To study the corrosion resistance of metals and alloys,
an analysis system needs to be able to simulate the harsh environments to
which these materials are subjected. The system must also collect data from
metal and alloy samples at elevated temperatures over long periods of time
(typically days). Thermogravimetric analyzers (TGs) are well accepted systems
for both corrosion studies and long-term elevated temperature studies. However,
until now, TGs could conduct either corrosion studies or long-term studies,
but not both. This paper presents a TG system specifically designed to satisfy
the requirements of long-term corrosion resistance studies of metals and alloys.
Authors:Umakant D. Pawar, Chandrakant D. Pawar, Rajendra R. Mavle, and Rajendra K. Pardeshi
.D. Sammons , P.C.C. Feng , F. Kohn , K. Kretzmer , A. Mehrsheikh , M. Bleeke , J.L. Honegger , D. Farmer , D. Wright , E.A. Haupfear , in V.K. Nandula (ed.), Glyphosate Resistance in Crops and Weeds: History, Development, and Management , Wiley
The present review deals with the radiation chemistry of dilute aqueous solutions of organic substances emphasizing the possibility of use of high energy radiation in wastewater treatment. Effects of radiation on biodegradability, toxicity to water organisms and changes in molecules of solutes showing resistance to biochemical degradation and toxicity to water organisms are discussed.
Composite sorbents based on potassium nickel ferrocyanide embedded in silica gel matrix were prepared and characterised by
powdered X-ray diffraction analysis, IR spectra, Mössbauer spectra and electron microscopy. The sorbent exhibits very good
efficiency for cesium uptake and radiation resistance. The sorption capacity for cesium ions is comparable with the capacity
for the pure ferrocyanides.
Authors:A. Ponomarenko, C. Klason, N. Kazantseva, M. Buzin, M. Alexandre, Ph. Dubois, I. Tchmutin, V. Shevchenko, and R. Jérôme
Thermogravimetry was used to investigate the effects of different inorganic functional fillers on the heat resistance of polymer
matrices. The kinetic parameters of thermal oxidative degradation were shown to depend on the polymer, the chemical composition
of the filler surface, the filler concentration, and the processing method, which determines the distribution of filler particles
in the polymer matrix. Magnetic fillers (carbonyl iron, and hexaferrites of different structural types) were shown to be chemically
active fillers, increasing the heat resistance of siliconorganic polymers. Their stabilizing effect is due to blocking of
the end silanol groups and macroradicals by the surface of the filler and non-chain inhibition of thermal oxidative degradation.
In the case of fiber-forming polymers (UHMWPE, PVOH and PAN), most magnetic fillers are chemically inert, but at concentrations
of 30–50 vol% they increase the heat resistance of the composite. Addition of carbon black increased the heat resistance of
the thermoplastic matrix. The dependence of the thermal degradation onset temperature on the kaolin concentration in the polyolefin
matrix exhibited a maximum. Analysis of the experimental results demonstrated the operating temperature ranges for different
composites, and their maximum operating temperature.
. (1995) Wear resistance tests of farm-machines materials. (in Hungarian).
Járművek és Mezőgazdasági Gépek
. Budapest, 1995/2/64–67.
Birkás, M., Dexter, A. R., Kalmár, T. Bottlik, L. (2006) Soil quality — soil
For the preservation of environment from radioactive contamination, one of the properties necessary for solidified radioactive wastes is resistance to the release of radionuclides due to leaching by ground water after land disposal. In order to seek the optimum solidifying formulation for cement solidified boric acid concentrate from pressurized water reactor, a variety of specimens were prepared, varying the content of neutralizing agents and neutralization methods. For the leaching measurements, the ANS 16.1 Standard Leach Test was carried out for the specimens which had been mixed with small concentration of137Cs to estimate the leachability index. According to our investigation, the optimum contents of neutralizing agents for neutralization of boric acid radioactive waste were determined in view of resistance ability to leaching. Eventually the leachability indices have turned out to be 5.807.91 depending on the formulations.
Triazines are a class of molecules which have been found in meteorites such as Orgueil meteorite. Despite their poor resistance
to UV radiation, these molecules survived millions of years inside a meteorite. The present work is dedicated to the examination
of the radiation resistance of the simplest sym-triazine: 1,3,5-triazine. The crystals of this molecule have been irradiated
with γ-radiation at 50 and 350 kGy and were studied by electronic absorption spectroscopy, liquid chromatography, FT-IR spectroscopy
and differential scanning calorimetry (DSC). All the data suggest the relatively low stability of this molecule to high energy
radiation. The resulting products from radiolysis are formamidine together with triazine dimers and oligomers. Other radiolysis
products are H2, CH4, HCN and other gases.
The thermal resistances of epoxy resins cured with complexes of boron trifluoride with benzylamine, 2-benzylaminoethanol and 2-anilinoethanol were examined. Thermal analysis data were used to compare the thermal resistances of epoxy compusitions cured with polyamines (aliphatic and aromatic), acid anhydrides and complexes of boron trifluoride with the above amines.
Authors:H. Rezaei, Y. Choiset, P. Debey, J. Grosclaude, and T. Haertl
Well-defined set of sheep PrP polymorphisms at positions 136, 154 and 171 define susceptibility to scrapie, ranging from very high susceptibility observed for V136-R154-Q171 (VRQ) variant to resistance for A136-R154-R171 (ARR).To gain insight into the mechanisms of scrapie susceptibility/resistance, the unfolding pathways of the sheep prion protein variants were analysed by differential scanning calorimetry over a wide range of pH. Thermal unfolding occurs, in the 5.0 to 6.0 pH range, through a reversible one-step process while at pH<4.5 and >6.0 unfolding intermediates are formed, which are stable in the 65–80°C range. The observed differences correlate with ovine susceptibility to scrapie.