Journal of University of Babylon

The impact of aggressive agents, especially chlorides, on concrete structures is a significant challenge in the field of engineering. The presence of chlorides leads to corrosion and deterioration of concrete, affecting its performance. Chlorides penetrate the concrete, leading to the destruction of the protective layer around the reinforcing steel, which results in the corrosion of the steel and the formation of rust. This corrosion negatively affects the bond strength between the steel and the concrete and can also cause cracks on the concrete surface, reducing its durability. To address this challenge, a research study was conducted to explore the use of nanomaterials, specifically nano-calcined halloysite, to improve the performance and durability of concrete. The aim was to investigate the impact of incorporating halloysite in concrete on the penetration of chlorides and the subsequent corrosion of reinforcing steel rebars.
Three different concrete mixtures containing varying percentages of halloysite (1.5%, 3%, and 4.5%) were examined. The researchers evaluated the water absorption rates and migration coefficients of these mixtures. Additionally, the impressed current technique was utilized, where a 14mA current was applied for 26 days to accelerate the corrosion of steel rebars. The results of the study demonstrated the effectiveness of incorporating halloysite in concrete to enhance its properties. The mixture containing 3% and 4.5% of halloysite (CHNC) achieved the desired objectives, significantly reducing water absorption. For example, the mixture with 4.5% CHNC showed a 42.99% reduction in water absorption after 7 days. This decrease in water absorption also led to a considerable decrease in the migration coefficient of chlorides and their penetration in the concrete. Furthermore, the inclusion of 4.5% halloysite and 25% ground granulated blast furnace slag (GGBS) in the mixture further improved its performance.

The study of the structural behavior of bridges in high-speed railways, not short ago, is one of the main data references on which designers and maintenance teams rely in this field. Many studies have been conducted on this matter. Studies in recent years focused on showing the effect of some or one of the characteristics of the model to know its effect on the dynamic behavior of the structure. Most of the studies did make a comparison between different types of moving loads, or between the ballast paths and the paths free of it. This research focused on clarifying the effect of changing the cross-sectional shape of the bridge and making a comparison between the results of the dynamic analysis of two models, the first with a solid cross-section, and the second is a ribbed. The analysis was carried out using SAP2000 software. The results showed differences in the dynamic behavior parameters of the two bridge models. At MS1 the vertical acceleration and displacement values were highest in the solid cross-section with approximate values of 2.5 m/s2 and 2.06 mm respectively, while at MS2 the higher values happened in the ribbed cross-section is 1.92 m/s2 and 1.58 mm respectively. Conclusions were made about the effects of section change on dynamic behavior at different speeds.

Wind energy is currently widely regarded as one of the most favorable green clean sources of energy. Several wind turbine principles with various generator architectures have been evolved to exchange the available wind energy into electric power. The DFIG partial Variable-Speed Wind Turbine (VSWT) system is most proper for wind turbine energy because of its numerous benefits over Fixed-Speed Wind Turbines (FSWT). This paper introduces a comparative review of the different wind turbine conversion energy and a valuable summary of the recent work in the literature on different Wind Energy Conversion Systems (WECS) of a DFIG modeling, Maximum Power Point (MPP), and the latest control system for operation. On the other side, comparisons and discussions between different wind turbines have been presented in the current study to be beneficial for research studies.

The assessment of the pavement condition index (PCI) is one of the main goals of the current research. The best maintenance management procedure and riding level may be attained with the fewest resources and fastest trip times. PCI values play a significant role in determining pavement maintenance, choosing economical alternatives and increasing the development of engineers and technician’s capabilities. Using survey data, PAVER software calculates a pavement condition index that should range from (zero) which indicates a failing pavement condition to (100) which indicates a good pavement condition. The state of the pavement helps to foretell the need for maintenance and rehabilitation. Instead of using evaluation technologies, a manual geometry and categories of defects survey were utilized to identify the kind, level of seriousness and defects for sample units along the road. In this research, PAVER 5.2 Program used to determine PCI values for Road No. 80 in Hilla City which is a minor arterial urban roadway The implementation of the PAVER 5.2 Program based on the collection of field inspection data yielded a PCI average value of (63.33) and this indicates that the road in chosen research section was in fair condition.

The production of microspheres from polymer emulsions using microfluidic devices has shown great potential for drug delivery applications due to their ability to encapsulate and release drugs in a controlled manner. In this study, the effects of velocity, density, viscosity, and surface tension, as well as channel diameter, on microsphere generation were investigated using Fluent Ansys software. The software was programmed with the physical properties of the polymer emulsion such as density, viscosity and surface tension. Simulation will then be performed to predict fluid flow and microsphere production and improve the design of drug delivery applications based on changes in these parameters. The effects of capillary and Weber numbers are also studied.
The results of the study showed that the size of the microspheres can be controlled by adjusting the speed and diameter of the channel. Narrower microspheres resulted from narrower channel widths and higher flow rates, which could improve drug delivery efficiency, while smaller microspheres resulted from lower interfacial surface tension. The viscosity and density of the polymer emulsion significantly affected the size of the microspheres, it`s higher viscosities and densities producing smaller microspheres.
The loading and drug release properties of the microspheres created with the microfluidic technique were also predicted. The results showed that the microspheres can efficiently encapsulate drugs and release them in a controlled manner over a period of time. This is due to the high surface area to volume ratio of the microspheres, which allows for efficient drug diffusion. The ability to tune the manufacturing process using factors such as speed, density, viscosity, channel diameter, and surface tension offers a potential opportunity to design drug delivery systems with greater efficiency and fewer side effects.

This study is aims to improve the properties of aluminum alloy 7075 by conducting heat treatment and mechanical processing. The development experiment was carried out by subjecting the samples to the process of warm squeezing, as well as conventional heat treatment. An improvement in the tensile and machining properties of the samples was noticed after the warm squeezing process. The warm squeezing caused the elongation percentage, yield strength, and the tensile strength of the heat-treated sample to increase by 11%, 40%, and 19% respectively. In addition, a significant increase of 62%, 94% and 191% in the plastic behavior of the squeezed sample was observed during the tensile test at temperatures 200, 250 and 300°C respectively. The mechanical warm squeezing showed an improvement in the machining characteristics of the alloy, as it reduced the surface roughness by 66%, but it increased the cutting force by 34%.