Ingenieurwissenschaften und zugeordnete Tätigkeiten
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The safety characteristics of flammable gases and liquids are required when identifying potentially explosive mixtures and taking appropriate actions concerning explosion protection. Examples are given in this review of the safe handling and evaluation of hazards during the processing, storage, transport, and disposal of flammable liquids and gases. The CHEMSAFE database is presented as a reliable source of safety characteristic data, and ist new open-access version is introduced. CHEMSAFE currently contains assessed properties for about 3000 flammable liquids, gases and mixtures. The lack of a broad experimental foundation in the extensive field of non-atmospheric conditions shows the need for further investigation and standardization. This review summarizes experimental evidence and estimation methods for safety characteristic data under non-atmospheric conditions pointing out current limitations. Suggestions for pre-normative research on safety data under nonatmospheric conditions are given.
The wear rates of self-mated alumina couples show that friction as well as wear is largely determined by the above-mentioned hydro-thermal conditions. The presence of water and its amount available in the surrounding system either in liquid or in gaseous form plays a key role for friction and wear behavior and can be beneficial for the tribological profile of steam degradation resistant materials. Hot steam enhances the tribo-chemical formations of oxides and hydroxides on MgO-ZrO2 alumina and antimony impregnated carbon.
The present work deals with Niobcarbid (NbC). Strategic reflections on tungsten carbide and more and more stringent toxicological restrictions for cobalt associated for both with spiraling stock market prices have attracted recently some attention for Niobium carbide as a substitute for tungsten carbide in machining.
Comparison of Formaldehyde Concentrations in Emission Test Chambers Using EN 717-1 and EN 16516
(2018)
For more than 25 years EN 717-1 (Wood-based panels - Determination of formaldehyde re-lease - Part 1: Formaldehyde emission by the chamber method) is the standard for formalde-hyde emission testing of wooden boards. In 2017 EN 16516 (Construction products - Assess-ment of release of dangerous substances - Determination of emissions into indoor air) was published as a new harmonised standard for the emission testing of construction products. Because test chamber conditions are different, both standards give different concentrations for formaldehyde. To determine a conversion factor four test series were set up with different wooden boards. For a loading of 1 m²/m³ the conversion factor is 1.6. This means that the formaldehyde concentration measured under the conditions of EN 16516 is a factor of 1.6 higher compared to EN 717-1.
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.