KUFA JOURNAL OF ENGINEERING

Due to repeated wars against Iraq as well as the terrorist operations lead to demolition of many government and commercial buildings and thus necessitating the demolition of these buildings and throwing them as a rubble. Also any concrete structure reaches its end life, it is either repaired or demolished and transformed to waste. The waste materials were transferred to landfill and no longer used. These waste will increase with time and cause an environmental problem. So, this study was prepared to examine the ability of crushing and reusing of the demolition waste as a coarse aggregate in the production of new concrete known as a Recycled Aggregate Concrete. This study consists of two parts: experimental and theoretical parts. Both parts dealt with the effect of using recycled concrete aggregate (RCA) as a partial replacement of natural coarse aggregate in self-compacting concrete, on the structural behavior of reinforced concrete corbels. The replacement percentages were used in this study (0%, 25%, 50%, and 75%). The experimental part consists of casting and testing of ten self-compacting reinforced concrete corbels which made with either natural coarse aggregate or with a partial replacement of natural coarse aggregate by recycled concrete aggregate then the experimental results was compared with the analytical results (finite element results). The analytical part was carried out by using ANSYS program (version 18). In ANSYS program three types of elements were used in the modeling of each corbel specimen. The elements are Solid65, Link180 and Solid185. Solid 65 element was used to represent of concrete while link180 element was used to represent of steel reinforcement and finally solid185 element was used to represent the steel plates at supports and under the applied load. The ANSYS software is used to simulate the load bearing capacities of the reinforced concrete corbel and then compared with the experimental results. The results show that there is a good coincidence between the experimental and analytical results. Therefor the ANSYS software can be used to predict the shear strength of SCC corbels containing RCA with acceptable accuracy.

This paper concerns with the behavior of the connections in the composite Profiled Steel Sheet with Ferrocement (PSSF) systems. The PSSF panels is a light weight composite panel consists of a profiled steel sheet (PSS) and ferrocement panel connected together by either mechanical fasteners or by epoxy adhesive resin. Ten push-out specimens were tested. The veriables were the strength of morter and the volume friaction of wire mesh for ferrocement panels, and types of connection between the two components. The ultimate load, the load slip relationship, and modes of failure were recorded. The results showed that the specimens connected by using* bolts of 10 mm diameter can sustain load greater by 64% than those connected by using bolts of 5 mm diameter. The ultimate load was found not to be inflenced** when the strength of ferrocement is increased from 35 MPa to 45 MPa. Also the effect of volume fraction of wire mesh was observed to enhance slightly the ultimate load when the layers of wire meshs is increased from 2 to 3 layers. For the specimens made by connecting the ferrocement components to the PSS by adhesive epoxy layer, a rigid connection was obtained and sudden separation occurred between the ferrocement component and steel sheet after local buckling of PSS.

The most popular defects that infect new born babies have close connection with heart. Approximately 1% percent of new born babies suffering from defects that are caused by heart. By observing Electrocardiogram "ECG" during gestation doctors can study the fetal heart activity that collected from mother abdominal and rectify number of defects which has been diagnosed in fetal heart. Many techniques like filters, BSS and even artificial intelligence used to extract and process fetal ECG signal. In case of twins gestation the problem would be more complicated because the recorded signal is a mixture of multi signals which are mother ECG, fetuses ECG and noises where every signal comes from different source in addition fetus have the same ECG signal features as well. In this study the concentration would be on BSS techniques specifically on Stone BSS method. A comparison has been made between Stone method and two other methods "EFICA and JADE". The results proved that Stone method has better performance comparing to the other BSS techniques

This study investigates the effect of curvature ratio on the liquid-gas mixing in an air humidification process by choosing the optimum positioning of nozzles matrix fixed prior to a bent duct. The present study is considered as a simulation of the gas turbine compressor inlet air cooling by the fogging technique. The experiments were conducted using a wind tunnel with an average air velocity of (5 m/s) through a 50 cm square cross sectional duct. The study employs three curvature ratios of 0.25, 0.5 and 0.75. Also three nozzles tilt angles were tested at – 45°, 0° and 45° with respect to the axial air flow direction. The design and the configuration of the nozzles matrix is decided according to the flow structure extracted from numerical simulation using CFD analysis with RNG-k-ε turbulent model. The results indicate that a curvature ratio of 0.75 gives the best performance of the humidification system when the nozzles matrix installed as far as possible prior to the bent duct giving enough residence time for the injected droplets to evaporate. At nozzles tilt angle of 0°, the relative humidity increased about 53.63% and the corresponding reduction in air temperature was 17%. Therefore, the optimum position of the nozzles has been shown in this study is at 1.5 m prior to the curve and a tilt angle of 0° when using the largest curvature ratio of 0.75 due to the shrink in the separation zone accompany the weakening of centrifugal forces. This effect would widen the mixing area for the two streams to react and producing better cooling and humidification of the air.

Composites are produced when two or more materials are used to give combination of properties that cannot be attained otherwise. This study aims to use crab shell and charcoal reinforcements to enhance the mechanical properties of polyester composites and decrease the environmental pollution caused by the agro waste. In this study, 5 – 25 wt. % of 100 g of grounded charcoal and crab shell with an average particles size of 150 µm were used for polyester matrix composites. Flexural strength, impact resistance, hardness and elastic modulus tests were carried out on the developed samples. The microstructure of the samples revealed a uniform distribution of the reinforcements within the polymer matrix with different morphology of the biocomposites. The results showed that the greatest flexural strength value of 361.37 MPa was obtained at 25 wt. % and the highest Brinell hardness number (BHN) was 118.27 at 20 wt. %. However, the highest modulus of elasticity was 335.63 MPa at 15 wt. % reinforcement with crab shell reinforced and was 308.64 MPa with charcoal reinforcements at 20 wt. %. Furthermore, the highest impact energy was 5.49 J for crab shell and 5.31 J for charcoal reinforced polyester composite. The development of the biocomposites of these materials will decrease the environmental pollution and improve the properties of the polyester matrix composites for engineering applications.

Bentonite is a well-known type of clay and the mineralogical and physio-chemical characterization of its suspensions is essential to be investigated. In this study, the mineralogical and Physio-chemical characterization of the nano-porous structure of four industrial-grade bentonite samples namely, B1, B2, B3 and B4 were investigated to determine their mineralogical properties for a specific industrial application. Instrumental analyses of samples using XRD, XRF and BET were investigated along with laboratory tests including swelling and sediment indices, surface area and cation exchange capacity as well in order to select the appropriate sample. XRF along with slurry pH shows alkali metal ions. The results indicate B4 has calcite impurity, 50 cP viscosity reading at 600 r/min, 6 value for yield point/plastic viscosity ratio and 39.05 wt% residue of diameter greater than 75 μm. B3 is the most suitable sample for water-based fluid utilization compared to B1, B2 and B4, which satisfies the best standard requirements.