Pure Hg Research Articles

Electrochemical Liquid‐Liquid‐Solid Growth of Ag‐In Crystals with Liquid Indium Alloy Electrodes

AbstractSynthesis of intermetallic crystals by electrodeposition of Ag from alkaline aqueous electrolytes containing AgCN onto liquid metal electrodes via an electrochemical liquid‐liquid‐solid (ec‐LLS) process has been performed. X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy were performed to identify crystalline products. Ec‐LLS experiments performed with pure liquid Hg and Ga electrodes resulted in the formation of polycrystalline Ag2Ga and Ag2Hg3. Experiments performed with In‐containing liquid metals preferentially yielded Ag9In4 and AgIn2 products with liquid Hg0.35In0.65 and Ga0.86In0.14, respectively. The product distribution with liquid Hg0.35In0.65 depended on the level of Ag supersaturation during the electrodeposition. A mechanism that accounts for the aforementioned observations is presented and discussed. This work described the formation of Ag−In intermetallic phases by the isothermal electroreduction of Ag into different liquid metal solvents via ec‐LLS. Electrodeposition of Ag into a pure Ga or pure Hg liquid metal pool yielded precisely the compounds predicted from isothermal cross‐sections of the respective binary phase diagrams. These compounds were not found when using liquid Hg or Ga containing appreciable In. The smaller enthalpy of formation for AgIn2 was consistent with its synthesis in Ga0.86In0.14. However, the observed product of Ag9In4 in Hg‐containing liquid metals could not be rationalized solely from thermodynamic factors. Instead, this observation was consistent with a kinetic pathway based on the lability of Hg‐metal bonds and nearly identical crystal structures of Ag9In4 and Ag2Hg3. Site exchange of Hg for In is consistent with our prior observations[23] of In exchange into Hg−Pd structures during Pd electrodeposition. This mechanism is not based on any direct role of electrochemistry other than aspects that dictate the operative supersaturation of the metal solute.

Does pre-operative breast MRI have an impact on surgical outcomes in high-grade DCIS?

High-grade DCIS (HG DCIS) is associated with upgrade to invasive disease but few studies evaluate the role of MRI in this subset of DCIS. This study compared surgical outcomes of females with HG DCIS on biopsy who had pre-operative MRI with those that proceeded directly to surgery. This single-centre retrospective, observational study identified patients with pure HG DCIS on pre-operative biopsy from the pathology database. Surgical outcomes, clinicopathological and radiological features were obtained for all patients. From August 2015 to February 2020, 217 patients had HG DCIS on biopsy. Pre-operative MRI was performed in 40 (MRI group) and not in 88 (No MRI group) patients. Initial mastectomy was performed in 25/40 (63%) women in the MRI group and 20/88 (23%) women in the no MRI group (p < 0.0001). No difference was observed in re-operation rate between the two groups, 15% in MRI group vs 22% in No MRI group (p = 0.4749). Mean tumour size on histology was larger in mastectomy cases in the MRI group (73.4 mm, range 6-140 mm), than the total MRI group, (58.3 mm, range 0-140 mm) or no MRI group (30.7 mm, range 0-130 mm) (p < 0.0001). Pre-operative MRI in HG DCIS is associated with higher mastectomy rates, possibly due to patient selection for MRI, as tumours on final histology were significantly larger. Fewer re-operations were observed in the MRI group although this was not significant. Breast MRI performed pre-operatively in HG DCIS is associated with higher mastectomy rates and fewer re-operation rates.

Rapid thermoscanning technique for direct analysis of mercury species in contaminated sediments: From pure compounds to real sample application

