The action of high repeated trucks load associated with dramatically elevated ambient temperatures leads to the most harmful distress in asphalt pavements occurred in Iraq known as rutting. Essentially, it is produced from the accumulation of irrecoverable strains, which mainly occurred in the asphalt layers. That visually demonstrated as a longitudinal depression in the wheel paths as well as small upheavals to the sides. Poly Phosphoric Acid (PPA) has been used as a means of producing modified asphalt binders and the interest to use it has increased in recent years. The PPA provides modified asphalt binder, which is relatively cheaply produced compared to polymer-modified asphalt. In this paper, PPA was used by three-percentages 1, 2 and 3 % of the weight of asphalt binder. Two asphalt binder grades were used in this study, 40-50 and 60 -70. The evaluation process based on conducting Marshall Test, Compressive strength test and the Wheel Tracking test. The optimum asphalt content was determined for eight asphalt mixture. The results of the index of retained strength of modified asphalt were slightly increased compared with conventional mixtures. The rut depth was determined by using wheel tracking device at different temperature (45 and 55 ºC) for each asphalt mixture under 10000 cycles and the results showed that modified asphalt with PPA produced mixtures with more rutting resistance than conventional asphalt mixture. Moreover, the effect of PPA on rutting resistance for asphalt grade 60-70 was higher than asphalt grade 40-50.
In this work an approach has been developed to investigate the influence of surface roughness on thermohydrodynamic performance in aligned and misaligned journal bearings by considering an average flow model and deriving the shear flow factor for various roughness configurations, similar to the pressure flow factor. An average Reynolds equation for rough surfaces is defined in term of pressure and shear flow factors, which can be obtained by numerical flow simulation, though the use of measured or numerically generated rough surfaces. Reynolds, heat conduction and energy equations are solved simultaneously by using a suitable numerical technique (Finite Difference Method) to obtain the pressure and temperature di
... Show Moreالهدف من الدراسة هو معرفة أثر استراتيجيات التفكير البصري (VTS) على تحصيل طلاب الكلية في مهارات الاتصال باللغة الإنكليزية. ولتحقيق هدف الدراسة تم استخدام التصميم البعدي التجريبي. وتمثلت العينة بـ (70) من طلاب المرحلة الثانية بقسم اللغة الإنجليزية بكلية التربية. وقد تم اختيارهم عشوائياً وتقسيمهم إلى مجموعتين: المجموعة التجريبية والضابطة (35) طالباً في كل مجموعة. ولتحقيق هدف الدراسة تم بناء اختبار تحصيلي لمهارا
... Show MoreWriting in English language demands both mental skills and a suitable level of language proficiency. Some studies showed that writing anxiety has an impact on the acquisition of language learning. This study; however, teaches the cognitive strategies (PLAY & WRITE) as a writing strategy, so as to decrease students’ use of it when experiencing writing anxiety at the academic writing level. The sample has been (100) second-stage Department of English learners at the College of Education (Ibn –Rushd), in the University of Baghdad-Iraq. They have been randomly selected and divided into experimental and control groups; (50) students in each group. To achieve the objective of the study, SLWAI questionnaire has been distributed to
... Show MoreThe effect of three high temperatures for five exposure periods on the developments of larvae, pupae and adults of Trogoderma granarium (Everts) and their biological performance were investigated. The results revealed that the percent of mortality was increased as the temperature and the exposure period increased, e. g. exposing last instar larvae to 45°C for 6 hrs caused 100% death of this stage, while exposing adults (1-3) days old to the same temperature and exposure time resulted in that these adults did not able to survive more than 24 hrs.; in addition, the results showed that the ability of reproduction of adults was depended on the temperature, duration of exposure and the sex.
The speed of skills has become linked to modern methods of individual and group play, and each of them has begun to serve the other tactically. Through the follow-up of the researchers, they noticed that there is a significant weakness in the speed of performance and slowness in mental preparation, which plays a major role in understanding mental readiness, which is linked to the speed of making decisions during the game, as well as the weakness of the physical speed of the female players, which in turn has an impact on the skill performance of the players of the Iraqi clubs, which are the main supporter of the national team. The study aimed to identify the effect of interactive speed training on the performance of some skills among
... Show MoreOver the last few decades, many instructors have been trying all kinds of teaching methods, but without benefit. Nevertheless, in the 1986, a new technique is appeared which called K-W-L technique, it is specified for reading comprehension passages because reading skill is not easy matter for students for specific purposes (ESP).therefore, the K-W-L technique is a good one for thinking and experiences. To fulfill the aims and verify the hypothesis which reads as follows" it is hypothesized that there are no significant differences between the achievements of students who are taught according to K-W-L technique and those who are taught according to the traditional method
... Show MoreThere have been many advances in the solar chimney power plant since 1930 and the first pilot work was built in Spain (Manzanares) that produced 50 KW. The solar chimney power plant is considered of a clean power generation that needs to be investigated to enhance the performance by studying the effect of changing the area of passage of air to enhance the velocity towards the chimney to maximize design velocity. In this experimental and numerical study, the reduction area of solar collector was investigated. The reduction area that mean changing the height of glass cover from the absorbing plate (h1=3.8cm, h2=2.6cm and h3=1.28cm). The numerical study was performed using ANSYS Fluent software package (version 14.0) to solve go
... Show MoreBackground: The rhizome of ginger is used in cooking and for medicinal purposes such as anti-bacterial, anti-fungal, anti-inflammatory and antioxidant. The aims of the study were to test the effect of ethanolic extract of ginger on growth, adherence and acidogenicity of mutans streptococci in comparison to chlorhexidine gluconate 0.2% and de-ionized water. Materials and methods: From saliva often volunteers (dental students 20-22 years); mutans streptococci was isolated, purified and diagnosed according to morphological characteristic and biochemical tests. Ginger was powdered and extracted, different concentrations of ginger extract were prepared. Chlorhexidine gluconate 0.2% used as a control positive; while de-ionized water was used as a
... Show MoreMalaysia will be an ageing population by 2030 as the number of those aged 60 years and above has increased drastically from 6.2 percent in 2000 and is expected to reach 13.6 percent by 2030. There are many challenges that will be faced due to the ageing population, one of which is the increasing cost of pensions in the future. In view of that, it is necessary to investigate the effect of actuarial assumptions on pension liabilities under the perspective of ageing. To estimate the pension liabilities, the Projected Unit Credit method is used in the study and commutation functions are employed in the process. Demographic risk and salary risk have been identified as major risks in analyzing pension liabilities in this study. The sensitivity
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