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: 2016 volume:22 issue:12

Article
Behavior of Reinforced Concrete Continuous Beams under Pure Torsion
سلوك العتبات الخرسانية المسلحةوالمستمرة تحت تأثيرعزوم أللي الصرفة

Loading...
Loading...
Abstract

Practically, torsion is normally combined with flexure and shear actions. Even though, the behavior of reinforced concrete continuous beams under pure torsion is investigated in this study. It was performed on four RC continuous beams under pure torsion. In order to produce torsional moment on the external supports, an eccentric load was applied at various distances from the longitudinal axis of the RC beams until failure. Variables considered in this study are absolute vertical displacement of the external supports, torsional moment’s capacity, angle of twist and first cracks occurrences. According to experimental results; when load eccentricity increased from 30cm to 60cm, the absolute vertical displacement increased about 46.92% and the angle of twist increased about 45.76% at failure. It has been also found that the ultimate failure loads decreased about 49.65% when the load eccentricity increased from 30cm to 60cm. Furthermore, the first crack was monitored and it was found that the first crack occurred at higher stages of loading with low loading eccentricity. The first crack records appeared at 75.86%, 70.80%, 63.16% and 54.79% of loading when the load eccentricities are 30, 40, 50 and 60cm, respectively.


Article
Improvement of Shear Strength of Sandy Soil by Cement Grout with Fly Ash
تحسين مقاومة القص للترب الرملية باستخدام الحقن بالاسمنت و الغبار المتطاير

Loading...
Loading...
Abstract

The effects of the permeation cement grout with fly ash on the sandy soil skeleton were studied in the present work in two phase; first phase the shear strength parameters, and the second phase effect of these grouted materials on volume grouted zone by injection (51) cm³ of slurry in sandy soil placed in steel cylinder model with dimension 15 cm in diameter and 30 cm in height. The soil sample was obtained from Karbala city and it is classified as poorly graded sand (SP) according to USCS. The soil samples were improved by cement grout with three percentages weight of water cement ratio (w:c); (0.1w:0.9c, 0.8w:0.2c, and 0.7w:0.3c), while the soil samples were dehydrated for one day curing time. Fly ash class (F) was used with cement grout as filler material; it was added to the mixture as a replacement material for cement in weight percentages; 10%, 25% and 40%. According to the results of tests, both shear strength and approximate volume of the effective grouted zone for treated samples soil with cement grout was increased when the water cement ratio decreased. Fly ash with cement grout needs to increase the water demand for the grout mixing to give best results in both shear strength and filling the soil voids.


Article
Numerical and Experimental Investigations of the Effect of PVD and Vacuum Pressure on the Degree of Saturation
تحليل نظري وعملي لتأثير أعمدة الصرف الطولية وضغط التفريغ على درجة التشبع

Loading...
Loading...
Abstract

Soft clays are generally characterized by low shear strength, low permeability and high compressibility. An effective method to accelerate consolidation of such soils is to use vertical drains along with vacuum preloading to encourage radial flow of water. In this research numerical modeling of prefabricated vertical drains with vacuum pressure was done to investigate the effect of using vertical drains together with vacuum pressure on the degree of saturation of fully and saturated-unsaturated soft soils. Laboratory experiments were conducted by using a specially-designed large consolidometer cell where a central drain was installed and vacuum pressure was applied. All tests were conducted with a vacuum pressure of 40 kPa applied for a period of 30 days where a degree of soil consolidation of 90% was attained. At the end of the test period fifteen samples were taken from different locations distributed along the depth and radially to measure the water content. Consolidation settlements were recorded with time for all tests. The results showed that using vacuum pressure with vertical drains is a very effective method to accelerate consolidation of soils. As the thickness of unsaturated top layer increases, the settlement of soil surface decreases. The water content decreased after 30 days of application of the vacuum pressure.


Article
A Laboratory Study Attempt of Flow and Energy Dissipation in Stepped Spillways
محاولة دراسة مختبرية للجريان و الطاقة المتشتتة في المطافح المدرجة

Loading...
Loading...
Abstract

A 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 stepped without any addition, and the last one was stepped with cavitation. The height of stepped spillways was 18 cm with unique numbers of steps (n = 3), and unique downstream slope of stepped face (θ =30⁰) were utilized. The percentage of relative energy dissipation (R.E.D) was increased using rough surface with coarse gravel. When the size of gravel increased, the R.E.D was increased and when using the ratio between heights of gravel to steps of 0.5, the R.E.D was increased to about triple compared with traditional spillways. The R.E.D was decreased when the cavitation on the stepped surface was utilized compared to the stepped spillway without any addition for large discharges and that was inverse for small discharges. Comparing to steps without any addition, the rouged steps with the larger size of gravel maximized the energy dissipation for both small and large discharges. The relative energy dissipation was 26.73 % compared with traditional spillway and 16.73 % compared with stepped spillway without any addition, since the stepped spillways more effective than traditional spillways by 10 %. In general, the R.E.D was decreased when increasing the discharge.