Mercury (Hg) in aquatic environments accumulates in sediments in several chemical forms, both inorganic and organic, which are often determined through time-consuming selective and sequential extraction procedures. Thermal desorption technique (pyrolysis) coupled with continuous determination by atomic absorption spectrometry (AAS) may be an easy-to-use alternative technique for the rapid identification and quantification of Hg species in the solid matrix. This technique is based on the gradual heating of a sample that releases Hg at different temperature intervals depending on its chemical form. Thus, a single Hg species that desorbs at a specific temperature may be identified via a thermogram of the sample.In this work, several commercial pure Hg compounds, natural Hg mineral species (red cinnabar, α-HgS) and one compound synthesised in the lab (α-FeOOHHg) were mixed with synthetic calcium carbonate (CaCO3), silica (SiO2) and natural matrices (silicate and carbonate marine sediments) which were then desorbed in order to determine the desorption peak temperatures corresponding to each Hg species. Moreover, possible interference caused by the matrix was also considered. The results obtained from 52 desorbed MIX samples displayed different desorption temperatures for the same Hg species depending on the matrix used. Indeed, Hg species mixed with synthetic SiO2 desorbed at a temperature lower than the same species mixed with synthetic CaCO3 with a difference of approximately 100 °C.The analytical approach was applied to selected coastal sediments from the Gulf of Trieste (Northern Adriatic Sea, Italy), contaminated by Hg from the five centuries of cinnabar (α-HgS) mining activity from Idrija (Slovenia), in order to identify the unknown Hg species. The results revealed the presence of two peaks with a distinct temperature of desorption (∼250 and 350 °C). The highest temperature corresponds to the mostly refractory red cinnabar (α-HgS) compound, whereas the lowest temperature is related to other species (e.g. β-HgS) that may also include Hg associated with more mobile and potentially bio-accessible species (e.g. α-FeOOHHg) if compared to α-HgS. This methodological approach is a rapid and cost-effective technique useful to preliminarily quantify more stable Hg species (mainly α-HgS), underlining the relevance in considering the chemical form of the element rather than merely the total concentration for simplifying the environmental management of Hg-contaminated sediments.

The Effect of Fractional Replacement of Calcium with Lanthanum on the Characteristics of HgBa2Ca2-xLaxCu3O8+δ Compound

The current work involves the study of the substitution effect of calcium instead of lanthanum on the structural and electric characteristics at room of the HgBa2Ca2-1LaxCu3O8+ δ compound with (x = 0, 0.2, 0.4, 0.6 and 0.8). The specimens were manufactured via solid status reaction process. The results of X - radiation deviation showed for all samples a tetragonal system, containing the highest proportion of the pure (Hg - 1223) stage with low percentages for the minor phases (Hg - 1212, 1201) and appearance of some impurities, and the highest phase rate for the specimen at (x = 0.4) which is equal to (84.69%) and characterized by absence of impurities. The results of the measurement of the lattice constants, (c. 1 / a) and the density of mass shows that a sample with (x = 0.2) has the highest value (c / a = 4.602) and highest value of crystal size (D = 84.7 nm). The four - sensor procedure was achieved to detection the transition temperature Tc and the results confirmed the metal behavior of all samples. There was a change in the critical temperature, which increased from (111 to 119) Kelvin when the concentration of lanthanum increased from zero to 0. 2 and became 114 K at x = 0. 4 and then decreased to (105 and 98) Kelvin at x = 0.6 and 0.8.

Absorption edge parameters of the LIII edge for compounds of Hg, Tl, Pb and Bi using EDXRF technique

The measurement of Absorption edge parameters of the LIII edge of pure elements Hg, Tl, Pb and Bi along with their compounds HgCl2, HgO, HgF2, TlCl, Tl2O3, PbCl2, PbF2, Pb3O4, BiF3, BiCl3 and Bi2O3 has been done using EDXRF technique. In the present measurements 241Am (59.54keV) radioactive source of activity 100mCi along with CANBERRA make cryo-cooled Si (Li) detector is used. The measured results are compared with theoretically calculated values from FFAST version 2.1 (Chantler et al., 2005) and shows good agreement with each other within experimental uncertainties within 3.5%. It is observed that the values of absorption edge parameters of the LIII edge depends slightly on the chemical environment and shows almost constant behaviour with effective atomic number (Zeff)

One-pot Sonochemical Synthesis of Hg–Ag Alloy Microspheres from Liquid Mercury

Metallic mercury has always attracted much attention in various fields because of its unique characteristic of forming amalgams. Here, different phases of pure crystalline Hg–Ag amalgam microspheres are synthesized by ultrasonically reacting liquid mercury with an aqueous solution of silver nitrate. Sonicating different molar ratios of liquid metallic Hg with AgNO3 results in the formation of pure crystalline phases of solid silver amalgams with uniform morphology. The resulting Hg–Ag amalgams from various compositions after sonication are physically characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Differential Scanning Calorimetry (DSC). The XRD of the amalgams obtained from the molar ratios of Hg:Ag (1:1.5) and Hg:Ag (1.5:1 and 2:1) match the Schachnerite and Moschellandbergite phases, respectively, whereas the Hg–Ag amalgam prepared from a 1:1Hg:Ag molar ratio results in a mixture of the Schachnerite and Moschellandbergite phases. The obtained amalgam microspheres are between 6 and 10µm in size. The detailed thermal and chemical behaviour of the Ag–Hg systems is also investigated.

