A constitutive law can be defined as a mathematical functional relation between physical quantities
such as stress and strain and may take other factors like time, temperature and additional material
properties into account. In this paper, the endochronic model is used to predict the stress-strain relations of two Iraqi clays. This model is a viscoplastic one but without introducing a yield surface. It encompasses
material behaviour such that the current stress state is a function of strain history through a time scale called “intrinsic time” which is not the absolute time but a material property. The simulation showed that the model overestimates the strains for all cases studied. This may be attributed to the material para
Water injection equipments such as pipelines, which are used in the second recovery of oil in the Al-Ahdeb wells, suffer from the corrosion in water during maintaining vacuum deoxygenated tower that used to decrease concentration of the dissolved oxygen gas in the water from 6.2-9.1 ppm to o.5 ppm. This study involved calculation the corrosion rates of the internal surfaces of the
pipelines either during operation of the vacuum unit or when the tower out of operation. Finally, find the solution by one of the following suggestions. In the first suggestion removal of the dissolved O2 from water is achieved by increasing the dosage of the oxygen scavenger (sodium sulphite). The second suggestion involves removing the dissolved O2 from w
Soil in general is not a linear material, in which the relation between stress and strain is more complicated than the simple, linearly elastic relation. To make accurate deformation analysis of clay deposits, the incremental Biot's theory of consolidation is used together with elasto-viscoplastic constitutive relations based on the critical state concept using the modified Cam-clay model. One and two dimensional consolidation problems were analyzed numerically by the infinite-finite elements. Results show that the proposed method can describe the effect of sample thickness on consolidation phenomena. Also the two dimensional behavior of a clay foundation during the construction of embankment was analyzed.
Electrocoagulation is an electrochemical method of treating polluted water. Electrocoagulation and electroflotation are two techniques involving the electrolytic addition of coagulation metal ions directly from sacrificial electrodes by introducing an electrical current into the medium for the treatment of a wide range polluted water in an even wider range of reactor design, application of an electrical field prompts electrolysis of the water medium and generates particular quantities of hydrogen gas. The process works best with water's pH in range 7.0-7.5 and will still often work less efficiently in the range 3.5 <pH<9.The effects of electrocoagulation process are in reduction water turbidity in relation to electrical current and
... Show MoreModal testing has become commonplace in many industries today as a research and development tool. In this capacity, it is used primarily during product prototype development and for vibration problem in general. Many types of structural or parts faults will cause changes in the measured dynamic response of a structure. These changes will, in turn, cause change in the structure's modal parameter. The purpose of the present work is to propose an improved damage detection and location based on the measurement of modal parameter (natural frequency and mode shape) before and after faults, which they have varying extents, for three different sizes of Aluminum casing plates. This local damage can be translated into or characterization as a redu
... Show MoreFao region is characterized by weak soft silty clay to clayey silt thick layer which extends to a depth of about 20 m. The construction of some structures on such soils may needs piles. During the installation of driven piles, the soil geotechnical properties are exposed to significant changes result due to shearing under large shear strains. These changes significantly decrease the shear strength of the virgin soil due to the destruction of soil structure caused by remolding. The degradation of shear strength is usually followed by strength regaining which is called “Thixotropy”. In this study, the thixotropic effect on Fao clay was investigated. Many disturbed and undisturbed soil samples were brought from Fao regi
... Show MoreThe present work is concerned with the theoretical and experimental investigation of flow pattern of Newtonian fluid in liquid mixing process in stirred tank with flat blade impeller. A threedimensional model for mixing process was simulated. The effected parameters are rotation speed and impeller diameter. Continuity, momentum, and turbulent equations were solved by ANSYS package software 5.4 code with FLOTRAN/CFD based on Finite Element method. In the experimental work, two visualization methods are used in this work, the first method is the acidbase reaction visualization method and the second is the particle distribution visualization method.
