The Impact of Isotopic Concentration,Impurities, and Cell Aging on the Water Triple-Point Temperature

In 2005, the National Institutes of Standards and Technology (NIST) and Fluke’s Hart Scientific Division initiated a study to validate the isotopic correction algorithm applied to the realization temperature of triple point of water (TPW) cells. Additionally, the study quantified the impact of water sample impurities on the TPW cell realization temperature. For this study, eight TPW cells containing water of the same nominal isotopic concentration as Vienna Standard Mean Ocean Water (VSMOW) were used. Five of the cells were manufactured with fused-quartz envelopes and the remaining three with borosilicate envelopes. One TPW cell of each type was uniquely designed so that water samples could be periodically removed to analyze the isotopic composition and to monitor any changes in water purity with time and thereby correlate changes in composition with changes in realization temperature. The borosilicate TPW cells gave an average drift of −13 μK · yr⁻¹ and the more stable fused-quartz TPW cells gave an average drift of −2 μK · yr⁻¹.     

Isotopic Composition of Water Used in Triple-Point Cells

Isotopic analysis of the water used in KRISS triple point of water (TPW) cells was performed by three separate laboratories. The δD and δ ¹⁸O isotopic composition of six ampoules, made from two TPW cells, were analyzed by isotope ratio mass spectrometers. The analysis data showed that δD and δ ¹⁸O were − 62.17‰ and − 9.41‰ for the KRISS-2002-Jan cell, and − 36.42‰ and − 4.08‰ for the KRISS-2005-Jun cell. The temperature deviation of the triple point of water for these cells calculated from Kiyosawa’s data and the definition of the TPW were + 45.07μK for the KRISS-2002-Jan cell, and + 25.49μK for the KRISS-2005-Jun cell. The KRISS TPW temperature was + 92μK higher than the CCT-K7 KCRV after correcting for the deviation of the isotopic composition from Vienna Standard Mean Ocean Water.     

Implementing a New Group of TPW Cells as National Standard: Impact on Calibration Services

The definition of the kelvin is based on the triple-point temperature of highly pure water having the isotopic composition of ocean water (more specifically, the isotopic composition is equivalent to that of VSMOW). Belgian national metrology realizes the triple point of water (TPW) as the mean of temperatures measured in three sealed cells. In order to take into account the isotopic composition effect on TPW temperature, the ensemble of cells was replaced in 2006. Three new cells, with isotopic analysis of the contained water, were bought from different manufacturers. The new group of cells was compared to the old TPW national realization in order to quantify the effect of moving towards a new reference. Two different standard thermometers were used in all the cells to take 10 daily measurements on two different ice mantles. The measured resistances were corrected for hydrostatic head, self-heating, and isotopic composition (when available) before calculating the difference. A difference of about 87 μK was found between the old and the new national references. This difference is transferred to customers’ thermometers and cells through calibrations, and the change has to be documented in each new calibration certificate. An additional consequence of the new ensemble cell implementation is the significant reduction in the spread of deviations of individual cells from the mean temperature. The maximum difference between two cells of the ensemble is 96 μK for the old reference cells and 46 μK for the new reference cells corrected for isotopic composition effects.     

Isotopic Correction of Water-Triple-Point Cells at NMIJ

The twenty-one participating laboratories in the international key comparison of water-triple-point cells (CCT-K7) can be classified into three groups: two laboratories that corrected the effect of the isotopic composition of water, four laboratories that had information on the isotopic composition but did not correct the effect, and the remaining laboratories that had no information. There were significant differences in the realized national standard for the triple point of water (TPW) between those laboratories that applied the isotopic correction and those that did not. The isotopic correction is now considered essential for the triple point of water. Since the National Metrology Institute of Japan (NMIJ) did not apply the isotopic correction and estimated large uncertainties at the time of the CCT-K7 comparison, we subsequently developed new cells for the TPW to improve the reliability and to reduce the uncertainty of the realization as a national reference. The isotopic compositions of seven cells were analyzed, and a chemical impurity analysis of one cell was performed. The good consistency among seven cells was shown in the results obtained when the isotopic correction was applied to the realized temperatures measured experimentally. The expanded uncertainty of the new national reference of NMIJ is estimated to be 49 μK (k = 2), and as a result of this improvement, the expanded uncertainty for calibrating a water-triple-point cell is 80 μK. The previous reference of NMIJ, reported in CCT-K7 to have an expanded uncertainty of 302 μK, is 42 μK lower than the new one. The new reference value is within the uncertainty of the previous national reference, and the new uncertainty is completely covered by the previous uncertainty. Furthermore, the new reference of NMIJ shows good agreement with the national references of the six laboratories able to apply isotopic corrects to their results for CCT-K7. These facts confirm the validity and the linkage to the CCT-K7 of both the previous and the new national references of NMIJ.     

高准确度水三相点容器

水三相点的高精度复现及准确测量是保证国际温标ITS-90实施的关键。水三相点容器内高纯水的同位素组成会影响复现的水三相点温度值。为了提高水三相点复现水平,减小氢氧同位素的影响,研制了带有氢氧同位素分析的石英及硼硅玻璃高准确度水三相点容器。为了评价容器的性能,开展了硼硅玻璃和石英水三相点容器的比对。实验结果表明:同位素修正前,石英玻璃和硼硅玻璃水三相点容器复现的水三相点在0.058mK范围内一致;同位素修正之后,容器之间的差异在0.017mK范围内一致。采用高准确度水三相点容器复现水三相点的扩展不确定度为0.066mK(k=2)。     

Isotope and Impurity Content in Water Triple-Point Cells Manufactured at NMi VSL

The isotopic and impurity content of 15 water triple-point cells, manufactured at NMi VSL in the past three years, were investigated. The isotopic analyses were performed on water specimens sampled at three different stages of the manufacturing process. This allowed us to separate and quantify the influence of the source water and of the manufacturing process (distillation, degassing) on the final isotopic composition of the water in the cells. Inductively coupled plasma mass spectrometry (ICPMS) was conducted on selected water samples to investigate the potential contamination of the source water during the manufacturing process, and to evaluate the impact of impurities on the water triple-point temperature. The temperature differences among the manufactured cells were measured, and correlations between the observed differences and the results of isotope and chemical analysis were studied.     

Realization of the Triple Point of Water in Metallic Sealed Cells at the LNE-INM/CNAM: A Progress Report

A miniature metallic cell for the water triple point (TPW, temperature 273.16 K) was developed for capsule-type thermometer calibrations for realizations with adiabatic calorimetry techniques. The LNE-INM/Cnam previously developed a copper cell for the water triple point and the techniques for cleaning, filling, and sealing. On the basis of previous work, a new copper cell prototype for the TPW was developed and filled at the LNE-INM/Cnam. Measurements were performed using an appropriate calorimeter and a comparison block containing several thermometers. Preliminary results show a scatter of the temperatures measured at the phase transition of the order of 0.2 mK when measurements are repeated over a short-term period (1 month). A positive drift in the phase transition temperature of about 30μK·month⁻¹ was observed over several months. Studies are in progress to improve the cell, to reduce the reproducibility uncertainty to less than 0.1 mK and to have a phase transition with better temporal stability.     

Progress Towards the Determination of the Relationship of Triple-Point Temperature versus Isotopic Composition of Neon

Following the finalization of the work performed to establish the triple-point temperature versus isotopic composition relationship for protium (Metrologia 42, 171 (2005)) adopted into the ITS-90 definition by the International Committee for Weights and Measures (CIPM) in 2005, and a preliminary exploration of the variability in the triple-point temperature of neon gas samples arising from differences in isotopic composition (Anal. Chem. 77, 5076 (2005)), this article reports further progress toward the determination of a similar comprehensive relationship for neon, to be included in a future revision of the Technical Annexe to the ‘mise en pratique’ of the kelvin. This progress article mainly concerns a set of gas samples used for the neon triple-point measurements during CCT-K2, and subsequently, others for which the isotopic compositions were recently measured. Recent high accuracy measurements of the corresponding thermal data are now available for many of these samples, but not yet for all of them.     

Isotopic Effects on the Temperature of the Triple Point of Water

An investigation into the effects of isotopic composition on the triple point temperature of water has been carried out at the National Institute of Metrology (NIM), China, since redefinition of the kelvin with respect to Vienna Standard Mean Ocean Water (V-SMOW) was officially proposed by the Consultative Committee for Thermometry (CCT) in 2005. In this paper, a comparison of four cells with isotopic analyses and relevant results corrected for isotopic composition, employing the isotope correction algorithm recommended by the CCT, is described. The results indicate that, after application of the corrections, the maximum temperature difference between the cells drops from 0.10 mK to 0.02 mK and that these cells are in good agreement within 0.02 mK. Also, temperature deviations arising from isotopic variations fall in the range from −55.9 μK to + 40.7 μK. We consider that the distillation temperature and degassing time of the production procedure lead to isotopic variations.     

金属外壳水三相点容器

水三相点是ITS-90国际温标中最重要的定义固定点,其复现不确定度是传递到整个温标的.目前,通常采用不同的冻制方法在硼硅玻璃或石英水三相点容器内冻制均匀的冰套来复现水三相点.冻制过程中,由于在水三相点容器内生成冰桥,会造成容器的破裂.为了解决此难题,研制了金属外壳水三相点容器,利用高纯水自发相变原理,在液体槽内自动冻制...     

Industrial applications of the dolomite from Potamia, Thassos Island, N. Aegean Sea, Greece

The examined dolomite is composed of 98% of mineral dolomite and 2% of calcite. Other silicates (i.e. quartz) exist only in trace amounts. This dolomite presents intense orange luminescence colour, indicating the absence of impurities and thus high purity. Its chemical composition is: CaO=32.9%, MgO=20.2%, CO₂=46.7%, others=0.14% and its isotopic composition is δ¹⁸O=−3.10‰ and δ¹³C=+3.40‰. These values indicate that this dolomite has been formed mainly by recrystallisation of pre-existing limestone with simultaneous or subsequent partial substitution of CaCO₃ by MgCO₂ (dolomitisation). The data of its most important physicochemical properties are: water absorption=0.2%, water dissolution=0.17%, surface area=1.10 m²/g, pH=10.0, oil absorption=24 ml/100 g and brightness=97%. These data satisfy almost all the quality demands for use of its wastes after processing for the production of many industrial products. The most significant fields of use of the dolomite from Potamia, except its main world-wide demand as decorative stone, may be: as filler, whitening, and extender product in many paper, paint, and rubber industries; in addition, it can be used for the production of fertilisers.

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Résumé La dolomite etudiée se compose de 98% de dolomite minérale et de 2% de calcite. Les autres silicates (tel que le quartz) existent seulement en traces. Cette dolomite présente en luminescence une couleur intense orange, indiquant l'absence d'impuretés et de ce fait une grande pureté. Sa composition chimique est: CaO=32,9%, MgO=20,2%, CO₂=46,7%, autres=0,14%; sa composition isotopique est: δ¹⁸O=−3,10‰ et δ¹³C=+3,40‰. Ces valeurs indiquent que cette dolomite a été formée surtout par recristallisation d'un calcaire pré-existant avec substitution simultanée ou substitution partielle subséquente du CaCO₃ par MgCO₃ (dolomitisation). Les données les plus importantes concernant les propriétés physico-chimiques sont: l'absorption de l'eau=0,2%, la dissolution de l'eau=0,17%, la surface spécifique=1,10 m²/g, le pH=10,0, l'absorption d'huile=24 ml/100 g et la brillance=97%. Ces données satisfont presque toutes les exigences de qualité quant à l'usage de ses déchets, après traitement pour la fabrication d'un certain nombre des produits industriels. Les usages les plus significatifs de la dolomite de Potamia, exception faite de sa demande universelle en tant que pierre décorative, sont les suivants: elle peut servir de filler, de produit de blanchissement ou de blanc de charge dans beaucoup d'industries (papier, peinture et caoutchouc). En plus, elle peut être utilisée pour la production d'engrais.

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Editorial Note Aristotle University of Thessaloniki is a RILEM Associate Member.     

An analysis of the error in measuring the field of the maximum magnetic permeability of steels

The error δ in measuring the parameters of the field Hμ _m of the maximum magnetic permeability μ _m of steels is estimated. It is established that δ is 5–10 times greater than the error of ±5% in measuring μ _m . It is shown that not all the reference data on μ _m and Hμ _m of steels are reliable. The inadvisability of using Hμ_m in magnetic structural analysis is demonstrated.     

Analysis of the Comparison of TPW Realizations in Europe in Light of CCT Recommendation 2 (CI-2005)

Three comparisons of different triple-point-of-water (TPW) realizations in Europe have been organized under the auspices of EUROMET (EUROMET Projects 278, 549, and 714). Thirty European national metrology institutes were involved in these three comparisons that took place from 1994 to 2005. The aim of these successive projects was to assess the uncertainties associated with the practical realization of the triple point of water in Europe. Fifty-four TPW local cells were compared to a traveling standard cell (ref 679) circulated with an isothermal enclosure. The same equipment was used for the three projects, and LNE-INM regularly checked the stability of the TPW standard cell. Recently, LNE-INM has devoted efforts to bring the French standard at the triple point of water into close agreement with CIPM Recommendation 2 (CI-2005). The isotopic fractionation between water and ice when the cell is in use was experimentally studied. Several new TPW cells delivered by the manufacturer with water samples were added to our batch of reference cells. A French laboratory analyzed the isotopic compositions of these samples. These actions allow the French national definition of temperature at the triple point of water to be changed. A new temperature was associated with TPW cell 679 in agreement with the CIPM recommendation. In this presentation, the latest TPW cell measurements carried out by LNE-INM are presented. The results from EUROMET Projects 278, 549, and 714 are investigated in light of these changes.     

Automated Realization of the Triple Point of Water Using the Mush Method

In order to investigate mechanisms of phase transitions of supercooled water in a triple-point-of-water (TPW) cell when a mush method was used to create an ice mantle, an automated apparatus using small TPW cells was developed to obtain the TPW. In this article, the design principle, the apparatus, and the procedure for an automated formation of ice mantles in small TPW cells are described. Supercooled water in small TPW cells spontaneously transformed into uniform metastable dendritic crystals throughout the cells at supercoolings ranging from 5.85 °C to 8.77 °C and then changed into stable hexagonal closed-packed cellular crystals, forming an outer ice mantle from the outside inward. Some pertinent explanations based on thermodynamic solidification theory were used to describe the phase transition process in the mush method. In addition, the experimental results indicated that the realized temperatures of water in the small TPW cells were in good agreement within 0.1 mK approximately 6 h after the initial spontaneous crystallization had occurred. Finally, the small TPW cells (s/n 008 and s/n 001) were directly compared with a conventional TPW cell (s/n NIM-1-211); the temperature differences between the small TPW cells and the regular TPW cell were less than 0.21 mK.     

An Experimental Investigation of the Long-Term Stability of Triple-Point-of-Water Cells

Contamination of triple-point-of-water (TPW) cells by the chemical components of the borosilicate glass that contains the water is now widely recognized as the principal contributor to long-term drift of the cell temperature. To add to the available experimental data, a comparison of 24 TPW cells of various ages (from 10 years to 59 years), manufacturers (NRC, Jarrett, Isotech), and materials (borosilicate glass and fused quartz) was undertaken in 2013. Twelve cells from this group were compared to one another in 1997. By comparing the current inter-cell temperature differences to those determined 16 years earlier, it was found that some cells have remained stable, others have become colder (as might be expected from ongoing dissolution of the glass), and one or two show an apparent increase in temperature that seems anomalous. Also included among the 24 cells are five cells of borosilicate glass and five of fused quartz that were purchased 10 years ago. By comparing the relative temperature differences among this group of borosilcate and fused-quartz-encapsulated cells to the values obtained when they were last compared 6 years ago, it was found that the average temperature of the borosilcate group of cells decreases by \(-6\,\upmu \mathrm{K}\,{\cdot }\,\mathrm{year}^{-1}\,({\pm }2\,\upmu \mathrm{K}\,{\cdot }\,\mathrm{year}^{-1})\) , in reasonable agreement with an average drift of \(-4\,\upmu \mathrm{K}\,{\cdot }\,\mathrm{year}^{-1}\) suggested 12 years ago. It was concluded that fused quartz is the superior container for TPW cells.     

CCT-K7水三相点容器国际关键比对

在国际互认框架内,国家计量标准的国际等效性是通过国际计量委员会（CIPM）的咨询委员会组织的一系列国际关键比对来确定的。温度咨询委员会（CCT）委托国际计量局（BIPM）作为主导实验室组织了由20个国家实验室参加的CCT-K7水三相点容器国际关键比对。比对结果表明：这些国家基准水三相点值在0．171mK范围内一致。此外,为了减小国家实验室复现水三相点的系统差,需要进一步研究同位素组成对水三相点温度的影响以及同位素修正。     

Preparation of eutectics by directional solidification of quaternary melts

This paper presents a theoretical analysis of quasi-equilibrium directional solidification of a quaternary melt. We consider the variation in the composition of phases in each portion of the sample and changes in phase composition for various types of phase reactions. The results indicate that the melt trajectory during directional solidification may belong only to those phase diagram elements corresponding to the crystallization of binary, ternary, or quaternary eutectics or single-phase crystallization regions. Using the directional solidification of a melt with the composition (at %) Cu 29.37, Ni 17.72, Fe 5.91, and S 47.00, we obtained a sample consisting of zones with different phase compositions: [Ni _z (Fe,Cu)_{1 − z} ]S_{1 ± δ} single-phase zone, [Ni _z (Fe,Cu)_{1 − z} ]S_{1 ± δ} + Cu_{5 ± x} Fe_{1 ± x} S₄ binary eutectic mixture, and [Ni _z (Fe,Cu)_{1 − z} ]S_{1 ± δ} + Cu_{5 ± x} Fe_{1 ± x} S₄ + (Ni _z Fe_{1 − z} )S₂ ternary eutectic mixture. In going from one zone to another, new phases appear and the average composition of the sample changes sharply, whereas the compositions of the melt and solid solution present in neighboring zones vary continuously. These results are consistent with theoretical concepts.     

Thermodynamic principles of the synthesis of CdTe,ZnTe, and CdZnTe solid solutions

Results of thermodynamic investigations of the P-T-X phase equilibria in Cd-Te, Zn-Te and Cd-Zn-Te systems carried out by measuring total vapor pressure in the 1–760 Torr (0.13–101 kPa) range at temperatures up to ∼1370 K are systematized. Concentration boundaries of the existence of intermediate phases with the compositions CdTe_1±δ, ZnTe_1±δ, and Cd_{1 − x} Zn _x Te_1±δ (x = 0.05, 0.10, 0.15) are established. Vapor compositions in crystal-vapor equilibria are determined and isopleths of partial pressures for the CdTe_1±δ and Cd_{1 − x} ZnxTe_1±δ (x = 0.05, 0.10, 0.15) systems are calculated. Being presented in an analytical form, the thermodynamic data provide a basis for targeted synthesis of the indicated compounds.     

Impedance-spectroscopy analysis of oriented and mercerized bamboo fiber-reinforced epoxy composite

Bamboo fiber-reinforced epoxy composites were fabricated with untreated and alkali treated bamboo fibers. Dielectric, electric modulus, ac, and dc conductivity studies were carried out to rationalize the dielectric behavior of bamboo/epoxy composites. Composites of two fiber orientation parallel and perpendicular to the electric field were prepared. The dielectric behavior and electric modulus spectra of the composites were characterized using standard impedance analyzer. Dielectric properties were analyzed as a function of frequency (95 Hz–2 MHz) for temperatures in the range from 30 to 180 °C. Real part of dielectric constant (ε′), conductivity, and dielectric dissipation factor (tan δ) of 0° oriented bamboo/epoxy composites were higher than that of 90° oriented composites. Conductivity activation energy, tan δ, ε′, and volume resistivity decreased with increase in frequency at all the temperatures under study. Mercerization reduces the water absorption in bamboo fibers and thus improves corresponding dielectric properties of composites. Relaxation times 39.80 μs and 258.5 μs for 0° and 90° oriented bamboo/epoxy composites were calculated respectively from the relaxation peaks observed in electric modulus spectra at 180 °C.     

Asymptotic estimation of the threshold power and anti-Stokes combination frequencies of stimulated temperature scattering in solid-state microcavities for the optical range

Asymptotic estimates of the threshold power and anti-Stokes combination frequencies of stimulated temperature scattering (STS) have been obtained for spherical fused-quartz microcavities for the optical range. A three-mode regime of interaction of the temperature and electromagnetic modes of the whispering gallery type is considered. It is shown that a threshold STS power of is on the order of 50 μ W for quartz spheres with a radius of 40 μ m at a pumping radiation wavelength of 840 nm. Microcavities featuring the whispering gallery modes are promising elements for the construction of resonance bolometers and microlasers.