Eine Synthese methylierter Epoxyhydroazulenone durch intramolekulare [4 + 3]-Cycloaddition einer aus 1,1-Dichloro-6-(3-methylfur-2-yl)hexan-2-on erzeugten Oxyallyl-Zwischenstufe

A synthesis of Methylated Epoxyhydroazulenones by Intramolecular [4 + 3] Cycloaddition of an Oxyallyl Intermediate, Generated from 1,1-Dichloro-6-(3-methyl-2-furyl)hexan-2-one (Z)-3-Methylpent-2-en-4-yn-1-ol ( 7 ) was transformed to 2-(4-chlorobutyl)-3-methylfuran ( 4b ) and 2-(but-3-enyl)-3-methylfuran ( 10a ) by C-alkylation and 5-exo-dig cyclization. The Grignard derivative formed from 4b gave 1,1-dichloro-6-(3-methylfur-2-yl)hexan-2-onc ( 1b ) on reaction with dichloroacetyl chloride. This dichloromethyl ketone undergoes a base-induced cyclization to form diastereoisomeric 7-chloro-1,2,3,6,7,8a-hexahydro-4-methyl-8H-3a,6-epoxyazulen-8-ones ( 3bα and 3bβ ) by way of an intramolecular [4+3] cycloaddition of an oxyallyl intermediate 2b. By dechlorination and hydrogenation of 3bβ , the tricyclic hydroepoxyazulenones 18 and 19 have been synthesized.     

Novel zeolite composites and consequences for rapid sorption processes

Novel sorbents for rapid dynamic sorption processes based on the concept of sorption-active shell/sorption-inert core composite granules are presented. Tailoring such composites to a technical sorption process is exemplified by NaX and LiLSX zeolites as sorption-active components. Composite granules are characterized by various techniques specifically by oxygen-VPSA pilot-scale tests and liquid-phase sorption experiments. The composite sorbents exhibit excellent potential for efficiency enhancement of existing processes by lowering investment and operating costs. This paper is dedicated to the memory of John D. Sherman     

Trapping of plasmons in ion holes

We present analytical and numerical studies of a new electron plasma wave interaction mechanism, which reveals trapping of Langmuir waves in ion holes associated with nonisothermal ion distribution functions. This Langmuir ion hole interaction is a unique kinetic phenomenon governed by two second nonlinear differential equations in which the Langmuir wave electric field and ion hole potential are coupled in a complex fashion. Numerical analyses of our nonlinearly coupled differential equations exhibit trapping of localized Langmuir wave envelops in the ion hole, which is either standing or moving with sub-or super ion thermal speed. The resulting ambipolar potential of the ion hole is essentially negative, giving rise to bipolar slow electric fields. The present investigation thus offers a new Langmuir wave contraction scenario that has not been rigorously explored in plasma physics.     

Nonlinear theory for a quantum diode in a dense Fermi magnetoplasma

We present a simple analytical nonlinear theory for quantum diodes in a dense Fermi magnetoplasma. By using the steady-state quantum hydrodynamical equations for a dense Fermi magnetoplasma, we derive coupled nonlinear Schr?dinger and Poisson equations. The latter are numerically solved to show the effects of the quantum statistical pressure, the quantum tunneling (or the quantum diffraction), and the external magnetic field strength on the potential and electron density profiles in a quantum diode at nanometer scales. It is found that the quantum statistical pressure introduces a lower bound on the steady electron flow in the quantum diode, while the quantum diffraction effect allows the electron tunneling at low flow speeds. The magnetic field acts as a barrier, and larger potentials are needed to drive currents through the quantum diode.     

Rut depth, soil compaction and rolling resistance when using bogie tracks

There are few studies of rolling resistance for bogie tracks on forestry machines. The aim of this study was to compare the effects of wheels and two types of bogie tracks on rut formation, cone index, and vehicle rolling resistance on some typical forest soils in Sweden. In an experiment, two types of tracks were put on a trailer with a bogie with hydraulic extension on the pulling bar giving the trailer repeatable travelling speed. Loads of 0 and 9.9 Mg were used on the trailer. The main results of this study are: Compared to rather wide and soft tires, tracks on the bogie reduced rut depth by up to 40% and cone index in the ruts by about 10%, although the tracks increased the mass on the trailer by 10–12%. The relative rolling resistance coefficient was not higher for tracks than for wheels. Further studies should be conducted to show the effect of track tension on rolling resistance and flotation and of the effects of tracks on heavy vehicles on subsoil compaction.     

UV excimer radiation from dielectric-barrier discharges

Dielectric-barrier (silent) discharges are ideally suited for efficient excitation of high-intensity UV radiation from excimers. The molecular continuum of xenon at 172 nm could be obtained with an efficiency of close to 10%. Model calculations for excimer formation and UV efficiencies in such discharges are presented. The possibility of obtaining many other wavelengths (e.g. KrF^* at 248 nm and XeCl^* at 308 nm) and the variety of conceivable geometries (plane or cylindrical) makes this new UV source an attractive choice for many photophysical and photochemical applications.     

Nonequilibrium volume plasma chemical processing

A review is presented of plasma chemical processes occurring in the volume part of electrical nonequilibrium discharges. The role of energetic electrons as initiators of chemical reactions in a cold background gas is discussed. Different discharge types of (glow, corona, silent, RF, and microwave discharges) are investigated with respect to their suitability for plasma processing. Emphasis is placed on the requirements of initiating and maintaining the discharge and, at the same time, optimizing plasma parameters for the desired chemical process. Using large-scale industrial ozone production as an example, the detailed process of discharge optimization is described. Other applications of volume plasma processing include other plasma chemical syntheses as well as decomposition processes such as flue gas treatment and hazardous waste disposal. The author only deals with plasmas which are not in equilibrium     

DSC studies of γ -irradiation influence on amylose-lipid complex transition in wheat flour

DSC studies were carried out in the heating-cooling cycles for non-irradiated and irradiated with -rays (⁶⁰Co) using 30 kGy dose wheat flour. The differences between gelatinisation and reversible transition of amylose-lipid complexes occurring in suspensions of non-irradiated and the irradiated flour (characterized by a dry matter to water ratio of 1:1 and 1:3) depend on the conditions applied in DSC measurements (concentration, heating/cooling rate) and on the preceding treatment of samples. An essential decrease in the temperature of amylose-lipid complex transition was discovered after irradiation. Retrogradation is inhibited in the dense gels of the irradiated samples as compared to the initial ones. The results are discussed in terms of radiation-induced destruction of the polysaccharide chains and lipid modification.