CFD Modeling of Wing and Body of an AUV for Estimation of Hydrodynamic Coefficients

Coefficients or hydrodynamic derivatives of autonomous underwater vehicles (AUVs) play a key role in their design and maneuverability. Using a suitable method to estimate these coefficients serves as a time efficient approach to raise the achievable precision in the design and control of AUVs. This paper estimates hydrodynamic derivatives of an AUV using computational fluid dynamics (CFD) for the wings and body. CFD modeling was performed to simulate captive model tests including straight line and planar motion mechanism (PMM). In such runs, the process was implemented separately for the wing and body. Experimental tests for the same AUV in the water tunnel were carried out for CFD validation. Comparing the numerical results to the experimental data, it was shown that the modeling method is able to estimate these coefficients at reasonable accuracy. The proposed modeling method was proved to be efficient in estimating hydrodynamic derivatives and hence can reduce associated computational costs with the process of detail design of AUVs

Angiotensin-converting enzyme inhibitor, Enalapril, inhibits tumor growth and potentiates the antitumor efficacy of 5-FU in colorectal cancer

OBJECTIVE: Colorectal cancer (CRC) is among the leading causes of cancer-related death, indicating the need for the identification of novel therapeutic approaches to increase the activity of current therapy or have better efficacy. Angiotensin-converting enzyme (ACE) is being reported to be associated with aggressive behaviors of CRC cells and poor prognosis. Here we explored the therapeutic potency of targeting ACE by Enalapril in CRC in vivo model. MATERIALS AND METHODS: A xenograft model of CRC was used to investigate the effects of Enalapril alone, or in combination with 5-FU, on tumor growth following histological staining (Hematoxylin and Eosin and Masson trichrome staining) and biochemical studies of Malondialdehyde (MDA), total thiols, superoxide dismutase (SOD) and catalase (CAT) activities. RESULTS: Enalapril reduced tumor growth and increased tumor necrosis; this effect was more pronounced in Enalapril plus 5-FU combination. Enalapril/5-FU was able to decrease tumor fibrosis and collagen content. ACE inhibitors also increased MDA level, as an oxidative stress marker, while reducing total thiol group levels, SOD and CAT enzyme activity. CONCLUSIONS: Our findings provide a novel insight on the therapeutic potential targeting of the renin–angiotensin system as a new therapeutic option in combination with current therapeutic agents 5-FU in the treatment of CRC

Slaughterhouse Wastewater Treatment by Combined Chemical Coagulation and Electrocoagulation Process

Slaughterhouse wastewater contains various and high amounts of organic matter (e.g., proteins, blood, fat and lard). In order to produce an effluent suitable for stream discharge, chemical coagulation and electrocoagulation techniques have been particularly explored at the laboratory pilot scale for organic compounds removal from slaughterhouse effluent. The purpose of this work was to investigate the feasibility of treating cattle-slaughterhouse wastewater by combined chemical coagulation and electrocoagulation process to achieve the required standards. The influence of the operating variables such as coagulant dose, electrical potential and reaction time on the removal efficiencies of major pollutants was determined. The rate of removal of pollutants linearly increased with increasing doses of PACl and applied voltage. COD and BOD5 removal of more than 99% was obtained by adding 100 mg/L PACl and applied voltage 40 V. The experiments demonstrated the effectiveness of chemical and electrochemical techniques for the treatment of slaughterhouse wastewaters. Consequently, combined processes are inferred to be superior to electrocoagulation alone for the removal of both organic and inorganic compounds from cattle-slaughterhouse wastewater

Fabrication of Al/Graphite/Al2O3 Surface Hybrid Nano Composite by Friction Stir Processing and Investigating The Wear and Microstructural Properties of The Composite

Friction stir processing was applied for fabricating an aluminum alloy based hybrid nano composite reinforced with nano sized Al2O3 and micro sized graphite particles. A mixture of Al2O3 and graphite particles was packed into a groove with 1 mm width and 4.5 mm depth, which had been cut in 5083 aluminum plate of 10 mm thick. Packed groove was subjected to friction stir processing in order to implement powder mixture into the aluminum alloy matrix. Microstructural properties were investigated by means of optical microscopy and scanning electron microscopy (SEM). It was found that reinforcement particle mixture was distributed uniformly in nugget zone. Wear resistance of composite was measured by dry sliding wear test. As a result, hybrid composite revealed significant reduction in wear rate in comparison with Al/AL2O3 composite produced by friction stir processing. Worn surface of the wear test samples were examined by SEM in order to determine wear mechanism

Influence of ultrasonic vibration on the microstructure and texture evolution of AZ91 magnesium alloy during ultrasonic-assisted friction stir welding

The aim of this work is to investigate the influence of ultrasonic vibration on the microstructure and texture evolution in ultrasonic-assisted friction stir welding (UaFSW) of AZ91 Mg alloy. Ultrasonic vibration with an amplitude of 15 µm induced to the weld line perpendicularly to the welding direction. A scanning electron microscopy equipped with electron backscattered diffraction (EBSD) was used to investigate the microstructure and texture changes of the joints. A high fraction of low-angle grain boundaries (LAGBs) was observed during the occurrence of dynamic recovery (DRV) in thermomechanically affected zones (TMAZs) of welded specimens. Statistical analysis from the grain boundaries of the stir zone (SZ) revealed that the fraction of high-angle grain boundaries (HAGBs) in the SZ of UaFSW joint is higher than that of the FSW joint. The results along with the formation of simple shear texture components in the SZ of welds imply that continuous dynamic recrystallization (CDRX) is responsible for grain refinement in the SZs. Moreover, vibration associated with UaFSW assisted the DRV and CDRX mechanisms and increases the intensity of the developed texture in the SZ of the UaFSW joint