TY - CONF A1 - Klobes, Peter T1 - Zur Problematik der Darstellung von Porengrößenverteilungen und Aktivitäten zu ihrer Verankerung in nationalen und internationalen Normen N2 - Bei Untersuchungen der Porosität von Festkörpern - insbesondere mit Adsorptionsmethoden oder mit der Quecksilberporosimetrie - wird angestrebt, als wesentliche Aussage zur Charakterisierung eines porösen Stoffes Angaben über die mittlere Porengröße und über die Porengrößenverteilung zu erhalten. Während andere Kenngrößen poröser Materialien wie z. B. Porosität, spezifisches Porenvolumen oder spezifische Oberfläche eindeutig definiert sind, wird die Darstellung der Porengrößenverteilung trotz einer seit 1994 existierenden IUPAC-Empfehlung zur Zeit noch sehr uneinheitlich gehandhabt. Gleiches gilt auch für die verwendete Symbolik (Formel- und Kurzzeichen). Dies beeinträchtigt in der Praxis sehr häufig die Vergleichbarkeit, Übertragbarkeit und Interpretation der in unterschiedlichen Publikationen angegebenen Resultate. Eine einheitliche Darstellung von Porengrößenverteilungen wird zusätzlich noch dadurch erschwert, dass es keine einfache Definition der Größe einer einzelnen Pore gibt. Nur im Falle bildgebender Verfahren, welche einzelne Poren sichtbar machen können, ist ein direktes Ausmessen der Porengröße möglich. Alle anderen Verfahren leiten die Aussagen über Porengrößen und -verteilungen indirekt aus anderen gemessenen Kenngrößen ab, wobei neben der Erfassung unterschiedlicher physikalischer Größen durch verschiedene Messverfahren insbesondere die reale Porenform, die nur in Sonderfällen mit klaren geometrischen Modellen wie Zylindern, Kugeln oder parallelen Platten beschreibbar ist, eine entscheidende Rolle spielt. Im Vortrag wird auf die wichtigsten der bisher gebräuchlichen Darstellungsarten von Porengrößenverteilungen, ihren Informationsgehalt und ihre Beziehungen zueinander sowie auf Vor- und Nachteile einzelner Varianten eingegangen. Einen wesentlichen Beitrag zur angestrebten größeren Klarheit und Einheitlichkeit auf diesem Gebiet kann die Verankerung der Problematik in nationalen bzw. internationalen Normen leisten, die bislang aber noch in den Anfängen steckt. Über entsprechende Vorhaben im DIN-Arbeitsausschuss 11.42.08 "Partikelmesstechnik, Oberflächenmessverfahren" sowie in der WG3 des ISO/TC24/SC4 "Sizing by Methods other than Sieving / Pore Size Distribution, Porosity" wird berichtet. T2 - XII. Workshop über die Charakterisierung von feinteiligen und porösen Festkörpern CY - Bad Soden, Germany DA - 2004-11-16 PY - 2004 AN - OPUS4-5325 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter A1 - Minor, D.B. T1 - Development of the Porosimetry Standard NIST SRM 1917 / CRM BAM-P127: First Joint Reference Material Certification by NIST and BAM N2 - After a two years' work on the basis of the "Agreement on a Cooperation in the Field of Reference Materials" between NIST and BAM the first joint certification project of NIST and BAM could be successfully finished in August 2002. The material officially named NIST SRM 1917 / CRM BAM-P127 (pellets of Al2O3 with a diameter of about 1 mm) is a certified nanoporous reference material for mercury porosimetry ("Mercury Porosimetry Standard"). Similar to the BAM materials CRM BAM-PM-120, ?121 and -122, the whole Hg intrusion curve has been certified also for the present reference material. From this a number of advantages for the user result: · availability of a large number of certified data points in the typical working range of mercury porosimeters (0.1 to 400 MPa) · therefore the possibility of a wide range assessment of the pressure transducer performance and the volume calibration of the porosimeter · suitability of this reference material for 200 MPa instruments as well as for 400 MPa instruments 17 laboratories from the USA and 15 laboratories from European countries took part in the interlaboratory comparison. The statistical evaluation (calculation of the mean intrusion curve with uncertainty boundaries) has been carried out at NIST using the Vangel Rukhin algorithm. In particular, the certified properties are a) the Hg intrusion curve between 0.1 and 400 MPa b) the cumulative pore volume curve between 3.7 and 14708 nm c) the pore volume at selected intrusion pressures (as single values) as well as the mean and the most frequent pore diameter. This first joint development and certification of a reference material represents a new way in the collaboration between NIST and BAM, which make to avoid multiple developments at the international scale and therefore to save time, costs and expenses. T2 - Campuswoche der Humboldt Universität zu Berlin, Erwin-Schrödinger-Zentrum in Adlershof CY - Berlin, Germany DA - 2003-12-01 PY - 2003 AN - OPUS4-5327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hellmuth, K.