281 research outputs found

    Introduction

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    CERTIFICATION REPORT: The certification of the mass fractions of cadmium copper, manganese and nickel in dark chocolate: ERM BD512

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    This report describes the production of ERM-BD512, which is a matrix material certified for the mass fraction of cadmium, copper, manganese and nickel. This material was produced following ISO Guide 34:2009 and is certified in accordance with ISO Guide 35:2006. The CRM was produced from commercially available dark chocolate produced in Peru. About 15 kg of chocolate bars were melted, the melt was homogenised and cast into moulds to produce pellets of about 0.5 g. Between unit-homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006 [ ]. Within-unit homogeneity was quantified to determine the minimum sample intake. The certified mass fraction of Cd was obtained by measurement, using the technique of isotope dilution ICP MS. The mass fractions of Cu, Mn and Ni were obtained by an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025:2005. Technically invalid results were removed but no outliers were eliminated on statistical grounds only. Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation. The material is intended for quality control and assessment of method performance. As with any reference material, it can be used for establishing control charts or validation studies. The CRM is available in packages of 6 glass vials, each containing a single pellet of about 0.5 g, which were sealed under an atmosphere of argon. The minimum amount of sample to be used is 250 mg. The CRM was accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.JRC.F.6-Reference Material

    The certification of different mass fractions of MON-Ø4Ø32-6 in soya bean powder Certified Reference Materials ERM®-BF410ap, ERM®-BF410bp, ERM®-BF410cp, ERM®-BF410dp and ERM®-BF410ep

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    This report describes the production of a set of Certified Reference Materials (CRMs), ERM BF410ap, bp, cp, dp and ep, which are certified for their GTS 40-3-2 soya bean (unique identifier MON-Ø4Ø32-6) event mass fractions. These materials were produced following ISO Guide 34:2009 and are certified in accordance with ISO Guide 35:2006. The materials are intended for the calibration or quality control of real-time PCR measurements to identify GTS 40-3-2 soya bean and quantify its mass fraction. As with any reference material, they can also be used for establishing control charts or for carrying out validation studies. The CRMs were accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials panel.JRC.F.6-Reference Material

    Sub-basin scale dust source geomorphology detected using MODIS

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    The spatial and temporal variability of dust emissions from different surfaces in the Lake Eyre Basin, Australia is determined using MODIS data. For 2003–6 the sources of 529 dust plumes were classified: overall 37% of plumes originated in areas of aeolian deposits, 30% from alluvial deposits and floodplains and 29% from ephemeral lakes or playas. At this sub-basin scale, the relative importance of different dust source geomorphologies varied primarily in response to sediment supply and availability and was not related to aeolian transport capacity, suggesting the Lake Eyre Basin is a supply-limited system

    CERTIFICATION REPORT The certification of different mass fractions of VCO-Ø1981-5 in maize seed powder Certified Reference Materials ERM®-BF438a, ERM®-BF438b, ERM®-BF438c, ERM®-BF438d and ERM®-BF438e

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    This report describes the production of a set of Certified Reference Materials (CRMs) ERM BF438a, b, c, d and e, which are certified for their VCO-Ø1981-5 mass fractions. These materials were produced following ISO Guide 34:2009 and are certified in accordance with ISO Guide 35:2006. Genetically modified (GM) seeds of the maize event VCO-Ø1981-5 and seeds from a non-GM maize variety were milled to obtain GM and non-GM seed powders with a similar particle size distribution. Mixtures of non-GM and GM maize powder were prepared gravimetrically. The certified value was obtained from the gravimetric preparations, taking into account the genetic purity with respect to the event VCO-Ø1981-5 of the two powder materials and their water mass fractions. The certified values were confirmed by event-specific real-time PCR as an independent verification method (measurements were within the scope of accreditation to ISO/IEC 17025:2005). The uncertainties of the certified values were estimated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) [4] and include uncertainties relating to possible inhomogeneity (Section 4), instability (Section 5) and characterisation (Section 6). The materials are intended for the calibration or quality control of real-time PCR measurements to identify VCO-Ø1981-5 maize and/or quantify its mass fraction. As with any reference material, they can also be used for establishing control charts or for carrying out validation studies. The CRMs are available in glass bottles containing at least 1 g of dried maize seed powder, which were sealed under atmosphere of argon. The minimum amount of sample of the mixtures to be used and recommend for the blank and pure VCO-Ø1981-5 materials is 200 mg. The CRMs were accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.JRC.D.2-Standards for Innovation and sustainable Developmen

    CERTIFICATION REPORT: The certification of different mass fractions of Bt11 in maize powder: Certified Reference Materials: ERM®-BF412ak, ERM®-BF412bk, ERM®-BF412ck, ERM®-BF412dk and ERM®-BF412ek

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    This report describes the production of a set of Certified Reference Materials (CRMs), ERM-BF412ak, bk, ck, dk and ek, which are certified for their Bt11 maize (unique identifier SYN-BTØ11-1) event mass fractions. These materials were produced following ISO Guide 34:2009 and are certified in accordance with ISO Guide 35:2006. Genetically modified (GM) maize seeds of the Bt11 event and seeds from a non GM maize variety were milled to obtain GM and non-GM seed powders with a similar particle size distribution. Mixtures of non-GM and GM maize seed powder were prepared gravimetrically. The certified values were obtained from the gravimetric preparations, taking into account the water mass fractions of the two powder materials and the genetic purity with respect to the Bt11 maize. The certified values were confirmed by event-specific real-time PCR as an independent verification method (measurements were within the scope of accreditation to ISO/IEC 17025:2005). The uncertainties of the certified values were estimated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties relating to possible inhomogeneity (Section 4), instability (Section 5) and characterisation (Section 6). The materials are intended for the calibration or quality control of real-time PCR measurements to identify Bt11 maize and quantify its mass fraction. As with any reference material, they can also be used for establishing control charts or for carrying out validation studies. The CRMs are available in glass bottles containing at least 1 g of dried maize seed powder, sealed under an atmosphere of argon. The minimum amount of sample to be used for extraction of the DNA is 200 mg.JRC.F.6-Reference Material

    Relevance of convective turbulent dust emission (CTDE) in the Earth system

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    Convective turbulence generates localized and intermittent surface shear stress and can effectively entrain dust into the atmosphere. This mechanism is referred to as 'Convective Turbulent Dust Emission' (CTDE) and is considered as the most important form of direct aerodynamic dust entrainment. CTDE occurs predominantly at weak mean wind conditions, when the buoyancy production of atmospheric turbulence is most pronounced. CTDE is a stochastic process and does not need to involve the saltation of sand-sized grains. An improved parameterization for CTDE is presented, which represents both aerodynamic lifting and inter-particle cohesive forces as probability distributions. The dust emission scheme therefore accounts for the stochastic nature of CTDE. The scheme was evaluated against field data recorded in the Horqin Sandy Land area in China and during the Japan-Australia Dust Experiment (JADE) in Australia. Coupled to the regional model WRF/Chem, the calibrated dust emission scheme was used to assess the long-term regional contribution of CTDE to the overall dust budget for Australia. We show that a persistent background dust concentration can be generated by CTDE. The modeled dust concentrations were compared to PM10 measurements monitored by the DustWatch Australia network. An estimate on the relevance of CTDE compared to saltation bombardment at the local and regional scales is given and implications for climate are highlighted

    Drivers of Australian dust: a case study of frontal winds and dust dynamics in the lower Lake Eyre Basin

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    The roles of pre-frontal, frontal and post-frontal winds as the primary wind systems for dust entrainment and transport in Australia are well established. While the relevance of each system has been observed across different wind erosion events in central Australia, the entrainment of dust by all three winds during the passage of an individual front has not been demonstrated until now. Synoptic information, satellite aerosol and imagery, meteorological and dust concentration data are presented for a single case study erosion event in the lower Lake Eyre Basin. This event demonstrates variable dust transport in three different directions from one of the southern Hemisphere's most significant source regions, and the changing nature of the active dust pathways during the passage of a frontal system. While only a single dust event is considered, the findings show the complexity of mineral aerosol emission and transport patterns even within an individual dust outbreak. For the lower Lake Eyre Basin, this appreciation of pathway behaviour is significant for better understanding the role of aeolian inputs from the dominant Australian source to surrounding marine systems. In a wider context, the findings exhibit the detailed insights into major dust source dynamics that can be obtained from high resolution spatial and particularly temporal data, as used in combination. This work highlights the importance of adequately resolved data for the accurate determination of dust entrainment and transport patterns of major dust sources

    CERTIFICATION REPORT The certification of the mass fractions of elements in bovine liver: ERM-BB185

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    This report describes the production of ERM-BB185, which is a bovine liver material certified for the mass fraction of As, Cd, Cu, Mn, Pb, Se and Zn. This material was produced following ISO Guide 34:2009 and is certified in accordance with ISO Guide 35:2006. This CRM is produced and certified to replace the CRM BCR-185R. The CRM was produced from raw livers from cattle slaughtered in Belgium. The raw livers were cut into cubes and freeze dried. The freeze dried cubes were milled and sieved to obtain a fine powder. The powder was homogenised and afterwards checked for water content and particle size distribution. The homogenised powder was put in vials and packed in aluminised pouches. Between unit-homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. The material was characterised by an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated on statistical grounds only. Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation. The material is intended for the quality control and assessment of method performance. As with any reference material, it can be used for establishing control charts or validation studies. The CRM is available in amber glass vials containing at least 10 g of dried powder which were sealed under an atmosphere of argon and packed in aluminised pouches. The minimum amount of sample to be used is 400 mg.JRC.F.6-Reference Material

    A visibility and total suspended dust relationship

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    This study reports findings on observed visibility reductions and associated concentrations of mineral dust from a detailed Australian case study. An understanding of the relationship between visibility and dust concentration is of considerable utility for wind erosion and aeolian dust research because it allows visibility data, which are available from thousands of weather observation stations worldwide, to be converted into dust concentrations. Until now, this application of visibility data for wind erosion/dust studies has been constrained by the scarcity of direct measurements of co-incident dust concentration and visibility measurements. While dust concentrations are available from high volume air samplers, these time-averaged data cannot be directly correlated with instantaneous visibility records from meteorological observations. This study presents a new method for deriving instantaneous values of total suspended dust from time averaged (filter-based) samples, through reference to high resolution PM10 data. The development and testing of the model is presented here as well as a discussion of the derived expression in relation to other visibility-dust concentration predictive curves. The current study is significant because the visibility-dust concentration relationship produced is based on visibility observations made 10-100km from the dust sources. This distance from source makes the derived relationship appropriate for a greater number of visibility recording stations than widely-used previous relationships based on observations made directly at eroding sources. Testing of the new formula performance against observed total suspended dust concentrations demonstrates that the model predicts dust concentration relatively well (r2=0.6) from visibility. When considered alongside previous studies, the new relationship fits into the continuum of visibility-dust concentration outcomes existing for increasing distance-from-source. This highlights the important influence that distance to source has on the visibility-dust concentration relationship
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