Merseburg University of Applied Sciences
Merseburg, Germany

The Merseburg University of Applied science - University of Applied science) is a higher education institution located in the town of Merseburg, Germany. It was established on April 1, 1992. Its precursor was the Technical University Leuna-Merseburg . Wikipedia.

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Linde B.B.J.,University of Gdask | Rosenfeld E.,Merseburg University of Applied Sciences
Journal of the Acoustical Society of America | Year: 2011

Similarities and differences in vibrational behavior of two guitars having a symmetric Torres bracing pattern and an asymmetric pattern forming a lattice on a soundboard are investigated by means of the modal analysis technique and laser Doppler vibrometry (LDV) measurements. Instruments are investigated before and after a bridge and strings assembling (i.e., they are incomplete or complete). The bracing pattern and the absence/presence of the bridge and strings have some effect on modal frequencies and mode shapes. The bracing pattern does not affect the sequence of at least first three low frequency mode shapes of incomplete/complete instruments but affects their modal frequencies. Depending on frequency, the bridge behaves either as a rigid or a flexible structure. © 2011 Acoustical Society of America.

The pressure in the impeller, in the side channel and in the breaker of a side channel compressor with the polytropic compression and with the polytropic expansion of the breaker mass flow was investigated experimentally, and the occurring shock waves were detected during the expansion of the gas in the breaker. Thereby different pressure flows occur at the four measuring points in blade channel on the blade pressure and suction side of the related radius from ri/r2 = 0.80 and ri/r2 = 0.95, which give an indication of the blade channel flow. In addition to the periodic increase in pressure and the gas expansion in the breaker, the superimposed pressure oscillation in the side channel is caused by the blade rotation frequency. This superimposed pressure oscillation can be decomposed by Fourier transformation in the two pressure oscillation components. These phenomena are the reason for the more accurate investigation of the pressure flow in the blade channel during the polytropic compression and expansion of the breaker mass flow. The gradient of the effective values of the gas pressure oscillation in the blade channel leads not only to the operating characteristics of the side channel compressor Δp = f(φ, n), but also to the breaker curve characteristic ΔpU = f(φ, n). © Springer-Verlag 2011.

Jenderka K.-V.,Physikalisch - Technische Bundesanstalt | Jenderka K.-V.,Merseburg University of Applied Sciences | Wilkens V.,Physikalisch - Technische Bundesanstalt
Metrologia | Year: 2012

The reliable description of the ultrasonic fields of high-intensity therapeutic ultrasound (HITU) devices is a prerequisite concerning the safe application of the method in the daily clinical routine. Since ultrasonic sensors used for the characterization of diagnostic fields are at high risk of being damaged in the strong therapeutic fields, the measurements are carried out in burst mode to reduce the acting temporal-average intensities. For the thorough investigation of possible differences between the excitation in continuous wave (cw) and burst mode, the temporal-average total acoustic output powers of two types of HITU transducers with f-numbers of approximately 1 and with working frequencies between 1.1MHz and 3.3MHz were investigated by means of a radiation force balance. The maximum cw equivalent power level was 300W; the duty cycles varied between 1% and 90%. In addition, the possible effect of the transducer-target distance was investigated. It was found that the different turn-on and turn-off behaviour of the transducers caused variations of the effective duty cycle, depending on the power level and the power amplifier used. The temporal-average power declined with increasing distance as expected, and no focal anomaly was detected. © 2012 BIPM & IOP Publishing Ltd.

Androsch R.,Martin Luther University of Halle Wittenberg | Hohlfeld R.,Merseburg University of Applied Sciences | Frank W.,Merseburg University of Applied Sciences | Nase M.,Orbita Film GmbH | Cavallo D.,TU Eindhoven
Polymer (United Kingdom) | Year: 2013

The kinetics of crystallization of isotactic polybutene-1 has been investigated as a function of the concentration of propylene chain defects between 0 and 20 mol% by temperature/time-resolved wide-angle X-ray scattering during slow cooling of the melt followed by annealing at ambient temperature. Slow cooling of the melt of the homopolymer leads to formation of Form II mesophase which then transforms on isothermal annealing at ambient temperature to Form I crystals within a period of 10-20 days. Presence of propylene co-units/chain defects in polybutene-1 leads to a retardation of Form II mesophase formation on cooling and simultaneously an acceleration of the mesophase-crystal phase transformation. In random butene-1/propylene copolymers containing about 7 mol% propylene crystallization is completed in less than a day. For copolymers with more than 7 mol% propylene, Form I crystals develop by both reorganization of Form II mesophase and directly from the melt. The study is completed by evaluation of the effect of copolymerization on the crystallinity and crystal perfection. © 2013 Elsevier Ltd. All rights reserved.

