Comparison of <i>S</i>-Parameter Measurement Methods for Adapters

In this work two methods for the characterization of adapters meaning reciprocal two-ports with different connector styles on both ports are analyzed and compared in detail. The focus is on the comparison of these approaches in terms of required effort and obtained measurement uncertainty. The first method is based on two one-port calibrations and it is compared to a two-port approach. Both methods are carried out in simulation as well as in measurement under very comparable conditions using a 2.4 to 3.5 mm adapter in the frequency range up to 33 GHz as an example. The obtained measurement uncertainties of the results are presented and analyzed, the required measurement time in terms of the necessary number of separate connections is compared, and the influence of cable movements is discussed.</p

The RASPUTINE pilot study - A prospective randomised controlled evaluation of two stabilisation procedures for incomplete cranial burst fractures of the thoracolumbar junction

F. H. Greenhill's preserved Burrell steam tractor No.3603, registration 'CL4295'(built 1914). 'F. H. Greenhill Agricultural Contractor' on canopy. Image taken at a steam rally, circa 1965

Spray formation of middle distillates for autothermal reforming

The reforming of diesel and diesel-like fuels plays a central role in the development of fuel cell systems for on-board power supplies. The vaporization of the fuel via a spray formation and the subsequent mixture with water vapor and air determine the quality of the reforming process, as is shown in this paper. By using a high quality nozzle residual hydrocarbons were below 25 ppmV during the reforming of standard diesel. Through the use of a fuel injector in pulsed operation, the load range was able to be increased from 1:1.67 to 1:6. Spray pattern analyses were conducted using a high-speed camera. The formation of the spray pattern lasted 1.5–2 ms. The testing of a fast-closing magnetic valve manufactured by GSR Ventiltechnik was carried out on the autothermal reformer (ATR) type AH2. It exist not any direct influence of the pulsed operation on hydrogen production

Isomerizing Olefin Metathesis as a Strategy To Access Defined Distributions of Unsaturated Compounds from Fatty Acids

The dimeric palladium­(I) complex [Pd­(μ-Br)^tBu₃P]₂ was found to possess unique activity for the catalytic double-bond migration within unsaturated compounds. This isomerization catalyst is fully compatible with state-of-the-art olefin metathesis catalysts. In the presence of bifunctional catalyst systems consisting of [Pd­(μ-Br)^tBu₃P]₂ and NHC–indylidene ruthenium complexes, unsaturated compounds are continuously converted into equilibrium mixtures of double-bond isomers, which concurrently undergo catalytic olefin metathesis. Using such highly active catalyst systems, the isomerizing olefin metathesis becomes an efficient way to access defined distributions of unsaturated compounds from olefinic substrates. Computational models were designed to predict the outcome of such reactions. The synthetic utility of isomerizing metatheses is demonstrated by various new applications. Thus, the isomerizing self-metathesis of oleic and other fatty acids and esters provides olefins along with unsaturated mono- and dicarboxylates in distributions with adjustable widths. The cross-metathesis of two olefins with different chain lengths leads to regular distributions with a mean chain length that depends on the chain length of both starting materials and their ratio. The cross-metathesis of oleic acid with ethylene serves to access olefin blends with mean chain lengths below 18 carbons, while its analogous reaction with hex-3-enedioic acid gives unsaturated dicarboxylic acids with adjustable mean chain lengths as major products. Overall, the concept of isomerizing metatheses promises to open up new synthetic opportunities for the incorporation of oleochemicals as renewable feedstocks into the chemical value chain