Table of content

Journal of Engineering

مجلة الهندسة

ISSN: 17264073
Publisher: Baghdad University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

The Journal Engineering was issued in 1986. It was Stopped from 1990 – 1997 because of the economic blockade. It restarted publication after the fourth scientific engineering conference for it published the papers that were accepted in the conference.
It is a scientific engineering journal refereed by specialized and qualified professors in most of the engineering fields and those Specialists in the issued by the college of Engineering university of Baghdad .It was serenely publibued , but from 2011 it has issued of monthly for the numerous papers submitted to the journal to publish their papers in this scientific journal in addition to some of the Arabs professors because the journal is considered one of the valued journals in the Arabic homelan .
Many professions were the head editor of the journal from its first issue. The first one was prof.dr. Laith Ismail Namiq then prof.dr. Mohammed A.Alawis ,prof.dr.Ali A Al – kilidar prof.dr. Abdul-Ilah Younis and currently Prof.dr.Qais S. Ismail.

Loading...
Contact info

Jadriyah, Baghdad
Iraq
Mobile:
Email: joengbag@uobaghdad.edu.iq

Table of content: 2009 volume:15 issue:4

Article
Architectural Transformations in Holy Cities Center “ The holy city of Najaf as model ”
التحولات العمرانية في مراكز المدن المقدسة (مدينة النجف الاشرف إنموذجاً)

Loading...
Loading...
Abstract

The Architectural transformations is one of important issues that have held thought the workers in the field of architecture and design of cities, The Center of Holy Islamic Cities are affected clearly & changes caused by Increased humanitarian needs and the progress of civilization and from technology inputs. The research shows the problem very clearly in the process of development and expansion of the holy cities undergoing a difficult period for the traditional fabric as a result of the hit torn fabric and turn them into the fabric of disassembled away from the pattern of the traditional Arab-Islamic architecture, through the introduction of Extraneous elements of style and architectural details compatible with third-traditional urban fabric. The absence of a public awareness to preserve the historic buildings and the holy cities both at the individual or society or government departments are the basis of the problem, The search find a solution that comes through the face of this overwhelming power over the process of urbanization and the rapid transformation of non-accompanied versions of the forms of traditional physical and the trend towards western concepts without quotation sensitivity to the nature of cultural and architectural heritage of the holy cities and the possibility of the interdependence of these concepts with reality. Based on this study was the importance of the historical center of the city of Najaf so that we can preserve the historical identity and personality of a religious nature as a unique model for future generations holy cities of a traditional Islamic architecture. The research is divided into two main parts , the first part studied the transformations , the second part studied the transformations in the historical center of the old city of Holy Najaf.


Article
Cost Management and Planning in Construction Projects
أدارة وتخطيط الكلفة في مشاريع التشيد

Loading...
Loading...
Abstract

This research aims at emphasizing the significance of sound management and cost planning from the beginning of the project undertaking in order to facilitate the proper establishment for conducting and systemizing the project costs. Also, to determine the major obstacles that affect the management and scheduling of construction costs and to suggest solutions through demonstrating the roles of the parties involved in the project. According to the preliminary information, data, and exploratory readings collected about this matter, the research hypothesis is formulated as follows:- " In fact, there is a critical need to determine the proper fundamentals of cost conduct and planning according to a sound clear system, taking into account what is currently applied and followed in order to assess these procedures and improve them as mach as possible." In order to meet the aims of this research, a scientific methodology is pursued in :- - the presentation and review of most the local and international references that are directly relevant to the research, and aided by reports and articles from the internet from websites of engineering facilities of relevancy. - the case study for five projects. which are currently under construction in Iraq, analyzing them thoroughly in order to point out about their positive and negative aspects. - the open questionnaire and the regular closed questionnaire forms based on the data and information collected through the theoretical review and the open questionnaire to conclude and examine some concepts concerning the actual management status of cost planning. The research hypothesis has proved to be workable. Thus, it was possible to define the major obstacles that affect the process of construction cost management and planning; also, to suggest an appropriate plan for cost management and planning using a formula that facilitates the process of establishing and conducting all the details of construction cost to handle the weakness points on time, and to be able to propagate for cost management and planning and to inform the relevant parties or beneficiaries about how to take the proper decisions according to modern methods.