-H. A1 - Klobes, Peter A1 - Meyer, Klaus A1 - Röhl-Kuhn, Barbara A1 - Siitari-Kauppi, M. A1 - Hartikainen, K. A1 - Hartikainen, J. A1 - Timonen, J. T1 - Matrix retardation studies: size and structure of the accessable pore space in fresh and altered crystalline rock N2 - For the assessment of the barrier function of the geosphere around a nuclear waste repository information about the nature of the accessible rock pore space and internal surfaces is needed. Intact samples of various types of fresh and altered crystalline rocks have been studied by means of mercury intrusion porosimetry and gas adsorption methods using various adsorbates. Furthermore, fluorescence microscopy and scanning electron microscopy was applied and the results were compared with those of impregnation with carbon-l4-polymethylmethacrylate (PMMA). Additional structural information was derived from hydraulic conductivity determinations using helium gas. The investigations were focussed on the reliability of these measurements of intact core samples, the influence of rock composition, structure and geological evolution on the microstructure of the matrices and the consequences regarding the retardation properties of the bedrock. PY - 1995 SN - 0303-4534 VL - 23 IS - 5/6 SP - 691 EP - 706 PB - Verl. für Geowissenschaften Wutzke CY - Berlin AN - OPUS4-11979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hellmuth, K.-H. A1 - Siitari-Kauppi, M. A1 - Klobes, Peter A1 - Meyer, Klaus A1 - Goebbels, Jürgen T1 - Imaging and Analyzing Rock Porosity by Autoradiography and Hg-porosimetry/X-ray Computertomography-Applications N2 - The application of two sets of methods for the characterization of rock pore systems is reported. Both are discussed in the context of other techniques described in the literature. (i) Impregnation with labelled polymethylmethacrylate (PMMA) and autoradiography or direct measurement of the tracer activity allows the investigation of the pattern of the spatial porosity distribution and quantitative measurement of mineral-specific, local porosities, porosity gradients as well as an assessment of hydraulic and diffusive transport properties. (ii) Quantitative information on surface areas within certain pore size ranges can be achieved by combination of mercury intrusion porosimetry with X-ray absorption computertomography. As examples of applications of these techniques, the effects of weathering, alteration, mechanical stress and large diameter coring on the pore network of rocks have been studied. PY - 1999 SN - 1464-1895 VL - 24 IS - 7 SP - 569 EP - 573 PB - Pergamon CY - Oxford AN - OPUS4-11980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, Klaus A1 - Klobes, Peter A1 - Röhl-Kuhn, Barbara T1 - Certification of reference material with special emphasis on porous solids N2 - Certified reference materials (CMRs) are very important for the reliability of the results of chemical analyses and, at the same time, constitute the basis of comparability of analytical data. The development of a new CRM is demonstrated using the example of porous and finely dispersed solids having specific surface area, specific pore volume, pore volume distribution, and mean pore radius as their characteristic values. Many of the properties of reference materials to be certified, such as their elemental content, are established by means of measurement procedures relying on different and independent principles of measurement. With porous or finely dispersed solids, however, the characteristic values referring to pores strongly depend on the size of the probe molecules used, a fact which is due to the fractal character of these substrates. This is particularly true for the specific surface area or the pore volume. As a result, when applying the method of gas adsorption, the certified values refer to a specified probe gas, e.g. to nitrogen. The use of other gases yields different numerical values for the characteristic values to be certified. Generally, the pore system of a solid contains pores of irregular shape. Therefore, depending on the presence of e.g. cylinder or slit pores, different evaluation models must be applied. For the verification of model calculation of microporous solids, zeolites with their crystallographically defined voids are particularly well suited. They can serve as a reference point for the correctness of the model used. PY - 1997 SN - 0023-4753 SN - 1521-4079 SN - 0232-1300 VL - 32 IS - 1 SP - 175 EP - 185 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-11981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klobes, Peter A1 - Röhl-Kuhn, Barbara A1 - Meyer, Klaus T1 - Zertifizierung von Referenzmaterialien am Beispiel poröser hochdisperser Feststoffe für die Methode der Gasadsorption N2 - Entsprechend den BCR Guidelines für die Herstellung von zertifizierten Referenzmaterialien (CRMs) und den ISO Guides 30-35 wurden CRMs mit den Kenngrößen spezifische Oberfläche, spezifisches Porenvolumen und Porenradius hergestellt. Als Methode wurde die Gasadsorption verwendet. Die Zertifizierungsanalyse und die Referenzmaterialien selbst werden beschrieben. KW - Zertifizierte Referenzmaterialien KW - Gasadsorption KW - Spezifische Oberfläche KW - Spezifisches Porenvolumen KW - Porenradius KW - Poröse Materialien KW - Disperse Feststoffe KW - Certified reference materials KW - Gas adsorption KW - Specific surface area KW - Specific pore volume KW - Pore radius KW - Porous materials KW - Dispersed solids PY - 1998 SN - 0016-3538 VL - 42 SP - 214 EP - 217 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-11982 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klobes, Peter A1 - Riesemeier, Heinrich A1 - Meyer, Klaus A1 - Goebbels, Jürgen A1 - Hellmuth, k.