Detection and evaluation of partial discharges (PD) is important for quality assurance and diagnosis ofelectrical insulation systems. With increasing use of DC voltages in electrical transmission and distributionsystems, the field of PD under DC voltage stress needs to be further investigated.CIGRE Working Group D1.63 was approved for start in May 2015, where available knowledge and experiencein particular concerning the field distribution in insulation systems used in DC voltage systems, and thephysical processes of the PD phenomena under DC voltage stress should be reviewed. In order of guidingto meaningful procedures for DC PD measurements of HV equipment thorough understanding of i) thedifferences of PD behaviour between AC and DC with respect to the physical process and ii) influencingfactors of operating conditions (as e.g. polarization, temperature etc.) of different insulation systems underDC stress and respective effects on PD phenomena had to be examined.

In this deliverable from the SeCoHeat project, profits that can be made with 1 MWh of electricity production capacity on existing ancillary service markets are evaluated in 2020 and 2021. Profits are evaluated for four different marginal production costs corresponding to the following fuels for a CHP power plant: waste (assumed fuel price: 0 kr/MWh), recycled wood (10 kr/MWh), wood chips (20 kr/MWh) and wood pellets (30 kr/MWh). The results show that except for wood chips and wood pellets in 2020, the most profitable ancillary service markets are FFR (fast-frequency response) and aFRR down (automatic frequency restoration reserves for down-regulation). The reasons are that (1) producers don’t have to withhold capacity from the day-ahead market when their participate in these two markets and (2) producers get compensated for the capacity reserved for the ancillary service markets. For wood chips, the FFR market was the most profitable in 2020, followed by the mFRR down market (manual frequency restoration reserves for down-regulation). The reason for the mFRR down market to be more profitable than the aFRR down market for this fuel is that the profits from mFRR down depend on the avoided fuel costs, which are higher for wood chips than for waste and recycled wood. In 2021, all prices started increasing significantly, which decreased the relative profitability of the mFRR down compared to other markets. For wood pellets, the mFRR down market was also the second most profitable market in 2020, for the same reasons. The most profitable one in 2020 was the mFRR up market (manual frequency restoration reserves for up-regulation). The reason is that the higher fuel price of these two fuels entails low participation in the day-ahead market. Therefore, withholding capacity from the day-ahead market to be able to participate on the mFRR up market brings additional profits. In 2021, however, day-ahead prices started increasing significantly (a trend that continued into 2022) and the mFRR up market became the least profitable market for these two fuels. The profit evaluation performed in this deliverable is purely economic. It does not include the sector coupling to the heat sector (which entails limitation of the available electricity production capacity but also a possibility to store heat if storage is available) nor does it include other technical limitations such as ramp rates. These aspects will be considered in follow-up work in this project. This report has been compiled within the scope of the project SeCoHeat - Sector coupling of district heating with the electricity system: profitability and operation. The project is financed by the Research and Development Foundation of Göteborg Energi.

To address the emerging challenges in electricity distribution networks, various solutions have been proposed such as alternative tariff design, local flexibility markets (LFMs), bilateral contracts, and local energy markets (LEMs). However, choosing a suitable solution is not straightforward due to multi-dimensional complexity of the challenges which may vary under different circumstances. This paper proposes a toolbox for qualitative and quantitative comparison of the different solutions. The toolbox includes a multi-dimensional analytical framework and a flexible modeling and demonstration platform for conducting quantitative comparison studies. Four solutions i.e. LFM, LEM, cost-reflective tariffs, and bilateral contracts are compared qualitatively using the framework and a real demonstration example of an LFM design is presented utilizing the modeling platform. The toolbox can facilitate research on the local grid challenges and contribute to finding a suitable solution from a multi-dimensional perspective.

In order to demonstrate the equivalence in calibration of mass standards among National Metrology Institutes (NMIs) of EURAMET this key comparison (KC) on 1 kg stainless steel mass standards has been carried out under the auspices of EURAMET. The comparison was undertaken with reference to the International Prototype Kilogram (IPK) as the definition of the unit of mass. The overall result shows good consistency among the participants. 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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In this study the maritime communication system VDES (VHF Data Exchange System) is proposed to distribute Network-RTK (NRTK) correction data to shipborne GNSS receivers in fairways, port areas, or inland water ways. The transport layer used for transmission of VDES messages (related to the standard IEC61162-450) is the UDP multicast protocol. This makes it possible to transmit the RTCM packages from the VDES transponder to the shipborne GNSS receivers as a UDP payload without any additional formatting. In order to minimize the impact on the overall VDES data capacity in a local service area, NRTK correction data shall at most occupy a single VDES slot with a net capacity of 650 bytes denoted Link ID 19. This is the fastest link in VDES. Update rates may vary but are preferably at 1Hz. However, depending on the number of visible satellites NRTK correction data size changes instantly and the data rate can therefore sometimes be in excess of 1000 byte/s per reference station to be distributed. In order to comply with the VDES requirements, the Lantmäteriet Adjustment Solution (LAS) for GNSS correction data adjustment was developed and is presented in this paper. The responsibility of this solution is to produce a correction data stream that complies with the bandwidth limitation of 650 bytes/s. To provide corrections for a potentially large number of users, dissemination is done by broadcasting corrections for a grid of VRSs. The proposed solution has therefore also the capability to combine several correction data streams from several Virtual Reference Stations (VRSs) into one single correction data stream. To reduce the required data rate, the LAS has the ability to filter streamed GNSS correction data in the RTCM3 MSM format constellation-wise, satellite-wise, and signal-wise. The objective is to achieve optimal performance in terms of accuracy for the ship's differential positioning solution, while at the same time adhering to constraints that might locally apply for individual transmitters. For this paper LAS was configured to interface with the SWEPOS to provide reference data to static and kinematic testing scenarios. The results presented here were obtained using RTK post-processing with RTKLib for a combination of GPS and Galileo multi-frequency observations. Results indicated that LAS solution can achieve robust positioning performance with decimeter-level accuracy which meet the requirements expected for the navigation safety at Sea. Adapted-NRTK correction data (LAS data) via VDES has the potential to be part of a world-wide standard VDES application for all vessels sailing under SOLAS and for ships that voluntarily uses VDES in the near future (inland, yachts, navies, leisure).

For the solar energy industry to increase its competitiveness, there is a global drive to lower the cost of solar-generated electricity. Photovoltaic (PV) module assembly is material-demanding, and the cover glass constitutes a significant proportion of the cost. Currently, 3-mm-thick glass is the predominant cover material for PV modules, accounting for 10%–25% of the total cost. Here, we review the state-of-the-art of cover glasses for PV modules and present our recent results for improvement of the glass. These improvements were demonstrated in terms of mechanical, chemical and optical properties by optimizing the glass composition, including addition of novel dopants, to produce cover glasses that can provide (i) enhanced UV protection of polymeric PV module components, potentially increasing module service lifetimes; (ii) re-emission of a proportion of the absorbed UV photon energy as visible photons capable of being absorbed by the solar cells, thereby increasing PV module efficiencies and (iii) successful laboratory-scale demonstration of proof of concept, with increases of 1%–6% in Isc and 1%–8% in Ipm. Improvements in both chemical and crack resistance of the cover glass were also achieved through modest chemical reformulation, highlighting what may be achievable within existing manufacturing technology constraints. © 2020 The Authors.

