and 1991) and HCS (Transportation Research Board, National Research Council 1994) were available. A trial site selected and the observed dara used in the evaluation of the SIDRA and HCS outputs. The evaluation process indicated that SIDRA produce vehicle delay, which is reasonably consistent with the observed vehicle dela
Knapsack problems are a class of common but difficult (NP-complete or NP -hard) problems. Since, it is believed that no knapsack problem algorithm can be constructed whose computation time optimality increases as any polynomial function of the problem size. There is a variety of knapsack-type problems in which a set of entities, together with their values (profits) and sizes, is given, and it is desired to select one or more disjoint subsets so that the total of the sizes in each subset does not exceed given bounds and the total of the selected values is maximized. Diploid representation and dominance operator are advanced operators that attempt to improve upon the power of traditional genetic algorithms. Pseudo Meiosis Genetic Algorithm
... Show MoreThere is a problem, in Iraq, due to the multitude of malfunction after the overall annual maintenance has been achieved, and that raises the cost of continuous repairs, one of the reasons of this problem, is the absence of planned testing and automation for testing devices, the second reason is the neglect of concentrating on a database, the third one is not following an integrated testing system
for all parts, as well as, there are no documented reports for inspected parts. Most of various nondestructive inspection techniques have been achieved random selection steps. The lack of a documentation system leads to lack of historical information a bout failures parts of a boiler that affect inspection decision process. This paper summ
The aim of the present work is the adsorption of the furfural onto activated carbon where Langmuir and Freundlich equation were used to determine the adsorption isotherm in the batch experiment Continuous adsorption experiments of fixed-bed were carried out to study the effects of flow rate. bed depth, initial furfural concentration, carbon particle size to determine breakpoint time and adsorption capacity
Alginate from Large brown seaweeds act as natural polymer has been investigated as polymer and has been added to concrete in different percentages ( 0% , 0.5% , 1% and 1.5% ) by the cement weight and the study show the effect of using alginate biopolymer admixtures on some of the fresh properties of the concrete (slump & the density fresh) also in the hardened state ( Compressive strength , Splitting tensile strength and Flexural strength ) at 28 days. The mix proportion was (1:2.26:2.26) (cement: sand: gravel) respectively and at constant w/c equal to 0.47. The results indicate that the use of alginate as a percent of the cement weight possess a positive effect on fresh properties of co
... Show MoreThe Diyala River is considered the third most important river in Iraq. However, in the recent period, Diyala Governorate has been subject to several floods. This study aims to simulate an efficient labyrinth weir at the flood escape entrance branching from the Diyala River to reach the best entrance through which the flood waves can pass safely. The discharge coefficient was calculated laboratory for five types of trapezoidal side labyrinth weirs with different sidewall angles. Results showed that the coefficient discharge for the trapezoidal labyrinth side weir with an angle of the sidewall is 75ᵒ and has a discharge coefficient greater than the rest of the labyrinth side weirs. The second part of this study is valida
... Show MoreEach organization struggles to exploit each possible opportunity for gaining success and continuing with its work carrier. In this field, organization success can be concluded by fulfilling end user requirements combined with optimizing available resources usage within a specified time and acceptable quality level to gain maximum profit. The project ranking process is governed by the multi-criteria environment, which is more difficult for the governmental organization because other organizations' main target is maximizing profit constrained with available resources. The governmental organization should consider human, social, economic and many more factors. This paper focused on building a multi-criteria optimizing proje
... Show MoreThe coefficient of friction was experimentally calculated for aluminum-silicon alloys by
connecting a strain gauge to the arm of pin-on-disc wear machine in order to take microstrain
readings from the strain-meter. As-cast and modified aluminum-silicon alloys were thermally
homogenized for long periods of time (1-40hr) in order to study the effect of homogenization on
friction. Scanning electron microscopy was successfully used to build up the mechanism of surface
damage during sliding. The results showed that the coefficient of friction was increased with
increasing bearing pressure for as-cast, modified and homogenized aluminum-silicon alloys.
Thermal homogenization led clearly to remarkable changes in the friction
In order to make a balance between the increasing of potable water demand and the available
quantity, a pipe network should be managed in an optimal hydraulic operation state. The optimal
operation of a water supply network leads to minimize the effect of the variance in pressure
between the available and minimum required pressure head. It simulates the hydraulic model and
puts the optimized project with the constraints (minimum design head=20 m, and the available
commercial pipe diameter, 1600³D³250 mm). The objective function is to minimize the cost for
the suggested hydraulic solution to a minimum value. Pressure uniformity coefficient (UC),
Standard deviation () and coefficient of variance (Cv) are used to sho
Resistance spot welding (RSW) aluminum alloys has a major problem of inconsistent quality from weld to weld, because of the problems of the non-uniform oxide layer. The high resistivity of the oxide causes strong heat released which influence significantly on the electrode lifetime and the weld quality. Much effort has been devoted experimentally to the study of the sheet surface characteristics for as-received sheet and surface pretreatment sheet by pickling in NaOH and glassblasted with three thicknesses (0.6, 1.0, and 1.5 mm) of AA1050. Three different welding process parameters energy setup as a low, medium, and high were carried. Tensile-shear strength tests were performed to indicate the weld quality. Moreover, microhardness tests,
... Show MoreThe present work describes the development of code for trim and longitudinal stability analysis of a helicopter in forward flight. In general, particular use of these codes can be made for parametric investigation of the effects of the external and internal systems integrated to UH-60 helicopters. A forward flight longitudinal dynamic stability code is also developed in the work to solve the longitudinal part of the whole coupled matrix of equations of motion of a helicopter in forward flight. The coupling is eliminated by linearization. The trim analysis results are used as inputs to the dynamic stability code. The forward flight stability code is applied to UH-60 helicopter.
