A Comparative Study of Pyrolysis Liquids by Slow Pyrolysis of Industrial Hemp Leaves,Hurds and Roots

This study assessed the pyrolysis liquids obtained by slow pyrolysis of industrial hemp leaves, hurds, and roots. The liquids recovered between a pyrolysis temperature of 275–350 °C, at two condensation temperatures 130 °C and 70 °C, were analyzed. Aqueous and bio-oil pyrolysis liquids were produced and analyzed by proton nuclear magnetic resonance (NMR), gas chromatography–mass spectrometry (GC-MS), and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). NMR revealed quantitative concentrations of the most abundant compounds in the aqueous fractions and compound groups in the oily fractions. In the aqueous fractions, the concentration range of acetic acid was 50–241 gL⁻¹, methanol 2–30 gL⁻¹, propanoic acid 5–20 gL⁻¹, and 1-hydroxybutan-2-one 2 gL⁻¹. GC-MS was used to compare the compositions of the volatile compounds and APPI FT-ICR MS was utilized to determine the most abundant higher molecular weight compounds. The different obtained pyrolysis liquids (aqueous and oily) had various volatile and nonvolatile compounds such as acetic acid, 2,6-dimethoxyphenol, 2-methoxyphenol, and cannabidiol. This study provides a detailed understanding of the chemical composition of pyrolysis liquids from different parts of the industrial hemp plant and assesses their possible economic potential.     

Excitation energy transfer in isolated chlorosomes from Chlorobaculum tepidum and Prosthecochloris aestuarii

Excitation energy transfer in chlorosomes from photosynthetic green sulfur bacteria, Chlorobaculum (Cba.) tepidum and Prosthecochloris (Pst.) aestuarii, have been studied at room temperature by time-resolved femtosecond transient absorption spectroscopy. Bleach rise times from 117 to 270 fs resolved for both chlorosomes reflect extremely efficient intrachlorosomal energy transfer. Bleach relaxation times, from 1 to 3 ps and 25 to 35 ps, probed at 758 nm were tentatively assigned to intrachlorosomal energy transfer based on amplitude changes of the global fits and model calculations. The anisotropy decay constant of about 1 ps resolved at 807 nm probe wavelength for the chlorosomes from Chloroflexus aurantiacus, Pst. aestuarii and Cba. tepidum was related to energy transfer between bacteriochlorophyll a molecules of the baseplate and partly to intrachlorosomal energy transfer. The longer anisotropy components 6.6, 8.8 and 12.1 ps resolved for the three chlorosomes, respectively, were assigned to chlorosome to baseplate energy transfer. Global fits of magic-angle data also revealed longer chlorosome to baseplate energy transfer components from 95 to 135 ps, in accord with results from simulations.     

The role of hornification in the disintegration behaviour of TEMPO-oxidized bleached hardwood fibres in a high-shear homogenizer

The effect of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation on the structure of hornified fibres and their disintegration behaviour was studied by a method combining gradual disintegration of the fibre structure in an in-line homogenizer with a chromatographic separation technique. It was seen that hornification prior to TEMPO-mediated oxidation had a notable effect on the disintegration behaviour of bleached cellulose fibres in a high-shear homogenizer and on the properties of the resulting particles. Field-emission scanning electron microscopy imaging of the suspensions and viscosity and transmittance measurements revealed that never-dried oxidized fibres disintegrated into bunches of microfibrils and at higher charge densities into thinner and more individual microfibrils. These microfibrils were obtained from fibres through swelling and ballooning. The hornified fibres were mainly cut into shorter ones as the charge density increased. After reversing the hornification and allowing the fibres to swell further, however, microfibrils were also obtained from this source. The charge threshold for efficient microfibril production from never-dried fibres in the high-shear homogenizer used here was 0.7 mmol/g.     

Commutator anomalies and the Fock bundle

We show that the anomalous finite gauge transformations can be realized as linear operators acting on sections of the bundle of fermionic Fock spaces parametrized by vector potentials, and more generally, by splittings of the fermionic one-particle space into a pair of complementary subspaces. On the Lie algebra level we show that the construction leads to the standard formula for the relevant commutator anomalies.     

Anodic stripping voltammetry with a symmetric double-step waveform

The high sensitivity of differential pulse anodic stripping voltammetry (d.p.a.s.v.) is based on discrimination against the charging current by using short current-sampling periods near the end of the applied pulses. In this paper, the capacitive current is eliminated by using a symmetric double-step waveform superimposed on the voltage ramp. The areas under the adjacent current peaks are subtracted from each other which effectively cancels the contribution of the double-layer charging current but preserves the changes in the faradaic current. By using a mercury thin-film electrode the base line is reasonably flat down to nanomolar levels of Cd, Cu and Pb with a deposition time of 3–5 min. Compared with d.p.a.s.v., the proposed method has the advantages of a higher scan rate and simple electronic circuitry.     

New 2,2′-Bipyridine Derivatives and Their Luminescence Properties with Europium(III) and Terbium(III) Ions

Twenty differently substituted 2,2′,2″,2? -[(2,2′-bipyridine-6,6′-diyl)bis(methylenenitrilo)]tetrakis(acetc acids) 75–94 were synthesized with the purpose of developing new markers to be used in bioaffinity assays based on the unique luminescence properties of Eu^III and Tb^III ions. The relative luminescence yields, excitation maxima, and emission decay constants were determined for the corresponding Eu^III and Tb^III chelates. The substituents at the bipyridine moiety had a significant effect on the luminescence properties: the best relative luminescence yields R were obtained for ligands with electron-donating substituents (e.g. Me, Ph), electron-withdrawing substituents (e.g. NO₂, COOH) had a reverse effect. However, no clear correlation between the relative luminescence yields and the substituent parameters was found.     

Influence of Chelating Groups on the Luminescence Properties of Europium(III) and Terbium(III) chelates in the 2,2′-bipyridine series

Eight different 2,2′-bipyridine derivatives, i.e. 2, 5, 8, 10, 12, 13, 15 , and 19 (Schemes 1 and 2), were prepared to study the influence of the chelating groups on the luminescence properties of their Eu^III and Tb^III chelates. According to our luminescence results, 2,2′-(methylenenitrilo)bis(acetic acid) as well as (methylenenitrilo)bis-(methylphosphonic acid) in 6- and 6′-position of 2,2′-bipyridine is a suitable group when developing luminescent markers for bioaffinity assays based on time-resolved luminescence measurement.     

Deformation of current algebras in 3+1 dimensions

It was shown in an earlier paper that there is an Abelian extension of the general linear algebra gl ₂, that contains the current algebra with anomaly in 3+1 dimensions. We construct a three-parameter family of deformations of . For certain choices of the deformation parameters, we can construct unitary representations. We also construct highest-weight nonunitary representations for all choices of the parameters.This work was supported in part by U.S. Department of Energy Contract No. DE-AC02-76ER13065.