Koch C.,Merseburg University of Applied Sciences | Jenderka K.-V.,Merseburg University of Applied Sciences
Metrologia | Year: 2014

The CCAUV.U-K3 is the third key comparison in the ultrasound branch organized under the auspices of the Consultative Committee for Acoustics, Ultrasound and Vibration (CCAUV) of the BIPM. The goal of the key comparison was to show the capabilities of laboratories to determine the acoustic radiation conductance of an ultrasonic transducer by measuring the total time-averaged ultrasonic power emitted for an applied rms-voltage. Although the ultrasound power is the measurand of the key comparison the participants were asked to report the radiation conductance which is independent of the applied voltage and is therefore a characteristic property of the transducer at a particular frequency. One transducer was circulated during the comparison and after every two participants a remeasurement was carried out by the pilot laboratory. A total of 10 sets of measurements were made, including measurements at the start and end of the comparison and additional measurements after the repair. Because of significant discrepancies within the data a special method for finding the largest consistent subset of participants had to be applied. The procedure was robust and provided reasonable results to exclude statistically inconsistent data from the tabulated degrees of equivalence.

Rosenfeld E.,Merseburg University of Applied Sciences | Jenderka K.-V.,Merseburg University of Applied Sciences | Kopp A.,Merseburg University of Applied Sciences | Keim V.,University of Leipzig
Ultraschall in der Medizin | Year: 2013

This article deals with the technical quality assurance of ultrasound B-systems. As part of a mini-trial during the Dreiländertreffen in Davos "Ultrasound 2012o", we addressed the question as to whether physicians can detect faulty probes spontaneously during live scanning B-mode. For this purpose a special diagnostic device had been prepared so that groups of piezoelectric elements in the array were without function. Then the images had to be characterized by test persons without knowledge of the faulty elements. The results show that a deterioration of the image could be detected starting at five disabled elements. Due to the small number of test persons, our statements are only preliminary. © Georg Thieme Verlag KG Stuttgart · New York.

Ulrich J.,Harzklinikum Dorothea Christiane Erxleben | Schwurzer- Voit M.,Hautarztpraxis Hemau | Jenderka K.-V.,Merseburg University of Applied Sciences | Voit C.,Charité - Medical University of Berlin
JDDG - Journal of the German Society of Dermatology | Year: 2014

Ultrasonography non-invasively visualizes changes within the skin, skin appendages, subcutaneous tissue, subcutaneous (regional) lymph nodes and peripheral vessels. Thus it is an established diagnostic tool in dermatology. Compared to X-ray, MRI and PET, ultrasonography has some advantages; however, it is more dependent on the individual experience of the investigator. Therefore a structured education and continuous training are necessary. This review describes the physical and technical basics, the administrative requirements and the main indications in dermatology. © 2014 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

Ringeisen T.,Merseburg University of Applied Sciences | Raufelder D.,Free University of Berlin
Journal of Adolescence | Year: 2015

This study examined gender-specific relationships between adolescents' perceptions of school-related support/pressure from their parents and test anxiety. A sample of German students (N = 845; Mage = 15.32; SD = .49) completed questionnaires that measured their perceived parental support/pressure (for mother and father separately) as well as the four main components of test anxiety (worry, interference, lack of confidence, and emotionality). Gender-specific relations were identified using multigroup structural equation modeling: For girls, perceived maternal pressure was positively associated with emotionality and interference; for boys, perceived father pressure and father support were positively associated with interference and worry, respectively. For both genders, perceived mother pressure and support were related to lack of confidence. Our findings suggest that adolescents' perceptions of maternal attitudes are associated with students' self-confidence irrespective of the child's gender, whereas the remaining facets of test anxiety follow same-sex trajectories between perceived parental attitudes and adolescents' test anxiety. © 2015 The Foundation for Professionals in Services for Adolescents.

Sonography is based on multiple interactions between ultrasonic waves and the tissue during propagation. Therefore, ultrasound images contain more information than the mere visualization of the anatomic structures. Assessing the different echogenicity and texture of tissue regions yields additional information about the pathologic tissue alterations. Precise interpretation requires knowledge of the whole process of image generation. This also applies for the adjustment of system parameters for image improvement. This article explains the phenomena of ultrasound propagation in tissue and the principles of ultrasound image generation-from the scan head to the image on the screen. © 2013 Springer-Verlag Berlin Heidelberg.

Lange T.,Merseburg University of Applied Sciences | Mozharovskyi P.,University of Cologne
Studies in Classification, Data Analysis, and Knowledge Organization | Year: 2014

A procedure, called α-procedure, for the efficient automatic classification of multivariate data is described. It is based on a geometric representation of two learning classes in a proper multi-dimensional rectifying feature space and the stepwise construction of a separating hyperplane in that space. The dimension of the space, i.e. the number of features that is necessary for a successful classification, is determined step by step using two-dimensional repères (linear subspaces). In each step a repère and a feature are constructed in a way that they yield maximum discriminating power. Throughout the procedure the invariant, which is the object’s affiliation with a class, is preserved. © Springer International Publishing Switzerland 2014.

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