Test Method for Purity of Styrene by Freezing Point Method

10.1520/d3799 ◽

2012 ◽

Author(s):

Keyword(s):

Freezing Point ◽

Point Method ◽

Test Method

Download Full-text

Fasteners at Low Temperatures: Characterization and Methods for Design

Volume 3: Design and Manufacturing ◽

10.1115/imece2011-63570 ◽

2011 ◽

Author(s):

Melanie Stephan ◽

Jens O. Weber ◽

Ulrich Wuttke ◽

Christina Berger

Keyword(s):

Impact Test ◽

Freezing Point ◽

Lattice Structure ◽

Detailed Examination ◽

Test Methods ◽

Climatic Conditions ◽

Test Method ◽

Design Concepts ◽

Ductile Behavior ◽

Pendulum Impact

Bolted joints are a major part of wind energy plants. Due to climatic conditions, they are often exposed to temperatures far below the freezing point. Together with the multiaxial state of stress, which results from the notch effect of the thread, and possible dynamic overloads during operation, sufficient ductility of the material is needed. The state of the art method to investigate the ductile behavior of fasteners is the Charpy pendulum impact test with a V-notched specimen. According to international standard DIN EN ISO 898-1 [1] respectively ASTM F568M-07 [2], fasteners made of carbon steel and alloy steel with a body centered cubic lattice structure can be used for temperatures down to 223 K (−50°C, −58°F) as long as a minimum impact energy of 27 J at 253 K (−20°C, −4°F) is met. As there are several disadvantages in using this test method for fasteners, a detailed examination of existing test methods and design concepts is necessary to find alternatives to the Charpy pendulum impact test. Extensive quasi-static and dynamic material tests were conducted on fasteners with property classes 5.6, 10.9 and 12.9 in a temperature range between 203 K (−70°C, −94°F) and room temperature 293 K (20°C, 68°F). Both mechanical properties and the influence of different specimen geometries were evaluated. Analytical concepts for the description of the low temperature applicability of different steels were analyzed.

Download Full-text

Effect of Prewetting Brines and Mixing on Ice-Melting Rate of Salt at Cold Temperatures: New Tracer Dilution Method

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2613-09 ◽

2017 ◽

Vol 2613 (1) ◽

pp. 71-78 ◽

Cited By ~ 3

Author(s):

Scott Koefod

Keyword(s):

Freezing Point ◽

Melting Rate ◽

Test Method ◽

Dilution Method ◽

Ice Melting ◽

Cold Temperatures ◽

Ice Melt ◽

Solid Salt ◽

Different Temperatures ◽

Tracer Dilution

A novel test method has been developed to measure the ice-melting rate of deicers. The ice-melting rates of prewetted salt were determined by measuring the change in the concentration of chloride (Cl−) or magnesium or calcium cations (Mg2+ or Ca2+, respectively) in the ice melt as tracers. The method is substantially more precise than the SHRP H205.1 standard and has the further advantage of measuring ice-melting and salt dissolution rates simultaneously. Brines were preequilibrated with ice at −19.3°C (−2.7°F) and blended with solid salt to determine the effect of different prewetting brines on the ice-melting rate of the solid salt component only. The measured equilibrium ice-melting capacity of sodium chloride (NaCl) agreed well with the theoretical value calculated from the NaCl freezing point curve. Under a condition of no mixing, solid salt yielded 0.87% of its total available ice-melting capacity after 60 min when wetted with NaCl brine and 9.7% when wetted with calcium chloride (CaCl2) brine. Mixing raised the yield of ice melt to 27.1% and 50.5% after 60 min when wet with NaCl and CaCl2 brines, respectively. The CaCl2 brine was slightly more effective than the magnesium chloride (MgCl2) brine at enhancing the ice-melting rate of salt. The test method promises to be a useful tool for permitting a more precise optimization of prewetting brine composition, concentration, and brine-to-salt ratio at different temperatures. The method may also permit better determination of the cost-effectiveness of different prewetting strategies and provide deeper insights into the mechanism of chemical ice melting.

Download Full-text