Different chemical materials were used in the first method, NaOH as a base, 2 4 H SO as a
This paper describes a numerical study of natural convection heat transfer and fluid flow characteristics inside a cavity with wavy vertical walls. The bottom wall is heated by spatially varying temperature and other three walls are kept at cooled temperature. Governing equation was discretized using the finite volume-method with staggered variables arrangement in curvilinear coordinates. Two geometrical configurations were used in this study for symmetrical and unsymmetrical wavy vertical walls (total of 132 cases) for range of Ra=100 to 106 and fixed Prandtl number (0.71). The effects of the wave geometry, wave amplitude, number of undulation, and Rayliegh number on flow behavior, thermal field, local Nusselt number and Nusselt number
... Show MoreThree revolutions characterize the age of information: Information Revolution,Technology Revolution and Media Revolution. These revolutions developed and interacted with each other in an amazing way. Way to an extent that it becomes a title to our
contemporary architecture. These revolutions changed people‟s thoughts, behaviors, and traditions. The effect of technology on the urban structure generally and the urban space specifically changed the physical structure of these spaces as a necessary result to the change of intellectual structure in community. The information revolution changed a lot of the common urban space„s characteristics and concepts as well as an extreme change in concepts related to the space.
The new though
The verse (35) in SURA (AL- Nur) in the HOLY QURAN has inspired the author to look into the possibility of using Olive Oil as active dye laser material. Olive Oil which is classified as organic compound, having a good properties candidate it to be used as active dye laser material. The emission spectrum diagrams at some of absorption peaks (414, 536, 632 and 670) nm will be measured. These diagrams have been used to determine the Fluorescence quantum yield, Oscillator strength, Einstein coefficients for the spontaneous emission, Radiative and Fluorescence lifetime and absorption and cross sections. It has been found that fluorescence occurs at 669 nm for the entire absorption spectrum. Fluorescence of Olive Oil has been experimented usin
... Show MoreThe hydrodynamic and thermal boundary layers have great effect on the fluid flow and heat transfer between rotating turbine blade. In the present work, the flow and heat transfer is analyzed numerically by solving two dimensional incompressible boundary layer equations. A ( k – ε ) turbulence modeling is used to obtain the eddy viscosity. The finite volume method is introduced to carryout all computational solution with staggered grid arrangement. Due to complex physical domain the original coordinate system is transferred to non orthogonal coordinate system. The calculation of present work done for rotating two dimensional turbine cascade with different rotating speeds (1500 rad/s, 1800 rad/s, 1900 rad/s), and for different Reynolds
... Show Moreجاءت فكرة البحث من اهمية موضوع استهلاك الطاقة في المدن حيث تواجه مدن العالم بشكل عام والمدن العراقية بشكل خاص تحديات بيئية كبيرة من تصاعد نسبة الانبعاثات الكربونية مما يستوجب ايجاد الحلول اللازمة من خلال فهم عملية مدخلات ومخرجات المدينة المتمثلة بعملية الايض الحضري والغازات الدفيئة وانواع مصادر الطاقة وقياس بصمة الطاقة لمنطقة الدراسة وعلاقة استعمالات الارض في استهلاك الطاقة وتوصل البحث الى عرض النتائج ا
... Show MoreThe behaviour of batter piles under inclined compressive loads is of considerable importance,yet, not enough information is available in literature on the subject. The tests canied out in this paper were performed on a single inclined pile under various load inclinations in sand. The results indicate that the highest ultimate compressive load for vertical pile occurs at (30) load inclination. At small load inclinations, a positive batter pile has greater ultimate compressive load than that of a negative batter pile. The trend changes at higher Ioad inclinations. The slip surface analysis is recognised to be too complicated to have a definite
solution.
