The transient performance (acceleration and deceleration) analysis of turbojet gas turbine engire has been carried out in the present work. Transient simulation of the engines is based on the compatibility of flow and rotational speed but not of work. Gas turbine simulation is a general- purpose simulation developed for steady state (matching) study. Matching is achieved by zeroing the difference in mass flow rate of adjacent components, and work of compressor-turbine pairi Steady state is taken as an initial condition for transient simulation of the engine. The factors indicating engine limits such as surge margin, engine maximum temperature, and combustion chamber flameout that affect transient response has been studied. The results sh
... Show MoreThis paper will be present the success of using the World Wide Web as a platform for electronic commerce and explain the necessary security mechanisms for it, Also we will propose a new approach dealing with pre and post sales support activities by using the electronic media as integral and very important parts of the business process that can be implemented to our Iraqi small and medium enterprises.
Despite the history of Baghdad city extends into a long history, most of the contemporary buildings of Baghdad have been shaped in the era of modernity. Furthermore, most of the buildings of modernity in Baghdad are types of modernity buildings in Iraq as a whole, and due to all the joints of change and development are taking place in Iraq starts from Baghdad. Accordingly, all selected buildings, which would be presented as case studies of modernity will be exclusively in Baghdad. Although the importance of this significant modernist product, which represents the identity of Baghdad, which should be preserved by the renewal and preservation policies, the problem of research was emerged as follow: new fin
... Show MoreThe thermal behavior of an octagonal shell orbiting body in space environments had been simulated theoretically in the present work, and a simplified experimental test in a thermal vacuum chamber was also made on half-scale model of the prototype to investigate the problem. A mathematical model was built and simulated numerically by using lumped system technique and finite difference control volsme approach with explicit scheme. The body in its orbit around the earth is assumed to receive solar, albedo and earth radiation heat fluxes. The orbit is circular of (500-Km) height and (40) inclination. The developed computational algorithm is capable of calculating the heat fluxes on body faces and the temperature distribution of the body at a
... Show MoreGypseous soils can be found in arid and semi arid region. In civil engineering it can be defined that a soil is a gypseous soil when it has gypsum content enough to change the properties of this soil. Collapsibility of these soils was found to be of major importance. The collapsibility of the soil can be estimated from the term "Collapse Potential (CP)" which can be obtained from two types of tests performed in the oedometer device; (1) Single Collapse Test (SCT) and (2) Double Oedometer Test (DOT). In this study, an analysis of the results obtained by 7 researchers in Iraq was performed. The data collected included basic properties for each sample in addition to the results of the two collapsibility tests. A total of 50 samples were ana
... Show MoreCO2 Gas is considered one of the unfavorable gases and it causes great air pollution. It’s possible to decrease this pollution by injecting gas in the oil reservoirs to provide a good miscibility and to increase the oil recovery factor. MMP was estimated by Peng Robinson equation of state (PR-EOS). South Rumila-63 (SULIAY) is involved for which the miscible displacement by is achievable based on the standard criteria for success EOR processes. A PVT report was available for the reservoir under study. It contains deferential liberation (DL) and constant composition expansion (CCE) tests. PVTi software is one of the (Eclipse V.2010) software’s packages, it has been used to achieve the goal.
