Small‐angle X‐ray scattering investigation of the deformation processes in the amorphous phase of high density polyethylene

In situ small‐angle X‐ray scattering of high density polyethylene under uni‐axial tensile test was used for investigating the deformation at the scale of the periodic crystalline–amorphous nano‐structure. The more or less uniform elastic straining of the rubbery amorphous layers is discussed in terms of mechanically active intercrystalline tie chains. Correlation is made with the long‐term use properties. It is concluded that this approach is a powerful means to assess the mechanical efficiency of tie molecules. Copyright © 2004 Society of Chemical Industry     

über die Fourier-Entwicklung der Felderregerkurve von dreiphasigen Durchmesser-Ganzlochwicklungen

Zusammenfassung Unter Benutzung der Fourier-Entwicklung eines Trapezes wird zunächst die Felderregerkurve einer Einphasen-Ganzlochwicklung mit g Nuten je Pol hergeleitet. Dabei wird linearer Anstieg der Treppenstufen über die Nutschlitzbreite angenommen. Hierauf wird die Felderregerkurve der Dreiphasen-Ganzlochwicklung mit Durchmesserspulen und g Nuten je Pol und Phase entwickelt. Durch Grenzübergänge gewinnt man aus dieser Darstellung die im Schrifttum angegebenen Sonderfälle. Die Güte der Näherung wird durch Benutzung der ersten vier Glieder der Entwicklung für zwei kennzeichnende Formen der Felderregerkurve durch Zeichnung gezeigt.     

Measurement of thermal conductivity of polymer melts by the line-source method

An apparatus has been developed for the measurement of thermal conductivity of polymer melts. Based on the transient “line source method,” it is ideally suited to these materials because measurements can be made quickly, before the onset of thermal degradation. Also, little or no sample preparation is required. A number of commercial polymers have been tested, including some glass-fiber filled composites.     

Heuristische Erlösprognosen für die Bewertung von Geschäftsmodellen im Application Service Providing

Several problems complicate the assessment of enterprises that cooperate with other firms in developing and distributing bundled goods. Revenue forecasts are particularly challenging. Cooperating suppliers must estimate and model future prices and sales volumes. They have to agree on a ratio of distribution for jointly generated revenues. Furthermore, they must compare different value chain configurations and assess consequences for the distribution of revenues. We propose a heuristic method that helps to forecast revenues for bundled goods. We demonstrate the heuristic method with the example of Application Service Providing.     

Microfluidic push-pull probe for scanning electrochemical microscopy

This paper presents a microfluidic push-pull probe for scanning electrochemical microscopy (SECM) consisting of a working microelectrode, an integrated counter/reference electrode and two microchannels for pushing and pulling an electrolyte solution to and away from a substrate. With such a configuration, a droplet of a permanently renewed redox mediator solution is maintained just at the probe tip to carry out SECM measurements on initially dry substrates or in microenvironments. For SECM imaging purposes, the probe fabricated in a soft polymer material is used in a contact regime. SECM images of various gold-on-glass samples demonstrate the proof-of-concept of a push-pull probe for local surface activity characterization with high spatial resolution even on vertically oriented substrates. Finite element computations were performed to guide the improvement of the probe sensitivity.     

Optimal confidence interval for the largest normal mean under heteroscedasticity

A two-stage sampling procedure for obtaining an optimal confidence interval for the largest or smallest mean of k independent normal populations is proposed, where the population variances are unknown and possibly unequal. The optimal confidence interval is obtained by maximizing the coverage probability with a fixed width at a least favorable configuration of means. Then, the sample sizes can be determined by this procedure. It has been shown that the optimal interval is globally optimal over all possible choices of symmetric and asymmetric intervals. In situations where the two-stage sampling procedure cannot be completely carried through, a one-stage sampling procedure can be implemented, and their relationship is discussed. A numerical example to demonstrate the use of these sampling procedures is given.     

Water-jet dissection in renal surgery: experimental study of a new device in the pig

The pig model was used for experiments with a new type of water-jet dissector, which produces high-pressure water by application of a gas and maintains the water fully sterile in a single-use delivery apparatus. The experiment was conducted ex vivo (14 kidneys) and in vivo to compare electric cautery section with water-jet dissection (5 vs 11 partial nephrectomies). Ex vivo study confirmed sparing of blood vessels and pelvicaliceal system. In vivo study did not show significant differences in blood loss but, the water-jet allowed precise dissection and tight closure of the excretory system. More frequent haemorrhages were noted on histological examination of the WJ group, but no coagulation necrosis. These are preliminary findings and further studies of long-term results may confirm the benefits of the absence of parenchymal necrosis and the definite advantage of precise closure of the pelvicaliceal system, as morbidity of partial nephrectomy is often related to secondary haemorrhages and urinary fistulae.