Zerfall von 1-n-Butylaminocyclohexyl-phosphonsäure-di-n-butylester (Buminafos) in wäßrigem Medium

Degradation of n-Butylaminocyclohexyl phosphonic Acid di-n-Butylester (Buminafos) in Aqueous Medium . In aqueous medium, breakdown of Buminafos ( 1 ) is connected with total loss of its herbicidal activity. The phosphorus-carbon bond is cleaved and n-butylcyclohexylidene amine ( 3 ), cyclohexanone ( 5 ), phosphoric acid mono-n-butyl ester ( 4 ) (partly as n-butylamine salt), and 1-aminocyclohexyl phosphonic acid di-n-butylester ( 8 ) were found as degradation products of carbon-14 labeled Buminafos. Identification was performed by MS, GC/MS, ¹H- and ³¹P-n.m.r. spectroscopy, by detection of phosphorus, and by means of the radioactivity.     

Investigations on High Amylose Corn Starch Films. Part 3: Stress Strain Behaviour

By autoclaving a watery high amylose corn starch suspension, homogenous and isotrope films were obtained with different processing parameters. The films were used for investigations on the stress strain behavior. A systematical dependence on the water content and the relationship between native lipids and the starch chains was observed. Especially for films obtained from defatted corn starch, a clear transition was obtained, depending on the water content, from a brittle behavior far below the glass transition temperature T_G with a very high Youngsmodulus to a ductile failure behavior above T_G. The results led to a microscopical model for the native high amylose corn starch films, which in addition outlines the very interesting possibility of controlling in detail changes of the macroscopic stress strain behavior through variations on a molecular scale.     

Characteristics of Bi-metallic Interfaces Formed During Direct Energy Deposition Additive Manufacturing Processing

Metallurgical and Materials Transactions B - Various additive manufacturing processes are being evaluated to reduce the time and cost for fabrication of low volume, complex, and multifunctional...     

A coagulase-negative variant of Staphylococcus aureus from bovine mastitis milk

Bacteriological analysis of milk samples from quarters of a dairy cow suffering from subclinical mastitis yielded two isolates of Staphylococcus aureus which gave a negative reaction in the standard coagulase test. Both isolates were also clumping factor and thermonuclease negative, and gave a negative reaction in the Staphaurex? test. The isolates were identified by using commercial biochemical systems, and by PCR analysis of different staphylococcal cell surface protein and exoprotein genes. Further molecular identification of the isolates, which included sequencing of the 16S rRNA gene and RT-PCR of coagulase (coa), clumping-factor (clfA) and thermonuclease (nuc) genes, was consistent with the diagnosis phenotypically 'coagulase-negative variant of Staph. aureus'. The fact that coagulase-negative Staph. aureus variants can occur in the context of intramammary infections in cattle may result in the incorrect diagnosis 'coagulase-negative staphylococci (CNS)' in routine mastitis diagnostic, at least in rare cases. To fully ensure correct species diagnosis, sequencing of the 16S rRNA gene and amplification of specific genes such as coa is necessary in these cases.     

TBA studies of prepreg curing behavior

The torsional braid analysis (TBA) equipment has been used as an automated torsion pendulum to characterize prepreg materials in the form of single ply strips (2-1/2 × 1/8 in.). Compared to the use of coated glass braids, the main difference was a marked weakening of the gelation mechanical damping peak in isothermal runs. However, prepreg materials consisting of epoxy resins on glass, carbon or aramid fibers were successfully run isothermally to provide gelation and vitrification times as a function of temperature, or in constant heating rate scans to reveal the T < T_g and the T_g relaxations of the uncured resins, and at higher temperatures phenomena associated with gelation, vitrification and devitrification.     

Adsorption onto fluidized powdered activated carbon flocs-pACF

This work presents a new adsorption technique where the adsorbent (powdered activated carbon-PAC) is in the form of suspended flocs formed with water-soluble polymer flocculants. Thus, the adsorption of a typical dye, methylene blue (MB), was studied onto polyacrylamide flocs of PAC (PACF) in a fluidized bed reactor. The technique is based on the fact that the adsorption capacity of PAC does not decrease after flocculation because the adsorbed polymer occupies only a few surface sites, in the form of trains, loops, and tails. Moreover, the adsorption was found to proceed through a rapid mass transfer of MB to the adsorbing PAC flocs, in the same extent as onto PAC. Because of the rapid settling characteristics of the aggregates formed, the two phase separations, loaded PAC and solution, become easier. Thus, the technique offers the advantages of conducting simultaneously both adsorption and solid/liquid separation all in one single stage. Results obtained showed that high MB removal values can be attained in a fluidized bed reactor (>90%) and that PACF presents a much higher adsorption capacity (breakthrough points) than granulated activated carbon (GAC) in the same adsorbing bed. It is believed that this technique highly broadens the potential of the use of powdered activated carbon or other similar ultrafine adsorbents.     