-H. T1 - Rock porosity determination by combination of X-ray computerized tomography with mercury porosimetry N2 - Abstract First results are described of coupling of mercury porosimetry with X-ray computerized tomography (CT) as a new combination technique for rock porosity studies. This technique is suitable for rock samples with a pronounced mercury intrusion-extrusion hysteresis and includes CT measurements before and after mercury intrusion. The entrapped portion of mercury, when the pressure after the intrusion into the rock sample is reduced to 0.1 MPa, serves as a contrast agent in the porous network to localize spatial distribution of rock porosity by CT. The results obtained show that the mercury intrusion and therefore the porosity were quite different for the separate mineral phases. Therefore the combination of mercury porosimetry and computer tomography can give 3-D data on mineral-specific porosity distributions with additional pore size information. In contrast to mercury porosimetry as a single method, results of the combination technique with CT represent a direct visualization of porosity variation and do not depend on any special pore network model. PY - 1997 SN - 0937-0633 VL - 357 IS - 5 SP - 543 EP - 547 PB - Springer CY - Berlin AN - OPUS4-11970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Klobes, Peter A1 - Riesemeier, Heinrich A1 - Meyer, Klaus A1 - Goebbels, Jürgen A1 - Siitari-Kauppi, M. A1 - Hellmuth, K.-H. ED - Gray, W. T1 - Investigation of rock samples using x-ray-microcomputer-tomography before and after mercury intrusion porosimetry N2 - A new method for the physical characterization of rock matrices for use in site investigations of nuclear waste repositories has been developed. The method can provide information needed in the assessment of the performance of the geosphere working as a natural barrier retarding the migration of radionuclides by diffusion into the rock matrix. Most conventional methods for the physical characterization of rocks give only bulk information. The combination of mercury porosimetry and computer tomography can give 3-D data on mineral-specific porosity distributions with additional pore size information. Additionally, limits for mineral-specific internal surface areas can be estimated, which is essential for the assessment of water-rock interaction and reactive interaction with radionuclides (sorption). Results of measurements on granitic rock (granodiorite) from the Baltic shield are discussed and integrated with results by complementary methods. T2 - 20th Materials Research Society Symposium on the Scientific Basis for Nuclear Waste Management CY - Boston, MA, USA DA - 1996-12-02 PY - 1997 SN - 1-558-99369-X SN - 0272-9172 N1 - Serientitel: Materials Research Society symposium proceedings – Series title: Materials Research Society symposium proceedings IS - 465 SP - 863 EP - 870 PB - Materials Research Society CY - Pittsburgh, Pa. AN - OPUS4-11971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harbich, Karl-Wolfram A1 - Klobes, Peter A1 - Hentschel, Manfred P. T1 - Microstructural characterization of porous materials by two-dimensional X-ray refraction topography N2 - X-ray refraction topography determines the internal surfaces and interfaces of non-metallic porous materials within the range of namometer to micrometer dimensions. The method is based on refraction of X-rays caused by interfaces of microstructures in heterogeneous materials. Generally, it permits a non-destructive full volume characterization of the pore topology. The X-ray refraction scanning technique make possible to visualize integral interface properties up to 10 μm spatial resolution by two-dimensional topographic images. It detects the spatially resolved internal surfaces of both, open and closed pores. Comparison to a certified powder reference of uniform grain size and known packing density reveals a quantitative measure for calibration requirements. An investigation on SiC- and Al2O3-ceramics illustrate the quantitative characterization of the internal surface density, pore sizes and their spatial distribution as well as local porosity fluctuations. KW - X-ray refraction topography KW - Al2O3 ceramics KW - Internal surface density KW - Porosity fluctuation KW - Pore size PY - 2004 DO - https://doi.org/10.1016/j.colsurfa.2004.04.074 SN - 0927-7757 SN - 1873-4359 VL - 241 IS - 1-3 SP - 225 EP - 229 PB - Elsevier CY - Amsterdam AN - OPUS4-11972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhl-Kuhn, Barbara A1 - Meyer, Klaus A1 - Klobes, Peter A1 - Fritz, Thomas T1 - Development of porous and dispersed CRM N2 - Abstract Porous and finely dispersed certified reference materials (CRM) were certified using the gas adsorption method. The special certification procedure for IUPAC isotherm classification types I, II, and IV is presented for meso- and macroporous materials with special emphasis on specific surface area, specific pore volume and pore width according to standards DIN 66 131, 66 134, and 66 135. Four CRMs (SiO2, f-Al2O3, two transition aluminas) with a macro- and mesopore range are presented. Certification was made on the basis of BCR guidelines in connection with interlaboratory tests (altogether 38 participating laboratories, 44 various gas adsorption apparatus). PY - 1998 SN - 0937-0633 VL - 360 IS - 3-4 SP - 393 EP - 397 PB - Springer CY - Berlin AN - OPUS4-11973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, P. A1 - Lannutti, J.J. A1 - Klobes, Peter A1 - Meyer, Klaus T1 - X-ray Computed Tomography and Mercury Porosimetry for Evaluation of Density Evolution and Porosity Distribution N2 - X-ray computed tomography (CT) and mercury porosimetry were combined to connect density gradients and the distribution of open porosity in a sintered compact. CT clearly showed that open porosity follows the initial distribution of low-density zones. Mercury porosimetry detected three distinct levels of porosity. Microstructural examination correlated the porosity level with the coordination of (i) two to three or (ii) multiple grains around pores. This combination of techniques provides a novel tool for the study of pore and density-gradient evolution during sintering. PY - 2000 DO - https://doi.org/10.1111/j.1151-2916.2000.tb01227.x SN - 0002-7820 SN - 1551-2916 VL - 83 IS - 3 SP - 518 EP - 522 PB - Blackwell Publishing CY - Malden AN - OPUS4-11955 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klobes, Peter A1 - Preiss, H. A1 - Meyer, Klaus A1 - Schultze, Dietrich T1 - Pore Formation During the Pyrolysis of C-Nb2O5 and C-Ta2O5 Xerogels N2 - Binary organic-inorganic gels have been prepared by mixing a carbonaceous hydrosol and a Nb2O5 or Ta2O5 sol derived by hydrolysis of the alkoxides. The gels are pyrolyzed under an inert atmosphere into precursors in which carbon and the metal oxides are mixed very intimately. High temperature treatment converts the precursors into the cubic face centered carbides. The precursors as well as the carbides have been shown to be micro- and mesoporous materials. Measurements of nitrogen adsorption reveal a characteristic change of the shapes of the isotherms (Type I → Type IV) and of the hysteresis loops (H4 → H2 → H1) during the thermal processes. Pore widening has been observed with rising temperature. The phenomena of crystallization, carbothermal reduction and sintering were found to control the pore shape and size. The results of the adsorption measurement correlate well with those of the thermoanalytical and X-ray diffraction studies. KW - Niobium and tantalum carbides KW - Gel KW - Adsorption isotherm KW - Pore size distribution KW - Thermal analysis PY - 1997 SN - 0026-3672 SN - 1436-5073 VL - 125 SP - 343 EP - 347 PB - Springer CY - Wien AN - OPUS4-11956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Preiss, H. A1 - Schultze, Dietrich A1 - Klobes, Peter T1 - Formation of NbC and TaC from Gel-Derived Precursors N2 - Binary hydrogels,. in which a niobium or tantalum oxide gel and a pyrolysable organic compound are combined, were prepared as preceramic materials. Carbonaceous gel or saccharose is used as the organic gel constituent, and alkoxides or peroxo acids are the starting materials for the transition metal component. Under pyrolysis at 600-700°C, the gels are transformed into carbide precursors in which a reactive carbon and finely dispersed oxide particles are mixed intimately. The subsequent carbothermal reduction proceeds at lower temperatures compared to physical mixtures of oxides and carbon black. The high-temperature treatment was monitored by TG/DTA, X-ray diffraction and nitrogen adsorption. Microporosity is generated in the temperature range 700-800°C, and mesoporosity is additionally formed at higher temperatures. The changes in porosity are controlled by the processes of crystallization, carbothermal reduction and sintering. The final products at 1400-1500°C are assemblages of fine particles of the face-centred cubic carbides with grain sizes of 1 µm and less. PY - 1997 SN - 0955-2219 SN - 1873-619X VL - 17 SP - 1423 EP - 1435 PB - Elsevier CY - Oxford AN - OPUS4-11957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Characterization of two micro-mesoporous activated carbons using gas adsorption, mercury porosimetry, small angle X-Ray scattering and raman spectroscopy T2 - Fourth International TRI/Princeton Workshop "Characterization of Porous Materials: From Angstroms to Millimeters" CY - Princeton, NJ, USA DA - 2006-06-21 PY - 2006 AN - OPUS4-12433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhl-Kuhn, Barbara A1 - Polzehl, J. A1 - Klobes, Peter T1 - Simultaneous confidence and prediction bands in the certification of pressure-volume curves for the pore size analysis of solids by means of mercury porosimetry N2 - The pore size analysis of solids is widely applied in chemical industries, materials engineering, ceramic production, environmental engineering, catalysis, chromatography, nanotechnology, and many other fields. In spite of several new methods used for determining the pore size distribution of meso- and macropores [see IUPAC Recommendations of 