The effect of free fatty acid on the reactivity of copper-based catalysts for the hydrogenolysis of fatty acid methyl esters

In the synthesis of fatty alcohols by hydrogenolysis of fatty acid methyl esters, small amounts of free fatty acids in the feed negatively affect the reactivity of copper-silica based catalysts. The effect of the acid was investigated in relation to the production of water, the nature of the inhibiting species, and the degree of reduction of the catalyst. Inhibition is reversible and not due to catalyst deactivation. Water is not the inhibiting species. Furthermore, formation of copper and zinc soaps was excluded. Lauric acid in the methyl ester feed reacts preferentially, but at a lower rate than the ester. Inhibition most likely stems from a preferential adsorption of the acid at the active sites of the catalyst. The consequences for practical applications are discussed.     

Cover Image,Volume 68, Issue 2

The cover image is based on the Research Article Differential scanning calorimetry study of cross‐nucleation between polymorphs in isotactic poly(1‐butene) by Bao Wang et al. DOI: 10.1002/pi.5595 .

     

Soil science and the <Emphasis Type="Italic">h</Emphasis> index

Soil science is a relatively young and specialised field of science. This note discusses the use of the h index as a scientific output measure in soil science. We explore the governing factors of h index in soil science: the number of soil scientists, the number of papers published, the average number of citations, and the age of the scientist. We found the average relationship between h index and scientific age for soil science: h = 0.7 t. The h index for soil science is smaller than other major science disciplines but norms for h need to be established     

Stable Oxygen Isotopes for Tracing the Origin of Clogging in Continuous Casting Submerged Entry Nozzles

An approach for tracing the origin of submerged entry nozzle (SEN) clogging that occurs during continuous casting of Al‐killed steel is presented. This approach consists of using stable oxygen isotope ratios. IR laser fluorination in combination with gas mass spectroscopy is performed to determine the oxygen isotope composition of alumina‐rich precipitates (clogging) and possible oxygen sources like refractory materials, slags, process and atmospheric oxygen. Three oxygen sources for clogging are identified. A quantitative model is presented.     

Bauwerksüberwachung der Autobahnbrücke Gossensaß

Structural Monitoring of Concrete Bridges The condition assessment of aged structures is becoming a more and more important issue for civil infrastructure management systems. The continued use of existing systems is, due to environmental, economical and socio‐political assets, of great significance growing larger every year. In front of this background we find the necessity to identify the key parameters and procedures to verify and update the knowledge about the present condition of a structure. A visual inspection may yield a first qualitative, maybe purely intuitive impression. A better judgment would be based on the evaluation of acquired quantitative information. The present contribution is intended to describe the implementation as well as an excerpt of the fundamental results of the online‐monitoring‐system realized on the Gossensaß viaduct, addressing durability and serviceability aspects.     

Stochastische Parameteridentifikation bei Konstruktionsbeton für die Betonerhaltung

Probabilistic Response Identification and Monitoring of Concrete Structures The permanent supervision of structures, which is based on monitoring systems, has gained significance. It is a prior target to couple these supervision results with numeric methods that have the ability to derive the reliability of the structure and the time dependence of material parameters. The “Sensitivity Factor Evolution Method” and the “Neural Network Technology” offer the possibility of using the monitoring data for efficient preservation planning. In the following article these methodologies are introduced together with a brief yet necessary digression about the stochastic model formation of concrete.