ISSN: 1997-9428

Issue 1,

Issue 1

Thermal Stresses Distribution Induced in a Chimney Shell Structure of a Power Plant

Khalid J. Al-Horan

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 1-10

In The present work, a thermal analysis of two different chimneys by studying the effect of the flue gases on the chimney shell structure was presented. A computer program was constructing using Fortran language to estimate the thermal stresses that: radial, circumferential and longitudinal thermal stresses which will induced as a result of thermal gradient across the chimney wall structure.
The results show, the radial thermal stresses has the minimum value at the middle of the concrete layer in the unlined chimney. The circumferential and longitudinal thermal stresses are transferred from the negative value to the positive value. The maximum value of stresses is found in the inner surface negative value and on the outer surface positive value of the chimney.

Key Exchange Protocol Supporting Mobility and Multihoming

Abdul-Karim A-R. Kadhim; Sufyan T. Faraj; Mohammed A. Tawfiq

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 11-30

In this work, a new key exchange protocol for IP-based mobile networks is introduced. This protocol is called KEPSOM (Key Exchange Protocol Supporting Mobility and Multihoming). The goals of designing KEPSOM are to develop key exchange protocol proposal characterized by its secrecy, simplicity, efficiency, resistivity, and its ability to support mobility and multihoming. The protocol requires only two roundtrips. The design limits the private information revealed by the initiator. An old security association (SA) can be replaced with a new one by rekeying without the need of restarting the protocol with a new session. On the other hand, the changes in IP address due to mobility or multihoming need not to restart the protocol with a new SA session. The proposed protocol can also support key exchange in hybrid wireless network, in which the mobile node can operate in both Ad Hoc and Base Station-oriented wireless network environments using different transmission modes. KEPSOM has been analyzed and proven secure. Several tests have been done to measure and evaluate the performance of the protocol. In these tests, it is found that the required time for rekeying is about 27% of the total required time for exchanging the keys. And the required time to detect and update the change in IP address, which may occur due to mobility or multihoming, is less than 10% of the total required time to establish a new SA sessions.

Effect of Delta–Winglet Vortex Generators on a Forced Convection Heat Transfer in an Asymmetrically Heated Triangular Duct

Hamid E.Zangana; Adnan A. Abdul-Rassol; Mohanad A. Al-Taher

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 31-44

An experimental investigation is performed to study the friction factor ( f ) and convection heat transfer coefficient (h) behavior in an asymmetrically heated equilateral triangular duct by using delta–winglets vortex generators which are embedded in a turbulent boundary layer. Two side walls of the heated test section are electrically heated with a constant heat flux, whereas the lower wall is indirectly heated. Reynolds number (Re) is ranged from (23,000) to (58,000). Two sizes and three attack angles of vortex generators are studied here for three cases; single, double, and treble pairs of generators. Each pair was supported in one wall of the test section at the various locations from the leading edge. The indicated results that friction factor ( f )and Nusselt number (Nu) are relatively proportion with the size, number and the inclination angle of the generators. The ( f ) decreases as airflow rate increases whereas Nu number increases. The present data of ( f ) is less than the data of Chegini by about (6.5 %) and overpredicts the data of Altemani by about (1.7 %).

Image Compression Using Vector Quantization and Genetic Algorithms

Salah Awad Salman

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 45-58

Image compression involves reducing the size of image data file, while retaining necessary information.This paper uses the facilities of the Genetic Algorithm for the enhancement of the performance of one of the popular compression method, Vector Quantization method is selected in this work. After studying this method, new proposed algorithm for mixing the Genetic Algorithm with this method was constructed and then the required programs for testing this algorithm was written. The proposed algorithm was tested by applying it on some image data files. Some fidelity measures are calculated to evaluate the performance of the new proposed algorithm. A good enhancement was recorded for the performance of the Vector Quantization method when mixed with the Genetic Algorithm. All programs were written by using Matlab (version 7.0) and these programs were executed on the Pentium III (866 MHz) personal computer.

Unconditionally Secure Authentication in Quantum Key Distribution

Sufyan T. Faraj

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 59-76

Quantum key distribution (QKD) is a method using some properties of quantum mechanics to create a secret shared cryptographic key even if an eavesdropper has access to unlimited computational power. All QKD protocols require that the parties have access to an authentic channel. Otherwise, QKD is vulnerable to man-in-the-middle attacks. This paper studies QKD from this point of view, emphasizing the necessity and sufficiency of using unconditionally secure authentication in QKD. In this work, a new technique of using unconditionally secure authentication is proposed for quantum cryptosystems. This technique is based on a hybrid of normal application of authentication codes and the so-called “counter-based” authentication method such that to achieve a better trade off between security and efficiency (in terms of the required size of initially shared secret data). Based on this strategy, an authenticated version of a typical QKD protocol (the well-known BB84 protocol) is described. Some advantages of our protocol in comparison to other proposals are also highlighted.

On the Effect of Flow Direction on Mixed Convection from a Horizontal Cylinder in a Saturated Porous Medium

Mohammed A. Ahmed

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 77-87

A numerical investigation of mixed convection from a horizontal cylinder in a saturated porous medium is presented. The governing equations based on Darcy’s law are expressed in a body- fitted coordinate system and solved numerically by explicit method. The direction of the flow varies between the vertically up ward(assisting flow) and vertically downward(opposing flow). Results are presented for Reynolds number Re from 10 to 100 with Grashof numbers up to Gr =5Re. The Prandtl number was kept at a constant value of 0.7. results are presented for the streamlines and isotherms as well as the local and average Nusselt number at different values of governing parameters. Comparison with previous theoretical results show good agreement.

Effect of Admixture Type on Compressive Strength and Modulus of Elasticity of Rubber- Tire - Waste Concrete

Khalid Battal Najim

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 88-103

The presented work investigates the effect of addition admixtures (superplasticizer and polymer) to Chopped Worn-Out Tire concrete as a partial replacement of cement weight. Superpasticizer was addition by 4% and polymer (SBR) by 15%. The Chopped Worn-Out Tire (Ch.W.T.) addition to reference concrete with the three proportions as a Partial Replacement Ratio (PRR) of (25,25),(20,30),and (30,20) by volume of (sand and gravel) respectively. Three mixes were selected with above PRR for each type of admixture in additional to three mixes for Ch.W.T. concrete without admixtures and three reference mixes with admixtures without Ch.W.T. Thus, twelve mixes could be used in this investigation. Compressive strength and modulus of elasticity (static and dynamic) were tested. The test results indicated that the use of admixture led to significant improvement in concrete properties in general. Superplasticizer gave best results comparative with polymer, for example at 28 day the compressive strength of superplasticizer Ch.W.T. concrete Csp25,25 was 32.5 MPa, while compressive strength of polymer modified Ch.W.T. concrete CB25,25 was 28 MPa and compressive strength of Ch.W.T. concrete C25,25 was 21.2 MPa.

Effect of Strain Rate on Tensile Fracture Behaviour of Viscoelastic Matrix (EPOXY) and Fiber Reinforced Composites

Saad Mohamed Jaleel; Arz Yahya Rzayeg; Mashaan Ibrahem Hassan

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 104-115

Viscoelasticity, as its name implies, is a generalization of elasticity and viscosity. Many industrial applications use viscoelastic matrix with reinforcement fiber to obtained better properties. Tensile testing of matrix and one types of fabric polyamide composites was performed at various loading rates ranging from (8.16* 10-5 to 11.66 * 10-5 m/sec) using a servohydraulic testing apparatus. The kind of reinforcement, random glass fiber (RGF), and the kind of matrix, epoxy (E) are used shown that the linear strain (،ـ 0.5) for the three parameter model gives a good agreement with experimental results. The results showed that both tensile strength and failure strain of these matrices and composites tend to decrease with increase of strain rate. The experimental results were comparison with numerical results by using ANSYS 5.4 program for simple study case has shown some agreement. Fracture regions of the tested specimens were also observed to study micro mechanisms of tensile failure.

Modeling and Performance of a Wind Turbine

Wissam Hashim Khalil

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 116-130

The dynamics of wind turbine has to be studied carefully to avoid unpredictable outputs and to make sure that consistent and efficient power is supplied according to the load requirements. There is a great and urgent necessity to increase the efforts in the development of the researches of the renewable energy to decrease the dependency on the conventional ones. The objective of this research is to make a contribution to the ongoing wind turbine research in the area of modeling, which is the first step required for the control and implementation of wind turbines. The wind turbine transfer function is derived and its performance has been established using the MATHLAB Software. This research provided a different approach to wind turbine modeling methodology. The results of this research may be used in another step for completing the control process of the wind turbine.

The Effect of the Hollow Ratio on the Natural Convection Heat Transfer from Upward Heated Plates at Constant Heat Flux

Arz Yahya Rzayeg; Saad Mohamed Jaleel; Mashaan Ibrahem Hassan

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 131-142

The present research studies experimentally the effect of the ratio of the centurial hollow on the average of laminar convective heat transfer and the thermal gradation of the thermal boundary layer of three square flat plates. An experimental set-up was made for this purpose containing basically three uniformly Aluminum flat plates of a centurial hollow representing (0.25,0.5,0.75) of the entire surface area of each plate. Each of the three plates were heated by a constant heat flux for a rang of Rayleigh number of (5.62x105≤Ra≤1.67x106).The study showed that increasing the hollow ratio causes to increase the average of convective heat transfer by increasing the average Nusselt number, and the increasing average from a ratio to another decreases by the increases of the hollow ratio. The increasing between the two surfaces at (m=0.25&m=0.5) reached (39.6%) and for (m=0.5&m=0.75) was less than that and reached (29.2%).The increase average between the biggest and smallest hollow ratio was (78%).The study also showed that the maximum thermal gradation was on the out side edge of the plates and increases with the increase of Rayleigh number and the hollow ratio.

Study of Quality Control of A Survey Work in Construction Projects Case Study ( AL Rahman Mosque)

Khmis N. Sayle; Ibrahim A. Al- Janabi

Anbar Journal for Engineering Sciences, 2008, Volume 1, Issue 1, Pages 143-159

Recently our country is witnessed an implementation of many construction with high stories . thus , the accuracy of implementation and monitoring of survey works should be consider . in this paper quality control in survey works in AL-RAHMAN Mosque were studied as a case study .
The magnitude and correlation of errors are importance to the design stage, measuring and adjustment development .in the design stage the study of errors is very important to provide us the basic chose of fingers , selection of instrument types, and proper procedures to get the specified accuracy , in the measuring sate the stud of errors is an important because it give us acceptation or rejection limitation in the site. In the adjustment operation the study of errors give us an increment in can riddance level the result of present paper indicated that there are conclusion and recommendation should be considered to accept or reject in future works.