A EURAMET key comparison of the national pressure standards in the range 0.7 MPa to 7.0 MPa of gas gauge pressure was carried out. The circulation of the transfer standard began in November 2011 and lasted until November 2016. The measurand of the comparison was the effective area of the piston-cylinder assembly determined by gauge pressure measurements in the range from 0.7 MPa to 7.0 MPa. As the comparison reference value, the weighted mean of the results of the laboratories with primary pressure standards was used. With this reference value, all the participants who delivered the results demonstrated equivalence respective to the reference value within expanded uncertainties (k = 2) on all the range. The results of this comparison were linked to CCM key comparison CCM.P-K1.c. Also in relation to the reference values of CCM.P-K1.c, all participants demonstrated agreement within expanded uncertainties (k = 2) at all pressure points.

A secondary measurement standard filling the gap between the available static and dynamic standards was developed. The standard utilizes a quick-opening valve and bursting diaphragms to generate step-like pressures with amplitude of few kilopascals to 10 MPa and with frequency content from 10-2 Hz to 800 Hz. An important design feature of the developed standard lies in the usage of aluminium diaphragms, allowing short rise times and high frequency content. The standard is based on two reference sensors, calibrated statically and dynamically. The reference sensors showed a linear dynamic response in the intermediate frequency range and was in good agreement with the static calibration results. Therefore, extrapolation of shock tube results was implemented. To demonstrate the capabilities of the developed standard, three pressure measurement systems were characterized, and their respective dynamic response was calculated. The results show that the developed standard can provide calibration information that are not currently available.

In this paper, we introduce a robust method for dynamic characterization of pressure measuring systems used in time-varying pressure applications. The dynamic response of the pressure measuring systems in terms of sensitivity and phase as a function of frequency at various amplitudes of the measurand can be provided. The shock tube which is the candidate primary standard for dynamic pressure calibration at the National Laboratory for pressure, Sweden, was used to realize the dynamic pressure. The shock tube setup used in this study can realize reference pressure with amplitudes up to 1.7 MPa in the frequency range from below a kilohertz up to a megahertz. The amplitude of the realized step pressure was calculated using the Rankine–Hugoniot step relations. In addition, the accurate time of arrival of the generated shock at the device under test (DUT) was measured using an optical probe based on shadowgraphy. The optical detector has a response time in nanosecond time scale which is several orders of magnitude faster than the response time of any pressure measuring system. Hereby, the latency between physical stimuli and response of the DUT can be measured. By the knowledge of the amplitude and the accurate time of arrival of the reference step pressure, the transfer function of the DUT can be calculated and presented in Bode diagrams of sensitivity and phase response versus frequency. The uncertainty in sensitivity and phase measurements was estimated. The information provided by this work is useful for developing reliable models of dynamic pressure measuring system and provide accurate information about their dynamic response. That in turn will contribute to establish a traceability chain for dynamic pressure calibration.

Accurate dynamic pressure measurements are increasingly important. While traceability is lacking, several National Metrology Institutes (NMIs) and calibration laboratories are currently establishing calibration capacities. Shock tubes generating pressure steps with rise times below 1 µs are highly suitable as standards for dynamic pressures in gas. In this work, we present the results from applying a fast-opening valve (FOV) to a shock tube designed for dynamic pressure measurements. We compare the performance of the shock tube when operated with conventional single and double diaphragms and when operated using an FOV. Different aspects are addressed: shock-wave formation, repeatability in amplitude of the realized pressure steps, the assessment of the required driver pressure for realizing nominal pressure steps, and economy. The results show that using the FOV has many advantages compared to the diaphragm: better repeatability, eight times faster to operate, and enables automation of the test sequences.

Power system resilience is an overarching concept covering the whole spectrum of the power system, from design and investment decisions to planning, operations, maintenance and asset management functions. Flexibility concerns the power system's ability to manage changes, with flexibility features able to improve the resilience characteristics of the system, provided that they are integrated into grid planning, in defence plans, and evaluated adequately in the energy market design. An analysis of ongoing worldwide initiatives provides relevant insight into ongoing worldwide initiatives. They provide relevant insight into how flexibility can support resilience, showing the prominence and potential values that can be unlocked, with potentially some low-hanging fruits to start. This paper introduces four innovative concepts: Alternative grid development, system integrity protection schemes, the next level of flexibility and LINK holistic approach to flexibility for resilience as solutions contributing to improving future power systems' resilience.

In underdoped cuprate high-Tc superconductors, various local orders and symmetry-breaking states, in addition to superconductivity, reside in the CuO2 planes. The confinement of the CuO2 planes can therefore play a fundamental role in modifying the hierarchy between the various orders and their intertwining with superconductivity. Here we present the growth of a-axis oriented YBa2Cu3O7-δ films, spanning the whole underdoped side of the phase diagram. In these samples, the CuO2 planes are confined by the film thickness, effectively forming unit-cell-thick nanoribbons. The unidirectional confinement at the nanoscale enhances the in-plane anisotropy of the films. By x-ray diffraction and resistance vs temperature measurements, we have discovered the suppression of the orthorhombic-to-tetragonal transition at low dopings, and a very high anisotropy of the normal state resistance in the b-c plane, the latter being connected to a weak coupling between adjacent CuO2 nanoribbons. These findings show that the samples we have grown represent a novel system, different from the bulk, where future experiments can possibly shed light on the rich and mysterious physics occurring within the CuO2 planes.

The ISO 14687-2 standard sets requirements for the purity of the hydrogen that is delivered at refuelling stations. These specifications cover a wide range of impurities and include challenging measurements, mainly due to the very low levels of the required detection limits and the need for "total" measurements (total hydrocarbons, total sulphur compounds, halogenated compounds). Most of the compounds belonging to the species are organic. Thermal desorption often coupled with gas chromatography is a common speciation method used to determine the content of organic impurities. However, no existing sorbent tubes are sufficiently universal to trap all possible impurities; depending on the sorbents and the sampling volume, some compounds may irreversibly adsorb or may break through. It is therefore necessary to evaluate sorbents for the compounds targeted at the level required. In this study, the suitability of sorbent tubes for trapping organic impurities in hydrogen was investigated. Suitable sorbents were selected based on a literature review of suitable sorbent materials. Short-term stability studies for compounds among hydrocarbons, halogenated compounds and sulphurcompounds on the selected sorbents have then been performed for storage periods of two weeks since this is the period typically required to complete the collection, transport and analysis of hydrogen samples. The study clearly shows that the method is promising for total species, even through the results show that not all of the compounds belonging to the three total species to be analysed when performing hydrogen purity analysis can be quantified on one unique sorbent. A multibed sorbent consisting of Tenax TA (weak), Carboxen 1003 (medium), Carbograph 1 (strong) is shown to be a versatile sorbent suitable for the three "total species"; only a few compounds from each family would need to be analysed using other analytical methods. This method proposed here for total species will not only provide a sum of concentrations, but also an identification of which compound(s) is/are actually present in the hydrogen.

The study presents an optimised method to correct flow rates measured with a LFE flowmeter pre-set on methane while used for gas mixtures of unknown composition at the time of the measurement. The method requires the correction of the flow rate using a factor based on the viscosity of the gas mixtures once the composition is accurately known. The method has several different possible applications inclusive for the sampling of biogas and biomethane onto sorbent tubes for conformity assessment for the determination of siloxanes, terpenes and VOC in general. Five models for the calculation of the viscosity of the gas mixtures were compared and the models were used for ten binary mixtures and four multi-component mixtures. The results of the evaluation of the different models showed that the correction method using the viscosity of the mixtures calculated with the model of Reichenberg and Carr showed the smallest biases for binary mixtures. For multi-component mixtures, the best results were obtained when using the models of Lucas and Carr. 

Standards ISO14687 and EN17124 set stringent limits for numerous gaseous impurities and particulates that may damage the fuel cell system in a hydrogen vehicle, as it is highly sensitive to the presence of even very low levels of impurities. However, performing the whole set of analyses is both technically challenging and time-consuming for any laboratory and will require a combination of several analytical techniques or instruments. In this study, we discussed the selection of analytical techniques for hydrogen purity testing in order to optimize the CAPEX (capital expenditure) and OPEX (operational expenditure), while ensuring the quality of the results and the compliance of the analytical methods with ISO21087. Among the individual impurities to be analysed in ISO14687, spectroscopy techniques are suitable for ammonia, carbon dioxide, carbon monoxide, formaldehyde, formic acid, oxygen and water. Spectroscopy techniques are even suitable for some impurities belonging to the three total species such as hydrogen sulphide, hydrogen chloride and methane. However, helium and argon, which are monoatomic, do not exhibit response in the infrared region. Therefore, any spectroscopic analysis method must be completed by another method in order to simultaneously analyse all individual gaseous impurities from ISO14687. In this study, we constructed and demonstrated the feasibility of an instrument composed of a gas chromatograph having three columns (two packed columns and a PLOT (Porous Layer Open Tubular) column and two detectors (FID and TCD) coupled in parallel to two OFCEAS instruments using reference gas mixtures. Finally, we also proposed an extended configuration that will allow performing the whole set of analyses for gaseous species from ISO14687

Vehicle gas is often compressed to about 200 bar at the refueling station prior to charging to the vehicle's tank. If a high amount of oil is carried over to the gas, it may cause damage to the vehicles; it is therefore necessary to accurately measure oil carryover. In this paper, three analytical methods for accurate quantification of the oil content are presented whereby two methods are based on gas chromatography and one on FTIR. To better evaluate the level of complexity of the matrix, 10 different compressor oils in use at different refueling stations were initially collected and analysed with GC and FTIR to identify their analytical traces. The GC traces could be divided into three different profiles: oils exhibiting some well resolved peaks, oils exhibiting globally unresolved peaks with some dominant peaks on top of the hump and oils exhibiting globally unresolved peaks. After selection of three oils; one oil from each type, the three methods were evaluated with regards to the detection and quantification limits, the working range, precision, trueness and robustness. The evaluation of the three measurement methods demonstrated that any of these three methods presented were suitable for the quantification of compressor oil for samples. The FTIR method and the GC/MS method both resulted in measurement uncertainties close to 20% rel. while the GC/FID method resulted in a higher measurement uncertainty (U = 30% rel.).

Renewable gases, hydrogen and biomethane can be used for the same applications as natural gas: to heat homes, power vehicles and generate electricity. They have the potential to contribute to the decarbonisation of the gas grid. Hydrogen blending with existing natural gas pipelines is also proposed as a means to increase the performance of renewable energy systems. Carbon capture and storage (CCS) and carbon capture and utilisation (CCU) technologies can be an answer to the global challenge of significantly reducing greenhouse gas emissions. Due to production methods, these gases typically contain species in trace amounts that can negatively impact the equipment they come into contact with or pipelines when injected into the gas grid. It is therefore necessary to ensure proper (and stable) gas quality that meets the requirements set out in the relevant standards. The gas quality standards require the collection and transport of a representative gas sample from the point of use to the analytical laboratory; i.e., no compounds may be added to or removed from the gas during sampling and transport. To obtain a representative sample, many challenges must be overcome. The biggest challenge is material compatibility and managing adsorption risks in the sampling systems (sampling line and sampling vessels). However, other challenges arise from the need for flow measurement with non-pure gases or from the nature of the matrix. Currently, there are no conclusive results of short-term stability measurements carried out under gas purity conditions (suitable pressure, matrix, appropriate concentrations, simultaneous presence of several species). © 2022, The Author(s).

In this study, we evaluated the performances of a custom-built optical feedback cavity enhanced absorption spectroscopy (OFCEAS) instrument for the determination of the composition of energy gases, focusing on methane and carbon dioxide as main components, and carbon monoxide as impurities, in comparison with the well-established, validated, and traceable gas chromatographic method. A total of 115 real sample gases collected in biogas plants or landfills were analyzed using with both techniques over a period of 12 months. The comparison of the techniques showed that the virtual model which allows the measurement, needs to be optimized using real samples of varied compositions. The OFCEAS measurement technique was found to be capable of measuring both the main components and a trace component in different matrices; to within a 2% measurement uncertainty (higher than the gas chromatograph/thermal conductivity detector (GC/TCD) method). The OFCEAS method exhibits a very fast response, does not require daily calibration, and can be implemented online. The agreements between the OFCEAS technique and the GC/TCD method show that the drift of the OFCEAS instruments remains acceptable in the long term as long as no change is made to the virtual model. Matrix effects were observed, and those need to be taken into consideration when analyzing different types of samples. © 2023 The Author(s). Published by IOP Publishing Ltd.

To enable the chemical industries in Stenungsund achieve climate neutrality, large amounts of fossil-free hydrogen will be required. Producing all hydrogen through electrolysis will demand large amounts of electric power, but the current grid capacity in Stenungsund is limited, making less electricity-intensive hydrogen production solutions essential. This study investigates the technical and commercial prerequisites for a Solid Oxide Electrolysis Cell (SOEC) pilot plant in Stenungsund. It also analyzes various scenarios to understand how SOEC and ammonia cracking can complement each other from a techno-economic perspective and enhance security of supply. The interviews that were conducted to gather insights from relevant stakeholders showed that they anticipate a significant increase in future hydrogen demand, highlighting the need for scalable and cost-effective production methods. There is strong interest within the industry cluster to learn more about SOEC technology and gain practical experience through the establishment of a pilot plant. A concept for a SOEC pilot plant has been outlined in the current study including a description of the possible integration with existing infrastructure in Stenungsund. The intention with such a pilot plant is to test and gain experience from commercially available equipment of a size that is relevant for large scale hydrogen production projects. Two different plant sizes were considered, corresponding to approximately 5 MW (case 1) and 10 MW (case 2) electric power demand. There is a clear scale benefit for the larger plant which makes it the preferred choice, but the investigation showed that the CAPEX for the SOEC pilot plant is higher than initially expected. To proceed with a project, a viable business case needs to be presented. This study also examines the technical and economic synergies between SOEC and ammonia cracking, focusing on cost optimization and operational flexibility to meet the hydrogen demand of existing Borealis steam cracker plant at the site. The analysis points to that the integration of both technologies enhances security of supply and reduces costs assuming favorable long-term low-carbon ammonia supply contracts and favourable Power Purchase Agreements (PPAs). Comparing the levelized cost of hydrogen (LCOH), the study finds that SOEC offers a lower LCOH than ammonia cracking under the assumed input costs (400 €/tNH3), provided competitive PPAs are secured (45 €/MWh). The integrated system’s LCOH ranges from 3.7 to 6.5 €/kg, depending on ammonia and electricity prices, with flexible operation potentially reducing costs to 3.7–4.5 €/kg by leveraging spot market prices. Current EU regulations mandate temporal and geographical correlation for PPAs used in renewable fuel production, which complicates flexible operation aligned with the electricity market. Full-load, year-round operation achieves the lowest LCOH, though it limits peak demand response. The sensitivity analysis suggests that exporting excess hydrogen to the industrial cluster could offset costs in low full-load scenarios. In the near term, ammonia cracking can mitigate grid constraints, while future expansion of SOEC capacity, as grid capacity grows, promises further cost reductions and enhanced operational flexibility.

