تحليل الشبكات في أنظمة المعلومات الجغرافية ...
تمثل الشبكة مجموعة من الخطوط والنقاط التي تمثل الكائنات الجغرافية المتصلة مع بعضها البعض والتي من خلالها تتحرك الموارد (سيارات , مياه , كهرباء , غاز....الخ)
1- أنظمة تدفق موجهة
يتحرك التدفق من المصا
در إلى المصارف
الموارد لا تملك القدرة على اتخاذ قرارات المسير
(على سبيل المثال، نظام النهر)
2- أنظمة تدفق غير موجهة
النظام لا يتحكم بشكل كامل بعملية التدفق
الموارد تملك القدرة على اتخاذ قرارات المسير الخاصة بها
(على سبيل المثال، نظام السير)
The maintenance and repair of road networks became a key and very important issue,
because of the large increase in length and the limited budget available for maintenance.
This research aims to develop an optimal strategy for maintenance of road i
n order to
distribute the annually limited budget on maintenance programs of road network as a
whole according to multiple objectives.
The proposed mathematical model ensures raising the performance of the road
network in Lattakia for the multiple targets, taking into account the constraints imposed on
the maintenance process, using goal programming technique.
To validate the proposed model we have studied the central road case, and the
samples were Lattakia-Qurdaha and Lattakia-Haffa-Slinfa roads, we have got results
represented by the number of meters can be maintained for each type of maintenance for
every degree and their locations on the road network within the funds available.
A commercial software called lingo has used to solve the linear programming model
(phase 1) and Excel program has used to design the interface for data entry required and
the formation of equations model, Excel program have also used to determine the segments
which have to maintain first on the road network (phase 2).
The proposed model may apply for the different situations of the budget (open,
closed) and for policies and multiple options in order to reach results related to sensitively
model.
The Railway track is the main factor in evaluation any railway system, because it has direct
effect on speed, comfort and safety of Train.
As it costs about 35% of total construction of new railway, this research is important to study all
elements
and use available data to evaluate the studied line, and then it analyses the results to
clarify the reaction between the defects. Therefore, the paper shows the priority of maintenance
with less prices.
In this paper, the effects on the wave shape will be studied according to the track permanent
components such as rail, sleepers or ballast.
The results show there is a step change in stress on the ballast layer. It is important to prevent
the step
change in the track characteristic module over 20%. It is also useful to provide a
transition zone to allow the gradate changing in track characteristic module.
This research Paper includes a realistic vision of the possibility of Depending on
(Public-Private-Partnership) (P.P.P) as an effective element of investment in the
construction of (Toll Road).
The research included a study of the current central
road network and plans through
the aspirations of the Ministry of Transport in Syria, according to the legitimate and
economic trends and that will make the Private sector as a partner in infrastructure
projects, including road network in Syria.
The essential objective of the research is to complete what was done previously by
the Ministry of Transport through (economic feasibility study of highway projects Based
on B.O.T system in Syria) and detailed search in the legislative and legal framework,
which is expected to be issued to cover the legal side of this mega-project which will be
done according to (Public-Private-Partnership) (P.P.P), furthermore it will be the major
support to the Syrian economic wheel after the current crises and studying the profits of
the proposed project to investment which is a freeway from northern Syria to the south and
the other one from eastern Syria to the west, an indication of the results and
recommendations display.
the purpose of this research was to concentrate on this subject, where
four types of concrete mixes of the same shape were prepared (Abrams
settlement about 20 cm), but the cement content and compression strength
in each mixture were different, al
l samples were exposed to destructive acid
effect (nitric acid, sulphuric acid ) of a ratio 3% and PH ≤ 4.
The target this paper is to evaluate the lateral resistance on CWR stability
in curves under the conditions the Syrian railway net and to determine the
minimum radiaus depending upon the numerical solution of the energy
equation.
بهدف الحصول على بلاط أرصفة إسمنتي باستعمال المواد المحلية بمواصفات عالية
فقد تم تصميم عدة خلطات باستعمال المواد المحلية بنسب مختلفة بمصروف إسـمنت
ثابت و بنسبة ماء إلى الإسمنت ثابتة فتم الوصول إلى الخلطة التي تعطي أعلى مقاومة
على الضغط. و قد تم تحض
ير بلاط في المعمل باستعمال هذه الخلطة فأعطـت قيمـاً
عالية للمقاومة على الضغط و الانعطاف و بقية الصفات، و قد تمت الاختبارات بموجب
المواصفات القياسية السورية.
طريقة دقيقة لتحديد الإجهادات و التشوهات فـي مقـاطع الخرسـانة المسـلحة العاديـة أو المسـبقة
الإجهاد. الطريقة أعدت لتحديد التشوهات اللحظية و التشوهات مع الزمن الناتجة عـن تـأثير السـيلان
و التقلص و ارتخاء الأسلاك لأي مقطع عرضي مهما كان شكله متناظراً
أو غير متناظر، و ذلك عنـدما
تكون العزوم مطبقة حول محورين X و Y .البحث يتضمن مثالاً عددياً يبين كيفية تطبيـق الطريقـة
تطبيقاً مباشراً.
The research
discusses roads rehabilitation using foamed bitumen,which is a
relatively new method and hasn’t been used in Syria yet due to the
lack of the needed labrotory equipments ,and that’s why the main
aim of the research is to develop a mo
del to stimulate the labrotory
experiments needed to evaluate the performance of the rehabilitated
pavement (surface deflection – strain ). The model was developed
using the finite elements method with the help of ABAQUS
modelling software.
