Effect of the curved vane on the hydraulic response of the bridge pier

Qasim, Rafi M.,Jabbar, Tahseen A.,Faisa, Safaa H. Techno-Press 2022 Ocean systems engineering Vol.12 No.3

Hydrodynamic field alteration around a cylindrical pier using a curved vane is numerically investigated. The curved vane with various angles ranged from 10 to 220 degree is placed at the upstream of the cylindrical pier. Laminar flow is adopted in order to perform the steady-state analysis. It is found that the flow separation leads to the formation of four bubbles depending on the value of the curved vane angle. Two bubbles are located in the region between the rear of the curved vane and the leading surface of the cylindrical pier, while the remaining two bubbles are located at the wake zone behind the cylindrical pier. Numerical analysis is performed to reveal the hydrodynamic field and influence of curved vane on the formation and evolution of the bubbles. It is found that the center and size of the bubble depend mainly on the value of the curved vane angle. It is observed that the flow velocity vector shows clearly the alteration in the flow velocity direction especially at the leading surface and rear surface of the curved vane owing to the occurrence of flow separation and flow dissipation along the circumference of the vane.

Experimental investigation on the effect of cementitious materials on fresh and mechanical properties of self-consolidating concrete

Shariati, Mahdi,Rafie, Shervin,Zandi, Yousef,Fooladvand, Rouhollah,Gharehaghaj, Behnam,Mehrabi, Peyman,Shariat, Ali,Trung, Nguyen Thoi,Salih, Musab N.A.,Poi-Ngian, Shek Techno-Press 2019 Advances in concrete construction Vol.8 No.3

Although applying self-consolidating concrete (SCC) in many modern structures is an inevitable fact, the high consumption of cement in its mixing designs has led to increased production costs and adverse environmental effects. In order to find economically viable sources with environmentally friendly features, natural pozzolan pumice and blast furnace slag in 10-50% of replacement binary designs have been investigated for experiments on the properties of fresh concrete, mechanical properties, and durability. As a natural pozzolan, pumice does not require advanced equipment to prepare for consumption and only needs to be powdered. Pumice has been the main focus of this research because of simple preparation. Also to validate the results, in addition to the control specimens of each design, fly ash as a known powder has been evaluated. Moreover, ternary mixes of pumice and silica fume were investigated to enhance the obtained results of binary mixes. It was concluded that pumice and slag powders indicated favorable performance in the high percentage of replacement.

Influence of Iron Doping on Structural, Optical and Magnetic Properties of TiO2 Nanoparticles

R. Zahid,M. Manzoor,A. Rafi q,M. Ikram,M. Nafees,A. R. Butt,S. G. Hussain,S. Ali 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.5

In this study, various concentrations of Fe doped TiO2nanoparticles have been successfully synthesized using the sol–gelmethod. A variety of characterization techniques as ultra-violet visible (UV–Vis) spectroscopy, X-ray diffractometer (XRD),vibrating sample magnetometry (VSM) and field emission scanning electron microscopy (FESEM) were employed to analyzethe prepared nanopowders. XRD measurement confirmed the substitution of Fe ion without disturbing the tetragonal crystalsystem of TiO2. The crystallite size was found to decrease and lattice strain increases upon doping estimated by WilliamsonHall plot. Furthermore, the average grain size calculated by FESEM found was between 10 and 30 nm for pure and dopedTiO2. UV–Vis spectroscopy showed an increase in absorption accompanied red shift and increase in band gap energies from3.36 to 3.62 eV with the addition of Fe. The FTIR spectroscopy was employed to confirm the presence of functional groupsin the fabricated nanopowders. Upon mixing the saturation magnetization (Ms) varying from (2.12 to 1.51)10−2 emu/g wasobserved.

