An-Najah Blogs :: An-Najah Blogs :: en-us Sun, 03 Jul 2022 14:10:23 IDT Sun, 03 Jul 2022 14:10:23 IDT Management of Olive-Mills Wastewater in Palestine ArticlesDifferent treatment technologiees are reported to have been applied for treating olive-mills wastewater OMW Among these are the anaerobic combined with aerobic forced evaporation chemical and biological treatment methods The reuse of the solid residueof olive-mills is reported among others as burning material or as filtering media This paper evaluates the treatment options of the OMW generated in Palestine It eloborates on the different treatment and management alternatives and examines their effectiveness A sample of 20 mills has been surveyed in the Nablus-Tulkarm region and their wastewater quantities and characteristics are presented Centralized treatment and disposal plants for OMW are recommended as a practical option for Palestine Oil extraction process modifications in combination with forced evaporation are recommended as the most appropriate management and treatment optionThe Effect of Beams Stiffnesses on the Load Distribution in a Single Simply Supported Two-Way Ribbed Slab ArticlesSAP2000 program is used to analyze single simply supported two-way ribbed slab models from 5 x 5m to 5 x 25m supported on beams of different stiffnesses This paper concentrates on the distribution of the loads to the perimeter beams and to the ribs in both directions The discussion of results showed that the distribution of moments along the parallel ribs in the short and long direction depends in addition to the aspect ratio on the relative stiffnesses of the slab ribs and the beams on which these ribs are supported Also the distribution of loads to the perimeter beams depends on the relative stiffness between the beams and the slab ribs in addition to the panel aspect ratio Tables and curves that relate the load distribution factors with the aspect ratio and the relative stiffnesses of the supporting beams are presented as an outcome of this studyمراسلة قصيرة: استخدام وحدات مسبقة الصب في إنشاء القباب: قبة مسجد صلاح الدين الأيوبي في طولكرم – فلسطين Articlesإن هذه الورقة تصف طريقة حديثة في بناء القباب تم استخدامها عملياً في إنشاء قبة مسجد صلاح الدين الأيوبي في مدينة طولكرم، إحدى مدن الساحل الفلسطيني وقد أثبتت الطريقة فاعليتها لقد تم استيحاء هذه الفكرة من طرق إنشاء القباب التقليدية التي كانت متوارثة عبر تاريخ العمارة الإسلامية حيث أنه ومع تطور الخرسانة شاع انتشار طريقة استخدام الخرسانة المسلحة في إنشاء القباب بعد أن يتم تشكيل طوبار من الخشب بشكل القبة المطلوب، إلا أن هذه الطريقة لها عدة سلبيات مما أدى إلى التفكير باستخدام طريقة جديدة تتمثل في استخدام وحدات مسبقة الصب يتم تصنيعها من الخرسانة ثم يتم بناؤها لتشكيل القبة المطلوبة دون الحاجة إلى طوبار الخشب وفي هذا البحث وصفٌ لهذه الطريقة الجديدة بعد استعراض الطرق المختلفة المستخدمة في إنشاء القباب ومقارنة لهذه الطريقة مع باقي الطرق من حيث الميزات و السلبيات مجلة جامعة النجاح للأبحاث - العلوم الطبيعية أ ISSN: 1727-2114 المجلد 16 ، العدد 1 ، 2002 ، الصفحات: 063-080Proceeding of the second Palestinian engineering ArticlesTHE EFFECT OF ADDING ZEBAR AS AN ADMIXTURE ON THE DURABILITY AND PERMEABILITY OF CONCRETE Narmin Radi AI-Barq An-Najah Community College Dr Riyad A Karim An-Najah National University Department of Civil Engineering DrOsama Abaza An-Najah National University Department of Civil Engineering Abstarct The effect of adding Zebar as partial replacement of mixing water on the properties of concrete is investigated In particular this research is done to study the effect of adding Zebar on durability and permeability The effect on durability is studied by performing abrasion test using Rotating Cutter Head Machine The effect on permeability is investigated by measuring the air content of freshly mixed concrete using the pressure method Furthermore absorption test has been done for the specimens at age of 28 days Our results show that the compressive strength decreased when the Zebar percentage was up to 10 of mixing water but beyond that the compressive strength increased by increasing the Zebar percentage Furthermore at a Zebar percentage of 30-35 the compressive strength increased up to 24 of the strength of concrete without using Zebar Regarding permeability the results show that the air content for all mixes increased up to 5 by adding Zebar this implies that Zebar can be used as air entrained agent especially in frost conditions The 1st-MINIA INTERNATIONAL CONFERENCE FOR ADVANCED TRENDS IN ENGINEERING ArticlesFinite Element Analysis of Reinforced Concrete Cross-vault Shells By Shuhrat Hani Tawfq Arafat Dr Riyad A Karim Civil Engineering Department AN-Najah National university 1998 ABSTRACT Thousands of years ago man had discovered the idea of using vault systems built in stone to cover large areas The Romans used the vault system widely especially in the construction of roofs of thermae One vault system is that system which is constructed by two intersecting cylindrical vaults known as cross-vault system Muslims also used this system especially to cover large areas of the holly places mosques and it became a tradition in the construction of mosques for hundreds of years In modern architecture shell structures occupy a place of increasing importance because of their strength economy and architectural form At the end of previous century and the beginning of this century some scholars started to study the distribution of stresses in plates and shells Their studies showed that in most cases the shells are under compression The vast use of concrete nowadays which has good strength under compression and weak strength under tension encourages the use of concrete as a new material for the old structural conception of shells Prior to the 1970s engineers used the membrane theory to analyze cross-vault shells Based on a statically determinate analysis neglecting bending stresses this theory gives uniform in- plane shearing stress resultants on all element sections parallel to the edges At 45 from the boundaries these forces resolve into the principal compressive stresses resultants in the convex parabolas implying that the hyperbolic shell carries the vertical load through arch action In this paper the Finite Element Linear Analysis is used to study the stress distribution in cross vault shell model and finding the best geometry of this type of structures that leads to the minimum tensile stresses at the surface of the shell and puts all elements in that surface under compression The Finite element analysis is made using an available and widely used software program called STAAD III and a triangular three noded element is assumed in the analysis Finite element analysis have shown that the shape of the cross-vault shell is very proper in getting compressive stresses only and membrane theory assumption for the behavior of cross vault shells is incorrect at certain sections and the junction between two shell surface leads to a large stress concentration So this paper proposes a des Based on these observations in which small crown beams at the shell junctions introduced and material is added near the supports to reduce high stress concentryti that results at this corner and free edges for the shell