| 1. |
- Wang, J., et al.
(författare)
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Final report of the CCQM-K145 : Toxic and essential elements in bovine liver
- 2020
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Ingår i: Metrologia. - : IOP Publishing Ltd. - 0026-1394 .- 1681-7575. ; 57:1 A
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Tidskriftsartikel (refereegranskat)abstract
- Liver plays a major role in metabolism and acts as a source of energy for the body by storing glycogen. With the growing interest and investigation in the biological effects in recent years, it is important and necessary to develop accurate and comparable analytical methods for elements in bio-samples. It has, however, been 10 years since the tissue sample (bovine liver) of CCQM-K49 key comparison. The purpose of CCQM-K145 is to ensure the comparable and traceable measurement results for essential and toxic elements such as P, S, Zn, Mn, Ni, Mo, Sr, Cr, Co, Pb, As and Hg in bovine liver among NMIs and other designated measurement bodies worldwide. The comparison was agreed by IAWG as 6th IAWG Benchmarking Exercise with Zn and Ni as exemplary elements at the meeting in Korea in the early October 2016. The results of CCQM-K145 are expected to cover the measurement capability and support CMCs claiming for inorganic elements in the similar biological tissue materials and food samples. 30 NMIs and DIs registered in CCQM-K145. With respect to the methodology, a variety of techniques such as IDMS, ICP-OES, ICP-MS(non-ID), AAS and NAA were adopted by the participants. For Zn, Ni, Sr, Pb and Hg measurements, most participants chose ID-ICP-MS method, which showed the better performance in terms of consistency and reliability of the measurement results. In aspect of the traceability for the measurement results in CCQM-K145, most participants used their own (in house) CRMs or other NMI's CRMs to guarantee trace to SI unit. Most participants used similar matrix CRMs for quality control or method validation. Base on different statistic way to calculate the reference mass fraction values and associated uncertainties for each measurand, removal of the suspected extreme values, and discussion at the IAWG meetings, the median values are proposed as the KCRV for Zn, Ni, Mn, Mo, Cr, Pb and Hg; the arithmetic mean values are proposed as the KCRV for P, S, Sr, Co and As. In general, the performances of the majority of CCQM-K145 participants are very good, illustrating their measurement capabilities for Zn, Ni, P, S, Mn, Mo, Sr, Cr, As, Co, Pb and Hg in a complex biological tissue matrix. Bovine liver contains many kinds of nutrients and microelements, it can be regarded as a typical representative material of biological tissue and food. In CCQM-K145, the analytes involved alkali metals and transition elements, metalloids/semi-metals and non metals with a range of mass fraction from mg/g to μg/kg. CCQM-K145 also tested the ability of NMIs/DIs to determine elements that were easy to be lost and polluted, and interfered significantly. The chemical pretreatment methods of samples used in the comparison is suitable for general food and biological matrix samples. A variety of measurement methods used in the comparison represent the main instrumental technology for elemental analysis. Therefore, for supporting CMC claim, CCQM-K145 is readily applicable to measurement of more elements in a wide range of biological materials (including liquids and solids) and meat products. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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| 2. |
- Boddaert, S., et al.
(författare)
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Fire safety of BIPV : International mapping of accredited and R&D facilities in the context of codes and standards 2023
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of Task 15 of the IEA Photovoltaic Power Systems Programme is to create an enabling framework to accelerate the penetration of BIPV products in the global market of renewables, resulting in an equal playing field for BIPV products, BAPV products and regular building envelope components, respecting mandatory issues, aesthetic issues, reliability issues, and financial issues.Subtask E of Task 15 is focused on pre-normative international research on BIPV characterisation methods and activity E.3 is dedicated to fire safety of BIPV modules and installations.
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| 3. |
- Hakonen, Aron, 1970, et al.
(författare)
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Hand-Held Femtogram Detection of Hazardous Picric Acid with Hydrophobic Ag Nanopillar SERS Substrates and Mechanism of Elasto-Capillarity
- 2017
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Ingår i: ACS Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 2:2, s. 198-202
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Tidskriftsartikel (refereegranskat)abstract
- Picric acid (PA) is a severe environmental and security risk due to its unstab e, toxic, and explosive properties. It is also challenging to detect in trace amounts and in situ because of its highly acidic and anionic character. Here, we assess sensing of PA under nonlaboratory conditions using surface-enhanced Raman scattering (SERS) silver nanopillar substrates and handheld Raman spectroscopy equipment. The advancing elasto-capillarity effects are explained by molecular dynamics simulations. We obtain a SERS PA detection limit on the order of 20 ppt, corresponding attomole amounts, which together with the simple analysis methodology demonstrates that the presented approach is highly competitive for ultrasensitive analysis in the field.
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| 4. |
- Hallström, J., et al.
(författare)
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Worldwide comparison of lightning impulse voltage measuring systems at the 400-kV level
- 2007
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 56:2, s. 388-391
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Tidskriftsartikel (refereegranskat)abstract
- An international comparison of lightning and switching impulse voltage measuring systems was arranged and coordinated by the Helsinki University of Technology (MIKES-TKK), Espoo, Finland, between 1999 and 2002. The number of participants was 26, including the coordinator. This paper summarizes the results obtained by those eight National Metrology Institutes that participated in the comparison. A 400-kV transfer reference measuring system for measuring lightning impulse voltages was prepared by the coordinator. In addition, a 1-kV impulse voltage calibrator system, including calibrators for both standard lightning and switching impulses, was circulated. © 2007 IEEE.
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| 5. |
- Huang, Liming, 1993, et al.