Article
Experimental and Analytical Analysis of Pre-Stressed Concrete Spliced Girder Models

Authors: Ali H. Nasser --- Thamir K. Mahmoud
Pages: 4087 -4106
Loading...
Loading...
Abstract

The present research is concerned with experimental and analytical studies of pre-stressed concrete spliced and non-spliced girder models. The test groups consisted of (16) girders of rectangular sections. Eight girders are spliced while the other eight are reference non - spliced girders. Each spliced girder is composed of three concrete segments connected by splices of ordinary reinforced concrete with hooked dowels different locations. The tested girders were of single span or continuous over intermediate supports. For single span girders two splices were used and post-tensioning was carried out for the full assembled girder. For the continuous girders pre-tensioned segments were connected by splices at quarter spans. Concentrated or uniformly distributed loads have been applied to the girders. The deflection was measured at mid-spans while the strain was measured at splice zones and at mid-spans. Nonlinear analysis of the girders was carried out using a modified computer program. A comparison among the experimental and the analytical results for spliced and non-spliced girders was carried out to study the effects of splicing for different girders. Results have shown that at about 50% of the ultimate load which is approximately corresponds to the serviceability limit state, the deflection of the spliced girders is greater than that of the reference non-spliced girders in the range of (10%-15%) and the ultimate loads for the non-spliced girders are greater than those of the spliced girders in the range of (12%-17%). The difference in deflection between the Finite Element and the experimental results at 50% of the ultimate load was in the range of (8%-12%). Moreover, the difference in the ultimate load between the Finite Element and the experimental results was in the range of (5%-11%).

Keywords


Article
The Effect of Operating Condition for Cumene Cracking on the Performance of Prepared HX - Zeolite Catalyst

Loading...
Loading...
Abstract

The present study reports the effect of temperature and liquid hourly space velocity (LHSV) on the cumene cracking reaction rate and selectivity by using a laboratory continuous flow unit with fixed bed reactor operating at atmospheric pressure. The prepared HX zeolite was made from Iraqi kaolin with good crystallinity .The activity and selectivity of prepared HX-zeolite was compared with standard HY zeolite and HX zeolite catalysts in the temperature range of 673-823K and LHSV of 0.7-2.5 h^-1. It was found that the cumene conversion increases with increasing temperature and decreasing LHSV at 823K and LHSV of 0.7 h^-1 the conversions 65.32, 42.88 and 59.42 mol% for HY, HX and prepared HX catalysts respectively and at LHSV of 2.5 h^-1 and the same temperature the conversions decrease to 29.24, 12.53 and 22.89 mol%, respectively .It also found that the benzene yield increases with increasing temperature at 823K and LHSV of 0.7 h^-1 the benzene yields were 58.79, 38.56 and 54.56 mol% for HY zeolite , HX zeolite and prepared HX zeolite, respectively and the selectivity to benzene is nearly constant over the studied temperatures range. The kinetics of cumene cracking ( the kinetics parameters-rate constant )and activation energy are used in this study to characterize differences between various catalysts. The reaction was found to be first order with activation energy equal to 78.58 , 89.10 and 97.77 kJ/mol for HY, prepared HX and HX , respectively.

Keywords


Article
Integration of Mobile Phones Into LAN Environment

Authors: Mohammed Dhiyaa Al-Qassar --- Hamid M. Ali
Pages: 4122 -4141
Loading...
Loading...
Abstract

The aim of this paper is to integrate mobile phones into LANs by connecting the two parties and providing the mobile with a transparent access to the services and resources hosted by the LAN. Quick assessment of the typical related approaches for accessing LAN (like WLAN and Bluetooth BNEP) shows that they are inappropriate for mobile phones. The paper further inspects the LAN access approach based on Bluetooth PAN Profile and marking up its potential drawbacks. A modified approach is proposed and implemented by altering the access nature or model from peer-to-peer communication to a client/server service providing, and switching from BNEP to RFCOMM protocol.

