Search results for "Mechanical engineering"

Inhibitoren der Korrosion 27 (1). Inhibitoren der Korrosion von Kupfer - Gibt es eine Struktur-Wirkungsbeziehung?

1982

Mehr als 570 Verbindungen der unterschiedlichsten Struktur wurden unter Standardbedingungen im “Schuttelversuch” und pH-statisch auf ihre Korrosionsschutzwirkung gegenuber Kupfer getestet und mit Hilfe eines Computers ausgewertet. Die erhaltenen Ergebnisse stehen relativ haufig in Ubereinstimmung mit Dem “Hart-Weich-Konzept” von Pearson. Eine gezielte Synthese von Inhibitoren, die sich in diesem Konzept orientiert, ist jedoch nicht moglich. Inhibitors of corrosion 27 (1). Inhibitors of the corrosion of copper Does there exist a structure-effect-relation? Over 570 compounds of greatly varying structure have been tested under controlled conditions in agitation and pH-stat experiments designed…

Water Adsorption Properties of Free and Dehydrated β-Cyclodextrin Studied by near Infrared Spectroscopy and Gravimetry

2016

β-cyclodextrin, like other carbohydrates has a tendency to adsorb water molecules and the properties are attributed to the hydroxyl groups in the molecules. β-cyclodextrin, the cyclic oligomer of glucose has a hydrophobic interior and hydrophilic exterior. The cyclic structure favours the formation of hydrogen bonds between the OH groups on the adjacent glucose units and affects the formation of hydrogen bonds with water molecules. The hydoxyl groups engaged in hydrogen bondings can be eliminated at high temperatures and the adsorption properties of the dehydrated β-cyclodextrin will depend on the new functional groups formed. The aim of the report is to discuss the issue of the water adsor…

Strategies for Exploring Functions from Dynamic Combinatorial Libraries

2020

Solid State Joining of Thin Hybrid Sandwiches Made of Steel and Polymer: a Feasibility Study

2020

Abstract The growing demand for more environmentally friendly vehicles has led to an increased use of light materials in the transportation industry with the aim to reduce structural weight, fuel consumption, and gas emissions, thereby boosting cost-effectiveness and recyclable properties. Complex multi-material steel-based components would allow to improve mechanical properties and minimize weight even further. In particular, new sandwich materials made by steel outer skins and a polymeric internal layer seems very promising for obtaining mechanical performance and lightness at the same time. Unfortunately, traditional welding techniques, like arc welding, laser welding, and resistance spo…

Towards highly luminescent phenylene vinylene films

1996

Abstract Fluorescence and electronic absorption spectra, fluorescence decay curves and fluorescence quantum yields of a series of oligo (p-phenylene vinylenes) are investigated in solution, nanoaggregates and vapour-deposited or cast ultrathin films. The film constituting molecules are varied in chain length and modified by electron donating and withdrawing substituents and bulky alkyl spacers. PPP-MO calculations serve to rationalize the resulting spectral changes. In dilute solutions, fluorescence yields of the short oligomers with alkyl or oxyalkyl substituents approach the region of unity. The yields decrease with chain length, reaching a long-chain limit of ΦF=0.4–0.7. Introduction of …

Extraction of short peptides using supported liquid membranes

2002

Studies of extraction of short peptides using supported liquid membranes containing Aliquat 336 as a carrier are presented. The extractions are carried out from an aqueous donor phase with pH ≥ 10 to an acceptor phase containing salt. The mass transfer is driven by the gradient of salt concentration between these phases. The extraction efficiency is dependent on the composition of water phases, the type and concentration of counter-ion in the stagnant acceptor phase and the flow rate of the donor phase. Moreover, it is also influenced by the concentration and structure of the examined peptides.

Geometric and electronic structure of dithiapyranylidine: evolution upon oxidation

1993

Abstract We present a theoretical investigation of the modifications that successive oxidation induces on the geometric and electronic structures of the π-electron donor dithiapyranylidene. The lengthening of the double bonds and the shortening of the single bonds calculated as the molecular charge increases indicate a gain of aromaticity with oxidation. Both the geometricand the electronic structure of dithiapyranylidene show a clear evolution towards those of biphenyl as oxidation takes place.

Sulfide mineral identification using laser-induced plasma spectroscopy

2003

Sulfide minerals in rock samples were identified with laser-induced plasma spectroscopy (LIPS) in the near vacuum ultraviolet spectral region. Reference spectra of pyrite, pyrrhotite, chalcopyrite, sphalerite, barite, calcite and dolomite were applied to classification of minerals in sulfur-bearing drill core samples. On the basis of the results mineral distributions in the sample were estimated. The potential of the LIPS method for in situ analysis is discussed.

First tetrathiafulvalene (TTF) cation-radical salt containing the inorganic polyoxometalate β-[Mo8O26]4⊖

1993

Biocompatible polymeric micelles with polysorbate 80 for use in brain targeting.

2008

In this paper, the synthesis and characterization of novel amphiphilic graft copolymers based on an alpha,beta-poly(N-2-hydroxyethyl)-D, L-aspartamide (PHEA) backbone and D, L-polylactic acid (PLA) hydrophobic side chains are reported. These copolymers were obtained starting from PHEA-ethylenediamine (PHEA-EDA), which was functionalized with polysorbate 80 (PS(80)) and/or PLA in order to obtain the PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA samples, respectively. The degrees of derivatization, DD(PS80) and DD(PLA), of PHEA-EDA-PS80-PLA, calculated by (1)H-NMR, resulted in being 1.2 +/- 0.03 mol% and 0.54 +/- 0.05 mol%, respectively, while that of PHEA-EDA-PLA was found to be 0.60 +/- 0.05 mol%. S…