Reaction Sequence and Microstructrual Development of CeO2-Doped Reaction-Bonded Mullite

A promising technique for the fabrication of mullite ceramics and mullite-matrix composites with low dimensional changes ("near-net-shape processing") is reaction bonding using Si metal and α-Al₂O₃ as starting materials, because sintering-induced shrinkage is compensated by Si-oxidation-induced volume expansion. A mullite reaction bonding (RBM) route which proceeds at much lower temperatures (lessthan equal to1350°C) than in conventional RBM systems (greaterthan equal to1500°C) is based on Ce doping which provides accelerated Si oxidation and mullite formation due to the formation of transient, low-viscosity Ce-Al-Si-O liquids. The present study shows that the required Ce-Al-Si-O liquids form in a reducing environment with Ce occurring as Ce³⁺. In an oxidizing environment, Ce is present as Ce⁴⁺, giving rise to precipitation of crystalline CeO₂. Ce³⁺ left and right arrow Ce⁴⁺ redox reactions in the temperature range under consideration appear to be controlled by the presence of nonoxidized Si in the samples. According to the present investigation the amount of CeO₂ added to the starting powders must be tailored carefully: Exaggerated CeO₂ content produces large amounts of low-viscosity Ce-Al-Si-O liquids which may have the disadvantage of excessive sealing of the open porosity. This slows the oxygen diffusion velocity into the specimen considerably, with the consequence that nonoxidized Si and a residual Ce-Al-Si-O glass coexist in the ceramics after processing. A solution to this problem is to simultaneously enhance mullite crystal growth through seeding which works against excessive liquid-phase-induced shrinkage of the samples. This in turn enables complete oxidation and recrystallization of all liquid phases.     

Male pheromone of swift moth,Hepialus hecta L. (Lepidoptera: Hepialidae)

(R)-6-Ethyl-2-methyl-2,3-dihydro-4H-pyran-4-one, (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3. 1]non-7-ene, and (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3.1]non-7-en-6-one represent the main components in the male pheromone of the swift moth,Hepialus hecta. The amounts of the three components were 40, 5, and 5 g per male, respectively. Structure elucidation of the compounds was based on spectroscopic data as compared to synthetic reference samples. The absolute configurations were determined by gas chromatography on chiral stationary phases; optically active samples served as reference compounds. Electrophysiological and behavioral experiments with natural material and synthetic samples clearly showed the three heterocyclic compounds to act as pheromones. (E, E)--Farnesene represents the main component of the scent secretion of maleHepialus humuli.     

Influence of growth conditions on biofilm development and mass transfer at the bulk/biofilm interface

In a long-term study on heterotrophic biofilms in tube reactors, this investigation focused on mass transfer at the bulk/biofilm interface, biofilm density and substrate conversion rates. Several biofilms were cultivated under different substrate and hydrodynamic conditions. Oxygen concentration profiles were measured with microelectrodes in the biofilm and in the boundary layer directly in the biofilm tube reactors. The thickness of the concentration boundary layer was found to depend on the surface structure of the biofilm. The hydrodynamic conditions and the substrate load during the growth phase of the biofilm in biofilm systems are two key parameters that influence the biofilm growth, particularly the structure, density and thickness. The measured substrate conversion rates, biofilm densities and the boundary layer thickness were used to formulate an equation for the mass transfer in biofilm tube reactors.     

Processing of the quench detection signals in W7-X

The Wendelstein 7-X (W7-X) project uses superconductive coils for generation of the magnetic field to keep the plasma. One of the important safety systems is the protection against quench events. The quench detection system of W7-X protects the superconducting coils, the superconducting bus bar sections and the high temperature superconductor of the current leads against the damage because of a quench and against the high stress by a fast discharge of the magnet system.Therefore, the present design of the quench detection system (QDS) uses a two-stage safety concept for discharging the magnetic system. This paper describes the present design of the system assembly from the quench detection unit (QDU) for the detection of the quench to the quench detection interface (QDI) to implement the two-stage safety concept.