Keywords

Mobile Phone --- LAN Environment --- Bluetooth --- PAN --- Symbian OS --- S60


Article
Genetic Algorithm Based Load Flow Solution Problem in Electrical Power Systems

Authors: Samir Sami Mahmood --- Hassan A. Kubba
Pages: 4142-4162
Loading...
Loading...
Abstract

In this paper, a proposed method based on real-coded genetic algorithm is presented and applied to solve multiple load flow solution problem. Genetic algorithm is a kind of stochastic search algorithm based on the mechanics of natural selection and natural genetics. They combine the concepts of survival of the fittest with genetic operators such as selection, crossover and mutation abstracted from nature to form a surprisingly robust mechanism that has been successfully applied to solve a variety of search and optimization problems. Elitist method is also used in this research, and blending models are implemented for crossover operator. In the proposed work, five busbars typical test system and 362-bus Iraqi National Grid are used to demonstrate the efficiency and performance of the proposed method. The results show that, genetic algorithm is on-line load flow solution problem for small-scale power systems, but for large-scale power systems, it is recommended that the load flow solution using genetic algorithm is for planning studies. The main important feature of the purposed method is to give high accurate solution with respect to the conventional methods.


Article
Active Network Security Based RSA Algorithm

Authors: Wisam haitham abbood --- Ahmed Freidoon Fadhil
Pages: 4163-4175
Loading...
Loading...
Abstract

The difficulty of building a secure network is due to the changing nature of the enterprise coupled with the increasing sophistication of the hacker threat, both from inside and outside of the network. Active networks enable individual user or groups of users to inject customized programs into the nodes of the network. The proposed system depends on the basic concepts (authentication and authorization) and uses RSA algorithm to add additional level of security. The proposed system also depends on active packet architecture, the packet will represented in the active node as input, and when the packet is retransmitted to another active node it carries information about each node it visits. The result of execution the packet will display in the first node where the packet started.


Article
Detection of Static Air-Gap Eccentricity in Three Phase Induction Motor by Using Artificial Neural Network (ANN)

Authors: Hayder E. Alwan --- Qais S. Al-Sabbagh
Pages: 4176 -4192
Loading...
Loading...
Abstract

This paper presents the effect of the static air-gap eccentricity on the performance of a three phase induction motor .The Artificial Neural Network (ANN) approach has been used to detect this fault .This technique depends upon the amplitude of the positive and negative harmonics of the frequency. Two motors of (2.2 kW) have been used to achieve the actual fault and desirable data at no-load, half-load and full-load conditions. Motor Current Signature analysis (MCSA) based on stator current has been used to detect eccentricity fault. Feed forward neural network and error back propagation training algorithms are used to perform the motor fault detection. The inputs of artificial neural network are the amplitudes of the positive and negative harmonics and the speed, and the output is the type of fault. The training of neural network is achieved by data through the experiments test on healthy and faulty motor and the diagnostic system can discriminate between “healthy” and “faulty” machine.


Article
Studying of Heated Water Released from South-Baghdad Electric Power Station to the Tigris River

Authors: Mohammed Ali I. Al-Hashimi --- Tariq J.Al-Mosewi
Pages: 4193-4203
Loading...
Loading...
Abstract

Thermal pollution occurs when heated wastewater is discharged into rivers, lakes, oceans, or other water bodies. This will raise the temperature of the water body above its normal level and, consequently, will harm the aquatic live. Thermal Pollution problems will intensify as electricity usage increases unless substantial changes are made in the mode of discharge of the heated water. This paper is aimed to study the effects of heated water released from South-Baghdad Power Station on the water quality of Tigris River. Many parameters are test such as: Temperature (T), Total suspended solids (TSS), Total Dissolved Solids (TDS), Electrical Conductivity (EC), Hydrogen Ion (pH) and the dissolved oxygen (DO). Other parameters are tested to describe the heated water components such as Biochemical Oxygen Demand (BOD), Oil+Grease, and PO4.These parameters are compared with the allowable limits of rivers according to the Iraqi standards NO.25/1967 and found that some parameters exceed the allowable limits.

