scholarly journals Improved Hole Wall Roughness and Corrosion Resistance of U-Shaped Hole Prepared by Casting

2021 ◽  
Author(s):  
Yingdong Qu ◽  
Yang Cao ◽  
Guanglong Li ◽  
Ruirun Chen ◽  
Rongde Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Water Channel ◽  
Aluminum Matrix ◽  
Cooling Water ◽  
Experimental Temperature ◽  
Wall Roughness ◽  
Cooling Channel ◽  
Hole Wall ◽  
Starting Point ◽  
Shaped Hole

Abstract The corrosion resistance of the cooling water channel in the water-cooled mold has an important impact on the application of the mold. In this paper, the influence of experimental temperature on roughness and corrosion resistance of U-shaped cooling channels prepared by casting is analyzed in detail. The results show that the experimental temperature increased from 998K to 1048K, the hole wall roughness of the U-shaped hole decreased from 83.264 to 76.287. However, the hole wall roughness increased with a further increase in temperature. Because the low experimental temperature will promote the formation of micro bulges and river ripples on the hole wall. However, with the temperature gradually increased, it will promote the aluminum matrix to react with the carbon fiber, which will increase the roughness. The corrosion performance analysis results show that a reasonable experimental temperature is beneficial to reduce the roughness of the hole wall and improve the corrosion resistance of the cooling channel. When the roughness is large, the ravines on the rough surface are easy to be the starting point of corrosion. At the same time, it is easy to cause the aggregation of Si elements to the hole wall at high experimental temperature, which will also cause corrosion. As a result, reasonable experimental temperature plays an important role in improving the corrosion resistance of the U-shaped cooling channel.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

scholarly journals Predicting the Structure and Dynamics of Membrane Protein GerAB from Bacillus subtilis

2021 ◽  
Vol 22 (7) ◽  
pp. 3793
Author(s):  
Sophie Blinker ◽  
Jocelyne Vreede ◽  
Peter Setlow ◽  
Stanley Brul
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Protein ◽  
Spore Germination ◽  
Structural Information ◽  
Transmembrane Protein ◽  
Homology Modelling ◽  
Water Channel ◽  
Md Simulations ◽  
Integral Membrane Protein ◽  
Starting Point

Bacillus subtilis forms dormant spores upon nutrient depletion. Germinant receptors (GRs) in spore’s inner membrane respond to ligands such as L-alanine, and trigger spore germination. In B. subtilis spores, GerA is the major GR, and has three subunits, GerAA, GerAB, and GerAC. L-Alanine activation of GerA requires all three subunits, but which binds L-alanine is unknown. To date, how GRs trigger germination is unknown, in particular due to lack of detailed structural information about B subunits. Using homology modelling with molecular dynamics (MD) simulations, we present structural predictions for the integral membrane protein GerAB. These predictions indicate that GerAB is an α-helical transmembrane protein containing a water channel. The MD simulations with free L-alanine show that alanine binds transiently to specific sites on GerAB. These results provide a starting point for unraveling the mechanism of L-alanine mediated signaling by GerAB, which may facilitate early events in spore germination.

scholarly journals CFD Analysis of Urban Canopy Flows Employing the V2F Model: Impact of Different Aspect Ratios and Relative Heights

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Fabio Nardecchia ◽  
Annalisa Di Bernardino ◽  
Francesca Pagliaro ◽  
Paolo Monti ◽  
Giovanni Leuzzi ◽  
...  
Keyword(s):  
Flow Field ◽  
Water Channel ◽  
Flow Regimes ◽  
Two Dimensional ◽  
Mean Flow ◽  
Ansys Fluent ◽  
Practical Applications ◽  
Aspect Ratios ◽  
Starting Point ◽  
Step Down

Computational fluid dynamics (CFD) is currently used in the environmental field to simulate flow and dispersion of pollutants around buildings. However, the closure assumptions of the turbulence usually employed in CFD codes are not always physically based and adequate for all the flow regimes relating to practical applications. The starting point of this work is the performance assessment of the V2F (i.e., v2¯ − f) model implemented in Ansys Fluent for simulating the flow field in an idealized array of two-dimensional canyons. The V2F model has been used in the past to predict low-speed and wall-bounded flows, but it has never been used to simulate airflows in urban street canyons. The numerical results are validated against experimental data collected in the water channel and compared with other turbulence models incorporated in Ansys Fluent (i.e., variations of both k-ε and k-ω models and the Reynolds stress model). The results show that the V2F model provides the best prediction of the flow field for two flow regimes commonly found in urban canopies. The V2F model is also employed to quantify the air-exchange rate (ACH) for a series of two-dimensional building arrangements, such as step-up and step-down configurations, having different aspect ratios and relative heights of the buildings. The results show a clear dependence of the ACH on the latter two parameters and highlight the role played by the turbulence in the exchange of air mass, particularly important for the step-down configurations, when the ventilation associated with the mean flow is generally poor.

scholarly journals Corrosion processes in cooling towers

2013 ◽  
Vol 12 (3) ◽  
pp. 231-238
Author(s):  
Teresa Szymura ◽  
Wojciech Adamczyk
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Structural Steel ◽  
Ammonium Sulfate ◽  
Ammonium Chloride ◽  
Cooling Tower ◽  
Cooling Water ◽  
Corrosion Testing ◽  
Electrochemical Methods ◽  
Cooling Towers

Corrosion testing was performed on structural steel of a cooling tower in the environment of cooling water containing ammonium sulfates and ammonium chloride. The test were performed using gravimetric and electrochemical methods with the application of a potentiostat. The analyses clearly showed that the corrosion rate is higher in solutions that contain ammonium sulfate and that the S235JRG2 steel exhibits higher corrosion resistance in this environment.

