Effect of Changing Theoretical Maximum Specific Gravity on Asphalt Mixture Design

The value of theoretical maximum specific gravity of bituminous paving mixture (Gmm) plays a significant role in the performance of paving mixes. The Impact of (Gmm) can be noticed on properties of bleeding, rutting, raveling, and fatigue. Calculation of Gmm is fundamental to the design process of asphalt concrete mixes. It can be measured either directly by using the standard Rice test method (AASHTO T209, ASTM D2041), or can be estimated indirectly based on the effective specific gravity of aggregate mixtures, and specific gravity of asphalt. In the latter case exact determination of percentage air voids, and optimum asphalt content values is pivotal in estimating the true value of Gmm. This paper aims to study the Impact of changing theoretical maximum specific gravity for asphalt mixture on the characteristic of asphalt mixes. To achieve this objective an extensive experimental program was designed. Two types of aggregates (limestone and basalt) as well as four mix gradations were used to conduct the study. Based on the study results, it has been found that the measured air voids content using Gmm value measured by rice test (AVm) is lower than the estimated air voids content (AVe) in about 20% and 9% for limestone and basalt, respectively. Consequently, the optimum asphalt content values based on the laboratory-measured Gmm (ACm) are lower than those which were determined by using the estimated Gmm (ACe) by about 7% and 2% for limestone and basalt, respectively. Therefore, it is recommended to use the rice test in determining the theoretical maximum specific gravity of asphalt mixture in Egyptian code

A quality assurance technique for the static multileaf collimator mode based on intrinsic base lines

AbstractThe inspection of the static leaf positions of Multileaf Collimator (MLC) devices is essential for safe radiotherapy deliveries in both static and dynamic modes. The purpose of this study was to develop a robust, accurate and generic algorithm to measure the individual static MLC leaf positions. This was performed by extracting leaf tip locations from the radiographic film image and measuring their relative distance from a reference line on the film. The reference line was created with a selected set of MLC leaf sides. The film scaling was created and verified using the physical leaf width. The average measured distance corresponds to a leaf width of 10 mm was 9.95 ± 0.09 mm. The estimated reproducibility of the leaf tips location was ±0.26 mm. The code accuracy was checked by intentionally positioning set of leaves with small errors (1 mm), and the detected deviations from the expected positions ranged from −0.25 mm and +0.32 mm. The algorithm includes two self testing functions in order to detect failures of leaf positioning due to poor film quality and to avoid the potential systematic errors attributable to the improper collimator setting. The code is promising to be more efficient with Gafchromic and Electronic Portal Imaging Device (EPID)

The Roots of Turmoil in the Egyptian Organization for Human Rights: Dynamics of Civil Institution-Building in Egypt

First presented at the 1994 Cairo Papers Annual Symposiumhttps://fount.aucegypt.edu/faculty_book_chapters/1935/thumbnail.jp

Edges Detection Based On Renyi Entropy with Split/Merge

Most of the classical methods for edge detection are based on the first and second order derivatives of gray levels of the pixels of the original image. These processes give rise to the exponential increment of computational time, especially with large size of images, and therefore requires more time for processing. This paper shows the new algorithm based on both the Rényi entropy and the Shannon entropy together for edge detection using split and merge technique. The objective is to find the best edge representation and decrease the computation time. A set of experiments in the domain of edge detection are presented. The system yields edge detection performance comparable to the classic methods, such as Canny, LOG, and Sobel.  The experimental results show that the effect of this method is better to LOG, and Sobel methods. In addition, it is better to other three methods in CPU time. Another benefit comes from easy implementation of this method. Keywords: Rényi Entropy, Information content, Edge detection, Thresholdin

COMPUTER ANALYSIS OF CURRENT SOURCE INVERTER INDUCTION MOTOR DRIVE SYSTEMS

The known concept of supplying an induction motor from a static current source converter results in ac drive performance with several important advantages over the more familiar voltage fed inverter. All ac drive using such a current source inverter is shown in Fig. 1. Basically, it consists o