Keywords


Article
Integrated System for Air Pollution around Refineries

Authors: Muna Samir Al-Khafaji --- Rafa H. Al-Suhaili
Pages: 4204-4218
Loading...
Loading...
Abstract

A mathematical model for integrated air pollution modelling around refineries is built and named as Computerized System for Integrated Air Pollution Modelling Around Oil Refineries (CSIAPMAOR).The model based on Gaussian equation to estimate concentration of pollutants (SO2, NO2, CO, Particulates) that are emitted from a continuous air pollution elevated source. The model is designed by using Visual Basic as a main core of the system and linked with auxiliary models such as ArcMap (GIS), Surfer software, Ms-Excel and Ms-Access. The model has flexibility to select either rural, urban or stability (Smith equation) wind speed profile. It also has the option of using three types of dispersion coefficients equations for rural condition (PGT-Briggs-Martin equation) and one equation for urban condition (Briggs equation).The model has many options to display results as concentrations versus center line-downwind distance or as Three-Dimensional (3D) map. The model can compute maximum concentration with the contribution of each stack to the overall maximum concentration. Moreover the model has the ability to perform a sensitivity analysis for the effect of the most important parameters according to the Gaussian equation. AL-Doura Oil Refinery was taken as a case study using the available observed data of two sites1 and 2 for periods 15th -21st and 23rd -29th August 1997 in order to check the performance potential of the model. Results showed that Briggs equation for dispersion coefficients with rural wind speed profile has the best degree of agreement with the observed values of 0.86, 0.90 for SO2; 0.69, 0.80 for NO2; 0.73, 0.79 for CO; 0.63, 0.60 for particulates at site 1 and 2 respectively. It is found, that for AL-Doura Oil Refinery stacks number 6, 2, 7, and 3 have a large contribution on the overall maximum concentration. The model demonstrates the influence of atmospheric stability, wind speed, emission rate, exit velocity, physical height, exit temperature and rural-urban area in reducing the concentrations of pollutants. Sensitivity analysis shows that the concentrations are sensitive to stability class in comparison with other input parameters.


Article
An Experimental Study of Burr Formation in Drilling and Slot-End Milling Operations

Authors: S. A. ALRABII
Pages: 4219-4240
Loading...
Loading...
Abstract

This paper presents the results of an experimental study on the influence of the main cutting parameters on burr formation and its types in drilling and slot-end milling operations to machine low carbon and stain -less steels using HSS cutting tools and cutting fluid. Particular attention was focused on the relation between the burr type and size and cutting parameters. Therefore, a wide range of cutting speeds, feed rates, and dept of cuts were investigated to explore the optimum cutting conditions. Burr heights were measured and anal- lyzed at different machining conditions to determine the effect of the cutting speed, feed rate, and depth of cut on burr formation. The data obtained for low carbon steel were compared with those for stainless steel. Different diameters of HSS twist drills were used to observe their effects on drilling burr formation. The quantitative measurements of burrs height yield much useful information because relatively uniform small and large burrs were formed under these conditions.


Article
Investigation of Parameters Affeccting Lost Foam Casting

Authors: Ihsan K. A. Al-Naimi --- Qasim M. Doos
Pages: 4241 - 4257
Loading...
Loading...
Abstract

The lost-foam casting process using expanded polystyrene foam pattern allows more complex and detailed passages to be cast directly into the part. The advantages of the lost-foam casting process involve, forms complex internal and external shapes without cores, reduces part mass with near net-shape capability, eliminates parting lines, and reduces machining operation and costs, Complex shapes with various sizes castings were produced in this technique in the foundry of the State Company for Electrical Industrials to evaluate the process. Successful complete castings were made. Many experimental works were done to further complements about fluidity parameter dealing with lost-foam casting process. Empirical linear and non-linear formulas were obtained from those experimental works to find the minimum temperature for pouring molten metal. Aluminum alloys were the material of choice for this work, due to the best combination of mechanical properties and castability, but the performance requirements and manufacturability issues will drive the choice of a specific aluminum that was aluminum-silicon alloy, which were used in this work. The macroscopic properties of the alloy depend strongly on the microstructure. Therefore, photomicrographs of microstructures of various castings with different foam pattern densities were done and made comparisons with common sand castings. Mechanical tests were conducted on the castings which produced by the common sand casting and the lost-foam casting processes. These tests include tensile, hardness, and impact. Because of using the expandable polystyrene as a pattern that gave, more gasses in the cavity of the mold during casting, so the mechanical tests show some differences between the two processes.