Soil-structure frictional resistance is an important parameter in the design of many foundation systems. The soil-structure interface area is responsible for load transferring from the structure to the surrounding soil. The mobilized shaft resistance of axially loaded, long slender pile embedded in dense, dry sand is experimentally and numerically analyzed when subjected to pullout force. Experimental setup including an instrumented model pile while the finite element method is used as a numerical analysis tool. The hypoplasticity model is used to model the soil adjacent to and surrounding the pile by using ABAQUS FEA (6.17.1). The soil-structure interface behavior depends on many factors, but mainly on the interface soi
... Show MoreThe limitations of wireless sensor nodes are power, computational capabilities, and memory. This paper suggests a method to reduce the power consumption by a sensor node. This work is based on the analogy of the routing problem to distribute an electrical field in a physical media with a given density of charges. From this analogy a set of partial differential equations (Poisson's equation) is obtained. A finite difference method is utilized to solve this set numerically. Then a parallel implementation is presented. The parallel implementation is based on domain decomposition, where the original calculation domain is decomposed into several blocks, each of which given to a processing element. All nodes then execute computations in parall
... Show MoreThrough an experimental program of eighteen specimens presented in this paper, the bond strength between reinforcing bar and rubberized concrete was produced by adding waste tire rubber instead of natural aggregate. The fine and coarse aggregate was replaced in 0%, 25%, and 50% with the small pieces of a waste tire. Natural aggregate replacement ratio, rebar size, embedded rebar length, the rebar yield stress of rebar, cover, and concrete compressive strength were studied in this investigation. Ultimate bond stress, bond stress-slip response, and failure modes were presented. The experimental results reported that a reduction of 19% in bond strength was noticed in 50% replaced rubberized concrete compared with convention
... Show MoreAn optical fiber communication system for transmitting eight time division multiplexed analog signals each of bandwidth of 500 Hz was designed and implemented. The system utilizes the 8051 microcontroller as a parallel to serial converter in the transmitter side and parallel to serial converter in the receiver side in
addition to the control process of the multiplexer and demultiplexer in both sides and for serial transmission via its RS232. The transmitted signal is subcarrier intensity modulated using the Amplitude Shift Keying (ASK) modulation technique with a carrier of 20 MHz. A laser diode of the type HFCT-5205 at 1300 nm wavelength was used as an optical carrier generator with an emitted optical power of -10 dBm, and a HFCT-S20
Activated carbon has been used as an adsorbent in this work to remove mercury from aqueous solutions. The aim of the work is to test how best activated carbon can be used as an adsorbent for mercury. Equilibrium isotherms, both, Dubinin-Redushkevich, and Temkin have been test. The batch experiments were conducted at room temperature (30oC) and at the normal pH (7.0±0.1) of the solution. HYBRID fraction error function analysis shows that the best-fit for the adsorption equilibrium data is represented by (D-R) model rather than Temkin model. Its found that the correction factor (R2) for (D-R) is 0.9928 while for Temkin model is 0.942, also the HYBRID fractional error was conducted for the both models and (D-R) model give minimum value of
... Show MoreIn this paper, a shallow foundation (strip footing), 1 m in width is assumed to be constructed on fully saturated and partially saturated Iraqi soils, and analyzed by finite element method. A procedure is proposed to define the H – modulus function from the soil water characteristic curve which is measured by the filter paper method. Fitting methods are applied through the program (SoilVision). Then, the soil water characteristic curve is converted to relation correlating the void ratio and matric suction. The slope of the latter relation can be used to define the H – modulus function. The finite element programs SIGMA/W and SEEP/W are then used in the analysis. Eight nodded isoparametric quadrilateral elements are used for modeling
... Show MoreThe two dimensional steady, combined forced and natural convection in vertical channel is
investigated for laminar regime. To simulate the Trombe wall channel geometry properly, horizontal
inlet and exit segments have been added to the vertical channel. The vertical walls of the channel are
maintained at constant but different temperature while horizontal walls are insulated. A finite
difference method using up-wind differencing for the nonlinear convective terms, and central
differencing for the second order derivatives, is employed to solve the governing differential
equations for the mass, momentum, and energy balances. The solution is obtained for stream
function, vorticity and temperature as dependent variables