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- Radar (39)
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- 7.1 Baustoffe (4)
- 2 Prozess- und Anlagensicherheit (3)
- 3 Gefahrgutumschließungen; Energiespeicher (3)
- 4.5 Kunst- und Kulturgutanalyse (3)
Bottom ash from municipal solid waste incineration (MSWI) consists of eiemental metals in considerable amounts. The fine fraction < 4 mm additionally contains chemically bound metals (oxides, carbonates, Silicates). Separation prospects with techniques as in ore processing (flotation, density separation, bioleaching, hydrothermal solution) are discussed. During alteration after wet extraction mineral material with hydraulic properties form coatings on almost all particles of the bottom ash and complicate separation procedures. ln addition bottom ash from MSWI is a heterogeneaus material. For sufficient enrichment different concerted treatment steps seemed to be essential associated with an uncertainty of economic viability. The utilisation of metal compounds present in bottom ash as secondary raw material depends on the energy- and resource-efficiency of the enrichment processes. Therefore energy and material flow considerations are presented.
To resist the corrosive geothermal environment during carbon capture and storage CCS -such as: heat, pressure, salinity of the aquifer, CO2-partial pressure, properties of pipe steels-require certain specification. For evaluation samples of differently heat treated high alloyed stainless injection-pipe steels AISI 420 X46Cr13, AISI 420J X20Cr13 as well as X5CrNiCuNb16–4 AISI 630 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h up to 8000 h in a CO2-saturated synthetic aquifer environment similar to a possible geological situation in the northern German Basin. Corrosion rates and scale growth are lowest after long term exposure for steels hardened and tempered at 600 °C to 670 °C and pits -indicating local corrosion- decrease in diameter but increase in number as a function of carbon content of the steel. Martensitic microstructure is preferred with respect to these particular conditions.
Naturwissenschaftliche Verfahren gewinnen zunehmend an Bedeutung bei der Untersuchung von Kunst und Kulturgut und bei der Entwicklung von Konservierungskonzepten zum Erhalt des kulturellen Erbes.
Neben bildgebenden Verfahren wie der Computertomographie oder der Radiographie sind materialanalytische Verfahren von großer Wichtigkeit. Durch die Miniaturisierung elektronischer Bauteile kommen immer mehr mobile Untersuchungstechniken auf den Markt, so dass Kulturgüter vor Ort im musealen Kontext untersucht werden können.
Über den Stand der Entwicklung von Ultraschallprüfverfahren für grobkörnige austenitische Werkstoffe
(1985)
More information about the capability and especially about the durability of structural sealant glazing (SSG) systems are needed. To make a contribution to unanswered questions, a suitable system evaluation test is necessary. The basis for such a test is a load function, which accounts for the decisive loads SSG systems are exposed to during their working life. This paper proposes a general load function for standard SSG systems at central German locations for accelerated durability tests. Decisive loads are determined and different SSG construction types defined. The performance of these SSG systems under exposure to external loads and to a dynamic pendulum impact is investigated via finite element analyses using a hyperelastic material model. The external loads are applied separately and superimposed. Compression, tensile, and shear deformations of the sealant are determined. It is found that the sealant is subjected to normal and shear stresses simultaneously. The requirements for a representative specimen are derived. The results will be taken as basics for the development and the construction of a test facility to evaluate the durability of structural sealant glazing systems.
Structural sealant glazing (SSG) is an impressive technical response to the challenges of modern structural design. The evaluation of fitness for use as well as durability is a precondition for approval of SSG-façades by building authorities because of their special safety relevance. However, the potential of the actual evaluation methodology to reproduce performance as well as durability under real use conditions is generally assessed to be limited. The concept so far is criticized as mainly single-loading and incomplete in comparison to the real use conditions. The exercised separation of the in reality interacting loading effects is assessed as insufficient and inadequate to explore performance. Consequently, the performance and capability of SSG-solutions is only fragmentarily explored. However, the most restricting argument so far is the deficit of the actual test methodology for life cycle prognosis under interacting mechanical as well as climatic loads. Because of the limited acceptance, additional structural design conditions are imposed by the authorities. Besides this restriction, there is also an increasing demand by the authorities, architects, and users for determinable working life cycles, not least under economic aspects. That is why knowledge, particularly regarding SSG-performance and durability, must be expanded. Together with partners representing all branches involved in façade engineering (engineering design, sealant producer, applicator, and cladding company) the Federal Institute for Materials Research and Testing (BAM) develops a new system test focused on the substrate–sealant–glass panel interaction. With it, a new comprehensive dynamic–mechanical evaluation methodology already introduced at the fourth Symposium in Anaheim, CA, in 2011 shall be complemented by a performance-related system test. Subject-matter of this contribution is the presentation of a new dynamic–mechanical system test method and its first experimental application on SSG-systems. We describe our approach beginning with the discussion of relevant load effects on sealant joints and with the help of a highly generalized finite element (FE) analysis. Resulting from a parameter study of various load combinations acting on different SSG-construction types, we derive a practicable deformation load function from the decisive load categories taking into account regular as well as extraordinary loads. Assumptions and procedures to quantify their parameter values (regarding the effective direction and order of deformation magnitude affecting the substrate–sealant–glass bond) are discussed. The calculated decisive sealant deformations resulting from the parameter study are validated by simplified mechanical plausibility tests. Subsequently, the transfer of the findings about the substrate–sealant–glass panel bond loading into the design and construction of an adapted system test specimen and the development of a multifunctional test facility is introduced. The multi-functional applicability of the system test device is discussed. On the basis of results during our actual operational checks, first ideas about system performance and durability under superimposed loading are presented. A validation of this new test methodology by comparison to test results of disassembled samples and in situ results is a task for separate research activities.
Monitoring of cracks in historic concrete structures using optical, thermal and acoustical methods
(2015)
Cracks are a major issue in the field of cultural heritage. In order to evaluate the significance of a crack, a long term monitoring of the damaged region is required. However, there is a lack of easy to operate tools for such monitoring measures. Therefore, new or existing methods for other applications have to be optimised for cultural heritage investigation. The paper describes the application of such crack observation methods on a historic concrete sculpture. Beside conventional methods, like mapping by hand and ultrasonic depth profiling, a novel tracking system is presented. Furthermore, the suitability of active thermography for the investigation of cracks was investigated. The results show promising prospects for these non-destructive techniques.