Fate of mercury in flue gas desulfurization gypsum determined by Temperature Programmed Decomposition and Sequential Chemical Extraction

A considerable amount of Hg is retained in flue gas desulfurization (FGD) gypsum from Wet Flue Gas Desulfurization (WFGD) systems. For this reason, it is important to determine the species of Hg in FGD gypsum not only to understand the mechanism of Hg removal by WFGD systems but also to determine the final fate of Hg when FGD gypsum is disposed. In this study, Temperature Programmed Decomposition (TPD) and Sequential Chemical Extraction (SCE) were applied to FGD gypsum to identify the Hg species in it. The FGD gypsum samples were collected from seven coal-fired power plants in China, with Hg concentrations ranging from 0.19 to 3.27μg/g. A series of pure Hg compounds were used as reference materials in TPD experiments and the results revealed that the decomposition temperatures of different Hg compounds increase in the order of Hg2Cl2<HgCl2<black HgS<Hg2SO4<red HgS<HgO<HgSO4. The Hg compounds existing in FGD gypsums identified by TPD included HgCl2, Hg2Cl2, Hg2SO4, black HgS and red HgS, of which mercury sulfides were the primary compounds. The results of SCE indicated that Hg was mainly distributed in the strongly complexed phase. The low Hg content in FGD gypsum increases the ambiguity of assigning extraction fractions to certain Hg species by SCE. The fact that the primary compounds in FGD gypsum are HgS phases leads the leaching of Hg in the natural environment to be quite low, but a considerable amount of Hg may be released during the industrial heating process.

Polymeric nanocomposites made of a conductive polymer and a thermosensitive hydrogel: Strong effect of the preparation procedure on the properties

Nanocomposites are made by loading a conductive polymer (polyaniline, PANI) inside a thermosensitive hydrogel matrix (poly(N-isopropylacrylamide)-co-(2-acrylamido-2-methylpropane sulfonic acid), HG). The composites were obtained by two loading methods: i) in-situ polymerization of aniline inside the hydrogel matrix (ISP) and ii) by swelling of hydrogel in a true solution (SIS) of PANI (base) in N-methylpyrrolidone. Even though the composites have similar chemical composition, scanning electronic microscopy (SEM) shows different morphologies for each material obtained. ISP produces a material with segregated nanodomains of PANI inside HG, building a true nanocomposite (NC). On the other hand, SIS seems to create a semi-interpenetrated (semi-IPN) network of PANI inside the HG. The swelling capacity and volume phase transition temperature (VPTT) of composites are also affected by the loading methods. The segregated nanodomains of PANI in the NC do not affect the thermosensitivity of HG, while the PANI chains are directly interacting with the HG chains in the semi-IPN, affecting the VPTT. The swelling capacity of NC is of %Sweq = 6500 while the semi-IPN is of %Sweq = 8600. Both of them are lower than the one of pure HG (%Sweq = 11,000). The elastic module of both materials is higher than HG. The states of water analyzed by DSC show a high hydrophobic character inside the composite. The amount of water interacting with HG chains decreases with the presence of PANI. Both composites show electronic conductivity which changes when pressure is applied on them. However the NC shows a larger gauge factor. Such property could be applied in a pressure sensor. Additionally, the thermal sensitivity of the matrix is coupled with the electronic conductivity of PANI, allowing to build an electric switch controlled by the temperature.

Temperature stability of mercury compounds in solid substrates

Abstract The major aim of the newly adopted Mercury Convention is to reduce global mercury (Hg) emissions to the environment. In high temperature industrial processes, including coal combustion, Hg compounds present as impurities in solid materials are decomposed and evaporated leading to the emission of Hg to the atmosphere. The behaviour of different Hg compounds and their mixtures during heating have been the subject of numerous studies, and is the topic of the present work. Controlled heating can be used to fractionate Hg compounds in solid substrates, offering the possibility of identification and quantification of Hg compounds. In the attempt to develop a method for temperature fractionation of Hg, experiments were conducted with pure Hg compounds, and the compounds mixed with different substrates (SiO2 and CaSO4 • 2H2O), for calibration purposes. Detection was performed by two methods, namely Cold Vapour Atomic Absorption Spectrometry (CV AAS) with Zeeman background correction, and Nier-type Mass Spectrometry with a Knudsen cell (MS). Further investigation is in process.

Pyrometric cathode temperature measurements in metal halide lamps

Time-averaged temperature distributions along the electrodes of vertically operated high-intensity discharge lamps with cylindrical quartz burners filled with mercury and additives of NaI, TlI and DyI3 have been measured. The lamps have been driven by 120 Hz switched-dc currents between 0.4 and 1.78 A and the measurements have been performed during the cathodic phase at the lower electrode. All considered currents are characterized by a diffuse arc attachment. For the correction of disturbing effects the measured distributions have been fitted with solutions of the quasi-one-dimensional and steady-state energy balance of a rod-shaped tungsten cathode. A model of the near-cathode layer in a multi-species plasma has been applied for the determination of the boundary layer characteristics where the work function has been treated as a free parameter. The required plasma component concentrations have been estimated from spectroscopic measurements in the arc column. The fit procedure includes the adjustment of the extension of the lateral arc attachment region which has a distinct impact on the determined tip temperature, power input from the plasma into the cathode and the work function. For the latter the tungsten value has been verified in the pure Hg lamp, but strong deviations result in the case of a TlI admixture. The lamp with DyI3 clearly shows the gas-phase emitter effect of lowering the work function induced by Dy.

In situ X-ray studies of adlayer-induced crystal nucleation at the liquid-liquid interface.

Crystal nucleation and growth at a liquid-liquid interface is studied on the atomic scale by in situ Å-resolution X-ray scattering methods for the case of liquid Hg and an electrochemical dilute electrolyte containing Pb(2+), F(-), and Br(-) ions. In the regime negative of the Pb amalgamation potential Φ(rp) = -0.70 V, no change is observed from the surface-layered structure of pure Hg. Upon potential-induced release of Pb(2+) from the Hg bulk at Φ > Φ(rp), the formation of an intriguing interface structure is observed, comprising a well-defined 7.6-Å-thick adlayer, decorated with structurally related 3D crystallites. Both are identified by their diffraction peaks as PbFBr, preferentially aligned with their axis along the interface normal. X-ray reflectivity shows the adlayer to consist of a stack of five ionic layers, forming a single-unit-cell-thick crystalline PbFBr precursor film, which acts as a template for the subsequent quasiepitaxial 3D crystal growth. This growth behavior is assigned to the combined action of electrostatic and short-range chemical interactions.

Re-analysis of the critical nucleation work in the case of diffusive interface

Regarding the inherent limitations of previous thermodynamic description on nucleation, the nucleation work has been re-analyzed for undercooled melts by introducing temperature- and position-dependent thermodynamic quantities in the diffusive interface. At the small undercoolings, the obtained critical nucleation work matches that derived from the classical nucleation theory. With the increasing undercooling, the nucleation work approaches and finally becomes smaller than that from the published theories based on the diffusive interface. Substituting the critical nucleation work predicted by the present approach into the steady-state homogeneous nucleation rate, the nucleation rates for pure Hg and Ga have been calculated. It is shown that the results from the present approach fit the experimental values much better than those from the classical nucleation theory. Particularly, for some metals or alloys, the temperature at which the nucleation work vanishes can be predicted using the present approach.

Mercury dynamics in lake sediments

Triplicate porewater depth-profiles of pH and concentrations of total Hg (HgT), methylmercury (MeHg), Fe, Mn, sulfate, total sulfide, total zero-valent sulfur, organic C and major ions were determined at two sampling dates in a perennially oxygenated basin and a seasonally anoxic basin from Lake Tantaré, a Canadian Shield lake. The vertical distribution of HgT, MeHg, acid volatile sulfide, total S, Fe, Mn, Al and organic C were also determined in dated sediment cores from the same lake basins and from the deepest site of two other lakes, one also located in the Canadian Shield and the other in the Northeastern part of the Appalachian Mountains. Application of a one-dimensional transport-reaction equation to the dissolved HgT and MeHg profiles constrains the depth intervals (zones) where these species are produced or consumed in the sedimentary column and yields estimates of net reaction rates of HgT or MeHg in each of the zones as well as their fluxes at the sediment–water interface.Dissolved HgT and MeHg diffused from the overlying water into the sediments, except for MeHg at one of the sampling dates in the perennially oxygenated basin. About 97% and 50% of the MeHg flux to the sediments is presently deposited with settling particles in the perennially oxygenated and seasonally anoxic basins, respectively. Removal of porewater HgT and MeHg occurred at all dates and sampling sites. Comparison of the consumption zones of porewater HgT and MeHg with the profiles of ancillary parameters, coupled with thermodynamic calculations, suggest that pure Hg mineral phases do not form in the sediments, that HgT and MeHg adsorption onto authigenic Fe oxyhydroxides occurs in minor proportions, and that the association of HgT and MeHg to Fe sulfide phases or sulfidized organic matter is possible. Assuming that the net consumption of MeHg in the porewaters was essentially due to demethylation, an apparent first-order rate constant for MeHg demethylation of 0.04–0.8d−1 was estimated. Production of porewater MeHg occurred only in the perennially oxygenated basin, at sediment depths where SO4 was consumed. Assuming that the net production of porewater MeHg was essentially due to methylation, an apparent first-order rate constant for Hg methylation ranging between 0.006d−1 and 0.1d−1 was calculated. These field-derived Hg methylation and MeHg demethylation rate constant values are within the range of those derived from Hg-spiked experiments. We also show that the post-depositional redistribution of total Hg during the early stages of sediment diagenesis is minor and that the solid-phase HgT record can be used to reconstruct the evolution of the anthropogenic HgT deposition.

液体水銀-ルビジウム合金の X 線吸収端の挙動

The LI and LIII edges of Hg and the K edge of Rb in Hg-Rb alloys were measured by the absorption spectroscopy of X-rays. On increasing the Rb concentration, the absorption edges of Hg show an opposite behavior from each other, a decrease of LI and an increase of LIII compared with the case of pure liquid Hg. This difference was discussed from the polyanion formation of Hg atoms on alloying. With the increase of alkali concentration, the p like state of polyanion seems to be situated on the lower energy side than that of the s band. The electronic structure of this polyanion was discussed based on a simple LCAO analysis. Such an existence of polyanions may be responsible for the curious phenomena of liquid Hg-alkali alloys, the maximum of the electrical resistivity at 60 at% alkali and the positively enhanced tendency in the intermediate alkali concentration range of the magnetic susceptibility in the overall negative deviation.

Titrimetric analysis of total mercury ions including mercury(I) ions

A systematic analytical method is proposed and applied to directly determine the total concentra- tion of Hg(II) and Hg(I) ions in water. Experimental results demonstrate that this method provides a low detection limit of 0.05 mM and small relative error within 1.5% in an ion concentration range of 0.2- 50 mM. The technique is especially applicable for sample solutions that the traditional titration method like Volhard and EDTA complexation titrimetry could not analyze directly. This method could be employed to analyze solutions in any ratio of Hg(II) and Hg(I) ions including pure Hg(II) or pure Hg(I) ions, ex- hibiting several advantages, such as simple operation, good reproducibility, and low cost.

Small-angle x-ray scattering of supercritical fluid Hg: Bi-impurity effect

We have carried out small-angle x-ray scattering and x-ray transmission measurements of supercritical fluid Hg-0.2%Bi and pure Hg systems at SPirng-8 in Japan. We have obtained the static structure factors S(Q) in the low-momentum transfer region (0.5< Q <3 nm−1) for both samples at temperatures and pressures up to 1600 °C and 200 MPa. A Bi-impurity effect can be seen in both S(Q) and density deduced from x-ray transmission, only in the high temperature and high pressure region; the sign of the phase separation is seen near the critical density for Hg-0.2%Bi sample. We have analyzed S(Q) by Ornstein-Zernike formula and deduced the structure factors in the long-wavelength limit S(0), correlation lengths ξ, and corresponding short-range correlation lengths R = ξ≡/√S(0). Temperature variation of R is very similar to that of the density in each sample. This experimental fact hints that the variation of R is highly dependent on its metallic nature because the density is the most relevant parameter for the electronic features in fluid Hg and its impurity systems.

The Variation of Absorption Edges of X-Rays for Liquid Hg-Rb Alloys

The L I and L III edges of Hg and the K edge of Rb in liquid Hg-Rb alloys were measured by the absorption spectroscopy of X-rays. On increasing the Rb concentration, the absorption edges of Hg show an opposite behavior each other, the decrease of L I and the increase of L III compared with the case of pure liquid Hg. This difference was discussed from the polyanion formation of Hg atoms on alloying. With the increase of alkali concentration, the p like state or polyanion seems to be situated on the lower energy side than that of s band. The electronic structure of this polyanion was discussed based on a simple LCAO analysis. Such an existence of polyanions may be responsible to the curious phenomena of liquid Hg-alkali alloys, the maximum of the electrical resistivity at 60at% alkali and the positively enhanced tendency in the intermediate alkali concentration range of the magnetic susceptibility in the overall negative deviation.

Influence of Ga Content on Electrochemical Behavior of Mg-5 at%Hg Anode Materials

The effects of Ga content on the electrochemical behavior of Mg-5 at%Hg alloys which contain a small amount of Ga was investigated by the measurement of polarization curves and galvanostatic test. The microstructure of the alloys and the surface of the specimens corroded in galvanostatic test were observed by using scanning electron microscopy, energy spectrum analysis and X-ray diffraction analysis. It can be concluded that with the content of Ga increasing, the alloys come into Mg-Mg 3 Hg, Mg-Mg 7.2 (Hg, Ga) 2.8 and Mg-Mg 5 Ga 2 binary phase fields sequentially. The best electrochemical activity occur in the Mg-5 at%Hg -1 at%Ga alloy, with open circle potential -2.124V and mean potential -1.992 V. The corrosion resistance of the alloys is in the sequential order from big to small: Mg-5 at%Hg-5 at%Ga, Mg-5 at%Hg-22 at%Ga, Mg-5 at%Hg-1 at%Ga, Mg-5 at%Hg. The lowest corrosion current density is 0.418 mA·cm -2 . The activation mechanism of the magnesium alloy produced by Hg and Ga was concluded: the dissolution of Hg and Ga atoms leads to the back accumulation of liquid Hg and Ga, which makes a true metallic contact with a-Mg. Magnesium atoms diffuse through the liquid mercury and gallium to form magnesium amalgam and undergo severe oxidation at the amalgam/electrolyte interface. The reaction produces pure Hg and Ga again which continue the activation process.

Mercuric cyanide as a receptor of pyrene

Cocrystallization of pyrene with Hg(CN)(2) gives a new clathrate, namely bis[dicyanidomercury(II)] pyrene solvate, [Hg(CN)(2)](2) x C(16)H(10), with molecules of pyrene embedded in cavities of the slightly deformed structure of the mercuric salt; the weak intermolecular N...Hg interactions present in pure Hg(CN)(2) are maintained in the cocrystal. The X-ray analysis of the resulting compound reveals unusual organic-inorganic interactions. One molecule of Hg(CN)(2) lies on a crystallographic mirror plane, while in the other, only the Hg atom is on the mirror plane. The molecule of pyrene is cut by a mirror plane perpendicular to the plane of the molecule.

Temperature profiles and thermal losses in 150 W high-intensity discharge lamps

A series of 150 W quartz metal-halide test lamps containing four different chemistries has been studied with optical emission spectroscopy and x-ray absorption imaging. The four chemistries are pure Hg, Hg–HgI2, Hg–NaI and Hg–NaI–DyI3. Core temperatures and comprehensive distributions of Hg vapour densities were measured and combined to obtain comprehensive gas temperature distributions. The concentrations of additives in these specially designed test lamps were found to be much smaller than is typical for a commercial metal-halide lamp. As a consequence, the core temperatures in all lamps are largely characteristic of a pure Hg discharge. The gas temperature distributions have been used to determine power losses resulting from thermal conduction through the Hg vapour. The fraction of total input power dissipated thermally was found to be 0.49 ± 0.01 in pure Hg, similar to published measurements for such lamps. In the Hg–NaI and Hg–NaI–DyI3 lamps, thermal losses are 0.41 ± 0.01 and 0.42 ± 0.01, respectively. The Hg–HgI2 lamp has thermal losses of 0.29 ± 0.03.