Article
Evaluation of Specific Methods to Detect Crack and Damage of Mechanical Beam Structures using Free Vibration Analysis

Authors: Iqbal A. R --- Nabil H. H
Pages: 4258 -4280
Loading...
Loading...
Abstract

The importance of the beam in the service of our life and how the damaged beam costly influence the economy and even endanger the human life itself, draws our attention to study the specific methods to detect crack and damage by using free vibration analysis of mechanical beam structures. In the present research, three kinds of beam structures have been investigated namely (simply supported beam, portal frame and crane frame) by using finite element method. Six cases of damage are modeled for simply supported beam and portal frame and with seven cases for crane frame. The damage is simulated by reducing the stiffness of assumed elements with ratios (25% and 50 %) in mid- span of the simply supported beam and by introducing cracked elements at different locations with ratio of depth of crack to the height of the beam (a/h) 0.1, 0.25 for simply supported beam and 0.1 and 0.2 for portal and crane frames. A program coded in Matlab 6.5 was used to model the numerical simulation of the damage scenarios. The results showed a decreasing in the five natural frequencies with shifting in the damaged mode shape associated with their frequencies from undamaged beam which means the indication of presence of the damage. The direct comparison gives an indication of the damage but the location of the damage, is not detected. Four structural damage identification methods based on changes in the dynamics characteristics of the beam structures are examined and evaluated for damage scenarios for the three structures considered. The results of the analysis indicate that the curvature energy damage index method performs well in detecting, locating and quantifying damage in single and multiple damage scenarios for the three structures.

Keywords

Damage --- Crack --- Damage location --- Curvature --- Frame --- Frequencies


Article
Bounding Surface Coupled Finite Element Consolidation Analysis of Normally and Overconsolidated Clays

Authors: Ayad N. Al-Ebady --- Omar Al-Farouk S. Al-Damluji
Pages: 4281-4304
Loading...
Loading...
Abstract

The radial mapping version of the bounding surface plasticity model is implemented in a computer program to predict the response of cohesive soils. The eight-noded isoparametric element and Biot’s theory are used in this study for analyzing soil consolidation problems. The model has been used in the analysis for two classes of problems. The first involves the comparison of model predictions with the results of laboratory tests in compression and extension for normally and overconsolidated clays. The second class involves using the model to predict the results of one- and two-dimensional finite element problems of soil consolidation. The comparisons with experiments demonstrate that the model, through its simplicity, can describe realistically the soil response under different monotonic loading conditions at any overconsolidation ratio. The comparison between the bounding surface plasticity model with the classical modified Cam clay model shows considerably different rates and magnitudes of settlement, and different pore pressure behavior during the consolidation process.


Article
Axisymmetric Dynamic Behaviour of Thin Oblate Shells

Loading...
Loading...
Abstract

This paper presents a theoretical investigation of the axisymmetric free vibrations of an isotropic thin oblate spheroid shell. The analysis depends on the Rayliegh – Ritz's method. The non – shallow shell theory is used for the analysis. The analysis based on considering the oblate spheroid as a continuous system constructed from two spherical shell elements matched at the continuous boundaries. Throughout the results, it is shown that when the eccentricity reaches zero, an exact thin sphere solution is emerged and when the eccentricity equals one an exact thin circular plate solution is emerged. Therefore, the eccentricity of an oblate shell at medium value lies between these two values. It was found that the Rayleigh – Ritz's method is suitable for all eccentricities, while the literature showed that the Rayleigh's method is suitable for eccentricities less than 0.6.