Comparison of Numerical Simulation and Experiment of Designed Vortex Type Micro hydro Water Turbine

Ema Amalia,Hendarko,Muhammad N Hamzah,Faridl A Maulana,Farhan H Budisatrio,Muhammad Rafie,Mochammad A Moelyadi 한국유체기계학회 2022 International journal of fluid machinery and syste Vol.15 No.3

Vortex type's micro hydro water turbine is a new technology for harvesting energy from water which the performance is still providing more c hallenge . After h aving designed the vortex type water turbine in previous work, a laboratory scale experimental apparatus is built to prove the design and to val idate numerical simulations of the turbine The important design parameters such as torque, powe r, and efficiency are considered. It is found that the CFD results gives higher t orque , power, and efficiency compared to experiments results with a similar tren d This is due to no feature in the used CFD software in evaluating mechanical friction that ha ppened in experim ents device , for more specific in torque meter used Head of CFD for discharge of 2.7 L/s and 2.8 L/s are 0.06 m and 0.06 m while from experimen t is 0.07 m and 0.072 respectively. A NSYS has been used for CFD simulation.

Novel Sn-doped WO3 photocatalyst to degrade the organic pollutants prepared by green synthesis approach

N. R. Khalid,Samavia Ilyas,Faisal Ali,Tahir Iqbal,M. Rafi que,Muhammad Imran,Mohammad A. Assiri 대한금속·재료학회 2024 ELECTRONIC MATERIALS LETTERS Vol.20 No.1

The organic pollutants are polluting the drinking water so, it is a fi eld of great interest to clean this water by using somesophisticated materials. For this purpose, the nanostructured materials are playing vital role to attain sustainable and puredrinking water by degrading organic pollutants. The synthesis of such photocatalytic material without using harmful chemicals,is one of the important existing challenges. Thus, to tackle this challenge, we have prepared green synthesized Sn-dopedWO 3 nanomaterials by varying the content of Sn from 2 to 6 wt% and assisting from moringa oleifera seeds’ extract. Thecrystal structure, morphology, optical and photoluminescence properties of as prepared samples were investigated throughx-ray diff raction (XRD), scanning electron microscopy (SEM), ultraviolet visible spectroscopy (UV-vis) and photoluminescencespectroscopy (PL) techniques. Among of as prepared samples, the 4Sn-WO 3 (4 wt% Sn doped WO 3 ) sample hasexhibited the reduced optical band gap value i.e. 2.80 eV than 3.02 eV for pure WO 3 sample. This optimized sample has alsoshown the lowest e-h recombination rate. To test the photocatalytic performance, the methylene blue was used as a modeldye. Out of all samples, 4Sn-WO 3 sample has shown 95% degradation activity against this water pollutant. These fi ndingsspecify that the as mentioned novel photocatalytic nanomaterial will provide a signifi cant advancement in the environmentalfi eld to degrade the organic pollutants.

Fire performance curves for unprotected HSS steel column

M. Shahria Alam,A.H.M. Muntasir Billah,Shahriar Quayyum,Mahmud Ashraf,A.N.M. Rafi,Ahmad Rteil 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.6

The behaviour of steel column at elevated temperature is significantly different than that atambient temperature due to its changes in the mechanical properties with temperature. Reported literaturesuggests that steel column may become vulnerable when exposed to fire condition, since its strength andcapacity decrease rapidly with temperature. The present study aims at investigating the lateral load resistanceof non-insulated steel columns under fire exposure through finite element analysis. The studied parametersinclude moment-rotation behaviour, lateral load-deflection behaviour, stiffness and ductility of columns atdifferent axial load levels. It was observed that when the temperature of the column was increased, there wasa significant reduction in the lateral load and moment capacity of the non-insulated steel columns. Moreover,it was noted that the stiffness and ductility of steel columns decreased sharply with the increase intemperature, especially for temperatures above 400°C. In addition, the lateral load capacity and the momentcapacity of columns were plotted against fire exposure time, which revealed that in fire conditions, thenon-insulated steel columns experience substantial reduction in lateral load resistance within 15 minutes offire exposure.