1994], mercury porosimetry has remained one of the most popular methods employed for the characterisation of porous materials. In this paper, a new way is described for the estimation of certified pressure-volume curves from experimental curves measured by different laboratories in connection with the certification of new reference materials for a comparatively low-pressure range of mercury intrusion (<2 MPa). Simultaneous confidence and prediction bands for the certified pressure-volume curves are constructed by bootstrapping. KW - Mercury intrusion KW - Certified reference material KW - Certified pressure KW - Volume curve KW - Bootstrap confidence bands KW - Bootstrap prediction bands PY - 2006 DO - https://doi.org/10.1007/s00769-006-0103-2 SN - 0949-1775 SN - 1432-0517 VL - 11 IS - 3 SP - 107 EP - 115 PB - Springer CY - Berlin AN - OPUS4-12520 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Normen und zertifizierte Referenzmaterialien für die Porenanalytik - Gegenwärtiger Stand und zukünftige Entwicklungen T2 - Herbsttagung 2005 des Arbeitskreises Kohlenstoff der Deutschen Keramischen Gesellschaft e. V. CY - Hardheim, Germany DA - 2005-10-20 PY - 2005 AN - OPUS4-11568 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Klobes, Peter T1 - Gasadsorption and mercury porosimetry on porous model glasses KW - Rock porosity KW - Nanoporous solids KW - Diffusion KW - Gasadsorption KW - Mercury porosimetry KW - C-14-PMMA impregnation KW - Nuclear waste disposal PY - 2006 SN - 952-478135-2 SN - 0785-9325 N1 - Serientitel: STUK-YTO-TR – Series title: STUK-YTO-TR IS - 215 SP - 1 EP - 45 PB - STUK CY - Helsinki AN - OPUS4-13197 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Klobes, Peter A1 - Meyer, Klaus A1 - Munro, R.G. T1 - Porosity and specific surface area measurements for solid materials KW - Poröse Materialien KW - Gasadsorption KW - Hg-Porosimetrie KW - Referenzmaterialien KW - Normen PY - 2006 UR - http://www.nist.gov/manuscript-publication-search.cfm?pub_id=854263 IS - 960-17 SP - 1 EP - 79 PB - U. S. Government Printing Office CY - Washington, DC AN - OPUS4-13943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Current state of the development and certification of porous reference materials T2 - 29 th ISO/TC24/SC4 meeting CY - Mainz, Germany DA - 2007-03-30 PY - 2007 AN - OPUS4-14665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - BAM-Referenzmaterialien als Beitrag zur Qualitätssicherung in der Analytik: Historie, aktueller Stand und neue Entwicklungen T2 - Workshop "Neueste Methoden der Analytik und deren industriell nutzbares Anwendungsmaterial", Materials Valley e.V., c/o Heraeus Holding GmbH CY - Hanau, Germany DA - 2012-04-19 PY - 2012 AN - OPUS4-25989 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Goebbels, Jürgen A1 - Klobes, Peter A1 - Bartels, J. A1 - Dietrich, H.-G. T1 - Analyse natürlicher Wegsamkeiten und ihrer Stimulationsmöglichkeiten in einem zementierten Aquifer durch Kombination von Röntgen-CT mit Quecksilberporosimetrie KW - Quecksilberporosimetrie KW - Computertomographie KW - Geothermie KW - Stimulation KW - Anhydritzement KW - Rhätsandstein KW - Allermöhe PY - 2000 SN - 0044-2259 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 46 IS - 3 SP - 153 EP - 156 PB - Schweizerbart CY - Stuttgart AN - OPUS4-1037 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter A1 - Minor, D. B. A1 - Röhl-Kuhn, B. A1 - Zimathies, Annett A1 - Prinz, C. A1 - Leigh, S. D. A1 - Heckert, N. A. A1 - MacDonald, B. S. T1 - Porosimetrie-Standard NIST SRM 1917 / CRM BAM-P 127 - Das erste von NIST und BAM gemeinsam zertifizierte Referenzmaterial T2 - 6. Workshop über die Charakterisierung von Feinteiligen und Porösen Festkörpern CY - Bad Soden, Deutschland DA - 2002-11-14 PY - 2002 CY - Bad Soden AN - OPUS4-1500 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harbich, Karl-Wolfram A1 - Fensch-Kleemann, Elisabeth A1 - Röhl-Kuhn, Barbara A1 - Klobes, Peter T1 - Nondestructive Characterization of Porous Ceramics by X-Ray Refraction N2 - X-ray refraction reveals the inner surface concentrations of porous materials within the range of (µm- to nm-dimensions. This technique is compared to mercury pressure porosimetry which is a standard method for pore size determination in porous solids. The mean pore size of several ceramics are investigated over a range of porosity between 30% to 60%. Complementary to high pressure mercury intrusion the refraction technique detects the spatially resolved inner surfaces of both, open and closed pores. Furthermore, X-ray refraction scanning topography visualizes integral interface properties up to 50 m spatial resolution by two-dimensional topographic images. Characteristic microstructure parameters, i. e. inner surface density, porosity and mean pore sizes of some Al2O3 and SiC ceramics are presented. The specific surface data of Al2O3 ceramics obtained from X-ray refraction agree well with the results given by mercury porosimetry. In contrast, the related mean pore sizes differs systematically by about 30%. T2 - 6th International Symposium on the Characterization of Porous Solids (COPS) CY - Alicante, Spain DA - 2002-05-08 PY - 2002 DO - https://doi.org/10.1016/S0167-2991(02)80198-7 SN - 0167-2991 VL - 144 SP - 693 EP - 699 PB - Elsevier CY - Amsterdam AN - OPUS4-1917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Klobes, Peter A1 - Röhl-Kuhn, Barbara ED - Kriegesmann, J. T1 - Einsatz der Quecksilberporosimetrie zur Grünkörpercharakterisierung - Aussagemöglichkeiten, Grenzen und Perspektiven PY - 2002 SN - 3-87156-091-X IS - Kap. 3.4.1.3 SP - 1 EP - 20 PB - Deutscher Wirtschaftsdienst CY - Köln AN - OPUS4-2003 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rübner, Katrin A1 - Goering, Harald A1 - Klobes, Peter A1 - Tschritter, H. ED - S. Kaskel, ED - P. Llewellyn, ED - F. Rodríguez-Reinoso, ED - N.A. Seaton, T1 - Investigation on the structure of silica/polyurethane nanocomposites T2 - 8th International symposium on the characterisation of porous solids CY - Edinburgh, UK DA - 2008-06-10 KW - Density KW - Dynamic mechanical analysis KW - ESW KW - Flammability KW - Nanocomposite KW - Polyurethane KW - Pore structure KW - Silica KW - Strength PY - 2009 SN - 978-1-84755-904-3 IS - Special Publication No. 318 SP - 150 EP - 158 PB - RSC AN - OPUS4-19411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Robens, E. A1 - Rübner, Katrin A1 - Klobes, Peter A1 - Balköse, Gulsum Devrim ED - Okada, C.T. T1 - Water vapour sorption and humidity - a survey on measuring methods and standards N2 - Under environmental conditions water exists in all three classical States of matter: solid, liquid and gas. The water molecule is non-linear and therefore polar. In comparison with other liquids water has anomalous features; about 63 exceptional properties are recorded. This article starts with reviewing properties of water, typical occurrences and definitions such as relative and absolute humidity and moisture content. Water is present everywhere in nature and engineering; it may be helpful or harmful. The survey concerns both: atmospheric hygrometry and usual measuring methods of the moisture content of solids and liquids as well as water Sorption. The determination of the atmospheric humidity is among the more difficult problems in metrology. In contrast, humidity determination of materials is simple; however the definition of the dry state is difficult. Because water is bound at and in solids and liquids in many different ways it tums out that the humidity content of materials is difficult to define and to measure accurately. We provide a survey on the measuring methods, describe the most important ones and discuss advantages and accuracy. In the search for extraterrestrial water special remote measuring methods have been developed analysing the spectrum of electromagnetic radiation either of natural sources or produced by a probe and reflected. Spacious deposits have been detected photographically. In situ investigations are made using conventional methods. With regard to the problems of measurements, Standardisation of measuring methods and procedures is required. There exist many institutions, which are engaged in investigating the use of water and standardising measuring methods. In tabular form, we give a survey on existing Standards. PY - 2011 SN - 978-1-61209-246-1 N1 - Serientitel: Environmental remediation technologies, regulations and safety – Series title: Environmental remediation technologies, regulations and safety IS - Chapter 1 SP - 1 EP - 91 PB - Nova Science Publishers, Inc. CY - New York AN - OPUS4-26290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, Klaus A1 - Klobes, Peter T1 - Comparison between different presentations of pore size distribution in porous materials KW - Pore size distribution KW - Porous materials PY - 1999 SN - 0937-0633 IS - 363 SP - 174 EP - 178 PB - Springer CY - Berlin AN - OPUS4-739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Klobes, Peter A1 - Wieland, Christoph A1 - Bruzzano, S. T1 - On the nanostructure of micrometer-sized cellulose beads N2 - The analysis of the porosity of materials is an important and challenging field in analytical chemistry. The gas adsorption and mercury intrusion methods are the most established techniques for quantification of specific surface areas, but unfortunately, dry materials are mandatory for their applicability. All porous materials that contain water and other solvents in their functional state must be dried before analysis. In this process, care has to be taken since the removal of solvent bears the risk of an incalculable alteration of the pore structure, especially for soft materials. In the present paper, we report on the use of small-angle X-ray scattering (SAXS) as an alternative analysis method for the investigation of the micro and mesopores within cellulose beads in their native, i.e., water-swollen state; in this context, they represent a typical soft material. We show that even gentle removal of the bound water reduces the specific surface area dramatically from 161 to 109 m² g-1 in cellulose bead sample type MT50 and from 417 to 220 m² g-1 in MT100. Simulation of the SAXS curves with a bimodal pore size distribution model reveals that the smallest pores with radii up to 10 nm are greatly affected by drying, whereas pores with