Article
A Hybrid Coefficient Decimation- Interpolation Based Reconfigurable Low Complexity Filter Bank for Cognitive Radio
مجموعة مرشحات قائمة على هجين من معامل الهلاك ومعامل الاستيفاء المعاد تشكيلها والمنخفضة التعقيد

Loading...
Loading...
Abstract

Non uniform channelization is a crucial task in cognitive radio receivers for obtaining separate channels from the digitized wideband input signal at different intervals of time. The two main requirements in the channelizer are reconfigurability and low complexity. In this paper, a reconfigurable architecture based on a combination of Improved Coefficient Decimation Method (ICDM) and Coefficient Interpolation Method (CIM) is proposed. The proposed Hybrid Coefficient Decimation-Interpolation Method (HCDIM) based filter bank (FB) is able to realize the same number of channels realized using (ICDM) but with a maximum decimation factor divided by the interpolation factor (L), which leads to less deterioration in stop band attenuation (SA). The proposed architecture is able to realize a greater number of sub-bands locations. The proposed (HCDIM) based (FB) shows an inherent low complexity offered by the (CIM) technique when compared with the alternative FBs. The reduction in the number of multiplications is by 50.77% compared with ICDM in non-uniform channelization, while the reduction in the number of multiplications is about 59.64% over the discrete Fourier transform (DFTFB) and 31.19% over ICDM based FB in uniform channelization.


Article
Evaluating the Recharge of Ground Water within Al-Wand River Basin.
تقييم تغذية المياه الجوفية لحوض نهر الوند

Loading...
Loading...
Abstract

The estimation of recharge to ground water is the important basics to improve the use of ground water with other available resources, and to save ground water resource from depletion, especially when using large quantity of ground water during a long time such as for agricultural purposes. Al-Wand River Basin in Iraq suffers from water shortage of its requirement of Blajo–Al-Wand Project, and to cover this shortage, the ground water plays a good role to overcome this problem. In this study, three methods were used to estimate the recharge and ground water storage for Al-Wand Basin, these methods are: Water Table Fluctuation (WTF), Water Balance of Climatic for Basin, and Water Table Balance for Basin. The results showed differences between the methods used to estimate recharging and ground storage for this basin. The approximated values between drawl water from production wells and water balance of climate for basin method make it better the other methods, which the difference percentage was large with drawls water. Also, classifying the methods by assumptions found make (WTF) better method, because it contains less assumptions compared to the other methods.


Article
Experimental Investigation of Natural Convection into a Horizontal Annular Tube with Porous Medium Effects
تقصي عملي للحمل الطبيعي داخل أنبوب حلقي أفقي مع تأثير الوسط المسامي

Loading...
Loading...
Abstract

n this work, an experimental investigation has been done for heat transfer by natural-convection through a horizontal concentric annulus with porous media effects. The porous structure in gap spacing consists of a glass balls and replaced by plastic (PVC) balls with different sizes. The outer surface of outer tube is isothermally cooled while the outer surface of inner tube is heated with constant heat flux condition. The inner tube is heated with different supplied electrical power levels. Four different radius ratios of annulus are used. The effects of porous media material, particles size and annulus radius ratio on heat dissipation in terms of average Nusselt number have been analyzed. The experimental results show that the average Nusselt number increases with increasing annulus radius ratio and particle diameter for same porous media material. Furthermore, two empirical correlations of average Nusselt number with average Rayleigh number for glass and PVC particles are developed. The present experimental results are compared with previously works and good correspondence is showed.


Article
Analytical and Experimental Investigation for the Effect of Air Injection Angle on the Performance of Airlift Pump
دراسة تحليلية وعملية حول تأثير زاوية حقن الهواء على أداء مضخات الرفع الهوائية

Loading...
Loading...
Abstract

The effect of air injection angle on the performance of airlift pump used for water pumping has been studied analytically and experimentally. An airlift pump of dimensions 42mm diameter and 2200 mm length with conventional and modified air injection device was considered. A modification on conventional injection device (normal air-jacket type) was carried out by changing injection angle from 90° (for conventional) to 45° and 22.5° (for modified). Continuity and one-dimensional momentum balance for the flow field with basic principle of two-phase flow and expressions of slip ratio and friction factor as function of flow rates were formulated. The analytical and experimental investigations were carried out for both conventional and unconventional air-jackets at submergence ratios 0.75, 0.6 and 0.5 and air mass flow rate from 0.5 to 97kg/hr. The comparison between the analytical and experimental results shows agreement and the main results showed that the performance and maximum efficiency of airlift pump is increased for higher mass flow rate of injected air for all tested submergence ratio using unconventional air-jacket and the higher performance was associated with injection angle 22.5°, with average enhancement were 9% and 10% for performance and maximum efficiency respectively.


Article
Robustness Assessment of Regional GNSS Geodetic Networks for Precise Applications
تقييم متانة الشبكات الجيوديسية (GNSS) للتطبيقات الدقيقة

Loading...
Loading...
Abstract

Over the past few decades, the surveying fieldworks were usually carried out based on classical positioning methods for establishing horizontal and vertical geodetic networks. However, these conventional positioning techniques have many drawbacks such as time-consuming, too costly, and require massive effort. Thus, the Global Navigation Satellite System (GNSS) has been invented to fulfill the quickness, increase the accuracy, and overcome all the difficulties inherent in almost every surveying fieldwork. This research assesses the accuracy of local geodetic networks using different Global Navigation Satellite System (GNSS) techniques, such as Static, Precise Point Positioning, Post Processing Kinematic, Session method, and finally Real Time Kinematic for different surveying applications. To achieve this assessment, GNSS observations were executed to highlight the characteristics for each GNSS observation technique. Furthermore, the level of accuracy which is gained from each positioning technique is enormously investigated to figure out the amount of allowable error and the suitability for different geodetic applications. In relative positioning, at least two receivers (or more) are required for timing and positioning while the Precise Point Positioning necessitates single receiver. Some of geodetic applications require about positions with centimeter level of accuracy or less. The robust geodetic networks provide accurate positions which in turn serve different earth science applications.

Table of content: volume: issue: