Aluminum alloy (AA-6061) chips were recycled using hot extrusion followed by equal channel angular pressing (ECAP) process at room temperature. AA-6061chips were cold compacted into billets, then extruded into rods under extrusion ratio of 5.2 at different extrusion temperatures (ET). Finally, the rods were processed through ECAP die with inner angle Φ of 90°, and outer arc angle Ψ of 32.8°, which impose strain ɛ of 1 per each pass up to different number of passes. The effects of the ECAP number of passes and extrusion temperature on the microstructure and mechanical properties were fully investigated. Grain refinement were noted after the ECAP process. Moreover, the ECAPed samples revealed higher mechanical properties than those of the extruded samples. The extrusion temperature (ET) and the number of the ECAP passes have an obvious effect on both the microstructure and mechanical properties of the solid state recycled chips samples.

This search represented tests of reinforced concrete beams were tested in laboratory for shear strength. Beams consisted of six of reinforced concrete beams without stirrups, one with Rsec and five with T-sec, with variable flange width to web width ratio. All beams were loaded under two identical point load till failure. During loading of beams deflection was measured, steel strain at mid span, steel strain at mid shear span, stains at inclined strut, and strain at upper flange. Code equations usually does not account for the contribution of the flange of the T-sec while experimental research indicated enhanced shear strength for beams with flange. Test results of this research indicated an enhance of shear strength ranging from 10-30% due to the contribution of the flange.

This research paper is concerned with studying and evaluating the geoengineering characteristics and potential risks of the area under study with a view to safe urban expansion using GIS techniques. Different geotechnical laboratory tests such Atterberg limits, free swelling test, swell potential and pressure tests, chemical analysis, unconfined compressive strength (UCS) and rock quality designation (RQD) were performed on 28 boreholes (95 samples). Furthermore, X-ray diffraction was used to examine clay minerals. The results indicate that the UCS values range from 47 to 72.2 kg/cm2 and RQD from 21 to 45%. The free swell ratio ranges from 110 to 120%, and the plasticity index from 34 to 37%. In addition, GIS techniques have been utilized to produce the distribution layers of different geotechnical characteristics, then integrated to produce a geospatial urban model for delineating and defining safe and dangerous urban zones. This model is classified into four classes: low, moderate, high and very high hazard. Low and moderate hazards were detected in the major portion of the survey area. These portions are suitable for foundations at shallow depths. However, high to very high hazards were detected in the southeast portion of the study area. The reason for these areas is caused by the existence of heavily fractured limestone and highly swelling clay layers. This model would aid in the creation and discovery of the best areas of shallow base in the region under consideration.

This paper presents an optimization model for improving stability levels of thinwalled composite beams under axial compressive loading. Optimum designs are obtained by maximizing the critical buckling load while maintaining the total structural mass at a prescribed value equals to that of a baseline design. The dual problem of minimizing the total structural mass under preserved buckling load is also addressed. The developed optimization models deal with slender beam-columns that are axially graded in both material and wall thickness. The main structure is constructed from uniform segments that are fabricated from a composite with different volume fractions of the constituent materials, making the physical and mechanical properties change piecewisly in the axial direction. Design variables include the volume fraction of the constituent materials, the wall thickness as well as the length of each segment composing the beam. The buckling load analysis is performed via finite element method, using a beam element with two degrees of freedom at each node. The resulting optimization problem has been formulated as a nonlinear mathematical programming problem solved by invoking the Matlab optimization toolbox routines, which implement the method of sequential quadratic programming interacting with the associated eigenvalue problem routine. The proposed mathematical models have shown that the use of material grading concept can be promising in raising stability boundaries without mass penalty and producing economical designs having enhanced stability as compared with their corresponding baseline designs. Finally, the given approach can be beneficial to guide structural engineers for choosing the significant design variables in proper and efficient way without violating economic feasibility requirements.