Gas modulation refractometry (GAMOR) is a methodology for assessment of gas refractivity, molar density, and pressure that, by a rapid gas modulation, exhibits a reduced susceptibility to various types of disturbances. Although previously demonstrated experimentally, no detailed analysis of its ability to reduce the pickup of drifts has yet been given. This work provides an explication of to what extent modulated refractometry in general, and GAMOR in particular, can reduce drifts, predominantly those of the cavity lengths, gas leakages, and outgassing. It is indicated that the methodology is insensitive to the linear parts of so-called campaign-persistent drifts and that it has a significantly reduced susceptibility to others. This makes the methodology suitable for high-accuracy assessments and out-of-laboratory applications

Gas modulation refractometry is a technique for assessment of gas refractivity, density, and pressure that, by a rapid modulation of the gas, provides a means to significantly reduce the pickup of fluctuations. Although its unique feature has previously been demonstrated, no detailed explication or analysis of this ability has yet been given. This work provides a theoretical explanation, in terms of the length of the modulation cycle, of the extent to which gas modulation can reduce the pickup of fluctuations. It is indicated that a rapid modulation can significantly reduce the influence of fluctuations with Fourier frequencies lower than the inverse of the modulation cycle length, which often are those that dominate. The predictions are confirmed experimentally

A technique for high-precision and high-accuracy assessment of both gas molar (and number) density and pressure, Gas Modulation Refractometry (GAMOR), is presented. The technique achieves its properties by assessing refractivity as a shift of a directly measurable beat frequency by use of Fabry-Perot cavity (FPC) based refractometry utilizing the Pound-Drever-Hall laser locking technique. Conventional FPC-based refractometry is, however, often limited by fluctuations and drifts of the FPC. GAMOR remedies this by an additional utilization of a gas modulation methodology, built upon a repeated filling and evacuation of the measurement cavity together with an interpolation of the empty cavity responses. The procedure has demonstrated an ability to reduce the influence of drifts in a non-temperature stabilized dual-FPC (DFPC)-based refractometry system, when assessing pressure, by more than three orders of magnitude. When applied to a DFPC system with active temperature stabilization, it has demonstrated, for assessment of pressure of N2 at 4304 Pa at room temperature, which corresponds to a gas molar density of 1.7 × 10−6 mol/cm3, a sub-0.1 ppm precision (i.e. a resolution of 0.34 mPa). It is claimed that the ability to assess gas molar density is at least as good as so far has been demonstrated for pressure (i.e. for the molar density addressed, a resolution of at least 1.2 × 10−13 mol/cm3). It has recently been argued that the methodology should be capable of providing an accuracy that is in the low ppm range. These levels of precision and accuracy are unprecedented among laser-based techniques for detection of atomic and molecular species. Since the molar polarizability of He can be calculated by ab initio quantum mechanical calculations with sub-ppm accuracy, it can also be used as a primary or semi-primary standard of both gas molar (and number) density and pressure. © 2021 The Author(s)

The transition to a clean energy future requires thorough understanding of increasingly complex interactions between conventional generation, network equipment, variable renewable generation technologies (centralised and distributed), and demand response. Secure and reliable operation under such complex interactions requires the use of more advanced power system modelling and simulation tools and techniques. Conventional tools and techniques are reaching their limits to support such paradigm shifts. This paper provides an overview of commonly used and emerging power system simulation tools and techniques. Applications of these tools ranging from real-time power system operation to long-term planning are also discussed. Various approaches to gain confidence in the accuracy and applicability of the simulation models are presented. The paper then discusses emerging trends in simulation tools and techniques primarily stemming from the transition to a power system with increased penetration of inverter-based resources as these are used in variable renewable energy technologies.

This review is a first attempt at bringing together various concepts from research on wall- and magnetically-bounded turbulent flows. Brief reviews of both fields are provided: The main similarities identified are coherent (turbulent) structures, flow generation, and transport barriers. Examples are provided and discussed.

We present the scientific motivation for future space tests of the equivalence principle, and in particular the universality of free fall, at the 10− 17 level or better. Two possible mission scenarios, one based on quantum technologies, the other on electrostatic accelerometers, that could reach that goal are briefly discussed. This publication is a White Paper written in the context of the Voyage 2050 ESA Call for White Papers. © 2021, The Author(s).

The Eco-design directive issued by the European Commission has led to requirements on efficiency of power transformers. In the case of large power transformers used in grid applications, serious problems are encountered in establishing how reliable the loss measurements are. An effort is currently ongoing within IEC to produce a documentary standard on “Rules for the determination of uncertainties in the measurement of the losses of power transformers”. An IEC standard should be clear and easy to understand by all users in the industry. Background theory and material, whilst necessary for understanding, is not required for the day-to-day application of the standard. This paper presents a more detailed background and theory on the measurement of transformer losses and how to quantify precision. The authors are all members of the IEC maintenance team working with the standard. 

We evaluated the performance of GNSS absolute antenna calibrations and its impact on accurate positioning with a new assessment method that combines inter-antenna differentials and laser tracker measurements. We thus separated the calibration method contributions from those attainable by various geometric constraints and produced corrections for the calibrations. We investigated antennas calibrated by two IGS-approved institutions and in the worst case found the calibration’s contribution to the vertical component being in excess of 1 cm on the ionosphere-free frequency combination L3. In relation to nearby objects, we gauge the 1 σ accuracies of our method to determine the antenna phase centers within ±0.38 mm on L1 and within ±0.62 mm on L3, the latter applicable to global frame determinations where atmospheric influence cannot be neglected. In addition to antenna calibration corrections, the results can be used with an equivalent tracker combination to determine the phase centers of as-installed individual receiver antennas at system critical sites to the same level without compromising the permanent installations. © 2020, The Author(s).

Background: Persons on the autism spectrum exhibit poorer body awareness than neurotypical persons. Since movement quality may be regarded as an expression of body awareness, assessment of movement quality is important. Sound assessments of measurement properties are essential if reliable decisions about body awareness interventions for persons on the autism spectrum are to be made, but there is insufficient research. Objective: To assess measurement properties of the Body Awareness Scale Movement Quality (BAS MQ) in an autism and a neurotypical reference group. Methods: Persons on the autism spectrum (n=108) and neurotypical references (n=32) were included. All were assessed with BAS MQ. Data were analyzed according to the Rasch model. Results: BAS MQ was found to have acceptable unidimensionality, supported by the fit statistics. The hierarchical ordering showed that coordination ability was the most difficult, followed by stability and relating. Response category functioning worked as intended for 19 out of 23 items. There were few difficult items, which decreased targeting. Reliability measures were good. BAS MQ discriminated between the autism and the reference groups, with the autism group exhibiting poorer movement quality, reflecting clinical observations and previous research. Conclusions: BAS MQ was found to have acceptable measurement properties, though suffering from problems with targeting item difficulty to person ability for persons on the autism spectrum. The BAS MQ may, along with experienced movement quality, contribute to clinically relevant information of persons on the autism spectrum, although we encourage refinements and further analyses to improve its measurement properties. 