sizes in the range of 10 to 70 nm are barely affected. The SAXS results were compared with Brunauer–Emmett–Teller results from nitrogen sorption measurements and with mercury intrusion experiments. KW - Small-angle X-ray scattering KW - Cellulose KW - Mesopores KW - Micropores KW - Porosimetry PY - 2011 DO - https://doi.org/10.1007/s00216-011-5176-z SN - 1618-2642 SN - 1618-2650 VL - 401 IS - 4 SP - 1101 EP - 1108 PB - Springer CY - Berlin AN - OPUS4-24251 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Feuchtemessung an Modellböden zur Nachbildung von Prozessen auf der Marsoberfläche T2 - XI. Workshop über die Charakterisierung von feinteiligen und porösen Festkörpern CY - Bad Soden, Germany DA - 2006-11-14 PY - 2006 AN - OPUS4-13806 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Porous CRM of BAM - An Overview T2 - XV. POROTEC-Workshop über die Charakterisierung von feinteiligen und porösen Festkörpern CY - Bad Soden, Germany DA - 2010-11-16 PY - 2010 AN - OPUS4-22567 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Investigation on the microstructure of ultra high performance concrete N2 - Ultra-high performance concrete (UHPC) is characterised by compressive strengths above 150 MPa and an outstanding durability. These properties are achieved by optimisation of the mixture composition, the mixing procedure as well as the curing conditions of the concrete. Heat curing as well as the use of vacuum mixers may contribute to the high strength. The very high brittleness of UHPC can be compensated by the addition of steel or polymer fibres. UHPC is produced using a very low water/cement ratio of 0.25 or smaller in combination with adding of polycarboxylate ether based superplasticisers. Furthermore, finest cements with contents of 500 kg/m³, defined selections of coarse and fine aggregates with a maximum grain size between 0.5 and 8 mm and fine pozzolanic (silica fume, fly ash) and inert additives (quartz filler) are used. In doing so, the aim is to obtain a very high packing density of the cement paste matrix and the aggregate/paste interface while a very homogeneous microstructure with a high calcium silicate hydrate (CSH) portion is formed. In the case of optimal mixing and curing conditions, UHPC contains almost no pores and microcracks. Therefore, studies of porosity and pore structure are very important to characterise UHPC materials in connection with the mixture optimisation. Here, the experimental results for UHPC are presented in comparison with those of high-strength concrete (100 MPa) and normal-strength concrete (35 MPa), respectively. T2 - 8th International Symposium on the characterisation of Porous Solids CY - Edinburgh, Scotland DA - 11.06.2008 PY - 2008 AN - OPUS4-16396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Dynamische wasserdampfsorption (DVS) als neue Messmethode an der BAM: Anwendungmöglichkeiten und erste Ergebnisse T2 - Abteilungsseminar, Abteilung I, BAM CY - Berlin, Germany DA - 2003-09-15 PY - 2003 AN - OPUS4-3711 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Porosimetry Standatd NIST SRM 1917 / CRM BAM-P 127: First Reference Material Jointly Certified by NIST and BAM T2 - The Third International TRI/Princeton Workshop "Characterization of Porous Materials:from Angstroms to Millimeters" CY - Princeton, NJ, USA DA - 2003-06-23 PY - 2003 AN - OPUS4-4766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Klobes, Peter A1 - Rübner, Katrin A1 - Hempel, S. A1 - Prinz, Carsten ED - S. Kaskel, ED - P. Llewellyn, ED - F. Rodríguez-Reinoso, ED - N.A. Seaton, T1 - Investigation of the microstructure of ultra high performance concrete T2 - 8th International symposium on the characterisation of porous solids CY - Edinburgh, UK DA - 2008-06-10 PY - 2009 SN - 978-1-84755-904-3 IS - Special Publication No. 318 SP - 354 EP - 361 PB - RSC AN - OPUS4-19401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - ZRM BAM-P108: Ein neues poröses Referenzmaterial mit großer BET-Oberfläche T2 - XII. Workshop über die Charakterisierung von feinteiligen und porösen Festkörper CY - Bad Soden, Germany DA - 2008-11-18 PY - 2008 AN - OPUS4-18122 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - 15 Years Development and Certification of Porous Reference Materials at BAM T2 - XV. POROTEC-Workshop über die Charakterisierung von feinteiligen und porösen Festkörpern CY - Bad Soden, Germany DA - 2010-11-16 PY - 2010 AN - OPUS4-22566 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter T1 - Feuchtemessung an Modellböden zur Nachbilidung von Prozessen auf der Marsoberfläche T2 - XI. Workshop über die Charakterisierung von feinteiligen und porösen Festkörpern CY - Bad Soden, Germany DA - 2006-11-14 PY - 2006 AN - OPUS4-13891 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klimakow, Maria A1 - Klobes, Peter A1 - Thünemann, Andreas A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Mechanochemical synthesis of metal-organic frameworks: A fast and facile approach toward quantitative yields and high specific surface areas N2 - The strategy of utilizing mechanochemical synthesis to obtain metal–organic frameworks (MOFs) with high surface areas is demonstrated for