Evaluation of an interlaboratory comparison of the chemical assay of U, Th oxide coated particles
(1981)
The risk assessment of total petrol hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAH), two of the most frequent soil and water contaminants, has to include their exposure pathways, especially the soil groundwater pathway. Threshold values have to be aquired for the amendment to the German Federal Soil Protection Contaminated Sites Ordinance. For this purpose, a batch experiment with a liquid to solid ratio (L/S) of 2 L/kg was developed. Aim of this work was to verify the robustness of this leaching procedure for TPH and PAH in different soil types against varying test conditions. Also, stir bar sorptive extraction (SBSE) was tested as alternative sample preparation of eluates for PAH analysis.
Wie viele Forschergruppen, haben auch wir uns das langfristige Ziel gesetzt, einen Beitrag bei der Beantwortung der Frage zu leisten, was Hunde riechen, wenn sie Krebs erschnüffeln.
Dabei sollen die Hunde nicht nur anzeigen, ob eine Atemluftprobe positiv oder negativ ist, sondern sie sollen auch aktiv eingebunden werden in den systematischen Suchprozess nach detektierbaren Biomarkern. So ist geplant, dass mittels eines präparativen Fraktionssammlers definierte Schnitte des Gaschromatogramms einzeln oder in möglichen Kombinationen auf das Adsorbervlies gebracht werden, um im Hundetraining eingesetzt zu werden. In analoger Weise könnte auch mit spezifischen Kandidatensubstanzen verfahren werden.
The inevitable increase of torque or load, because of lightweight approaches, pushes the oil-film temperatures on the teeth flanks of gears above 200°C, and requires alloys with higher strength and toughness properties. Furthermore, the real temperature on surfaces during the physical vapor deposition (PVD) or chemical vapor deposition (CVD) of thin films can exceed the annealing temperature of the state-of-the-art bearing and gear materials, such as AISI 52100 (1.3505), 16MnCr5 (1.7131), 21NiCrMo (1.6523), and 30CrMoV9 (1.7707). Such trends call for slip-rolling-resistant, alternative alloys suited for contact stresses above P0max of >2.2 GPa. The tribological profile under slip-rolling conditions at 120°C in a factory engine oil (SAE 0W-30, ACEA A3/B4, ν120°C = 5.33 mPa, HTHS150°C = 3.0 mPa) until 10 × 106 load cycles between P0max of 2.25 GPa to 3.92 GPa of uncoated 100Cr6 (1.3505, PBQ), 102Cr6 (1.2067), Cronidur 30 (1.4108, DESU), 45SiCrMo6 (1.8062, CVEM), 40SiNiCrMo1 [vacuum arc remelting (VAR)], CSS-42L (AMS 5932, vacuum induction melting (VIM)-VAR, and carburized), 36NiCrMoV1-5-7 (CAB), ASP2012 (ASP), and 20MnCr5 (1.7131, carburized) was established in twin disk machines (Amsler-type and 2Disk). The present benchmark illuminates the tribological impact of uncoated bearing steels in comparison to uncoated alternative steel alloys on friction, wear and slip-rolling resistance, as well as load carrying capacity. Iron-based steel alloyed with silicon or molybdenum reduces alloying costs and avoids thermo-chemical treatments. This benchmark suggests considering an extension to fracture toughness from hardness and strength as a relevant property for slip-rolling alloys. If slip-rolling resistant, the wear rates of the metallurgical different steels were more or less within one order of magnitude, but the influence of increasing contact stresses on the tribological profile differed significantly.
Im Zusammenhang mit Planungs- und Entwicklungsaufgaben, den Forderungen in Normen und Regelwerken, in betrieblichen Arbeitsanweisungen, den Vorgaben für Zulieferteile oder bei der Auseinandersetzung mit Schadensfällen stellen sich häufig Fragen zum Korrosionsschutz sowie zu entsprechenden Prüf- und Untersuchungsverfahren. Die daraus gewonnenen Ergebnisse sollen z. B. eine Eignung von Werkstoffen oder Schutzsystemen unter spezifischen Einsatzbedingungen, die Dauerhaftigkeit des Schutzes, den Nachweis einer gleichbleibenden Qualität, die Vergleichbarkeit bekannter mit neuen Korrosionsschutzkonzepten oder den Wirkungsnachweis für gezielte Systemeingriffe belegen. Schnell wird deutlich, dass sich aus dem Blickwinkel verschiedener Branchen ganz unterschiedliche Anforderungsprofile ergeben, die ihren Niederschlag dann in unterschiedlichen Strategien der Prüf- und Untersuchungsverfahren finden.
The use of open GIS standards offers a broad variety of potential, particularly in the field of data exchange, data storage, and interoperability. GML and CityGML are excellent examples for the ontological description of real world objects by means of an open standard whereas SensorML serves to describe measurements, sensors and measuring platforms. The use of such standards offers not only the possibility of using a common standardised language, but also the use of open service standards. The combination of spatial data and sensor standards in services and service-oriented architectures goes far beyond previous existing solutions on the market and provides a novel platform for monitoring structures. That in fact is far more than a simple data storage model. The methods and models presented in this contribution allow a direct integration of sensor data and its provision through an open standard language. In this case, all the intermediate steps at any time through an open service interface are addressed and may be made available and provided to different actors and stakeholders participating in a construction scenario. The great potential and the added value of such an information system is the permanent availability of measurement and object data and an associated integrated analysis of sensor data in combination with a finite element model (FEM). The automatic derivation of a finite element model from the 3D structure model, the visualisation of FEM, the provision of raw (measurement) data and sensor information for each time of measurement transform the platform into a universal tool in the field of structural monitoring. This contribution introduces the individual components, the standards used and the interaction between the components to an overall system.
El sólido vínculo entre las instituciones sociales de control de la calidad y la innovación no siempre resulta obvio. En los párrafos que siguen se sostiene que los servicios de normalización, metrología, evaluación del cumplimiento de las normas y acreditación prestados por la Infraestructura Nacional de la Calidad (INC) son grandes propulsores de nuevos avances sociales y tecnológicos. Todos los elementos de la infraestructura de la calidad ayudan a la sociedad a hacer frente a distintos desafíos en un entorno cambiante, mediante la creación y difusión de nuevas tecnologías.
Quantitative online NMR spectroscopy of technical mixtures: on the fly quantification of fluids
(2014)
In this paper quantitative NMR spectroscopy is demonstrated as a tool for process analytical technology (PAT) in order to obtain real time information from dynamic processes. Different methods for quantification are presented and as a result the limit of detection for NMR measurement could be determined to 3.3 mg kg-1 (ethanol in water). As model processes esterification reactions and dissolution of pharmaceutical formulations are presented and important process parameters are extracted. Furthermore it is demonstrated that not only 1H-NMR spectroscopy can be used for process monitoring but also 13C-NMR for technical mixtures.