(författare)
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Improving the performance of alkali-activated slag mortar with electro/chemically treated carbon fiber textile
- 2023
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 418
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Tidskriftsartikel (refereegranskat)abstract
- Alkali-activated slag is a widely used low-carbon binder. Incorporation of textile can mitigate the brittle weakness of alkali-activated composites. The bonding between fibers and matrix is critical for the performance of textile reinforced mortar. This paper is focused on the effect of different treatment methods on the bonding properties of carbon fiber in alkali-activated slag. The interfacial shear strength of fiber bundles in matrix was determined by the pull-out test. The flexural strength of the reinforced mortar was evaluated by a repeated bending. A scanning electron microscopy test was performed to characterize the interfacial properties of the fiber bundles. The results show that the interfacial shear strength of carbon fibers in matrix is improved by the electroplating with calcium silica slurry (CSS), impregnation in different solutions, and plasma treatments. An electroplating in CSS has the best improvement in the bonding strength with an increase by 620%. The CSS treatment increases the maximum flexural strength of CFT reinforced mortar with 22.5% and 30% at 7 and 28 d respectively, and it significantly inhibits the crack growth under the cyclic loading. This effect becomes more significant after a longer curing age. The electroplating treatment eliminates the cracks in the interface of fiber yarns. Slag reacts with the plated portlandite to strengthen the bonding between mortar and fiber bundles, so it has a better inhibiting effect on the crack growth after a longer curing. © 2023 The Authors
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| 6. |
- Hällström, J, et al.
(författare)
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International comparison of software for calculation of lightning impulse parameters based on a new processing algorithm
- 2007
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Konferensbidrag (refereegranskat)abstract
- A new algorithm has been proposed to calculate the parameters of full lightning voltage impulses. The new algorithm enables the application of the test voltage factor (also referred to as k-factor in some literatures) for calculation of the equivalent test voltage of impulses with superimposed oscillations/overshoots. The new algorithm at the same time provides a robust procedure for obtaining time parameters of the impulses from not only smooth waveforms but also waveforms with varying degrees of distortions in the front part of the impulses. These distortions include oscillations on the impulse front and overshoots in the peak region. A critical part of the new algorithm is a 4-parameter fitting procedure to obtain the base curve, which is used for calculation of the test voltage curve. Another important part of the algorithm is applying a filtering procedure in the calculation of the test voltage curve. The new algorithm was tested in different laboratories using different programming languages and different techniques for realising the fitting and filtering routines. The paper reports the results obtained from the participating laboratories using the proposed algorithm. The results obtained by the participating laboratories using existing software based on the requirement of IEC 60060-1: 1989 were also compared. It is anticipated that the results can serve as a part of the basis for a new procedure for determination of lightning impulse parameters in the revised IEC 60060-1.
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| 7. |
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| 8. |
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| 9. |
- Larzelere, W, et al.
(författare)
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MEASUREMENT OF THE INTERNAL INDUCTANCE OF IMPULSEVOLTAGE GENERATORS AND THE LIMITS OF LI FRONT TIMES
- 2017
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Konferensbidrag (refereegranskat)abstract
- The recent push to higher testing voltages for research and production tests onUHV system components rated above 800kV class has led to difficulties in achieving thestandard waveshapes as required by IEC60060 Parts 1 and 2 and other existing IEC,IEEE/ANSI and other standards. One of the limiting components in achieving themaximum capacitive loading on an impulse generator for standard lightning impulse fronttimes is the inductance of the circuit. The total inductance of the circuit is comprised ofthe internal inductance of the impulse generator and the inductance of the loop toconnect to the load. The higher the voltage class of test objects, the larger the loop,yielding more inductance that in turn, reduces the test capacitance that can be connectedand still remain inside the overshoot requirements of the standards. The internalinductance of the impulse generator is comprised of the wiring of the stages and thestage capacitor inductance and/or the inductance of the waveshaping resistors. Thispaper shows the results of methods to measure and calculate the internal inductance ofseveral impulse generators and we review the formulas for calculating the maximum loadof an impulse generator with a given internal inductance. We believe these methods givemore realistic values than adding up nameplate inductance values from an impulsegenerator. The paper also reviews the pros and cons of higher stage capacitances inimpulse generators to test larger loads that are ultimately limited by the circuit inductancevalue. The intent of this paper is to assist in the revision of future IEC and IEEE standardsfor impulse testing apparatus in the UHV range
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| 10. |
- Li, H., et al.
(författare)
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Nanotribology of hydrogels with similar stiffness but different polymer and crosslinker concentrations
- 2020
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Ingår i: Journal of Colloid and Interface Science. - : Academic Press Inc.. - 0021-9797 .- 1095-7103. ; 563, s. 347-353
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Tidskriftsartikel (refereegranskat)abstract
- Hypothesis: The stiffness has been found to regulate hydrogel performances and applications. However, the key interfacial properties of hydrogels, like friction and adhesion are not controlled by the stiffness, but are altered by the structure and composition of hydrogels, like polymer volume fraction and crosslinking degree. Experiments: Colloidal probe atomic force microscopy has been use to investigate the relationship between tribological properties (friction and adhesion) and composition of hydrogels with similar stiffness, but different polymer volume fractions and crosslinking degrees. Findings: The interfacial normal and lateral (friction) forces of hydrogels are not directly correlated to the stiffness, but altered by the hydrogel structure and composition. For normal force measurements, the adhesion increases with polymer volume fraction but decreases with crosslinking degree. For lateral force measurements, friction increases with polymer volume fraction, but decreases with crosslinking degree. In the low normal force regime, friction is mainly adhesion-controlled and increases significantly with the adhesion and polymer volume fraction. In the high normal force regime, friction is predominantly load-controlled and shows slow increase with normal force.
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