Study on Corrosion Resistance of Brass in Circulating Cooling Water with Different Concentration Ratio

2012 ◽  
Vol 511 ◽  
pp. 70-73
Author(s):  
Yu Chun Li ◽  
Xiao Wei Liu ◽  
Rui Feng Zhang ◽  
Kang Juan ◽  
Fan Gao
Keyword(s):  
Weight Loss ◽  
Corrosion Resistance ◽  
Concentration Ratio ◽  
Water System ◽  
Cooling Water ◽  
Cooling Water System ◽  
Circulating Cooling Water ◽  
Weight Loss Method ◽  
Ratio Condition ◽  
Loss Method

Abstract: The corrosion resistance of brass H70-1A cooling water was studied through weight-loss method and electrochemistry measurement in different concentration ratio condition. The results obtained from this study showed that brass inhibitor was necessary to add to circulating cooling water system when concentration ratio was in the range of 3~7.

Application Performance of Super Ferrite Stainless Steel on Condenser in Power Plant

2014 ◽  
Vol 651-653 ◽  
pp. 3-6
Author(s):  
Xiao Rui Guan ◽  
Da Lei Zhang ◽  
You Hai Jin
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Power Plant ◽  
Mechanical Test ◽  
Cooling Water ◽  
Electrochemical Test ◽  
Application Performance ◽  
Shock Resistance ◽  
Rate Of Cooling ◽  
Better Than

The application performances of TA2 titanium\S44660 super ferrite stainless steel\B30 cupronickel, which are widely used in power plant, were researched using electrochemical test and mechanical test. The results show that corrosion resistance of B30 is significantly lower than TA2 and S44660. Besides, corrosion resistance of S44660 is superior to TA2. Yield strength and tensile strength of S44660 is higher than TA2 and B30. When considering thickness of cooling tubes, flow rate of cooling water and clean coefficient, the thermal conductivity of three materials have little differences. The shock resistance of S44660 is better than TA2 and B30. S44660 contains a small amount of Ni, which improves greatly the anti-cracking ability of the base metal and welding bead.

Numerical Simulation Investigation on the Temperature Field Distribution and Variations in Hot Stamping Process

2010 ◽  
Vol 44-47 ◽  
pp. 992-996
Author(s):  
Lei Zhang ◽  
Guo Qun Zhao ◽  
Hui Ping Li
Keyword(s):  
Temperature Field ◽  
Field Distribution ◽  
Hot Stamping ◽  
Water Channel ◽  
Cooling Water ◽  
Temperature History ◽  
Temperature Field Distribution ◽  
Finite Element Software ◽  
Stamping Process ◽  
Die Surface

With finite element software Abaqus, a coupled thermal mechanical simulation of hot stamping process of U-Channel part using high strength steel was performed. Through the analysis of the temperature field distribution on the die surface, the influence of contact state between die and blank on the temperature field distribution was discussed. With temperature history curve of a selected node on die corner, the heat flow on two contact boundaries (die surface and cooling water channel surface) was discussed and its effects rules on the die temperature were given.

Structure Optimization Design about the Wet Grinding Sanding Machine with Double Cooling System

2014 ◽  
Vol 685 ◽  
pp. 208-211
Author(s):  
Shi Yang Wei ◽  
Guang Zhen Cheng ◽  
Zhe Tong ◽  
Jia Hang Ma ◽  
Yan Chun Gu ◽  
...  
Keyword(s):  
Optimization Design ◽  
Material Handling ◽  
Bending Strength ◽  
Cooling System ◽  
Low Cost ◽  
Water Channel ◽  
Cooling Water ◽  
Cylinder Liner ◽  
Wet Grinding ◽  
Working Volume

This paper introduced a wet grinding sanding machine, it is used for fine material. The machine was consists of three parts by stirring grated agencies, cooling system, material handling systems. Rotor and its Rod pin using the whole cast structure, low cost, conical rod pin to improve bending strength. Annular space between the cylinder and the cylinder liner formed cylinder cooling water channel, it connected respectively inlet and return pipes. Hollow spindle, inner pipe, pipe joint and rotor cavity form rotor cooling water channel, dual cooling effect is good. Shell fixed to the cylinder, turn the handle nut, interaction between the thread and the external thread on the piston, forces the pistons to axial movement, used to adjust the working volume and pressure of sanding machine.

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