Problematic soils, especially clayey soil, are problematic for engineering projects in their natural state because of clay's swell-shrinkage phenomenon. Numerous methods and stabilizer materials have been used to enhance clay's geotechnical properties and make them appropriate for construction. One of the significant methods of stabilization of problematic soil is using waste materials like waste glass, waste stone, waste plastic, etc. Due to the waste stone's consistency reducing water content and increasing the soil's strength, it has been employed in many civil engineering studies. Waste stone is available in various forms, including waste stone powder (WSP). WSP is produced by blasting tunnels or cutting huge stone blocks. Hence, the main aim of this study is to review the influence of WSP on improving the geotechnical properties of problematic soils treated with WSP, for this purpose, the treated problematic soils with various percentages of WSP are compared with natural soils. This study evaluates physical properties (i.e., Index properties, linear shrinkage/swelling, optimum moisture content, and maximum dry density) and mechanical properties (i.e., unconfined compressive strength and California bearing ratio). Also, the effect of WSP on decreasing the thickness of pavement layers was reviewed
Hydraulic actuators are one of the most viable choices due to their high power-to-weight ratio,low cost, robustness, fast response and great power supply. The present work focuses onbuilding an elevator prototype model simulates real hydraulic elevator. This model consists ofhydraulic parts (double-acting hydraulic cylinders, pump, valves, pipeline and filter) andelectronic parts (PLC, push-bottoms, relays and encoder). It is built with three floors in about300 cm height (total with the cylinder) to elevate a 30 kg payload and controlled by a PLCcontroller of (DELTA DVP-ES32) with 16 inputs and 16 outputs. The PLC receives input signals asorders from the operator as well as sensors and encoders. The PLC is programmed with WPSOFT2.46 Ladder diagram software to basically calling the elevator cabin through three locations andenabling its arrival at the desired floor. The cabin descent is achieved by using a proportionalcontrol valve which is controlled by the PLC. The cabin door is automatically opened and closedby DC motors. It is observed that, the application of this partnership between the PLC and theproportional valve in the build model helped to achieve excellent results in terms of systemcontrol and its efficiency, response, and smoothness.
Deep beams with rectangular cross-sections are widely used in concrete structures. In the present study, reinforced concrete rectangular deep beams cast with self-compacted concrete (SCC) which contains recycled concrete as coarse aggregate (RCA) were tested under directly and indirectly loading conditions. In the experimental work, fifteen deep beams were investigated, the first parameter considered in this study was the shear span to effective depth (a/d) ratio. The other variable is the replacement ratio by which the normal coarse aggregate is replaced by RCA. The beams were cast without the use of shear reinforcement. During the tests, the response of the beams including the cracking load, the ultimate load, concrete strain, and mid-span deflection were recorded. Test results indicate that the presence of RCA caused a reduction in the values of cracking and ultimate loads. For instance, the cracking load was reduced by 9%, 23%, and 50% and the ultimate load was reduced by 2% , 23%, and 25% as RCA replacement increased by 25%, 50%, and 75% respectively for a/d ratio equals 1.0. Further, by increasing the a/d ratio, the ultimate load was decreased due to the lower contribution of arch action shear transfer in the beam with a higher (a/d) ratio.
The aim of this article is to investigate the properties for joints of welded martensitic stainless steel (MSS) by ER 309 L filler wire, using tungsten arc welding (Tig). The regions of the base and welded materials were investigated by means of SEM, EDS, OP and HV were conducted to calculate the properties of the welded specimens. The influence of heat and cryogenic treatments also investigated, The best results from microstructure side occurrence epitaxial grains growth which was observed along the interface of weld-metal region, the maximum hardness was (414 HV) in conventional heat treated samples that tempered at 200°C, precipitation of small carbides were observed that this is responsible for the improvement in the mechanical properties of the material. Hardness at the HAZ region in state of DCT in all weldments was reduced as compared to hardness of HAZ region of CHT. The microhardness was at the highest value in the fusion zone
The porous Titanium is characterized by high permeability which can assure the ingrowth of bone tissues, and consequently results in a good bonding between the metallic implant and the bone. In this work, Silicon element was added to the Commercially Pure Titanium at different weight percent of (2, 4, 6, 8 and 10) to investigate its effect on the porosity percentage, mechanical properties of the resulted samples. XRD analysis stated that at (Si) content lower than (2 wt%) the alloy is single phase (α- Ti alloy), as the Silicon content increased, in addition to (αphase), (Ti5Si3) intermetallic compound developed in the alloy. Porosity measurement results showed that the porosity percentage increases with the increase in Silicon content. Wear results stated that the wear rate increases with the increase in silicon content due to the increase in porosity percentage while the hardness results stated that there is no significant effect for Ti5Si3 intermetallic compound on improving the hardness of the samples. This is attributed to its low percent and the major effect of porosity on hardness which declined the effect of Ti5Si3 by reducing the hardness of the alloy compared with the master sample. The obtained results of the (yield strength, ultimate compressive strength and Young’s modulus) were within the values that match bone’s properties. This means these materials are suitable for biomedical application