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Sample records for alloy-yundk 25ba

  1. La2/5Ba2/5Ca1/5

    Indian Academy of Sciences (India)

    Unknown

    2003) are well known for their antiferromagnetic beha- viour as well as for their giant magnetoresistance. Substi- tution of La by monovalent alkali or divalent alkaline earth metal ions induces ferromagnetic behaviour in these oxides. Such substitution of lower valent ions for La3+ ions results in mixed valence at the Mn site, ...

  2. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. Kandalam V Ramanujachary. Articles written in Bulletin of Materials Science. Volume 28 Issue 6 October 2005 pp 571-577 Ceramics and Glasses. (La2/5Ba2/5Ca1/5)(Mn(2/5)–NiTi3/5)O3: Rietveld studies, dielectric and magnetic properties of new perovskite-related oxides.

  3. Saroj L Samal

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. Saroj L Samal. Articles written in Bulletin of Materials Science. Volume 28 Issue 6 October 2005 pp 571-577 Ceramics and Glasses. (La2/5Ba2/5Ca1/5)(Mn(2/5)–NiTi3/5)O3: Rietveld studies, dielectric and magnetic properties of new perovskite-related oxides.

  4. Optimization of fly ash and bottom ash substitution against paving block manufacture according to SNI 03-0691-1996

    Science.gov (United States)

    Karolina, R.; Syahrizal; Bahri, N.

    2018-02-01

    The waste of coal burning has a very negative impact on the environment if the waste is not managed as well as possible. The remaining waste of coal combustion consists of fly ash and bottom ash. FA and BA can be developed into substitution materials in the process of making paving blocks. The purpose of this study was to determine the quality of paving block in accordance with SK SNI 03-0691-1996 with optimization in the use of FA and BA. This study uses a 351 paving block sample size of 20x10x6 cm. Paving blocks are divided by 4 categories, namely normal paving block, paving block with FA substitution, BA substitution and combination of FA-BA with each variation 0%, 25%, 50%, 75% and 100%. Each variation amounted to 27 samples. Paving block quality measurement is done through 4 tests: absorption, compressive strength, sodium sulphate resistance and Los Angeles tests. The result of the test shows the absorption of normal paving block is 3,229%, paving block with 25% FA is 3,889%, paving block with 50% BA is 5,560% and paving block with 25% FA-BA combination is 5,794%. Compressive strength in normal paving block is 25,50 MPa, paving block with 25% FA is 25,28 MPa, paving block with 25% BA is equal to 27,61 MPa and paving block with 25% FA-BA is 26, 00 MPa. In testing of sodium sulfate resistance, almost all test specimens are eligible except for paving block with 50% FA and 75% FA. In the test of wear resistance, no specimen is eligible according to SK SNI 03-0691-1996. The comparison of the strength of the test specimen can be seen in substitution with 25% BA which reaches maximum strength.

  5. Indoor/Outdoor Air Quality Assessment at School near the Steel Plant in Taranto (Italy

    Directory of Open Access Journals (Sweden)

    A. Di Gilio

    2017-01-01

    Full Text Available This study aims to investigate the air quality in primary school placed in district of Taranto (south of Italy, an area of high environmental risk because of closeness between large industrial complex and urban settlement. The chemical characterization of PM2.5 was performed to identify origin of pollutants detected inside school and the comparison between indoor and outdoor levels of PAHs and metals allowed evaluating intrusion of outdoor pollutants or the existence of specific indoor sources. The results showed that the indoor and outdoor levels of PM2.5, BaP, Cd, Ni, As, and Pb never exceeded the target values issued by World Health Organization (WHO. Nevertheless, high metals and PAHs concentrations were detected especially when school were downwind to the steel plant. The I/O ratio showed the impact of outdoor pollutants, especially of industrial markers as Fe, Mn, Zn, and Pb, on indoor air quality. This result was confirmed by values of diagnostic ratio as B(aP/B(gP, IP/(IP + BgP, BaP/Chry, and BaP/(BaP + Chry, which showed range characteristics of coke and coal combustion. However, Ni and As showed I/O ratio of 2.5 and 1.4, respectively, suggesting the presence of indoor sources.

  6. Structural, dielectric and magnetic properties of Mn modified xBiFeO{sub 3}-(1−x)BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Zhonghua, E-mail: zhdai@mail.xjtu.edu.cn [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Liu, Lu; Ying, Guobing; Yuan, Ming [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ren, Xiaobing [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

    2017-07-15

    Manganese doped xBiFeO{sub 3}-(1−x)BaTiO{sub 3}(x=0.67–0.82) ceramics were prepared by solid-state method. The structural, dielectric and magnetic properties were investigated after annealing in vacuum at 773 K. X-ray diffraction analysis indicated that all samples crystallized in pure perovskite structure. The ceramics displays a typical ferroelectric loop, with a max remnant polarization P{sub r} of 25.6 µC/cm{sup 2}. The piezoelectric coefficient d{sub 33} of Manganese doped 0.67BiFeO{sub 3}0.33BaTiO{sub 3} is 139 pC/N and its temperature dependence of dielectric constant exhibits a broad anomaly. The Manganese doped 0.75BiFeO{sub 3}0.25BaTiO{sub 3} ceramic shows ferrimagnetism at room temperature, with remnant magnetization M{sub r} of 0.31 emu/g and ferrimagnetic transition temperature T{sub N} of ~420 °C. - Highlights: • In this manuscript, a technique combined Mn doping which is able to fabricate point defects and annealing in vacuum which can stabilize the unstable ion was investigated. We studied the electrical properties of Mn doped BiFeO{sub 3}-BaTiO{sub 3} ceramics after vacuum annealing treatment at appropriate temperature. • Our result is that Mn modification and heat treatment are effective methods to solve the problem of high leakage of BiFeO{sub 3}-BaTiO{sub 3} system ceramic prepared by solid-state method. It exhibited a enhanced field-induced ferromagnetic ordering with promising potential in spintronics and recording media applications.

  7. Methylomic profiling of cortex samples from completed suicide cases implicates a role for PSORS1C3 in major depression and suicide

    Science.gov (United States)

    Murphy, T M; Crawford, B; Dempster, E L; Hannon, E; Burrage, J; Turecki, G; Kaminsky, Z; Mill, J

    2017-01-01

    Major depressive disorder (MDD) represents a major social and economic health issue and constitutes a major risk factor for suicide. The molecular pathology of suicidal depression remains poorly understood, although it has been hypothesised that regulatory genomic processes are involved in the pathology of both MDD and suicidality. In this study, genome-wide patterns of DNA methylation were assessed in depressed suicide completers (n=20) and compared with non-psychiatric, sudden-death controls (n=20) using tissue from two cortical brain regions (Brodmann Area 11 (BA11) and Brodmann Area 25 (BA25)). Analyses focused on identifying differentially methylated regions (DMRs) associated with suicidal depression and epigenetic variation were explored in the context of polygenic risk scores for major depression and suicide. Weighted gene co-methylation network analysis was used to identify modules of co-methylated loci associated with depressed suicide completers and polygenic burden for MDD and suicide attempt. We identified a DMR upstream of the PSORS1C3 gene, subsequently validated using bisulfite pyrosequencing and replicated in a second set of suicide samples, which is characterised by significant hypomethylation in both cortical brain regions in MDD suicide cases. We also identified discrete modules of co-methylated loci associated with polygenic risk burden for suicide attempt, but not major depression. Suicide-associated co-methylation modules were enriched among gene networks implicating biological processes relevant to depression and suicidality, including nervous system development and mitochondria function. Our data suggest that there are coordinated changes in DNA methylation associated with suicide that may offer novel insights into the molecular pathology associated with depressed suicide completers. PMID:28045465

  8. Dynamic Assessment of Incidental Vocabularies: A Case of Iranian ESP Learners

    Directory of Open Access Journals (Sweden)

