Characterization of Palladium Nanoparticles Adsorpt on Polyacrylic Acid Particles as Hydrogenation Catalyst

Palladium particles can be prepared in sizes of a few nanometers from Pd(OAc)₂in the presence of a block copolymer in aromatic unpolar solvents with suitable reducing agents like NaBH₄ or LiAlH₄. After mixing the organic metal solution with a polyacrylic acid (PAA) dispersion of defined concentration and following a crosslinking process with an epoxide, reactive membranes with a well-defined pore diameter were obtained. The catalytic activity of the prepared palladium particles incorporated in the crosslinked PAA network has been proven by the gas phase hydrogenation of propyne in a special membrane reactor.     

Effect of roasting on the radical scavenging activity of cocoa beans

The free-radical scavenging activity of cocoa samples subjected to different roasting treatments has been determined. The samples (raw, pre-roasted and roasted) were separated into four molecular weight fractions per sample (>30, 30–10, 10–5, and <5 kDa). The free-radical scavenging activity was determined with the DPPH^• (1,1-dipheny-2-picrylhydrazyl), and ABTS^•+ [2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)] free-radical scavenging assays for all samples. Both tests were compared in terms of sensitivity and measurement precision, at different reaction times. Comparing the results from each test, the free-radical scavenging activity trends were similar for each fraction but with notable differences in the sensitivity of the assays. Analysis of the concentration of reducing substances, such as water soluble phenolics, melanoidins, carbohydrates, etc, in these fractions by the photometric Folin–Ciocalteu assay, showed a similar pattern to the free-radical scavenging activity trend. Moreover, this comparison showed that there were significantly (P < 0.05) more reducing substances and free-radical scavenging activity in the 10–5 kDa roasted cocoa bean fraction.     

Diagnosis and therapy of lymphoid tumors of the orbits

Injuries of the laryngotracheal axis caused by prolonged intubation in critically ill patients raise the issue of the timing of tracheotomy in intubated patients. In 1992 a prospective study was begun in intensive care patients with intubation lasting more than 48 hours. Eight months later, post-mortem data on the laryngotracheal axis of deceased patients was added to our prospective study protocol. The study was closed with 125 cases (52 deceased). The clinical data of 73 surviving patients was compared with that of 18 post-mortem cases. The macroscopic results of the post-mortem study are summarized by grading the lesions according to a personal modification of the Lindholm classification. All cases had laryngotracheal injuries. Only 15% of the lesions were located in the tracheal region. Five cases were classified as grade 2, with an average orotracheal intubation of 9 days, 9 cases as grade 3 with 15 days intubation, and 4 cases as grade 4 with 21 days intubation. We concluded that the severity of laryngotracheal injuries in the early post-mortem exploration was related with the duration of intubation.     

The role of the concept of "history of safe use" in the safety assessment of novel foods and novel food ingredients. Opinion of the Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG)

The Council of the European Union has proposed a revision on the EU regulation on novel foods and novel food ingredients concerning safety assessment of traditional foods from non-EU countries and their introduction onto the EU market. The proposal stipulates that such foods may be placed on the EU market if their history of safe use in the country of origin is appropriately documented. The present statement of the SKLM gives an overview on current discussions on practical implementation of the "history of safe use" concept as well as examples of its application. The SKLM, in principle, agrees with these concepts, underscores, however, in connection with convincing evidence for a "history of safe use" the need for a range of additional information to achieve a comprehensive risk assessment. In the opinion of the SKLM such information must comprise compositional data as well as experience on adverse effects. A list of questions considered essential is presented. The following opinion was adopted on December 23rd 2010.     

H. F.-Bias gesputterte TiN-Schichten zur Verschleißminderung an Grauguß-Kolbenringen

RF-Bias Sputtered TiN-Coatings to Reduce Wear of Cast-Iron Piston Rings By means of the reactive r.f. magnetron sputtering process TiN coatings with a thickness of 2.5 m?m and 6 m?m respectively, have been deposited onto piston rings made of cast iron. The coated piston rings have been tribologically tested using a model wear test, the so called short stroke test, which allows simultaneous testing of eight rings. This test method involves the most important stress features of the fired motor so that a good simulation of the stress conditions under which the piston rings and cylinder linings are working, is achieved. The results found with the short stroke test are compareable to those found with a fired test motor. The test was performed using TiN coated, uncoated and hardchromium electroplated cast iron rings. The reduction of the total wear of the rings and cylinder linings using a 6 m?m thick TiN coating was 85° compared to the uncoated rings and 50° compared to the chromium coated rings. The adhesion of the TiN coatings is excellent and even the graphite inclusions on the cast iron surface did not lead to any adhesion failure of the coatings under the present stress conditions.     

Digitale Bildverarbeitung spannungsoptischer Isochromatenbilder

Digitale Bildanalysesysteme bieten die Möglichkeit, Verfahren der Bildverarbeitung wirkungsvoll auch in der Spannungsoptik einzusetzen. Es wird über die Bearbeitung, insbesondere über die Filterung von spannungsoptischen Isochromatenbildern berichtet, und zwar über die Hochpaßfilterung mit anschließender Konturverstärkung, über die Gradientenfilterung mit einem Sobel-Operator und über die Skelettierung. Als Beispiel dient ein I-Träger mit nebeneinanderliegenden, ovalen Löchern unter Querkraftbelastung. Es werden Schubspannungsverteilungen für die verschiedenen Bearbeitungsmethoden dargestellt.     

Creep equations for high temperature alloys on the basis of a parametric assessment of multi-heat data

For the design of high temperature components creep equations are necessary. These describe the deformation behaviour of the material type used over its whole application range. The method of developing such an equation is demonstrated for the example of alloy G-NiCo 15 Cr 10 Al 6 TiMo (Alloy 100). As a basic requirement, a multi-heat assessment of time to specific strain is performed with the aid of a time temperature parameter procedure. In this way optimum correlated master curves are generated for the whole range of permanent strain and rupture. From these curves mean creep curves for the material type can be determined by minimal further smoothing. On the basis of these creep curves a modified Garofalo equation with initial plastic strain as well as primary, secondary and tertiary strain can be established to describe the creep behaviour of Alloy 100. Additionally, an equation for the time temperature dependent contraction of this alloy can be developed. These equations form a useful tool for the calculation of high temperature components with the finite element method.     

Linear mappings ofn-dimensional uniform recurrences ontok-dimensional systolic arrays

We propose two methods for the synthesis of systolic arrays from uniform recurrence equations. First, we discuss a synthesis method for mappingn-dimensional uniform recurrence equations ontok-dimensional systolic arrays with a two-dimensional system clock. In this method we are led by the idea that all space-time conflicts caused by a scalar valued causal timing function and an allocation function can be rule out by a second scalar valued timing function. Stacking both timing functions yields a two-dimensional clock. Second, we develop a method to synthesizek-dimensional arrays with a scalar valued clock from a large subclass ofn-dimensional uniform recurrence equations containing important algorithms from signal and image processing. This method is based on a decomposition of the domain of the uniform recurrence equations into subdomains according to a given procesor allocation which allows the construction of a timing function for the whole domain from timing functions for the subdomains. In this way, the problem of finding optimal timing functions is reduced to finding optimal functions for the subdomains which are usually easier to establish. This synthesis method exhibits simplicity but its drawback lies in its limited applicability.