... Show MoreWater/oil emulsion is considered as the most refractory mixture to separate because of the interference of the two immiscible liquids, water and oil. This research presents a study of dewatering of water / kerosene emulsion using hydrocyclone. The effects of factors such as: feed flow rate (3, 5, 7, 9, and 11 L/min), inlet water concentration of the emulsion (5%, 7.5%, 10%, 12.5%, and 15% by volume), and split ratio (0.1, 0.3, 0.5, 0.7, and 0.9) on the separation efficiency and pressure drop were studied. Dimensional analysis using Pi theorem was applied for the first time to model the hydrocyclone based on the experimental data. It was shown that the maximum separation efficiency; at split ratio 0.1, was 94.3% at 10% co
... Show MoreThe present work aimed to study the efficiency of nanofiltration (NF) and reverseosmosis (RO) process for water recovery from electroplating wastewater and study the factors affecting the performance of two membrane processes. Nanofiltration and reverse osmosismembranes are made from polyamide as spiral wound module. The inorganic materials ZnCl 2 CuCl2 .2H2O, NiCl.2.6H2O and CrCl3.6H2O were used as feed solutions. The operating parametersstudied were: operating time, feed concentrations for heavy metal ions, operating pressure, feed flow rate, feed temperature and feed pH. The experimental results showed, the permeateconcentration increased and water flux decreased with increase in time from 0 to 70 min. Thepermeate concentrations incre
... Show MoreA new laboratory study conducted on stepped spillways in order to investigate their efficiency of dissipating flow energy. All previous study on stepped spillway indicated that the flow energy dissipation decreased as increasing in discharge. Increasing in the step numbers and the spillway slope led to energy dissipation decrease. In this study, an experimental attempt to increase energy dissipation at variable discharges was performed on stepped spillway and that leads to decreasing the cost of initiating the stilling basin or may be ignoring it. Five spillways were constructed from concrete and tested to investigate and compare among them. Three were roughed by gravel with different size for each one, one of them was s
... Show MoreBuckling and free vibration analysis of laminated rectangular plates with uniform and non uniform distributed in-plane compressive loadings along two opposite edges is performed using the Ritz method. Classical laminated plate theory is adopted. The static component of the applied in- plane loading are assumed to vary according to uniform, parabolic or linear distributions. Initially, the plate membrane problem is solved using the Ritz method; subsequently, using Hamilton’s variational principle, linear homogeneous algebraic equations in terms of unknown are generated, the set of linear algebraic equations can be solved as an Eigen-value problem. Buckling loads for laminated plates with different combinations of bounda
... Show Moreعد تصاميم المساكن التقليدية في ريفنا العراقي مدرسة رائدة في تقديم نماذج وحلول تصميمية ناجحة ، ذلك لأنها نابعة من بيئة مجتمعنا الريفي والمتمثلة بظروفه الطبيعية وعاداته وتقاليده . تقوم فرضية البحث على اساس ان تصميم المسكن الريفي التقليدي قد تغير نتيجة لعوامل وظروف متعددة أهمها التطورات الحضرية للمدن والزاحفة باتجاه أقاليمها الريفية والتي غالباً ما تكون سريعة وعشوائية غير خاضعة للتخطيط المسبق، كما أن المسك
... Show MoreMost Internet-tomography problems such as shared congestion detection depend on network measurements. Usually, such measurements are carried out in multiple locations inside the network and relied on local clocks. These clocks usually skewed with time making these measurements unsynchronized and thereby degrading the performance of most techniques. Recently, shared congestion detection has become an important issue in many computer networked applications such as multimedia streaming and
peer-to-peer file sharing. One of the most powerful techniques that employed in literature is based on Discrete Wavelet Transform (DWT) with cross-correlation operation to determine the state of the congestion. Wavelet transform is used as a de-noisin
The effects of shot peening treatment (SPT) were studied at (10,20, and 30) minutes on the rotating bending fatigue behavior and the behavior of the alloy steel DIN 41Cr4 vibrations. The hardness test, tensile test, constant amplitude fatigue tests, and the vibration measurements were performed on samples with and without cracks at room temperature (RT), also, the fracture surface was examined and analyzed by a Scanning Electron Microscope (SEM). The results of the investigations, for example, Stress to Number of cycles to failure (S-N) curves, fatigue strength improvement factor of 5% to 10%, the decreasing percentage of maximum Fast Fourier Transform (FFT) acceleration of the shot-peened condition were compared to untr
... Show MoreSliding Mode Controller (SMC) is a simple method and powerful technique to design a robust controller for nonlinear systems. It is an effective tool with acceptable performance. The major drawback is a classical Sliding Mode controller suffers from the chattering phenomenon which causes undesirable zigzag motion along the sliding surface. To overcome the snag of this classical approach, many methods were proposed and implemented. In this work, a Fuzzy controller was added to classical Sliding Mode controller in order to reduce the impact chattering problem. The new structure is called Sliding Mode Fuzzy controller (SMFC) which will also improve the properties and performance of the classical Sliding Mode control
... Show MoreAs stuck pipe holds on to be a prime contributor to non-productive time (NPT) in drilling industry operations, efforts to restrict its incidence cannot be over-emphasized. Historically, stuck-pipe events have been shown to cost the industry several hundred million dollars annually and over 25% of non-productive time. British Petroleum Company's stuck pipe costs exceed $30 million annually. Industry-stuck pipe costs are estimated to be above $250 million annually. Major causes of this issue involve wellbore instability, differential sticking forces, improper hole cleaning, and the forming of drill-cutting beds, especially in high-angle wells. One strategy for avoiding stuck pipe issues is to predict by using the availa
... Show MoreThe use of information transfer is a major reason for the spread of information piracy, especially digital information that includes audio or other information, to preserve data. Encrypting voice messages is considered one of the most secure ways to protect information due to the difficulty of disclosing it. Our algorithm is robust, effective, efficient, and has security capabilities due to the different key lengths and block sizes (128 bits, 192 bits, or 256 bits). The Rijndael algorithm is an effective tool for encoding audio files and has won many awards. The Rijndael algorithm is compatible with many different audio formats. We will use it to encrypt WAVE files. The first step is to generate keys using the proposed m
... Show MoreThis research intents to design and laboratory implementation of a power electronic converter, which is useful for home applications, industrial, communications, street light and water pumping using solar cell source. The design is based on a step up boost DC/DC converter followed by a full wave SPWM inverter. The nominal power rating is 1.25kW and can operate from any DC source such as DC battery besides fuel cells. The system which consists of the following stages (PV, converter, inverter, DC link, filter and snubber circuit), is designed primarily with a general module depending on Orcad PSPICE program to produce power output nearly 1.25kVA at 50Hz with a pure sinewave output for both voltage and current. After designing and simulatin
... Show MoreMany useful softwares in projects management are available now. Ms Project and Primavera are some
examples of these softwares. Those programs need to be fed by information by the user. The users
usually collect this information from the project and design documents. This collection process needs
considerable time and efforts, and usually accompanied of some errors in data transfer process.
In order to reduce the required time and efforts and to eliminate individual errors in data transfer
process, an Integrated System is needed. This Integrated System can extract the graphical information
from an AutoCAD drawing and transfer it to a digital form suitable for processing in the project
management softwares such as Exce
Computations of the relative permeability curves were made through their representation by two functions for wetting and nonwetting phases. Each function contains one parameter that controls the shape of the relative permeability curves. The values of these parameters are chosen to minimize an objective function, that is represented as a weighted sum of the squared differences between experimentally measured data and the corresponding data calculated by a mathematical model simulating the experiment. These data comprise the pressure drop across core samples and the recovery response of the displacing phase. Two mathematical models are constructed in this study to simulate incompressible, one-dimensional, two-phase flow. The first model d
... Show MoreThe effect of considering the third dimension in mass concrete members on its cracking behavior is investigated in this study. The investigation includes thermal and structural analyses of mass concrete structures. From thermal analysis, the actual temperature distribution throughout the mass concrete body was obtained due to the generation of heat as a result of cement hydration in addition to the ambient circumstances. This was performed via solving the differential equations of heat conduction and convection using the finite element method. The finite element method was also implemented in the structural analysis adopting the concept of initial strain problem. Drying shrinkage volume changes were calculated using the procedure suggest
... Show MoreOil refineries are major contributors to local environmental problems .The main pollutants are oil , dissolved components , spent acids , suspended solids, sludge . Technically it is possible to remove all these pollutants by Physical , chemical and biological means .Oil is initially removed in the (API) separators , by skimming, while the heavy particles by scrapping . Further removal of discrete particles is done by gravity settlement in the primary settlement tank .The remaining suspended matter is removed by chemicals , that are added in the flocculation tank , while further flocs are removed in the air flotation tank . The biological treatment follows to remove the biological pollutants , usually followed by secondary settlement to
... Show MoreThis paper deals with calculate stresses in Knee-Ankle-Foot-Orthosis as a result of the effect vibration during gait cycle for patient wearing KAFO .Experimental part included measurement interface pressure between KAFO and leg due to action muscles and body weigh on Orthosis. also measurement acceleration result from motion of defected leg by accelerometer .Results of Experimental part used input in theoretical part so as to calculate stresses result from applying pressure and acceleration on KAFO by engineering analysis program ANSYS 14.Resultes show stresses values in upper KAFO greater than lower KAFO that is back to muscles more effective in thigh part lead to recoding pressure higher than pressure in shank part.
