KUFA JOURNAL OF ENGINEERING

In this research, low carbon steel (AISI 1006) and aluminum (AA6061) were joined by resistance spot welding. Different types of coating for the base metals were used to examine their influence on the properties of the welded joint. A tensile shear test for the welded joints was performed to determine the best welding conditions. low welding current produced an interfacial failure mode, and the failure mode changed from interfacial to partial pullout and full pullout failure modes with increasing welding current. For the as-welded joints, the best welding condition was 6 kA, 0.6 s, and the joint recorded a shear force of 2.7 kN. The shear force increased to 4.24 kN for the tin-coated steel / zinc-coated aluminum joint. The microstructure examination showed the welding made through a brazing mechanism. However, the existence of the Fe-Al intermetallic compound (IMC) caused a cracking at the joint interface. The microhardness of the joint was affected by the heat of welding and varied across the joint. An increase in the microhardness of aluminum in the weld nugget occurred because of the IMC.

The research studied the effects of adding industrial Iraqi bentonite clay on the mechanical and physical properties of the Iraqi Rutbah sand with a wide range moisture weight ratio ranging from 1.8 - 8.5%. Properties included green shear and compression resistance; permeability, hardness and moisture content. Samples of green sand blocks (standard sample 50 mm x 50 mm) adhered to Iraqi bentonite clay were subjected to test’s properties using crash index and universal strength machines.

The results showed that the ability to improve the local sand in the Iraqi Rutbah for the purpose of renewal in the preparation of molds. The results also showed that adding industrial Iraqi bentonite improved the compressive strength of the green sand mold by about 116.2%, and the shear strength by about 37.8%. It also increased the green transmittance by 12.9% and the hardness by about 9.4%.

Cold mix asphalt produced using conventional emulsion and limestone filler has three main disadvantages, namely low early strength due to high amount of water within the mix, long curing time ranging from 2-24 months and high air voids content.

In this study, the effect of a novel technology for producing high-quality cold mix asphalt using modified bitumen emulsion has been investigated in terms of indirect tensile stiffness modulus. the effect of a novel technology for homogenizing a bitumen emulsion on its viscosity, particle size and particle size distribution has been investigated. Ultrasound technology has been used to reduce the viscosity and the size of the bitumen droplets. Different samples of cationic bitumen emulsion (C50B4) have been prepared with different treatment durations (0, 5, 7, 10, 12.5, 15, 30, 45 and 60) min. The results have shown a reduction in the viscosity of the bitumen emulsion at treatment times from 5-15 min. The viscosity has been decreased by 28% after 10 min treatment for the emulsion compared to the untreated sample. This reduction indicated a uniform droplet size distribution. In addition, the particle size measurements revealed that the 7 min treatment showed a significant reduction in the D50, which was 84.5%, D10, was 85.89%, and D90 was 90.28% compared to the untreated bitumen emulsion. The results reported contains a comparison between the viscosity of the emulsions, and the indirect tensile stiffness modulus of a control conventional cold mix asphalt and the new high quality cold mix asphalt with low viscosity. Interestingly, the reduction of the 28% in the viscosity of the new emulsion causes an improvement of the indirect tensile stiffness modulus to 216%, which indicates an outstanding achievement.

Thermal oxidation (TO) of a titanium (Ti) surface was experimentally carried out at diverse conditions of temperature and time. The major goal of this paper is to study the influence of the TO treatment on the bio-wettability and corrosion behavior of investigated Ti alloy in simulated body fluid (SBF). The results revealed a substantial improvement is obtained in the bio-wettability and corrosion resistance of Ti alloy samples after TO compared to an untreated sample. Also, the optimal contact angle and corrosion resistance were observed for the sample treated at 850oC for 8 h.

The Water industry faces a significant problem in reducing water turbidity. The introduction and enhancement of proactive operation and maintenance techniques to reduce turbidity can be facilitated by the capacity to predict the geographical probability and severity of turbidity in distribution systems. In this study, the Particle Sediment Model (PSM) is used to simulate turbidity in a water distribution system. This study sought to ascertain how water treatment facilities impact the turbidity of tap Water. The Al-Saray water distribution network in Kufa city /Najaf Governorate is covered by the work The impact of water turbidity on the network revealed that the source of the particles entering the network is the treatment facility. The highest turbidity values in the system were recorded at 9.67, 16.68, 13.38, 11.30, 9.82, and 5.27 NTU when the source sediment quality (effluent turbidity from WTP) met the standard specifications of (5) NTU, while the highest values were noted when the source sediment quality (26.6) NTU was at 51.35, 101.02, 77.64, 62.94, 52.46, and 20.22 NTU. Failure to carry out continuous cleaning of the network and poor water treatment from drinking water treatment plants are among the most important reasons for the rise in turbidity in drinking water.

The Nigerian housing development industry can contribute to Sustainable Development Goal 11, through innovative construction adoption, for optimizing affordable housing. This paper presents a framework developed through a mixed research methodology. Using a purposive sampling technique, 397 private developers, and members of the Real Estate Developers Association of Nigeria (REDAN) in Lagos and Abuja were selected. Technology Acceptance Model (TAM) and Innovation Diffusion Theory (IDT), were integrated to develop a conceptual framework, used to generate a questionnaire. An Adoption Support Framework (ASF), which is an inclusive diagrammatic representation of a five-stage innovation-decision process model, showing relationships between housing stakeholders -social structures and driven by the exchange of technical data through communication channels in a social system, was developed from data analyzed using nonparametric test, descriptive statistics, regression analysis and SPSS version 22. The ASF is characterized as being transferable, and having the capacity for abstraction and theoretical generalization.

In many applications, including radar, radio and television, medical, industrial, and others, frequency estimate of a periodic sinusoidal signal is a crucial step in the signal processing process. Due to its simplicity of usage in digital systems, the interpolation-based signal frequency estimation algorithm is now frequently employed. Because of its performance speed, interpolation methods in the analysis rely on the fast Fourier transform (FFT). This paper proposes an approach for single-tone frequency estimate utilizing DFT interpolation with Parzen windowing in order to increase the accuracy of frequency estimation. In addition, compared to Li and Dian algorithm, the proposed method has a lower computing complexity and more steady performance. To minimize undesirable effects brought on by spectrum leakage from the FFT procedure, suitable windows have been investigated. To investigate the viability of the suggested method, three windows Flattop, Parzen, and Bohman, were applied to the simulation signal. When compared to the other windows, the Parzen window with the proposed algorithm outperformed them with a maximum frequency estimation error of 0.00003 compared to 0.0001 and 0.0002 for the Dian and Li algorithms, respectively, when the Sample Size was 8192.