Articles in This Issue
Abstract
أصبح استخدام میاه مالحة فی الری أمرا مألوفا منذ نحو خمسین عاما حیث تتوفر تلک المیاه فی کثیر من البلدان الفقیرة بالموارد المائیة المتجددة . تناول هذا البحث دراسة تأثیر نسبة الأمطار الفعالة واحتیاجات الغسل (leaching requirements) على إنتاجیة أربعة محاصیل إستراتیجیة عند إروائها بمیاه متوسطة الملوحة من مصدرین مختلفین , حیث تم اعتماد میاه جوفیة من بئرین یبلغ ترکیزهما الملحی 5.43 دسی سیمنز / م , و 8.39 دسی سیمنز / م . تم بناء برنامج حاسوب لتخمین إنتاجیة القمح والشعیر والذرة والقطن عند إروائها بکل من المصدرین المائیین المذکورین تحت ثلاث نسب من احتیاجات الغسل ولأربع حالات من نسب الأمطار الفعالة . لوحظ ارتباط إنتاجیة المحاصیل بعلاقة خطیة مع نسب الأمطار الفعالة , وعلاقات لا خطیة مع احتیاجات الغسل , وقد تناول البحث تفسیر تلک العلاقات .
Abstract
Abstract In this study the hydraulic performance of single step broad-crested weir was improved. Through analyzing the parameters that have effect on the shape of the step and its influence on the flow characteristics, and energy dissipation percent (E%) downstream (D/S) of the weir. The differential equation of gradually varied flow for the water surface profile over the weir was solved analytically .Furthermore, empirical relations for E% and discharge coefficient (Cd) due to the affecting factors were derived .The results showed that the weir model when the ratio of the length of D/S step to the length of the weir L2/L1=0.5 gives a higher E% in comparison with other weir models. Three types of flow regimes were observed, nappe flow below 350 cm3 /s/cm, transition flow 350-700 cm3/s/cm and skimming flow upper than 700 cm3/s/cm . The comparison between calculated values by the differential equation of gradually varied flow and experimental values gives a good agreement, the maximum difference is about 7%.Two empirical relations were obtained, the first to estimate Cd in terms of the ratio for upstream U/S water head to U/S weir height H/P1 and L2/L1. While the second relation to estimate E% in terms of the ratio for D/S water head to U/S weir height h/P1, L2/L1 and the Froude number Fr2 with a high correlation coefficient . Key words: Hydraulics; weirs ; performance ; dissipation energy.
Abstract
الخلاصة (Abstract):إن الغرض من الدراسة هو الوصول إلى أفضل سیاسة تشغیل شهریة مثلى لخزان سد الموصل لفترة زمنیة أمدها 35 سنة للحصول على اقل خسائر ممکنة نتیجة الشحة او الفیضان من جهة وتجاوز الخزین الحدود الدنیا والعلیا التشغیلیة من جهة أخرى وذلک باستخدام البرمجة الدینامکیة التفاضلیة المتقطعةDDDP)).استخدمت نتائج تلک الدراسة فی البحث عن أفضل توزیع احتمالی للخزین المستخرج وذلک باستخدام مختلف التوزیعات الاحتمالیة المتوفرة والتی تبین من خلالها إن التوزیع اللوغارتمی الطبیعی لمتغیرین هو أفضل هذه التوزیعات من اجل الحصول على منحنیات التشغیل ولمختلف الاحتمالات وکانت النتائج جیدة دون حصول تجاوز لأی من المحددات کما تم الإیفاء بکافة المتطلبات التی تم آخذها بنظر الاعتبار.الکلمات المفتاحیة : التشغیل الأمثل ، الاحتمالیة ، خزانات السدود .
Abstract
Chlorine is considered as one of the most important disinfectants because of its availability in a wide form and in acceptable cost. Measurements of residual chlorine are very essential to assure the presence of disinfection at various locations of the water distribution system. The aim of the present work is to find the residual chlorine concentrations in potable water which leaves Tikrit University water supply plants. pH-, water temperature and water turbidity are also measured. Sixty samples of tap water are tested during November 2009 till April 2010. The results show that range of residual chlorine is 0.2-4mg/l) and most of the measured values are higher than the maximum permissible limit according to Iraqi standards( 417/1974 ) The data indicated that pH is within the range of (7-8.2) and there is no clear relationship between pH and residual chlorine concentration. It is found that there an inverse proportionality between residual chlorinean and temperature . Same trend is found between residual chlorine and turbitiy. The Conductivity and total dissolved solid of drinking water was within the permitted level by the Iraqi standers
Abstract
Abstract. In this research, Artificial Neural Networks (ANNs) will be used in an attempt to predict collapse potential of gypseous soils. Two models are built one for collapse potential obtained by single oedemeter test and the other is for collapse potential obtained by double oedemeter test. A database of laboratory measurements for collapse potential is used. Six parameters are considered to have the most significant impact on the magnitude of collapse potential and are being used as an input to the models. These include the Gypsum content, Initial void ratio, Total unit weight, Initial water content, Dry unit weight, Soaking pressure. The output model will be the corresponding collapse potential. Multi-layer perceptron trainings using back propagation algorithm are used in this work. A number of issues in relation to ANN construction such as the effect of ANN geometry and internal parameters on the performance of ANN models are investigated. Information on the relative importance of the factors affecting the collapse potential are presented and practical equations for prediction of collapse potential from single oedemeter test and double oedemeter test in gypseous soils are developed. It was found that ANNs have the ability to predict the collapse potential from single oedemeter test and double oedemeter test in gypseous soil samples with a good degree of accuracy. The ANN models developed to study the impact of the internal network parameters on model performance indicate that ANN performance is sensitive to the number of hidden layer nodes, momentum terms, learning rate, and transfer functions. The sensitivity analysis indicated that for the models the results indicate that the initial void ratio and gypsum content have the most significant affect on the predicted the collapse potential.Keywords. Artificial Neural Networks, collapse potential, gypseous soils
Abstract
Severe Shortage and bad quality of Surface water in the area of Diyala Bridge , added to the growing demand for drinking , irrigation and sanitary waters , leads to study and qualify the under ground water in this area , Six shallow wells has been selected to the east of Diyala river , five of them where on shore and the sixth was far away from river about ( 3 km) .The depth of these wells was (10- 14)m . Tests of ( Ph , TDS , BOD , Turbidity , Conductivity ,----etc) where performed during March , June, Aug. in 2008. Heavy metals such as ( Pd , Zn , Cd , Fe , Mn ) has been examined as well . Results of physical , chemical and bacteriological tests show that the water quality of these wells were not comply with WHO requirements ,as well as results show considerable increased concentrations in TDS,BOD and heavy metals which indicates that underground waters were highly polluted with the sanitary waste waters . On the other hand the on shore wells' water quality was very close to the river water quality in comparison with the well in the middle of the town.
Abstract
This study was determined specified characteristics of Iraqi silica sand , touse it in the drinking water treatment rapid gravity filters. These properties includes grain size ,uniformity coefficient , grain shape , porosity , density , durability, chemical content and capability of solubility in the acid ..this study explained that the Iraqi silica sand has high degree at mechanical and chemical stabilities .The e filter column was operate for many cycles , the average results of raw water and treatedwater for variable values (turbidity , total suspended solids and total bacterial count) was taken . The study showed that possibility of use the Iraqi silica sand in the westernIraqi desert in the rapid gravity drinking water treatment plant filters . when the raw water has initial turbidity (5.24 NTU) ,the study and the experimental tests showedthat the average removal efficiency of turbidity , T.S.S ,and T.B.C of (82.9%,82.8%and 79.5%) respectively . when the raw water has initial turbidity (9.58 NTU) ,the study and the experimental tests showed that the average removal efficiency of turbidity , T.S.S ,and T.B.C of (79.4%,78.7% and 74.1%) respectively . when the rawwater has initial turbidity (28.35 NTU) ,the study and the experimental tests showedthat the average removal efficiency of turbidity , T.S.S ,and T.B.C of (72.6%,72.7%and 60.9%) respectively
Abstract
AbstractIn this paper a nonlinear finite element analysis is presented to simulate the fire resistance of reinforced concrete slabs at elevated temperatures. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory with initial stiffness technique is employed. The proposed model considered cracking, crushing, and yielding of concrete and steel at high temperatures. More complicated phenomena like concrete transient thermal strain and concrete spalling are excluded in the present analysis. The validation of the proposed model is examined against experimental data of previous researches and shows good agreement.Keywords: Fire resistance, Material nonlinearity, Reinforced Concrete Slabs