G.c./m.s. investigations on living oligo(ethylene) species functionalized by oxygen

Living oligomers of ethylene obtained using sec-butyl-lithium complexed with tetramethylethylenediamine (TMEDA) were deactivated by oxygen. Mass spectrometry coupled with gas chromatography of the resulting product allowed the determination of the molecular mass distribution of the alcohols, the coupled products as well as the non-oxidized products formed.     

Rotary blanking: tool materials

The growing globalization leads to an increasing demand on competition between industrial companies. The manufacturing processes using innovative operations and advanced materials make it possible to develop a competitive power with a high level productivity. In this paper the process of rotary blanking is introduced as an innovative manufacturing method. It enables users to work more efficient and to reduce product costs with a high process speed. In order to understand this modern manufacturing technology, it is needed to analyze process parameters. In particular it is necessary to determine which materials are preferable for the rotary blanking. Therefore, the influence of different tool materials on the part quality was investigated through experiments. Experimental results of the rotary blanking from different tool materials are discussed and they are compared with the results of finite element simulations in this paper.     

X-Ray Diffraction Studies of Thermally Shocked Periclase

X-ray line profile analyses were used to study the effect of thermal shock on pericluse (MgO) powders of varied sieve size. Thermal shock does not produce significant microfragmentation; the crystallite size appeared to be ≥150 nm. Microstrain is very low at grain sizes < 0.10 mm, rises sharply up to ∼0.8 mm, and tends to saturate at ∼1 × 10⁻³ at sieve sizes above 3 mm.     

On the behaviour of concrete under water jet impingement

It is important from the economics point of view to understand the behaviour of concrete under loading due to plain water jets. Investigations which are based on mass removal measurements, grain size analysis, and mercury intrusion show that the performance of failure can be described using fracture mechanics methods. The reactions of hardened cement paste and concrete differ widely from each other because of the influence of interfaces between the cement paste and the aggregate.     

Pressen und Sintern von Molybdändisilizid

An Molybdändisilizidpulver mit rd. 63% Mo und 37% Si sowie mit Teilchengrößen von 0,2 bis 70 μm Untersuchung des Einflusses der Teilchengröße auf sein Preß- und Sinterverhalten sowie auf die Eigenschaften der Sinterkörper. Herstellung der Sinterkörper durch isostatisches Kaltpressen mit einem Druck von 10 kbar und anschließendes dreistündiges druckloses Sintern bei 1700 °C unter Wasserstoffgas.     

Methoden zur Bestimmung der Chinolizidinalkaloide in Lupinus mutabilis

Zusammenfassung Es werden Schnellmethoden zur Bestimmung der Gesamtalkaloide (photometrisch, titrimetrisch) und zur semi-quantitativen Bestimmung der Einzelalkaloide (dünnschichtchromatographisch) im Samen vonLupinus mutabilis beschrieben. Für die drei Schnellbestimmungsmethoden wird ein verbessertes Extraktionsverfahren dargestellt. Die Alkaloide werden in ihre Basen überführt, das Material wird mit basischem Aluminiumoxyd getrocknet und die Alkaloide mit Chloroform extrahiert.Bei der photometrischen Bestimmung der Gesamtalkaloide dient Bromkresolpurpur als Farbreagens. Zu ihrer titrimetrischen Bestimmung wird Tetrabromphenolphthaleinäthylester als Indikator benutzt. Die Einzelalkaloide werden semi-quantitativ, nach ihrer dünnschichtchromatographischen Trennung nach Anfärbung mit Dragendorffs Reagens bestimmt.Die drei Schnellmethoden sind für die Auslese alkaloidarmer Lupinen und zur Überwachung von technologischen Entbitterungsverfahren geeignet.

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Methods for the determination of quinolizidine alkaloide in lupinus mutabilisI. Screening Tests

Summary In this paper rapid procedures for the determination of total alkaloids (photometric, titrimetric) and for the semiquantitative determination of individual alkaloids (TLC) in the seeds ofLupinus mutabilis are presented. For all three methods an improved extraction procedure is employed. After transforming the alkaloids into their bases, the resulting material is dried with basic alumina and the alkaloids are extracted with chloroform.For the photometric determination of total alkaloids bromocresol purple is used as color reagent. The indicator for the titrimetric determination is tetrabromophenolphthalein ethyl ester. The individual alkaloids are evaluated semiquantitatively after Separation on TLC-plates and staining with Draggendorff reagent.All three screening tests are useful for the selection of low alkaloid Lupin strains and for the control of debittering processes.