Charakterisierung von Glas und Glasbeschichtung mittels oberflächensensibler Sondenverfahren

The presented results of investigations by surface and microanalytical methods confirm the suitability of electron beam and scanning probe techniques for process monitoring, support of process development and defect analyses in the glass industry. More and more glass and coating specialists use the high tech service provided by an external laboratory with its wide range of experience and knowledge.     

Die Kalibrierung von Vakuummessgeräten in Industrie und Forschung

The increasing economic demand for higher measurement accuracy and the demands of modern quality assurance systems require regular calibration of the measuring and testing gauges. Vacuum gauges are more and more utilized as measuring and testing gauges in manufacturing processes and research in order to get reliable and correct product specifications. Systematic and statistical measuring deviations can only be determined through calibration. The reliability of test results is not only dependent on the accuracy, precision, repeatability and reproducibility but also depends on the competence of the tester and correctness of the testing method. Therefore, the confidence in the validity of the measurement results and in the competence of the calibration laboratory is a decisive factor. The calibration of vacuum gauges and the traceability to national standard is done through a series of comparison measurements. The calibration laboratories of the German calibration service (DKD), which are accredited by the Physikalische‐Technische Bundesanstalt (PTB), are distinguished by their technical expertise and high quality standard. The DKD‐calibration certificates offer reliable measurement results including the measuring uncertainty and are accepted by the accreditation bodies of the member states of the European co‐operation for Accreditation (EA). The typical requirements on a calibration laboratory for vacuum gauges are explained exemplarily for the DKD‐calibration laboratory of VACUUBRAND GMBH + CO KG company.     

Bedeutung der Unregelmäßigkeit Gauß'scher Zufallsfolgen für die Betriebsfestigkeit

Significance of Irregularity of Gaussian Random Sequences on Random Fatigue The results of investigations concerning the influence of the irregularity factor which are found in the literature are often contradicting. The cause may be, that with the variation of the irregularity factor in some cases other influencing parameters were unintentionally varied too. To help clarify the situation a test program was conducted. Notched specimen and single shear lap joints of the aluminium alloy 2024 were tested under axial random loading sequences to determine the influence of irregularity on fatigue life. The irregularity factors (l = 0,99, 0,7, 0,3) cover the range interesting in practice. The method to generate random sequences ensures that the factor of irregularity is the only variate among the usual parameters of the random sequence.