The superhcater zone of the boiler is the convective heat transfer region of the boiler, that is the heat in this region mostly transferred by the convection between the flew gases outside and steam inside tubes. The factors that effected the heat transfer rate and heat transfer coefficient in the Mosiab power station boiler (980000kgihr capacity under pressure of 175bar) at its superlieater is studied here. The super heater is divided into two parts, primary and secondary super heater. Each part is
divided into many zones depending on the pipe size and material. The effect of boiler load mass flow rate of steam on the heat transfer rate, heat transfer coefficient, steam temperature is studied. It is concluded that as the load on the
This research deals with the stress analysis of typical underground tunnels using isoparametric finite elements. Enhanced soflware is used for predicting and analyzing this behavior by using a single phase formulation. This software was developed from an original Computer code namea MXOYN The finite element method is used to solve the dynamic equiiibrium equation with step-by-step tirre
integration schemes. A selected type of dynamic load was chosen which is blast loading. Frictional and paniculate materials, i.e., concrete and soil, are considered. The soil and concrele structures arc analyzed where a dynamic elastic model for concrete and a linear elastic one for soil are used. The soil is further analyzed by a bounding surface
This paper describes a stego system in which a gray scale image is embedded in another one.Wavelet transform of both the cover image and the embedded image is used to sort their subbands energies to guarantee that the embedded image will be inserted in the low frequency components of the cover image with little perceptual distortion. Embedding by this way increases the robustness of the system but affects the syster 1 imperceptibility, so a variable scaling factor (a) is used to attenuate the components of the embedded image before adding them to those of the cover image. It is found that the stego image with peak signal-to-noise ratio (PSNR) of about 30 dB has goo 1 imperceptibility.The attacker is proposed to be act
... Show MoreA new systematic approach is introduced and used to define and study the basic concepts of the anti-virus system. These basic concepts include definitions, design and analysis criteria, and lassifications. Also, the characteristics of the ideal anti-virus system are defined. To understand how the proposed design and analysis criteria can be used in practice, the currently available antivirus products are analyzed using the proposed criteria to see whether they meet the requirements of the ideal anti-virus system or not.
The major of DDoS attacks use TCP protocol and the TCP SYN flooding attack is the most common one among them. The SYN Cookie mechanism is used to defend against the TCP SYN flooding attack. It is an effective defense, but it has a disadvantage of high calculations and it doesn’t differentiate spoofed packets from legitimate packets. Therefore, filtering the spoofed packet can effectively enhance the SYN Cookie activity. Hop Count Filtering (HCF) is another mechanism used at the server side to filter spoofed packets. This mechanism has a drawback of being not a perfect and final solution in defending against the TCP SYN flooding attack. An enhanced mechanism of Integrating and combining the SYN Cookie with Hop Count Filtering (HCF) mech
... Show MoreThis work presents mainly the buckling load of sandwich plates with or without crack for different cases. The buckling loads are analyzed experimentally and numerically by using ANSYS 15. The experimental investigation was to fabricate the cracked sandwich plate from stainless steel and PVC to find mechanical properties of stainless steel and PVC such as young modulus. The buckling load for different aspect ratio, crack length, cracked location and plate without crack found. The experimental results were compared with that found from ANSYS program. Present of crack is decreased the buckling load and that depends on crack size, crack location and aspect ratio.
Baghdad city has been faced numerous issues related to freshwater environment deteriorations due to many reasons, mainly was the discharge of wastewater without adequate treatment. Al-Rustamiya Wastewater Treatment Plant (WWTP) have been constructed among many plants in Baghdad city to reduce the amount of wastewater discharged into natural environment and its subsequent adverse effects. This study was conducted to evaluate the performance of the plant which consist of a conventional activated sludge (CAS) and sequencing batch reactors (SBR) systems as secondary treatment units and its ability to meet Iraqi specifications. A reliability level determination and analysis also were conducted to find the plant's stability an
... Show MoreThere is no access to basic sanitation for half the world's population, leading to Socioeconomic issues, such as scarcity of drinking water and the spread of diseases. In this way, it is of vital importance to develop water management technologies relevant to the target population. In addition, in the separation form of water treatment, the compound often used as a coagulant in water treatment is aluminum sulfate, which provides good results for raw water turbidity and color removal. Studies show, however, that its deposition in the human body, even Alzheimer's disease, can cause serious harm to health and disease development. The study aims to improve the coagulation/flocculation stage related to the amount of flakes, i
... Show MoreTo damp the low-frequency oscillations which occurred due to the disturbances in the electrical power system, the generators are equipped with Power System Stabilizer (PSS) that provide supplementary feedback stabilizing signals. The low-frequency oscillations in power system are classified as local mode oscillations, intra-area mode oscillation, and interarea mode oscillations. Double input multiband Power system stabilizers (PSSs) were used to damp out low-frequency oscillations in power system. Among dual-input PSSs, PSS4B offers superior transient performance. Power system simulator for engineering (PSS/E) software was adopted to test and evaluate the dynamic performance of PSS4B model on Iraqi national grid. The res
... Show MoreThe Depleted Uranium contamination in soil was treated with chemical leaching method by using sodium bicarbonate with respect to the effect of several variables (Time, Temperature, Bicarbonate Concentration, Carbonate/Bicarbonate Ratio, Oxidative Reagent Effect, pH, Soil/Solution Ratio and Rinsing Effect after treatment) in order to decontaminate or remove Depleted Uranium to acceptable regulatory levels.