    Sepideh Hanifi

    2016-04-01

    Full Text Available Dynamic assessment (DA, stemmed from both Vygotsky’s (1978 learning theory and Feuerstein’s (1979 theory of mediated learning experiences, is an alternative to static assessment. It focuses on both instruction and assessment aiming at promoting learning through mediation.  DA has been widely researched in different linguistic areas, but there is paucity of research on its practice in ESP contexts. Accordingly, this study investigated the effectiveness of DA on incidental vocabularies emerging in technical reading textbooks, written for electronic engineering students. The study employed a quasi-experimental research design. Due to sample selection problems, an intact group of 25 BA electronic students were selected from the University of Zanjan. A pre-test was administered to check whether they had previous knowledge of the target words, incidentally acquired during the reading activity. As for the instrument stage, DA procedures were utilized in order to individualize participants’ assessment. Following DA implementation, a post-test similar in content to pre-test, was administered to the same participants. The significance of DA for the enhancement of incidental vocabularies was to make participants aware of the strategies of identifying, evaluating and monitoring vocabularies (Nassaji, 2003 through mediation process.  The results indicated that participants' incidental vocabulary learning promoted dramatically using DA, which employed structured hints for the mediation process.  The results of this study can inform both teachers and learners to provide a step by step procedure to promote both teaching and assessment of ESP learners' vocabulary. Keywords: Dynamic Assessment, Incidental Vocabulary Learning, ESP Learners, ZPD, mediation

  9. Effect of Ba in the glass characteristics of cesium loaded iron phosphate glasses

    International Nuclear Information System (INIS)

    Joseph, Kitheri; Asuvathraman, R.; Vasudeva Rao, P.R.

    2015-01-01

    Radioactive 137 Cs extracted from high level nuclear waste, when immobilized in a suitable matrix can be used as a γsource in medical industry. Iron phosphate glass (IPG) is one of a suitable matrix for the immobilization of 137 Cs prior to the immobilization of 137 Cs in IPG, it is essential to optimize the immobilization conditions using natural (inactive) cesium. Glass characteristics of inactive Cs loaded iron phosphate glasses were already explored in our earlier studies. However, the change in glass characteristics of 137 Cs loaded iron phosphate glass to 137 Ba loaded iron phosphate glass need to be studied before the immobilization of 137 Cs in iron phosphate glass as 137 Cs transforms to 137 Ba due to nuclear transmutation ( 137 Cs(β,γ) 137 Ba). This paper reports the studies on such a behaviour by incorporating inactive Ba in cesium loaded iron phosphate glasses. Cs and Ba loaded iron phosphate glasses were prepared by melt quench technique in air using appropriate amounts of Fe 2 O 3 , NH 4 H 2 PO 4 , Ba(OH) 2.8 H 2 O and Cs 2 CO 3 . The chemicals were added such that the glass formed possesses the batch composition of (a) 21.4 wt. % Fe 2 O 3 -45 wt. % Cs 2 O-5 wt % BaO-P 2 O 5 (henceforth referred as IP50Cs45Ba5); (b) 21.4 wt. % Fe 2 O 3 -25 wt. % Cs 2 O-25 wt % BaO-P 2 O5 (henceforth referred as IP50Cs25Ba25). The thermal expansion measurements were also carried out using a home-built quartz push-rod dilatometer. The data related to change in thermal expansion behaviour, glass forming ability, glass stability and structural changes in phosphate network due to the partial replacement of Cs with Ba will also be discussed. (author)

  10. Magnetoelectric and electric measurements of the (1-x)BiFeO{sub 3}–(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bochenek, D., E-mail: dariusz.bochenek@us.edu.pl [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Niemiec, P. [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Guzdek, P. [Institute of Electron Technology Cracow Division, 39, Zabłocie St., Cracow, 30-701 (Poland); Wzorek, M. [Institute of Electron Technology, Al. Lotników 32/46, 02-668, Warsaw (Poland)

    2017-07-01

    In the paper ferro–electro–magnetic (1-x)BiFeO{sub 3}-(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} (BF-PFN) solid solutions were obtained (containing the percentage BF/PFN: 60/40 and 70/30). Individual components of the solid solution were prepared by follows methods: synthesizing a powder BF was performed by calcining the simple oxides (Bi{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}), and synthesizing a powder PFN was carried out by calcining a mixture of complex oxides (FeNbO{sub 4}, PbO). Compaction of synthesized and mixed BiFeO{sub 3}, PbFe{sub 1/2}Nb{sub 1/2}O{sub 3} powders was carried out by free sintering methods. X–ray, microstructure, dielectric, magnetic and magnetoelectric studies, DC electrical conductivity and electrical hysteresis loop were carried out. Magnetoelectric effect measurements performed at room temperature showed coupling between electric and magnetic subsystem of the BF–PFN solid solutions. - Highlights: • BF-PFN samples have a densely packed microstructure, with well crystallized grains. • Bi atoms possibly migrate from BF toward PFN component during sintering. • BF-PFN have a diffuse character of the ferroelectric–paraelectric phase transition. • Magnetoelectric coefficient (α{sub ME}) for BF-PFN is higher, than for pure BF. • The α{sub ME} for BF-PFN is about three times higher than for 0.75BiFeO{sub 3}–0.25BaTiO{sub 3}.

