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Die Ressourcen der Erde sind nicht nur endlich, sondern werden zudem ineffizient genutzt. Mit dem im Dezember 2015 verabschiedeten Aktionsplan zur Kreislaufwirtschaft fördert die Europäische Kommission den Übergang zur stärker kreislauforientierten Wirtschaft. So werden Anforderungen an Reparaturfähigkeit, Lebensdauer und Recyclingfähigkeit von Produkten zukünftig in der Ökodesign-Richtlinie gesetzt. Die Ökodesign-Richtlinie regelt momentan die Energieeffizienz von energieverbrauchsrelevanten Produkten. Um Anforderungen an den nachhaltigen Einsatz von Ressourcen zu formulieren, fehlen jedoch Normen und Definitionen. Diese Normen werden Momentan geschaffen - erst danach können gesetzliche Anforderungen folgerichtig umgesetzt werden.
The adsorption of water in one-dimensional channels in porous aluminophosphate material AlPO4-5 has been studied by a combination of gravimetric Analysis techniques, neutron and X-ray diffraction and Neutron spectroscopy. Molecular structure of AlPO4-5 consists of 12-membered rings of alternating, corner-sharing AlO4 and PO4 tetrahedra connected by oxygen bridges into sheets in the (a, b) plane. The sheets are connected by oxygen bridges along the c crystal axis and form onedimensional channels of which the largest, formed by the 12-membered rings, have a van der Waals Diameter of about 8.3 Å. Gradually increasing the amount of adsorbed water we could follow the evolution of the confined water mobility in a systematic way and identify the molecular mechanism of water adsorption. We focused particularly on the range of low and medium relative pressures up to p/p0=0.32, where a Change from a hydrophobic behavior to a steep, capillary condensation like water intake has been observed. At the Initial adsorption stages water occupies positions close to the pore walls causing the contraction of channels in the (a, b) plane and the prolongation of the channels along c axis in AlPO4-5. With the progressing intake water molecules form chains along the main channels. The cooperative interactions between water molecules lead to the onset of phonon-like cooperative modes and, surprisingly, to the increase of diffusive-like motion, which slow down only in the final adsorption stages when AlPO4-5 channels are completely filled.
Seit September 2015 gelten für neue Heizgeräte EU-weit einheitliche Mindeststandards: Heizkessel müssen mindestens den Standard der Brennwerttechnik erreichen (ausgenommen sind B1-Gasetagenheizungen für Mehrfachbelegung). Wird ein alter Wärmeerzeuger ausgetauscht, muss daher stets der Schornstein für die Abgasabführung im Überdruck geeignet sein und gegen Kondensat ertüchtigt werden, also feuchtebeständig sein. Handelt es sich um eine mehrfach belegte Abgasanlage der Arten C4, C8 oder B3, sind alle am Schornsteinstrang angeschlossenen Gasgeräte betroffen. In einem Expertengremium des DVGW wurden Handlungsempfehlungen erarbeitet. Einige Lösungsansätze vermeiden einen sofortigen Austausch aller Geräte an einem gemeinsamen Schornsteinstrang.
Seit September 2015 gelten für neue Heizgeräte EU-weit einheitliche Mindeststandards: Heizkessel müssen mindestens den Standard der Brennwerttechnik erreichen (ausgenommen sind B1-Gasetagenheizungen für Mehrfachbelegung). Wird ein alter Wärmeerzeuger ausgetauscht, muss daher stets der Schornstein für die Abgasabführung im Überdruck geeignet sein und gegen Kondensat ertüchtigt werden, also feuchtebeständig sein. Handelt es sich um eine mehrfach belegte Abgasanlage der Arten C4, C8 oder B3, sind alle am Schornsteinstrang angeschlossenen Gasgeräte betroffen. In einem Expertengremium des DVGW wurden Handlungsempfehlungen erarbeitet. Einige Lösungsansätze vermeiden einen sofortigen Austausch aller Geräte an einem gemeinsamen Schornsteinstrang.
Standardization research is a fairly new and is a still-evolving field of research, with possibly major practical ramifications. This article presents a summary of the authors’ subjective views of the most pressing research topics in the field. These include, among others, standards (e.g. incorporation of ethical issues), the potential impact of standards, the corporate management of standardization and legal issues like Intellectual Property Rights (IPR). In addition, gaps have been identified with a respect to a basic understanding of standardization, suggesting a need for better education in the field.
Highly ordered and highly cooperative water with properties of both solid and liquid states has been observed by means of neutron scattering in hydrophobic one-dimensional channels with van der Waals diameter of 0.78 nm. We have found that in the initial stages of adsorption water molecules occupy niches close to pore walls, followed later by the filling of the central pore area. Intensified by confinement, intermolecular water interactions lead to the formation of well-ordered hydrogen-bonded water chains and to the onset of cooperative vibrations. On the other hand, the same intermolecular interactions lead to two relaxation processes, the faster of which is the spontaneous position exchange between two water molecules placed 3.2-4 A from each other. Self-diffusion in an axial pore direction is the result of those spontaneous random exchanges and is substantially slower than the self-diffusion in bulk water.
Cost analysis of screening methods to find non-compliant models using the example of tumble dryers
(2019)
The European energy label was established to reduce energy consumption in Europe. All classes and values on the energy label are stated by the supplier. The task of market surveillance is to ensure correct labels and to validate their values through compliance tests. However, this can only be done for a small fraction of all models on the market, since physical tests are expensive. Screening methods can be used to narrow down the number of critical products before compliance tests are done to decrease the costs of finding non-compliant models.
This study shows a mathematical approach to analyze the cost benefits of screening methods to find non-compliant models. Furthermore, the analysis presented has been applied to 18 screening methods for tumble dryers. The performance test for tumble dryers consists of seven test runs. All screening methods evaluated are composed of a reduced number of test runs. The most efficient screening method reduces the surveillance costs by 40 %.
Minimum energy performance standards and labels are commonly used tools to reduce the household energy use thus mitigating greenhouse gas emissions. However, the technical foundation for minimum energy performance standards and labels are test procedures for rating and testing of appliances. To de- termine the seasonal cooling performance of air conditioners, the current test standards require fixing of the compressor speed of the units to achieve steady-state conditions; this way of operation, how- ever, differs from real-life use. To make the seasonal cooling performance testing better reflect the real use conditions, this study proposes a compensation method which can be conducted independently from manufacturer data and still allows modulation of the tested units. Our results show that the tested units behave differently under part-load conditions, which results in a lower energy efficiency rating for some of the tested devices.
Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 "Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea". This was a follow-on comparison from CCQM-K95 which was completed in 2014.
The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %.
Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography.
Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 "Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile".
Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz[a]anthracene (BaA), benzo[a]pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %.
Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pKow < −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography.