Quantitative NMR analysis of the aqueous phase from hydrothermal liquefaction of lignin

Hydrothermal liquefaction (HTL) of biomass such as lignin could contribute to finding replacements for petroleum, both as a fuel and production of chemicals. The organic phase produced in formic acid assisted HTL of lignin has been extensively analyzed previously. The solid phase is routinely analyzed by elemental analysis, and the gas phase has also been studied. The aqueous phase, on the other hand, has received little attention so far and this paper aims to identify and quantify the organic compounds that remain in the aqueous phase after the workup of the organic phase. Using NMR with water suppression, this is achieved with simple sample preparation. The major components are identified using 2D NMR (HSQC spectra) together with proton spectra and 13C spectra as well as verification with standard samples. Their concentrations are determined based on 1H spectra with an added internal standard. An initial evaluation of the effect of temperature and catalyst in the formic acid assisted HTL is given to demonstrate the relevance of the approach. Methanol, formic acid, acetic acid, acetone, phenol, catechol, and dimethyl ether have been identified and quantified in aqueous samples from six different HTL-experiments. 76 %–86 % of the peak area of the proton spectra have been accounted for.publishedVersio

Studying Community Dynamics with an Incremental Graph Mining Algorithm

The widespread usage of the Web and later of the Web 2.0 for social interactions has stimulated scholars of different disciplines in studying electronic communities. Traditionally, communities are observed as a static phenomenon. However, they are evolving constellations, which emerge, lose members and obtain new ones and potentially, grow, coerce, split or decline. Such dynamic phenomena require the study of social networks across the time axis. We propose the graph mining algorithm DENGRAPH for the discovery and monitoring of evolving communities. Data mining methods are successfully used for community discovery but are mostly limited to the static perspective. Taking a dynamic perspective implies the study of a stream of interactions among community members. Accordingly, our DENGRAPH is an incremental graph mining algorithm, which detects and adapts communities over time. We report on our first results in applying DENGRAPH on the social network of mail interactions of ENRON

Formic acid assisted liquefaction of lignin in water and ethanol, investigated for a 0.025 and a 5 L batch reactor: Comparison of yields and compositions of the products

Formic acid assisted conversion of lignin to liquids (LtL-process), where lignin is hydrodeoxygenated in a one-step conversion, produces bio-oils with a molecular weight range of 300–600 Da that comprise a complex mixture of monomeric phenols, e.g., phenol, cresol, guaiacol, catechol, etc., and more hydrogenated products. This paper addresses depolymerisation of lignin at small and large lab scales and includes characterisation of the products. Lignin conversion is performed using a 5 L stirred reactor and a 0.025 L unstirred reactor to evaluate the effect of increased volume and stirring on the oil yield and oil quality. The amount of oil yields is investigated for different types of lignin/lignin-rich residues, reaction temperatures (320–380 °C), reaction times (0.75–3 h) and reaction solvents (aqueous or ethanolic), and have been shown to be highest for the 0.025 L reactor. Furthermore, the relationship between the yields and reaction conditions are systematically explored using principal component analysis (PCA). For the Eucalyptus lignin-rich residue, ethanol tends to give higher oil yields (36–52 wt%) at most of the operating temperatures compared to water as reaction solvent (20–50 wt%). At both reaction scales and both solvent-systems, oil yields tends to decrease at reaction temperatures above 350 °C due to increased char formation. Reaction time does not seem to have any significant effect on oil yield at either scale. More than 40 wt% of the input lignin can be recovered as oil at 320 °C at both scales and solvent systems.publishedVersio

The use of anthracene as a model compound in a comparative study of hydrous pyrolysis methods for industrial waste remediation

Polycyclic aromatic hydrocarbons are very stable compounds and tend to bioaccumulate in the environment due to their high degree of conjugation and aromaticity. Hydrous pyrolysis is explored as a technique for the treatment of industrial water containing PAH, using anthracene as a model compound. The reactivity of anthracene under a range of temperatures and durations are studied in this paper. Aliquots of 1.0-10.0mg of anthracene in a range of 1.0-5.0 mL of H(2)O are subjected to hydrous pyrolysis under varied conditions of temperature, reagents and duration. The conditions include oxidising systems comprising distilled water, hydrogen peroxide and Nafion-SiO(2) solid catalyst in water; and reducing systems of formic acid and formic acid/Nafion-SiO(2)/Pd-C catalysts to assess a range of redox reaction conditions. Oxygen in air played a role in some of the reaction conditions. Pyrolysed products were identified and quantified by the use of Gas Chromatography-Mass Spectrometry (GC-MS). The major products were anthrone, anthraquinone, xanthone from oxidation; and multiple hydro-anthracene derivatives from reductive hydogenation. The nature of reaction conditions influenced the extent of anthracene degradation. The products formed are more reactive (less stable) as compared to anthracene the starting material and will therefore be less persistent in the environment