Characterization of randomly branched polymers utilizing liquid chromatography and mass spectrometry
(2014)
Branching in polymers is an important way to modify the materials properties, however the characterization of random branching in polymeric materials is a challenge in polymer analysis. In this work, liquid adsorption chromatography methods are developed for a commercially available hyperbranched polyester (Boltorn™). This Chromatographie techniques was then coupled to offline MALDI-TOF MS analysis, a first in the analysis of randomly branched polymers. The coupling of these two techniques provides superior MALDI-TOF spectra, enabling the easy identification of structural subdistributons based on theoretical molecular weight. Detailed analysis of the MALDI-TOF spectra shows that these Chromatographie conditions separate cyclic Boltorn polymers (with no core molecule) from non-cyclic polymers (with core molecule), and these are the only two architectures observed. MALDI MS also confirms that the Chromatographie Separation mode is adsorption, but further analysis is needed to determine if there is a Separation by degree of branching.
The ground vibrations, which are generated by trains on different tracks, have been calculated by finite-element boundary-element models. The ballasted track is modelled in detail by the finite element method. The infinite soil is modelled by the boundary element method as a homogeneous or layered half-space. The track-soil system is coupled to a simple rigid mass model of the vehicle so that the vehicle-track interaction is completely included. Transfer functions are calculated in frequency domain without and with vehicle-track interaction, the compliance of the track and the mobilities of the soil at different distances from the track. Finally, the ratios between the ground vibration amplitudes with and without mitigation measures are calculated to quantify the effectiveness of the mitigation measures.
Tracks with under-sleeper pads have been investigated in a wide parameter study for the RIVAS project. The main parameters that influence the reduction of ground vibration are the stiffness of the under-sleeper pad, the mass and the width of the sleeper. The softest sleeper pad yields the best reduction of the ground vibration. The influence of the sleeper mass is not so strong, as the characteristic frequency is ruled by the mass of the sleeper and the mass of the wheelset as well.
For the accuracy of inertial navigation systems for indoor localization it is important to get high quality sensor data of the multi-sensor system. This can be realized using high quality sensors or the developed 3D-self-calibration-method for low cost sensors. Based on the calibration procedure of the accelerometer (ACC) and the magnetic field sensor (MAG), the additional integration of the gyroscope (GYRO) leads to a reduction of the indoor positioning error. This improves both the approximation for the accelerometer, the magnetic field sensor and the gyroscope so that the standard deviation of a single sensor is minimized. There are errors in the whole system. To determine these error sources it is important to define the measurement uncertainty. In this paper it is presented that the measurement uncertainty can be reduced by the application of the developed 3D-self-calibration method.
The efficiency of wood gasification can be improved by applying membrane based gas separation operations in several of its sub-processes. In the present study the use of membranes made of hardened cement pastes for this purpose was investigated to provide a low cost alternative to conventional membrane materials. The pastes were tested for their diffusional properties in a Wicke-Kallenbach cell and analyzed with regard to their pore structure. The use of low water to binder ratios and slag and/or pozzolans led to a finer pore structure and higher separation factors; in particular, an approximately linear dependence of the separation factors on the threshold radii was observed. The results implicated that Knudsen diffusion is the prevailing diffusion mechanism in the membranes. Deviations from the theoretically expected separation factors were found, which may be ascribed to concentration polarization and channeling effects.
In diesem Beitrag werden Untersuchungsergebnisse vorgestellt, die den Einfluss von Mikrosilica auf die Selbstaustrocknung und das damit verbundene autogene Schwinden der Bindemittelmatrix von Hochleistungsbetonen beschreiben. Die dadurch hervorgerufenen Schädigungsprozesse wurden mit Hilfe von zerstörungsfreien Prüfmethoden verfolgt. Dabei zeigte sich, dass eine durch äußeren Zwang bedingte Mikrorissbildung durch Schallemissionsanalyse detektiert werden kann.
The selective compression of quick response (QR) and Data Matrix code carriers based on shape memory polymer (SMP) with a freely configurable steel ball type indenter and adjacent thermo-mechanical shape fixing gave notched, room temperature (23 °C) stable, temporary shapes with non-decipherable codes. The microscopic investigation of cryomicrotome sections unveiled indentation-related shape fixities of about 90 %. Independent of the selected two-dimensional code, the triggering of the SM effect resulted in sufficient shape recoveries to restore the code readability so that a maximum number of characters including 122 for a QR code (version 7) and 112 in case of a Data Matrix code (version 12) could be read with a scanning and decoding device. Due to the large number of difficult to copy shapes with on demand releasable information, SMPs may serve as viable information carriers for product and brand protection applications.
In einer arbeitsteiligen Wirtschaft erfüllt der Transport eine herausragende Scharnierfunktion. Von der Wirtschaftlichkeit, Zuverlässigkeit und Sicherheit des Transportes hängen vielfältige Arbeitsergebnisse in den unterschiedlichen Prozessen ab. Aus den Bedürfnissen der Wirtschaft ergibt sich i.d.R. ein sogenannter Modal-Split, der die Aufteilung der Wirtschaftsgüter auf die verschiedenen Verkehrsträger Straße, Schiene, Binnenschiff, See und Luft beschreibt. Zuverlässigkeitsangaben und auch Angaben zur Sicherheitslage lassen sich aus den Statistiken herleiten, wie sie z.B. für Deutschland (Statistisches Bundesamt) und Europa (Eurostat) vorliegen. Die Unfallzahlen sind relativ gering, insbesondere aber ist die Tendenz einer stetigen Verringerung der Ereignisse pro Transport zu erkennen.
Der Transport gefährlicher Güter ist integrativer Teil des allgemeinen Gütertransportes und demzufolge erfolgen die Transporte mit Gefahrgut auf den gleichen Verkehrswegen ohne nennenswerte Sonderstellungen, abgesehen von Spezialfällen, wie Transporte für die Bundeswehr. Für die Transporte gefährlicher Güter gibt es spezielle Regelungen, die für die verkehrsträgerunabhängigen Bereiche einheitlich von den Vereinten Nationen ausgearbeitet und als sogenannte Modellvorschriften veröffentlicht werden. In einem Rhythmus von zwei Jahren werden diese Modellvorschriften der Vereinten Nationen dem Stand der Technik angepasst, sodass quasi kontinuierlich die Optimierung der Regelsetzung erfolgt.