Article
Modeling of Induction Heating Process of a Conducting Ferromagnetic Materials

Loading...
Loading...
Abstract

This research deals with a modeling of the heating process of an induction furnace with a conducting ferromagnetic core. This is done by performing a sequential coupling between two types of analysis; the harmonic electromagnetic analysis and the transient thermal analysis in order to furnish a complete numerical simulation of this device. The time elapsed to apply this procedure will be too long and unreasonable because of the consideration of the nonlinearity of the magnetic circuit. This problem is solved by the idea of the "Effective Relative Permeability", which is a constant relative permeability equivalent to the nonlinear one in calculating the eddy current losses. The Finite Element Method (FEM) is considered in order to solve this problem using the "ANSYS "computer package. An efficient coupling program deals with heat treatment procedure for any axi-symmetrical non-linear work piece has been built. The obtained results show a good agreement with the published practical measurements. This algorithm is a computer aided design for a nonlinear induction furnace with rotational symmetry, hence it can be used to design such devices instead of the traditional trial and error, experience dependant, design methods which lead to a costly and time wasting design.

Keywords


Article
Water Coning in Asmary Reservoir-Fauqi Field

Authors: Shaker M. Khalaf --- Talib A. Saleh
Pages: 4339 -4346
Loading...
Loading...
Abstract

Water coning in oil wells is one of the most serious problem because when the water reach to perforated zone, it will be produced with oil. Water with oil will form other problems in refinery, such as corrosion, and it will affect the purity of different petroleum products. The present work deals with fauqi field Asmari reservoir which is an active water drive reservoir. An empirical equation has been proposed to calculate the critical production rate. This equation is obtained by regression of the data which are collected from Missan oil field. The proposed equation gives better results than Schools and Myer equations when compared with the actual production rate.

Keywords


Article
New Correlation for Oil Formation Volume Factor at and Below Bubble Point Pressure

Authors: Dhefaf J. Sadiq --- Omar F. Hassn
Pages: 4347 -4355
Loading...
Loading...
Abstract

The best source of oil properties data is the laboratory PVT analysis of a reservoir fluid sample. However, in the absence of experimentally measured properties of reservoir fluids, these physical properties must be estimated from correlations. This paper employs more than thirty PVT reports that have been taken from different Iraqi fields. These reports contain about four hundred experimental points. The paper suggests new correlation to calculate oil formation volume factor at and below bubble point pressure. All of the previous correlations did not take the pressure as a factor or independent variable because they calculate the oil formation volume factor at bubble point pressure only. The new correlation introduce the pressure while omit the solution gas-oil ratio which has been employed in all previous correlations. The accuracy of the proposed correlation of the experimental data is assessed through various statistical tests and comparing them with those achieved for some published correlations. These tests show that the new correlation has the best fitting with the experimental data for Iraqi oils. Cross plot technique is also applied to check the performance of the correlation and it gave the same index of the statistical criteria method. The new correlation reported absolute average error of 1.876%, sum of squared residuals of 0.395327, variance of 0.0093 and standard deviation error of 0.096337288.


Article
Treatment of Industrial Waste Water using Reverse Osmosis Technique

Authors: Rasha H. Salman --- Sama M. Abdullah --- Nada S.Ahmedzeki
Pages: 4356-4363
Loading...
Loading...
Abstract

Reverse osmosis technique was used for the treatment of industrial waste water. Ions like calcium, magnesium, sodium, sulfate, and nitrate were found in the waste water of the General Company of Vegetable Oil with high concentrations which must be treated for reuse. Feed water containing the above mentioned ions was fed to the RO unit at feed flow rates (0.4 and 0.8 lit/min) and different operating pressure (2-4bar) .It is concluded that increasing operating pressure and feed flow rate improved the separation by a decrease in the concentration of ions in the product. High rejection was obtained for all ions present in feed water, ranging from (63.8-97.6%). Rejection of TDS was 87% when the concentration of TDS was reduced from 1192 to 154.94 ppm.

Keywords


Article
Development of a LAN Simulation Tool Based on Windows Environment

Authors: Wisam F. Kadhim --- Nidhal Ezzat --- Hamid M. Ali
Pages: 4364 -4377
Loading...
Loading...
Abstract

The Internet’s rapid growth has spurred the development of new protocols and algorithms to meet changing operational requirements such as security, multicast transport, mobile networking, policy management, and quality of service support. Development and evaluation of these operational tools requires answering many design questions. This work proposes a computer network simulation program, devoted for wired LAN systems. The simulator would be able to work under Microsoft Windows NT platforms, also it has the potential to provide an emulation environment which should be suitable for testing protocols above the TCP layer under the Windows NT platform supported network layers, and offering scalability by running the simulator under distributed network system.