In a typical reservoir a sediment layer of considerable depth may be deposited on the top of exposed bedrock foundation. In this research an analytical solution was proposed to solve the case of the vertical acceleration with infinite reservoir with existence of such sediment layer. The results indicate that as the depth of sediment increases, the pressure increases also. The behavior is found to be affected by the change of the degree of saturation of the sediment layer. As this degree of sediment decreases the developed Hydrodynamic pressure increase. A comparison between the case of stiff and soft foundation indicates that the pressure values are always greater for the stiff foundation.
A Vierendeel truss is a hyper static frame composed of a series of rectangular or trapezoidal
panels with out diagonal members. The end conections of all members are rigid and designed to take moment. In this work, the use of fiber reinforced concrete in construction of Vierendeel trusses with nonlinear material behavior is researched. The addition of randomly dispersed discrete steel fibers to concrete improves many engineering properties of the material such as fracture toughness,
fatigue resistance, impact resistance and flexural strength. Several parameters that affected the behavior of the structure like fiber volume fraction, aspect ratio, and the position of the portion in structure that used fibrous concrete are studied.
The research aims to apply the novel forward osmosis (FO) process to recover pure water
from contaminated water. Phenol was used as organic substance in the feed solution, while sodium
chloride salt was used as draw solution. Membranes used in the FO process is the cellulose
triacetate (CTA) and polyamide (thin film composite (TFC)) membrane. Reverse osmosis process
was used to treatment the draw solution, the exterior from the forward osmosis process. In the FO
process the active layer of the membrane faces the feed solution and the porous support layer faces
the draw solution and this will show the effect of dilutive internal concentration polarization and
concentrative external concentration polarization.
In th
Rhythm is considered one of the creative concepts in the recent architectural thought; it has emerged clearly as a mean of creating the highest levels of creativity in architecture, especially in contemporary architectural movements. The importance of rhythm has emerged, especially, when the architecture , its beginnings concentrated on the principle of the links with poetic structures. Many architectural studies deal with concept of rhythm in architecture with different ways various according to the trend of each study, this show the importance of studying the concept of rhythm in the architectural field in general. This study try to focus on the utilization of rhythm as creative system in architecture of heritage and contemporary
... Show MoreIn this paper the finite element method has been used to determine the fundamental natural
frequencies of a pre-twisted plate mounted on the periphery of a rotating disc. Three dimensional,
finite element programs was built using three noded triangular shell element as a discretization
element for cantilever plate, this element has six degrees of freedom at each node. All formulations
and computations are coded in (FORTRAN-77). The investigation covers the effect of speed of
rotation, disc radius, aspect ratio, pre-twist angle and skew angle on the vibration characteristics of
rotating cantilever plate. For this analysis, the initial stress effect (geometric stiffness) and other
rotational effects except the corioles
Tacheometry is used to measure the lengths of traverse sides, to check the more accurate taped distances in order to uncover gross errors or mistakes and to determine differences of elevation between points. It's most general use is found in the compilation of planimetric and topographic maps by field methods alone, by which distances, elevations and directions to points are to be determined from field control points whose positions have been established by a higher order of accuracy. The principles of stadia measurement by use of the transit or theodolite or total station is one of the main method of tacheometry. This paper presents the principles of stadia measurement and a computer program MSM (Modeling the Stadia Measurements). The p
... Show MoreThis paper proposes a self organizing fuzzy controller as an enhancement level of the fuzzy controller. The adjustment mechanism provides explicit adaptation to tune and update the position of the output membership functions of the fuzzy controller. Simulation results show that this controller is capable of controlling a non-linear time varying system so that the performance of the system improves so as to reach the desired state in a less number of samples.
Reinforcement of refractory castables with steel fibers improves their strength for cracking and spalling and expands the service life.
The results show that raising the temperature from 700°C to 900°C causes an increase in porosityand decrease in bulk density for refractory castables. This happens because of decomposition of the hydraulic bond of alumina cement. When the temperature is raised higher than 900°C, ceramic bond is formed as a result of sol dreaction between alumina cement and bauxite aggregate. This leads to reduction of the porosity ar d aincrease in the bulk density. Steel fibers are affected positively in reducing the porosity ardaincreasing the bulk density for refractory castables. This positi
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