Man kann heute davon ausgehen, dass der materielle Inhalt der Regeln der Vereinten Nationen in den wichtigsten Wirtschaftsregionen der Welt in entsprechenden bindenden Regeln seinen Niederschlag gefunden hat, sodass von einem nahezu einheitlichen Regelwerk für den Transport gefährlicher Güter auf der ganzen Welt ausgegangen werden kann.
Hydrogen embrittlement (HE) is a widely known phenomenon and under investigation already for more than a century. This phenomenon, though thoroughly studied, is not yet completely understood, and so far, there are several suggested mechanisms that try to explain the occurrence of HE. One important factor of understanding the HE phenomenon and predicting hydrogen-assisted failure is the descent knowledge about the hydrogen transport behaviour in the material. Neutron radiography is a proven method for tracking hydrogen diffusion and it was applied successfully in various research studies. In the presented study, we examined the hydrogen effusion behaviour in duplex stainless steel by means of neutron radiography and calculated the effective diffusion coefficient from the obtained transmission images.
High strength structural steels are susceptible to hydrogen embrittlement. A critical combination of stress, amount of diffusible hydrogen and microstructure is believed to cause cold cracking. Especially during welding of high strength structural steels high tensile residual stresses may develop. Therefore, a feasibility study was conducted using synchrotron X-ray diffraction in order to analyze the stress–strain behavior during tensile loading. For that purpose two types of steel showing different hardening mechanisms were used. On the one hand a thermo-mechanically treated S1100MC and on the other hand a quenched and tempered S1300Q were chosen. The samples were electrochemically charged with hydrogen and subsequently stored in liquid nitrogen to prevent effusion. Tensile tests of the samples were conducted in a special load frame allowing for tilting the samples while applying constant loads. High energy synchrotron radiation was used for energy dispersive X-ray diffraction (EDXRD) analysis in transmission geometry. This method offers the possibility for measuring several diffraction lines of all contributing crystalline phases of the material. Strains as well as stresses applying the sin²ψ-method were determined for varying load situations. This feasibility study shows how the interaction of hydrogen and the stress/strain response may be assessed by diffraction methods. Examples are presented showing that hydrogen alters the load distribution as well as the strain behavior between different lattice planes in high strength steels.
As more offshore wind parks are commissioned, the focus will inevitably shift from a planning, construction, and warranty focus to an operation, maintenance, and investment payback focus. In this latter case, both short-term risks associated with wind turbine component assemblies, and long-term risks related to integrity of the support structure, are highly important. This research focuses on the role of condition monitoring to lower costs and risks associated with short-term reliability and long-term asset integrity. This enables comparative estimates of the life cycle costs and reduction in uncertainty, both of which are of value to investors.
Im Rahmen einer Bachelorarbeit und in Kooperation mit der Bundesanstalt für Materialforschung und -prüfung (BAM) wurden die eintretenden Schädigungsprozesse während des Spaltzugversuche mittels innovativer Prüfverfahren untersucht. Ziel war es, in Untersuchungen Erkenntnisse über das Versagensverhalten unter statischer und dynamischer Spaltzugbeanspruchung bei der Variation verschiedener Einflussfaktoren zu gewinnen. Hierfür wurde die Aussagekraft innerer und äußerer Schädigungsindikatoren zur Charakterisierung der auftretenden Bruchmechanismen analysiert.
The glass transition behavior of ultra-thin supported polymer films is discussed controversially in the literature for around 20 years. Substantial efforts have been archived to understand it. In this contribution, a combination of methods sensitive to bulk properties of a system, like dielectric or specific heat spectroscopy with surface analytics, for instance, atomic force microscopy (AFM), contact angle measurements, and X-ray photoelectron spectroscopy (XPS) were employed to study the glass transition of ultra-thin supported films. All investigations were carried out on identically prepared and treated samples. Different systems with different complexities going from more or less flexible homopolymers over rigid main chain macromolecules to polymer blends have been studied. For the investigated flexible macromolecules, the dynamic glass transition temperature estimated within the frame of the linear response approach is independent of the film thickness down to several nanometers and identical to the bulk value. For polystyrene it was found the thermal glass transition temperatures can depend on the film thickness. This different behavior is not well understood till now and needs further experimental clarification. For the investigated main chain polymers polycarbonate and polysulfone. Dynamic and thermal glass transition temperature estimated from the dielectric measurements increases with decreasing film thickness. This is discussed in the frame of a strong interaction of the polymer segments with the surface of the substrate. In general for homopolymers, the interaction energy of the polymer segments with the substrate surface cannot be considered as the only parameter, which is responsible for the change in the thermal glass transition with the film thickness. For the investigated miscible blend system of polystyrene/poly(vinyl methyl ether) at a composition of 50/50 wt-% a decrease of the dynamic glass transition temperature with decreasing film thickness is found. This is explained by the formation of a poly(vinyl methyl ether)-rich surface layer with a higher molecular mobility.
Wear
(2014)
Original equipment manufacturers (OEMs) and end-users perceive “wear” or “oil drain” differently. Spare parts, Services, and accessories contribute to an important portion to the profit of the OEMs. Maintenance and shutdowns define the operational costs of end-users. Thus, the strategy in order to exploit “wear” depends from the market structure and is up to the reader and/or applicant. The topic “Service Life/Durability/Life Cycle” represents a very ambiguous one and was already thematized in earlier times.
Tribosystems
(2014)
A tribosystem is an entity with a structure of interacting components in relative motion to perform a technical function.
Note 1 Function and structure of tribosystems may be detrimentally influenced by frictioninduced energy dissipation and wear-induced materials degradation.
Note 2 Friction and wear in tribosystems can be mitigated by lubricants and lubrication.
Stribeck curve
(2014)
The importance of lubricants in virtually all fields of the engineering industry is reflected by an increasing scientific research of the basic principles. Energy efficiency and material saving are just two core objectives of the employment of high-tech lubricants. The encyclopedia presents a comprehensive overview of the current state of knowledge in the realm of lubrication. All the aspects of fundamental data, underlying concepts and use cases, as well as theoretical research and last but not least terminology are covered in hundreds of essays and definitions, authored by experts in their respective fields, from industry and academic institutes.
Polyalkyleneglycols are oxygen containing base oils, which enable a) polymer-free formulations with high intrinsic viscosity indices favorable for fuel economy, b) bio-no-tox properties and c) low viscosity formulations with low evaporaions. The oxygen present in each monomer of the backbone of polyalkylene glycols defines intrinsic properties, such as high viscosity indices, low NOACK-evaporation, extreme pressure, high hear capacities, etc., thus enabling metal-, ash- and polymer-free engine oil formulations supporting the functional benefits, such as improved of fuel economy or no adverse effects on after-treatment devices.
Fretting
(2014)
The importance of lubricants in virtually all fields of the engineering industry is reflected by an increasing scientific research of the basic principles. Energy efficiency and material saving are just two core objectives of the employment of high-tech lubricants. The encyclopedia presents a comprehensive overview of the current state of knowledge in the realm of lubrication. All the aspects of fundamental data, underlying concepts and use cases, as well as theoretical research and last but not least terminology are covered in hundreds of essays and definitions, authored by experts in their respective fields, from industry and academic institutes.
Coatings for slip-rolling
(2014)
Quando se constrói uma estrutura, na maioria das vezes, não se sabe ao certo até quando esta será necessária, útil ou ainda, segura.
No projeto utilizam-se características conhecidas dos materiais, como resistência à compressão, resistência a ataques químicos e a intempéries, além de expectativas de carregamento e condições de exposição em uso. Porém, as reais interações entre a estrutura e o ambiente no qual ela está inserida são difíceis de prever ou simular. Além do carregamento em uso, que pode variar de forma diferente do previsto (incremento de tráfego sobre uma ponte ou modificação de uso de um edifício, por exemplo), outra questão são as sobrecargas acidentais, como terremotos, inundações, etc. Todas estas incertezas fazem com que a uma previsão precisa da degradação da estrutura ao longo do tempo seja difícil (quase impossível). Para confirmar a segurança e a fidelidade da estrutura em relação ao projeto são feitas inspeções, que avaliam a degradação, a segurança e as condições gerais da estrutura. Podem-se citar como principais usos do monitoramento estrutural na engenharia civil: auxiliar as inspeções provendo ao especialista um histórico de degradação e comportamento que possibilita um melhor entendimento de possíveis problemas e a identificação de causas; certificar uma estrutura em relação à fidelidade ao projeto; avaliar a segurança de uma estrutura antiga ou num dado momento em que condições especiais se apresentem; e otimizar programas de manutenção.
This paper provides an overview about state of the art methods in the field of plasma spectrometry and its application in material science. Different types of plasmas with their special characteristics for various applications are described. Indirect analytical methods involving sample digestion and often also analyte/matrix separation prior to analyzing the samples still represent the most important routine methods. Here, plasma optical emission and mass spectrometry are the most frequently used determination techniques with a wide variety of instruments commercially available. To avoid the risk of analyte loss or of contaminations during an often time consuming and laborious sample preparation, the use of techniques with direct solid sampling is considered an attractive alternative for the analysis of many materials. A survey on applications with a special focus on direct solid sampling techniques such as GDMS, GD-OES, LA-ICPMS, ETV-ICPMS, ETV-ICP-OES, DC-Arc is given. Different possible calibration strategies are discussed.
Biolubrifiants
(2013)
Les huiles perdues, les fuites accidentelles et les lubrifiants perdus rejoignant les sols et les eaux (comme ce fut le cas pour le lac de Constance par exemple) sont l'un des points de departs de la mise en route des lubrifiants « neutres pour l'environnement».
Meme en prenant en compte les voies du recyclage, la combustion dans les moteurs et les fuites connues, environ 30 % (entre 20 % et 40 %, selon les etudes du votume de lubrifiants entrent dans l'environnement par des voies non maitrisees ou sont probablement mis en decharge de maniere illegale. Avec de tels chiffres publies, les arguments des lobbyistes de l'industrie petrochimique, affirmant que, dans la plupart des applications, les fluides sont enfermes dans des reservoirs dos et etanches, ne convainquent pas les politiques. C'est aussi peut-etre parce qu'en Allemagne, environ 60 % des particuliers changent leur huile eux-memes.
Dans une annee d'economie normale, environ 4,5 millions de tonnes de lubrifiants neufs sont vendues dans l'Europe des 15.
This review gives representative examples of the various types of synthetic cationic polymers or polyampholytes (chemical structure, architecture, etc) that can be used to complex DNA (forming polyplexes) for their application in gene delivery. In designing polycations for gene delivery, one has to take into account a balance between protection of DNA versus loss of efficiency for DNA condensation and efficient condensation versus hindering of DNA release. Indeed, if the polyplexes are not stable enough, premature dissociation will occur before delivery of the genetic material at the desired place, resulting in low transfection efficiency; on the other hand, a complex that is too stable will not release the DNA, also resulting in low gene expression. The techniques generally used to determine these properties are gel electrophoresis to test the DNA/polymer complexation, ethidium bromide or polyanion displacement to test the affinity of a polymer for DNA, and light scattering to determine the extent of DNA condensation. Moreover, with the development of more precise instruments for physico-chemical characterization and appropriate biochemical and biophysical techniques, a direct link between the physico-chemical characteristics of the polyplexes and their in vitro and in vivo properties can be drawn, thus allowing tremendous progress in the quest towards application of polyplexes for gene therapy, beyond the research laboratory.
Blei weist in der Natur die vier stabilen Isotope 204Pb, 206Pb, 207Pb und 208Pb auf, mit den entsprechenden Isotopenhäufigkeiten von 1,4%, 24,1 %, 22,1 % und 52,4 %686. Dabei sind 206Pb, 207Pb und 208Pb radiogene Isotope, welche als Endglieder der natürlichen Zerfallsreihen von 238U, 235U und 232Th entstanden sind. 204Pb ist ein sogenanntes primordiales Isotop, welches bereits vor Entstehung der Erde vorhanden war. Aufgrund dieser Prozesse weisen Gesteine, Mineralien und Erze eine charakteristische Bleiisotopenzusammensetzung auf, die von der Ausgangskonzentration an Blei, Thorium und Uran sowie von der seit der Gesteinsgenese vergangenen Zeit abhängt. Diese Eigenschaft bleibt auch während der Bleigewinnung aus dem Erz, meist Galenit, erhalten, auch wenn das Silber vorher durch Kupellation abgetrennt wurde687. Das in Silbererzen enthaltene Blei war ein willkommenes Nebenprodukt der Erzverhüttung und wurde zur Herstellung von Bleiobjekten verwendet. Artefakte, die aus dem so gewonnenen Blei gefertigt wurden, spiegeln daher die Bleiisotopenzusammensetzung der verwendeten Rohmaterialien wider.