AIMS: To assess the measurement properties of the Ms. Olsen test for registered nurses and assistant nurses, respectively, and suggest cut-off points between competence levels. DESIGN: Cross-sectional study. The results were analysed by implementing the Rasch Measurement Theory. METHODS: Nursing staff working in various health care settings participated (n = 757). To measure the competence of nursing staff in clinical decision-making, a 19-item scale from the Nursing Older People-Competence Evaluation Tool-the 'Ms. Olsen test'-was used. Data were collected in October 2017, 2018 and 2019. RESULTS: The Ms. Olsen test showed reasonably good measurement properties for registered nurses and assistant nurses respectively. Results show slightly better measurement properties for registered nurses than for assistant nurses. The cut-off for registered nurses, 0.62, corresponds to managing approximately two-thirds of the items while, for assistant nurses, the cut-off of 0.01 corresponds to managing approximately half of the items. CONCLUSION: The Ms. Olsen test is a short (7- to 10-min) test measuring competence in clinical decision-making among nursing staff working in older people nursing. Despite reasonably good measurement properties, this should be considered an initial validation in the development of a short test for assessing clinical decision-making among nursing staff in various health care setting. IMPACT: Several scales aiming to measure nursing competence have been developed over the last decade, but measurement properties (beyond classical test theory) are seldom evaluated, few scales concern other staff groups than registered nurses and few scales have proposed or established cut-offs for safe practice. The Ms. Olsen test is a short test of clinical decision-making that demonstrates reasonably good measurement properties. Cut-off points for registered nurses and assistant nurses were established. The Ms. Olsen test may be used to measure and evaluate competence in clinical decision-making among nursing staff working in older people nursing and educational settings.

Aim: This paper aims to report on two modifications made to improve the measurement precision of the Ms. Olsen test. Specifically, three items were added to the Ms. Olsen test and an extended scoring was applied to some items. Design: The competence assessment had a quantitative cross-sectional design comprising of test results from 111 Registered Nurses in four municipalities in South-Eastern Norway. Methods: The Rasch model was applied to evaluate the measurement properties in four versions: the Ms. Olsen test with 19 items and the same with three added items, and the Ms. Olsen test with 19 items with an expanded scoring for the original and expanded version, respectively. Results: The person separation indexes were improved from 0.50 to 0.62. Other measurement properties were not alternating between the four versions; all had shortcomings in terms of targeting (person measure means 3.02–3.87) and unidimensionality (% t-test >5% 9.01%–13.51%). Conclusion: The clinical relevance and relatively short time spent on testing makes the Ms. Olsen test a reasonable choice and a step in the right direction for assessing competence as a means of targeting continuous professional development of nurses throughout their career. Nevertheless, depending on what kind of decisions are to be made, reliability might still be too low and further development is suggested. Public Contribution: The initiative for the competence assessment came from nursing leaders in the four municipalities involved. The municipalities were represented in all stages of the research process through co-author LS, that is, design, data collection, data analysis, writing of the manuscript as well as dissemination of the results to the four municipalities. Implications for Practice: The Ms. Olsen test exemplifies a move towards objective assessments in nursing. Precise and reliable measurements are essential to support the ongoing professional development of nurses.

One application in the medical treatment at very small flow rates is the usage of an Insulin pump that delivers doses of insulin at constant cycle times for a specific basal rate as quasi-continuous insulin delivery, which is an important cornerstone in diabetes management. The calibration of these basal rates are performed by either gravimetric or optical methods, which have been developed within the European Metrology Program for Innovation and Research (EMPIR) Joint Research Project (JRP) 18HLT08 Metrology for drug delivery II (MeDDII). These measurement techniques are described in this paper, and an improved approach of the analytical procedure given in the standard IEC 60601-2-24:2012 for determining the discrete doses and the corresponding basal rates is discussed in detail. These improvements allow detailed follow up of dose cycle time and delivered doses as a function of time to identify some artefacts of the measurement method or malfunctioning of the insulin pump. Moreover, the calibration results of different basal rates and bolus deliveries for the gravimetric and the optical methods are also presented. Some analysis issues that should be addressed to prevent misinterpreting of the calibration results are discussed. One of the main issues is the average over a period of time which is an integer multiple of the cycle time to determine the basal rate with the analytical methods described in this paper. 

Microfluidic devices are becoming increasingly important in various fields of pharmacy, flow chemistry and healthcare. In the embedded microchannel, the flow rates, the dynamic viscosity of the transported liquids and the fluid dynamic properties play an important role. Various functional auxiliary components of microfluidic devices such as flow restrictors, valves and flow meters need to be characterised with liquids used in several microfluidic applications. However, calibration with water does not always reflect the behaviour of the liquids used in the different applications. Therefore, several National Metrology Institutes (NMI) have developed micro-pipe viscometers for traceable inline measurement of the dynamic viscosity of liquids used in flow applications as part of the EMPIR 18HLT08 MeDDII project. These micro-pipe viscometers allow the calibration of any flow device at different flow rates and the calibration of the dynamic viscosity of the liquid or liquid mixture used under actual flow conditions. The validation of the micro-pipe viscometers has been performed either with traceable reference oils or with different liquids typically administered in hospitals, such as saline and/or glucose solutions or even glycerol-water mixtures for higher dynamic viscosities. Furthermore, measurement results of a commercially available device and a technology demonstrator for the inline measurement of dynamic viscosity and density are presented in this paper. © 2022 the author(s)

För att elnätet ska fungera måste frekvensen hållas inom snäva gränser och därför handlar Svenska Kraftnät upp olika typer av stödtjänster för frekvensreglering. De senaste åren har kostnaderna för dessa tjänster ökat kraftigt, bland annat till följd av en allt högre andel intermittent elproduktion. Behoven är prognostiserade att öka ytterligare under de kommande åren. Detta har skapat ett ökat intresse för batterier och deras möjligheter att stödja elnätet. Men batterier och tillhörande kraftelektronik är kostsamt. Samtidigt finns en stor och alltjämt växande batterikapacitet i landets elbilar och med hjälp av dubbelriktad laddning, så kallad vehicle-to-grid öppnas nya möjligheter att komma åt denna potential för att på ett mer resurseffektivt sätt balansera elnätet. Projektets övergripande mål har varit att utreda hur standardisering kan användas för att påskynda och öka användandet av elbilar som resurs för flexibilitetstjänster till elnätet. Bland annat har en fallstudie genomförts av Axess Logistics anläggning i Malmö hamn och möjligheterna för att deras långtidsparkerade elbilar ska kunna leverera frekvensreglering till elnätet har studerats. Resultaten visar på att studerade standarder i stort inte utgör ett direkt hinder för användandet av elbilar för frekvensreglering men att förändringar av exempelvis ISO15118 skulle kunna öka möjligheterna att använda elbilar för att leverera frekvensreglering. Till exempel genom införande av krav på mätnoggrannhet på aktiv effekt, förkortning av tillåtna svarstider, krav på lokal frekvensmätning med god noggrannhet. För långtidsparkerade bilar vore det framförallt värdefullt att arbeta fram, och i standard beskriva, en funktion där elbilens BMS kan uppmanas av EVSE att hålla batteriet i ett tillstånd där det kan användas för att snabbt svara på en begäran om i-/urladdning. Detta så att elbilen kan vara förberedd för frekvensreglering även om den för stunden inte aktivt laddar eller matar effekt till elnätet. Detta en åtgärd som skulle kunna ha stor positiv påverkan på möjligheterna för långtidsparkerade elbilar att leverera frekvensreglering. Exemplifierande användarcykler för långtidsparkerade bilar har studerats för FCR-N och FCR-D. Resultaten visar att den förväntade cyklingen skiljer stort mellan dessa olika frekvensregleringstjänster och antyder att valet av frekvensregleringstjänst behöver studeras utifrån både förväntad ekonomi och eventuellt batterislitage. Överslagsräkningar på eventuella intäkter från deltagande i frekvensreglering har genomförts och de preliminära resultaten visar att investering av dyrare laddinfrastruktur som klarar Vehicle-to-Grid skulle kunna återbetalas inom ett år med 2022 års nivåer av ersättning för frekvensreglering. I en framtid där nya elbilar antas ha stöd för Vehicle-to-Grid har potentialen för att använda långtidsparkerade elbilar på logistikanläggningar till frekvensreglering preliminärt bedömts ligga mellan 110 och 165 MW för svenska förhållanden. Detta motsvarar ca 5-8% av den nordiska FCR-marknaden. På sikt kan också långtidsparkerade bilar hos återförsäljare, flygplatser med mera att utgöra en betydande potential.

