Slaking of coal measure rocks - Effect of water on mechanical properties of coal measure rocks. (3rd report).

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2.

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Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽

10.3390/ma14051261 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1261

Author(s):

Catarina S. P. Borges ◽

Alireza Akhavan-Safar ◽

Eduardo A. S. Marques ◽

Ricardo J. C. Carbas ◽

Christoph Ueffing ◽

...

Keyword(s):

Mechanical Properties ◽

Water Absorption ◽

Water Uptake ◽

Significant Influence ◽

Water Immersion ◽

Water Diffusion ◽

Polybutylene Terephthalate ◽

Chemical Changes ◽

Water Ingress ◽

Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

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Effects of depositional environment on rearranged hopanes in lacustrine and coal measure rocks

Journal of Petroleum Science and Engineering ◽

10.1016/j.petrol.2017.11.035 ◽

2018 ◽

Vol 169 ◽

pp. 785-795 ◽

Cited By ~ 4

Author(s):

Ting Kong ◽

Min Zhang

Keyword(s):

Depositional Environment ◽

Coal Measure ◽

Coal Measure Rocks

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Time Effect of Water Injection on the Mechanical Properties of Coal and Its Application in Rockburst Prevention in Mining

Energies ◽

10.3390/en10111783 ◽

2017 ◽

Vol 10 (11) ◽

pp. 1783 ◽

Cited By ~ 15

Author(s):

Xiaofei Liu ◽

Guang Xu ◽

Chong Zhang ◽

Biao Kong ◽

Jifa Qian ◽

...

Keyword(s):

Mechanical Properties ◽

Water Injection ◽

Time Effect ◽

Effect Of Water

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Effect of Water Vapor/Hydrogen Environments on Niobium, B-66 Niobium Alloy, Tantalum, and Ta-10W Alloy

CORROSION ◽

10.5006/1.3585255 ◽

1991 ◽

Vol 47 (4) ◽

pp. 272-280

Author(s):

R. J. Walter ◽

G. G. Bentle ◽

W. T. Chandler

Keyword(s):

Mechanical Properties ◽

Experimental Investigation ◽

Water Vapor ◽

Complex Function ◽

Tensile Tests ◽

Niobium Alloy ◽

Hydrogen Environment ◽

Hydrogen Mixture ◽

Effect Of Water

Abstract The results of an experimental investigation of the effect of water vapor/hydrogen environments on the mechanical properties of niobium, B-66 niobium alloy, tantalum, and Ta-10W alloy are presented. Tensile tests were conducted on specimens of these materials in water vapor/hydrogen environments with water vapor/hydrogen mixture ratios of 1 and 3. The water vapor/hydrogen environment caused strength reductions on tantalum and Ta—WW and ductility reductions on all four materials. The degree and causes of embrittlement were a complex function of temperature.

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