  11. Magnetoelectric and electric measurements of the (1-x)BiFeO3–(x)Pb(Fe1/2Nb1/2)O3 solid solutions

    International Nuclear Information System (INIS)

    Bochenek, D.; Niemiec, P.; Guzdek, P.; Wzorek, M.

    2017-01-01

    In the paper ferro–electro–magnetic (1-x)BiFeO 3 -(x)Pb(Fe 1/2 Nb 1/2 )O 3 (BF-PFN) solid solutions were obtained (containing the percentage BF/PFN: 60/40 and 70/30). Individual components of the solid solution were prepared by follows methods: synthesizing a powder BF was performed by calcining the simple oxides (Bi 2 O 3 , Fe 2 O 3 ), and synthesizing a powder PFN was carried out by calcining a mixture of complex oxides (FeNbO 4 , PbO). Compaction of synthesized and mixed BiFeO 3 , PbFe 1/2 Nb 1/2 O 3 powders was carried out by free sintering methods. X–ray, microstructure, dielectric, magnetic and magnetoelectric studies, DC electrical conductivity and electrical hysteresis loop were carried out. Magnetoelectric effect measurements performed at room temperature showed coupling between electric and magnetic subsystem of the BF–PFN solid solutions. - Highlights: • BF-PFN samples have a densely packed microstructure, with well crystallized grains. • Bi atoms possibly migrate from BF toward PFN component during sintering. • BF-PFN have a diffuse character of the ferroelectric–paraelectric phase transition. • Magnetoelectric coefficient (α ME ) for BF-PFN is higher, than for pure BF. • The α ME for BF-PFN is about three times higher than for 0.75BiFeO 3 –0.25BaTiO 3 .

  12. Luminescent properties of Sr2.5−3x/2Ba0.5SmxAlO4F oxyfluorides

    International Nuclear Information System (INIS)

    Park, Sangmoon

    2012-01-01

    Effective orange Sm 3+ -doped Sr 2.5 Ba 0.5 AlO 4 F phosphors excited at 254 and 408 nm excitation were prepared by the solid-state method. The excitation and emission spectra of Sr 2.5−3x/2 Ba 0.5 Sm x AlO 4 F and Sr 2.5−3x/2 Ba 0.5 Sm x AlO 4−α F 1−δ (x=0.001∼0.1) based on photoluminescence spectroscopy are investigated. The defects in anion-deficient Sr 2.5−3x/2 Ba 0.5 Sm x AlO 4−α F 1−δ (x=0.001, 0.01) are monitored by broad-band photoluminescence emission centered near 480 nm along with the orange emission transitions of Sm 3+ . CIE values and relative luminescent intensities of Sr 2.5−3x/2 Ba 0.5 Sm x AlO 4 F and Sr 2.5−3x/2 Ba 0.5 Sm x AlO 4−α F 1−δ by changing the Sm 3+ content (x=0.001∼0.1) are discussed. - Highlights: ► Under the excitation of 408 nm competent orange emitting Sr 2.5−3x/2 Ba 0.5 Sm x AlO 4 F phosphor is initiated. ► Sm 3+ -activated oxyfluoride phosphor is quite effective to prepare white-emitting light for near-UV LED applications. ► Defects could be visibly created in the Sr 2.5−3x/2 Ba 0.5 Sm x Al O 4 F host lattices when Sm 3+ ions are doped less than 5 mol %. ► The gradual substitution of Sm 3+ contents in oxyfluoride hosts is amenable to change CIE values and desired emitting intensity.

