排序方式: 共有11条查询结果,搜索用时 31 毫秒
1.
Johanna Sohr Markus Schubert Steve Flechsig Eugeny Y. Kenig Uwe Hampel 《化学,工程师,技术》2019,91(1-2):139-144
Sandwich packings, consisting of alternatingly stacked conventional structured packings with different geometric surface areas, are promising for increasing capacity and efficiency of separation columns. Film flow and froth flow evolve along a stack, which requires comprehensive fluid dynamic analysis. In particular, the froth height is an essential parameter to determine the spatial extent of the flow regimes. Ultrafast X‐ray tomography and a 3D‐printed pressure drop profile measurement module were applied to independently estimate this parameter. The results are compared with existing correlations. 相似文献
2.
Steve Flechsig Torben Borgolte Yaroslav Utchenko Johanna Sohr Markus Schubert Uwe Hampel Eugeny Y. Kenig 《化学,工程师,技术》2019,91(1-2):125-138
The efficiency of columns for fluid separation can be increased by the application of sandwich packings. During the operation, different load‐dependent regimes with peculiar separation performance arise. In order to account for the effects of the individual flow regimes in a single model, both separation performance measurements and tomographic imaging are applied. A rate‐based model is presented, which takes the heterogeneous regimes in sandwich packings into account by means of appropriate correlations. The model is tested with experimental data for CO2 absorption. 相似文献
3.
Student nurses are often intimidated by the research process. They also frequently have negative attitudes about working with the elderly, especially in long-term care settings. This article describes a clinical project designed to help students improve their attitudes, knowledge, and skills toward research and care of the elderly by connecting the research process and the nursing process. Students implement research-based clinical practice in a long-term care setting. Student evaluations indicate that project goals are achieved. Nursing staff evaluation data indicate that they find student projects interesting and useful in updating resident care plans. 相似文献
4.
5.
A. Jung R. Zenker J. Gleißner K. Lerche T. Sohr J. Lerche 《Materialwissenschaft und Werkstofftechnik》2014,45(6):486-495
Stainless steel components exposed to mechanical stresses are subjected not only to corrosion, but to abrasive wear. There are several possibilities for enhancing the wear resistance of stainless steels; however, such processes are very often associated with a reduction in corrosion resistance. This paper presents an electron beam surface treatment technology to significantly improve the wear resistance of austenitic steels (e.g. X6CrNiMoTi17‐12‐2) and duplex steels (e.g. X2CrNiMoN22‐5‐3), without a negative influence on the corrosion behavior. Fe‐ and Co‐additive wires were deposited thermally by electron beam cladding. The cladding layers produced were free of defects such as cracks and pores, and were well metallurgical bonded to the base materials. Microstructural analysis, hardness measurements, wear tests and corrosion tests were carried out. The wear rate k was reduced by a factor of 100 compared to the base materials for electron beam cladding with Fe‐based wire and by a factor of 10 with Co‐based wire. Corrosion resistance was preserved for the Fe‐based cladding layers and slightly increased (by a factor of 3) for the Co‐based cladding layers. 相似文献
6.
Uwe Hampel Markus Schubert Alexander Döß Johanna Sohr Vineet Vishwakarma Jens-Uwe Repke Sören J. Gerke Hannes Leuner Matthias Rädle Viktoria Kapoustina Lucas Schmitt Marcus Grünewald Jost H. Brinkmann Dominik Plate Eugeny Y. Kenig Nicole Lutters Lukas Bolenz Felix Buckmann Dominique Toye Wolfgang Arlt Thomas Linder Rainer Hoffmann Harald Klein Sebastian Rehfeldt Thomas Winkler Hans-Jörg Bart Dominic Wirz Jonas Schulz Stephan Scholl Wolfgang Augustin Katharina Jasch Florian Schlüter Natalie Schwerdtfeger Stefan Jahnke Andreas Jupke Christoph Kabatnik Andreas Siegfried Braeuer Mirko D'Auria Thomas Runowski Maria Francisco Casal Karsten Becker Anna-Lena David Andrzej Górak Mirko Skiborowski Kai Groß Hina Qammar 《化学,工程师,技术》2020,92(7):926-948
Modelling flow and mass transfer of thermal separation equipment constitutes one of the most challenging tasks in fluids process engineering. The difficulty of this task comes from the multiscale multiphase flow phenomena in rather complex geometries. Both analysis of flow and mass transfer on different scales as well as validation of models and simulation results require advanced experimental and measurement techniques. As a follow-up to intensive discussions during the 2019 Tutzing Symposium “Separation Units 4.0” a wide set of available modern experimental technologies is presented. 相似文献
7.
Henk Birkholz Carsten Elfers Bernd Samjeske Karsten Sohr 《Datenschutz und Datensicherheit - DuD》2011,35(4):258-261
Koordinierte verteilte Angriffe im Internet sind ein akutes Problem. W?hrend Angriffe jedoch in kollaborativen Verbünden organisiert
werden, verteidigen Unternehmen sich h?ufig im Alleingang. Sicherheitsma?nahmen gelten oft als wohl gehütete Geheimnisse und
werden ungern preisgegeben. In diesem Beitrag werden Methoden und Voraussetzungen vorgestellt, die einen kooperativen Austausch
von sicherheitsrelevantem Wissen erm?glichen, ohne damit etwaige eigene Schwachstellen offen zu legen. 相似文献
8.
About 8600 complete or nearly complete sequences are now available from the Antwerp database on small ribosomal subunit RNA. All these sequences are aligned with one another on the basis of the adopted secondary structure model, which is corroborated by the observation of compensating substitutions in the alignment. Literature references, accession numbers and detailed taxonomic information are also compiled. The database can be consulted via the World Wide Web at URL http://rrna.uia.ac.be/ssu/ 相似文献
9.
Sohr K. Drouineaud M. Ahn G.-J. Gogolla M. 《Knowledge and Data Engineering, IEEE Transactions on》2008,20(7):924-939
Today more and more security-relevant data is stored on computer systems; security-critical business processes are mapped to their digital counterparts. This situation applies to various domains such as health care industry, digital government, and financial service institutes requiring that different security requirements must be fulfilled. Authorisation constraints can help the policy architect design and express higher-level organisational rules. Although the importance of authorisation constraints has been addressed in the literature, there does not exist a systematic way to verify and validate authorisation constraints. In this paper, we specify both non-temporal and history-based authorisation constraints in the Object Constraint Language (OCL) and first-order linear temporal logic (LTL). Based upon these specifications, we attempt to formally verify role-based access control policies with the help of a theorem prover and to validate policies with the USE system, a validation tool for OCL constraints. We also describe an authorisation engine, which supports the enforcement of authorisation constraints. 相似文献
10.