Journal of Engineering

This paper focuses on understanding the effect of angle of attack (α) on wake characteristics behind single horizontal axis wind turbines (HAWT). Three rotors with different values of α (4.8˚, 9.5˚, 19˚) were designed and used in the rotor design process. Numerical simulations were conducted using Ansys Workbench 19- Fluent code with the k-ω SST turbulence model. The results showed that the best value for extracted wind energy was at α=19˚. The spread distance of the wake behind a single HAWT was inversely proportional to the α value. The highest turbulence intensity level was observed for small values of α (4.8˚ and 9.5˚), indicating the presence of meandering phenomena in these cases. In contrast, α=19˚ showed more symmetry in wake shape due to moderate turbulence intensity, indicating the lowest aerodynamic loads on rotor components. Therefore, the best distribution for turbines in a farm could be achieved using higher values of α compared to lower values.

This work is an experimental investigation for single basin-single slope solar still coupled with an evacuated tube solar collector. The work is carried out under the climatic conditions of Baghdad city (33.2456º North and East latitude, 44.3337º longitude)through certain days of the months of the year 2019 to study the impact of using evacuated tube solar collector on the daily productivity and efficiency under the outdoors climatic conditions. It was found that using the evacuated tube solar collector increase daily productivity from 2.175 kg/????2to 2.95 kg/????2for 9 hours (35.63 %) for clear days, also an enhancement about 10.97 % in daily efficiency.Keywords: Desalination, solar still, ETC-evacuated tube collector, productivity

This research investigates the effects of using magnetized water to leach salts from salt-affected sandy loam soil. A test rig was designed to apply magnetized water with variable magnetic intensities and exposure times to soil samples placed in plastic columns. The leaching water was then tested for electrical conductivity (EC), pH, and various ion concentrations (K+, Na+, Mg+2, Ca+2, Cl-, HCO3, and SO4-2). The results showed that magnetized water significantly improved the efficiency of salt removal compared to untreated water. As the magnetic intensity and exposure time increased, more salts were leached out of the soil. The maximum increase in EC was 58.6%, and in pH was 2.4%.

This paper reviews the Moving Bed Biofilm Reactor (MBBR) and Turbo 4Bio (T4B) technologies for wastewater treatment. MBBR uses plastic carriers to transport biomass and operates at low concentrations of suspended solids, while T4B is a sustainable, cost-effective solution with minimal sludge production and easy maintenance. The study compares the two technologies, highlighting MBBR's advantages in simultaneous biological phosphorous and nitrogen removal and T4B's benefits of low cost, high production performance, and reduced energy consumption. The paper concludes that both technologies are effective, but MBBR offers more advanced biological treatment capabilities, while T4B is more cost-effective and easier to maintain.

his paper presents the design of a secure software-defined radio (SDR) transceiver using the logistic map for encryption. The transceiver employs 16-QAM modulation and integrates a security subsystem using the logistic map, a simple nonlinear dynamical equation that generates a random key. This key is used with the EXCLUSIVE OR operation on the transmitted data to ensure security. At the receiver, the data is recovered using the same key, ensuring that the received data matches the transmitted data. The performance of the transceiver was evaluated by calculating the bit error rate (BER) at different signal-to-noise ratios (SNR). The results showed that the designed transmitter and receiver perform as expected, with simulated BER values being smaller than theoretical ones obtained using the BER tool. For an SNR of 7 dB, the theoretical and simulated BER values were 0.01695 and 0.00199, respectively. The design was implemented using MATLAB R2011a and System Generator ISE14.1/SIMULINK.

This paper aims to develop and verify the pushover analysis methodology for reinforced concrete frames under earthquake loading. The technique relies on a nonlinear representation of the structure using SAP2000 software. The properties of plastic hinges are defined by generating moment-curvature analysis for all frame sections (beams and columns). The verification of this technique was compared with a previous study for two-dimensional frames (4- and 7-story frames). The comparison highlighted essential points, including potential differences between default and user-defined hinge properties in modeling, the effect of plastic hinge length, and the transverse shear reinforcement on the capacity curves. The results indicate that the current methodology is more logical in representing two- and three-dimensional structures.