Nachweis von Euterinfektionen in der Frühlaktation bei Milchziegen

Mastitis hat bei Milchziegen einen ähnlichen Stellenwert wie bei Milckühen, aber Indikatoren zur Mastitisfrüherkennung fehlen bisher. Die subklinische Form der Mastitis, die ohne äußerliche Symptome einer Entzündung verläuft, stellt eine stete Ansteckungsgefahr für den gesamten Bestand dar

Untersuchungen zu Euterinfektionen in der Frühlaktation bei Milchziegen

Mastitis hat bei Milchziegen einen ähnlichen Stellenwert wie bei Milchkühen, aber Indikatoren zur Mastitisfrüherkennung fehlen bisher. Ziel der vorliegenden Untersuchung ist daher die Ermittlung geeigneter Indikatoren für Euterinfektionen in der Frühlaktation von Milchziegen. In den ersten 6 Wochen der Laktation wurden wöchentlich Hälftengemelksproben von 60 Ziegen der Rasse Bunte Deutsche Edelziege entnommen und der Gehalt an somatischen Zellen (SZZ), der bakteriologische Status, die elektrische Leitfähigkeit und NAGase bestimmt. Weiterhin wurde der California-Mastitis-Test erhoben. Minor- und Majorpathogene wurden bei 47 % der Tiere identifiziert. 54 % der Infektionen waren auf KNS zurückzuführen. Die Ergebnisse zeigen einen Einfluss der Art des Erregers auf die SZZ und die NAGase Aktivität. Allerdings macht es die große Variation innerhalb beider Parameter schwierig, Grenzwerte für die Unterscheidung in infizierte und nichtinfizierte Euterhälften von Milchziegen festzulegen

Einfluss von Euterinfektionen auf Enzymaktivitäten in Ziegenmilch in der Frühlaktation

At present the analysis of somatic cell count (SCC) used for the detection of intramammary infections in cows is also recommended for goats, but due to various factors influencing SCC it allows only limited conclusions on the udder health of goats. The aim of the present study was to investigate the influence of infection status on different milk enzyme activities and SCC throughout the early lactation. 60 dairy goats were sampled at weekly intervals over a period of six weeks after kidding and the bacteriological status, milk SCC and the activity of N-acetyl-ß-D-glucosaminidase (NAGase), ß-glucuronidase (ß-glu) and lactate dehydrogenase (LDH) of udder halves were analysed. The infection status had a highly significant effect on SCC, ß-glu and LDH activity, but ß-glu was not influenced by the stage of lactation. Therefore the usefulness of ß-glu in the assessment of udder health status should be further proved

Hydrate Plugging and Flow Remediation during CO2 Injection in Sediments

Successful geological sequestration of carbon depends strongly on reservoir seal integrity and storage capacity, including CO2 injection efficiency. Formation of solid hydrates in the near-wellbore area during CO2 injection can cause permeability impairment and, eventually, injectivity loss. In this study, flow remediation in hydrate-plugged sandstone was assessed as function of hydrate morphology and saturation. CO2 and CH4 hydrates formed consistently at elevated pressures and low temperatures, reflecting gas-invaded zones containing residual brine near the injection well. Flow remediation by methanol injection benefited from miscibility with water; the methanol solution contacted and dissociated CO2 hydrates via liquid water channels. Injection of N2 gas did not result in flow remediation of non-porous CO2 and CH4 hydrates, likely due to insufficient gas permeability. In contrast, N2 as a thermodynamic inhibitor dissociated porous CH4 hydrates at lower hydrate saturations (<0.48 frac.). Core-scale thermal stimulation proved to be the most efficient remediation method for near-zero permeability conditions. However, once thermal stimulation ended and pure CO2 injection recommenced at hydrate-forming conditions, secondary hydrate formation occurred aggressively due to the memory effect. Field-specific remediation methods must be included in the well design to avoid key operational challenges during carbon injection and storage.publishedVersio

Seebeck coefficients of half-metallic ferromagnets

In this report the Co2 based Heusler compounds are discussed as potential materials for spin voltage generation. The compounds were synthesized by arcmelting and consequent annealing. Band structure calculations were performed and revealed the compounds to be half-metallic ferromagnets. Magnetometry was performed on the samples and the Curie temperatures and the magnetic moments were determined. The Seebeck coefficients were measured from low to ambient temperatures for all compounds. For selected compounds high temperature measurements up to 900 K were performed.Comment: accepted contribution o the Special Issue "Spin Caloritronics" of Solid State Communication