The objective is to reach a selectively extracted Depleted Uranium by using a soil washing/extraction without generating a secondary waste which would be difficult to manage and/or dispose off. Results of Depleted Uranium removal efficiency were ranged from (35.4-88.25) %.
The design and construction of an instrumented heat pipe H.P for domestic heating that uses water as a working fluid was undertaken to investigate experimentally the performance of the H.P under various operating conditions of: Power levels, water inventories and angle of inclinations. A theoretical model to predict the temperature of the condenser surface (the temperature at which heat is rejected) and system pressure at steady state conditions was developed and used to compare these parameters with the experimental findings. The model utilizes the total heat supplied to the evaporator to predict system pressure and condenser temperature. The theoretical model is suitable for vertical H.P (i.e. =0) and its predictions of condenser s
... Show MoreA numerical calculations algorithm has been developed in the present work for a thermodynamics and aerodynamic design of an axial flow compressor. The design calculations were based on thermodynamics, gas dynamic, fluid mechanics, aerodynamic and empirical
relations. A two- dimensional compressible flow is assumed with constant axial and rotor blade velocities. A free –vortex swirl distributions was used in the design. These calculations include; power of the compressor, thermodynamic properties of the working fluid, stage efficiency, number of rotor and stator blades, tip and hub diameters, blade dimensions (chord, length and space) for
both rotor and stator, velocity triangles before and after the rotor, Mach number, solidity
The research investigates the term innovation and its role in elaborating architectural practice based on diffusion. The complexity of the architectural field compared with other fields shows a problem in explaining how innovations in architecture diffuse as a thought and act in a certain context of practice. Therefore, the research aims to build an intellectual model that explains the way personal thoughts resembled by unique models introduced by creative and innovator designers diffuse in a certain pattern elaborate these models into a state of prevailing thought resembled by the movement in architecture. The research will apply its model to the more comprehensive movement in architecture, which is the modern movement,
... Show MoreFilm condensation of steam on a vertical tube is investigated numerically and experimentally,
in the present work. A mathematical model was set based on the basic conservation laws of mass
and energy, Nusselts analysis of film condensation, and empirical equations available in the
literature. Then, a simulation program in FORTRAN language was developed which simulates the
film condensation of steam on a vertical tube. A complete steam tables subprogram
... Show MoreAn experimental study is conducted to investigate the effect of heat flux distribution on the boiling safety factor of its cooling channel. The water is allowed to flow in a horizontal circular pipe whose outlet surface is subjected to different heat flux profiles. Four types of heat flux distribution profiles are used during experiments: (constant distribution profile, type a, triangle distribution profile with its maximum in channel center, type b, triangle distribution profile with its maximum in the channel inlet, type c, and triangle distribution profile with its maximum in the channel outlet, type d). The study is conducted using heat sources of (1000 and 2665W), water flow rates of (5, 7 and 9 lit/min). The water
... Show MoreThis study aims at identifying the notion of Post-Occupancy Evaluation (POE) pertinent to the performance of three general hospitals constructed inside the Sulaimani City, tracing the relationship between the quality of the indoor environments and medical staff (doctors and nurses) satisfaction level. Using some indoor environment elements in the right way will positively influence the mood, stress level of the medical staff, and patient recovery as a result. The POE toolkits (AEDET and ASPECT) have been implemented on targeted wards at the selected hospitals. AEDET and ASPECT questionnaires were distributed among 152 medical staff to obtain their perspectives. In total, 112 valid questionnaires were received. The medica
... Show MoreA theoretical study for a three-dimensional natural convection heat transfer from an isothermal horizontal , vertical and inclined heated square flat plates (with and without circular hole) has been done in the present work. The study involved the numerical solution of the transient Navier-Stokes and energy equations by using finite deference method (F.D.M.). The complete Navier-Stokes
equation are transformed and expressed in terms of vorticity-vector potential. The Energy and Vorticity equations were solved by using an Alternating Direction Implicit (ADI) method because they are transient equations of parabolic portion, and the Vector potential is solved by using an equations Successive Over-Relaxation (S.O.R) method because it i