Employing New Innovative Material for Airfield Pavement

The maximum surface deflection, the maximum horizontal tensile strain (εt) at the bottom of asphalt concrete (AC) layer and the maximum compressive strain (εc) at the top of subgrade are the most commonly used criteria for flexible pavement design. They were used in this study as the basis of measuring the flexible pavement response. The main objective of this paper was to investigate the effect of horizontal force on the behavior of airfield pavement and new reinforced concrete slab during aircraft ground operation. In addition, the effects of various aircraft’s wheel load configurations on the predicted airfield pavement life were discussed. To achieve these objectives, theoretical analysis, using the finite element (FE) programs SAP2000 and (ADINA) were preformed. The research plan includes studying different sections of airfield pavements, where different AC layer thickness and different AC module were used. Based on the work of this study, modulus of elasticity, E1 had a significant effect on the flexible pavement response and the predicted pavement life. There are three forces acting on the pavement through the tire: 1) longitudinal force (LGF), which is the tractive or breaking force, 2) lateral force (LTF) and 3) vertical wheel load (VL). At critical airfield pavement sections, the pavement life decrease significantly due to existence of horizontal forces at these sections. Also, the new reinforced concrete slab gives better results

Influence of Bentonite Content on the Compressibility Parameters of Processed Sand-Bentonite Mixtures

Bentonite has employed by industry to exercise various structural applications due to its unique properties especially when the material is transferred to a liquid state under water. Swelling property of bentonite to produce various water suspensions, which depends upon the relative constituents of clay and water. These mixtures are employed as bonding and plasticizing agents. Bentonite provides a large surface areas per unit weight of clay, due to its large surface area in stabilizing the medium to carry other chemicals. Bentonite react chemically with many organic material to form compounds which are used as a gelling agents in a variety of organic liquids.One-dimensional consolidation tests are performed on four sand-bentonite mixtures containing 10, 20, 30 and 40 % by dry weight bentonite to study the 1-D compressibility behavior of compacted sand-bentonite mixtures. These speciments are mixed at wet of optimum water content. To overcome the problem of the high tendency of bentonite to swell, two techniques are used. The first one is following the consolidation-swel test procedure by Nelson and Millerand the other one is mixing the soil at water content equivalent to liquid limit. The water contents for these tests are chosen in an attempt to achieve the same initial void ratio of 0.71 for all bentonite contents. Finally, final conclusion is mentioned for the effect of bentonit content on the compressibility parameters of sand-bentonite mixtures. This research arrived to that the initial water content has no effect on the mixture,which contains10 percent bentonite, whereas a significant effect is noticed for 20 and 30 % bentonite mixtures. It was found that for mixtures containing 20 and 30 % bentonite, the compressibility parameters, Cc, Cs, av, and mv for the specimens mixed at liquid limit are higher than those for specimens mixed wet of wopt

Design and Construction of the ferrocement Water Tanks

Ferrocement is proposed to construct of water tanks with high strength, crack resistance, high ductility, impact resistance and energy absorption suitable for rise buildings. This paper presents the results of an analytical study of proposed ferrocement water tanks. The cement sand matrix of the ferrocement composite was designed to achieve high compressive, tensile and flexural strengths for the produced ferrocement tanks. This was achieved by employing silica fume as replacement percentage of the cement content. The results of an experimental investigation of the effect of silica fume on the strength of the matix is also included. The complete analysis and design of twelve ferrocement water tanks with different capacities and their estimated costs are also included. The optimum limit of partial replacement of cement with silica fume was found to be 15%, which exhibited the highest increase in strength. The structural analysis and design of ferrocement water tanks were determined. The developed ferrocement tanks are four times cheaper compared with the other constructed tanks. The developed ferrocement tanks could be used successfully for the developed and developing countries alike

Experimental Analysis of Centerally Openned Two-Way Slabs Strengthened with Carbon Fiber Laminates

This study is an experimental and analysis investigation of the behavior of two-way simply supported RC flat slabs with centered circular, rectangular, and square openings. Four models were tested to failure, consisting of a referencemodelwithoutopening,andthree modelswithanopening and Carbon Fiber Reinforced Polymer (CFRP) laminatesapplied tothetensionfaceof the models.Theresultsrevealed that externallybondedCFRPlaminates significantly increased boththeoverall stiffness and flexural capacityofthemodels provided withanopening. CFRP anchoring method can further increase the performance of the strengthening scheme used. Experimental load-deflection curves and failure modes are discussed

The role of MR diffusion in differentiation of malignant and benign hepatic focal lesions

AbstractAimTo determine if focal liver masses could be differentiated as benign or malignant by DWI and ADC maps.Methods and materialsSixty focal liver lesions were scanned using 1.5T MRI. DWI was performed with b 0, b 500 and b 1000 gradients with ADC measurements. Comparison of mean ADC values between each benign and malignant lesion was done. Reference standard of diagnosis was obtained by correlating DWI with histopathologic findings and imaging follow-up. The accuracies of DWI and ADC values were assessed with the Student’s t test, and cut-off values were determined with receiver operating characteristic curve analysis.ResultsWhen ADC value of 1.0×10−3mm2/s was used as a threshold value for differentiation of malignant tumors from benign lesions, sensitivity was 90.3%, specificity 78.57% and accuracy 86.7%. The best result was obtained with the use of ADC cut off value (at b 500) of 1.5×10−3mm2/s and ADC cut off value (at b 1000) of 1.0×10−3mm2/s, with 90.3% sensitivity, 92.86% specificity, 91.1% accuracy, 96.6% positive predictive value and 81.3% negative predictive value.ConclusionDWI and ADC map is a useful tool in differential diagnosis of malignant from benign liver lesions

Software agents

book revie

ICS 343: Fundamentals of Computer Networks (3-3-4)

Junior Level Course Syllabus on Computer Network

A Heuristic Approach for Firewall Policy Optimization

A primary goal of this paper is to develop a heuristic approach based on genetic algorithms to enhance the firewall performance. Typical firewall policies may have thousands of rules and determining an optimal rule order that minimizes the average number of rule comparisons while maintaining the policy integrity is proven to be NP-hard. This problem is formulated as a binary integer program for which an optimal solution is obtained using the branch-and-bound technique. Then an alternative solution approach is devised based on genetic algorithms. Several experiments are conducted to evaluate the effectiveness of the proposed approach as compared to other rule-ordering techniques. Empirical results show the potential and flexibility of the proposed approach

A review of network security

book revie

A general look at building applications for mobile devices

book revie