  13. Pure and Y-substituted BaZrO3 ceramics. A possible support material for fabrication of YBa2Cu3O7-x high-Tc superconductors

    International Nuclear Information System (INIS)

    Wang Xiandong.

    1993-01-01

    This thesis concerns the preparation and characterization of cuprate based high-T c superconductors (Y-123 and Bi-2223) and especially development and testing of BaZrO 3 based materials. The formation of YBa 2 Cu 3 O y (Y-123) by a CO 2 -free route involving reaction sintering of stoichiometric mixtures of chemically prepared fine powders of Y 2 BaCuO 5 , BaCuO 2 and CuO have been studied by thermal and XRD analysis. The synthesis and sintering of BaZrO 3 powders prepared by the hydroxide-alkoxide-methanol sol-gel route have been studied. The phase relations in the system BaO-Y 2 O 3 -ZrO 2 have been studied to determine the solid solubility limits for the perovskite phase Ba X Y Y Zr Z O N (X+X+Z=3) at 1500 deg. C. In the binary system Y 2 O 3 -BaZrO 3 the solubility limit was found to be ≅19 mol% Y 2 O 3 , i.e. Ba 0.81 Y 0. 4 2 Zr 0.81 O 3 . along the joint BaYO 2.5 -Ba the boundary was determined to be at BaY 0.21 Zr 0 . 79 O 2.895 . evidence for a new solid solution series between Ba 3 Y 4 O 9 and ZrO 2 are given, and a partial 1500 deg. C phase diagram for the ternary system BaO-Y 2 O 3 -ZrO 2 is presented. The growth of BaZrO 3 single crystals have been attempted both by a laser zone floating technique and flux methods. The compatibility between YBa 2 Cu 3 O 7 -X and BaZrO 3 , Ba X Y Y Zr Z O 3-δ as well as BaHfO 3 have been studied at 950 deg. and 1050 deg. C. The results show the four most promising candidates as support materials for fabrication of YBa 2 Cu 3 O y to be BaHfO 3 , BaY 0.05 Zr 0.95 O 2.975 , , BaZrO 3 and BaY 0.1 Zr 0.9 O 2.95 . (EG)

  14. New Method of Preparation of Isomers of the (Ca0.1La0.9)(Ba1.6.5La0.35)Cu3Oy Superconductor with Predicted Maximal Tc

    International Nuclear Information System (INIS)

    Knizhnik, A.; Reisner, G.M.; Men, A.; Eckstein, Y.

    1998-01-01

    The 123 superconductor (Ca 0.1 La 0.9 )(Ba 1.6.5 La 0.35 )Cu 3 O y (c) has been prepared by the usual carbonate-oxide method. After oxygenation to the optimal oxygen doping of y=7.135, the maximal T c =57K. We prepared (c) also via reaction (1): 0.75La(La 0.25 Ba 1.75 )Cu 3 O 6.782 +0.25Ca 0.4 La 0.6 (La 0.65 Ba 1.35 )Cu 3 O 6.806 + 0.033O 2 (Ca 0. 1La 9 )(Ba 1.65 La 0.35 )Cu 3 ) 6.854 (1) The initial reagents are also superconductors. The first (a) has a maximal T c =57K, second (b) - 81K. In reference [1] we have shown that several isomers having the same general formula (c), may exist each having different ratios of the follow- ing possible unit cells: LaBa 2 Cu 3 O y , La(BaLa)Cu 3 O y , LaLa 2 Cu 3 O y , CaBa 2 Cu 3 O y , Ca(BaLa)Cu30 , CaLa2Cu30 . These isomers are formed at different temperatures of the preparation of (c) by carbonate-oxide method [1]. After the formation of compound (c) has been completed, further heating, even to higher temperatures, cannot change one isomer into another. Thus, there is no equilibrium between the (c) isomers and, if there also is no equilibrium in the cases of both isomers (a) and (b), then reaction (1) should not change the ratio of the unit cells. Each cell (i), which is present in (a) in concentration q i (a), should be present in (c) in concentration 0.75q i (a); analogously, each cell (i) which is present in (b) in concentration q i (b) should be present in (c) in concentration 0.25q i (b). According to the cluster component method, [2], T cmax = Σq i T i , where T i is T cmax of such a hypothetical sample, which contains cells (i) only. Thus the expected T cmax of (c), prepared via reaction (1), is: Σ0.75q i (a)T i + Σ0.25q i (b)T i = 0.75 x 57 + 0.25 x 81 = 63K, i.e. higher by 6 degrees than the T cmax of (c) prepared by the usual method. We studied reaction (1) via X-ray diffraction. XRD spectra showed that the intensity of the reagents peaks decrease with the time of the reaction and after 100 hours at 950 deg

  15. End-member fluids for diamond formation and their possible sources

    Science.gov (United States)

    Navon, O.; Weiss, Y.; Klein-Bendavid, O.; Bell, D. R.

    2009-04-01

    Microinclusions in fibrous diamonds carry high density fluids (HDF) with compositions that vary between silicic, carbonatitic and saline end-members. Combining EPMA and FTIR data we can estimate the composition of each end-member. The silicic end-member composition (Udachnaya) comprises ~90 wt% silicates, 4% carbonate, 4% water and minor apatite. The saline end-member (Diavik, Canada) carries 51 wt% alkali halides, 12% carbonates and 37% water. Klein-BenDavid et al. (in review) defined two carbonatitic end-members. The low-Mg one carries ~75 wt% carbonates, 11% silicates, 5% halides, 2% apatite and 7% water; the high-Mg end-member carries similar proportions, except for the higher apatite: 78% carbonates, 9% silicates, 5% apatite, 2% halides and 6% water, but with much higher Mg/(Mg+Fe+Ca) ratio. The volatile-free oxides proportions of the most silicic microinclusions in an Udachnaya diamond are: 69 wt% SiO2; 14% Al2O3; 10% K2O, 2% Na2O, 1% CaO and P2O5 and minor FeO, TiO2, MgO, and Cl. The saline HDF carries 73 wt% KCl, 12% NaCl, 7% CaO, 2.5% MgO, 2.5% BaO, 1.5% FeO and 1.5% SiO2. In the low-Mg carbonatitic HDF calcium exceeds magnesium: ~21 wt% CaO, 18% FeO, 12% MgO, 22% K2O; 10% SiO2, 8% Na2O and minor TiO2, Al2O3, P2O5 and Cl, while in the high-Mg end-member MgO is the main oxide: ~29% MgO, 23% CaO, 7% FeO, 17% K2O, 8% SiO2, 9% Na2O, 2% P2O5 and Cl and minor BaO, TiO2, Cr2O3 and Al2O3 ( all values were calculated on volatile-free basis). Weiss et al., in a companion abstract, suggest that the four end-members form two arrays; one between the saline and the high-Mg carbonatitic compositions and the second between the silicic and the low-Mg carbonatitic ones. They further suggest that the first array represents a process that takes place in a peridotitic environment and the other in an eclogitic one. For example, the arrays may be formed by interaction of hydrous or saline fluids with carbonate-eclogite or with carbonate-peridotite. Safonov et al. (2007) suggested that a saline melt can interact with silicate minerals to form immiscible silicic melt that may later evolve into a carbonatitic HDF. In an ultramafic environment a saline melt may evolve along the array to high-Mg carbonatites without forming an immiscible silicate melt (Safonov, 2008). The source of the saline fluid is not clear. It may be present as discrete halides or as a grain-boundary phase in the carbonate-bearing rock, or it may form deeper in the mantle and migrate upwards either as a saline melt, or as a hydrous fluid that is concentrated enough to preclude interaction with the mantle rocks it traverses. A second alternative is to introduce the carbonate as the penetrating fluid in the form of carbonatitic melt. A third alternative involves the upward migration of CH4 and heavier hydrocarbons. Such a fluid should be stable in eclogitic or peridotitic environments, as long as the oxygen fugacity is low enough. During ascent, such fluids migrate to more oxidized regions and eventually will react with the mantle rocks to form C+H2O (Luth, 1993; Malkovets et al. 2007) and later CO2. In eclogitic rocks, the water will react to form a silicic HDF and the C may precipitate as diamond. In a peridotitic environment, at temperatures below the carbonate solidus, such water may leach and dissolve K and Cl from the rock and evolve into a saline HDF. Temperature increase or further diamond oxidation may initiate the formation of carbonatitic HDF's.