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- Biofuels (3)
- Polyethylene grades (3)
- Change in MFR and tensile properties (2)
- Coating (2)
- Compatibility (2)
- NO2 (2)
- Ringversuch (2)
- Spurenverunreinigungen (2)
- ATR-FTIR (1)
- Al2O3 (1)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (2)
- 1.4 Prozessanalytik (2)
- 3 Gefahrgutumschließungen; Energiespeicher (1)
- 3.2 Gefahrguttanks und Unfallmechanik (1)
- 4 Material und Umwelt (1)
- 4.5 Kunst- und Kulturgutanalyse (1)
- 5 Werkstofftechnik (1)
- 5.6 Glas (1)
- 7 Bauwerkssicherheit (1)
- 7.6 Korrosion und Korrosionsschutz (1)
Resistance to oxidative degradation by nitric acid has been selected for a comparison of polyethylene grades in a European standard on suitability proof for alternative plastic resins used for packagings and intermediate bulk containers (IBCs) for the transport of dangerous goods. Measurements of the infrared (IR) absorption spectra of microtome slices cut from the walls of jerricans, which were pre-stored with 55% nitric acid for 21 and 42 days at 40°C, showed changes in the structure of the polyethylene. The penetration depths of 55% nitric acid into the polyethylene grades are, in principle, suitable for evaluating the resistance to oxidative degradation of polyethylene grades after pre-storage of the packagings for 21 days. After this period the packaging wall is not fully penetrated. The intensities of the IR bands at 1565 cm-1 (-NO2), 1630 cm-1 (-C=C) and 1654 cm-1 (-O-NO2) increased with the treatment time with 55% nitric acid as a result of oxidative damage by the nitric acid. The high increase in absorbance of the -C=C band in the region 1630 - 1690 cm-1 is attributable to paraffinic chain cracks. The absorbance of the -O-NO2 band, formed as result of the nitration process was still low at a test temperature of 40°C.
Inorganic phosphorus and nitrogen-phosphorus-potassium (NPK) fertilizers based on phosphates from thermochemically treated sewage sludge ash were analyzed using mid-infrared (mid-IR) and far-infrared (FIR) spectroscopy. The different compounds present in the fertilizers were qualitatively determined with the help of recorded reference spectra of pure substances. Differentiation between various phosphates and other compounds such as sulfates, nitrates, and oxides was possible using combined interpretation of the mid-IR and FIR spectra. The results are in agreement with previous X-ray diffraction (XRD) measurements of the same samples. The main phosphate phases detected were NH4H2PO4, MgHPO4·3H2O, Mg3(PO4)2, Ca5(PO4)5Cl, CaHPO4·2H2O, Ca(H2-PO4)2·H2O, and AlPO4. Furthermore, K2SO4, NH4NO3, Fe2O3, and SiO2 were identified in the IR spectra. However, ammonium and sulfate compounds were only identified in the mid-IR region but were not detectable in the FIR region.
The suitability of an Al2O3 coating for corrosion protection on X20Cr13 was evaluated in various artificial geothermal brines, focusing on the influence of different pH (4, 6 and 8) and their chemical compositions on the coating properties. All experiments were performed in the laboratory using autoclaves at 150 ◦C and 1 MPa in deaerated condition for 1 and 7 days. Results showed that the pH of geothermal waters is the most detrimental factor in the transformation of ɣ-Al2O3 and its protective abilities. Delaminations were found in the Coating exposed to geothermal brines with pH 4. FTIR spectra indicated a transformation of ɣ-Al2O3 to boehmite AlOOH after exposure to pH 4 and 6, and bayerite Al(OH)3 was formed after exposure to pH 8. Different Crystal structures of the hydrated Al2O3 also contribute to the stability of the coatings, observed by the SEM- EDX of the surface and cross-section of coatings. This study indicated that ɣ-Al2O3 sol-gel coating presents a promising aspect of corrosion protection in geothermal environment with a neutral pH.
Biofuels including ethanol and biodiesel (FAME) represent a renewable fuel alternative to petroleum-derived transport fuels. The aim of this work was to study the interaction between high density polyethylene (HDPE) with permeation barriers in form of polyamide (PA) and fluorination, and biofuels such as E85 (fuel with 85 % ethanol), biodiesel and B10 (heating oil with 10 % biodiesel). 10 l jerrycans made of polyethylene with permeation barrier of PA were filled with E85 and biodiesel and exposed to temperatures of 20 °C and 40 °C for 5 years. Half of the 20 l jerrycans of HDPE for filling with B10 were fluorinated at the inner layer to prevent permeation before the exposure. Tensile properties were determined once a year, and FTIR-spectroscopy was used to evaluate possible changes.
The tensile properties tensile strength and breaking elongation of HDPE jerrycan cuttings with permeation barrier decreased, but not significantly, after immersion in E85, biodiesel and B10. The elasticity modulus of the polyethylene grades was especially reduced during exposure to E85.
The FTIR spectra of HDPE jerrycan cuttings with permeation barrier showed that immersion tests for five years with the test fuels at 20 °C and 40 °C did not lead to a decomposition of the permeation barriers.
This work presents the non-destructive spectroscopic characterisation of original Dead Sea Scrolls (DSS)parchment fragments from Ronald Reed collection. The fragments are of paramount importance becausethey have never been subjected to any treatment of preservation and restoration, this allows to investi-gate the manufacturing method of real original Jewish parchments. The manufacture of “sacred” Jewishparchments, in fact, is traditionally supposed to use a superficial tannin treatment. To study the DSS frag-ments, it was necessary both to analyse mock-up samples, especially manufactured in order to reproduceancient Oriental Jewish ritual parchments, and to compare the results with those obtained in the analysisof modern and ancient Western Jewish ritual parchments, in order to test the effectiveness of the selectedspectroscopic techniques. Traditionally, the main difference between Oriental and Western traditionalparchment preparation consisted in the dehairing method: enzymatic for Oriental and lime-based forWestern. Moreover, a finishing treatment with tannin was supposed to be applied on ritual Jewish parch-ments. The need of reference samples derives from the knowledge that each parchment preparation,treatment and degradation can induce structural modifications that affect the spectral features. FourierTransform Infrared Spectroscopy by Attenuated Total Reflection (ATR-FTIR), FT-Raman and m-Ramanwere used in this study. The experimental results allowed us to recognise, with different sensitivity, thepresence of tannin by using m-Raman and IR spectroscopies and to prove that not all the archaeologicalsamples were manufactured in the same way with vegetal extracts. Many salts (tschermigite, dolomite,calcite, gypsum and iron carbonate) were found on the surface of DSS fragments. They can derive fromthe degradation processes and storage environment before the discovery or from the manufacture. More-over, the different sensitivities and instrumental characteristics of the used techniques permitted us toestablish an analytical protocol, useful for further studies of similar materials.
IR and Raman study of calcium aluminosilicate glasses of the composition xCaO.xAl2O3.(100-2x)SiO2
(2002)
Improved wetting of bare and pre-coated steels by aqueous alumina sols for optimum coating success
(2010)
Alumina coatings are a promising candidate for
the protection of metals prone to high temperature corrosion.
If applied via sol–gel process, especially by using so
called aqueous modified Yoldas-sols, the deposition is
hardened by differences in surface free energy of substrate
and sol. In this paper the apparent surface properties of
samples to be coated and sols were examined by contact
angle measurements, IR-spectroscopy and tensiometry.
The results imply, after consideration of possible uncertainties,
the use of surface tension reducing 2-butanol
already present during hydrolysis of the sols to obtain an
easy and successful coating process.