Botkyrka kommun har under 2018-2021 bedrivit pilotprojektet Arbetsmiljö och Hälsa i Fokus i syfte att förebygga och minska korttidssjukfrånvaro och för att stödja en mer hälsofrämjande organisation. Arbetet har skett i samarbete med Sveriges Kommuner och Regioner (SKR), Sveriges Forskningsinstitut RISE samt Aino Health som varit utförare för en del av insatserna. Föreliggande rapport utvärderar projektet och är tänkt att utgöra en läranderapport som illustrerar hur arbetet utvecklats under projekttiden, och sammanfattar de lärdomar som framkommit under projektets gång. Pilotprojektet har utvecklats löpande och anpassats efter de utmaningar och lärdomar som dykt upp under projekttiden. Pandemin har påverkat projektet både i det praktiska arbetet och vad gäller den på förhand uppsatta utvärderingsmodellen. Trots det finns det goda indikationer på att arbetssätten kan medföra en positiv påverkan på sjukfrånvaro och det systematiska arbetsmiljöarbetet. Utvärderingen visar att antalet nettodagar korttidsfrånvaro minskade jämfört med referensperioden under de första 17 månaderna fram till att pandemin slog igenom mars 2020. Det går inte att veta hur korttidsfrånvaron hade utvecklats under resterande projekttid utan pandemin. Men baserat på hypotesen som föranledde projektet och erfarenheter från andra håll finns det goda skäl att anta att projektets insatser visat sig effektiva för att minska korttidssjukfrånvaron i Botkyrka. Det bedöms som sannolikt att insatsen Hälsosupport ger den relativt snabba effekt på sjukfrånvaron som kunnat skönjas. När det gäller Chefsstödet hade det varit önskvärt med en längre uppföljningsperiod för att kunna urskilja effekter. Men det finns positiva indikationer. Ett återkommande mönster är att gruppen arbetsplatser som fått stöd på arbetsplatsnivå av Chefsstödet inte haft en lika kraftig ökning i sjukfrånvaro som en följd av pandemin som övriga arbetsplatser inom samma förvaltning. Vid uppföljande mätningar av det Arbetshälsoekonomiska analysverktyget (KI- mätning) visas i genomsnitt en lägre indikerad nivå av produktionsbortfall kopplad till ohälsa. Detta kan vara tecken på att ett mer systematiskt arbetsmiljöarbete etablerats och hunnit ge viss effekt på de arbetsplatser där Chefsstödet verkat. Den ekonomiska kalkylen för projektet, som tar fasta på värdet av en korttidssjukfrånvarodag enligt Försäkringskassans beräkningsmetod, tyder på att insatserna på relativt kort sikt är självfinansierade. Det ska då beaktas att flera potentiella värden av en bättre arbetsmiljö inte tas med i kalkylen. Att kostnadsbesparingar kan realiseras så pass snabbt är ovanligt för sociala investeringar och pekar på värdet av att investera i systematiskt arbetsmiljöarbete. En utgångspunkt för arbetet är insikten att det behövs stödjande insatser på såväl individ- som organisationsnivå. Samtidigt har utmaningar med att förena dessa perspektiv i ett sammanhållet utvecklingsoch implementeringsarbete synliggjorts. Behov att utveckla kompetens i förändringsledning för att skapa ökad kapacitet i kommunens förvaltningar för ständig utveckling kvarstår.

Örnsköldsviks kommun har under 2018-2021 bedrivit pilotprojektet Arbetsmiljö och Hälsa i Fokus i syfte att förebygga och minska korttidssjukfrånvaro och för att stödja en mer hälsofrämjande organisation. Arbetet har skett i samarbete med Sveriges Kommuner och Regioner (SKR), Sveriges Forskningsinstitut RISE samt Previa som varit utförare för en del av insatserna. Föreliggande rapport utvärderar projektet och är tänkt att utgöra en läranderapport som illustrerar hur arbetet utvecklats under projekttiden, och sammanfattar de lärdomar som framkommit under projektets gång. Pilotprojektet har utvecklats löpande och anpassats efter de utmaningar och lärdomar som dykt upp under projekttiden. Pandemin har påverkat projektet både i det praktiska arbetet och vad gäller den på förhand uppsatta utvärderingsmodellen. Trots det finns det goda indikationer på att arbetssätten kan medföra en positiv påverkan på sjukfrånvaro och det systematiska arbetsmiljöarbetet. Utvärderingen visar att antalet nettodagar korttidssjukfrånvaro minskade jämfört med referensperioden under de första 16 månaderna fram till att pandemin slog igenom mars 2020. Det går inte att veta hur korttidsfrånvaron hade utvecklats under resterande projekttid utan pandemin. Men baserat på hypotesen som föranledde projektet och erfarenheter från andra håll finns det goda skäl att anta att projektets insatser visat sig effektiva för att minska korttidssjukfrånvaron i Örnsköldsvik. När det gäller insatsen Arbetsmiljöhandledare hade det varit önskvärt med en längre uppföljningsperiod för att kunna urskilja effekter både kopplat till sjukfrånvaro och för att få till ett större antal uppföljningsmätningar som underlag för att bedöma hur arbetsmiljön på berörda arbetsplatser utvecklats. Den ekonomiska kalkylen för projektet, som tar fasta på värdet av en korttidssjukfrånvarodag enligt Försäkringskassans beräkningsmetod, tyder på att insatserna på relativt kort sikt är självfinansierade. Det ska då beaktas att flera potentiella värden av en bättre arbetsmiljö inte tas med i kalkylen. Att kostnadsbesparingar kan realiseras så pass snabbt är ovanligt för sociala investeringar och pekar på värdet av att investera i systematiskt arbetsmiljöarbete. En utgångspunkt för arbetet är insikten att det behövs stödjande insatser på såväl individ- som organisationsnivå. Samtidigt har utmaningar med att förena dessa perspektiv i ett sammanhållet utvecklingsoch implementeringsarbete synliggjorts. Behov att utveckla kompetens i förändringsledning för att skapa ökad kapacitet i kommunens förvaltningar för att driva ständig utveckling kvarstår.

Sweden’s first Social Impact Bond (SIB) or, as preferred, Social Outcomes Contract (SOC), was a collaborative project between Norrköping local authority and private social investor Leksell Social Ventures (LSV) supported by the Swedish Association of Local Authorities and Regions (Mission Mental Health) and Lumell Associates. The aim was to address a social challenge – improving outcomes for youth and children placed in institutional care. After an intense period of feasibility studies and contracting negotiations, the SOC became operational in August 2016. Active work with the target group continued until first quarter 2019 and the evaluation phase was completed in February 2021. This report presents the results in terms of achieved outcomes as well as a broader perspective of learnings, for Norrköping and for the general development of social investment in Sweden. The SOC should be considered a form of social investment, where an initial cost leads to longer term social and economic benefits to society. There are many examples of social investments in Sweden where local authorities have reserved internal funding in so-called social investment funds. The Norrköping SOC was the first Swedish example of a social investment case where a private investor provided a loan to the local authority for upfront funding together with a risk sharing model connected to achieved outcomes. Norrköping and LSV agreed in the SOC that LSV would provide up to 10 million SEK (~1 MEUR) for the project. The associated risk sharing model was such that Norrköping would guarantee 40 % repayment on activity while the outstanding 60 % would be repaid if cost savings in social services would be achieved. Each SEK saved in social service costs would be divided between the parts corresponding to their financial risk (60/40) up to project break even. If the savings would be larger than project costs, LSV would be allowed a total ROI capped at 20 % conditional on improved school outcomes for the target group. The evaluation period was 24 months per individual in the target group and compared with a historic reference group. If the target group individual has lower costs over the evaluation period than its comparison group average, then this provides a positive net saving. If an individual improves when it comes to school performance over 24 months, a positive value is registered, if not, a negative value. Values are assigned from -3 to +3 following an ad hoc model designed for this project (to take into account the wide age span and different educational settings for the target group). Norrköping decided it to be outside legal scope to create a historic comparison group for school performance. Net results for costs and school performance are added for the target group and thus establishing contract outcomes. In addition to primary outcomes, the project was also monitoring mental wellbeing, substance abuse, supporting relations with family and social network and achievement of individual goals. Having a 24-month evaluation period (from when the intervention starts) turned out to be challenging with costs increasing with 7,5 million SEK. However, school performance and social outcomes were all positive. Data suggested that over time, net costs were decreasing, and the project partners agreed to extend the monitoring period to 36 months, but to do this outside of the contract. Over 36 months, the evaluation indicates reduced social service costs of 4 million SEK. The project cost is 7.5 million SEK leading to a net result of -3.5 million SEK. The result is distributed between parts so that Norrköping ends with +1 million and LSV with -4.5 million SEK. In summary, the contract did not perform in the sense that LSV was not eligible to be repaid more than the 40 % guarantee. But from a project and target group perspective, the results are quite positive, both in terms of social and school outcomes and in terms of the extended period cost savings. It can also be noticed that several hypothetically positive outcomes for the target group and for society are not included in the evaluation model. All in all, the SOC should be considered a successful social investment.

Current standards for light environments are based on technical requirements, e.g. luminance, uniformity, and illuminance, and do not necessarily describe all parts of the light experience to ensure visual comfort from a user perspective. Including experience-related requirements would most likely yield better lighting comfort. To do that, new methods for specifying and measuring the user experience are needed. This paper describes a pilot study exploring a new method to analytically assess perceived lighting properties by using a trained human panel and thus make human assessments more objective. The methodology is built on established sensory methods, where the human senses are used in product assessments, traditionally applied within e.g. the food, packaging, and car industries. An analytical panel comprising eight persons fulfilling specific selection criteria were recruited and trained to assess lighting products in a multi-sensory laboratory. The results show that the panelists were able to assess lighting by distinguishing between attributes and products. Significant differences were identified between the different luminaires, both in terms of sensory and physical properties, e.g. readability and glare. Conclusively, analytical sensory methods can be applied to lighting to assess luminaires in a non-subjective way. Physical and sensory attributes do not, however, always co-vary, which shows that data from physical and sensory measuring methods provide complementary information about light quality. This knowledge may in turn be applied in tools supporting the communication between different professions in lighting design and procurement to promote light environments that are both energy efficient and desirable from an end-user perspective.

Like everywhere else, time does not stand still for water meters. The requirements change, whether through technological progress, e.g., through the use of electronic meters, or changes in drinking water consumption. A revision of relevant normative documents is currently taking place at the international level. Against this background, various studies have been carried out in recent years and infrastructure has been built up with which the measurement behaviour of water meters can be examined more closely under real operating conditions, even at the laboratory level. This article presents the infrastructure. Furthermore, two current studies on the measurement behaviour of water meters are presented. In these studies, the effect of water quality and the effect of discrete measurements on the measurement accuracy of electronic water meters were investigated. 

The networking project AdvManuNet has been started recently to accelerate the process of establishing an European Metrology Network (EMN) on Advanced Manufacturing. EMNs are intended by EURAMET, the association of metrology institutes in Europe, to provide a sustainable structure for ongoing stakeholder interaction in different thematic areas. Advanced manufacturing has been identified by the European Commission (EC) as one of six Key Enabling Technologies (KETs) with applications in multiple industries. Various EURAMET projects have partly addressed metrology needs for advanced manufacturing. However, a high-level coordination of the metrology community is currently absent and limits the impact of metrology developments on advanced manufacturing. AdvManuNet will address these limits by establishing a single hub for stakeholder consultation, a knowledge base on research results, and a strategic agenda for research and training to push forward advanced manufacturing and related KETs and strengthen Europe's position in advanced manufacturing via the EMN. 

A comparison measurement between 10 national metrology institutes on two types of depth setting standards was conducted using mostly tactile but also two optical instruments for measurement. Three etched silicon standards with depths of 5, 20 and 50 μm and one diamond turned nickel coated copper standard with depths of 200, 600 and 900 μm were measured. The cross section of the grooves was trapezoidal. Most of the participants confirmed their CMC entries. Since many measurements had to be made, contamination of the standards and heavy wear on the standards were also observed after the comparison was completed. The wear consists of indentation marks from stylus instruments on both types of standards and as many as 70 scratch marks on the nickel coated copper artefact used. This indicates that the contact pressure of the tactile measuring devices used by some partners was too high. This can be caused by a too high probing force or a too small probing tip radius. Thus, for future comparisons the actual probing force and actual tip radius need to be measured during the comparison by the participants to assure that the recommended values (2 μm tip radius and 0.7 mN probing force) are not exceeded. The recently published German standard DIN 32567-3 "Determination of the influence of materials on the optical and tactile dimensional metrology-Part 3: Derivation of correction values for tactile measuring devices" describes methods to do both. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA)

I och med omställningen till ett energisystem med en större andel förnybar el står elmarknaden inför flera utmaningar. Traditionella kraftslag som kärnkraft är ofta styrbar, men förnybara kraftslag som vindkraft är väderberoende. En ökad mängd förnybar produktion kan därmed innebära ett ökat behov av fysisk handel närmare leveranstimmen. Intradagmarknaden är en marknad för fysisk handel mellan leveranstimmen och dagen före marknaden, där majoriteten av all handel sker. Den planerade expansionen av förnybara kraftslag är en indikation på att intradagmarknadens betydelse kommer att öka. Av den anledningen är det viktigt att de aktörer som direkt eller indirekt kan påverka eller påverkas av intradagmarknaden har en god förståelse för dess funktion. Den här rapporten beskriver intradagmarknadens funktion och roll i elhandelssystemet.

Recent developments in the electric power sector as well as in district heating and cooling systems has led to an increased interest in local energy systems and markets. In the electricity sector, this is driven by the integration of distributed resources such as solar power, electric vehicles and demand response. For district heating, sustainability and energy efficiency targets drives the development to further exploit small-scale heat sources. A closer integration of these energy carriers can also unlock potential flexibility, to the benefit of local as well as overlaying systems. In this respect, there is a need to further explore the possibilities to design local energy markets to facilitate the integration between electricity and district heating, as well as providing adequate instruments enabling flexibility. This paper therefore presents a market clearing design, based on optimization, for local energy markets incorporating multiple energy carriers and bid structures suitable for representing flexibility. The market clearing model is applied in a case study to illustrate and validate key design elements. One conclusion is that even though various elements can be added to the market clearing function, there is a challenge to interpret the results due to an increased complexity of the resulting optimization problem. 

In the framework of the ongoing EMRP Joint Research Project (JRP) ENG 60 “Metrology for LNG” (2014-2017), co-funded by the European Union, a number of metrological challenges associated with custody transfer and transport of LNG will be faced. The project consists of four technical work packages (WP), whereby the main objective is to reduce the measurement uncertainty of LNG custody transfer by a factor two. The focus in WP1 is the design and development of a traceable mid-scale calibration standard for LNG mass and volume flow. The goal is to provide traceable mass and volume flow calibrations up to 400 m3/h (180000 kg/h). In WP2, the emphasis is on the development and validation of a LNG sampling and composition measurement reference standard, consisting of sampler, vaporizer, gas standards, and gas chromatography (GC), which will be used to  test and calibrate commercially available LNG sampling and composition measurement systems. The priority in WP3 is given to the development and validation of a method for the determination of the methane number, including correlations based on the LNG composition and corrections for traces of nitrogen and higher hydrocarbons. Since physical properties and quantities play an important role in LNG custody transfer, WP4 comprises reference quality density measurements of LNG to validate and improve models for LNG density predictions, the uncertainty evaluation of enthalpy and calorific value calculations and the development of a novel cryogenic sensor for the simultaneous measurement of speed-of-sound and density. The present paper gives an overview of recently achieved objectives within the project and provides an outlook to future activities.

This paper gives an overview of the ongoing Joint Research Project (JRP) 20IND11 “Metrology infrastructure for high pressure gas and liquefied hydrogen flows” (MetHyInfra), which will ensure traceability in the hydrogen distribution chain. For this purpose, very precise nozzles with well-defined geometries have been produced. In this project, Critical Flow Venturi Nozzles (CFVNs) will be traceably calibrated for the first time with hydrogen and pressures up to 100 MPa using a Coriolis Flow Meter (CFM) as a secondary standard. A CFM has been successfully calibrated with hydrogen against a gravimetric primary standard. Equations of State (EoS) are important for the high-pressure calibration of the nozzles, but also for Computational Fluid Dynamics (CFD) simulations. With regard to CFD, a numerical model has been developed to simulate high pressure hydrogen flow in the CFVN. In a parameter study, non-ideal nozzle shapes are investigated using a shape variation parameter. New Speed of Sound (SoS) measurements were conducted at temperatures from 273 to 323 K and pressures from 1 to 100 MPa. These new data were then used to develop a new EoS for normal hydrogen, optimized for gas phase calculations. In addition to gaseous hydrogen, the project has a strong focus on liquefied hydrogen. Here a three-pronged approach allows traceable measurements. Each of the approaches presented is based on a unique flow calibration principle and relies on independent traceability schemes. The results of the project will ensure traceable measurements and thus a higher level of confidence among end users. © 2024 The Authors

In the framework of the ongoing EMPIR JRP 18HLT08 Metrology for Drug Delivery (MeDDII), a main task is to improve dosing accuracy and enable traceable measurements of volume, flow and pressure of existing drug delivery devices and in-line sensors operating, in some cases, at ultra-low flow rates. This can be achieved by developing new calibration methods and by expanding existing metrological infrastructure. The MeDDII project includes, among other issues, investigations on fast changing flow rates, physical properties of liquid mixtures and occlusion phenomena to avoid inaccurate measurement results and thus improve patient safety. This paper describes the extension of an existing measurement facility at RISE and the design and construction of a new measurement facility to be able to carry out such investigations. The new measurement facility, which is based on the dynamic gravimetric method, is unique worldwide in respect of the lowest measurable flow rate. The gravimetric measuring principle is pushed to the limits of what is feasible. Here, the smallest changes in the ambient conditions have a large influence on the measurement accuracy. The new infrastructure can be used to develop and validate novel calibration procedures for existing drug delivery devices over a wide flow rate range. The extension of the measurement facilities also enables inline measurement of the pressure and the dynamic viscosity of Newtonian liquids. For this purpose, it is ensured that all measurements are traceable to primary standards. © 2022 by the authors.

In the framework of the ongoing EMPIR JRP 16ENG01 “Metrology for Hydrogen Vehicles” a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70MPa HRS regarding mass flows (up to 3.6kgmin−1) and pressures (up to 87.5MPa). © 2020 The Authors

In the framework of the ongoing EMPIR Joint Research Project (JRP) 17IND13 Metrology for real-world domestic water metering (Metrowamet), a main task is to investigate the influence of realistic operation conditions, that is, typical water qualities (suspended particles, degree of hardness, and pH value), on the measurement accuracy. For this purpose, two representative types of cold water meters were investigated in more detail. Initially, the cold water meters were calibrated and then subjected to an accelerated wear test with water of different pH values and degrees of hardness. The accelerated wear tests were designed to reproduce the realistic use and service life of a cold water meter. Subsequently, the cold water meters were re-calibrated to assess the influence of the different water qualities on the measurement accuracy. One of the results was that the measurement accuracy of the water meters investigated was not strongly affected by the water quality. The practical realisation and the measurement results are reported in this paper. © 2021 by the authors.

When testing light-duty and heavy-duty vehicles on chassis dynamometers, as in the WLTP, or engines on engine test benches, as in the WHDC, it is required to measure the fuel consumption. In the preferable case, the measurement of the fuel consumption is carried out with suitable flow meters. These require high measurement accuracy in a wide flow range, independent of the fuel type, as the flow rate range is often very large and depends on the power range of the vehicle engines. Moreover, the fuel flow rate in the test cycles is very dynamically related to the loads. In the scope of the ongoing EMPIR Joint Research Project 20IND13 SAFEST the dynamic flow behaviour as well as the measurement accuracy of flow meters for different types of fuels are investigated. This paper presents first results from the realisation of dynamic flow profiles, and flow measurements with a Coriolis Flow Meter with different representative fuels in a wide density and viscosity range and a wide flow rate range at different fuel temperatures. © 2023 The Author(s)

In the early nineties a hot water test facility was planned and constructed for calibration and testing of volume and flow meters at the National Volume Measurement Laboratory at RISE (formerly SP Technical Research Institute of Sweden). The main feature of the test facility is the capability to measure flow in a wide temperature and flow range with very high accuracy. The objective of the project, which was initiated in 1989, was to design equipment for calibration of flow meters with stable flow and temperature conditions. After many years of international debate whether static testing is adequate to represent the later more dynamic application of domestic water meters, the EMPIR project 17IND13 Metrology for real-world domestic water metering (“Metrowamet”) was launched in 2018. The project investigates the influence of dynamic flow testing on the measurement accuracy of different types of domestic flow meters. One of the main objectives of the project is the development of infrastructure to carry out dynamic flow measurements. The existing test facility at RISE was at the time of construction one of the best hot and cold-water test facilities in the world. Due to the Metrowamet project the test facility has been upgraded to meet the needs of an infrastructure for dynamic flow investigations. The first findings from dynamic consumption profile measurements are reported in this paper. © 2021 The Authors