Aufgrund ihrer einfachen und zuverlässigen Anwendung werden Elastomere für viele Dichtungsaufgaben eingesetzt. In vielen Anwendungsbereichen, wie z.B. Verkehr, Luftfahrt und Verfahrenstechnik, können während des Einsatzes tiefe Temperaturen auftreten, bei denen die Funktionsfähigkeit der Dichtung erhalten bleiben muss. Daher ist die Untersuchung des Verhaltens von Elastomerdichtungen bei tiefen Temperaturen wichtig, um ihren Temperatureinsatzbereich nach unten abzugrenzen und dadurch einen verlässlichen Betrieb zu sichern. Ziel dieser Arbeit ist es, den sicheren Einschluss von gefährlichen Gütern unter verschiedenen Umgebungsbedingungen und über lange Zeiten zu ermöglichen bzw. die Materialauswahl entsprechend zu steuern.
Basic principles and technical realization of Auger Electron Spectroscopy (AES) are presented. Different modes of application are briefly addressed. These are spectroscopy at nanoscaled surface layers including quantitative element analysis and chemical state analysis, in-depth element analysis, imaging and element mapping. A survey on standards related to application of AES in surface chemical analysis is given.
In den Rückständen thermischer Verfahren sind bedingt durch den Verbrennungsprozess Metalle sowohl in elementarer wie auch in chemisch gebundener Form enthalten. Früher wurde Eisenschrott vor allem deshalb mit Magneten abgetrennt, weil sonst die Verwertung als Baustoff erschwert war. Nichteisen-Metalle, bei Rostasche aus einer Müllverbrennungsanlage (MVA) sind dies hauptsächlich Kupfer und Aluminium, können mit der Wirbelstromtechnik abgetrennt werden. Auf diese Weise sinken auch die Gehalte an umweltrelevanten Schwermetallen. Allerdings werden die kleinen Korngrößen und die chemische gebundenen Metallen (z.B. Oxide oder Carbonate) bisher in der Aufbereitung nicht erfasst. Der Beitrag befasst sich mit den verfahrenstechnischen Potenzialen zur Erhöhung der Metallausbeute.
Luftstaub über den Meeren - Wie historische Staubproben Wissenschaftler und Künstler inspirieren
(2013)
Langzeituntersuchungen an Metalldichtungen mit innen liegendem Federkern und doppelter Ummantelung
(2013)
In Deutschland werden in Transport- und Lagerbehältern (TLB) wärmeentwickelnde radioaktive Abfälle gegenwärtig über einen Zeitraum von bis zu 40 Jahren zwischengelagert. Aufgrund der Situation der noch nicht abgeschlossenen Endlagersuche werden hier möglicherweise Verlängerungen in Betracht zu ziehen sein. Im Deckeldichtsystem der TLB werden in der Regel Metalldichtungen vom Typ Helicoflex® eines französischen Herstellers verwendet, die aus einem innen liegenden Spiralfederkern und zwei Ummantelungen bestehen. Die Ermittlung der Fliess- und Relaxationseigenschaften der Dichtungskomponenten über den vorgesehenen langen Betriebseitraum sind vor dem Hintergrund des Erhalte eines geforderten hohen Dichtniveaus ein wichtiger Untersuchungsgegenstand.
Der nachfolgende Beitrag geht auf einen Vortrag zurück, der am 10.01.2012 im Rahmen des 77. Sicherheitswissenschaftlichen Kolloquiums gehalten worden ist Dieser Vortrag wie auch der nachfolgende Beitrag beruhen auf den Arbeiten einer vom Ausschuss für Betriebssicherheit (ABS) berufenen Projektgruppe, die ihre Ergebnisse am 10.12.2012 im Rahmen der 22. Sitzung des ABS abschließend vorgestellt hat. Die Projektgruppe hatte den Auftrag, für den ABS eine Methodik zu entwickeln, mit deren Hilfe das Erfordernis von besonderen Prüfungen für Arbeitsmittel i.S. der Betriebssicherheitsverordnung (BetrSichV) ermittelt werden kann.
Für die bisher der winterlichen Witterung schutzlos ausgelieferten acht Figurengruppen auf der Schlossbrücke in Berlin wurde innerhalb des vom Landesdenkmalamt Berlin und der Senatsverwaltung für Stadtentwicklung initiierten Forschungsprojektes geprüft, ob und welcher Typ einer Einhausung in der Lage ist, die schädlichen Umwelteinflüsse zu reduzieren. Um den hohen konservatorischen, bauphysikalischen, bautechnischen, künstlerischen und stadträumlichen Anforderungen gerecht zu werden und mögliche Lösungen erstmalig umfassend auf ihre Effektivität zu untersuchen, war die Zusammenarbeit von Denkmalpflegern, Restauratoren, Architekten, Ingenieuren, Geologen, Materialwissenschaftlern und Bauphysikern notwendig. Das durch die Deutsche Bundesstiftung Umwelt (DBU) geförderte Projekt zielte darauf ab, in einem Modellvorhaben mit seinen Partnern, der Technischen Universität Dresden (Institut für Bauklimatik), der Universität Göttingen (Abt. Strukturgeologie und Geodynamik), der Bundesanstalt für Materialforschung und -prüfung (Fachgruppe 7.1, Baustoffe) und unter Beteiligung der Universität der Künste (Fachbereich Konstruktives Entwerfen und Tragwerkslehre) in Berlin, eine innovative und nachhaltige Wintereinhausungskonstruktion auf die besondere Situation der Marmorskulpturen der Schlossbrücke anzupassen und ihre Wirksamkeit zu überprüfen.
Glossary Biomineralization A process by which living organisms produce minerals. - Chernobyl Ukrainian city site of the largest nuclear power plant accident in history. - Cut-off-wall Underground structure designed to prevent the flow of water. - DART Deep aquifer remediation tool. - Diffusion Movement of ions and molecules from places of higher concentration to places of lower concentration. - Electrochemical remediation Remediation technologies comprising electrochemical transport and transformation methods. - Electrokinetic screens Structures used to prevent radionuclides from diffusing from the polluted area into the environment. - Electromigration Transport of charged ions or ion complexes in solution. - Electroosmosis Movement of liquid relative to a charged stationary surface, - Electrophoresis Movement of charged particles relative to a stationary fluid. - Enhanced electrochemical remediation Use of pH control and additives to improve removal efficiency. - EURT East Urals Radioactive Trail area contaminated due to a nuclear accident. - Natural attenuation (NA) Remediation relying entirely on natural processes. - Permeable reactive barriers Passive in situ treatment zones of reactive material that degrades or immobilizes contaminants as groundwater flows through it. - Phytoremediation Soil remediation using living plants and their associated microorganisms. - Radionuclide or radioisotope An atom with an unstable nucleus whose excess energy is available to be imparted to a newly-created radiation particle within the nucleus or to an atomic electron. - Total material requirement (TMR) Sum of domestic and imported primary natural resources and their hidden flows.