Article
Effect of ZRO2 , WO3 Additives on Catalytic Performance of PT/HY Zeolite Compared with PT/Γ-AL2O3 For Iraqi Naphtha Transformation

Authors: Maha Al-Hassany
Pages: 4378 -4392
Loading...
Loading...
Abstract

Light naphtha treatment was achieved over 0.3wt%Pt loaded-alumina, HY-zeolite and Zr/W/HY-zeolite catalysts at temperature rang of 240-370°C, hydrogen to hydrocarbon mole ratio of 1-4 0.75-3 wt/wt/hr, liquid hourly space velocity (LHSV) and at atmospheric pressure. The hydroconversion of light naphtha over Pt loaded catalyst shows two main reactions; hydrocracking and hydroisomerization reactions. The catalytic conversion of a light naphtha is greatly influenced by reaction temperature, LHSV, and catalyst function. Naphtha transformation (hyroisomerization, cracking and aromatization) increases with decreasing LHSV and increasing temperature except hydroisomerization activity increases with increasing of temperature till 300°C then began to decrease due to the formation of hydrocracking reaction. The investigation of Pt containing catalysts under study shows a very high hydrogenlysis activity , due to presence of metal component (i.e. Zr, W) which enhances the rate of paraffin isomerization and cracking.The hyroisomerization and the hydrocraking activities can be arranged as follows,. Pt/Zr/W/HY > Pt/HY > Pt/γ-Al2O3 The results showed that, Pt/γ-Al2O3 has higher activity for the direct dehydrogenation of C6 and C7 paraffin's present in naphtha to aromatics than Pt/HY and Pt/Zr/W/HY. This was due to pore volume catalyst ,the aromatics compounds increased as the pore volume increased.

Keywords


Article
The Effect of Self-EquiIibrating Stresses due to Multi-Line Spot Welded Stiffeners on the Natural Frequencies of Plate

Authors: Sahar M. Saliman --- Kareem N. Salloomi --- Faiz F. Mustafa
Pages: 4393-4408
Loading...
Loading...
Abstract

In this paper an investigation has been made into the effect of residual stresses on the vibration characteristics of a thin rectangular stainless steel plate with multi-line spot welded stiffeners. A new general frequency equation with and without the effect of residual stresses due to multi-line spot welding along the length and width of the plate for different boundary conditions were obtained. The results give that the free ends tries to increase the natural frequencies while the clamped edges try to decrease the natural frequencies; also the central position weld line has the great influence on the natural frequencies.


Article
Some Properties of High Performance Carbon Fibres Cement Composites
بعض خواص الخرسانة عالية الأداء المسلحة بألياف الكاربون

Authors: Nada Al – Jalawi
Pages: 4409 -4416
Loading...
Loading...
Abstract

The paper presents properties of high performance concrete reinforced with relatively high percentage of choped carbon fibers vol. fraction ranging from (1 to 5) %. The great advantage of such composites is their relatively high flexural strength. A low water to cement ratio of 0.3 with super plasticizer was used in order to keep the cement mix easily workable. To improve the properties, a locally existing pozzolan based on reactive meta- kaolin was used in the mixture together with silica sand. A high modulus carbon fibers (450 KN/mm2) were also used. In addition to the flexural strength, dynamic modulus of elastisity were found using dynamic methods. The results showed that the specimen failed in flexureal by a single crack although the ultimate tensile strength and the stiffness of the composite were increased as the fibers content was increased.


Article
Bearing Capacity of Shallow Footing on Soft Clay Improved by Compacted Cement Dust

Loading...
Loading...
Abstract

Low bearing capacity of weak soil under shallow footings represents one of construction problems. Kaolin with water content converges to liquid limit used to represent the weak soil under shallow footing prototype. On the other hand, cement dust, which can be defined as undesirable industrial waste material come from cement industry, was used to improve the bearing capacity of the soft soil considered in this research. The soft soil was prepared in steel box (36×36×25) cm and shallow square footing prototype (6×6) cm were used .Group of physical and chemical tests were conducted on kaolin and cement dust. The improvement were performed by making trench under the footing filled with compacted cement dust (at its optimum moisture content) at three depths (D=B, D=2B, D=3B), the trench had the same footing Dimensions, note that (B) represent the footing width. Pressure-settlement curves were used to predict the ultimate bearing capacity. The improvement ratio in bearing capacity was calculated by comparing the ultimate bearing capacity value when testing the kaolin alone with its value of kaolin improved with compacted cement dust at the same value of eccentricity. It is important to note that eccentricity values were chosen according to the rule of middle third of footing base(i.e.,e≤B/6). The improvement ratio was about (197%) in average value, that represent a good ratio of improvement.


Article
Assessment of Phenol Derivatives in Cooling Tower System as Biocides

Loading...
Loading...
Abstract

One of the major problems facing the industrial utilities especially cooling towers is biofouling. Many techniques and measures have been taken and still continuing researches are under way. Biocides and water qualities were the main area of research for evaluation. Friendly biocides are preferable for controlling viable count and fungi, but many harmful still in use. The main objective of this research work is to predict a relationship covering the concentration of Cl and Br – containing compounds as biocide and the performance. It was concluded that the chlorophenol is the major effective biocide used (reduce it for about 80%, while bromophenol to about 65%) and that material although they are highly approved, but suffer pitting corrosion.


Article
Study on Absorption of Ozone in Water Using Perforated Sieve Tray Column
دراسة امتصاص الاوزون بالماء في برج امتصاص ذو صواني مثقبة

Loading...
Loading...
Abstract

The aim of this work is concerned with detailed study of transfer of ozone into water.. Since ozone cannot be stored or conveniently purchased by the gram, pound, gallon or ton, it must be produced on site as needed, (where needed and when needed). The process will carried out with two important assumptions; first that ozone is the only active species that physically dissolves in water. And second that there is no chemical reaction .the process carried out in a perforated sieve tray column with 1 m long and 33 cm diameter. The effects of process variables such as (Water flow rate, pH and air flow rate which is refer to the concentration of free ozone in the gas phase in the absorption column). The result show that the absorption rate increases with increasing the water flow rate and decreasing the air flow rate in a pH range (7-8).

Keywords


Article
The Effect of Coarse Aggregate Ratio on the Properties of No Fine Light Weight Concrete
تاثير نسبة الركام الخشن على خواص الخرسانة الخالية من الركام الناعم

Authors: Luma Abdul. Ghani. Zghair --- Hind.H. HAMAD
Pages: 4447 -4462
Loading...
Loading...
Abstract

The main object of this work is to study the effect of coarse aggregate/cement ratio (A/C) on the property of no fine concrete. In this work, three ratio of A/C were used (6, 9 and 12 by weight).The cement content is maintained constant (125kg/m3) while the w/c ratio ranges from (0.39 to 0.55 by weight). Tests are carried out on hardened concrete to investigate the effect of coarse aggregate/cement ratio on the compressive strength, absorption%, density, porosity%, ultrasonic pulse velocity, acoustic impedance of mixes. The results showed that increasing the percentage of A/C ratio by weight from 6 to 12 for the used mixes reduces the compressive strength, ultrasonic pulse velocity and acoustic impedance, on the other hand the porosity and the absorption percentage, increase with increasing ratio of A/C for all studied mixes. At 28 days the compressive strength , ultrasonic pulse velocity and acoustic impedance tests with A/C ratio of (12) are (2.8.MPa), (2km/sec) and (3×106 Kg/(sec.m2)) respectively while decreasing the ratio to (6) improves these properties to (9.3MPa), (3km/sec) and ( 5.7 ×106 Kg/(sec.m2)) respectively On the other hand the porosity and the absorption % decrease with decreasing the ratio of A/C for all studied mixes . At 28 days the porosity and the absorption % with A/C ratio of (12) are (40%) and (2.7%) respectively with decreasing the ratio to 6 decrease these properties to (19%) and (1%) respectively. The densities of the mixes were tested. At 28 days the density with A/C ratio of (12) are (1512 kg/m3 )with decreasing the ratio to 6 increase the density to(1907 kg/m3 ) Based on the analysis of experimental results, several graphs and tables have been prepared to study the properties of no fine concrete.

Table of content: volume: issue: