The Ground Penetrating Radar (GPR) is frequently used in pavement engineering
for road pavement inspection. The main objective of this work is to validate
nondestructive, quick and powerful measurements using GPR for assessment of subgrade
and asphalt /concrete conditions. In the present study, two different antennas
(250, 500 MHz) were used. The case studies are presented was carried in University
of Baghdad over about 100m of paved road. After data acquisition and radar grams
collection, they have been processed using RadExplorer V1.4 software
implementing different filters with the most effective ones (time zero adjustment and
DC removal) in addition to other interpretation tool parameters.
The interpretation results showed that with 250 MHz antenna, the buried plastic pipe
and the flexible pavement layer were identified. The later appeared as one layer
without identifying the rigid pavement layer. With 500 MHz antenna, the plastic
pipe, rigid pavement, appeared clearly. Moreover, the short type of maximum time
window using antenna 500 MHz appeared to be the most suitable for detecting some
radar anomalies (plastic pipe, and pavement thickness) which were clearly defined.
While, the suitable radar wave velocity was 100 m/ns for estimation of the flexible
and rigid pavement layer thicknesses respectively. No change is obtained with
changing point interval. . Finally, this diagnostic tool of GPR for pavement defects
and damages investigations seems very promising, cost effective and efficient in its
implementation.
The aim of this research is to analyze the content of the science textbook for 7th grade Iraqi schools in the light of the educational concepts of sustainable development, the science textbook (1st edition), for the academic year 2017-2018. To this end, the researchers prepared list of issues in the light of the educational concepts of sustainable development, consisted of (13) issues, branched to (51) subissues, presented to a group of arbitrators and specialists in science curriculum and methods of teaching. The researchers analyzed the content of the 7th grade science textbook, in the light of the list that is built, the idea has been adopted as a unit of analysis. One of the most important findings is attention to neglected sub-issues o
... Show MoreMineral fillers are a fundamental component of asphalt mastic and play a critical role in governing the mechanical performance and durability of flexible pavements. Variations in filler type and dosage can substantially alter mastic stiffness, deformation resistance, fatigue behavior, and adhesion. The objective of this study is to systematically evaluate the influence of mineral filler type and filler-to-asphalt (F/A) ratio on the rheological, fatigue, and adhesive performance of asphalt mastics. Three commonly used fillers; limestone dust, Portland cement, and hydrated lime were investigated at four F/A ratios (0.6, 0.8, 1.0, and 1.2). A comprehensive experimental program was conducted, including conventional binder characterization, Mult
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Background: The use of electronic apex locators for working length determination eliminates many of the problems associated with the radiographic measurements (interference of anatomical structures, errors in projection such as elongation or shortening, and lack of three-dimensional representation). Its most important advantage over radiography is that it measures the length of the root canal to the apical constriction, not to the radiographic apex. The aim of this study was to assess the accuracy of a new fifth generation apex locator (Joypex 5) in recording the apical constriction and comparing it with a third generation apex locator (Root ZX) in vitro. Materials and method: Twenty four single-rooted sound human premolars, extracted for t
... Show MoreBackground: The desire for an attractive appearing fixed orthodontic appliance fueled the use of ceramic brackets and clear accessories. Elastics are one of the most versatile materials available to orthodontists so studying their effect on the esthetic appearance is important. This an in vivo study, conducted to evaluate the effect of exposing stretched clear elastomeric ligatures to the oral environment from four different companies (OrthoTechnology, Morelli, Ortho Organizer, and Ormco). Materials and Methods: A total of 240 elastomeric modules were examined, 60 modules from each brand. Each of the 60 patients enrolled in the study, received 4 elastomeric modules on the 4 lower incisors, one from each brand. The specimens were placed on t
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The assessment of the environmental impact of the cement industry using the Leopold Matrix is to determine the negative and positive impacts on the environment resulting from this industry, and what are the long-term and short-term effects, direct and indirect, and the amount of these effects and potential risks, and that this evaluation process is done through a number of methods, including Matrix method, including (Leopold).
The importance of the research because the cement occupies is of great importance in the world, especially in our country, Iraq, in the sector of construction and modernity, and the toxic emissions and solid waste produced by the production of this material. <
... Show MoreFailure in asphalt mixture and distress in pavement are major issues to roads infrastructure. Selecting an appropriate chemical composition of asphalt cement is a key component in avoiding these issues. This work aimed to investigate the effect of the chemical composition of different polar fractions on the rheological and physical properties of asphalt cement. Four types of asphalt cement with penetration grades of 20/30, 40/50, 60/70 and 85/100 were divided into four fractions. Complex shear modules, rutting resistance and rotational viscosity of the asphalt cement were determined by using a Dynamic Shear Rheometer and a Rotation Viscometer, respectively. The results show that an increase in the asphaltene content and Gastel index resulte
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Abstract
This study aimed to identify the business risks using the approach of the client strategy analysis in order to improve the efficiency and effectiveness of the audit process. A study of business risks and their impact on the efficiency and effectiveness of the audit process has been performed to establish a cognitive framework of the main objective of this study, in which the descriptive analytical method has been adopted. A survey questionnaire has been developed and distributed to the targeted group of audit firms which have profession license from the Auditors Association in the Gaza Strip (63 offices). A hundred questionnaires have been distributed to the study sample of which, a total of 84 where answered and
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