Active thermography is sensitive to inhomogeneities at and below the surface of objects investigated. Thus, it should be useful for detecting plaster delaminations on concrete. In this paper, the results of field and laboratory investigations into plaster-covered concrete were compared. For evaluating the bonding state of the plaster it is not sufficient to study only the thermal contrasts at the surface of the investigated objects. The experimental results suggest that the overall thermal behaviour has to be considered.
As shown recently, the quantification of damage in historic masonry structures is possible by using active thermography. In this paper, a case study is presented concerning systematic studies of the determination of damage size and prognosis of damage increase inside a sandstone column by using different approaches of active thermography. Various heating sources as well as impulse and periodic heating have been compared. Reproducible investigations in regular time intervals for structural monitoring are possible.
Tribologie des céramiques
(2013)
Les ceramiques modernes sont differentes des ceramiques traditionnelles (carrelage, materiaux de construction, porcelaine); on les distingue par des adjectifs tels que « techniques », « industrielles » ou « thermomecaniques ». Les ceramiques industrielles sont caracterisees par leur caractere refractaire marque et de grandes duretes. Leur mediocre tenacite explique leur sensibilite ä la presence de defauts, d'oü leur reputation d'etre peu resistantes et cassantes.
Les ceramiques techniques sont utilisees pour:
• leurs proprietes electriques ou dielectriques;
• leurs proprietes magnetiques et de supraconducteurs ;
• leurs proprietes optiques;
• leurs proprietes chimiques;
• leurs proprietes biologiques;
• leurs proprietes nucleaires.
En outre, eiles sont employees pour leurs proprietes mecaniques, thermomecaniques et tribologiques, ainsi que pour leur tenue face ä la corrosion. Nous allons nous concentrer sur leur comportement tribologique.
Due to their extreme high hydrogen contents, high molecular weight (HMW-) and ultra-high molecular weight (UHMW-) polyethylene (PE) are a comprehensible choice as neutron radiation shielding material in casks for storage and transport of radioactive materials. But as a direct consequence of inserting radioactive material in such casks, gamma radiation occurs. Hence, the impact of gamma radiation on the molecular structure of polyethylene has to be taken into consideration. Consequently, PE has to withstand any type of gamma radiation induced degradation affecting safety relevant aspects in order to be applicable for long term neutron radiation shielding purposes during the whole storage period (in Germany, for instance, up to 40 years). The scope of our investigation comprises an estimation of the impact of gamma radiation and temperature on the molecular and supra molecular structure of the two types of PE used as neutron radiation shielding cask components. A further point which is worth exploring is to what extent these changes are detectable by conventional analysis methods. Therefore, thermoanalytical measurements were performed such as differential scanning calorimetry (DSC), thermo mechanical analysis (TMA), dynamic mechanical analysis (DMA), and thermo gravimetric analysis (TGA). Additionally optical and weighing methods were applied. With those methods it is possible to detect structural changes in polyethylene induced by exposure to gamma radiation. The observed amounts of changes of the irradiated material are not safety relevant for the application of polyethylene as neutron radiation shielding material; moreover, some properties actually improve via irradiation.
Cina
(2013)
ESEM-EDX analyses for the characterisation and reproduction of nineteenth-century gold tesserae
(2012)
Environmental scanning electron microscopy with energy dispersive X-ray analysis (ESEM-EDX) is a versatile working tool for the examination of gold tesserae as well as for the selection of suitable materials for their reproduction. In this paper, the ESEM-EDX analyses of original gold tesserae and their damage types are presented. These analytical results form the basis for further calculations of glass properties and experiments. These calculated values enable the determination of the relevant glass properties and allow us to choose the appropriate type of modern glass for further experiments. Subsequent experiments convert this knowledge into practice. By comparing the analytical results from the original glasses and the replicas the accuracy and precision will be shown.
Pulse thermography is a non-destructive testing method based on infrared imaging of transient thermal patterns. Heating the surface of the structure under test for a short period of time generates a non-stationary temperature distribution and thus a thermal contrast between the defect and the sound material. In modern NDT, a quantitative characterization of hidden imperfections in materials is desired. In particular, defect depth and shape are of interest. The reconstruction of the defect from thermography data is a nonlinear inverse problem, and ill-posed. We propose an algorithm for the identification of subsurface defects based on the travel time of the reflected thermal pulse. Our work extends results by Lugin and Netzelmann, taking lateral thermal flows directly into account while retrieving the defect depth. This requires significantly less computational work. Quantitative information about the defect shape and depth is obtained. Application of our method to both thermography data generated by a finite element simulation and experimental heating of PVC test specimens with different defects yields good reconstruction of the actual defects.
Digital image analysis
(2011)
Comparatiye digital analysis was performed on the five moon drawings from the New York copy of the Sidereus Nuncius and the copperplate etchings printed in the Graz and Florence copies. The sequences of figures for the drawings on pages 8r, 9v and lOv demonstrate the process of digitally enhancing the black material on the drawings, isolating that material and then overlaying it on the etchings. Using an image editing program (Image Pro® Plus by Media Cybernetics) the black material on the drawings and the letterpress-printed text were isolated and segmented from the brown drawing media. As shown in Figs. 4, 6 and 8, the isolation was possible and the black material clearly overlaps the demarcation line in the drawings. To compare the drawn and printed images of each moon, the images were laid on top of each other with Adobe Photoshop® (Adobe Systems). In these images, the printed text was used for alignment and scale. By decreasing the opacity of the image on top, the lines of each image were compared. This technique revealed an almost one-to-one correlation between the demarcation line in the drawing (as indicated by the black material) and that on the etching. In each case, the similarities and concurrences by far outnumbered the minor deviations in line. One precondition of this work was that all the photographs be at the same angle, plane-parallel, so that the drawings could be compared with the etchings. A slight aberration in the plane could distort the geometry of the illustrations. Rectification of the image plane was carried out by means of the program metigo® MAP 2.2 (Fokus GmbH Leipzig). To validate the method, photographs from the same detail of the New York copy taken with different photographic cameras and different Parameters were rectified with metigo® MAP and compared in Adobe Photoshop®. The overlay of these photographs shows a good correlation in the layout of the lettering and moon figures with only small aberrations. The distribution of the black material on the drawings can be followed as clearly in the rectified photographs as in the unrectified photographs, the information is the same.
Within the project COORAL (German acronym for 'CO2 purity for capture and storage') first studies on piping steels exposed to CO2 and artificial brine with high chloride concentration have been carried out. Corrosion behavior of martensitic Cr13 steel (1.4034) was investigated in a corrosive environment (artificial saline brine, T = 60 °C, CO2-flow rate 3 – 5 L/h, atmospheric pressure, exposure times from 1 h up to 14 days) using electrochemical and metallographic techniques. Different corrosion kinetics were observed as a function of exposure times and chloride concentration in the artificial brine. In CO2-saturated brine pitting corrosion was observed at free corrosion potential, whereas in the brine without addition of NaCl a stable passive layer built up. Predictions about corrosion mechanism are made and verified by means of surface analytical techniques.
Dynamic-mechanical material analysis as a basis for a general performance exploration complemented by system testing under superimposed climatic and mechanical loading seems to be a promising interdependent test approach addressing the performance behavior of construction sealants under more realistic conditions. With this contribution an attempt is made to adapt dynamic-mechanical material analysis, which has been already successfully validated for different construction types of expansion joint systems in road and bridge engineering, to the field of construction sealants for building façades. Test results from dynamic-mechanical material analysis characterizing the temperature-dependent, deformation-dependent, and frequency-dependent behavior of structural sealant materials are presented and exemplarily discussed for three different sealant products. An attempt is made to address unknown material characteristics in the multi-dimensional loading matrix representing practical use conditions. Furthermore, the applicability of this test approach and its various complex test modes for the exploration of technological performance and especially estimation of fatigue behavior is verified in several examples. Based on this fundamental material exploration, it is planned to complement the dynamic-mechanical assessment methodology by means of system tests on a section of a structural glazing system subjected to a simplified but superimposed loading function. The technical fundamentals and the procedure proposed to develop an adequate system test mode are introduced. The motivation for these investigations is to identify the actual mechanical system behavior under load combinations and for specimens that both closer resemble reality. The objective is to achieve a consistent and interdependent test program complementary to the existing methodology. Finally, the study is meant to initiate further progress toward a performance-related methodology which considers the design, specification, material, and system selection.
In der kunstreichen Stadt Augsburg wurde das Hinterglasgewerbe Ende des 17. Jahrhunderts eingefiihrt, setzte sich mit dem Hinterglasmaler Johann Wolfgang Baumgartner (1702 Ebbs, b. Kufstein -1761 Augsburg) in den Jahren 1733 bis 1746 fort, erfuhr ab der Mitte des 18. Jahrhunderts, besonders zwischen 17S0 und 1800, eine wahre Blüte, um Anfang des 19. Jahrhunderts langsam zu erlöschen. Augsburgs Hinterglasproduktion setzte im Vergleich zu benachbarten Städten spät ein, machte sich aber durch den umfänglichen Fernhandel einen großen Namen und die Stadt wurde zum führenden Zentrum des Handwerks. Mit seiner überzeugenden Umsetzung der grafischen Vorlagen in hintermalte Bildwerke hat Baumgartner einen entscheidenden Impuls zur Ansiedlung der Hinterglasmalerei gegeben.
The widely held incorrect belief in the self-contained underwater breathing apparatus (SCUBA) diving community, that oxygen-enriched gas mixtures, so-called NITROX, with an oxygen content of up to 40 vol. % can be considered as regular air, has already been refuted in many papers. Now, another dangerous practice has drawn the attention. In a market study, more than 60 representative SCUBA cylinder valves were examined. Sales offices claim that all of those valves can be used for oxygen-enriched gas mixtures. The fact is that some of these cylinder valves are for air use only. By exchanging the nonmetallic materials and applying additional cleaning procedures, these air valves become so-called “oxygen clean.” Then, the valves are on sale for oxygen-enriched service. This procedure is dangerous because the labeling pretends a pseudo-safety. All of the 60 SCUBA cylinder valves were tested applying the standardized oxygen pressure surge tester at BAM. As suspected, many of the cylinder valves are not burn-out safe. In addition, different test results were received for actual new valves, for so-called new but temporarily stored valves, and for used valves. This paper reveals another dangerous practice and wants to alert the SCUBA diving community.
Hyphenated techniques
(2012)
Supramolecular interactions are vital processes in many chemical sensors, biochemical assays, and other analytical detection schemes. On the background of the current, rapidly developing, and constantly changing requirements for (bio)analytical techniques, the classical molecular host is increasingly overburdened to accomplish a specific analytical task with the desired selectivity and sensitivity. Instead, other signaling strategies have to be conceived that overcome the limits in signal output, dynamic range, or compound targeting, which are imminent to various traditional methods. A very promising approach is the combination of concepts of supramolecular chemistry with nanostructured or nanoscopic inorganic materials, that is, the development of hybrid sensor materials. Such hybrids often lead to improved functionality and enhanced performance, and the present chapter discusses the contributory features in relation to the major aspects, which are related to the enhanced coordination by the preorganization of binding sites, signal amplification by the preorganization on surfaces, aggregation‐mediated signaling, surface‐modification‐based signaling, the tuning of selectivity through polarity and size, and gated signaling.
Much has been published over the last years on finding the best (consensus) reference value (RV) for a given set of laboratory data attained in inter- or key comparisons (the latter with a specific view to the CIPM MRA). However, the discussion is ongoing. Except cases where real reference values are available from other sources, the quality of the (consensus value is of major importance in proficiency testing, method Validation, or reference material certification.
A distribution-free, self-consistent RV estimation approach has been developed which is based on the single criterion of participant's compatibility, at the cost of adjusted uncertainties. The final result is a fully compatible data set with minimum Overall variance, and adjusted uncertainties for those values reported which had to be made compatible with the (key comparison) reference value.
Any outlier discussion becomes obsolete, including considerations concerning different degrees of robustness of the various location and .dispersion estimators available. The penalty for "badly" performing laboratories is a large attributed uncertainty which forces them to either improve the measurement or adjust (i.e. reduce) their performance Claims. The evaluation algorithm is described. An example from a CCQM comparison is given, and consequences for the performance Claims of the participants discussed.