two model systems. The compounds HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate) and MOF-14 (Cu3(BTB)2, BTB = 4,4',4''-benzenetribenzoate) were synthesized by ball milling and characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal analysis (DTA/DTG/MS). The specific surface area (SSA) of both compounds was characterized by nitrogen adsorption. To verify these results and to understand how the synthetic conditions influence the pore structure and the surface area, additional small-angle X-ray scattering (SAXS) experiments were carried out. Our investigations confirm that this synthesis approach is a promising alternative method for distinct MOFs. This facile method leads to materials with surface areas of 1713 m²/g, which is comparable to the highest given values in the literature for the respective compounds. KW - Metal-organic frameworks KW - Mechanochemistry KW - Green-chemistry synthesis KW - Gas adsorption KW - SAXS KW - Specific surface area PY - 2010 DO - https://doi.org/10.1021/cm1012119 SN - 0897-4756 SN - 1520-5002 VL - 22 IS - 18 SP - 5216 EP - 5221 PB - American Chemical Society CY - Washington, DC AN - OPUS4-21999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rouquerol, J. A1 - Baron, G. A1 - Denoyel, R. A1 - Giesche, H. A1 - Groen, J. A1 - Klobes, Peter A1 - Levitz, P. A1 - Neimark, A.V. A1 - Rigby, S. A1 - Skudas, R. A1 - Sing, K. A1 - Thommes, M. A1 - Unger, K. T1 - Liquid intrusion and alternative methods for the characterization of macroporous materials (IUPAC technical report) N2 - This document deals with the characterization of porous materials having pore widths in the macropore range of 50 nm to 500 µm. In recent years, the development of advanced adsorbents and catalysts (e.g., monoliths having hierarchical pore networks) has brought about a renewed interest in macropore structures. Mercury intrusion–extrusion porosimetry is a well-established method, which is at present the most widely used for determining the macropore size distribution. However, because of the reservations raised by the use of mercury, it is now evident that the principles involved in the application of mercury porosimetry require reappraisal and that alternative methods are worth being listed and evaluated. The reliability of mercury porosimetry is discussed in the first part of the report along with the conditions required for its safe use. Other procedures for macropore size analysis, which are critically examined, include the intrusion of other non-wetting liquids and certain wetting liquids, capillary condensation, liquid permeation, imaging, and image analysis. The statistical reconstruction of porous materials and the use of macroporous reference materials (RMs) are also examined. Finally, the future of macropore analysis is discussed. KW - Capillary condensation KW - Image analysis KW - IUPAC physical and biophysical chemistry division KW - Liquid intrusion KW - Macroporous materials KW - Mercury prorsimetry KW - Permeation KW - Pore size characterization KW - Reference porous materials KW - Statistical reconstruction of porous solids PY - 2012 DO - https://doi.org/10.1351/PAC-REP-10-11-19 SN - 0033-4545 SN - 1365-3075 VL - 84 IS - 1 SP - 107 EP - 136 PB - Union CY - Research Triangle Park, NC AN - OPUS4-26109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klimakow, Maria A1 - Klobes, Peter A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Characterization of mechanochemically synthesized MOFs N2 - The compound MOF-14 (Cu3(BTB)2, BTB = 4,4',4''-benzenetribenzoate) was synthesized by ball milling and characterized by powder X-ray diffraction (XRD). The raw material was activated using an efficient single washing step to ensure a free pore access. Nitrogen adsorption measurements were carried out to determine the specific areas of the samples before and after activation. To interpret the activation process in terms of blocking effects in the micropore channels, NLDFT evaluations (Nonlocal Density Functional Theory) of the MOF-14 nitrogen isotherms were carried out. In connection with the appearance of additional hysteresis loops in the nitrogen isotherms, calculations of the mesopore size distribution were performed using the method of Barret, Joyner, and Halenda (BJH). The results are compared to those of a structurally analogue MOF, namely HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate). This comparison showed notable differences regarding the impact of the activation step on the formation of mesopores and their size distribution. KW - Metal-organic frameworks KW - Mechanochemistry KW - Gas adsorption KW - Specific surface area KW - MOF-14 PY - 2012 DO - https://doi.org/10.1016/j.micromeso.2011.11.039 SN - 1387-1811 SN - 1873-3093 VL - 154 SP - 113 EP - 118 PB - Elsevier CY - Amsterdam AN - OPUS4-25597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klobes, Peter A1 - Thormann, A. T1 - Porosity Characterisation of Nanoporous Alumina Membranes T2 - XII. Workshop über die Charakterisierung von feinteiligen und porösen Festkörpern CY - Bad Soden, Germany DA - 2008-11-18 PY - 2008 AN - OPUS4-18148 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -