Steffen Henkel  Sascha Beutel 《化学，工程师，技术》2013,85(6):872-885

The most used measuring principles for the determination of the pH are of electrochemical and optical nature. As measuring system glass electrodes and indicator papers are known by every user. Beside this there are further measuring principles for special applications for example the pH determination in tissues, pastes or under extreme process conditions. Furthermore there are methods like NMR for pH‐measurement, which will always relegate to a niche existence because of their complex and expensive apparatus. This article gives an overview of the different available methods and discusses potential applications.  相似文献   

    

Genko Marinov Marinov  Atanaska Pavlova Marinova  Maria Milinova Milanova  Steffen Happel  Dimitar Veselinov Karaivanov  Dmitry Vladimirovich Filosofov 《溶剂提取与离子交换》2013,31(5):459-469

ABSTRACT

The distribution of some rare-earth elements (REE) on DN resin (TODGA loaded resin by Triskem international) was determined from different concentrations of two inorganic (HCl, HClO₄) and two organic acids (CH₃COOH, CCl₃COOH). The separation of Ac from REE is researched, as well as some separation possibilities of the elements within the REE. The determined distribution coefficients allows the prediction of the elution profiles of the researched elements. Using the obtained results in this work further applications can be considered.  相似文献   

    

Dipl.‐Ing. Philip Mülheims  Dipl.‐Ing. Stefan Marz  Dr.‐Ing. Steffen Peter Müller  Prof. Dr. Bettina Kraushaar‐Czarnetzki 《化学，工程师，技术》2011,83(3):286-294

Solid open‐cell sponges, often denoted as foams in literature, are promising packing materials for applications in process engineering. Their structural properties lead to low pressure drop and enhanced heat and mass transport as compared to conventional packed beds. Over the past years, the potential advantages of these new structures have been the topic in numerous investigations. However, only a few publications mention or take into consideration how the sponge packings are fitted into the respective apparatus. Using solid sponges as catalyst supports in the partial oxidation of o‐xylene, this present contribution demonstrates the impact of the fitting procedure of sponges on the resulting process behaviour such as conversion and heat transfer.  相似文献   

    

Marcus Schenkel  Steffen Marx  Ludolf Krontal 《Beton- und Stahlbetonbau》2009,104(11):782-789

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Gregor Schacht  Lukas Müller  Manfred Curbach  Steffen Marx 《Beton- und Stahlbetonbau》2013,108(9):592-602

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Sebastian Schneider  Daniela Vcker  Steffen Marx 《Beton- und Stahlbetonbau》2012,107(12):836-845

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Phosphor Alloyed Cr?Mn?Ni Austenitic As‐cast Stainless Steel with TRIP/TWIP Effect     

Andreas Jahn  Karl‐Philipp Steinhoff  Tobias Dubberstein  Peter Franke  Marco Weider  Steffen Wolf  Alexander Kovalev  Alexander Glage  Andreas Weiß  Wolfgang Schärfl  Klaus Eigenfeld  Lutz Krüger  Piotr R. Scheller 《国际钢铁研究》2014,85(3):477-485

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Christoph von der Haar  Steffen Marx  Guido Bolle 《Bautechnik》2014,91(2):107-113

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Steffen Engelhart  Harald Burghardt  Regine Neumann  Ulrich Ewers  Martin Exner  Michael H. Kramer 《Indoor air》1999,9(2):139-143

Abstract In the past two decades, a group of health problems related to the indoor environment – generally termed sick building syndrome (SBS) – has emerged. We present an investigation of SBS in employees of a ministry working in a naturally ventilated office building that formerly had been used by a pharmaceutical company. A preceding environmental monitoring had failed to identify the cause(s) for the complaints. We conducted a questionnaire-based investigation and categorized the building sections and rooms according to their renovation status and their former use, respectively. The highest level of complaints was found among the employees working in rooms that in the past had been used for the production or storage of various pharmaceutical products suggesting that pharmaceutical odors may be a risk factor for SBS. Clinical laboratory tests did not show any unusual results. We conclude that the former use of a building for production and storage of pharmaceutical products should be considered as a possible risk factor for complaints about indoor air quality, e.g., when advising about or planning for renovations of buildings formerly used for production, handling, or storing of chemicals.  相似文献   

    

Steffen Zimmermann  Cees S. Kleinman  Dirk A. Hordijk 《Beton- und Stahlbetonbau》2005,100(8):705-719

Microstructure‐Based Constitutive Relations for Cement‐Bonded Particle Composites In material research, homogenization methods distinguish themselves by defining effective material properties, which are representative of the heterogeneous material. After a brief note on recent developments in this field, first, the basics of homogenization are introduced and refined with respect to cement‐bonded particle‐reinforced composites. A geometry‐oriented idealization of the microstructure is proposed and closed‐form solutions of bulk and shear modulus derived. Based on these new definitions the effects of the leading micro‐scale parameters on effective linear‐elastic properties are discussed and conclusions drawn for modern concrete technology. A prospective view on the possibilities of homogenization to deal with nonlinear effective properties of composite materials concludes the paper.  相似文献